Dt. Zaranko et al., BIOMAGNIFICATION OF POLYCHLORINATED-BIPHENYLS THROUGH A RIVERINE FOOD-WEB, Environmental toxicology and chemistry, 16(7), 1997, pp. 1463-1471
From 1989 to 1993, biota collected from Pottersburg Creek, London, ON,
Canada were analyzed for total polychlorinated biphenyls (PCBs) and l
ipids. Data were analyzed by analysis of covariance (ANCOVA) with lipi
d as the covariate, to investigate station, time, and trophic effects
on PCB accumulation in aquatic organisms. All three variables were hig
hly significant (p < 0.0001). PCB concentrations in biota decreased al
ong the length of the creek away from the point source. PCB concentrat
ions in biota collected in July 1993 were not significantly different
from concentrations in biota collected in July 1990 (p > 0.16), sugges
ting that sources into the creek have not been alleviated. The relatio
nship between PCBs and lipid for biota from Pottersburg Creek suggests
that organisms accumulate PCBs relative to their position in the food
web (p < 0.0001). Fish and leeches occupying the top of the food web
accumulated more PCBs than organisms occupying a lower trophic positio
n (crayfish and oligochaetes/ chironomids), indicating that biomagnifi
cation through trophic transfer (i.e., the uptake of a chemical throug
h ingestion) is the primary mechanism governing contaminant levels in
biota and not bioconcentration (i.e., the uptake of a chemical from wa
ter).