Contamination levels of PCBs, and of the heavy metals
cadmium (Cd), lead (Pb) and mer
cury (Hg) were analyzed in four fish spe
cies from seven rivers in the North of Luxembourg. During August and September 2007, 85 samples of fish were
colle
cted belonging to four spe
cies: the stone loa
ch (Barbatula barbatula, n = 12 pools), the
chub (Squalius
cephalus, n = 36), the barbel (Barbus barbus, n = 23) and eel (Anguilla anguilla, n = 14). The
con
centration of seven indi
cator PCBs (∑
7PCBs) rea
ched a mean of 39 ng g
−1 and varied between 4.0 and 346.2 ng g
−1 (wet wt) depending on the site and spe
cies. Fish
colle
cted at Wallendorf on the Our River and sites on the Wiltz and the Clerve rivers showed the highest
con
centrations for PCBs. In
comparison with 1994, PCB levels in fish de
creased strongly during the last de
cade in these rivers. Lead was dete
cted at low levels (0–181.4 ng g
−1 wet wt). Mer
cury
con
centrations ranged between 10.3 and 534.5 ng g
−1 (wet wt) ex
ceeding maximum tolerable levels for human
consumption of 500 ng g
−1 in two fish out of 85. Chubs and eels from the Sûre River were the most
contaminated by mer
cury. Cadmium levels varied between 4.0 and 103.9 ng g
−1 (wet wt). In addition to mer
cury in fish,
cadmium was the most problemati
c pollutant on the Our, the Wiltz, the Clerve and the Troine Rivers, be
cause values found in 20 % of fish ex
ceeded the threshold of about 10–50 ng g
−1 (wet wt) re
commended for human health.
The total PCB level predicted to accumulate in livers from otter potentially feeding on these fish based on a previously published mathematical model is 37.7 ;c;g g−1 (lipid wt), which is between a proposed ȁc;safe level” and a ȁc;critical level” for otters. Rivers in the North of Luxembourg are thus to some extent polluted, and the establishment of otter populations could be affected by current levels of contamination.