Insights into low fish mercury bioaccumulation in a mercury-contaminated reservoir, Guizhou, China.
We examined Hg biogeochemistry in Baihua Reservoir, a system affected by industrial wastewater containing mercury (Hg). As expected, we found high levels of total Hg (THg, 664-7421 ng g(-1)) and monomethylmercury (MMHg, 3-21 ng g(-1)) in the surface sediments (0-10 cm). In the water column, both THg and MMHg showed strong vertical variations with higher concentrations in the anoxic layer (>4m) than in the oxic layer (0-4 m), which was most pronounced for the dissolved MMHg (p < 0.001). However, mercury levels in biota samples (mostly cyprinid fish) were one order of magnitude lower than common regulatory values (i.e. 0.3-0.5 mg kg(-1)) for human consumption. We identified three main reasons to explain the low fish Hg bioaccumulation: disconnection of the aquatic food web from the high MMHg zone, simple food web structures, and biodilution effect at the base of the food chain in this eutrophic reservoir.
Institute F. -A. Forel, University of Geneva, route de Suisse 10, C.P. 416, CH-1290 Versoix, Switzerland. bl2444@columbia.edu
Bian
B
Liu
Haiyu
H
Yan
Cuiping
C
Wang
Qiuhua
Q
Li
Stéphane
S
Guédron
Jorge E
JE
Spangenberg
Xinbin
X
Feng
Janusz
J
Dominik
D000818:Animals; D002347:Carps / Q000378:metabolism*; D002681:China; D004784:Environmental Monitoring; D020387:Food Chain; D005618:Fresh Water / Q000032:analysis; D019015:Geologic Sediments / Q000032:analysis; D008628:Mercury / Q000032:analysis / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*; D014877:Water Pollution, Chemical / Q000032:analysis
D014874:Water Pollutants, Chemical; D008628:Mercury