Monitoring of Trace Organic Contaminants in Atmospheric Precipitation

Monitoring of Trace Organic Contaminants in Atmospheric Precipitation

J. Great Lakes Res. 15(3):465-475 Internat. Assoc. Great Lakes Res., 1989 MONITORING OF TRACE ORGANIC CONTAMINANTS IN ATMOSPHERIC PRECIPITATION C. H...

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J. Great Lakes Res. 15(3):465-475 Internat. Assoc. Great Lakes Res., 1989

MONITORING OF TRACE ORGANIC CONTAMINANTS IN ATMOSPHERIC PRECIPITATION

C. H. Chan and L. H. Perkins Water Quality Branch, Ontario Region Canada Centre for Inland Waters 867 Lakeshore Road Burlington, Ontario L7R 4A6 ABSTRA CT. The design and use of a year-round sampler for trace organic contaminants in wet precipitation are described. The sampler is electronically controlled and features a 0.25-meter-square stainless steel funnel with a 4-L amber glass bottle. The whole assembly is insulated and equipped with heating elements which permit collection of ice/snow samples. The samples are preserved in situ with methylene chloride and extracted again with methylene chloride in the laboratory. A small network of four sampling stations was established in the Great Lakes basin for the purpose of obtaining a refined estimate ofatmospheric loading of trace organic pollutants to the Great Lakes. A total of 93 rain/snow samples was collected from the network during 1986. These samples were analyzed for organochlorine pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. The most significant organochlorine pesticides found were alpha-HCH, gamma-HCH (lindane), and methoxychlor with concentrations in the range of 7-10 ng/L, 4-5 ng/L, and 2-7 ng/L, respectively. Other organochlorinated pesticides were measured occasionally at sub-nanogram levels. Polychlorinated biphenyls were also widely detected with mean concentrations of 7-10 ng/L. Polycyclic aromatic hydrocarbons were detected in about 50% of the samples. Some of the prevalent polycyclic aromatic hydrocarbons were phenanthrene, methylnapthalene, fluoranthene, and pyrene with mean concentrations of 50-200 ng/L. Deposition of agricultural chemicals (HCHs) was higher in Lake Superior and Huron but precipitation at Lake Erie and Lake Ontario contained more varieties of domestic pesticides. ADDITIONAL INDEX WORDS: Toxic substances, polychlorinated biphenyls, halogenated pesticides, atmospheric deposition, sampling.

INTRODUCTION

basin (Murphy and Rzesutko 1977, Strachan and Huneault 1979). The discovery of organic contaminants in the aquatic habitats in Siskiwit Lake of Lake Superior point to atmospheric deposition as a likely source (Swain 1978). The presence and introduction of these toxic chemicals pose potential hazards to the aquatic health of the Great Lakes basin. The atmosphere is now recognized as an important pathway by which anthropogenic toxic chemicals are deposited to the Great Lakes (Eisenreich et al. 1981, Murphy et al. 1981). A mass balance model has been proposed to investigate the relative importance of organic pollutants from the atmosphere (IJC 1985, 1986). With this approach the concentrations of pollutants in rain/ snow are key information in estimating atmospheric deposition. Most of the available contaminant data on atmospheric precipitation were

The presence of organochlorine pesticides in atmospheric precipitation has been identified in various parts of Europe and North America (Cohen and Pinkerton 1966, Tarrant and Tatton 1968, Bevenue et al. 1972, Bobovnikova and Dibsteva 1980). These studies identified the global presence of isomers of hexachlorocyclohexanes (HCHs), dieldrin, and DDT and its residues in atmospheric precipitation. Results indicate that these compounds had undergone airborne transport and subsequent deposition in areas remote from the sites of the original pesticide application (Bidleman and Onley 1974, Peakall 1976). Numerous studies have identified the presence of organochlorine pesticides (OCs) and PCBs in rain and snow samples collected in the Great Lakes 465

