重庆西部农业区大气沉降特征及其对地表的影响

Atmospheric deposition characteristic and its influence on the earth surface in western Chongqing agricultural area

从2009年4月至2010年4月,在重庆西部农业区采集了50个大气干、湿沉降样品,分别测试干、湿沉降样品中K、Ca、Mg、N、P、S、Fe、As、Cd、Cr、Cu、Hg、Ni、Zn、Pb、B、Mo、Mn 18种元素的含量,计算各元素的年沉降通量。研究发现,重庆西部农业区各元素年沉降通量均低于重庆主城区和成都经济区。采用富集因子分析得出,S、Cd、N、Pb、P、Hg、Mo、Zn、Cr、As明显受人为活动影响,其中S、Hg、As、Pb是典型的燃煤元素,Cd、Cr、Zn主要来源于工业排放、汽车尾气等,N、P与农业施肥密切相关。相关性分析表明,大气沉降输入Hg引起土壤中Hg含量显著增加,大气沉降输入S引起地表水中SO2-4浓度显著升高。

50 samples of dry and wet atmospheric deposition were collected in western Chongqing agricultural area from April 2009 to April 2010. All samples were analyzed for the contents of 18 elements （K,Ca,Mg,N,P,S, Fe, As, Cd, Cr, Cu, Hg, Ni, Zn, Pb, B, Mo, Mn）. Annual deposition fluxes of these elements were calculated. The annu al deposition flux of each element in western Chongqing agricultural area was lower compared to Chongqing urban area and Chengdu economic area. According to enrichment factor analysis, it was concluded that S, Cd, N, Pb, P, Hg, Mo, Zn,Cr and As were significantly influenced by human activities. S, Hg, As and Pb were typical coal-fired elements. Cd, Cr and Zn were mainly from industrial emission or car exhaust. N and P were closely related to agricultural fertil- izer. Correlation analysis showed that Hg input from atmospheric deposition had caused significant increase of Hg content in the soil and S input had increased SO/24- concentration in surface water.