REMEDIAL ACTION OBJECTIVES AND PRELIMINARY REMEDIAL … · remedial action objectives and preliminary remedial g oals • Future Commercial/Industrial Workers – A commercial/industrial

F I N A L T E C H N I C A L M E M O R A N D U M

American Creosote Works Superfund Site Feasibility Study Remedial Action Objectives and Preliminary Remedial Goals PREPARED FOR:

PREPARED BY:

DATE:

PROJECT:

DCN:

Michael Hebert /EPA Region 6 Remedial Project Manager Kenneth Shewmake/EPA John Halk/LDEQ CH2M HILL January 22, 2015 EPA Region 6 Remedial Action Contract EP-W-06-021 Task Order No. 0051-RIFS-06G3 CH2M HILL Project No. 411242.RS.01 0051-02029

This memorandum presents the remedial action objectives (RAO) and preliminary remediation goals (PRG) to be used in developing and evaluating remedial action alternatives for the draft American Creosote Works (ACW) feasibility study (FS). This memorandum is designed to seek stakeholder input, specifically on PRGs, in advance of preparing the draft FS report, so that the areas/volumes of contaminated media can be defined. Much of the information presented in this memorandum will be presented in the draft FS report.

This memorandum was developed in an iterative manner; therefore, there are several sections with redundant information. Specifically, Sections 1, 2, and 3 overlap with Section 4. Sections 1, 2, and 3 were added between the working draft and final version. This redundancy was preserved to maintain the memorandum’s original format.

1. BackgroundThe ACW site (the Site) is a former wood-treating facility that ceased operations in 1985. The Site, which spans approximately 62 acres (CH2M HILL, 2014a), is currently vacant except for ongoing subsurface/soil and groundwater remediation underway in the Site’s former process area (FPA) and a construction equipment storage area located in the southern portion of the Site.

Current exposures in the FPA are limited to personnel involved with site remediation, with public access restricted by a locking gate and perimeter fence. A layer of fill material, averaging approximately 1 foot in thickness, overlies a majority of the FPA. The cover material prevents direct contact with contaminated subsurface soil by remediation workers. Outside the soil cover footprint, where the potential for unacceptable health risks exists, remediation workers are protected through the use of personal protective equipment (PPE).

The future land use at the Site will be limited to industrial/commercial purposes through institutional controls (IC) to be implemented through a future Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) decision document. Based on current and foreseeable future site land use conditions, as part of the risk assessment presented in the Risk Assessment Version 1.1 (CH2M HILL, 2014), the Risk Assessment Addendum (CH2M HILL, 2014), and the American Creosote Works Superfund Site Decision Unit Preliminary Risk Evaluation by Media (Soil, Sediment and Surface Water) (CH2M HILL, 2014), the following potential current/future human exposure pathways were identified and evaluated:

• Current/Future Recreators in the Creek– Potential adolescent recreators could contact surface waterand sediment in Creosote Branch during recreational activities.

ACW SUPERFUND SITE FEASIBILITY STUDY REMEDIAL ACTION OBJECTIVES AND PRELIMINARY REMEDIAL GOALS.DOCX 1 EN0119151011SPB

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AMERICAN CREOSOTE WORKS SUPERFUND SITE FEASIBILITY STUDY REMEDIAL ACTION OBJECTIVES AND PRELIMINARY REMEDIAL GOALS

• Future Commercial/Industrial Workers – A commercial/industrial worker exposure scenario was evaluated for soil (0 to 10 feet deep), groundwater (potable use), and indoor air. Potential exposures to offsite and onsite groundwater were quantified for the industrial potable use exposure pathways and the groundwater-to-indoor air vapor intrusion (VI) pathway.

• Future Construction Workers – Potential construction workers were assumed to contact surface and shallow subsurface soil (0 to 10 feet deep) and shallow groundwater during site redevelopment or construction activities. Onsite and offsite shallow groundwater was evaluated for a construction worker, assuming a construction worker could potentially have direct contact with shallow groundwater during an excavation.

• Hypothetical Future Residents (Adult/Child) – A hypothetical future residential scenario was evaluated for soil (0 to 10 feet deep), groundwater (potable use), and indoor air. Potential exposures to offsite and onsite groundwater were quantified for the potable use exposure pathways and the groundwater-to-indoor-air VI pathway.

• Ecological – Risks to ecological receptors were also evaluated through direct and indirect (food web) exposure assessments, for both receptors in terrestrial (surface soil) and aquatic (sediment and surface water) habitats.

The contaminated media exposure to receptors that resulted in unacceptable risks will be identified for remedial action in the draft FS, and the PRGs are developed in this memorandum.

2. Decision Units The ACW site was divided into seven decision units (DU) to facilitate risk management decisions for the remedial investigation (RI) and FS. Following completion of the 2013 data gap sampling and the Risk Assessment Version 1.1 (CH2M HILL, 2014b), the Risk Assessment Addendum (CH2M HILL, 2014c), and the American Creosote Works Superfund Site Decision Unit Preliminary Risk Evaluation by Media (Soil, Sediment and Surface Water) (CH2M HILL, 2014d) it was determined that three of the seven DUs should be carried forward into the FS as follows:

1. Northern DU – surface soil. Maximum-based intake (doses) for the deer mouse yielded no observed adverse effect level (NOAEL), based hazard quotients (HQ) ranging from 3.4 to 30.4, which exceed the CERCLA target ecological HQ of 1.0 (see Table 1A) (reference Table 5-19, CH2M HILL, 2014b).

2. Non-Process Area – surface soil. The industrial worker excess lifetime cancer risk (ELCR) of 8.3 x 10-4 exceeded the upper bound CERCLA target risk of 1 x 10-4 (see Table 1B) (reference Table 1B, CH2M HILL, 2014d).

3a. Process Area – surface and subsurface soil. The industrial worker surface soil ELCR of 2.9 x 10-4 exceeded the upper bound CERCLA target risk of 1 x 10-4 (see Table 1B). The industrial worker subsurface soil ELCR of 1.4 x 10-3 also exceeded the upper bound CERCLA target risk of 1 x 10-4 (see Table 1B) (reference Table 1B, CH2M HILL, 2014d).

3b. Process Area and Non-Process Area shallow aquifer groundwater. This media was carried forward into the FS based on the following considerations:

• Shallow aquifer groundwater is not a current (Class IIA) drinking water source; however, based on U.S. Environmental Protection Agency (EPA) groundwater classification guidance (EPA, 1986a) shallow aquifer groundwater is considered a potential future (Class IIB) drinking water source. It is unlikely that onsite groundwater will be used as a potable source in the future because of relatively low yield and availability of water from the City of Winnfield. There is no indication that shallow aquifer groundwater is being used within the immediate vicinity of the Site. Drinking water for nearby residents is supplied by the City of Winnfield from deep wells constructed in the Sparta aquifer at estimated depths of 550 to 600 feet below ground surface (CDM, 1992). The nearest City


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of Winnfield water supply well is located approximately 0.5 mile north of the Site. Groundwater contamination in the shallow aquifer is limited to the Process Area DU and the western portion of the Non-Process Area DU.

• Per the National Contingency Plan (NCP) (40 Code of Federal Regulations [CFR] 300.430 [a][1][iii][F]), “EPA expects to return usable ground waters to their beneficial uses wherever practicable, within a timeframe that is reasonable given the particular circumstances of the site. When restoration of ground water to beneficial uses is not practicable, EPA expects to prevent further migration of the plume, prevent exposure to the contaminated ground water, and evaluate further risk reduction.”

• The concentrations of several site-related contaminants exceed federal drinking water maximum contaminant levels (MCL), which define chemical-specific applicable or relevant and appropriate requirements (ARAR) for groundwater that is a current or future drinking water source. For example, the 351 micrograms per liter (µg/L) exposure point concentration (EPC) for carcinogenic polycyclic aromatic hydrocarbons (PAH), expressed in benzo(a)pyrene (BAP) toxicity equivalents (TEQ), exceeds the 0.2 µg/L MCL. Exceedance of one or more chemical-specific ARAR is the primary basis for carrying shallow aquifer groundwater into the FS.

• The risk assessment identified future industrial/commercial worker VI/inhalation risk that fell within the CERCLA 1 x 10-4 to 1 x 10-6 target risk range. Although there is no unacceptable risk, the VI pathway will be addressed in the FS and a future CERCLA decision document, through ICs that will specify vapor mitigation controls (such as a vapor barrier) on all new (future) building construction within the Process Area DU. Human health exposure via vapor inhalation will be prevented through this IC, and risks will be reduced through implementation of remedial action alternatives that address contaminated soil and groundwater. These measures are designed to provide an additional level of protection to account for uncertainties in soil and groundwater contaminant concentrations and current and future vapor phase contaminant migration pathways.

• Shallow aquifer groundwater is in hydraulic communication with Creosote Branch Creek. Under the baseline (that is, no action) condition, contaminated groundwater discharge to the creek is assumed to result in surface water contaminant concentrations exceeding federal or state ambient water quality criteria (AWQC). Considering the current pumping and recovery of contaminated groundwater that retards shallow groundwater travel to the creek, all recent monitoring of surface water quality in Creosote Branch Creek indicates that the current soil and groundwater remedy is protective for the recreational and ecological exposure scenarios associated with the creek’s beneficial use.

2.1 Decision Units Not Carried Forward into the Feasibility Study • The DUs and media not carried forward into the FS include: • Northern DU subsurface soil and Northern DU shallow aquifer groundwater • Western DU surface soil • Southern DU surface and subsurface soil • Tar Mat Ash DU ash • Process Area/Non-Process Area deep aquifer groundwater • Creek DU surface water and sediment

Contaminant concentrations in these DUs did not exceed the upper bound of the CERCLA target risk range of 1 x 10-4 for carcinogenic constituents (Table 1B) or a hazard index (HI) of 1 for non-cancer constituents.

In the Creek DU, human health risk was evaluated using the 2013 data gap sampling results, assuming an adolescent recreator exposure scenario. The risk assessment estimated a cumulative ELCR of 2 x 10-6 and non-cancer HI of less than 1 for this exposure scenario. The samples used for the 2013 risk assessment were collected from the creek while the current remedy was operating. Therefore, the contaminant


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concentrations used to estimate Creek DU risks are biased low because the current remedy intercepts and prevents contaminated groundwater discharge to the creek.

A review of the baseline conditions present at the time of the 1992 RI was conducted to evaluate potential impacts to the creek prior to startup of the current remedy. Two surface water samples, which were collected in 1992 at the downstream boundaries of the Process Area DU and Non-Process Area DU, detected pentachlorophenol (PCP) at a concentration of 68 µg/L and 2,3,4,6-tetrachlorophenol at a concentration of 99 µg/L. It is not known if these detections were the result of groundwater or surface water (such as stormwater) discharge to the creek. Based on the sampling results, the 1992 RI report concluded the following:

In summary, the surface waters in the Creosote Branch do not appear to represent a significant threat to the environment as indicated by chemical analyses and toxicity tests of these waters. However, the sediments near the site represent a threat to the environment as indicated by the detection of contaminants of concern in chemical analyses and significant toxicity in the aquatic toxicity tests (CDM, 1992).

Although the 1992 RI report concluded there were no apparent impacts to surface water quality under the baseline condition, the detected PCP concentration of 68 µg/L exceeds the current EPA freshwater ambient water quality criteria critical maximum concentration (acute) of 19 µg/L and critical chronic concentration of 15 µg/L. Additionally, under the baseline condition, excluding any effects resulting from potential groundwater-surface water mixing, the concentration of other site-related contaminants at the groundwater-surface water interface would rise to a level comparable to that in shallow aquifer groundwater lying in the northern portion of the Process Area DU.

3. Contaminants of Concern for PRG Development This section describes the approach used to reduce the number of contaminants of concern (COC) carried forward for development of PRGs. As described in the risk assessment reports referenced in Section 2, historical releases of wood-treating chemicals resulted in contamination of soil and groundwater by many different volatile organic compounds (VOC) and semivolatile organic compounds (SVOC). Most of these constituents are co-located or were infrequently detected in the samples used to characterize risks. By developing PRGs for the COCs that account for a majority of the human health risk, the areas and volumes of contaminated media to be addressed in the draft FS and the methods used to define attainment of RAOs during the remedial action can be more efficiently determined.

3.1 COCs At the end of the risk assessment, a site-related contaminant was identified as a COC if its concentration corresponded to an ELCR of greater than 1x10-6 or a non-cancer HQ greater than 0.1, provided the cumulative ELCR or target HI for the receptor exceeded the upper-bound limit of the CERCLA risk range. Thus, the COC selection was based on an exceedance of cumulative ELCR of 1 x 10-4 and a HI of 1.0. All of the soil contaminants of potential concern (COPC) contributing to the ELCR above 1x10-4 to industrial workers, with a minimum individual COPC risk contribution of 1x10-6 or HI of 0.1 or higher, are identified as COCs. For the HI, the individual target organ specific cumulative HI has to exceed a value of 1.0, for the COPC to be identified as a COC.

