J. Great Lakes Res., 1979Internat. Assoc. Great LakesRes., 5 (2):160-169

VOLATILE CHLORO- AND CHLOROFLUOROCARBONSIN LAKE ERIE -1977 AND 1978

Klaus L. E. Kaiser1 and Ilze ValdmanisNational Water Research Institute

Environment CanadaP.O. Box 5050

Burlington, Ontario L 7R 4A6

ABSTRAcr. Water samples from the central and eastern basins of Lake Erie were analyzed for volatilechloro- and chlorofluorocarbons for a one-week period in each of 1977 and 1978. The following con­taminants were observed with mean concentrations and standard deviations in 1978 with the correspond­ing values for 1977 in parentheses: Dichlorodifluoromethane (Freon 12) 76±38 (73±36) ngoL-1

; trichloro­fluoromethane (Freon 11) 34±26 (46±40) ngor1 .. chloroform 15±4 ngor1

.. carbon tetrachloride 19±11(37±20) ngoL-1

.. trichloroethylene 20±13(11±9) ngor1•

Except for carbon tetrachloride and trichloroethylene, the distribution patterns appear to show littlecorrelation with each other. Chloroform concentrations were relatively uniform, however the carbontetrachloride and trichloroethylene concentrations appear to be point-source related with discharges alongthe south shore of Lake Erie. Freon 12 concentrations were generally higher in the eastern basin than inthe central basin, while Freon 11 levels were high and relatively uniform throughout the study area.

INTRODUCTIONIn recent years, the contamination of the biospherewith hazardous organic compounds has become offoremost concern. The identification and measure­ment of persistent contaminants is the subject ofmany research and monitoring activities. For some,the environmental pathways are known to a largeextent; however, information is lacking on thetransport of contaminants from air to water andvice versa. For example, theoretical calculations(Mackay and Leinonen 1975; Dilling, Tefertiller,and Kalos 1975) show the rapid loss of poorlysoluble, high boiling polychlorinated biphenyls(PCBs) from water surfaces. At the same time,however, analyses of dry and wet precipitation(Strachan et al. 1979, Murphy and Rzeszutko 1977)indicate a considerable atmospheric fallout of suchcompounds onto land and water surfaces. As aresult, it appears to be still in question whetherlarge lakes act predominantly as sinks or as sourcesof such contaminants.

The findings of haloforms in raw and drinkingwaters (Symons et al. 1975) increased the interestin organic contaminants of aquatic systems, specifi­cally with respect to the more volatile components.Actual haloform concentrations and potential

1To whom correspondence should be addressed.

haloform production from common, semi-naturallyderived precursors are presently being investigatedat varied locations in Canada (Lawrence 1978).However, contaminants with little direct or un­known effects on aquatic life are seldom investi­gated in aquatic systems. The recent evidence ofchloroflouromethane (CFM)-induced modifieationof the stratospheric ozone layer (Wofsy, McElroy,and Sze 1975) has brought much emphasis on CFManalysis and monitoring in air, but without a corres­ponding interest in CFM distribution in aquaticsystems.

This paper reports the distribution of Freon 12and Freon 11 in the eastern and central parts ofLake Erie during one week in each of the summersof 1977 and 1978. In addition, information ispresented on the occurrence and distribution ofchloroform, carbon tetrachloride and trichloro­ethylene in such samples.

EXPERIMENTAL

Sampling and ProcessingWater samples were taken from CSS Limnos with aRosette Sampler with simultaneous temperature anddepth recording EBT as a part of the Lake ErieHypolimnion Oxygen Studies during the periods1130 hours, August 8 to 0400 hours, August 12,1977 and 1200 hours, June 19 to 0515 hours,

160

CHLORO- AND CHLOROFLUOROCARBONS IN LAKE ERIE 161

June 23, 1978. Sampling depths at most stationsincluded 1 m (surface) and bottom (1 m abovebottom) and samples were also frequently obtainedfrom one or more intermediate depths above orbelow the thermocline.

Immediately upon surfacing of the RosetteSampler, 125 mL of the appropriate water sampleswere transferred into 125 mL volume cylindricalseparatory funnels, equipped with 2 mm boreTeflon® stopcocks and Teflon® sleeve-lined glassstoppers. Upon transfer to the laboratory aboardthe ship, each separatory funnel was drained to asample volume of 100 mL and was again sealedwith the stopcock and immediately evacuated witha rotary pump for approximately three secondsthrough the funnel stopcock. The funnel stop­cock was closed and the evacuated funnel, with aheadspace of approx. 25 mL and 100 mL of thewater sample, was inverted and placed vertically ina thermostat-controlled water bath at 90°C, withthe level of the water bath above the water levelof the sample but below the stopcock of theseparatory funnel. A water bath temperature of90°C was selected to reduce the time for equili­bration and also to increase the method's sensi­tivity, resulting in a higher proportion of volatilesin the gas phase when compared to a bath tempera­ture of 70°C, as shown by Kaiser and Oliver (l 976).