466

CHAN and PERKINS

obtained from intermittent collection of rain/snow samples over short time periods at various locations. The data are not sufficient to provide a comprehensive database that was required for atmospheric deposition estimates. A monitoring strategy to collect precipitation samples at fixed locations along the Great Lakes at regular time intervals was adopted to establish a more reliable database for atmospheric deposition estimates. The sampling and measurement of organic compounds in atmospheric precipitation is relatively more complex than inorganic compounds because of the different chemistries and extremely low concentrations involved. A review of organic compounds in bulk and wet-only precipitation by Mazurek and Simoneit (1986) concluded that there is substantial lack of consistent methodology for sample collection, preservation, storage, analysis, and data interpretation, and that research is needed to address these deficiencies. A common approach is to collect a large volume of rain/snow in a glass or stainless steel container, and extract the organic chemicals with solvent or solid adsorbents. Wells and Johnstone (1978) used siliconecoated polyurethane foam plugs to extract organochlorine residues from rainwater. Murphy and Rzesutko (1977) employed a built-in glassfiber filter to extract the sample at the time of collection, while Strachan and Huneault (1979) used XAD-2 resins to concentrate OCs and PCBs in rain. Pankow et al. (1984) used Tenax-GC as a preconcentration medium for a range of polynuclear aromatic hydrocarbons. Kawamura and Kaplan (1983) extracted rain water with methylene chloride and identified 300 organic compounds. Few of the collectors cited in the literature are designed to operate unattended in remote locations or under freezing conditions. The Water Quality of Environment Canada has developed a precipitation collector for year-round collection of rain and snow samples for organic analysis. Two of these collectors were employed on the north shore of Lake Superior for over 2 years and experienced no major problems. In 1984, the sampling of trace organic contaminants in wet deposition was extended to the lower Great Lakes resulting in a network of four stations, one on each lake bordering Canada. This is the first attempt to establish a precipitation network for long-term monitoring of trace organic contaminants in wet precipitation on a regular and routine basis. This report summarizes the first full year of data from this network.

FIG. 1. Interior of precipitation sampler.

SAMPLING METHODOLOGY The precipitation sampler used in this study is a modified version of the Strachan-Huneault sampler (1984). It consists of a square stainless steel funnel measuring half a meter by half a meter, a movable lid, an electronic moisture sensor, and a motor. The movement of the lid is controlled by the moisture sensor which is set on an arm about 0.5 m from the frame of the sampler. The underside of the funnel is lined with thermally-controlled heating cable to melt any snow or frozen precipitation. The funnel drains into a compartment which houses the sample container, a 4-L amber glass bottle which contains about 200 mL of methylene chloride (Fig. 1). The compartment is insulated with 112" of styrofoam and the temperature inside the compartment is maintained above freezing during winter months with two thermostatically controlled 50-watt heaters. A 112" flexible Teflon tube connects the funnel to a glass tube which extends into the methylene chloride layer at the bottom of the 4-L amber glass bottle. This tubing passes through a pinched clamp which is electronically controlled by a solenoid valve. Upon draining into the bottle, the water sample, being lighter than the solvent, is thus forced through the solvent layer, floats to the top, and forms a layer over the solvent. During dry periods,

ORGANIC CONTAMINANTS IN ATMOSPHERIC PRECIPITATION the clamp pinches against the Teflon tubing thus isolating the sample from the atmosphere. Another solenoid valve is fitted on the cap of the amber bottle for venting and drainage into another bottle in case of overflow. The opening and closing of the two valves synchronize with the movement of the lid. This feature caps the sample immediately after sample collection, minimizing interferences from dry deposition and sample loss due to evaporation of either solvent or sample. Prior to deployment in the field, the funnel and tubing were cleaned with soap and water and then rinsed thoroughly with water, followed by reagentgrade acetone and petroleum-ether. The amber glass bottle was tared and approximately 200 mL of pesticide grade methylene chloride was added to the bottle which was then placed inside the sampler. At the end of a 2-week period, or whenever the sampling bottle was full, the funnel was rinsed with fresh methylene chloride, and the sample bottle was changed. The sample bottle was then sent to Water Quality National Laboratory at Burlington for analysis. At the laboratory, the sample was kept refrigerated at 4°C until analyzed at which time the aqueous phase was separated from the solvent and its volume measured. The aqueous phase was then extracted twice with fresh methylene chloride. The combined extracts were dried with anhydrous sodium sulphate then concentrated to 1.5 mL in isooctane. 1.0 mL of the concentrated extract was cleaned on a 3 % deactivated silica gel column by elution with 25 mL of hexane and then 30 mL of benzene. The two concentrated fractions were then analysed on GLC-ECD for organochlorine pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons following standard laboratory procedures. Detailed methods of the analysis are described in Analytical Methods Manual (1979). The organic compounds analyzed included lindane, hexachlorocyclohexane, dieldrin, aldrin, DDT and its residues, mirex, and endosulfans, and polychlorinated biphenyls. Field blanks (clean bottles with methylene chloride) were submitted along with regular samples. SAMPLING SITES The locations of the four sampling sites are shown in Figure 2. Siting criteria are distant from major urban centers and absence of local sources, and proximity to the lake, open field, power supply, and accessibility. Sibley Provincial Park is located on the north