3.2 Identification of Soil COCs for PRG Development Following issuance of the risk assessment reports and consultation with EPA and Louisiana Department of Environmental Quality (LDEQ), it was decided that because the site’s current and future land use would be industrial/commercial, the upper bound of the CERCLA target risk range would be applied for risk management decisions. Therefore, for the purposes of soil PRG development, the industrial land use based COCs identified in the risk assessment were selected as a starting point; those COCs with an ELCR contribution of greater than or equal to 10-6 or a HI greater than or equal to 0.1 were carried forward for PRG development. For ecological risks, a HQ greater than 1 was used to identify individual or contaminant


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groups as COCs for PRG development. Based on these thresholds, the following soil COCs were identified for PRG development:

1. Northern DU surface soil – The high molecular weight PAHs (HPAHs) benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[g,h,i]perylene, benzo[k]fluoranthene, chrysene, fluoranthene, indeno[1,2,3-cd]pyrene and pyrene (Table 1A) are identified as soil COCs for a terrestrial ecological protection end point.

2. Non-Process Area DU surface soil – Dioxin TEQs and BAP TEQs were identified as COCs for PRG development because 97.4 percent of the ELCR is attributed to carcinogenic dioxins/furans expressed as dioxin TEQ (Table 1B). Because the ELCR contribution for individual dioxin/furan congeners was not calculated, all 17 dioxin/furan congeners are considered soil COCs. Table 1C provides a list of the 17 dioxin/furan congeners and their associated toxic equivalency factors (TEF).

3. Process Area DU surface and subsurface soil – Carcinogenic PAHs, expressed as BAP TEQ, are identified as COCs for PRG development because 95.5 percent of the surface soil ELCR is attributed to BAP TEQ (Table 1B). Table 1C presents the seven carcinogenic PAHs and their associated TEFs. In subsurface soil, BAP TEQ (18 percent) and PCP (80 percent) account for a majority of the ELCR; therefore, BAP TEQ and PCP are identified as COCs for PRG development. The HQs for PCP (HQ = 3) and naphthalene (HQ = 1) also exceeded the threshold value of 1.0 (Table 2) and, therefore, both are identified as soil COCs for PRG development. 1,1-biphenyl and 2-methylnaphthalene provided a non-cancer (HQ) risk contribution of greater than or equal to 0.1 and were also retained for PRG development.

3.3 Identification of Groundwater COCs for PRG Development As described in Section 4.2, the designated beneficial use of groundwater at the Site is a potential source of drinking water. Therefore, for site-related contaminants present in groundwater, if the contaminant concentration exceeded a drinking water ARAR (such as MCL), it was identified as a COC for PRG development.

As described in Section 4.3, shallow aquifer groundwater in the Process Area DU and Non-Process Area DU is in direct hydraulic communication with Creosote Branch Creek surface water. Therefore, federal and Louisiana AWQC for protection of aquatic life were identified as ARARs (EPA, 1988) because the designated beneficial use of Creosote Branch Creek includes limited aquatic life and wildlife use. Additionally, because the designated beneficial use also includes secondary contact recreation, a groundwater contaminant was identified as a COC for PRG development if its groundwater concentration exceeded an ELCR greater than or equal to 10-6 or an HI greater than or equal to 0.1, based on the recreational exposure scenario presented in the risk assessment.

As shown in Table 3, many site-related groundwater contaminants do not have chemical-specific ARARs (such as MCLs or federal and Louisiana AWQC). To determine if these contaminants should be identified as COCs for PRG development, other criteria were researched from the following to-be-considered (TBC) information:

• General criteria defined in Louisiana Administrative Code (LAC) 33:IX §1113.6.b. No numerical criteria applicable to groundwater COCs were identified.

• Federal criteria in Quality Criteria for Water (EPA, 1986b). This guidance reports the following for PAHs: “The limited freshwater data base for PAHs, mostly from short-term bioconcentration studies with two compounds, does not permit a statement concerning acute or chronic toxicity.”

• Surface water aquatic protection (Texas Commission Environmental Quality [TCEQ], 2006) screening levels compiled by TCEQ (TCEQ 2014b). The informational sources used by TCEQ to compile the surface water aquatic protection screening levels included: (1) chronic values derived from lethal concentration 50 toxicity testing; (2) chronic values compiled from wastewater permits; (3) Tier II secondary chronic values compiled by the Oak Ridge National Laboratory (Suter and Tsao, 1996); and (4) EPA Region 4


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Water Management Division chronic screening values (EPA Region 4, 2001). Additional information on the TCEQ-compiled ecological screening values is provided in Conducting Ecological Risk Assessments at Remediation Sites in Texas - RG-263 Revised Draft (TCEQ, 2014a).

A majority of the ecological screening values presented in Table 3 were obtained from the TCEQ-compiled ecological screening values. To determine if a COC should be carried forward for PRG development, its maximum observed 2013 groundwater concentration was compared with the values presented in Table 3. COCs with groundwater concentrations higher than one or more of the criteria were retained from PRG development.

Through operation of the current remedy, groundwater is hydraulically contained to prevent contaminant migration to the creek. In the event of no further action (that is, cessation of the current remedy), aquatic ecological receptors could potentially be exposed to contaminants in the groundwater discharging to surface water. Therefore, use of ecological screening values ensures protection of the creek through implementation of future remedies.

Based on the above considerations, the following groundwater COCs were identified for PRG development:

• Process Area – groundwater (shallow aquifer). − Based on exceedance of drinking water MCLs for benzene, ethylbenzene, PCP, and BAP TEQ. The

presence of dioxins/furans in groundwater is currently being evaluated, and the need for a dioxin TEQ PRG will be defined in the draft FS.

− Based on exceedance of AWQC for ethylbenzene and PCP.

− Based on exceedance of the ELCR that is greater than or equal to 10-6 or HI that is greater than or equal to 0.1 for 2-methylnaphthalene, meta & para (m & p) cresols, dibenzofuran, acenaphthene, fluorene, fluoranthene, naphthalene, and pyrene.

− Based on exceedance of TBC criteria for 1, 1-biphenyl, 1-methylnaphthalene, and several low molecular weight PAHs (LPAHs) and HPAHs.

The need for a PRG for dioxin TEQ present in groundwater discharging to surface water is currently being assessed through sampling of groundwater at selected monitoring well locations in the Process Area DU. If it is determined that a PRG is needed, the PRG will be presented in the draft FS.

3.4 COCs Excluded for PRG Development Several compounds that were identified as COCs in the risk assessment reports were not retained as COCs for PRG development in the draft FS (Table 4). These include:

• Soil COCs - Dibenzofuran was excluded because it is co-located with LPAHs.

• Groundwater COCs - Contaminants are co-located (2,4-dimethylphenol, 4-chloroaniline, 4-methylphenol) or are captured by the BAP TEQ (benzo(b)fluoranthene, benzo(k)fluoranthene and indeno(1,2,3-c,d)pyrene) or were infrequently detected (1,1,2,2-tetrachloroethane, 1,1,2-trichloroethane, 1,2-dibromoethane, 1,2-dichloropropane and bromodichloromethane). The infrequently detected contaminants were identified at a single monitoring well (SMW-09) during a 2011 semiannual groundwater sampling event; they were not detected in subsequent monitoring events.

4. Assumptions for RAO and PRG Development The proposed RAOs and PRGs were developed based on media-specific FS scoping discussions described in the following subsections.

4.1 Soil Based on the results of the RI/risk assessment the following information was used to develop RAOs and PRGs for site soil:


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• HPAHS were identified as COCs in the Northern DU based on ecological direct exposure risk for lower trophic level receptors and indirect exposure risk to the deer mouse (Table 1A).

• The primary COCs for human health in the Process Area DU include: BAP TEQ and its associated PAH constituents, dioxin TEQ and its associated dioxins/furan constituents, PCP, and naphthalene (Table 1B and Table 2).

• The primary COCs for human health in the Non-Process Area DU include: dioxin TEQ and its associated dioxins/furan constituents, and BAP TEQ and its associated PAH constituents (Table 1B).

Although the risk assessment identified dibenzofuran as a COC, it was excluded for PRG development because it is co-located with LPAHs and will be addressed through treatment of the primary COCs.

Vadose zone soil PRGs for protection of groundwater and surface water are not needed because this material is co-located with non-aqueous phase liquid (NAPL). Remedial actions that address NAPL will also address soil leachability COCs. Appendix A presents an evaluation that was conducted to assess contaminant leaching from immobile and mobile NAPL-contaminated soil to groundwater. The results of this evaluation were also used to determine if NAPL-contaminated soil should be characterized as source material and as principal threat waste.

4.2 Groundwater Based on the results of the RI/risk assessment, the following information was used to develop groundwater RAOs and PRGs:

• Shallow aquifer groundwater at the ACW site has a beneficial use of Class IIB, which is not a current drinking water source but a future source based on EPA classification guidelines (that is, yield greater than 150 gallons per day and total dissolved solids concentration of less than 10,000 milligrams per liter [mg/L]).

• Based on drinking water MCLs, PRGs are needed for benzene, ethylbenzene, BAP TEQ, and PCP. Groundwater sampling and analysis for dioxins and furans performed at monitoring wells SMW-2 and SMW-9 in October 2014 did not detect 2,3,7,8-tetachlordibenzo-p-dioxin (TCDD) above the laboratory reporting limit of 23 picograms per liter (pg/L). Several other dioxin/furan congeners were detected and dioxin TEQ concentrations of 81.5 pg/L and 15,800 pg/L were reported for the two samples. In calculating the dioxin TEQ, the full reporting limit was used for the non-detect congeners. Additional dioxin/furan sampling and analysis was performed the week of December 1, 2014; and this information will be evaluated further to determine if groundwater PRGs for dioxins/furans should be developed.

• Based on surface water protection ARARs, PRGs are needed for ethylbenzene and PCP.

• Based on aquatic receptor TBC guidelines, PRGs are needed for many of the LPAHs; several of the HPAHs; 1, 1-biphenyl; 1-methylnaphthalene; 2-methylnaphthalene; dibenzofuran; and 3, 4-methylphenol.

• Based on the human health protection (that is, secondary contact recreation), PRGs are needed for several of the LPAHs and HPAHs.

• Because of heavy NAPL contamination, restoration of shallow aquifer groundwater within the Process Area DU to a drinking water beneficial use is not technically practicable from an engineering perspective.

• Remedial action alternatives, or components of a broader sitewide alternative, developed to address NAPL contamination present in the Process Area, Non-Process Area, and western portion of the Tar Mat


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Ash DUs1 are characterized as source control actions. Because source control actions may leave waste in place, attainment of drinking water MCLs would occur at the downgradient boundary of the NAPL source area footprint.

• If necessary, or to complement NAPL source area footprint definition, a technical impracticability zone (TIZ) may be established within the shallow aquifer. The TIZ defines the area/volume where groundwater restoration to drinking water standards will be waived in accordance with the NCP (40 CFR 300.430 [f][1][ii][C][3]). A majority of the TIZ would lie within the Process Area DU.

• A plume management zone (PMZ), which will be larger and enclose the NAPL source area footprint or TIZ, will also be established. The PMZ defines the area/volume where groundwater use restrictions will be established to prevent contaminant mobilization outside the boundaries of the NAPL source area footprint or TIZ.

4.3 Surface Water Per Louisiana Administrative Code 33:IX §1111, the beneficial use of Creosote Branch Creek is presumed to be limited aquatic life and wildlife use and secondary contact recreation (LDEQ, 2014a). Although human contact with surface water and sediment in the vicinity of the ACW site is not expected to occur because of the creek’s degraded condition, steep banks, and variable flow rates that lessen fishing, wading, or boating uses, secondary contact recreation beneficial use was retained for PRG development. Other Creosote Brank Creek Segment 081402 characteristics listed in Receiving Water Characteristics, National Pollution Discharge Elimination System (NPDES) Fact Sheet for City of Winnfield Wastewater Treatment Plant (LDEQ, 2014b) include: (1) a default 7Q102 flow of 0.1 cubic foot per second (cfs) and harmonic mean flow of 1.0 cfs; (2) average hardness of 135 mg/L; and (3) 15th percentile total suspended solids concentration of 7.6 mg/L (ambient monitoring station #2516 – Creosote Branch at the bridge on parish road, 0.6 mile south of U.S. Highway 167 in Winnfield, Louisiana).

Based on an aquatic and wildlife beneficial use, the PRGs for surface water are defined by federal and state numerical AWQC for aquatic organism protection. AWQC for protection of human health through the surface water and organism ingestion and organism-only ingestion pathways are not ARARs because surface water and aquatic organism ingestion are not recognized beneficial uses.

In additional to the numerical AWQC for aquatic organism protection, narrative federal and state general AWQC are also presumed to be ARARs. The state general AWQC (LAC Title 33, Part IX, Subpart 1, §1113) includes criteria for: 1) aesthetics; 2) color; 3) floating, suspended, and settleable solids; 4) taste and odor; 5) toxic substances; 6) oil and grease; 7) foaming or frothing materials; 8) nutrients; 9) turbidity; 10) flow; 11) radioactive substances; 12) biological and aquatic community integrity; and 13) other substances and characteristics (as needed). Groundwater discharging to surface water must not result in an exceedance of these general criteria.

Federal or state AWQC for secondary contact recreation beneficial uses were not identified. Therefore, site-specific criteria were developed using information presented in the Risk Assessment Version 1.1 (CH2M HILL, 2014b).

No surface water COCs were identified in the risk assessment. However, because groundwater and surface water are in hydraulic communication under the baseline condition (that is, the no action alternative), the groundwater COCs shown in Table 3 are those that must be carried into the FS and addressed in the detailed

1 Based on risk characterization of the ash, the Tar Mat Ash DU was not identified to be carried forward into the FS. However, NAPL that likely originates in the Process Area DU extends into the western portion of the Tar Mat Ash DU, in the vicinity of trench sumps S-11 and S-12. Remedial action alternatives developed to address NAPL in the Process Area DU will also address NAPL present in the western portion of the Tar Mat Ash DU. 2 Seven-day, consecutive, low flow with a ten-year return frequency; the lowest stream flow for seven consecutive days that would be expected to occur once in ten years.