To ensure equilibration of the volatiles betweenthe gas and liquid phases, each funnel was kept inthe water bath for a minimum of 10 minutes dur­ing which the funnel was a few times vigorouslyshaken by hand. It was then taken from the waterbath and connected in the inverted position to a15 cm long rubber tube (6 mm 10, 16 mm OD);the tubing and glass stem of the funnel wereevacuated. A 10 mL glass ampoule, previouslybaked at 450°C and also attached to the rotarypump with a Tygon® tube, was also evacuated andthen placed in liquid nitrogen. A straight, 2 mmbore, three-way glass stopcock connected theseparatory funnel via the rubber tube to therotary pump and to the ampoule via the Tygon®tubing and was used to transfer the headspacevolatiles to the glass ampoule. Care was taken toensure that only the headspace gases and watervapour from the sample were transferred to theampoule by slowly opening the funnel stopcockand closing it again after approximately 20 seconds.The glass ampoule was then taken from the liquidnitrogen bath and quickly sealed while undervacuum with a propane torch. The sealed ampouleswere kept in the dark at room temperature untilanalysis.

Analysis

Prior to the gas chromatographic (GC) analysis ofthe headspace samples contained in the sealedampoules, the gas samples were quantitatively trans­ferred into graduated 15 mL glass centrifuge tubeswith ground glass stoppers. For this, a centrifugetube was fIlled with distilled water, placed in alarge beaker containing 2 L distilled water, andinverted, taking care that no air was trappedinside. A small glass filtering funnel was insertedinto the centrifuge tube and the ampoule placedbeneath the cone of the fIltering funnel. Uponbreaking the tip of the ampoule, its gaseous contentescaped through the inverted filter funnel into thecentrifuge tube, displacing part of the water, nor­mallya 10 to 12 mL volume. Upon completion ofthe gas transfer, the centrifuge tube was stopperedunder water and placed upside-down in a wirerack. The remaining portion of the water in thecentrifuge tube thus sealed the gas sample from theair. Re-equilibration of the headspace samples withthe water in the centrifuge tubes will occur over aperiod of several days, therefore all samples wereanalyzed on the same day as the transfer.

For the GC injection, a centrifuge tube wasturned right side up and the glass stopper raised byapproximately 5 mm to create a small slit betweenthe tube and stopper. Through this slit, the needleof a 100 J.lL gas-tight syringe (needle length, 7.5cm; 0.4 mm OD) was inserted until the needle tipwas approximately 1 cm from the surface of thewater. After sampling, the syringe was withdrawnfrom the centrifuge tube. the tube again stopperedand inverted for storage. The volume of the samplein the syringe was adjusted to 100 J.l L. and thenimmediately injected into the gas chromatograph.This method of sample withdrawal allows only onequantitative injection, but further injections canbe made for qualitative confIrmation and to giveconcentration estimates analogous to the methodby Mackay, Shiu, and Wolkoff (l975).

For the GC analysis, a Tracor MT-220 gas chro­matograph with an electron-eapture detector andlinear electrometer was used. Columns used were(i) 1.8 m x 3.2 mm (I.D.) glass with 3% Dexsil-300on 80/100 mesh Gas Chrom Q. conditioned at150°C; (ii) 1.8 m x 3.2 mm (I.D.) glass with 100/120 mesh Porapak Q. precleaned by Soxhlet ex­traction with acetone and hexane, conditioned at220°C; (iii) 1.8 m x 3.2 mm (I.D.) stainless steelwith 0.2% Carbowax 20 M on 80/100 mesh Carbo­pack C, conditioned at 180° C.

Chromatograph parameters were: Inlet tempera-

162 KAISER and VALDMANIS

ture: 225°C; detector temperature: 310°C; carriergas: nitrogen at 35mL/min (pressure 2.0 kg cm-2

);

oven temperature: ambient for Dexsil-300 column,170° C for Porapak Q column, and 120°C forCarbowax 20 M column.