467

shore of Lake Superior about 45 km east of Thunder Bay. The sampler was installed on the property of a local resident, at the tip of the peninsula at Silver Inlet, on the shoreline of Lake Superior. This site has been in operation since 1984. South Baymouth is located at the southern end of Manitoulin Island, just between Georgian Bay and Lake Huron. The sampler is located along the shoreline of Lake Huron at the Fishery Research Station of the Ontario Ministry of Natural Resources. Pelee Island is the largest island at the western end of Lake Erie. The sampler is situated at the island airfield. However, air traffic is extremely light. Wolfe Island is at the eastern end of Lake Ontario, just at the entrance to the St. Lawrence River. The sampler is located on the south side of the island on the river, on a private lot. RESULTS AND DISCUSSION A total of 93 samples was collected during the reported period. About one third of these samples were snow/ice samples. Average volume per sample was 3.3 liters. Six field blank samples were submitted periodically to the laboratory for analysis along with the regular samples. The results of these blank samples are shown in Table 1. Interference/ contamination from field blanks was minimal. Only trace quantities of OCs were detected in one blank from Pelee Island and the rest of the blank samples were clean. Not all the OCs were found in rain/snow samples. Certain compounds were present more frequently and in higher concentrations than others. In summarizing these results, a simple average based on a few measurements or detections would overstate the levels of contaminants in precipitation. To overcome this situation, a yearly volumeweighted mean (VMW) concentration, based on the total volume collected over the 12-month period, would probably be a more realistic statistic. The results are summarized in Tables 2-3, and Figures 3-4. The relative composition of organic pollutants in atmospheric precipitation is probably determined by their relative abundance in the atmosphere, . and also by their physical and chemical properties such as solubilities, partition coefficients, adsorption characteristics, wash out ratio, etc. The distribution of organochlorine and PAHs in wet precipitation from all four sites are profiled

CHAN and PERKINS

468 92"

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I

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'3'

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9"

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FIG. 2. Sampling locations for organic precipitation.

TABLE 1.

Results of field blanks samples (ng).

STATION DATES BHD alpha-HCH EMX alpha-endosufane LIN gamma-HCH HEP heptachlor CHC gamma-chlordane CHA alpha-chlordane HEO dieldrin DDP p,p'-DDT PCBs

SIBLEY SIBLEY SBM PELEE PELEE PELEE WOLFE 02-Feb-86 30-May-86 OI-Jun-86 07-May-86 II-Jul-86 28-Jul-86 20-May-86 4.5 1.1 4.1 1.5 2.1 3.3 1.9 4.4 13.7

469

ORGANIC CONTAMINANTS IN ATMOSPHERIC PRECIPITATION TABLE 2.

