污泥不同利用形式及利用量对土壤生态环境的影响

Effects of short-term land use of sewage sludge on soil environmental quality

为评估污泥短期土地利用对土壤环境质量的影响,对比分析了污泥堆肥、生污泥及化肥对照区土壤表层化学性质,土壤重金属含量差异,并利用潜在生态危害指数法对不同处理下土壤环境质量进行评价。研究结果表明:施用污泥堆肥和生污泥可以提高土壤氮磷及有机质含量,降低土壤pH值,对土壤全钾含量和盐分含量影响较小;与对照区CK相比,污泥土地利用各小区仅增加了土壤中汞含量,其余各重金属元素与CK差异不大,各处理重金属含量均在土壤环境质量II级范围内,污泥短期土地利用没有显著增加土壤重金属含量;污泥土地利用各小区潜在生态风险指数RI在64.63—127.11之间,部分处理土壤重金属污染达到中等污染,镉是主要的污染因子,其对潜在生态风险指数贡献比例达到31.73%—53.36%,其余重金属生态风险指数较低。

To assess the impact of short-term land use of sewage sludge on soil environmental quality, it comparatively analyzed the soil surface chemical properties and difference in soil heavy metal contents of sludge compost, raw sludge and fertilizers areas, and used the potential ecological risk index to evaluate soil environmental quality of different treatments. The results showed that raw sludge and sewage sludge compost increased soil nitrogen and phosphorus and organic matter content, reduced soil pH, and had less impact on the soil total potassium content and salt content. Compared with CK, treatments of sludge only increased mercury levels in soil, and other heavy metals contents were under the range of level II in the soil environment quality; short-term land use of sludge did not significantly increased the heavy metal content in soil. The potential ecological risk index（RI） of sludge treatments was 64.63-127.11; part of the soil heavy metal pollution was in medium pollution. Cadmium was a major pollution factor, and its contribution to the potential ecological risk index ratio reached 31.73%-53.36%; the ecological risk indexes of other heavy metals were low.