Standard and Injection

For quantitative purposes, both a chlorofluoro­carbon and a chlorocarbon standard were applied.The chlorocarbon standard was prepared by addi­tion of each of 50 t-tL CH2 C12 , 2 t-tL CHCh, 1 t-tLCC14 , 5 t-tL C2 HC13 , and 3 t-tL C2 Cl4 to 5 mLhexane, resulting in the primary standard solution(A). Five t-tL of A were injected into an air-filled1 L separatory funnel where it quickly volatilizedto become alL reservoir of working standard (B).Standard B was freshly prepared every week.Chlorofluorocarbon standards were prepared in aroom separate from the analytical laboratory inthe following way. Four t-tL of liquid Freon 11(at O°C) were injected into the airspace of a125 mL separatory funnel. A volume of 1000 t-tLof gaseous Freon 12 was added to this separatoryfunnel to result in the primary (gaseous) FreonStandard (C). After storing funnel C for approxi­mately 10 min to allow for homogenisation, 30 t-tLof the gas were withdrawn and injected into anair-filled 1 L separatory funnel to result in theworking standard (D) which was prepared twice aweek. A satisfactory reproducibility of such stan­dards was obtained.

For the preparation of the standard solution,appropriately sized gas-tight syringes were used.For the injections into the chromatograph, a100 t-t L glass syringe with luer tip, fitted withKel-F hub and stainless steel needle, 75 mm, 0.6mm O.D. was used throughout. All such injectionswere done using an injection volume of 100 t-tL.For the analysis of volumes of less than 100 t-t Lof either the standards or samples, the desiredvolume was withdrawn from the standard orsample and made up to 100 t-tL volume with air.This technique was also used for the spiking ofsamples and the quick preparation of other mixedgases.

Prior to the quantitation of samples or standards,several injections of 100 t-t L each of air were madeinto the chromatograph to ensure proper· stablefunctioning of the system. Gas leaks, arising inparticular from a worn septum, tended to resultin a baseline drop prior to the elution of theoxygen, providing a simple means of checking theperformance and sensitivity of the instrumentand detector.

The entire procedure was tested by determiningrecoveries from distilled water spiked with knowncontaminant concentrations. The overall recoverieswere found to be 70±7% for Freon 11, 59±10% forcarbon tetrachloride, and 51 ±15% for trichloro­ethylene. Also, duplicate water samples, taken atseveral stations, showed no increase in samplevariability. In addition, as described further, thecalculation of the cruise mean from individualsample results rather than from the station meansresulted in no significant change of the overallstandard deviation, thus indicating no unusualsample variability. The routine analytical detectionlimits for the volatiles in the Lake Erie water sam­ples were found to be 5 ng- L-1 Freon 12, 2 ng- L-lFreon 11, 4 ng- L-l chloroform, 2 ng' L- 1 carbontetrachloride, and 2 ng- L-1 trichloroethylene. Nocorrection factors were applied to the results totake the recoveries found above into account.

RESULTS AND DISCUSSION

Individual measurements for each contaminantfrom various depths at each station were combinedto result in arithmetic station means of a contami­nant for each station for each of the samplingperiods in 1977 and 1978. The number ofindivid­ual samples per station varied from station to sta­tion and between years; however, most stationscomprised at least one sample each of surface (1 mbelow surface) and bottom (1 m above bottom)water. The mean numbers of samples per stationwere 2.14 for 1978 and 2.27 for 1977. Due toincomplete sampling, loss of samples during pro­cessing and analysis, only 96 out of 107 (in 1977)and 110 (in 1978) stations were represented by thedata. The station locations are shown in Figure 1.

Combination of station means resulted in arith­metic cruise means of the contaminants for each ofthe study periods in 1977 and 1978. Table 1 givesa summary of such cruise means, the respectivestandard deviations, relative standard deviations,and concentration ranges observed. A more detailedcalculation of the cruise mean and standard devia­tion for the 205 individual sample results for Freon12 (1978) gives 74±44 ng- L-l, an insignificantlydifferent mean and higher standard deviation fromthose calculated for the 94 station means for Freon12 (1978) of 76±38 ng- L-1

• These differencesappear small enough to justify the use of theungrouped station means rather than each samplefor the calculation of the cruise means and standarddeviations. The distribution of the measured con­taminants, however, was found to vary consider­ably from station to station for each of the cruises

CHLORO- AND CHLOROFLUOROCARBONS IN LAKE ERIE 163

FREON 12 - 1978

1++"+1L±....i..J

-• SAMPLE STATIONS

FIG. 1. Location of sampling stations, 1977 and 1978, and distribution of Freon 12 in Lake Erie, station means, 1978.

TABLE 1. Cruise means, standard deviations, relative standard deviations, and ranges of Freon 12, Freon 11, chloroform,carbon tetrachloride, and trichloroethylene in the eastern and central basins of Lake Erie, 1977 and 1978, concentrationsin ng-r 1

• a) Number of station means, b) Cruise means, c) Standard deviation, d) Relative standard deviation.