Volume weighted mean concentration (ng/L) and range of DCs and PCBs in precipitation. SIBLEY [20] MEAN RANGE

BHD LIN HEP ALD HEX CHC CHA EMX DDE HEO END DDO TDP DDP EMY MIR MEY PCBs

0.5- 3.4

0.01 0.28 0.47

(1) (4) (6)

0.3 0.8- 1.8 0.4- 3.0

0.3- 4.1 3.3-13.7

1.08 (9) 8.12 (18)

0.5- 6.8 0.8-32.3

3.44 (15) 6.89 (24)

0.4-35.7 1.2- 8.9

0.01 (1) 0.05 (2) 0.04 (2) 0.01 (1) 0.24 (6) 0.06 (2) 0.46 (11)

0.2 0.3- 0.5 0.4 0.3 0.2- 2.4 0.4 0.3- 1.0

0.03

(1) (1)

0.3 1.2

0.52

(7)

0.76 (8) 5.15 (16)

9.64 (18) 5.05 (18)

0.06 (3) 0.05 (2) 0.32 (7) 0.04 (2) 0.44 (12)

5.3-17.2 1.7-13.0

0.30.30.30.40.3-

WOLFE [24] MEAN RANGE

PELEE [31] RANGE MEAN 7.47 4.36 0.01 0.24 0.24 0.36 0.18 1.41 0.32 1.81 0.11 0.02 0.08 0.44 2.42

10.23 (20) 3.93 (18)

om

S. BAYMOUTH [18] MEAN RANGE

0.7 0.4 1.5 0.7 1.6

(31) (31) (1) (3) (13) (23) (13) (21) (14) (24) (7) (3) (5) (12) (16)

2.8-17.3 1.4-12.8 0.4 0.4- 3.4 0.2- 1.8 0.2- 1.2 0.1- 1.1 0.2- 9.0 0.2- 2.5 0.6- 5.9 0.2- 1.0 0.2 0.1- 1.1 0.6- 1.6 0.3-14.0 0.8-38.0 2.5-58.4

7.72 (24) 3.94 (24)

1.0-26.0 0.5-23.0

0.10 (1) 0.02 (3) 0.05 (3) 0.03 (2) 1.03 (15) 0.14 (6) 0.41 (17) 0.04 (I)

2.3 0.1- 0.2 0.1--0.9 0.2 0.2- 6.0 0.3- 1.4 0.1- 3.4 0.1

0.01 (3) 0.29 (5) 1.62 (13)

0.1 0.3- 4.3 0.5-25.4

1.83 (9) 4.78 (19)

1.0-22.6 1.0-22.6

[ ] number of samples collected ( ) number of detection BHD alpha-HCH, LIN beta-HCH, HEP heptachlor, ALD aldrin, HEX heptachlor epoxide, CHC gamma-chlordane, CHA alpha-chlordane, EMX alpha-endosulfan, DDE p,p'-DDE, HEO dieldrin, ED endrin, DDO 0, p'-DDT, TDP p, p'-TDE, DDP p,p'-DDT, EMY beta-endosulfan, MIR mirex, MEY methoxychlor, PCBs total PCBs.

TABLE 3.

Volume weighted mean concentration (ng/L) and range of PAHs in precipitation.

INDENE (IND) TETRAHYDRANAPTHA (TET) 2-METHYLNAPTHALENE (2MT) QUINOLINE (QUN) I-METHYLNAPHALENE (IMT) b-CHLORONAPTHALENE (BCL) ACENAPTHALENE (ACE) ACENAPTHENE(ACN) FLUORENE (FLU) PHENANTHRENE (PHN) FLUORANTHENE (FLT) PYRENE (PYR) PAHS (total) [ ] number of samples collected ( ) number of detection

SIBLEY [20] RANGE MEAN

SOUTH BAYMOUTH [18] MEAN RANGE

21.3 (10) 9.8-137.4 15.9 (10) 11.1- 89.9 27.6 (12) 4.9-183.6

11.2 16.6 26.9

4.9-320.1

11.4 1.0 0.7 3.7 5.9 132.3 149.7 99.7 459.1

52.0 (12)

3.0 (3) 3.7- 37.2 5.8 (6) 7.6- 36.7 47.2 (9) 9.8-364.7 58.1 (10) 9.8-610.7 26.7 (7) 3.7-212.0 34.5 (6) 10.9-591.6 302.1 (16) 25.9-1774

(9) (8) (8)

