[Mercury speciation transformation in soil of the water-level-fluctuating zone in the Three Gorges area under alternative dry-wet condition].
The speciation transformation, influencing factors, as well as bioavailability of mercury (Hg) in soil of the water-level-fluctuating zone in the Three Gorges Reservoir Area were simulated. The results showed that Hg in soil under alternative dry-wet condition could be transformed and released. The total Hg content in the soil was decreased by 28.9% after two "wet-dry" cycles. The percentages of the six Hg species (water-soluble, exchangeable, carbonate-bound, humics-bound, organic-sulf and residual Hg) were 6.1%-16.8%, 5.8% -12.9%, 4.5%-17.7%, 12.5%-29.9%, 5.3%-12.8%, and 34.5%-51.6%, respectively. It was found that Hg in soils was dominantly residue Hg, whose percentage tended to decrease under alternative dry-wet condition. The percentage of humics-bound Hg increased gradually and an increase of the percentage of bioavailable Hg (including water-soluble, exchangeable, carbonate-bound, and humics-bound Hg) after two wet-dry cycles were observed. Bioavailable Hg could be easily absorbed by aquatic organisms to enter the food chain, which might increase the ecological risk of Hg in the reservoir.
Cheng
C
Zhang
Li
L
Song
Ding-Yong
DY
Wang
Jin-Yang
JY
Zhang
Rong-Guo
RG
Sun
D001682:Biological Availability; D002681:China; D008628:Mercury / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D014867:Water
D012987:Soil; D012989:Soil Pollutants; D014867:Water; D008628:Mercury