1977 1978

Compound Na) xb) ± sc) (%)d) Range N x ±s (%) Range

Freon 12 91 73 ± 36 (49) 10 -190 94 76 ± 38 (50) 16-255Freon 11 90 46 ±40 (87) 6-185 94 34 ± 26 (76) 6 - 168CHCh 90 15 ± 4 (27) 5 - 34CC14 85 37 ± 20 (54) 9 -110 95 19 ± 11 (48) 4 - 53C2 HCh 96 11 ± 9 (82) 3-48 96 20 ± 13 (65) 5 - 63

as well as in between the cruises. Attempts tocorrelate chlorocarbon and Freon concentrationswith either the depth or temperature of the indi­vidual water samples were unsuccessful. Possiblya much larger number of stations and more samplesper station might show such correlations if theyexist at all.

FreonsThe chlorofluorocarbons - Freon 12 (CCl2 F2 ,

dichlorodifluoromethane) and Freon 11 (CC13 F,trichlorofluoromethane) - were observed in samplesfrom all stations, ranging in concentration fromnear the detection limits to over 200 ng- L- 1 •

Chlorofluorocarbons have been observed in tracequantities in a few finished drinking water samplesfrom the U.S. (Shackelford and Keith 1976) andthey were also reported as contaminants in largeareas of the Atlantic (Singh et al. 1979; Lovelock,

Maggs, and Wade 1973). Most commonly usedanalytical techniques for the determination ofvolatile constitutents of water are unsuited forthe detection and· quantification of the chloro­fluoromethanes as the adsorption and desorptionsteps are presumably less quantitative for theserelatively non-polar compunds. In addition, theFreons are not separated from the solvent frontunder regular gas chromatographic conditions.The techniques used here are adapted from theprocedure by Kaiser and Oliver (1976), whichdoes not involve any adsorption steps. For Freon12, the cruise means and associated standarddeviations (Table 1) were virtually identical forboth 1977 and 1978. Figure 1 shows the distri­bution of Freon 12 in 1978. In that year, levelswere found to be relatively uniform throughoutthe lake with most stations having mean valuesof SO to 100 ng- L- 1 levels, but approximately

164 KAISER and VALDMANIS

half of the stations in the eastern basin showedmeans of less than 50 ng' e 1 and one zone ofstations between the Sandusky and Cleveland areasand extending in a northerly direction showedstation means generally above 100 ng· L-1 • Overall,there has been little change from the results forFreon 12 in 1977.

Freon 11 concentrations were less than those ofFreon 12 in both 1977 and 1978. However, therelative standard deviation of the cruise means of87 and 76 per cent were significantly greater forthe Freon 11 levels than for the correspondingFreon 12 levels (Table 1). This is primarily a resultof the much less even distribution of Freon 11. Ascan be seen from the distribution of Freon 11 in1978 (Figure 2), stations in the eastern basinof Lake Erie generally had levels greater than50 ngo L-l , while the central basin had levels pre­dominantly less than SOng' L-l . In 1977, a similar

situation was observed with Freon 11 levels pre­dominantly in the range of 25 to 99 ngo L-l in theeastern basin and mostly below 25 ng· L-1 in thecentral basin of the lake.

Correlations of the Freon and chlorocarbon datafor both sampling periods are given in Table 2. In1978, for example, the correlation coefficient forthe station means of Freon 12 with those of Freon11 of 0.09 is very low and indicates a different dis­tribution pattern of the two contaminants which isalso evident from a visual comparison of Figure 1and Figure 2. In contrast, with a correlation coeffi­cient of 0.31, the Freon 12 levels of 1977 correlatemuch better with the Freon 11 levels of the sameyear. In general, the correlation coefficients (Table2) help to indicate the presence or absence of anyassociations of the contaminants. With respect tothe significance of the coefficients, however, itshould be noted that the data base is relatively

FREON 11 - 1978

25-49

_ 50-99

bo~o~o~od 100-149

FIG. 2. Distribution ofFreon 11 in Lake Erie, station means, 1978.

TABLE 2. Co"elation coefficients of the station means.

Freon 12 Freon 11 Freon 11 CHCh CC14 CC14 C2 HCh C2 HCh(1978) (1977) (1978) (1978) (1977) (1978) (1977) (1978)

Freon 12 (1977) 35 .31 .09 .10 .44 .10Freon 12 (1978) .09 .02 .31 .13Freon 11 (1977) .38 .02 .59Freon 11 (1978) .14 .23 .03CHCh (1978) .20 37CC14 (1977) .18 .03CC14 (1978) .67C2 HCh (1977) .12

CHLORO- AND CHLOROFLUOROCARBONS IN LAKE ERIE 165

small and, as a result, the observed station meansmay not be normally distributed. Hence care mustbe taken in assessing the statistical significanceof the calculated correlations. Furthermore, theextent of seasonal influences on the distributionsof the contaminants is not known at present andit may be of importance that in 1978 the samplingoccurred at an earlier date than in 1977. Therefore,a less pronounced stratification regime and a lowermean temperature of the lake may be presumedduring the sample collection in 1978. A strongchange in the correlation coefficients of any twocontaminants from one year to the next, such asfor Freon 11 and trichloroethylene, may indicatethe influence of such seasonal effects.

