Relationships between humic substance-bound mercury contents and soil properties in subtropical zone.
The bioavailability of humic substance-bound mercury (HS-Hg) has been established, while the distribution of HS-Hg in soils in relation to soil properties remains obscure. Path analysis and principal component analysis were employed in present study to investigate how soil factors influence the contents of HS-Hg in soils. Results showed that HS-Hg ranged from 0.0192 to 0.2051 mg/kg in soils. The two fractions existed in soils as humic acid-bound mercury (HA-Hg) > fulvic acid-bound mercury (FA-Hg) and the ratio of HA-Hg/FA-Hg was 1.61 on the average. Soil organic carbon (OC) and HS favorably determined soil HS-Hg and the two fractions. The mercury source forming HS-Hg derived from soil total mercury and HS-Hg. FA-Hg and HA-Hg served as mercury source for each other. In acidic soils, FA-Hg and HA-Hg consistently rose with the increase of OC, and generally HA-Hg increased more dramatically. Soils with lower pH and lighter texture contained more HS-Hg, particularly fraction of FA-Hg. Among all influencing factors, organic material source showed the strongest effect, followed by other soil properties and soil mercury source.
Yu
Gui-fen
GF
Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. gfyu@issas.ac.cn
Wu
Hong-tao
HT
Jiang
Xin
X
He
Wen-xiang
WX
Qing
Chang-le
CL
D001578:Benzopyrans / Q000032:analysis; D006812:Humic Substances; D008628:Mercury / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D014329:Tropical Climate
D001578:Benzopyrans; D006812:Humic Substances; D012989:Soil Pollutants; D008628:Mercury; C005023:fulvic acid