7.5- 45.1 7.5- 75.6 2.6-339.2

PELEE [31] MEAN RANGE 5.3 (9) 5.4 (7) 5.8 (13)

(8) 2.6-105.5 9.7 (1) 15.1 (1) 9.9 0.8 (3) 5.0- 40.7 1.3 (3) 5.0- 71.4 5.6 (14) 9.9-1233 23.5 (15) 19.8-798.8 29.7 (12) 19.6-534.2 13.5 (16) 93-2689 100.7

(13)

WOLFE [24] MEAN RANGE

5.0- 92.1 4.9- 41.1 9.9- 38.2

19.2 (9) 16.9-272.2 12.7 (10) 12.1-181.8 7.8 (12) 5.3-106.6

7.5- 53.4

10.6 (10)

5.2- 83.3

(2) 4.9- 19.5 2.0 (1) 76.9 17.1 (3) 5.0- 19.5 0.4 (1) (5) 5.0- 87.2 2.5 (2) 21.0- 81.2 (18) 9.5-140.1 13.2 (8) 13.3- 79.5 (18) 9.8-181.5 30.2 (13) 0.1-181.8 (13) 14.5-114.6 10.4 (7) 10.5- 98.5 (23) 35.2-490.4 109.2 (18) 0.2-924.4

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CHAN and PERKINS

-

ng/ L

12

10

SIB (20)

~ SBM (18)

8

6

PEL (31) WOL (25)

4

2

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o

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HIE

nJn...

n

o

o

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FIG. 3. Weighted mean concentrations of Des.

-

ng/L

160 140 120 100 80

SIB(20)

~ SBM(18) PEL(31 ) WI(25)

60 40 20 0 I

T

2

Q

1

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P

M

M

C

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T

T

L

E

N

U

H N

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0

U N

A C

P

E

B C

F

N

T

R

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FIG. 4. Weighted mean concentrations of PAHs.

ORGANIC CONTAMINANTS IN ATMOSPHERIC PRECIPITATION in Figure 3 and Figure 4. The profiles are very similar. The organochlorines are dominated by HCHs an PCBs while the dominant PAHs are phenanthrene, fluoranthene, and pyrene. HEXACHLOROCYCLOHEXANES (HCHs): alpha-HCH (BHD) and gamma-HCH (LIN) The two HCH isomers, commonly used in agriculture for seed treatment to control insects, are widely found throughout the Great Lakes basin (Strachan and Edwards 1984) and are prevalent in surface waters across Canada (Environment Canada 1977). They are also the most dominant OC in precipitation, with a combined concentration of > 15 ng/L. Of the two isomers, alpha-HCH is the predominant form. Mean concentration of BHD was 10.5 ng/L, about twice the concentation of gamma-HCH (LIN). POLYCHLORINATED BIPHENYLS (PCBs) The ubiquitous presence and persistence of PCBs have generated many studies on its transport, deposition, pathway, and impact on the environment (Simmons 1984). PCBs in the atmosphere have been reported to be associated principally with particulate matter or to exist in vapor form (Murphy et of. 1981). Eisenreich et of. (1981), based on a wet PCB concentration of 25-30 p.g/L, estimated wet deposition loading to Lake Superior to be 1,500-3,000 kg/yr, representing 60-80070 of total atmospheric deposition. The VWM concentration of PCBs in this study was in the range of 5-8 ng/L, considerably less than the 25-30 ng/L. PCBs data from the Algoma District collected by Strachan and Huneault (1984) ranged from 1-8 ng/L. Thus it seems that PCBs in atmospheric precipitation are highly variable. DIELDRIN (HEO) AND ALDRIN (ALD) Dieldrin is also found throughout the environment (Strachan and Edwards 1984) although concentrations are lower than those of HCH. Dieldrin is the oxidation product of aldrin (Ross and Crosby 1975) and, therefore, is more likely to be found in the environment than aldrin. Dieldrin was measured in > 60% of the samples while aldrin was rarely detected. Dieldrin was detected more frequently at Pelee Island at concentrations of 2.3 ng/ L, substantially higher than those measured at the other stations. The level of HEO in wet precipitation was generally < 1.0 ng/L for the upper lakes and slightly higher in the lower lakes.