A variety of chlorofluoromethanes and chloro­fluorethanes have found large scale use as pro­pellants, refrigerants, and blowing agents. Inparticular, Freon 12 and Freon 11 are commonmaterials for such purposes (Howard and Han­chett 1975). The magnitude of the consumptionof these materials is apparent from the world, U.S.total, and U.S. Great Lakes basin production rates,as given in Table 3. McCarthy, Bower, and Jesson(1977) estimated that approximately 90% of thecumulative world production up to the year 1975has been released into the atmosphere. No directtoxic effects of either Freon 12 or Freon 11 tobiota at the environmental levels observed areknown. However, in recent years, concern hasarisen with respect to the adverse effect of chloro­fluorocarbons on ozone in the stratosphere. Suchconcern appears to be well founded and has resulted

in an international effort to restrict the productionand release of chlorofluorocarbons.

The solubility of each Freon in water is low anddepends on the concentration of dissolved salts,and presumably also on that of dissolved butunionized organic matter in the water. Junge (1976)reported the relative solubility of Freon 11 in purewater of lOoC as 0.25, approximately twice thevalue observed for ocean water under the sameconditions. Transfer rates of gases across the air­water interface are also affected by solutes and sur­face fIlms which lower the water surface tension(Hunter and Liss 1977). It is assumed that thedistribution of Freons in the Lake Erie water sam­ples is primarily a function of the Freon concen­trations in the overlying air and of diffusion intoand out of the water. This assumption appears tobe supported by the interpretation of Figures 1and 2, respectively, which do not show any recog­nizable plumes or concentration gradients originat­ing from the larger urban and industrialized areason the shores of the lake. The observed stationmeans result in a higher ratio of Freon 12 to Freon11 in the central basin and a lower ratio in theeastern basin of Lake Erie. With the assumption ofsimilar diffusion rates for both contaminants, itwould indicate that Freon 12 concentrations in theair are higher over the central basin and lower overthe eastern basin with the opposite holding truefor Freon 11.

Based on the observed means of Freon 12 andFreon 11 (Table 1) and assuming an uniform dis­tribution of both throughout the lake and a lake

TABLE 3. Production rates and estimated quantities in Lake Erie (1978) of Freon 12, Freon 11, CHC13 , CC14 , and CzHC13 ,

in 103 kg.

Annual Production

Worlda)U.S. Great±) Quantities in

Compound U.S. Tota1c) Lakes Basin Lake Erie

Freon 12 570,000 219,000 11,000 35Freon 11 485,000 153,000 9,000 16CHCh 245,000 5,000 6.9CC14 1,000,000 522,000

1 700000b) 390000d ) 25,000 8.7, ,680'000 e),

CzHCh 1,010,100 25,000 9.2

a) Pearson and McConnell (1975)b) Lovelock et al. (1973)c) OCPDB (1978)d) Estimated from Altshuller (1976)e) Estimated from Lovelock et al. (1973)o Estimated as approximately 1/20 of total U.S. or 1/50 of world

production

166 KAISER and VALDMANIS

volume of 460 km3 (Rainey 1967), the totalamounts in the lake were calculated as approxi­mately 35 x 103 kg Freon 12 and 16 x 103 kgFreon 11, respectively. These amounts are equiva­lent to 0.3 per cent of the estimated annualproduc­tion and presumably, the release of, Freon 12 inthe U.S. Great Lakes basin and 0.2 per cent of thatof Freon 11 (Table 3).

Recently, the global background distributions ofseveral halocarbons were reported by Singh et al.(1979). Freon 11 concentrations were shown to beat a mean of 126 x 10-12 (v/v) or 760 x 10-12 go L- 1

in the atmosphere. Similar levels were reported asbackground of Freon 11 in air over continentalNorth America (Singh et al. 1977, Wilkniss et al.1975) and in air over the North Atlantic (Lovelocket al. 1973). In contrast, the Freon 11 concentra­tions in the air of urban areas were up to 100times higher than the background level (Wilkniss etal. 1975). As large urban and industrialized areasare situated to the west and northwest of Lake, Erie,upwind from the prevailing westerly winds (Simons1976), it may be assumed that the Freon 11 con­centrations in the air over Lake Erie are alsosignificantly above the global background for muchof the time. Based on the relative solubilities ofFreon 11 in air and water S=0.25 [go Lii a/go L~lir]

as determined by Junge (1976), and on tile observedmean concentration of 34 ngoL- 1 of Freon 11 inLake Erie (Table 1) in 1978, we calculate an equi­librium concentration of 23 x 10-9 (v/v) or 136 x10--9 go L-l Freon 11 in the overlying air. This levelis approximately 180 times that of the globalbackground concentration reported by Singh et al.(1979).