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analysis of alternatives so that the preferred alternative satisfies the CERCLA threshold criteria for protection of the environment.

Sampling performed upstream of the ACW site detected the presence of several COCs in surface water and sediment. These occurrences are not site related. The presence of COCs in surface water at background sample locations, and potential exceedances of narrative criteria, were not accounted for in the development of PRGs.

4.4 Non-aqueous Phase Liquid Although a numerical PRG will not be defined for NAPL, its presence has a significant influence on PRG development because of its widespread occurrence in the Process Area DU. NAPL occurrences above and below the water table, and the large NAPL contamination footprint located within 50 feet of the creek, significantly limit COC concentration reductions that can occur through dilution by mixing with infiltrating precipitation and uncontaminated groundwater flow from the upland area. Additionally, the proximity of the NAPL source area’s downgradient boundary to the creek limits the COC concentration reductions that may occur within the aquifer through dispersion/diffusion, adsorption, and biodegradation.

Appendix A provides information that describes the process used to delineate immobile and mobile NAPL-contaminated soil, and the process used to assess whether this material meets the definition of source material, and is principal threat waste or low-level threat waste.

4.5 Institutional Controls Per NCP requirements [40 CFR 300.430 (e)(3)(ii)], it is expected that ICs, either as a standalone alternative or as a component of alternatives employing more aggressive technologies, will be included in the draft FS as appropriate to prevent or limit exposure to hazardous substances. Although the human health risk assessment did not identify VI–indoor air risk exceeding the upper bound of the CERCLA risk management range, all remedial action alternatives developed for the draft FS, with the exception of the no-further-action alternative, will include industrial land use, deep excavation restrictions (such as, no excavation greater than 5 feet and vapor mitigation controls) as common elements.

These controls will require that all future site use be limited to industrial/commercial, and any future site development occurring within the prescribed area include vapor barriers or their equivalent for all new building construction. In addition, land use controls will be developed to restrict deep soil excavation (greater than 5 feet) to protect current and future construction workers from human health risks from exposure to COCs in groundwater. Current and future groundwater use would be limited to monitoring and remediation, with prohibitions on drinking, irrigation, and other industrial uses. Through implementation of these ICs, PRGs for protection of construction workers will not be required.

5. Remedial Action Objectives RAOs are narrative statements that describe what the remedial action is intended to accomplish. They generally identify the COCs, the environmental media, the exposure pathways and receptors to be protected, and the levels of cleanup that need to be achieved by the remedy, based on considerations of current and future land use, and groundwater and surface water beneficial use designations. Future land use for all ACW DUs will be restricted to commercial/industrial purposes using an IC implemented through a future CERCLA decision document.

Based on the findings of the human health and ecological risk assessment, remedial action at the ACW site must address the following exposure pathways, COCs, and environmental media:

• Terrestrial ecological receptor exposure to HPAHs present in Northern DU surface soil

• In the Process Area DU, human health direct contact risk, under industrial land use, associated with exposure to BAP TEQ, dioxin TEQ, PCP, and naphthalene in surface and subsurface soil


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In the Non‐Process Area DU, human health direct contact risk, under industrial land use, associated with exposure to dioxin TEQ present in surface soil

Construction worker direct contact risk associated with exposure to shallow aquifer groundwater COCs (BAP TEQ, PCP, and benzene, ethylbenzene, and xylene) in the Process Area DU (As described in Section 3.5, this exposure pathway will be addressed using a common element IC that prevents excavation at depths below 5 feet. Therefore, an RAO for this exposure pathway is not necessary.)

Under the current remedy, no unacceptable risk is associated with human or ecological exposure to COCs present in Creosote Branch Creek surface water or sediment. In the absence of remedial action, it is presumed that shallow aquifer groundwater discharges to Creosote Branch Creek would result in surface water COC concentrations exceeding AWQC or TBC guidelines. Therefore, it is assumed that remedial action at the ACW site must also address ecological and secondary contact recreational exposure associated with COCs present in shallow aquifer groundwater discharging to Creosote Branch Creek.

The RAOs proposed for inclusion in the draft FS include the following:

1. RAO #1–Protect industrial worker human health in the Process Area and Non‐Process Area Decision Units by minimizing direct contact exposure to the contaminants of concern exceeding the soil and groundwater remediation goals listed in Table 6.

2. RAO #2–Protect terrestrial ecological receptor communities in the Northern Decision Unit from direct contact exposure to the High Molecular Weight Polycyclic Aromatic Hydrocarbons listed in Table 6. The sum of the 95th percentile upper confidence limit concentrations for the listed high molecular weight polycyclic aromatic hydrocarbons should not exceed the remediation goal of 18 milligrams per kilogram in the surface soil of the Northern Decision Unit.

3. RAO #3–Protect aquatic and secondary contact recreational receptors from exposure to the contaminants of concern present in groundwater discharging to Creosote Branch at concentrations exceeding the remediation goals presented in Table 6.

4. RAO #4–Protect the environment by preventing groundwater contaminants of concern from migrating beyond the boundaries of the plume management zone.

RAOs #1 and #2 are needed to address exposure pathways that were identified in the risk assessment as exceeding CERCLA risk management thresholds.

RAO #3 is needed to protect aquatic and recreational receptors that could be exposed to COC concentrations exceeding AWQC or TBC guidelines under the baseline (that is no action) condition.

RAO #4 is needed to comply with EPA expectations, under CERCLA, to contain the NAPL source zone to minimize the further release of contaminants to the surrounding groundwater (EPA, 1993).

6. Preliminary Remediation Goals PRGs define the allowable concentration of COCs in environmental media that are protective of human health and the environment. Therefore, PRGs define the level of media cleanup necessary at the completion of the remedial action. PRGs are defined based on expectations for land, groundwater, and surface water beneficial uses. PRGs are also used to define the area and volume of environmental media to be addressed by a remedial action and to assist in the screening of technologies and development of remedial action alternatives that precede the detailed analysis of alternatives in the FS.

Per the RAOs presented in Section 4, PRGs are needed for:

COCs present in Process Area and Non‐Process Area DUs soil to protect industrial workers

COCs present in Northern DU soil to protect terrestrial ecological receptor communities

011015


• COCs present in Process Area and Non-Process Area shallow aquifer groundwater that lies outside the TIZ

• COCs present in Process Area and Non-Process Area shallow aquifer groundwater inside the TIZ and within the zone of groundwater–surface interaction that are protective of aquatic organism and secondary contact recreation exposure

For the purposes of this evaluation, and based on the existing COC concentrations in Creosote Branch Creek sediments, it is assumed that groundwater and surface water PRGs would also be protective of creek sediment. PRGs for COCs potentially present in surface water runoff are not needed because storm water monitoring has not consistently detected contaminants.

6.1 Industrial Worker Protection – Soil PRGs The approach used to develop PRGs for selected COCs, environmental media, and exposure pathways described above generally follows the process described in the NCP [40 CFR 300.430 (e)(2)(i)]. PRGs for BAP TEQ and dioxin TEQ, and individual soil COCs not included in the BAP TEQ and dioxin TEQ groups, were calculated to span the CERCLA target ELCR range of: 1 x 10-6, 1 x 10-5, and 1 x 10-4, and a non-cancer HI threshold of 1.0. The proposed soil PRGs for industrial worker protection are presented in Table 5.

Because dioxin TEQ risk occurs primarily in the Non-Process Area DU, the dioxin TEQ was developed without considering risk contributions from BAP TEQ or PCP. The industrial soil PRG for dioxin TEQ is presented in Tables 5 and 6. Residual soil concentrations will be documented using post-remedial action samples from areas where soils are remediated.

6.2 Terrestrial Ecological Receptor – Soil The ecological HPAH PRG for Northern DU surface soil is based on a 95-percent upper confidence limit (UCL) EPA Ecological Soil Screening Level of 18 milligrams per kilogram. Post-remediation sampling data will be used to calculate a 95 percent UCL-based EPC for the Northern DU to confirm that the ecological protection PRG was attained.

6.3 Aquatic Organism and Secondary Contact Recreation - Groundwater Discharge to Surface Water

As described in Section 2, federal and state AWQC and TBC guidelines for protection of aquatic receptors and secondary contact recreation exposure in Creosote Branch Creek were identified. These criteria were compiled and the lowest value was determined (see Table 3). The hierarchy used for determination of the groundwater PRG that is protective of surface water, consisted of selecting the lowest value of the federal AWQC and Louisiana AWQC. If an AWQC value was not defined, then the lowest value of the aquatic protection and secondary contact recreation value was selected.

The TBC guidelines were obtained from TCEQ risk-based exposure levels for protection of freshwater aquatic organisms. The TCEQ values are determined from appropriate chronic toxicity data obtained in accordance with procedures in the EPA guidance document entitled Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Life and Their Uses (EPA, 1980). Based on the properties of the chemical (non-persistent, persistent, or bioaccumulative), the lethal concentration 50 values are multiplied by a factor of 0.1 for non-persistent, 0.05 for persistent, and 0.01 for bioaccumulative chemicals. These lookup values are consistent with the defined beneficial use and are based on technical guidance described in Determining Protection Concentration Levels (PCLs) for Surface Water and Sediment, (TCEQ, 2007). Additionally, these values were used in the ACW risk assessment addendum as screening levels for ecological risk in surface water where EPA AWQC were not available. The secondary contact recreation TBC guidelines were calculated using the exposure assumptions described in the Risk Assessment Version 1.1 (CH2M HILL, 2014b).

Additionally, secondary contact based water quality criteria protective of human health were estimated for surface water in the creek under a recreational use scenario for groundwater COCs because it is assumed


011016


that groundwater COCs would discharge to the creek if the current groundwater remediation system is no longer operational. These values are selected when an AWQC value was not available.

PRGs based on the narrative AWQC are not included. These criteria are frequently used in EPA or state administered NPDES permits. Compliance with these criteria is generally assessed visually and/or through special studies. By achieving the numerical PRGs presented in Table 3, it is expected that the narrative criteria will also be met.

7. References CDM. 1992. Remedial Investigation/Feasibility Study for American Creosote Works, Inc. Winnfield, Louisiana.

CH2M HILL. 2014a. Remedial Investigation Report Version No. 1.0 American Creosote Works Site Feasibility Study CERCLIS No. LAD000239814 Winnfield, Louisiana.

CH2M HILL. 2014b. Risk Assessment, American Creosote Works Superfund Site Feasibility Study, Winnfield, Louisiana. Version 1.1. Contract No. EP-W-06-021.

CH2M HILL. 2014c. Risk Assessment Addendum Report American Creosote Works Site Feasibility Study, Winnfield, Louisiana. Version 1.0. Contract No. EP-W-06-021.

CH2M HILL. 2014d. American Creosote Works Superfund Site Decision Unit Preliminary Risk Evaluation by Media (Soil, Sediment and Surface Water).

CH2M HILL. 2014e. Draft Technical Memorandum Ecological Risk-Based Soil Removal Strategy Approach for the Northern Decision Unit. September 19.

Louisiana Department of Environmental Quality (LDEQ). 2014a. Title 33 Environmental Quality Part IX. Water Quality Subpart 1. Water Pollution Control.

Louisiana Department of Environmental Quality (LDEQ). 2014b. National Pollution Discharge Elimination System (NPDES) Fact Sheet for City of Winnfield Wastewater Treatment Plant.

Oak Ridge National Laboratory. 2014. Ecological Benchmark Tool. Available at: http://rais.ornl.gov/tools/eco_search.php

Suter, G.W. and C. L. Tsao. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision.

Texas Commission Environmental Quality (TCEQ). 2006. Update to Guidance for Conducting Ecological Risk Assessments at Remediation Sites in Texas RG-263 (Revised). Remediation Division. January. http://www.tceq.state.tx.us/assets/public/remediation/eco/0106eragupdate.pdf

Texas Commission Environmental Quality (TCEQ). 2007. Determining Protection Concentration Levels (PCLs) for Surface Water and Sediment, (TCEQ RG-366/TRRP-24.

Texas Commission Environmental Quality (TCEQ). 2014a. Conducting Ecological Risk Assessments at Remediation Sites in Texas - RG-263 Revised Draft.

Texas Commission Environmental Quality (TCEQ). 2014b. Ecological Benchmarks for Water, Update to Guidance for Conducting Ecological Risk Assessments.

U.S. Environmental Protection Agency (EPA). 1980. Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Life and Their Uses. EPA 822-R-85-100.

U.S. Environmental Protection Agency (EPA). 1986a. Guidelines for Ground-Water Classification under the EPA Ground-Water Protection Strategy.

U.S. Environmental Protection Agency (EPA). 1986b. Quality Criteria for Water. EPA 440/5-86-001.

U.S. Environmental Protection Agency (EPA). 1988. CERCLA Compliance with Other Laws Manual: Interim Final, EPA/540/G-89/006.


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http://rais.ornl.gov/tools/eco_search.php

http://rais.ornl.gov/tools/eco_search.php

http://www.tceq.state.tx.us/assets/public/remediation/eco/0106eragupdate.pdf

http://www.tceq.state.tx.us/assets/public/remediation/eco/0106eragupdate.pdf


U.S. Environmental Protection Agency (EPA). 1993. Guidance for Evaluating the Technical Impractability of Ground-Water Restoration Interim-Final. EPA Directive 9234.2-25.

