| Organochlorine pesticides (OCPs) and Polychlorinated biphenyls (PCBs) are environment typical Persistent Organic Pollutants (POPs). Although they has been banned for many years, they still were widely detected in the plants, animals, water, soil, sediment and other organisms due to refractory to highly chemical stability, biodegradation and long-term residual resistance to bioaccumulation along the food chain..Heavy metals are a kind of persistent toxic pollutants which can enter into the food chain cycle through soil, atmosphere and water, and other ways, causing harms to the organism and human health. The soil is the material basis of human survival, agricultural ecosystem carrier material and energy exchange. Heavy metals in soil and dust have many sources, primarily automobile exhaust, transportation, power plant emissions, industrial development, air pollution and other human activities.Therefore, the OCPs, PCBs and heavy metals residue analysis in soil, dust and corresponding plants contributed to reveal the deeper dynamics and pesticide contamination in the soil. So the environment risk assessment of OCPs, PCBs and heavy metals in soil are of great practical significance to the ecological environment. With the rapid industrialization, urbanization and population growth of Ulaanbaatar, more and more pollutants emits into the environment. Grassland soil in different areas of Mongolia and city park soil in Ulaanbaatar as the research object, the content of OCPs, PCBs and heavy metals were analyzed.In this study, we studied organochlorine pesticides, polychlorinated biphenyls and heavy metals in soil and dust of Ulaanbaatar city parks and different regions of Mongolia grassland soil. This studies the concentrations level of OCPs, PCBs and heavy metals. We also detected residual levels of typical organochlorine pesticides (HCHs and DDTs), PCBs and heavy metals using solvent extraction and gas chromatography equipped with electron capture detection (GC-ECD) method, choosing the city parks soil, pine needles and grassland soils as the research object. We studied typical organochlorine pesticides pollution status, source, and evaluated the environmental quality and ecological risks of Ulaanbaatar city parks and grassland. The main results were as follows:(1) The different parks soil of Ulaanbaatar, the content range of HCHs and DDTs were in range of11.36-53.14ng-g-1and11.96-24.70ng·g-1.The ratio of a-HCH and y-HCH ranged between0.2and3.6, o,p’-DDT and p,p’-DDT ranged between3and6. In park dust residual content of ΣHCHs and ΣDDTs were range of31.99-92.68ngg’and13.45-32.80ng-g-1. The o,p’-DDT/p,p’-DDT range between2.33and3.5. The park soil and dust mainly sources from industrial DDTs and use of dicofol. In different grassland soils of Mongolia, the residual content of ΣHCHs and EDDTs were range of19.50-105.55ngg-1and3.61-40.66ngg’,a-HCH and y-HCH ranged between0.3-1.0, o,p’-DDT/p,p’-DDT ratio higher than9.3. HCHs mainly source the use of lindane, DDTs was industrial DDTs and dicofol.(2) In Ulaanbaatar city park soil, dust and different grassland soil of Mongolia, the PCBs residues contents were in ranged from8.24to40.80ng-g-1,37.72to154.27ng·g-1and from10.88to33.73ng-g-1, respectively. The park soil, dust and grassland soils PCBs homologues to based PCB28, PCB52and PCB101. The main sources are used transformers, industrial waste, incinerator emissions and atmospheric pollution spread.(3) In pine needles collected from Ulaanbaatar city park, the content of HCHs and DDTs were ranged from2.7to90.76ng·g-1and from1.17to39.75ng-g-1. The ratio of a-HCH/y-HCH ranged between0.19and3, indicated the mainly sources of HCHs were possible origioned from industrial HCHs and lindane. The o,p’-DDT/p,p’-DDT ranged from0.8to7, which indicated the mainly sources of DDTs were dicofol and industrial DDTs.(4) We measured Cu, Pb, Zn and Cd concentrations of park soil and dust samples and different grassland soils. The concentrations of Cu, Pb, Zn and Cd in city park soil and dust in Ulaanbaatar were in range of15.22-23.57mg-kg-1,40.24-47.50mg·kg-1,64.42-92.84mg·kg-1,0.11-0.2mg-kg-1and13.87-41.87mg-kg-155.67-70.64mg-kg-1,107.03-234.90mg-kg-1,0.13-0.16mg-kg-1, respectively. The concentrations of Cu, Pb, Zn and Cd in different grassland soils of Mongolia were in range of2.78-23.88mg-kg-1,29.15-43.09mg-kg-1,30.71-85.85mg-kg-1and0.05-0.17mg-kg-1. The concentration of Pb, Zn, Cu and Cd were below Mongolian soil quality standard (MNS5850:2008) and second level of Chinese soil environmental quality standard (GB15618-2008). The potential ecological risk index showed that the park soils in Ulaanbaatar city and grassland soils in Mongolia were in light pollution. The Pb and Zn were medium pollution in dust, and traffic was the possible source. |
PDF Full Text Request