471

DDT RESIDUES AND METHOXYCHLOR (MEY) Use of DDT has been banned since 1971, but DDT and its residues are still being detected in atmospheric precipitation, usually at sub-nanogram levels. DDT detections at the upper lake stations were less than 10%, but detections at the lower lakes stations were considerably higher (30-45 %). Methoxychlor, the methoxy analog of DDT, was found more frequently and at higher concentrations at the lower lake stations. POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) Polycyclic aromatic hydrocarbons have been identified in precipitation samples from many parts of Europe (Schrimpff et of. 1979, Schmitt 1982) and the U.S. (Wade 1983, Pankow et oJ. 1984, and Kawamura and Kaplan 1983). Within the Great Lakes, PAHs were measured in air samples from urban centers (Katz et of. 1978) but PAHs data in precipitation are lacking. PAHs examined were limited to the 12 lower molecular weight compounds, seven of which were quantified fairly regularly. The concentration profiles of PAHs in precipitation are shown in Figure 4. The most abundant were phenanthrene, fluoranthene, pyrene, and methylnapthalene. The statistical results are summarised in Table 3. Generally, levels of PAHs were higher than OCs. Mean weighted concentration of fluoranthene ranged from 24-96 ng/L, and pyrene ranged from 13-64 ng/L. SPATIAL AND TEMPORAL VARIATIONS Figure 3, which shows the weighted mean concentrations of OCs from the network, suggests that deposition of BHCs was higher in the upper lakes whereas other OCs (such as chlordanes, DOTs, methoxychlor, and dieldrin) were fairly uniform over the four sites. However, when the unweighted arithmetric mean concentrations, based on the number of detection, are plotted, there is a noticeable difference between the lower lake and the upper lake stations (Fig. 5). An examination of the frequency of detection (Fig. 6) also shows that the lower lakes stations have higher frequency of detection of chlordane, dieldrin, DOTs, and methoxychlor. This pattern may reflect the regional distribution of these compounds in the atmosphere. HCHs were commonly used in agriculture and forestry for controlling insect infesta-

472

CHAN and PERKINS ng/L

12 , . . : - - - - - - - - - - - - - - - - - - - - - - - - - - - , _

10

S1B (20)

~ SBM (18) PEL (310

8

_

WOL (25)

6

4

2

0 H

B

L I

D

N

H E P

A,

L

D

H E X

C

C

E

H

H

M

D D

H E

N

C

A

X

E

0

D

D D 0

E

T D

D D

P

P

E

M

M

M Y

I R

E Y

P C B

s

FIG. 5. Unweighted mean concentrations of DCs.

% 120,-----------------------------•

~ 5BM(18)

518(20)

PEL(31)

_

WI(25)

100

80

60

40

20

0 B H

D

L

I N

H E P

A L

D

H E X

C

C

E

H

H A

M X

C

D D

H E

E N

E

0

D

FIG. 6. Percentage frequencies of detection of DCs.

D D 0

T D

D D

M

M I

P

P

Y

R

E

M

E y

P C B s

ORGANIC CONTAMINANTS IN ATMOSPHERIC PRECIPITATION

473

ng/L 25 _

1984 (21)

~

1985 (25)

20

1986(20)

15

10

5

011 B H D

-....n

L I N

H

E P

A L D

H

E X

C H C

C H A

E M X

D D

E

.,,[]

"m

H

E

E 0

N D

D D 0

T D

D D

P

P

E M y

M I

R

M E y

P C B S

FIG. 7. Weighted mean concentrations of oes at Sibley.