U.S. Environmental Protection Agency (EPA). 2007. Ecological Soil Screening Levels for Polycyclic Aromatic Hydrocarbons (PAHs). Interim Final. OSWER Directive 9285.7-78. June.

U.S. Environmental Protection Agency (EPA). 2012. EPA’s Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments, Volume 1. (Final Non-Cancer Dioxin Reassessment.) www.epa.gov/iris

U.S. Environmental Protection Agency (EPA). 2013. Regional Screening Levels (RSL) for Chemical Contaminants at Superfund Sites User’s Guide. November.

U.S. Environmental Protection Agency (EPA). 2014a. National Recommended Water Quality Criteria. http://water.epa.gov/scitech/swguidance/standards/criteria/current/index.cfm#altable

U.S. Environmental Protection Agency (EPA). 2014b. EPA Regional Screening Level Table.

U.S. Environmental Protection Agency (EPA), Region 4. 2001. Supplemental Guidance to RAGS: Region 4 Bulletins, Ecological Risk Assessment. Originally published November 1995. Available online at: http://www.epa.gov/region4/waste/ots/ecolbul.htm

Van den Berg, M; Birnbaum, LS; Denison, M; et al. 2006. “The 2005 World Health Organization Re-evaluation of Human and Mammalian Toxic Equivalency Factors for Dioxins and Dioxin-Like Compounds.” Toxicological Sciences 93(2):223−241.


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http://www.epa.gov/iris

http://www.epa.gov/iris

http://water.epa.gov/scitech/swguidance/standards/criteria/current/index.cfm%23altable

http://water.epa.gov/scitech/swguidance/standards/criteria/current/index.cfm%23altable

http://www.epa.gov/region4/waste/ots/ecolbul.htm

http://www.epa.gov/region4/waste/ots/ecolbul.htm


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Tables

011020

TABLES

ACW SUPERFUND SITE FEASIBILITY STUDY REMEDIAL ACTION OBJECTIVES AND PRELIMINARY REMEDIAL GOALS_TABLES EN0119151011SPB


011021

TABLE 1AFood Web Risk Calculations for PAHs ‐‐ Terrestrial Mammals, Northern Decision UnitAmerican Creosote Works, Winnfield, Louisiana

BAF mg/kg dw BAF mg/kg dw BAF mg/kg dw NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL

PAHs, Low Molecular Weight2‐Methylnaphthalene 0.008 0.0002 0.200 0.002 1.580 0.013 0.00 0.00 50.00 150.00 0.056 0.00 0.00 0.0000 0.00 0.00 0.000 0.00 0.00 0.000 0.00 0.00

Acenaphthene 0.088 0.0005 0.300 0.027 Regressiond 0.031 0.00 0.00 50.00 150.00 0.236 0.00 0.00 0.0003 0.00 0.00 0.001 0.00 0.00 0.000 0.00 0.00Acenaphthylene 0.993 0.0050 0.220 0.218 Regression 0.317 0.00 0.00 50.00 150.00 2.219 0.04 0.01 0.002 0.00 0.00 0.008 0.00 0.00 0.001 0.00 0.00Anthracene 0.297 0.0001 0.320 0.095 Regression 0.145 0.00 0.00 50.00 150.00 0.954 0.02 0.01 0.001 0.00 0.00 0.002 0.00 0.00 0.000 0.00 0.00Fluorene 0.047 0.0050 0.200 0.009 Regression 0.053 0.00 0.00 50.00 150.00 0.267 0.01 0.00 0.000 0.00 0.00 0.001 0.00 0.00 0.000 0.00 0.00Naphthalene 0.041 0.0008 0.210 0.009 12.200 0.504 0.00 0.00 50.00 150.00 1.828 0.04 0.01 0.000 0.00 0.00 0.000 0.00 0.00 0.000 0.00 0.00Phenanthrene 0.173 0.0050 0.280 0.049 Regression 0.286 0.00 0.00 50.00 150.00 1.273 0.03 0.01 0.001 0.00 0.00 0.002 0.00 0.00 0.000 0.00 0.00

PAHs, High Molecular WeightBenzo(a)anthracene 3.847 0.0001 0.270 1.039 Regression 0.149 0.00 0.00 1.00 10.00 5.453 5.5 0.5 0.010 0.01 0.00 0.030 0.03 0.00 0.002 0.00 0.00Benzo(a)pyrene 6.280 0.0002 0.340 2.135 Regression 0.763 0.00 0.00 1.00 10.00 12.572 12.6 1.3 0.020 0.02 0.00 0.049 0.05 0.00 0.003 0.00 0.00Benzo(b)fluoranthene 14.306 0.0001 0.210 3.004 0.310 4.435 0.00 0.00 1.00 10.00 30.422 30.4 3.0 0.028 0.03 0.00 0.112 0.11 0.01 0.009 0.01 0.00Benzo(g,h,i)perylene 9.652 0.0007 0.150 1.448 Regression 5.758 0.00 0.00 1.00 10.00 27.892 27.9 2.8 0.013 0.01 0.00 0.075 0.08 0.01 0.008 0.01 0.00Benzo(k)fluoranthene 5.694 0.0001 0.210 1.196 Regression 0.515 0.00 0.00 1.00 10.00 7.693 7.7 0.8 0.011 0.01 0.00 0.044 0.04 0.00 0.003 0.00 0.00Chrysene 7.333 0.0001 0.440 3.227 Regression 0.218 0.00 0.00 1.00 10.00 15.351 15.4 1.5 0.030 0.03 0.00 0.057 0.06 0.01 0.004 0.00 0.00Dibenz(a,h)anthracene 1.285 0.0002 0.490 0.630 0.130 0.167 0.00 0.00 1.00 10.00 3.414 3.4 0.3 0.006 0.01 0.00 0.010 0.01 0.00 0.001 0.00 0.00Fluoranthene 7.117 0.0050 0.370 2.633 0.500 3.559 0.00 0.00 1.00 10.00 24.686 24.7 2.5 0.024 0.02 0.00 0.056 0.06 0.01 0.006 0.01 0.00Indeno(1,2,3‐cd)pyrene 4.316 0.0002 0.410 1.770 0.110 0.475 0.00 0.00 1.00 10.00 9.722 9.7 1.0 0.016 0.02 0.00 0.034 0.03 0.00 0.002 0.00 0.00Pyrene 6.542 0.0050 0.390 2.551 0.720 4.710 0.00 0.00 1.00 10.00 28.325 28.3 2.8 0.024 0.02 0.00 0.052 0.05 0.01 0.007 0.01 0.00

Dietary Intake Equation

Componente Deer Mouse

Nine‐banded

Armadillo Mink Red Fox Notes:

DI Dietary intake for chemical (see above)

FIR 0.165 0.051 0.071 0.052 Food ingestion rate (kg/day dry weight)

FCxmammal Concentration of chemical x in small mammals (see above)

PDFmammal 0% 0% 91% 87% Proportion of diet composed of small mammals (percent)

FCxinvert Concentration of chemical x in soil invertebrates (see above)PDFinvert 53% 100% 0% 3% Proportion of diet composed of soil invertebrates (percent)FCxplant Concentration of chemical x in terrestrial plants (see above) d See table of values to the left to use with the following BCF regression equation:PDFplant 45% 0% 0% 7% Proportion of diet composed of terrestrial plants (percent) ln (Conc) = B1*(ln[Site Specific Soil/Sediment Concentration]) + B0

Scxsoil Concentration of chemical x in soil (see above) e See text for dietary intake equation and description.PDsoil 2.0% 0.0% 9.4% 2.8% Proportion of diet composed of soil (percent) f Area use factor (AUF); assumes receptors spend 100 percent of time feeding on site.WIR 0.146 0.083 0.101 0.085 Water ingestion rate (liter/day) Bolded and Shaded Hazard Quotients > 1.0WCx Concentration of chemical x in water (mg/L) "‐‐" = no dataBW 0.021 5.500 0.852 4.535 Body weight (kilogram wet weight) AUF = area use factorAUFf 1.000 1.000 1.000 1.000 Area Use Factor (100% site use assumed) BAF = bioaccumulation factor

BCF = bioconcentration factorRegression Values for BCF Concentration Equation LOAEL = lowest observed adverse effect level

B0 B1 mg/kg/day = milligram per kilogram per daySoil‐to‐Plant mg/kg dw = milligram per kilogram dry weightAcenaphthene ‐5.562 ‐0.856 mg/L = milligram per literAcenaphthylene ‐1.144 0.791 NA = not availableAnthracene ‐0.989 0.778 NOAEL = no observed adverse effect levelFluorene ‐5.562 ‐0.856 PAH = polycyclic aromatic hydrocarbonPhenanthrene ‐0.167 0.620 TRV = toxicity reference valueBenzo(a)anthracene ‐2.708 0.594Benzo(a)pyrene ‐2.062 0.975Benzo(g,h,i)perylene ‐0.931 1.183Benzo(k)fluoranthene ‐2.158 0.860Chrysene ‐2.708 0.594

Description

Chemical‐specific

Chemical‐specific b Surface water concentrations represent the maximum value in all samples (branches andpond).

Chemical‐specificc A soil‐to‐small mammal BAF of zero was assumed because bioaccumulation of PAHs is not significant in small mammals (EPA, 2007).

Chemical‐specific

Chemical‐specific

Chemical‐specific a Soil concentrations represent the 95% upper confidence limit (UCL) value in this decision unit (DU).

Nine‐banded Armadillo Mink Red FoxSoil Invertebrates Terrestrial Plants Small Mammalsc

Dietary Intake

(mg/kg/day)

Hazard QuotientsDietary Intake

(mg/kg/day)

Hazard QuotientsDeer Mouse

Dietary

Intake

(mg/kg/day)

Hazard Quotients Dietary

Intake

(mg/kg/day)

Hazard QuotientsDetected Bioaccumulative

Constituent

Soil

(mg/kg dw)a

Surface

Water

(mg/L)b

Prey Item Tissue Mammal TRVs

(mg/kg/day)

ACW_RA_ADDENDUM_REPORT_TABLE Table 1A‐ECO NDUES031714032732SPB PAGE 1 OF 1

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011023

TABLE 1BSummary of the Decision Unit Industrial/Commercial Worker Risk Screening ResultsAmerican Creosote Works Superfund Site

Dioxin TEQ

EPC ELCR

BAP TEQ

EPC ELCR

Total PREa

(ELCR)

Exceeds Upper

Bound of

CERCLA Risk

Range

18 1.0E‐06 0.21 1.0E‐06

Northern Surface Soil (0 to 1 feet bgs) 175 9.7E‐06 17.7 8.4E‐05 9.4E‐05 No

Subsurface Soil (1 to 10 feet bgs) NA NA 2.0 9.3E‐06 9.3E‐06 No

Non‐Process Area Surface Soil (0 to 1 feet bgs) 14,634 8.1E‐04 4.5 2.2E‐05 8.3E‐04 Yes


Process Area Surface Soil (0 to 1 feet bgs) 237 1.3E‐05 59.1 2.8E‐04 2.9E‐04 Yes

Subsurface Soil (1 to 10 feet bgs) NA NA 296 1.4E‐03 1.4E‐03 Yes

Southern Surface Soil (0 to 1 feet bgs) 288 1.6E‐05 4.9 2.3E‐05 3.9E‐05 No


Western Surface Soil (0 to 1 feet bgs) 200 1.1E‐05 3.9 1.8E‐05 2.9E‐05 No

Tar Mat Subsurface Soil (1 to 10 feet bgs) 285 1.6E‐05 0.2 1.1E‐06 1.7E‐05 No

RSLs Sediment (Industrial)b 18 0.21

Fire Water Pond Sediment 80 4.4E‐06 0.4 2.1E‐06 6.5E‐06 No

North Creosote Branch Sediment 61 3.4E‐06 3.3 1.6E‐05 1.9E‐05 No

West Creosote Branch Sediment 8 4.3E‐07 0.4 1.9E‐06 2.3E‐06 No

Background Values

Background Surface Soil 32 NA 0.4 NA NA

Subsurface Soil NA NA 0.4 NA NA

Surface Water NA NA 21.1 NA NA

Sediment 11 NA 0.9 NA NA

Notes:

Identifies Decision Units and media carried forward to feasibility study based on exceedance of upper bound CERCLA risk range.a PRE = Preliminary Risk Evaluation = (Dioxin TEQ or BAP TEQ/ Industrial RSL)*10^‐6 for carcinogensb PRE was calculated for sediment using the soil Industrial RSL value of 18 ng/kg for dioxins and 0.21 mg/kg for PAHs. Surface water criteria were not available for industrial workers for a PRE calculation.µg/L = microgram per literBAP‐TEQ = benzo(a)pyrene toxicity equivalent concentrationbgs = below ground surfaceCERCLA = Comprehensive Environmental Response, Compensation, and Liability Actdioxin TEQ = 2,3,7,8‐TCDD toxicity equivalent concentrationDU = Decision UnitELCR = excess lifetime cancer risk EPC = exposure point concentration kg = kilogrammg = milligram

NA = not applicableng = nanogram

Dioxins (ng/kg) PAHs (mg/kg) Quantitative RA

Risk‐based Screening Level (Industrial)bDecision Unit Medium

011024

TABLE 1CToxic Equivalence Factors Used for the Calculation of 2,3,7,8‐Tetrachlorodibenzo‐p‐dioxin and Total Benzo(a)pyrene Toxicity EquivalentsAmerican Creosote Works, Winnfield, Louisiana

