R. Frank

Mirex in the Sediments of Lake Ontario

Abstract Analysis of sediment samples collected in Lake Ontario in 1968 revealed the occurrence of mirex in two anomalous zones related to input from the Niagara and Oswego Rivers. These anomalies were confirmed in a 1976 resampling program. A suspended solids sample taken in the Niagara River confirmed an upstream source (Hooker Chemical) of the compound. Bottom sediment samples in the Oswego River identified an industrial source (Armstrong Cork) 14 km upstream of the river mouth. Known use of mirex by this plant indicated a substantial loss some 15 years ago. This was confirmed by sediment coring in the open lake sediments indicating that mirex deposition commenced 7 to 14 years before present.

Changes in mercury levels in harbor porpoises from the Bay of Fundy, Canada, and adjacent waters during 1969–1977

Mercury levels were studied in a sample of 146 harbor porpoises taken in the Bay of Fundy, Canada, and adjacent waters during 1969–77. Mean concentrations of total mercury recorded in 5-year old males (exemplifying sexually mature adults) were 1.12 ppm in axial muscle, 0.38 in cerebrum, 0.31 in cerebellum, 2.00 in kidney, and 15.7 in liver. Respective means in tissues of 5-year old females were 1.46, 0.42, 0.21 2.77 and 16.2 ppm. There was a clear correlation of increase in total Hg with age in the tissues examined. Except in the liver, mercury levels were less well correlated with weight and body length than with age. Hg levels were not significantly correlated (p > 0.05) with weight and lengthwithin age classes, except marginally in the case of liver (P ⩾0.10). Hg in muscle was virtually all in the methylated form, but in liver only about 17% was methylated. The proportions in other tissues were intermediate (kidney about 41%, mam-mary gland about 46%, brain about 8 to 52%). Levels in liver were thought to be those giving the best indication of changes in background levels of mercury in the food chain. Significant changes in Hg tissue levels appear to have occurred during the 9-year study period. Liver Hg levels in both sexes decreased from 1970 to 1971, remained low for 3 years, increased again in 1974, and continued to do so in the years following. Data are presented suggesting that this also occurred in other tissues. Since there is no evidence of a change in diet in this period, we speculate that the decline in Hg levels could be correlated with a dominance of relatively mercury-poor Gulf Stream water in the Bay of Fundy approaches in 1971–73, as opposed to the usual dominance by waters of the Nova Scotia current.

Organochlorine Insecticides and PCB in Surficial Sediments (1968) and Sediment Cores (1976) from Lake Ontario

Surficial sediments were collected in 1968 and core sediments in 1976 from Lake Ontario. These were analysed for organochlorine insecticides and PCB. Residues of organochlorine compounds were higher in the three Ontario depositional basins than in sediment in the non-depositional zones. PCB was present at the highest concentration, with mean levels of 57 ppb for the whole lake. Residues of PCB in the three basins exhibited only minimal differences. ΣDDT was the second most frequently found contaminant. Both parent DDT and its two metabolites were present in sediment, giving a mean residue of 42.8 ppb for the whole lake. Differences in residues for the three basins were again minimal. DDT was present in sediments estimated to be deposited between 1958 and 1976. HEOD was present in only 40% of sediments and the mean residue for the whole lake was 0.6 ppb. The Niagara basin contained mean residues (1.4 ppm) of HEOD much above the other basins. Chlordane was virtually absent from the lake in the sediments collected in 1968 but appeared in cores between 1964-1976. Endosulfan appeared in lake sediments as a spill of deck cargo at a location in the Niagara basin. This spill dispersed with the current down the south shore to deposit in the Rochester basin.

Pesticide and industrial chemical residues at the mouth of the grand, Saugeen and Thames rivers, Ontario, Canada, 1981–85