Given a mean retention time of 2.6 years forLake Erie water (Rainey 1967) and presuming theinfluent to be free of contaminants, a net annualflux of 6 x 103 kg Freon from the air to the lakemay be calculated. This amount is equal to approxi­mately 0.07 per cent of the estimated annual pro­duction of Freons in the Great Lakes basin (Table­3).

ChlorocarbonsThree chlorocarbons, chloroform, carbon tetra­chloride, and trichloroethylene, were observedin most water samples from both cruises. Chloro­form has been recognized as a widespread con­taminant of drinking water (Shackelford andKeith 1976) and is thought to arise primarily fromthe chlorination of raw and wastewaters (Morrisand Baum 1978). Lawrence (1978) and Noack andDoerr (1978) investigated haloform and potential

haloform concentrations in several water sourcesand under varied conditions and confirmed thatpotential haloform concentrations are related tothe concentrations of humic materials in suchnatural waters. In addition, chloroform and,to a lesser degree, carbon tetrachloride, are formedby the disinfection of wastewater with chlorine.Comparatively little is known about the origin oftrichloroethylene in lake water. In addition to theabove-mentioned sources, each of these compoundscan enter the aquatic environment from direct dis­charges from manufacturing and use processes, aswell as from the atmosphere, as reviewed by Giger(1977). In order to relate these possible sources tothe concentrations observed, it is of interest tocompare the relevant production and use figureswith the concentrations and quantities observedas shown in Table 3.

A large survey of halomethanes in raw and fin­ished drinking water by Symons et al. (1975)reported the absence of CHCl3 and CCl4 from rawwater for Cleveland, Ohio, taken from Lake Erie.However, such fmdings can now be augmented byour results, since our detection limits and mostconcentrations observed are lower than the limitsof the above survey (50 ngoL-1 of CHCl3 or CCI4 ).

Chloroform

The distribution of chloroform in 1978 is repre­sented in Figure 3. Most stations showed levels of10 to 19 ngoL-l with little variation to either higheror lower concentrations. This result appears some­what surprising in view of the known formation ofchloroform by wastewater chlorination, which iscommonly practiced in the larger urban areas. Nolocalized effects can be seen in the observed dis­tribution of chloroform. Only partial data onchloroform are available for the 1977 cruise. Suchdata, however, appear to be quite similar to thoseof 1978, indicating no significant differencebetween the two sampling periods.

The chloroform means of each station werecompared to the means of the other contaminants(Table 2). Both with Freon 12 and Freon 11,insignificant correlation coefficients of 0.02 and0.14, respectively, were obtained for the chloro­form concentrations in 1978. The correlationcoefficients of chloroform with carbon tetra­chloride and with trichloroethylene were muchhigher for the same year. In particular, the coeffi­cient for trichloroethylene and chloroform of 0.37indicates a similar distribution pattern of these twocontaminants.

CHLORO- AND CHLOROFLUOROCARBONS IN LAKE ERIE 167

20-29

30-39fi'O"'O'O"d~

CONCENTRATION ng· L-1

1+ +++j 4-9

bJ).-;~d 10 -19

FIG. 3. Distribution ofchloroform in Lake Erie, station means, 1978.

CCI4 -1978

CONCENTRATION ng'L-1

~ 2-9

10-19

mIm3I 20-29

~~o~o~o~oJ 30 - 39

~ 40-49

Carbon tetrachloride and trichloroethylene havefrequently been observed in environmental samples.Numerous accounts establish their widespreadpresence in both marine and freshwater systems, asreviewed by Giger (1977). As is evident from acomparison of Figures 4 and 5, in Lake Erie bothcompounds show slmilar distribution patterns.Carbon tetrachloride (Figure 4) was observed atmost stations in levels up to 19 ngo L- 1

, similar to

FIG. 4. Distribution ofcarbon tetrachloride in Lake Erie, station means, 1978.

Carbon Tetrachloride and Trichloroethylene chloroform. However, in contrast to chloroform,large areas with elevated levels were observed inthe vicinities of Sandusky and Cleveland in thecentral basin and to the northeast of Erie, Pennsyl­vania, in the eastern basin of Lake Erie. The dis­tribution of carbon tetrachloride in the easternbasin appears to show particularly high concentra­tions covering an area between Erie and Westfield,Pennsylvania, and the deepest sounding.