Dioxin/Furan CongenerToxic Equivalence

Factors (TEF)a Carcinogenic PAHs TEFb

1,2,3,4,6,7,8‐HEPTACHLORODIBENZOFURAN 0.01 BENZO(a)ANTHRACENE 0.1

1,2,3,4,6,7,8‐HEPTACHLORODIBENZO‐p‐DIOXIN 0.01 BENZO(a)PYRENE 1

1,2,3,4,7,8,9‐HEPTACHLORODIBENZOFURAN 0.01 BENZO(b)FLUORANTHENE 0.1

1,2,3,4,7,8‐HEXACHLORODIBENZOFURAN 0.1 BENZO(k)FLUORANTHENE 0.01

1,2,3,4,7,8‐HEXACHLORODIBENZO‐p‐DIOXIN 0.1 CHRYSENE 0.001

1,2,3,6,7,8‐HEXACHLORODIBENZOFURAN 0.1 DIBENZ(a,h)ANTHRACENE 1

1,2,3,6,7,8‐HEXACHLORODIBENZO‐P‐DIOXIN 0.1 INDENO(1,2,3‐c,d)PYRENE 0.1

1,2,3,7,8,9‐HEXACHLORODIBENZOFURAN 0.1

1,2,3,7,8,9‐HEXACHLORODIBENZO‐P‐DIOXIN 0.1

1,2,3,7,8‐PENTACHLORODIBENZOFURAN 0.03

1,2,3,7,8‐PENTACHLORODIBENZO‐p‐DIOXIN 1

2,3,4,6,7,8‐HEXACHLORODIBENZOFURAN 0.1

2,3,4,7,8‐PENTACHLORODIBENZOFURAN 0.3

2,3,7,8‐TETRACHLORODIBENZOFURAN 0.1

2,3,7,8‐TETRACHLORODIBENZO‐p‐DIOXIN 1

OCTACHLORODIBENZOFURAN 0.0003

OCTACHLORODIBENZO‐p‐DIOXIN 0.0003

Notes:

BAP = benzo(a)pyrenePAH = polycyclic aromatic hydrocarbonTEF = toxic equivalence factorTCDD = 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin

a 2,3,7,8‐TCDD TEFs were developed by the World Health Organization and published in The 2005 World Health Organization Reevaluation of Human and Mammalian Toxic

Equivalency Factors for Dioxins and Dioxin‐Like Compounds (Van den Berg et al., 2006).b BAP TEFs were obtained from EPA’s regional screening levels (RSL) for Chemical Contaminants at Superfund Sites User’s Guide (EPA, 2013).

ACW SUPERFUND SITE FEASIBILITY STUDY REMEDIAL ACTION OBJECTIVES AND PRELIMINARY REMEDIAL GOALS_TABLE 1CEN0119151011SPB

PAGE 1 OF 1

011025

TABLE 2Summary of Human Health Risks and Chemicals of ConcernAmerican Creosote Works, Winnfield, Louisiana

Receptor Exposure Area Medium Exposure Route ELCR HI Chemicals of Concerna

Industrial/ Soil (Process Area DU) Surface Soil

Commercial (0‐1 foot bgs)Worker Subsurface Soil

(1‐10 feet bgs)Groundwater Shallow Total 2E‐01 262

(Process Area and Groundwater

Non‐Process DUs) (Process Area andNon‐Process DUs)

Construction Soil (Process Area DU) Surface SoilWorker (0‐1 foot bgs)

Subsurface Soil

(1‐10 feet bgs)Groundwater Shallow

(Process Area and Groundwater

Non‐Process DUs) (Process Area and Non‐Process DUs)Receptor Total 5E‐03 78

Notes:

HI = hazard index

c Noncarcinogenic PAHS include: acenaphthene, acenaphthylene, anthacene, fluoranthene, fluoranthene, phenanthrene, and pyrene

a COCs are contaminants of potential concern with an individual ELCR greater than 1E‐06, contributing to a receptor total ELCR greater than the upper end of EPA's acceptable risk range of 1E‐04, and/or those COPCs with an individual hazard quotient greater than 0.1, contributing to a receptor target‐organ specific HI greater than 1.0. b BAP TEQ includes: benzo(a)anthacene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene, debenz(a,h)anthacene, and indeno(1,2,3‐cd)pyrene

BAP TEQ = benzo(a)pyrene toxicity equivalentbgs = below ground surface

ELCR = excess lifetime cancer riskCOC = chemical of concern

Total 4E‐03 11 fluoranthene, PCP, naphthalene, total BAP TEQ

Total 2E‐04 6 total dioxin TEQ, naphthalene, PCP, total BaP TEQ

Total 2E‐04 7 2‐methylnaphthalene, PCP, total BAP TEQ, naphthalene

noncarcinogenic PAHs c, methylphenols, 1,1‐biphenyl, 1,1,2,2‐tetrachloroethane, 1,1,2‐trichloroethane, 1,2‐dibromoethane, 1,2‐dichloropropane, bromodichloromethane, PCP, total BAP TEQ, benzene, and ethylbenzene

Total 2E‐03 3.5 total dioxin TEQ, 1,1‐biphenyl, PCP, total BAP TEQ

Total 2E‐03 4 2‐methylnaphthalene, PCP, total BAP TEQ, 1,1'‐biphenyl, naphthalene

ACW SUPERFUND SITE FEASIBILITY STUDY REMEDIAL ACTION OBJECTIVES AND PRELIMINARY REMEDIAL GOALS_TABLE 2EN0119151011SPB PAGE 1 OF 1

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011027

TABLE 3

American Creosote Works ‐ Winnfield, LA

COCs

Highest 2011/2012

Groundwater

Concentration at Recovery

Wells (µg/L)

Highest 2013 Groundwater

Concentration at Monitoring

Wells (µg/L)

Drinking Water MCL

(µg/L)

Federal AWQC ‐ Aquatic

Organism Protection

(µg/L)a

Louisiana State AWQC ‐

Aquatic Organism

Protection (µg/L)b

Ecological Screening

Value (µg/L)cSecondary Contact

Recreation (µg/L)dProposed PRGe

(µg/L)

Benzene Not Tested 458 5 NS 1,125 130 4,706 1,125

Ethylbenzene Not Tested 3,300 700 NS 1,600 1,090 19,755 1,600

PCP 367 2,530 1 15 (pH: 7.8)c NS 2.1 26.9 15

BAP TEQ 4,858 1,570 0.2 NS NS NC 0.25 0.25

Dioxin TEQ Not Tested 0.016 NS NS NS NS 6.6E‐06 Pendingh

2‐Methylnaphthalene 77,300 NR NS NS NS 63 NC 63

3&4‐Methylphenol (m&p‐Cresol) 3,240 NR NS NS NS 272 99,832 272

Dibenzofuran NR NR NS NS NS 94 109 94

Acenaphthene 69,700 5,460 NS NS NS 23 8,073 23

Fluorene 75,400 5,590 NS NS NS 11 3,917 11

Fluoranthene 101,000 9,430 NS NS NS 6.2 3,917 6.2

Naphthalene 321,000 19,800 NS NS NS 250 5,689 250

Pyrene 66,700 5,790 NS NS NS 7.0 1,279 7.0

1,1‐biphenyl 15,500 995 NS NS NS 14 10,747 14

1‐Methylnaphthalene 51,300 NR NS NS NS 2.1 3,243 2.1

Acenaphthylene 2,860 313 NS NS NS NS 7,731 7,731

Anthracene 30,500 2,810 NS NS NS 0.3 21,058 0.3

Phenanthrene 215,000 18,100 NS NS NS 30 20,741 30

Benzo(a)anthracene 18,500 1,890 NS NS NS 34.6 4,706 35

Benzo(a)pyrene 9,200 1,200 NS NS NS 0.014 0.83 0.014

Chrysene 17,100 1,800 NS NS NS 7.0 NC 7.0

Dibenz(a,h)anthracene 1,710 43 NS NS NS 5.0 NC 5.0

Xylenes Not Tested 6,500 NS NS NS 1,340 61,190 1,340

2,4‐Dimethylphenolf Not Tested 10,200 NS NS NS 105 NS NC

4‐Chloroaniline Not Detected Not Detected NS NS NS NS NS NC

4‐Methylphenol (p‐cresol) Not Tested 8,730 NS NS NS NS NS NC

Benzo(b)fluoranthenef 10,400 1,230 NS NS NS NS NC NC

Benzo(k)fluoranthenef 6,790 915 NS NS NS NS NC NC

Indeno(1,2,3‐c,d)pyrenef 3,840 445 NS NS NS NS NC NC

1,1,2,2‐Tetrachloroethaneg Not Tested Not Tested NS NS 466 466 NS NC

1,1,2‐Trichloroethaneg Not Tested Not Tested NS NS NS 900 NS NC

1,2‐Dibromoethaneg Not Tested Not Tested NS NS NS NS NS NC

1,2‐Dichloropropaneg Not Tested Not Tested NS NS NS 1,870 NS NC

Bromodichloromethaneg Not Tested Not Tested NS NS NS 2,160 NS NC

Notes:

b Table 1, Freshwater Chronic Numerical Criteria for Specific Toxic Substances LAC Title 33, Part IX, Subpart 1 (April 2014)

d Site‐specific calculated value based on lowest value of excess lifetime cancer risk of 1 x 10‐4 or hazard quotient of 1.0

PRGS were not developed for co‐contaminants but they will be addressed through treatment of the primary COCs

µg/L = microgram per literARAR = applicable or relevant and appropriate requirement

AWQC = ambient water quality criteria COC = contaminant of concernELCR = excess lifetime cancer riskLDEQ = Louisiana Department of Environmental QualityMCL = maximum contaminant levelNC = not calculatedNR = not reportedNS = not specified

Groundwater Discharge to Surface Water ARARS and To Be Considered Guidance Used for Preliminary Remediation Goals

Bold values indicate proposed PRG and its origin category

Contaminants with Concentrations Above MCLs or AWQC

Contaminants with Concentrations Corresponding to an ELCR ≥ 10‐6 or HQ ≥ 0.1

Contaminants with Concentrations Above TBC

Contaminants Not Carried Forward for PRGs due to Co‐location, Infrequent Detection or Capture by Group Based PRG

e Priority for selection of PRG: Lower of Federal and State AWQC, then lower of Ecological Screening and Secondary Contact Recreation per Section 1.4, CERCLA Compliance with Other Laws Manual:

Interim Final , EPA/540/G‐89/006, 1988.

c Texas Commission on Environmental Quality (TCEQ); http://www.tceq.state.tx.us/assets/public/remediation/eco/0106eragupdate.pdf

a Environmental Protection Agency (EPA) National Recommended Water Quality Criteria (EPA, 2014a)

h The presence of dioxin TEQ in groundwater is currently being evaluated and the need for a PRG will be determined. The concentration shown based on Oct 2014 sampling at: SMW‐2 and SMW‐9

f Co‐contaminants. The risk assessments identified these compounds as having a ELCR greater than 1x10‐6 or HQ of 0.1.


011028


011029

TABLE 4COCs Retained for PRG DevelopmentAmerican Creosote Works, Winnfield, Louisiana

Soil Groundwater Soil Groundwater Soil Groundwater Soil Groundwater

1,1‐Biphenyl 2,4‐Dimethylphenol Dibenzofuran 2,4‐Dimethylphenol None 4‐Chloroaniline None benzo(b)fluoranthened

2‐methylnaphthalene 4‐Chloroaniline 4‐Methylphenol (p‐cresol) 1,1,2,2‐tetrachloroethane benzo(k)fluoranthened

Dibenzofuran 4‐Methylphenol (p‐cresol) Acenaphthene 1,1,2‐trichloroethane indeno(1,2,3‐cd)pyrened

Pentachlorophenol 1‐methylnaphthalene Fluorene 1,1,2‐trichloroethaneTotal BAP TEQ b 2‐methylnaphthalene 1,2‐dibromoethane

Naphthalene Acenaphthene 1,2‐dichloropropaneTotal Dioxin TEQ Benzene bromodichloromethane

3,4 methylphenol (m & p cresols)

Dibenzofuran

Ethylbenzene

Fluoranthene

Fluorene

Naphthalene

Pentachlorphenol

Pyrene

BAP TEQb

Dioxin TEQ c

Xylenes

Acenaphthylene

Anthracene

Phenanthrene

1,1‐Biphenyl

1,1,2,2‐tetrachloroethane1,1,2‐trichloroethane1,2‐dibromoethane

1,2‐dichloropropanebromodichloromethane

Notes:

A COC identified with bold font indicates it was carried forward for PRG development

Industrial Land Use Risk Assessment COCsa COCs Excluded from PRG Development

Due to Infrequent Detection

COCs Excluded from PRG Development Based on Nominal Risk

Contribution (ELCR ≤1 x 10‐5 or HI≤ 1.0)

COCs Removed from PRG Development

Due to Co‐Location

a COCs are contaminants of potential concern under an industrial exposure scenario, with individual ELCRs greater than or equal to 1E‐06, contributing to a receptor total ELCR greater than the upper end of EPA's acceptable risk range of 1E‐04, and/or those COPCs with an individual hazard quotient greater than or equal to 0.1, contributing to a receptor target‐organ specific HI greater than 1.


