Organochlorine insecticides and PCB in the sediments of Lake Huron (1969) and Georgian Bay and North Channel (1973).

Surficial and core sediments were collected from the main body of Lake Huron in 1969 and Georgian Bay and North Channel in 1973. These were analysed for organochlorine insecticides and PCB. Residues of organochlorines were higher in the twelve depositional basins in Lake Huron and Georgian Bay than in sediment in the non-depositional zones. PCB was present at similar concentrations to sigma DDT; with mean levels of 13 and 10 ng/g for PCB and sigma DDT in the main body of Lake Huron and 11 and 5 ng/g for PCB and sibma DDT in Georgian Bay. Residues of PCB varied from 9--33 ng/g in the 12 basins. With respect to sigma DDT, both parent DDT and its two metabolites were present in sediment at a mean residue of 7.8 ng/g for the whole lake. The main lake had residues of 10.2 ng/g while Georgian Bay had 5.8 ng/g and North Channel 4.1 ng/g in keeping with use pattenrs since 1943. HEOD was present in only 5.7% of sediment samples from main Lake Huron, 30% from Georgian Bay and 15% from North Channel. The highest residues 1.7 ng/g occurred in the North Channel. No chlordane was detected, however, heptachlor epoxide was identified in 8.5% of sediments collected in Lake Huron, 23% from Georgian Bay and 14% in North Channel. Endosulfan appeared in 4% of samples from both Georgian Bay and North Channel.

Organochlorine Insecticides and Industrial Pollutants in the Milk Supply of Southern Ontario, Canada - 1977.

During the summer of 1977 milk samples were collected from 308 bulk transporters picking up milk in the southern region of Ontario. These milk samples were subjected to a comprehensive analysis for organochlorine insecticides and selected halogenated industrial pollutants. Ninety-five percent of samples contained residues of p,p'-DDE, dieldrin, heptachlor epoxide and PCB, 68% contained residues of HCB, and 16% contained residues of p,p'-DDE and p,p'-TDE; chlordane and endosulfan were detected in only a few samples. Residues of aldrin, endrin, lindane, methoxychlor, mirex, PBB and chlorinated phenols were not detected. Mean residues of insecticides in milk fat were ∑DDT, 0.015 ppm; dieldrin, 0.011 ppm; heptachlor epoxide. 0.002 ppm; endosulfan, 0.001 ppm; and chlordane, <0.001 ppm. Mean residues of industrial pollutants in milk fat were 0.033 ppm PCB and 0.002 ppm HCB. Compared with a similar survey conducted in 1973 for an approximately identical geographical area, levels of ∑DDT, PCB, and HCB showed a significant decrease. dieldrin showed only a slight decrease and heptochlor epoxide and chlordane increased. Reports are presented on individual case histories involving the misapplication of endrin, lindane, and fenthion to dairy cattle. The rate of elimination of these compounds from milk is presented.

Residues of organochlorine insecticides and polychlorinated biphenyls in fish from Lakes Saint Clair and Erie, Canada--1968-76.

Eighteen species of fish from Lake Saint Clair and 19 species from Lake Erie were analyzed for organochlorine pesticides and polychlorinated biphenyls (PCBs) between 1968 and 1976. Mean residues of sigma DDT peaked at 1.19 ppm in longnose gar (Lepisosteus osseus) caught in Lake Saint Clair in 1970-71, but had declined in all species by 1975-76. Dieldrin levels in fish tissues increased over the same period. White bass (Morone chrysops), caught in 1975 in Lake Erie, had the highest mean residue of dieldrin at 0.17 ppm. PCB residues increased in some species and decreased in others. PCB residues exceeding the tolerance level of Health and Welfare Canada were found in the following: from Lake Saint Clair, smallmouth bass (Micropterus dolomieui) in 1975 and channel catfish (Ictalurus punctatus) in 1971; from Lake Erie, coho salmon (Oncorhynchus kisutch) in 1970, smallmouth bass, alewife (Alosa pseudoharengus), freshwater drum (Aplodinotus grunniens), and gizzard shad (Dorosoma cepedianum) in 1971, and white bass in 1971 and 1976.

Residues of organochlorine insecticides and polychlorinated biphenyls in fish from Lakes Huron and Superior, Canada--1968-76.

