Residues of PCB's and DDT in the western Lake Superior ecosystem

Abstract

Fish from western Lake Superior (1972-73) contained DDT and PCB residues at concentrations greater than o.1 ppm. The most predominant PCB's were those containing 3 to 6 chlorine atoms per molecule, and GLC data indicated that the mixtures were most like the commercial product Aroclor 1254(2). Other chlorinated contiminants identified by GC/MS analyses and occurring at concentrations less than 0.1 ppm were hexachlorobenzene (C6Cl6), chlordane, nonaclor, and dieldrin. Lindane, which has been previously reported in Lake Superior, was below the detection limit of approximately 0.01 ppm. The relationship between the size of lake trout and the concentration of total DDT in the fish was compared to measurements reported in previous studies. The comparison suggests that DDT residues have declined since 1968. The concentration of PCBs was estimated to be 0.8 ng/L in Lake Superior water and 0.1 ppm in large zooplankton. The apparent bioconcentration factor for PCBs in Lake Superior fish ranged from 10(5) to 10(6). The concentration of total DDT and PCBs in the larger Lake Superior fish exceeded the 5 ppm tolerance level established by the U.S. Food and Drug Administration for these chemicals in fish tbe used for human consumption.

Accumulation of polychlorinated biphenyls (PCBs) in surficial Lake Superior sediments. Atmospheric deposition

“…The arithmetic mean concentration of 0.17 µg of PCB per g of sediment exceeds by 2 to 10 times the values of 0.06 and 0.007 µg of PCB/g observed for sediments in Lake Superior by Glooschenko et al (11) and Veith et al (12), respectively. This may be attributed in part to the superior sampling capabilities of the box corer used in this study.…”

“…The atmosphere is likely to be the major source of PCBs to Lake Superior, since the lake has a large surface area compared to its drainage basin, has minimum tributary inflow, lacks industrial and urban activity in the basin, and greater than 50% of total water budget occurs in the form of rain. Although recent studies (1,4,11,12) indicate the PCB concentrations in certain commercial fish species are approaching or are greater than the FDA action limit of 5 pg/g, the water concentrations remain at or below detection levels (12).…”

Occurrence and bioaccumulation of organochlorine compounds in fishes from Siskiwit Lake, Isle Royale, Lake Superior

“…The difference in contaminant concentration between water and fishes provides an indication of the bioavailability of these compounds. Although numerous data bases exist on organic compound concentrations in Great Lakes fishes (1)(2)(3)(4)(5)(6)(7)(8)(9), few data are available for more remote regions.…”

“…The lake is a recharge lake with no inflow from Lake Superior. Our intent was threefold: (1) to evaluate the extent of contamination by these compounds in a remote lake system as indicated by concentrations of contaminants in fish, (2) to assess the relative bioavailabilities of these compounds by looking at species differences and age differences within species, and (3) to determine the relationship of bioconcentration factor (BCF) and octanol-water partition coefficient (Kow) and to compare these data to bioaccumulation models. Because Table I.…”

Putting science into persistence, bioaccumulation, and toxicity evaluations

“…During the late 1970s and early 1980s, much effort was devoted to the study of PCB behavior in the Great Lakes. At the same time, these compounds were being found in unexpected places far from sources such as western Lake Superior [20–22] and the marine Arctic ecosystems [23–25]. Atmospheric transport was clearly identified as playing a key role [26,27].…”