011030


011031

Soil COCs

Max. Detected

Concentration in

2008 or 2013 Samples

(mg/kg)

Background

Concentrations

(mg/kg)

Target Cumulative

Risk: 1x10‐6Target Cumulative

Risk: 1x10‐5Target Cumulative

Risk: 1x10‐4Process Area DU

(mg/kg)

Non‐Process Area

DU (mg/kg)

Northern DU

(mg/kg)

Naphthalene 6,400 NA 17 170 1,700 290b NA 290 NA NA

Pentachlorophenol 42,000 NA 4 40 400 NA NA 400 NA NA

1,1‐Biphenyl 440 NA NC NC NC 200 NA 200 NA NA

2‐Methylnaphthalene 2,600 NA NC NC NC 3,000 NA 3,000 NA NA

BAP TEQ 296 0.43 3b 3b 3b NA NA 3.0 3 NA

Dioxin TEQ 0.015 0.000032 NA NA NA 0.00073e NA 0.00073 0.00073 NA

High Molecular Weight PAHs f 108.8 (Northern DU)

NA NA NA NA NA 18 NA NA 18 c

Notes:a PRGs for protection of human health selected from EPA regional screening level tables (EPA, 2014b).b Values from LDEQ RECAP guidance (Table 2, MO1 for Naphthalene; RECAP‐Appendix D Anthropogenic Background Based value for BAP TEQ).

C = cancerCOC = contaminant of concernDioxin TEQ = 2,3,7,8‐TCDD toxicity equivalent concentrationDU = decision unit

HQ = hazard quotientLDEQ = Louisiana Department of Environmental Qualitymg/kg = milligram per kilogramNA = not applicable NC = noncancerPAH = polycyclic aromatic hydrocarbonPRG = preliminary remediation goal

Contaminants with Concentrations Corresponding to an ELCR ≥ 10‐6 or HQ ≥ 0.1

Contaminants with Concentrations Corresponding to an Ecological HQ ≥ 1

TABLE 5Preliminary Remediation Goals for SoilAmerican Creosote Works ‐ Winnfield, Louisiana

Human Health PRGs (Industrial; mg/kg)a

ELCR Based PRGs

Non‐cancer Target

Risk = 1.0

Ecological PRG

(mg/kg)c

Proposed Soil PRGs

ELCR = excess lifetime cancer risk

BAP TEQ = benzo(a)pyrene toxicity equivalent

e Final Non‐Cancer Dioxin Reassessment (EPA, 2012); EPA Superfund, Non‐Cancer Toxicity Value for Dioxin at CERCLA/RCRA Cleanups, Questions and Answers ‐ Use of 2,3,7,8‐TCDD Reference Dose, released 2/12/2012.f Ecological PRGs were not developed for individual high molecular weight PAH compounds but are included in the total high molecular weight PRG calculation. The individual high molecular weight PAHS include: benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenz(a,h)anthracene, fluoranthene, indeno(1,2,3‐c,d)pyrene, and pyrene.

c DU‐wide "hotspot" removal approach for high molecular weight total PAHs (direct exposure for lower trophic receptors) and individual PAHs (indirect [food chain] exposure for upper trophic level receptors) per Draft Technical Memorandum Ecological Risk‐Based Soil Removal Strategy Approach for the Northern Decision Unit (CH2M HILL, 2014e).


011032


011033

Contaminant of Concern Units Northern DUNon‐Process Area

DU

Process Area

DUPRG Basis

High Molecular Weight PAHs a mg/kg 18 NA NA Ecological Receptor at HQ=11,1‐Biphenyl mg/kg NA NA 200 Human Health at HQ = 12‐Methylnaphthalene mg/kg NA NA 3,000 Human Health at HQ = 1BAP TEQ mg/kg NA 3.0 3.0 Human Health at ELCR = 1 x 10‐4

Dioxin TEQ mg/kg NA 0.00073 0.00073 Human Health at HQ = 1Naphthalene mg/kg NA NA 290 Human Health at HQ = 1Pentachlorophenol mg/kg NA NA 400 Human Health at ELCR = 1 x 10‐4

1,1‐biphenyl µg/L NA Ecological Screening Value e

1‐Methylnaphthalene µg/L NA Ecological Screening Value e

2‐Methylnaphthalene µg/L NA Ecological Screening Value e

3&4‐Methylphenol (m&p‐Cresol) µg/L NA Ecological Screening Value e

Acenaphthene µg/L NA Ecological Screening Value e

Acenaphthylene µg/L NA Site‐specific Secondary Contact Recreationd

Anthracene µg/L NA Ecological Screening Valuee

BAP TEQ µg/L NA Site‐specific Secondary Contact Recreationd

Benzene µg/L NA Louisiana AWQC ‐ Aquatic Organism Protectionb

Benzo(a)anthracene µg/L NA Ecological Screening Valuee

Benzo(a)pyrene µg/L NA Ecological Screening Valuee

Chrysene µg/L NA Ecological Screening Valuee

Dibenz(a,h)anthracene µg/L NA Ecological Screening Valuee

Dibenzofuran µg/L NA Ecological Screening Valuee

Dioxin TEQ µg/L NA

Ethylbenzene µg/L NA Louisiana AWQC ‐ Aquatic Organism Protectionb

Fluoranthene µg/L NA Ecological Screening Valuee

Naphthalene µg/L NA Ecological Screening Valuee

Pentachlorophenol µg/L NA Federal AWQC ‐ Aquatic Organism Protectionc

Phenanthrene µg/L NA Ecological Screening Valuee

Pyrene µg/L NA Ecological Screening Valuee

Xylenes µg/L NA Ecological Screening Valuee

Notes:

b Reference: Table 1, Freshwater Chronic Numerical Criteria for Specific Toxic Substances Louisiana Administrative Code Title 33, Part IX, Subpart 1 (April 2014)

d Reference: Site‐specific calculated value based on lowest value of excess lifetime cancer risk of 1 x 10 ‐4 or hazard quotient of 1.0e Reference: Texas Commission on Environmental Quality, http://www.tceq.state.tx.us/assets/public/remediation/eco/0106eragupdate.pdff Non‐Process Area and Process Area Decision Units lie in the same geographic portion of the shallow aquifer; therefore, the PRGs are the same. g A determination on need for a Dioxin TEQ PRG will be made following evaluation of the December 2015 sampling results. µg/L = microgram per literAWQC = ambient water quality criteria BAP = benzo(a)pyreneDU = Decision UnitELCR = excess lifetime cancer riskHQ = hazard quotientmg/kg = milligram per kilogramNA = not applicablePAH = polycyclic aromatic hydrocarbonPRG = preliminary remediation goalTEQ = toxicity equivalent

94

Pendingg

1,600

6.2

14

2.1

63

272

23

7,731

0.30

0.25

1,125

35

0.014

TABLE 6Preliminary Remediation Goals for Soil and GroundwaterAmerican Creosote Works ‐ Winnfield, Louisiana

7.0

5.0

Preliminary Remediation Goal

Soil

Shallow Aquifer Groundwater f

a Ecological PRGs were not developed for individual high molecular weight PAH compounds, but they are included in the total high molecular weight PRG calculation. The individual high molecular weight PAHS include: benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenz(a,h)anthracene, fluoranthene, indeno(1,2,3‐c,d)pyrene, and pyrene.

c Reference: Environmental Protection Agency (EPA) National Recommended Water Quality Criteria (EPA, 2014a)

250

15

30

7.0

1,340


011034


011035

Appendix A Soil Leaching to Groundwater Evaluation

011036

APPENDIX A: SOIL LEACHING TO GROUNDWATER EVALUATION


ACW SUPERFUND SITE FEASIBILITY STUDY REMEDIAL ACTION OBJECTIVES AND PRELIMINARY REMEDIAL GOALS_APPENDIX A EN0119151011SPB

011037

1

A P P E N D I X A - F I N A L T E C H N I C A L M E M O R A N D U M American Creosote Works Feasibility Study - Identification of Immobile and Mobile NAPL Area Footprints

Michael Hebert/EPA

John Knott Scott McKinley Brandon Jones‐Stanley

PREPARED BY: CH2M HILL DATE: November 14, 2014 PROJECT NUMBER: 411242

This memorandum presents an evaluation of existing information used to characterize American Creosote Works (ACW) site immobile and mobile non‐aqueous phase liquid (NAPL) contaminated soil as: 1) source material, and 2) as low‐level threat waste (LLTW) or principal threat waste (PTW). The evaluation was designed to determine if immobile NAPL contaminated soil present in the vadose zone could be characterized as non‐source material or as LLTW. Characterization of immobile NAPL contaminated soil as non‐source material or as LLTW allows engineering controls such as containment or capping to be considered viable technologies in a feasibility study or if treatment of this material is later deemed impracticable.

The evaluation included the following:

1. Comparison of polycyclic aromatic hydrocarbon (PAH) concentrations present in vadose zone soil samples tested using the synthetic precipitation leaching procedure (SPLP) to the preliminary remediation goals (PRGs) developed for groundwater that are protective for the ACW site‐specific aquatic and human health surface water exposure pathways. The soil samples were collected from a portion of the ACW site lying within a mobile NAPL contaminated soil footprint.

2. Comparison of PAH concentrations measured in vadose zone soil samples to soil leaching screening levels calculated using guidance presented in Soil Screening Guidance: User’s Guide Publication 9355.4‐23 (EPA, 1996). These samples were collected from a portion of the ACW site lying within an immobile NAPL contaminated soil footprint.

Based on the results of this evaluation, immobile NAPL present in the vadose zone is characterized as source material because it contains hazardous substances, specifically low molecular weight PAHs and pentachlorophenol (PCP), in sufficient quantity to represent a long‐term reservoir for contaminant migration to groundwater and surface water. Immobile NAPL present in the vadoze zone, and by extrapolation the saturated zone, is also characterized as PTW because this source material can generate aqueous contaminant concentrations that could pose significant risk to aquatic receptors in Creosote Branch Creek should exposure occur.

Background The concept of PTW and LLTW as developed by the U.S. Environmental Protection Agency in the National Contingency Plan (NCP) (40 Code of Federal Regulations (CFR) 300.43) is applied on a site‐specific basis when characterizing source material. Source material is defined as: “material that includes or contains hazardous substances pollutant or contaminants that act as a reservoir for migration of contamination to groundwater, to surface water, to air, or acts as a source for direct exposure”.

PREPARED FOR:

COPY TO:

011038

AMERICAN CREOSOTE WORKS FEASIBILITY STUDY - IDENTIFICATION OF IMMOBILE AND MOBILE NAPL AREA FOOTPRINTS

2

PTW are those source materials considered to be highly toxic or highly mobile that generally cannot be reliably contained or would present a significant risk to human health or the environment should exposure occur (A Guide to Principal Threat an Low Level Threat Waste, Publication 938.3‐06FS EPA, 1991). PTW includes liquids and other highly mobile materials or materials having high concentrations of toxic compounds. No “threshold level” of toxicity/risk has been established to equate to a principal threat, however, where toxicity and mobility of source material combine to pose an increased human health lifetime cancer risk of 10‐3 or greater, alternatives that treat this material should be evaluated.

LLTW is source material that generally can be reliably contained and that would present only a low risk in the event of release. It includes source materials that exhibit low toxicity, low mobility in the environment, or contain hazardous substances at concentrations near protective levels.

A determination on whether source material is a PTW or LLTW is based on its inherent toxicity as well as a consideration of the physical state of the material (e.g., liquid), the potential mobility of the wastes in the environmental setting, and its leachability and degradation products. The 1993 Record of Decision American Creosote Works Inc. Site, Winnfield, Louisiana (U.S. Environmental Protection Agency, 1993) identified contaminated groundwater, adsorbed subsurface contamination, and heavily contaminated sludges as representing the principal threats posed by the site.

Immobile and Mobile NAPL Footprint Determination As discussed above, mobility is a key characteristic that applies to the site‐specific PTW determination. NAPL occurrences at the ACW site were evaluated to geographically separate the immobile and mobile fraction as follows:

1. The 2008 subsurface soil investigation geologic logs for each of the 40 soil boring locations (GP‐1 to GP‐40) were reviewed and for each 5 foot (ft) depth interval, extending from 1 ft below ground surface (bgs) to 30 ft bgs, a determination was made on whether the NAPL present was immobile or mobile using the descriptors presented in Table 1. Mobile NAPL is defined as samples containing “Free Creosote” or “Creosote Saturated as an I (immobile) or M (mobile) on the benzo(a)pyrene (BAP) distribution maps (see Figures 1a to 1f) presented in the Remedial Investigation Report Version 1.0 (CH2M HILL, 2014).

2. A line was used to enclose the boring locations denoted by a “M” to define polygons of mobile NAPL contaminated soil for each of the six depth intervals (e.g. 1 – 5 ft bgs, 5 – 10 ft bgs, etc). No extrapolation of the information obtained from the 2008 geologic logs was performed. These polygons (Figure 2) define where mobile NAPL reservoirs occur at the ACW site.

The individual depth‐specific mobile NAPL polygons were then plotted on a site map that in turn was overlain by a similar polygon showing the aggregate immobile NAPL contaminated soil footprint. Both footprints were then compared with the boundaries of mobile NAPL defined from monitor well and recovery well/trench sump measurements performed in 2008 and 2014 (see Figure 3). The in‐well measurements are expected to overestimate the boundary of the mobile NAPL contaminated soil footprint because the wells, and their associated filter packs, provide conduits for vertical NAPL migration. Additionally, direct and hydraulic gradient induced NAPL recovery operations underway at the site since 1996 have also promoted horizontal NAPL movement. The 2012 TarGOST results were not used for this evaluation because it is not known what magnitude of TarGOST response defines mobile NAPL.

