成都经济区天降水与下渗水元素地球化学特征及土壤元素输入输出通量

Geochemical characteristics and fluxes of elements in rain water and soil leaching water in the Chengdu economic region.

论文研究了成都经济区天降水和下渗水中元素含量、在农田耕层中的输入输出通量及其影响因素。研究表明，研究区雨水中含有大量SO4^2-、NO3^-等酸性物质，雨水中SO4^2-＞NO3^-＞Cl^-。雨水中Ca^2＋和NH4^＋含量最高，且NH4^＋＞Ca^2＋＞K^＋＞Na^＋〉Mg^2＋雨水的pH与阴、阳离子摩尔浓度差值具有显著相关性。下渗水中以Ca抖为主要阳离子，且Ca^2＋＞Na^＋＞Mg^2＋＞K^＋＞NH4^＋；HCO3^-为主要阴离子，且HCO3^-＞NO3^-＞SO4^2-＞Cl^-＞F^-，下渗水pH与阳、阴离子摩尔浓度差值具有显著相关性。不同地区雨水中Pb＞As＞Cd＞Se＞Hg，下渗水中Pb＞As＞Se＞Cd＞Hg，因此，Cd、Pb、Se和Hg等元素累积在耕层中，而As则被下渗水携带迁移出耕层进入地下水。由降雨输入土壤中的Cd通量均大于下渗水输出Cd的通量，局部地区As下渗通量高于雨水输入通量的5．45～13．16倍。土壤中元素的下渗比与土壤质地、pH有关。

In this paper, we have studied the element contents in rain water and soil leaching water, the output and input flux of farmland tilth and its influencing factors in the Chengdu economic region. The results show that the rain water in the study area contains a lot of acidic material such as SO4^2-, NOa, etc. , and SO4^2- NO3^-〉Cl^- by concentration. The concentrations of Ca^2＋ and NH^＋ are the highest, and NH4^＋〉Ca^2＋〉K^＋〉 Na^＋ 〉Mg^2＋ in the rain water. The pH of the rain water and the difference between anion and cation molar concentration are significantly correlated. By concentration, Pb〉As〉Cd〉Se〉Hg in the rain water and Pb〉As〉Se〉Cd〉Hg in leaching water in different areas; as a result, the element of Cd, Pb, Se, Hg, etc. are accumulated in tilth layer, and As was carried out from tilth layer into the underground by leaching. The Cd flux in the soil from the rain water is more than that from leaching; the leaching flux of As is 5.45 to 13.16 times higher than the flux from the rain water in some parts of the area. The leaching ratio of tilth elements is related to soil texture and pH value.