[Human hair mercury levels and the influencing factors of the residents living in Qianguo Irrigation Area].

To understand the current mercury exposure level of the residents living within the Second Songhua River basin, 120 hair samples were collected from Qianguo Irrigation Area in the downstream of the basin. The total mercury contents in hair samples were determined and the influencing factors were analyzed. The results showed that the range of the total mercury contents was 0.15-1.01 mg/kg and the average value was 0.56 mg/kg. The average hair mercury content of male residents was 0.55 mg/kg while that of female residents was 0.60 mg/kg. The total hair mercury firstly increased and then gradually decreased with the increasing of age. The lowest mean hair mercury value(0.47 mg/kg) was detected in the residents with the age of 0-20 and the highest mean hair mercury value (0.73 mg/kg) was detected in the residents with the age of 40-50. Among the other factors influencing human hair mercury contents, the gender, height, body weight, fish consumption, smoking and wine-drinking showed no significant correlations with the hair mercury contents. Only one hair sample was detected with greater mercury content than the limitation (1.00 mg/kg) established by USEPA, suggesting low mercury exposure risks in the area. This investigation indicated the historical pollution of the Second Songhua River hadn't lead health risks to the residents of the region and the irrigation using water from the river after the building of the Hadashan Reservoir would cause low environmental risks.

[Quantitative characteristics and source analysis of heavy metals in paddy soils in downstream of the Second Songhua River, Jilin Province].

In autumn 2008, a total of 65 plough layer soil samples were collected from the paddy fields in Qianguo Irrigation Area located at the downstream of the Second Songhua River. These paddy fields were irrigated with water from the River, and had different irrigation histories. The Cu, Pb, Zn, Cd, Ni, As, and Hg concentrations in the soil samples were determined, and the accumulation characteristics, input approaches, and pollution sources of these heavy metals were analyzed. The Cu, Pb, Zn, Cd, Ni, As, and Hg concentrations in the samples were 14.1-28.4 mg x kg(-1), 37.6-57.4 mg x kg(-1), 53.3-84.4 mg x kg(-1), 0.044-0.367 mg x kg(-1), 18.4-37.0 mg x kg(-1), 3.25-12.11 mg x kg(-1), and 0.031-0.155 mg x kg(-1), respectively. The Pb, Hg, and Cd exhibited an obvious accumulation trend, with their concentrations being 100.0%, 38.7%, and 66.1% higher than the baselines, respectively, while Cu, Zn, Ni, and As had less accumulation. With the increase of irrigation history, the Pb concentration showed a decreasing trend, while the Hg concentration was in reverse. There was no significant correlation between the Cd concentration and the irrigation history. According to source analysis, soil Pb mainly originated from the atmospheric Pb deposition via historical use of leaded gasoline, soil Hg was from the polluted irrigation water from the Second Songhua River, and soil Cd was from the use of chemical fertilizers, pesticides, and other agrochemicals. Though the Pb, Hg, and Cd had obviously accumulated in the paddy fields in Qianguo Irrigation Area, their potential ecological risk was still low, and would not pose threat on the local agricultural production and food security.