The results of this evaluation indicates the following:

Depth Interval 1 to 5 ft bgs (Figure 1a): No mobile NAPL contaminated soil is present. A large area of immobile NAPL contaminated soil that corresponds with BAP TEQ concentrations greater than 3,000 µg/Kg is present. The absence of mobile NAPL in this depth interval is consistent with the vertical migration behavior of dense non‐aqueous phase liquids (DNAPL) and natural weathering‐depletion of NAPL in the vadose zone.

011039


3

TABLE 1 Descriptors for Assessing Visual Creosote Contamination American Creosote Works Superfund Site, Winnfield, LA

Descriptor Creosote Percentage

Explanation

None 0 No visible creosote or odor present

Odor 0 A creosote odor was detected but the sample has no visible creosote present

Sheen 0 The sample has a sheen on its surface and is almost always accompanied by an odor.

Visible Creosote

1‐10 Creosote is visible as specks on soil particles but not concentrated enough to produce distinct pockets or puddles from which a separate phase could be extracted.

Free Creosote 10‐50 Pockets or puddles of creosote are present. Use light if creosote is visible in 10 ‐ 20 percent of the sample, moderate if present in 20 ‐ 40 percent of the sample, and heavy if present in 40‐50 percent of the sample.

Creosote Saturated

> 50 Creosote has displaced water that is not bound to the soil media. Creosote visibly drains from the sample.

Depth Interval 5 to 10 ft bgs (Figure 1b): Two relatively small areas of mobile NAPL occur in the vicinity of borings GP‐4 and GP‐5, along the bank of Creosote Branch Creek, and in the center portion of the site in an area enclosed by borings GP‐17, GP‐18, and GP‐24. These two areas are enclosed by a much larger halo of immobile NAPL contaminated soil that is generally consistent with footprint for the 1 to 5 ft bgs depth interval and the subsurface release of wood treating NAPL from former Impoundment 3.

Depth Interval 10 to 15 ft bgs (Figure 1c): Two relatively small areas of mobile NAPL contaminated soil are present. The larger of the two areas lies in the central portion of the site and is enclosed by borings GP‐10, GP‐11, GP‐12, and GP‐18 and GP‐19. This area is likely contiguous with the overlying mobile NAPL footprint present in the 5 to 10 ft bgs depth interval. The second are lies at the south end of the former process area between borings GP‐31 and GP‐38. This area likely correlates with the PCP‐NAPL source area. Both areas are enclosed by a larger halo of immobile NAPL that is consistent with but slightly smaller than that present in the 5 to 10 ft bgs depth interval.

Depth Interval 15 to 20 ft bgs (Figure 1d): The largest area of mobile NAPL contaminated soil present in the former process area lies at this depth interval. This region lies in the fine‐grained upper portion of the Prairie Terrance Deposits (e.g shallow aquifer). Due to the hydraulic conductivity contrast that exists between the upper and lower portion of the shallow aquifer, the current remedy has been more effective at flushing mobile NAPL from the lower portion of the shallow aquifer, a condition that is evident from the information presented on Figures 1e and 1f.

Depth Interval 20 to 25 ft bgs (Figure 1e): Two smaller areas of mobile NAPL contaminated soil are present at this depth interval. The larger of the two areas lies within an area enclosed by borings GP‐10, GP‐17, GP‐18, and GP‐25. The second area is enclosed by borings GP‐31, GP‐37, and GP‐38. Both of these areas are likely contiguous with mobile NAPL contaminated present at the 5 to 20 foot depth intervals.

Depth Interval 25 to 30 ft bgs (Figure 1f): One area of mobile NAPL contaminated soil enclosed by borings GP‐17, GP‐18, and GP‐25 is present at this depth interval. This area is expected to be contiguous with that present at the 5 to 25 foot depth intervals described above.

Mobile NAPL contaminated soil present at depths below 15 feet, which roughly corresponds to the vadose zone ‐ shallow aquifer boundary, is characterized as source material because the natural weathering and depletion of this material is responsible for the formation and persistence of a dissolved phase groundwater

011040


4

contaminant plume. Mobile NAPL contaminated soil present at depths below 15 feet is also characterized as PTW based on its inherent toxicity and mobility, and the challenges associated with reliably containing it.

Leachability of Mobile NAPL To assess if mobile NAPL contaminated soil present at depths less than 15 feet (e.g. within the vadose zone) should be characterized as source material, SPLP laboratory analysis results from testing of soil samples collected at depths of 10 to 14 ft bgs during the spring 2012 surfactant enhanced product recovery (SEPR) pilot test were reviewed. These locations, identified as 11A, 12A, 14A and 15B, were collected in the immediate vicinity of boring GP‐11 within the mobile NAPL contaminated soil footprint shown on Figure 1c.

The concentration of individual PAH constituents detected in the samples was considerable higher than the remedial goals established in 1993 ROD for the incinerator ash. PAH concentrations in the SPLP leachate (Figure 4) showed that the low molecular weight PAH constituents such as naphthalene, phenanthrene, pyrene, acenaphthene, and anthracene are leachable at concentrations ranging from 10 to 1,000 µg/L. PCP was not detected in the soil samples at concentrations above the 1.6 to 3.4 mg/Kg laboratory reporting limits nor was it detected in the SPLP leachate samples above the 13 µg/L reporting limit. The PAH concentrations in the SPLP extract were consistently higher than the groundwater PRGs established to protect surface water.

Based on the results of the SPLP testing, mobile NAPL contaminated vadose zone soil is characterized as source material because it contains hazardous substances pollutant or contaminants that act as a reservoir for migration of contamination to groundwater and surface water. This material is also characterized as PTW based on the concentration of PAHs present, which are 100 to 1000 times higher than the remedial goals established in the ROD for treated soil residuals, and because this material is readily leachable.

Leachability of Immobile NAPL To assess if immobile NAPL contaminated soil should be characterized as source material, and as PTW or LLTW, a soil screening level was calculated using Equation 10: Soil Screening Level Partitioning Equation for Migration to Groundwater (EPA, 1996) and the surface water protection PRGs presented in Table 5 of Remedial Action Objectives and Preliminary Remedial Goals for the American Creosote Works Superfund Site Feasibility Study (CH2M HILL, 2014). The screening levels ranged from 0.37 µg/L for PCP to 1,050 µg/L for naphthalene.

Selected PAH constituents and PCP concentrations measured in vadose zone soil samples collected from geoprobe borings drilled in January 2008, within the immobile NAPL footprint, were compared to the soil screening levels as shown on Figures 5, 6, and 7 for 0 to 5 feet bgs, 5 to 10 feet bgs and 10 to 15 feet bgs depth intervals, respectively. This comparison shows that these constituents, especially PCP, are present at high enough concentrations such that leaching of this material under ambient (no surface infiltration barrier) would adversely affect surface water quality through the soil leaching to groundwater and transport pathway. Therefore, immobile NAPL contaminated vadose zone soil is characterized as source material.

Placement of an impermeable cap over this material would reduce the leaching potential. If one or more remedial action alternatives presented in the draft FS Report includes installation of an impermeable soil cover over immobile NAPL source material, then this alternative(s) must include an evaluation using Equations 10 and 11 from the Soil Screening Guidance (EPA, 1996) to demonstrate the effectiveness of the cover.

011041

Figures

011042

FIGURES

ACW SUPERFUND SITE FEASIBILITY STUDY REMEDIAL ACTION OBJECTIVES AND PRELIMINARY REMEDIAL GOALS_FIGURES EN0119151011SPB


011043

Site Location

LEGEND

PLTS SupportBldg.

PLTSBldg.

Bioreactor

Pond

Tar MatAsh Disposal

Cell

T57< 2

GP-82708*N

GP-92117I

GP-770*N

GP-63305*N

GP-512,093*I

GP-4117,260I

GP-344,606I

GP-26459N

GP-12144I

GP-201092*N

GP-23111,491I/M

GP-3524,956I

GP-36170N

GP-3759N

GP-385526

GP-3927,340I GP-40

4504I

GP-3446,841I

GP-3353N

GP-3249N

GP-3110,226I

GP-3013,010I

GP-2959,779I

GP-2817,523N

GP-22295,685I

GP-247271I

GP-257397I

GP-260I

GP-272117*N

GP-21698*N

GP-19162,576I

GP-18209,454I

GP-17255,950I/M

GP-168806I

GP-155.4*N

GP-10268,810I

GP-1155,215I/M

GP-12259,140I GP-13

0N

GP-14541*N

NDU-09148

NDU-08452

NDU-072,995

PADU-1024

WDU-0958

WDU-0812

WDU-07313

WDU-06187

SDU-02399

NPDU-100.3

NPDU-1163

NPDU-12747

NPDU-13436

NPDU-0997

NPDU-0880

NPDU-07105

NPDU-15477

NPDU-1443

PADU-0826,259

PADU-122,810

PADU-11722

PADU-0995

PADU-06165

PADU-0722,230

PADU-052,581

PADU-044,128 PADU-03

5,749

PADU-0214,495

PADU-011,8391-2’ - 1,008

TMDU-01

TMDU-02

T41< 2

T422

T4316

T443 T45

13

T462

T48A< 2

T48B< 2

T48C< 2

T48D< 2

T4855

T50< 2

T51< 2

T56< 2

T49465

T472

FIGURE 1aBAP TEQ Distribution in Process Area DUSubsurface Soil (1- to 5-foot depth)American Creosote WorksWinnfield, Louisiana

0 15075

Feet

Fence

Creek (Creosote Branch)

Site Utility Roads

Immobile NAPL Extent

Tar Mat Ash Disposal Cell

2008 Geoprobe Location andBAP TEQ Concentration (μg/kg)

HOU T:\IS\Proj\American_Creosote\apr-mxd\BaP_surfer_surface_geoprobe_Oct2014.mxd gtwigg 10/7/2014 12:57:42 PM

* Indicates a BAP concentration in composite sample

30,000 to 300,000 (151,500 ft2)

3,000 to 30,000 (155,435 ft2)

BAP TEQ Concentration (μg/kg)(Dashed where Inferred)

GP-2

6459

2012 TarGOST Locations and EstimatedBAP TEQ Concentration (μg/kg)

2013 Surface Soil Sample Locations andBAP TEQ Concentration (μg/kg)

T47

2

NDU-08

452

NOTE:BAP TEQ Concentrations for 2012 TarGOSTdetermined by:BAP TEQ (μg/kg) = 0.0432 x % RE

1.59

(R2 = 0.79)

N = No NAPL ObservedI = Immobile NAPLM = Mobile NAPL

011044


011045

Site Location

LEGEND

PLTS SupportBldg.

PLTSBldg.

Bioreactor

Pond

Tar MatAsh Disposal

Cell

T573

T4912

T565

T513

T502

T4841T47

3T462

T45< 2

T44< 2

T4316

T42< 2

T41< 2

T48D4

T48C< 2 T48B

446

T48A< 2

GP-3730N

GP-2531N

GP-2113N

GP-70 UN

GP-60 UN

GP-2229N

GP-10 UN

GP-350 UN

GP-360 UN

GP-280 UN

GP-150 UN

GP-90.39

IGP-13

0 UN

GP-140 UN

GP-82,588

N

GP-231,586

I

GP-382,426

N GP-401,524

I

GP-332,566

NGP-313,277

N

GP-113,060

IGP-127,145

N

GP-590,401

I/M

GP-492,376

M

GP-2010,672

I

GP-3928,102

M

GP-3484,529

IGP-3214,030

IGP-2954,616

I

GP-2236,969

N

GP-2429,683

I/M

GP-2740,060

I

GP-1931,974

I

GP-1838,140

M

GP-1022,668

I

GP-3164,760

M

GP-30110,348

I

GP-26133,750

I

GP-17239,420

I/MGP-16No Data

N

0 15075

Feet

HOU T:\IS\Proj\American_Creosote\apr-mxd\BaP_5-10_Oct2014.mxd gtwigg 1/7/2015 1:43:48 PM

Fence


Site Utility Roads



30,000 to 300,000 (163,665 ft2)

3,000 to 30,000 (136,996 ft2)


GP-2

229


T47

3

NOTE:BAP TEQ Concentrations for 2012 TarGOSTdetermined by:BAP TEQ (μg/kg) = 0.0432 x % RE

1.59

(R2 = 0.79)

N = No NAPL ObservedI = Immobile NAPLM = Mobile NAPL

FIGURE 1bBAP TEQ Distribution in Process Area DUSubsurface Soil (5- to 10-foot depth)American Creosote WorksWinnfield, Louisiana


Mobile NAPL Extent

011046


011047

Site Location

LEGEND

PLTS SupportBldg.

PLTSBldg.