Water samples collected at the river mouth of the Grand, Saugeen and Thames rivers between January 1981 and December 1985 were analyzed for 20 herbicides, 25 insecticides and 3 fungicides that had been used in the basins. Thirteen herbicides were identified in river water; these ranged from single events in one basin over the five years to those appearing in most water samples from all three basins. Atrazine was the most frequently found pesticide present at measurable levels in 375 of 440 samples (85%). The second most frequently found pesticide was 2,4-D which was identified in 78 of 447 water samples (17%). No fungicides were detected in river water and only single events of two organophosphorus insecticides occurred in 446 samples analyzed (diazinon and malathion). Organochlorine insecticides were identified from both present and past use patterns. Heptachlor expoxide appeared as a breakdown product from the use of chlordane. The order by pesticide group in decreasing loadings at the river mouth were triazine herbicides < chloroacetanilide herbicides < chlorophenoxy and chlorobenzoic acid herbicides < organochlorine insecticides. The highest loadings at the river mouth were for atrazine, which ranged from 0.1 to 8.2 metric tonnes per basin representing between 0.2 and 2.1% of that applied in the basin. Loadings of alachlor, metolachlor, and cyanazine represented up to 0.5 metric tonnes at the Thames river mouth, but negligible amounts for the other basins. Loading of chlorophenoxy herbicides and insecticides were infinitely lower than the triazines and chloroacetanilide herbicides. Some organochlorines of industrial origin were sought however, other than in 1981 when polychlorobiphenyls (PCBs) were present at measurable level; none were detected between 1982 and 1985.

Cadmium levels in Ontario moose and deer in relation to soil sensitivity to acid precipitation

This study examines the influence of buffering capacity of the soil on the levels of cadmium in the kidney, liver and muscle of moose and white-tailed deer from nine sampling sites (four buffered and five non-buffered) in Ontario, Canada. Tissues collected from hunter-killed moose and deer during 1984 and 1985 were analysed for cadmium. Tissue from moose in the non-buffered Algonquin Park site (21.9 +/- 1.1 mg/kg wet weight) and the buffered St. Joseph Island site (12.7 +/- 3.2 mg kg-1) had the highest mean levels of kidney cadmium compared with other sites sampled in Ontario. The highest mean levels of kidney cadmium in deer were found in the non-buffered Loring site (15.1 +/- 0.8 mg kg-1) adjacent to Algonquin. From all sites, the level of cadmium was highest in kidney, lower in liver and was often undetectable in muscle. Cadmium level increased with animal age (p less than 0.05). Levels of cadmium in Ontario moose from some regions are comparable to those found in Quebec and Manitoba and are considerably higher than those of Maine and Scandinavia. Levels of cadmium in kidneys and livers of white-tailed deer in parts of Ontario are considerably lower than those in Pennsylvania. As a result of this study, the Ontario Ministry of Natural Resources, in consultation with the Ontario Ministry of Health, has recommended that the public not consume kidneys or livers of Ontario moose and deer.

Investigations of pesticide contaminations in rural wells, 1979–1984, Ontario, Canada

Between the years 1979 and 1984, investigations were conducted into 311 events of suspected contaminations of wells with pesticides. This involved the analyses of water from 359 wells where the suspected contamination originated from (i) spills (ii) spray drift or (iii) surface runoff waters carrying pesticides into wells. Investigations covered 83 spill events involving 104 rural wells; tests revealed 79 of these became contaminated. The contaminations were caused by (i) spills of pesticide concentrates (ii) back-siphoning of spray solutions and/or (iii) spills from overfilling, emptying or rinsing spray equipment. The pesticides either entered directly into the wells or contaminated the area in the vicinity of the wells. In spite of cleanup attempts, difficulty was experienced in decontaminating most well waters and some had to be abandoned. The longest period of monitoring a contaminated well was 1, 117 days; during that time the decline in residue was slow.Investigations were made into 228 events involving 255 wells where spray drift and/or surface runoff waters with pesticides were observed as entering the well; however, only 55 were found to contain detectable residues. The highest proportion of these events was associated with surface runoff or spray drift from cornfields; of 86 wells involved only 26 contained measurable residues and all involved atrazine. Fifty-seven well investigations were associated with spraying right-of-ways and 16 waters were contaminated with 2,4-D and dichlorprop. The remaining 13 well contaminations were associated with various other land-use activities. It required 45 to 347 days to decontaminate these 55 wells.

Organochlorine and organophosphorus insecticides: Their use in eleven agricultural watersheds and their loss to stream waters in Southern Ontario, Canada, 1975–1977

