城市生活污泥中锌及病原物对作物及土壤环境的影响

Effect of Municipal Sewage Sludge Applied to Agricultural Land on Crop andSoil

本文通过２年田间试验研究表明，年施用近１５（干）ｔ／ｈａ（菜地）或１０（干）ｔ／ｈａ（粮田）城市生活污泥未发现对作物可食部分造成Ｚｎ、Ｃｕ、Ｐｂ、Ｃｄ及Ｎｉ等重金属污染，但Ｚｎ在作物体内有一定累积。施用污泥会导致Ｚｎ在土壤耕层中明显累积，并使耕层中呆积的锌有向下迁移的趋势。未经消化处理的污泥含相当数量大肠菌群及活的虫卵，但施用３个月后致死率达９０％－１００％。作者认为，污泥最好不用于蔬菜地上，而将污泥用于不进入食物链的园林绿地可能更安全可靠。

AbstractTwo year's field experiments and one year's lysimeter experiment withsoil column were conducted to study the impact of heavy metals and patho-gens,in sewage sludge on vegetable and cereal crops. The results showed that the edible tissues of plant were not polluted with Zn,Cu,Cd,Pb and Nifrom sewage sludge irrgated at a rate 15 dry metric ton ha￣(-1),yr￣(-1) for vegetable land or 10 dry metric ton, ha￣(-1),yr￣(-1) for ceredal land.Of five heavymetals,howerer,Zn concentration in crop had closest relation to applica- tion rates of sewge sludge,especially for foliar vegetables relative to cerealcrop. Besides,positive correlation between soil Zn concentration and app-lication rates of sewage sludge was also discovered.About 70% of sewagesludge-born Zn was retained in tillage layer of soil.Since sewage sludgehad markly effect in lowing soil pH,the Zn mobility in soil was enhanced,which resulted in Zn leaching to the depths of 60cm and 40cm in vegetablesoil and paddy soil,respectively,The impact of N P and heavy metalsfollowing successive application of sewage sludge for two years on under-ground water quality was not evident. Undegested sewage sludge contained a lot of pathogens such as E. Coli and ascarid eggs. Over three months after application of sewage sludge to agricultural land ,90% to 100%of E.coli was dead but sewage sludge should be stablized before use to preventfrom disease spread, Because sewage sludge had more negative effects on ve-getable soil than paddy soil,it 's suggested that sewage sludge should not be applied to vegetable soil.