Five species of fish from Lake Superior and 12 species from Lake Huron were analyzed for organochlorine pesticides and polychlorinated biphenyls (PCBs) between 1968 and 1975. Mean residues of sigma DDT peaked at 1.72 ppm and 7.60 ppm in lake trout (Salvelinus namaycush) from Lakes Superior and Huron, respectively. By 1975, the mean level of sigma DDT had decreased in lake trout and was highest in bloaters (Coregonus hoi) from both lakes: 1.06 ppm and 1.87 ppm, respectively. Dieldrin levels in fish from Lake Superior changed little over the same period. However, in 1969-70, dieldrin levels in fish from Lake Huron exceeded the 0.3 ppm tolerance level set by Health and Welfare Canada or the Food and Drug Administration, U.S. Department of Health, Education, and Welfare in 5 percent of lake whitefish (Coregonus clupeaformis) and 10 percent of bloaters. By 1975, 50 percent of bloaters caught in Georgian Bay and North Channel had dieldrin levels above 0.3 ppm. PCB residues declined in lake trout and lake whitefish caught in Lake Superior between 1971 and 1975, but increased slightly in bloaters and white sucker (Catostomus commersoni). Mean PCB residues in bloaters caught in Lake Huron in 1969-71 and 1975-76, and splake (Salvelinus fontinalis and S. namaycush) and cisco (Coregonus artedii) caught in 1975 exceeded the 2 ppm tolerance level.

Organochlorine poisoning of ring-billed gulls in southern Ontario.

Clinical, necropsy, bacteriologic, parasitologic, histopathologic, toxicologic and animal inoculation studies suggest that organochlorine (PBC, dieldrin and DDE) poisoning was an important factor in causing deaths of free-flying ring-billed gulls (Larus delawarensis) in southern Ontario in 1969 and 1973. The brains of gulls dying with clinical signs of neurologic involvement, and dead gulls with no other apparent cause of death, contained organochlorine residues of significantly greater levels than those found in healthy gulls shot for comparison.

Organochlorine and mercury residues in the harp seal (Pagophilus groenlandicus).

Samples of blubber, liver, kidney and brain, obtained from 10 male, 6 female neonatal, and 4 lactating female harp seals (Pagophilus groenlandicus), were analysed for DDT, dieldrin, PCB, and total mercury. Methyl mercury levels in blood were also determined. Biocide deposition was not significantly different in female and male ten day old pups. There were no significant differences in biocide levels in the liver of the 14/+ day old males, but in blubber there were significant differences in dieldrin and DDT. There was no clear relationship between biocide levels in the 6-18 year old lactating adults and their pups. Younger adult seals (6 and 7 years) were found to have higher levels of PCB and sigmaDDT levels in their blubber than did older females (10 and 18 years). Wide intraspecific variation was noted in organochlorine and mercury residue levels. Pups taken in 1973 were found to have lower organochlorine residues than pups taken in the same area in 1971. Preliminary investigation indicates that detectable amounts of organochlorine and mercury residues are capable of crossing the placenta in the harp seal.

Residue of organochlorine compounds and mercury in birds' eggs from the Niagara Peninsula, Ontario.

Eggs (307) were collected in 1971 from twenty species of birds with a variety of feeding habits from the Niagara Peninsula. This area of ontario is intensively developed for agriculture and heavy industry and has a large urban population. Representative species were obtained from both the terrestrial and aquatic food chains. Eggs were analyzed for organochlorine insecticides, polychlorinated biphenyls, and total mercury. Eggs from carnivorous species at the top of the aquatic food chain had the highest mean residues of signa DDT(7.6to 22.4 pm), PCB (3.5 to 74.0 ppm) and total mercury (0.64 to 0.83 ppm). Eggs from some terrestrial carnivores (red-tailed hawk and great horned owl) also had relatively high residues (2.5 to 3.9 ppm of sigmaDDT, 0.2 to 1.0 ppm of PCB, 0.06 to 0.09 ppm of mercury, however levels were much lower than those found in eggs from aquatic-feeding carnivores. Eggs from one red-shouldered hawk had residues comparable to the aquatic feeding carnivores. Eggs from herbivorous and insectivorous birds of both aquatic and terrestrial environments contained much lower residues. PCB residues were slightly lower in eggs among the terrestrial feeding species (0.05 to 2.0 ppm) than among the aquatic feeders (0.14 to4.0 ppm) and tended to be lower in eggs from terrestrial species collected in rural than incity environs. Levels of sigmaDDT were similar in both groups with eggs from terrestrial feeders containing mean resisues between 0.15 and 2.64 ppm and those from aquatic feeders between 0.33 and 2.79 ppm.