Abstract As part of a comprehensive study of the effects of agricultural land use activities on the quality of water entering the Great Lakes, 949 stream water samples from 11 agricultural watersheds in southern Ontario were collected in 1975–1977 and analyzed for organochlorine and organophosphorus insecticide residues which were currently in use in those watersheds. Detectable residues of chlordane, heptachlor epoxide, and endosulfan were found in 1.6, 6.0, and 19.3% of samples, respectively. Over 50% of the total organochlorine insecticides were found to be transported in the January-to-April periods corresponding to spring thaws, low ground cover, and high suspended solids in the water. Unit area loadings ranged from 0 to 4.5 mg/ha/yr for chlordane plus heptachlor epoxide and 0 to 89.9 mg/ha/yr for endosulfan. Water quality objectives proposed by the International Joint Commission were exceeded in 4% of samples by heptachlor epoxide, and 14% of samples by endosulfan. Sixteen organophosphorus insecticides were known to be used in the watersheds but only chlorpyrifos, diazinon, ethion, and malathion were detected. Chlorpyrifos was present in only three samples, ethion in two, and malathion in four; 87 samples were found to contain diazinon but 64 of these were identified as originating from an indoor (non land-use) activity in one watershed. All field losses of organophosphorus insecticides occured in the May-August period correlating with the season of application. Proposed I.J.C. water quality objectives were exceeded in one sample where diazinon was used in land activities and in 77 samples as the result of diazinon being used in an indoor activity. No other organophosphorus insecticides were found which exceeded the proposed water quality objectives.

Triazine and chloroacetamide herbicides in Sydenham River water and municipal drinking water, Dresden, Ontario, Canada, 1981–1987

Samples of raw river water from the Sydenham River, Ontario were collected 30 to 50 times per year between 1981 and 1987 along with paired samples of drinking water from the town of Dresden. Atrazine and its metabolite, deethyl atrazine, were found in 89 to 100% of the raw water over the seven year period. Alachlor was found only in 1982, 1984 and 1985 when 2 to 17% of raw waters were contaminated. Cancellation of the registration to use alachlor at the end of 1985 resulted in no residues being found in 1986 and 1987. Cyanazine was found in 3 to 29% (1982–87), metolachlor in 19 to 27% (1984–87) and metribuzin in 2 to 7% (1982-86) of raw river water. Comparison of those residues in raw with those in drinking water revealed that chlorination of river water had no effect in reducing herbicide concentrations. During 1985 the addition of up to 50 mg/L of powdered charcoal to raw water reduced residues to near or below detection limits fors-triazine and Chloroacetamide herbicides. However, in 1986, with a reduced rate of 20 mg/L of charcoal herbicide residues were only slightly reduced and in 1987 with only 5 mg/L no reductions occurred.

Survey of farm wells for pesticides residues, Southern Ontario, Canada, 1981-1982, 1984

Water samples from 11 wells located in an area of intensive vegetable production on an organic soil were collected in 1981 and 1982, and analyzed for pesticide residues. Residues of diazinon, malathion, allidochlor, linuron, and prometryne were identified in four of the wells.Water samples from 91 wells were collected from farms on mineral soils across Southern Ontario during 1984 and analyzed for pesticide residues. Atrazine residues (0.1 to 74 μg/L) were present in 11 wells and trifluralin residues (41μg/L) contaminated one well. The highest residue of atrazine (74 μg/L) was present in one well along with contamination of three other herbicides and one insecticide. This was the result of a spill into the drilled well that gave residues of each component between 22 and 125μg/L. After 10 months of cleaning, this well was still contaminated.

Forestry workers involved in aerial application of 2,4-dichlorophenoxyacetic acid (2,4-D): Exposure and urinary excretion

Urinalysis was conducted on six volunteer workers involved in mixing and loading 2,4-D ester solutions into aircraft and in guiding the spray aircraft in two conifer release programs during 1981 and 1982. Exposures were reduced by wearing a full line of protective clothing. Two females and one male were involved in mixing the spray for 109 aircraft loads over an 11-day period in 1981. During the 1981 operation, the highest daily excretion of 2,4-D in the urine was 0.30, 0.94 and 9.59 μg/kg body weight for the three workers. In 1982, three male workers were involved, one diluting the concentrated solution and loading the aircraft, and two marking the swaths for aerial application over an 18 day period. The highest daily excretion of 2,4-D in the urine was 7.73, 8.37, 22.2 μg/kg body weight for the three workers. One of the authors, acting as a bystander, was directly sprayed in the 1982 season and 0.44% was absorbed based on urine analysis. The highest daily excretion of 2,4-D in his urine was 4.75 μg/kg body weight. For all seven people, the calculated exposure was less than the no-effect level of 10 mg/kg of body weight/day by a large margin of safety. The presence of 2,4-D in urine samples in the pre-spray period and its slow disappearance during the post spray period prompted further investigation. Swabs of internal surfaces of living quarters revealed deposits of 2,4-D from 0.7 to 288 μg/0.1m2 and on spray equipment from 0.7 to 184 μg/0.1m2.