[Effects of heavy metals pollution on paddy soil aggregates composition and heavy metals distribution].
Topsoil samples were collected from a polluted and an adjacent non-polluted paddy field in the Taihu Lake region of China. Different particle size fractions of soil aggregates were separated by low-energy dispersion procedure, and their mass composition and Pb, Cd, Hg, and As concentrations were determined. Under heavy metals pollution, the mass composition of sand-sized fractions reduced, while that of clay-sized fractions increased. The concentrations of test metals in different particle size fractions differed, with the highest in < 0.002 mm fraction, followed by in 2-0.2 mm fraction. In 0.02-0.002 mm and 0.2-0.02 mm fractions, all the test metals were relatively deficient, with an enrichment index of 0.56-0.96. The present study showed that the aggregation of fine particles could be depressed by heavy metals pollution, which in turn, led to a relative increase in the mass composition of fine particles and the associated allocation of heavy metals in weakly aggregated silt particles, and further, increased the risks of heavy metals translocation from polluted farmland into water and atmosphere. Further studies should be made on the impacts of heavy metals pollution on soil biophysical and biochemical processes and related mechanisms.
Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095, China. zhangliangyun0305@126.com
Liang-Yun
LY
Zhang
Lian-Qing
LQ
Li
Gen-Xing
GX
Pan
Li-Qiang
LQ
Cui
Hong-Lei
HL
Li
Xiao-Yan
XY
Wu
Jie-Qi
JQ
Shao
D002681:China; D017753:Ecosystem; D004784:Environmental Monitoring; D019216:Metals, Heavy / Q000032:analysis*; D012275:Oryza / Q000254:growth & development*; D010316:Particle Size; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*
D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants