不同畜禽粪便好氧堆肥过程中重金属Pb Cd Cu Zn的变化特征及其影响因素分析

畜禽粪便中的重金属含量及其生物有效性是限制其农业利用的重要因素。采用好气模拟培养方法对6种畜禽粪便好氧堆肥过程中Pb、Cd、Cu、Zn的总量以及生物有效性动态变化进行研究探讨,并分析了影响重金属生物有效性的因素。结果表明,根据现有的国际以及我国农用污泥农用标准,某些粪便中存在着Cd、Cu、Zn含量超标,由于饲料受重金属污染的不同,造成不同畜禽粪便中不同的重金属含量差异性较大。堆肥过程中,由于挥发性物质的挥发作用,4种重金属含量均呈现增加现象,尤其是在0～14 d的堆肥中增加量最高;而生物有效性重金属占其全量重金属的比例呈现先增加而后下降的趋势,除仔猪粪外,堆肥均能降低重金属生物有效性部分的比例,这将有利于降低其农业利用的风险。温度和水溶性碳对堆肥过程中4种重金属的生物有效性部分重金属相对含量的变化有着显著的影响。

Dynamic Change Characteristic of Heavy Metals Pb, Cd, Cu and Zn During Aerobic Composting of Different Manure and the Analysis of Effect Factors

High total and bioavailable content of heavy metals in animal manures have become a major limiting factor for their land applica-tion in agriculture.Composting is the important disposal means to manure,so the change of heavy metals during composting should be further investigated.In the study,the dynamic change of total Pb,Cd,Cu,Zn contents and their relative bioavailable contents were investigated dur-ing aerobic composting of six manures including two chicken manures,three pig manures and a dairy manure.And the factors to affect the bioavailability of heavy metals were also analyzed.The results showed that Cd,Cu,Zn contents exceeded existing international standards and China′s agricultural sewage sludge in some animal manures.Total heavy metals contents increased during manure composting because of the volatilization of volatile substances of manure substance,especially during 0~14 d composting process due to higher substance volatilization than other composting phases.The relative bioavailable contents of four heavy metals firstly increased and then decreased during composting.In the end of composting,heavy metals bioavailability decreased expect for young pig manure,which will reduce the risk of its agricultural use.Through the correlation analysis,temperature and water-soluble carbon can affect the change of heavy metals bioavailability during ma-nure composting.