The distribution pattern of trichloroethyleneduring the cruise period of 1978 is shown in

168 KAISER and VALDMANIS

CONCENTRATION ng·L-1

~ 2-9

10-19

_ 20-29

~ 30-49

_ 50-69

FIG. 5. Distribution of trichloroethylene in Lake Erie, station means, 1978.

Figure 5. High levels of this contaminant wereobserved in the vicinity of Erie, Pennsylvania,extending parallel to the southern shore to thecentre of the eastern basin, followed by a rapiddecline to very low levels in the northern andeastern part of the eastern basin. As with carbontetrachloride, also trichloroethylene concentrationswere higher in the areas to the east and north ofSandusky and Cleveland, respectively. In addition,a large zone of intennediate trichloroethylenelevels was observed in the central part of thecentral basin. This zone appears to have somewhathigher concentrations near the southern shore ofLake Erie close to Ashtabula, Ohio.

Apart from the Ashtabula area of the centralbasin, the visual comparison of the distributions ofcarbon tetrachloride and trichloroethylene shows astriking similarity. The correlation coefficient ofboth compounds for the 1978 period of 0.67appears significant and is the highest observed(Table 2).

The distribution of trichloroethylene during thesampling period in 1977 was similar to that of1978, except for the central part of the centralbasin where more unifonn low levels were recorded.Elevated levels were found in the southwesternpart of the central basin and throughout the easternbasin of Lake Erie. Overall, the trichloroethylenemean increased from 11 ±9 ng' L-1 in 1977 to 20± 13ng' L-1 in 1978 (Table 1) but shows an insignificantcorrelation of 0.12. In contrast, the carbon tetra­chloride mean level declined from 37±20 ng' L-l in

1977 to 19±11 ng·L-l in 1978. Furthennore, thestation means of 1977 were relatively unifonn witha zone of high values reaching from Erie, Pennsyl­vania, in a northwesterly direction to Long Pointand extending from there to approximately Long.81 0 W. Higher concentrations of carbon tetra­chloride were also observed at two central stationsin the eastern basin; however, no significantlyhigher levels were found in the area betweenSandusky and Cleveland as was the case fortrichloroethylene.

Finally, it is of interest to consider any possibleassociation of carbon tetrachloride or trichloro­ethylene with either one or both of the Freons.The highest correlation coefficient observed inthat respect, 0.59, is that of trichloroethylenewith Freon 11 in 1977 (Table 2). This value isin strong contrast to the extremely low correla­tion coefficient of 0.03 for the same compoundsin 1978. Similarly, the correlation of Freon 11with carbon tetrachloride of only 0.02 in 1977changes to 0.23 in 1978. However, the correla­tion coefficients of Freon 12 with carbon tetra­chloride of 0.44 in 1977 and 0.31 in 1978 bothappear significant, while insignificant correla­tions are found for Freon 12 and trichloroethylenefor both years. While strong local inputs of carbontetrachloride and trichloroethylene appear evidentfrom Figures 4 and 5, their underlying widespreaddistributions and significant correlations with theFreons may also indicate a partial influx from theair above the lake.

CHLORO- AND CHLOROFLUOROCARBONS IN LAKE ERIE 169

In general, it may be concluded that the Freonsare most likely to enter the aquatic system fromthe atmosphere, while the chlorocarbons are inter­preted as entering primarily from discrete pointsources associated with large urban and industrialoutfalls along the southern shore of Lake Erie.

ACKNOWLEDGMENTS

We thank Mr. H. Huneault of the Toxic SubstancesSection, the crew of CSS Limnos, and the staff ofthe Technical Operations Section of NWRI fortheir cooperation and assistance in the collectionof the samples.

REFERENCES

Altshuller, A. P. 1976. Average tropospheric concentrationof carbon tetrachloride based on industrial production,usage, and emissions. Environ. Science and Technol.10:596-598.

Dilling, W. L., Tefertiller, N. B., and Kalos, G. J. 1975.Evaporation rates and reactivities Gf methylene chloride,chloroform, 1,1 ,I-trichloroethane, trichloroethylene,tetrachloroethylene, and other chlorinated compoundsin dilute aqueous solutions. Environ. Science and Tech­nolo 9:833-838, and ibid. v. 1O,p. 1275 (1976).

Giger, W. 1977. Inventory of organic gases and volatiles inthe marine environment. Mar. Chem. 5:429442.

Howard, P. H., and Hanchett, A. 1975. Chlorofluoro­carbon sources of environmental contamination. Science189:217-219.

Hunter, K. A., and Liss, P. S. 1977. The input of organicmaterial to the oceans: Air-sea interaction,s and theorganic chemical composition of the sea surface. Mar.Chem.5:361-379.

