Concentration, Profiles And Assessment Of New Pesticide Pops In Typical Contaminated Sites And Its Nearby Environments

With the enrichment of persistant organic pollutants(POPs) in the Stockholm convention list, contaminated sites concerning these pollutants are increasing. China, as a large pesticide production and usage country, there has been numerous contaminated sites, and environment pollution from these kinds of pollutants can be more serious. It is of great significance to investigate the concentrations and distribution characteristics of these pollutants in POPs contaminated sites and its nearby environments. And on this foundation, conducting all-sided assessment will provide data basis for environmental management.In this study, 2 typical contaminated sites(in urban areas) for newly updated POPs were selected for investigation, one for HCHs and the other for Endosulfan. Concentrations, profiles and distribution characteristics were determined in soils(both surface and deep soil), atmosphere, ground water and plants. As for the nearby environment, soil, atmosphere and local crops were researched in this paper. And last but not least, risk assessments were conducted both in and nearby the contaminated sites.The main results are as follows:1.The ΣHCHs(sum of α-,β-,γ-,δ-HCH) concentrations in surface soil of Chongqing A plants range from 2.0~148.5 mg/kg, while the deep soil is 0.05~21.27 mg/kg, the detection rate of the four isomers of HCHs is 100%. In the vertical direction, the highest concentrations of HCHs were found in the depth of 1 m with a fluctuation trend under the ground, while in the deeper place, HCHs in soil is rapidly reduced. For the atmosphere, the HCHs were detected to be 10.2~132.8 ng/m3,and the highest concentration was found in the soil of the waste storage area. HCHs in underground water was found to be 1.4~2.6 μg/L, all under the third standard of the underground water quality standard(GB/T14848-93).In the plants growing in the contaminated sites, higher HCHs were found to be 24.6~520.7 ng/g d.w..2.In the environment medium around the Chongqing A pesticide sites, the HCHs were widely detected in the soil, atmosphere and crops, with the concentrations as 46~665 ng/g, 1.52~13.79 ng/m3 and 3.71~85.1 ng/g f.w., HCHs levels in the environment medium around the site reduce with the distance to the site, and in the samples 2.0km distant to the plant, the HCHs level have a wave peak, and then reduced rapidly. HCHs residues detected in vegetables are all below the MRLs set by the Chinese standards(GB2763-2014) except a cowpea sample.3. In the contaminated site for endosulfan, higher concentrations were found centralized around the area of endsulfan emulsion workshop(S5), which reached 47.6 mg/kg, while compared with this peak value, concentrations of endosulfan in other area of the plant were quite lower, which ranged from 0.09 to 2.85 mg/kg. In the vertical direction, endosulfan was found to be 0.01 ~ 114 mg/kg, high concentrations of endosulfan around the emulsion workshop may be due to the release of transportation and the pouring of waste water containing endosulfan, and the accumulation capability of the soil.4. In the environment medium around the Jiangsu B pesticide sites for endosulfan, concentrations were detected in the soil, atmosphere and crops, with the concentrations as 1.37~53.57 ng/g, 0.89~10.36 ng/m3 and 4.09-119.2 ng/g d.w., endosulfan levels in the environment medium around the site reduce with the distance to the site, and a wave peak was found in the samples 2.0km distant to the plant. In the atmosphere, upwind direction showed lower endosulfan concentrations comparing to the samples from downwind direction. The detection rate of endosulfan residues in crops is 100%.5. Through risk assessments, the cancer risks of HCHs in the contaminated site are generally high, exceeding our country’s acceptable level(<10-6), while the hazardous index is under the acceptable level(<1).As for the nearby environment medium, the cancer risks and the hazardous index are all acceptable except two area, whose cancer risk is over the limits. For the endosulfan, the hazardous index of contaminated site and its nearby environments are all below the acceptable level except one point, the endosulfan emulsion workshop in the site. During the assessment nearby the plants, children, as a sensitive group, risks were found higher than adults.