Bioreactor

Pond

Tar MatAsh Disposal

Cell

T57< 2

T49< 2

T5630

T51< 2

T50< 2

T4837

T47NT-10

T46NT-10

T45NT-10

T44NT-10

T43NT-10

T42NT-10

T41NT-10

T48D< 2

T48C< 2

T48B65

T48A< 2

GP-59N

GP-931N

GP-325I

GP-126N

GP-60 UN

GP-23999

I

GP-350 UN

GP-360 UN

GP-370 UN

GP-33556N

GP-290 UN

GP-280 UN

GP-27855

I

GP-210 UN

GP-16513N

GP-130 UN

GP-140 UN

GP-70.35

N

GP-20.48

N

GP-220.71

M

GP-150.57

N

GP-41,378

N

GP-202,084

N

GP-394,796

NGP-401,153

N

GP-344,533

I

GP-246,866

M

GP-253,023

I

GP-261,565

I

GP-811,577

M

GP-3824,072

M

GP-3216,978

I

GP-3164,549

MGP-3090,479

M

GP-1873,975

MGP-1733,510

M

GP-1061,620

M GP-1259,638

M

GP-19147,539

M

GP-11194,990

M

0 15075

Feet


NOTES:1. BAP TEQ Concentrations for 2012 TatGOSTdetermined by:BAP TEQ (μg/kg) = 0.0432 x % RE

1.59

(R2 = 0.79)

2. NT-10 = TarGOST boring not advanced below10 ft. depthN = No NAPL ObservedI = Immobile NAPLM = Mobile NAPL

Fence


Site Utility Roads



30,000 to 300,000 (92,466 ft2)

3,000 to 30,000 (105,491 ft2)


GP-2

0.48


T48

37

FIGURE 1cBAP TEQ Distribution in Process Area DUSubsurface Soil (10- to 15-foot depth)American Creosote WorksWinnfield, Louisiana


Mobile NAPL Extent

011048

smckinle

Callout

Location where SPLP samples collected from 10-15 ft.


011049

Site Location

LEGEND

PLTS SupportBldg.

PLTSBldg.

Bioreactor

Pond

Tar MatAsh Disposal

Cell

T57< 2

T49< 2

T567

T51< 2T50

< 2T4846

T47NT-10

T46NT-10

T45NT-10

T44NT-10

T43NT-10

T42NT-10

T41NT-10

T48D< 2

T48C< 2

T48B22

T48A< 2

GP-1618N

GP-95.2N

GP-70 UN

GP-60 UN

GP-50 UN

GP-40 UN

GP-30 UN

GP-27.7N

GP-10 UN

GP-20111N

GP-350 UN

GP-360 UN

GP-370 UN

GP-400 UN

GP-33175N

GP-280 UN

GP-27101

I

GP-150 UN

GP-131.1N

GP-140 UN

GP-260.88

N

GP-210.34

N

GP-84,506

M

GP-321,887

M

GP-311,842

N

GP-306,137

M

GP-245,341

I/M

GP-181,607

M

GP-121,071

M

GP-3927,410

N

GP-3460,829

M

GP-2517,150

M

GP-1935,889

M

GP-1795,790

I

GP-1057,523

M

GP-1117,666

M

GP-23RF - 12.5’

GP-38118,238

M

GP-29102,383

I/M

GP-22119,375

M

0 15075

Feet


NOTES:1. BAP TEQ Concentrations for 2012 TarGOSTdetermined by:BAP TEQ (μg/kg) = 0.0432 x % RE

1.59

(R2 = 0.79)

2. NT-10 = TarGOST boring not advanced below10 ft. depth

Fence


Site Utility Roads



30,000 to 300,000 (87,025 ft2)

3,000 to 30,000 (107,538 ft2)


GP-2

7.7


T48

48

FIGURE 1dBAP TEQ Distribution in Process Area DUSubsurface Soil (15- to 20-foot depth) American Creosote WorksWinnfield, Louisiana

RF = Refusal condition and depth encounteredN = No NAPL ObservedI = Immobile NAPLM = Mobile NAPL


Mobile NAPL Extent

011050


011051

Site Location

LEGEND

PLTS SupportBldg.

PLTSBldg.

Bioreactor

Pond

Tar MatAsh Disposal

Cell

T57< 2

T49< 2

T56< 2

T51NT-20T50

NT-20T4841T47

NT-10T46

NT-10

T45NT-10

T44NT-10

T43NT-10

T42NT-10

T41NT-10

T48D< 2

T48C< 2

T48B60

T48A< 2

GP-827N

GP-512N

GP-2715N

GP-1911N

GP-10 UN

GP-200 UN

GP-350 UN

GP-360 UN

GP-390 UN

GP-400 UN

GP-337.7N

GP-320 UM

GP-310 UM

GP-290 U

I

GP-221.1N GP-24

4.7N

GP-167.9N

GP-97.98

N

GP-10263M

GP-117.1N

GP-120 U

I GP-135.9N GP-14

0 UN

GP-60.78

N

GP-40.42

NGP-30.39

N

GP-20.39

N

GP-34NAPL

M

GP-300.47

N

GP-280.80

N

GP-260.74

N

GP-210.84

N

GP-150.81

NGP-2523,277

M

GP-1746,294

M

GP-37110,493

M

GP-38136,009

M

GP-18158,276

M

GP-7CF - 18.0’

GP-23RF - 12.5’

0 15075

Feet



1.59

(R2 = 0.79)

2. NT-10 = TarGOST boring not advanced below10 ft. depth

CF = Cockfield Formation and depth of contactRF = Refusal condition and depth encounteredN = No NAPL ObservedI = Immobile NAPLM = Mobile NAPL

Fence


Site Utility Roads



30,000 to 300,000 (51,918 ft2)

3,000 to 30,000 (53,010 ft2)


GP-20.39


T48

41

FIGURE 1eBAP TEQ Distribution in Process Area DUSubsurface Soil (20- to 25-foot depth)American Creosote WorksWinnfield, Louisiana


Mobile NAPL Extent

011052


011053

Site Location

LEGEND

PLTS SupportBldg.

PLTSBldg.

Bioreactor

Pond

Tar MatAsh Disposal

Cell

T57< 2

T49< 2

T56< 2

T51NT-20

T50NT-20

T4855

T47NT-10

T46NT-10

T45NT-10

T44NT-10

T43NT-10

T42NT-10

T41NT-10

T48DNT-25

T48C< 2

T48B< 2

T48A< 2

GP-3611N

GP-3916N

GP-3475N

GP-3353N

GP-2521M

GP-1051N

GP-1112N

GP-200 UN

GP-350 UN

GP-385.2M

GP-405.6N

GP-300 UN

GP-240 UN

GP-260 UN

GP-270 UN

GP-19500N

GP-17170M

GP-320.60

NGP-310.58

N

GP-18NAPL

M

GP-8CF - 22.5’

GP-9CF - 21.0’ GP-7

CF - 18.0’

GP-6CF - 21.0’

GP-5CF - 21.8’

GP-4CF - 24.5’GP-3

CF - 23.7’

GP-2CF - 22.5’

GP-1CF - 22.5’

GP-23RF - 12.5’

GP-37CF - 20.8’

GP-29CF - 25.0’GP-28

CF - 24.7’

GP-22CF - 24.5’

GP-21CF - 22.0’GP-16

CF - 19.0’

GP-15CF - 21.0’

GP-12CF - 24.5’ GP-13

CF - 22.0’ GP-14CF - 22.0’

0 15075

Feet

HOU \\HOLLISTER\GROUPS\IS\PROJ\AMERICAN_CREOSOTE\APR-MXD\BAP_25-30.MXD GTWIGG 10/7/2014 3:49:33 PM


1.59

(R2 = 0.79)

2. NT-10 = TarGOST boring not advanced below10 ft. depthN = No NAPL ObservedM = Mobile NAPL

Fence


Site Utility Roads



3,000 to 30,000 (15,028 ft2)


GP-31

0.58


T48

55

FIGURE 1fBAP TEQ Distribution in Process Area DUSubsurface Soil (25- to 30-foot depth)American Creosote WorksWinnfield, Louisiana

CF - Cockfield Formation anddepth of contact (ft)

CF - 18.0’

RF - Refusal condition anddepth encountered (ft)

RF - 12.5’

Mobile NAPL Extent

011054


011055

Site Location

LEGEND

PLTS SupportBldg.

PLTSBldg.

Bioreactor

Pond

Tar MatAsh Disposal

Cell

T57

T49

T56

T51

T50

T48T47T46

T45T44

T43

T42

T41

T48DT48C

T48B

T48A

GP-8

GP-9GP-7

GP-6

GP-5

GP-4GP-3

GP-2

GP-1

GP-20

GP-23

GP-35 GP-36GP-37

GP-38 GP-39

GP-40

GP-34GP-33GP-32GP-31GP-30GP-29GP-28

GP-22GP-24 GP-25 GP-26 GP-27

GP-21

GP-19GP-18

GP-17

GP-16

GP-15

GP-10 GP-11GP-12

GP-13GP-14

0 15075

Feet

HOU T:\IS\Proj\American_Creosote\apr-mxd\Mobile_NAPL_wDepths.mxd gtwigg 1/7/2015 5:13:43 PM

Fence


Site Utility Roads


2008 Geoprobe LocationGP-31

2012 TarGOST LocationT48

FIGURE 2Mobile NAPL in Soil5 to 30 Foot DepthsAmerican Creosote WorksWinnfield, Louisiana

Mobile NAPL Extent

5 to 10 Foot Depth

10 to 15 Foot Depth

15 to 20 Foot Depth

20 to 25 Foot Depth

26 to 30 Foot Depth

Immobile Footprint

011056


011057

Site Location

T:\IS\Proj\American_Creosote\apr-mxd\2014_NAPL_volume_wSoil.mxd gtwigg 11/13/2014 5:04:31 PM

PLTS SupportBldg.

PLTSBldg.

Bioreactor

Former FireWater Pond

0 10050

Feet

American Creosote WorksWinnfield, Louisiana

NAPL Distribution in ShallowAquifer Groundwater

SMW-3

SP-5

R-1

S-3

011058

smckinle

Text Box

2

smckinle

Text Box

3


011059

1,000

10,000

100,000

1,000,000

10,000,000

Acenaphthene Anthracene Fluoranthene Fluorene Naphthalene Phenanthrene Pyrene

Soil

Conc

entr

atio

n (µ

g/kg

)Vadose Zone Soil PAH Concentrations in Mobile NAPL Footprint

I11A 10 to 12 ft bgs

I12A 10 to 13.7 ft bgs

I13C 17 to 19.7 ft bgs


I15B 12.5 to 13.8 ft bgs

Remedial Goal for Incinerator Ash ‐

1,500 µg/Kg

Remedial Goal for Incinerator Ash ‐

1,500 µg/Kg

0.1

1

10

100

1000

10000

Acenaphthene Anthracene Fluoranthene Fluorene Naphthalene Phenanthrene Pyrene

SPLP L

each C

once

ntra

tion

(µg/

L)

Vadose Zone Soil SPLP Concentrations Compared to Surface Water Protection PRGs


I12A 10 to 13.7 ft bgs

I13C 17 to 19.7 ft bgs


I15B 12.5 to 13.8 ft bgsPRG ‐ 23 µg/L

PRG ‐ 11 µg/L

PRG ‐ 0.3 µg/L

PRG ‐ 250 µg/L

PRG ‐ 30 µg/L

PRG ‐ 7 µg/LPRG ‐ 6.2 µg/L

FIGURE 4Comparison of PAH and SPLP‐PAH Concentrations in Vadose Zone Soil

American Creosote Works

Winnfield, LA

011060

FIGURE 5Comparison of Immobile NAPL PAH to Soil Leaching Screening Levels


Winnfield, LA

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

Acenaphthene Anthracene Naphthalene Pentachlorophenol

Soil

Conc

entr

atio

n (µ

g/kg

)PAH Concentrations in Soil (1 to 5 ft) Lying within Immobile NAPL Footprint

Compared to Calculated Soil Leaching SSLsGP‐9: 0 to 5 ft bgs GP‐20: 0 to 5 ft bgs GP‐21: 0 to 5 ft bgs GP‐26: 0 to 5 ft bgs

GP‐27: 0 to 5 ft bgs GP‐33: 0 to 5 ft bgs GP‐40: 0 to 5 ft bgs

SSL ‐ 330 µg/kg SSL ‐ 1,050 µg/kg SSL ‐ 21 µg/kgSSL ‐ 18 µg/kg

Unfilled Columns = Not‐detected

011061



Winnfield, LA

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

100,000,000


Soil

Conc

entr

atio

n (µ

g/kg

)PAH Concentrations in Soil (5 to 10 ft) Lying within Immobile NAPL

Footprint Compared to Calculated Soil Leaching SSLsGP‐9 5 to 10 ft bgs GP‐20 5 to 10 ft bgs GP‐21 5 to 10 ft bgs GP‐26 5 to 10 ft bgsGP‐27 5 to 10 ft bgs GP‐33 5 to 10 ft bgs GP‐40 5 to 10 ft bgs

SSL ‐ 18 µg/kgSSL ‐ 330 µg/kg SSL ‐ 1,050 µg/kg SSL ‐ 21 µg/kg


011062



Winnfield, LA

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000


Soil

Conc

entr

atio

n (µ

g/kg

)PAH Concentration in Soil (10 to 15 ft) Lying within Immobile NAPL

Footprint Compared to Calculated Soil Leaching SSLs

GP‐9 10 to 15 ft bgs GP‐20 10 to 15 ft bgs GP‐21 10 to 15 ft bgs GP‐26 10 to 15 ft bgs

GP‐27 10 to 15 ft bgs GP‐33 10 to 15 ft bgs GP‐40 10 to 15 ft bgs Series1

SSL ‐ 330 µg/kg

SSL ‐ 18 µg/kg SSL ‐ 1,050 µg/kg SSL ‐ 21 µg/kg


011063

Documents

REMEDIAL ACTION OBJECTIVES AND PRELIMINARY REMEDIAL … · remedial action objectives and preliminary remedial g oals • Future Commercial/Industrial Workers – A commercial/industrial