Statistical Survey of Persistent Organic Pollutants: Risk Estimations to Humans and Wildlife through Consumption of Fish from U.S. Rivers

U.S. EPA conducted
a national statistical survey of fish tissue
contamination at 540 river sites (representing 82 954 river
km) in 2008–2009, and analyzed samples for 50 persistent organic
pollutants (POPs), including 21 PCB congeners, 8 PBDE congeners, and
21 organochlorine pesticides. The survey results were used to provide
national estimates of contamination for these POPs. PCBs were the
most abundant, being measured in 93.5% of samples. Summed concentrations
of the 21 PCB congeners had a national weighted mean of 32.7 μg/kg
and a maximum concentration of 857 μg/kg, and exceeded the human
health cancer screening value of 12 μg/kg in 48% of the national
sampled population of river km, and in 70% of the urban sampled population.
PBDEs (92.0%), chlordane (88.5%) and DDT (98.7%) were also detected
frequently, although at lower concentrations. Results were examined
by subpopulations of rivers, including urban or nonurban and three
defined ecoregions. PCBs, PBDEs, and DDT occur at significantly higher
concentrations in fish from urban rivers versus nonurban; however,
the distribution varied more among the ecoregions. Wildlife screening
values previously published for bird and mammalian species were converted
from whole fish to fillet screening values, and used to estimate risk
for wildlife through fish consumption.