中国华北和华南典型城市和农村站点降水化学特征

Chemistry Character of Rain Water at Urban and Rural Areas in the North and Southeast of China

分别在位于中国北方的北京和山东泰安郊区的马庄,以及南方的深圳和福建南平的郊区茫荡山对降水进行了采集,测定了其pH值、电导率和化学成分。北京、泰安马庄、深圳和南平茫荡山降水的pH值分别为6.02,5.97,4.72和4.81。北方降水污染严重,南方降水污染较轻但雨水酸度较高。SO24-,NH4+,Ca2+和NO3-是各地降水中主要离子组分,不论是北方还是南方的降水中SO24-仍然是主要的致酸因子,NH4+都是最主要的中和物质。应用富集因子法比较了不同地区海洋源、地壳源和其他来源对降水组分的贡献。应用后向轨迹横式分析了不同输送路径的降水化学特征,泰安马庄降水受不同路径的传输影响显著,深圳和茫荡山降水受其影响较小。

Samples for rain water were collected at four sites including Beijing city and Mazhuang Town in the north of China and Shenzhen city and Mangdang Mountain in the southeast of China. The pH values of precipitation, values of conductivity and concentrations of major water soluble ions were measured. The pH values of rainwater in Beijing City, Mazhuang Town, Shenzhen City and Mangdang Mountain were 6.02, 5.97, 4.72 and 4.81, respectively. The most abundant ions in the rainwater included NH4^＋ , Ca^2＋ , SO4^2- and NO3^-. SO4^2- was still the major acid ion in rain and NH4^＋ was the most important neutralizing ion at these four sites. While the rainwater in the north of China was more severely polluted than that in the south, the acidity of the rain was greater in the south than that in the north. Enrichment factor was used to analyze the contribution from sea-water, soil and other sources to rainwater. Hysplit 4.7 Model was used to indicate different chemical characters among different backward trajectories. The chemical characters of rainwater in Mazhuang Town were distinctly different among different trajectories and it was not significant among different trajectories in Shenzhen City and Mangdang Mountain.