Quinton John N, Catt John A
Department of Environmental Science, Lancaster University, Lancaster, LA1 4YQ, UK.
Environ Sci Technol. 2007 May 15;41(10):3495-500. doi: 10.1021/es062147h.
Heavy metal pollution of soil and water is often associated with industry, but in this paper we demonstrate that water erosion on agricultural soil which has received only agrochemicals has enriched sediment metal concentrations to toxic levels which breach many accepted standards for soils and sediments. Eight 0.1 ha erosion plots with different cultivation treatments were monitored over a 6 year period for surface runoff, soil loss, and Cr, Cu, Pb, and Ni concentrations. Mean concentrations of these heavy metals were up to 3.98 times higher in the sediment than in the parent soil and in some erosion events the sediment had 13.5 times the concentration of metals in the soil. All the sediment heavy metal concentrations were significantly correlated (p < 0.01) with the clay and silt sized fractions of the sediment and with carbon content. The erosion was a highly selective process enriching the detached material in silt, clay, and organic carbon. This was particularly true in smaller erosion events. Sediment metal concentrations tended to follow the shape of runoff hydrographs, although the pattern changed from storm to storm.
土壤和水体的重金属污染通常与工业活动有关，但在本文中我们证明，仅施用了农用化学品的农业土壤遭受水蚀后，沉积物中的金属浓度已富集到有毒水平，超过了许多公认的土壤和沉积物标准。在6年时间里，对8个面积为0.1公顷、采用不同耕作处理的侵蚀地块进行了监测，以获取地表径流、土壤流失以及铬、铜、铅和镍的浓度数据。这些重金属在沉积物中的平均浓度比母质土壤高出3.98倍，在某些侵蚀事件中，沉积物中的金属浓度是土壤中金属浓度的13.5倍。沉积物中所有重金属浓度均与沉积物中的粘粒和粉粒级分以及碳含量显著相关（p < 0.01）。侵蚀是一个高度选择性的过程，使分离出的物质富含粉粒、粘粒和有机碳。在较小的侵蚀事件中尤其如此。沉积物金属浓度往往与径流过程线的形状一致，尽管每次暴雨的情况有所不同。