tion. Since the mid-seventies, the commerical use of gamma-HCH in Canada has been restricted to seed treatment. It annually ranks in the top ten insecticides in Canada especially in the Prairies (Environment Canada 1987). The higher HCHs values recorded in the upper lakes may be associated with seed planting in the Prairies. Other organochlorine compounds such as methoxychlor, dieldrin, chlordane, etc. are common in gardening and household pesticides. Their more frequent occurrences and higher concentrations found in the lower lakes may be indicative of insecticide use in urban areas. South Baymouth and Pelee Island have higher PCBs deposition than Sibley and Provincial Park and Wolfe Island. This is probably due to their proximity to the large industrial and urban centers. Murphy and Rzesutko (1977) also attributed the north-south gradient of higher PCBs in southern Michigan to the closeness to large cities. Higher PAHs deposition were measured in the upper lake stations (Fig. 4). PAHs in precipitation are associated with fossil fuels and combustion residues (Junk and Ford 1980, and Simmoneit 1984). Contrary to expectation, higher PAHs were found

in the upper lakes, farther away from the industrial and urban centers in the lower lakes where consumption of fossil fuel are higher. It is possible that the higher PAHs at South Baymouth and Sibley Provincial Park are localized effects from domestic woodburning. The above discussion seems to support the observations of Schrimpff et al. (1979), who studied regional patterns of contaminants (pesticides and PAHs) in snow of northeast Bavaria. They found that PAHs and pesticides had different distribution patterns in that PAHs were affected by urbanization and industries whereas pesticides were not due to the diffuse sources of pesticides in agricultural and forested lands. Temporally, Sibley Provincial Park is the only station with 2 112 years of uninterrupted data. Figure 7 summarizes the VMW concentration of OCs from 1984-86. There is a noticeable decline in HCH deposition at Sibley Provincial Park although the use of HCHs has been restricted since the seventies. Volume weighted concentration shows a decrease from 24 ng/L in 1984 to 10 ng/L in 1986. However, the trend in PCBs is not quite as definitive.

CHAN and PERKINS

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SUMMARY AND CONCLUSIONS Based on the results collected to date, the precipitation sampler described is capable of routinely collecting rain and snow samples for organic analysis. The heated funnel with an insulated chamber and in situ solvent preservation have made it possible to quantify organochlorine pesticides and PCBs at the subnanogram per liter level. Atmospheric precipitation within the Great Lakes contains quantifiable quantities of HCHs, dieldrin, and PCBs. HCHs comprise the major fraction of organochlorine pesticides in wet precipitation. Other organochlorine pesticides were detected occasionally at sub-nanogram level or not detected. Deposition of agricultural chemicals (HCHs) were higher at Lake Superior and Lake Huron, but precipitation at Lake Erie and Lake Ontario contained more domestic pesticides. REFERENCES Analytical Methods Manual. 1979. Water Quality Branch, Inland Waters Directorate, Environment Canada, Ottawa. Bevenue, A., Ogata, J. N., and Hylin, J. W. 1972. Organochlorine pesticides in rainwater in Hawaii, 1971-1972. Bull. Environ. Contam. Toxicol. 8:238. Bidleman, T. E, and Onley, C. E. 1974. Chlorinated hydrocarbons in the Sargasso Sea atmospheric and surface water. Science 183:516-518. Bobovnikova, T. I., and Dibsteva, A. V. 1980. Organochlorine pesticides in atmospheric precipitation. Meterol. Gidrol. 46. Cohen, J. M., and Pinkerton, C. 1966. Widespread translocation of pesticides by air transport and rainout. In Organic Pesticides in the Environment, Gould, R. F., ed., p. 163. American Chemical Society, Adv. Chern. Ser. 60. Eisenreich, S. J., Hollod, G. J., and Johnson, T. C. 1981. Atmospheric concentrations and deposition of polychlorinated biphenyls to Lake Superior. In Atmospheric Pollutants in Natural Waters, pp.425-444. S. J. Eisenreich (ed.), Ann Arbor: Ann Arbor Science. Environment Canada. 1977. Surface water quality in Canada-An overview. Water Quality Branch, Inland Waters Directorate, Environment Canada, Ottawa. _ _ _ _ , 1987. Pesticide Register Survey, 1986 Report. Environment Canada-Agriculture Canada. Commercial Chemicals Branch, Conservation and Protection, Ottawa. International Joint Commission (IJC). 1985. 1985 Report on Great Lakes Water Quality. Great Lakes Water Quality Board.