Junge, C. 1976. The role of the oceans as a sink for chloro­fluoromethanes and similar compounds. Z. Naturforsch.3IA:482487.

Kaiser, K. L. E., and Oliver, B. G. 1976. Determination ofvolatile halogenated hydrocarbons in water by gaschromatography. Anal. Chem. 48:2207-2209.

Lawrence, J. 1978. National inventory of natural organiccompounds - an interim report. Environment Canada,Canada Centre for Inland Waters, Unpublished Report.September 1978.

Lovelock, J. E., Maggs, R. J., and Wade, R. J. 1973. Halo­genated hydrocarbons in and over the Atlantic. Nature241: 194-196.

Mackay, D., and Leinonen, P. J. 1975. Rate of evaporationof low-solubility contaminants from water bodies toatmosphere. Environ. Science and Technol. 9: 1178-1180.

, Shiu, W. Y., and Wolkoff, A. W. 1975. Gas chromato--graphic determination of low concentrations of hydro­

carbons in water by vapor phase extraction, pp. 251-258in Water Quality Parameters, ASTM STP 573, American

Society for Testing and Materials.McCarthy, R. L., Bower, F. A., and Jesson, J. P. 1977. The

fluorocarbon-ozone theory - 1. Production and release ­world production and release of CCh F and CCh F2

(Fluorocarbons 11 and 12) through 1975. Atmos.Environ. 11:491-497.

Morris, J. C., and Baum, B. 1978. Precursors and mechan­isms of the haloform formation in the chlorination ofwater supplies, pp. 2948 in R. L. Jolley, H. G6rchev,and D. H. Hamilton, Jr., [eds] , Water Chlorination,Environmental Impact and Health Effects, Vol. 2.Ann Arbor Science Publishers Inc., Ann Arbor, Mich.

Murphy, T. J., and Rzeszutko, C. P. 1977. Precipitationinputs to Lake Michigan.J. Great Lakes Res. 3:305·312.

Noack, M. G., and Doerr, R. L. 1978. Reactions ofchlorine,chlorine dioxide and mixtures thereof with humic acid,pp. 49-58 in R. L. Jolley, H. Gorchev and D. H. Hamilton,Jr. [eds.], Water Chlorination, Environmental Impactand Health Effects, Vol. 2. Ann Arbor Science Pub­lishers Inc., Ann Arbor, Mich.

OCPDB, 1978. Organic Chemicals, Producers Data Bank.Interim Draft Report. U.S. - Environmental ProtectionAgency, Contract No. 68-02-1319.

Pearson, C. R., and McConnell, G. 1975. Chlorinated C1and C2 hydrocarbons in the marine environment. Proc.R. Soc. Lond. B. 189:305-322.

Rainey, R. H. 1967. Natural displacement of pollutionfrom the Great Lakes. Science 155: 1242-1243 .

Shackelford, W. M., and Keith, L. H. 1976. Frequency oforganic compounds identified in water. U.S. - Environ­mental Protection Agency. Report No. EPA-600/4-76­062, December 1976.

Simons, T. J. 1976. Continuous dynamical computationsof water transports in Lake Erie for 1970. J. Fish. Res.Board Can. 33:371-384.

Singh, H. 8., Salas, L. J., Shigeishi, H., and Crawford, A.1977. Urban-nonurban relationships of ha10carbons,SF6, N2 0, and other atmospheric trace constituents.Atmos. Environ. 11 :819-828.

Salas, L. J., Shigeishi, H., and Scribner, E. 1979.-Atmospheric halocarbons, hydrocarbons and sulfur

hexafluoride: Global distributions, sources and sinks.Science 203: 899-903.

Strachan, W. M. J., Huneault, H., Schertzer, W. M., andElder, F. C. 1979. Organochlorines in precipitationin the Great Lakes region. Proceed. Int!. Symp. Hydro­carbo and Chlorin. Hydrocarb., in press.

Symons, J. M., Bellar, T. A., Carswell, J. K., DeMarco,J., Kropp, K. L., Robeck, G. G., Seeger, D. R., Slocum,C. J., Smith, B. L., and Stevens, A. A. 1975. Nationalorganics reconnaissance survey for halogenated organics.J. Am. Water Works Assoc. 67:634-647.

Wilkniss, P. E., Swinnerton, J. W., Lamontagne, R. A., andBressan, D. J. 1975. Trichlorofluoromethane in thetrophosphere, distribution and increase, 1971 to 1974.Science 187:832-834.

Wofsy, S. C., McElroy, M. B., and Sze, N. D. 1975. Freonconsumption: implications for atmospheric ozone.Science 187:535-537.