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MA-100
--- Abstract
Organochlorine
Compounds in Fish Tissue from the Connecticut, Housatonic, and
Thames River Basins Study Unit, 1992-94
Water-Resources
Investigations Report 98-4075
By
James F. Coles
Organochlorine
compound concentrations were assayed in the tissues of fish
collected at 32 sites in the Connecticut, Housatonic, and Thames
River Basins study unit during 1992–94. The study was part of a
survey of organic and inorganic contaminants in biological
tissues, a component of the U.S. Geological Survey’s National
Water Quality Assessment (NAWQA) program. Concentrations of 28
organochlorines were measured in composite samples of whole fish
collected at the sites. The organochlorine compounds most commonly
detected in the tissue samples were total DDT (sum of o,p'-
and p,p'-DDD, DDE, DDT), total chlordane (sum of cis- and trans-chlordane, cis‑ and
trans-nonachlor, oxychlordane, and heptachlor epoxide), and total
PCBs (Aroclors 1242, 1254, and 1260).
At
31 sites, at least one component of total DDT was detected in fish
tissue at concentrations greater than the method reporting limit
of 5 micrograms per kilogram of wet weight. The highest
concentration of total DDT detected in fish tissue was 300
micrograms per kilogram. Although total DDT was detected at all
but one site, concentrations were lowest in
areas of low population densities. The DDT metabolite p,p'-DDE
was detected most frequently and at the highest percentage of
all DDT components, possibly indicating that DDT inputs into the
aquatic system were not recent. At 25 sites, at least one
component of total chlordane was detected in fish tissue at
concentrations greater than the reporting limit of 5.0 micrograms
per kilogram. The highest concentration of total chlordane
detected in fish tissue was 390 micrograms per kilogram.
Concentrations of
the total chlordane in fish tissue showed a strong positive
correlation with the drainage basin population density for a site,
supporting the premise that chlordane was used extensively in
suburban and urban areas before its use was restricted. Of the
components comprising total chlordane, trans-nonachlor
(the least degradable component) was detected most frequently and
at the highest concentrations, indicating that chlordane inputs
into the aquatic system were not recent.
At 28 sites, total PCBs were detected in fish tissue at concentrations
greater than the method reporting limit of 50 micrograms per
kilogram of wet weight; the highest concentration measured was 72,000
micrograms per kilogram. Concentrations of total PCBs generally
were high in fish from the largest rivers; the highest
concentrations were in tissures of fish from the Housatonic River;
concentrations in tissue samples from three sites exceeded 10,000
micrograms per kilogram. Although most PCBs in the Housatonic
River are from a documented source, high concentrations of total
PCBs at other large river sites probably originate in the urban
and industrial areas along these rivers.
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