重庆主城大气降尘中重金属污染特征及评价

为了解重庆主城大气降尘中重金属的污染特征及风险，于2017年12月至2018年11月，逐月监测了郊区、文教区和居住区等6个功能区的大气降尘，用AAS分析了其中Cd、Cr、Ni和Pb的含量，并结合潜在生态风险指数法和地累积指数法对降尘中的重金属污染进行了评价.结果表明，大气降尘中Cd、Cr、Ni和Pb含量（mg·kg^-1）和沉降通量［mg·（m²·a）^-1］分别为1.59和0.39、72.68和8.04、20.99和2.41、101.17和10.41，各功能区大气降尘秋季重金属含量显著高于其他3个季节，而各功能区的大气这4种重金属降尘通量总体表现为冬季显著低于其他3个季节.潜在生态危害指数和地累积指数显示，Cd有极高的生态危害和较高的污染，Cr、Ni和Pb造成的生态危害低，且污染也较低，工业居住混合区和交通枢纽具有高生态危害及较高的污染，郊区的生态危害和污染都相对较低.

Pollution Characteristics and Assessment of Heavy Metals in Atmospheric Deposition in Core Urban Areas,Chongqing

Pollution characteristics and risk of heavy metals in atmospheric deposition in core urban areas of Chongqing were investigated for one year from December 2017 to November 2018.Six functional zones:suburb, education area, residential area, commercial area, transportation hub, and industrial-residential area in Chongqing were selected for monthly atmospheric deposition collection. Concentrations of Cd, Cr, Ni, and Pb were analyzed using AAS. The potential ecological risk index and geoaccumulation index were used to evaluate the heavy metals pollution. Results show that the concentrations of Cd, Cr, Ni, and Pb in the atmospheric deposition were 1.59, 72.68, 20.99, and 101.17 mg·kg^-1, respectively, and their annual deposition fluxes were 0.39, 8.04, 2.41, and 10.41 mg·(m²·a)^-1, respectively. Concentrations of heavy metals in autumn were significantly higher than those in the other three seasons, especially for Cd, and their deposition fluxes in winter were lowest. The potential ecological risk index of Cd was biggest, achieving a very high ecological hazard level, while the ecological risk of Cd and Pb in industrial-residential area was highest, and that of Cr and Ni, respectively, were highest in transportation hub and residential area. The geoaccumulation index indicated that the pollution of Cd was the highest, and that of Cr, Ni, and Pb was very low. The pollution in industrial-residential area and transportation hub was high, while that in the suburb was relatively low.