施用生活污泥对滩涂土壤性质及重金属含量的影响

为了探讨应用生活污泥改良滩涂土壤的可行性，明确生活污泥对滩涂土壤理化性质及环境效应的影响，采用符合农用标准的城市生活污泥为材料，通过盆栽培养试验，研究了施用不同用量（0、2.5%、5%、10%、15%、20%，土壤、污泥均以干基计）的生活污泥对滩涂土壤性质及重金属含量的影响。结果表明，施用生活污泥可显著提高滩涂土壤的总氮、总磷、碱解氮、速效磷等养分含量，其中总氮、碱解氮增加的倍数很接近，速效磷增加的倍数远远高于全磷的增加倍数。施用生活污泥显著增加了滩涂土壤的有机质含量，降低了pH值，对土壤可溶性总盐含量无显著影响。施用生活污泥，增加了滩涂土壤Ni、Cd、Zn、Cu、Cr重金属的全量及有效态含量，在实际应用过程中应根据生活污泥重金属的含量确定施用量。

Effects of Sewage Sludge on Soil Properties and Heavy Metal Contents of Tidal Flat

In order to study the feasibility of improving tidal flat soil with the application of sewage sludge and to understand its effects on the physic-chemical properties of tidal flat soils and the environments, pot experiments were conducted to investigate the effects of sewage sludge on soil properties and heavy metal contents of tidal flat. Municipal sewage sludge meeting the standards for agricultural use were applied at dosages of 0, 2.5%, 5%, 10%, 15%, 20% of dry soil weight. The results showed that soil total nitrogen, available nitrogen, total and available phosphors, as well as organic matter were increased significantly. Total nitrogen and available nitrogen increased at same rates, while available phosphors increased at much higher rate than total phosphors. Soil organic content increased significantly with the use of sewage sludge, while soil pH decreased. No significant effect was observed on soil soluble total salt. Total and available contents of heavy metals in tidal flat, including Ni, Cd, Zn, Cu, Cr were significantly increased. Therefore, heavy metal contents in sewage sludge should be considered as an important criterion in practical use.