_ _ _ _ .1986. Summary Report ofthe Workshop on Great Lakes Atmospheric Deposition. Junk, G. A., and Ford, C. S. 1980. A review of organic emissions from selected combustion processes. Chemosphere 9:187. Katz, M., Sakuma, T., and Ho, A. 1978. Chromatographic and spectral analysis of polynuclear aromatic hydrocarbons - quantitative distribution in air of Ontario cities. Environ. Sci. Technol. 12:909-914. Kawamura, K., and Kaplan, R. 1983. Organic compounds in the rainwater of Los Angeles. Environ. Sci. Technol. 17:497-501. Mazurek, M. A., and Simoneit, B. R. T., 1986. Organic Components in Bulk and Wet-Only Precipitation. CRC Critical Reviews in Environmental ControI16:1-140. Murphy, T. J., and Rzesutko, C. P., 1977. Precipitation inputs of PCBs to Lake Michigan. J. Great Lakes Res. 3:305-312. _ _ _ _ , Schinsky, A., Paolucci, G., and Rzesutko, C. P. 1981. Inputs of polychlorinated biphenyls from the atmosphere to Lakes Huron and Michigan. In Precipitation in Atmospheric Pollutants in Natural Waters, S. J. Eisenreich (ed.), pp. 445-458. Ann Arbor: Ann Arbor Science. Pankow, J. F., Isabelle, L. M., and Asher, W. E. 1984. Trace organic compounds in rain, I. Sampler design and analysis by adsorption thermal desorption (ATD). Environ. Sci. Technol. 18:310-318. Peakall, D. B. 1976. DDT in rainwater in New York following application in the Pacific Northwest. Atmos. Environ. 10:899. Ross, R. D., and Crosby, D. G. 1975. The photooxidation of aldrin in water. Chemosphere 4:277-282. Schmitt, G. 1982. Seasonal and regional distribution of polycyclic aromatic hydrocarbons in precipitation in the Rhein-Mann area. In Deposition of Atmospheric Pollutants, Georgii, H. W., and Prankrath, J. eds., p. 133. D. Reidel: Boston. Schrimpff, E., Thomas, W., and Herrmann, R. 1979. Regional patterns of contaminants (PAHs, pesticides, and trace metals) in snow of Northeast Bavaria and their relationship to human and orographic effect. Water, Air and Soil Pollution 11:481-497. Simmoneit, B. R. T. 1984. Organic matter of the troposphere. III. Characterization and sources of petroleum and pyrogenic residues in aerosols over the western United States. Atmos. Environ. 18:51. Simmons, M. S. 1984. PCB contamination in the Great Lakes. In Toxic Contaminants in the Great Lakes, Nriagu, J. O. and Simmons, M. S., (eds.), pp. 287-309. New York: John Wiley & Sons. Strachan, W. M. J., and Edwards, C. J. 1984. Organic pollutants in Lake Ontario. In Toxic Contaminants in the Great Lakes, J. O. Nriagu and M. S. Simmons (eds.). New York: John Wiley & Sons.

ORGANIC CONTAMINANTS IN ATMOSPHERIC PRECIPITATION _ _ _ _ , and Huneault, H. 1979. Polychlorinated biphenyl and organochlorine pesticides in Great Lakes precipitation. J. Great Lakes Res. 5:61-68. _ _ _ _ , and Huneault, H. 1984. Automated rain sampler for trace organic substances. Environ. Sci. Techno/. 18:127-130. Swain, W. R. 1978. Chlorinated organic residues in fish, water, and precipitation from the vicinity of Isle Royale, Lake Superior. J. Great Lakes Res. 4:398407.

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Tarrant, K. R., and Tatton, J. O. 1968. Organochlorine pesticides in rainwater in the British Isles. Nature 219:725. Wade, T. L. 1983. Bulk atmospheric deposition of hydrocarbons to lower Chesapeake Bay. Atmos. Environ. 17:2311. Wells, D. E., and Johnstone, S. J. 1978. The occurrence of organochlorine residues in rainwater. Water, Air, Soil Pol/ut. 9:271.