Perchlorate Occurrence in Ventura and Los Angeles Counties

Dennis A. DickersonExecutive Officer

California Regional Water Quality Control Board

Los Angeles Region

Perchlorate Detections

• Since 1997 perchlorate has been increasingly identified in regional groundwater– Occurrence closely associated with defense and

aerospace sites

– Highest levels of contamination most likely from “legacy” sources

• new sources not being created

– In some locations, incidental contamination resulting from other sources cannot be ruled out, e.g., fireworks, road flares, fertilizers

Where do we find the highest concentrations of perchlorate in groundwater?

• Greatest concentrations in groundwater are found closely associated with aerospace and defense sites– Aerojet (Baldwin Park)– JPL (Pasadena)– Santa Susana Field Lab (Boeing)

Significant Source Sites in Ventura County

• Boeing’s Rocketdyne SSFL – Santa Susana Field Lab

• near surface 48 ppb (ES-11)

• Chatsworth 1,600 ppb (HAR-16)

• Off-site 4-5 ppb, single detects not repeated

• San Nicholas Island – US Navy 16 ppb

– Maximum concentrations in groundwater

Other Perchlorate Detections in Ventura County

• Simi Valley– 17 detections in groundwater

• all less than 20 ppb

• 7 of the 17 detections less than 6 ppb

• no definable plume

• at present, no clear connection to SSFL as the source

• Ahmanson Ranch– 28 ppb (MW-1)

• split sample showed non-detect

• pending additional round of sampling

– Maximum concentrations in groundwater

Significant Source Sites in Los Angeles County

• Whittaker Bermite Site

– Santa Clarita - 310,000 ppb

– DTSC Order

• NASA/JPL

– Pasadena - 1,500 ppb

– USEPA Order (Superfund Site)

• Aerojet – Azusa - 2,180 ppb

– Regional Water Board Order

– Maximum concentrations in groundwater

Perchlorate found in Monitoring Wells in Azusa (BPOU)

Perchlorate found in USEPA Multi-port monitoring wells across the Baldwin Park Operable Unit (BPOU) in Azusa, California

Other Perchlorate Detections in Los Angeles County

• Central Basin

– sporadic detections have been reported in Vernon, Commerce, Norwalk and Bellflower.

• San Gabriel Basin

– perchlorate has been detected basin-wide, inside and outside designated Superfund areas.

• Pomona Valley

– the City of Pomona has reported perchlorate detections as high as 19 ppb in 23 production wells.

Perchlorate Impacts

• Ventura County

– No drinking water wells impacted

Perchlorate Impacts

• Los Angeles County

– Numerous drinking water wells impacted (over 130 total)

– Drinking water wells in the Cities of Santa Clarita, Valencia, Saugus and and Newhall have been affected.

– City of Pasadena shut down 9 of their 13 drinking water wells due to perchlorate impact

0 400 800

SCALE IN FEET

ClO4– > 500 ppb

ClO4– > 10 ppb

JPLFacility

JPLFacility

Operable Unit 2

Operable Unit 1:Source RemovalOperable Unit 1:Source Removal

Operable Unit 3:Plume ContainmentOperable Unit 3:Plume Containment

Figure 8

Treatment Options

• Treatment is possible but costly

• Current wellhead treatment systems not designed for perchlorate– retrofits are required

Regional Board ActionsSource Identification Efforts:

1997– Directed the City of El Monte, water supply companies and some dischargers to sample for perchlorate.

Analytical results ranged from 1 to 5 ppb.

1998 - Assisted USEPA with the identification of perchlorate contaminant sources in the Azusa/Baldwin Park Area.

1998 - Assisted USEPA with the revision of the 1994 Record of Decision for the Baldwin Park Operable Unit amended to include perchlorate.

Regional Board ActionsSource Identification Efforts:

1999 - Directed PRPs in El Monte Operable Unit to sample for perchlorate.

2000 - Directed Lockheed (in San Fernando Basin) and NASA/JPL (Raymond Basin) to sample for perchlorate.

2001 - Directed some dischargers in Monrovia and South El Monte to sample for perchlorate.

Regional Board ActionsSource Identification Efforts:

2002 - USEPA and the Regional Board direct PRPs

in South El Monte and Puente Valley Operable Units to sample for perchlorate and other emergent

chemicals.

2002 - Regional Board issues 13267 investigation letters to Boeing (Santa Susana Field Lab) and Ahmanson

2003 - Regional Board staff send out 433 letters to NPDES dischargers requesting a one time sampling for

perchlorate, NDMA, 1,4-dioxane and hexavalent chromium.

Recent Regional Board Actions

• Current focus is on investigation– orders issued to determine extent of

contamination

• Future actions– Cleanup and Abatement Orders where

warranted– increase source identification efforts– work with USEPA on significant sites

Conclusions• A number of distinct and significant sources of

contamination are known.

• Many sources remain to be identified

• Most identified source sites have not yet been remediated.

• The occurrence of perchlorate in groundwater poses a significant additional economic burden to conduct wellhead treatment of drinking water resources.