贵州省污水处理厂污泥中重金属形态分布及其潜在生态风险评价  

Fractionation and Environmental Assessment of Heavy Metals in Sewage Sludge from Municipal Wastewater Treatment Plants of Guizhou Province

作　　者：文竹 李江[1,2] 王兴 张青青[2] 

机构地区：[1]贵州工程应用技术学院,贵州毕节551700 [2]贵州大学资源与环境工程学院,贵阳550025

出　　处：《中国农村水利水电》2016年第12期67-73,78,共8页China Rural Water and Hydropower

基　　金：贵州省科技厅课题"贵州省城市污水处理与防治技术探讨"(GZ20140230);贵州省高校创新课题"城市重金属防治研究(K052836)"

摘　　要：通过现场调查采样及室内分析,采用ICP-MS和修正的BCR法研究了贵州省污水处理厂污泥中重金属(Mn、Cu、Zn、Pb、Cr、Ni、As和Cd)污染状况及其分布特征,并利用综合污染指数法(Nemerow)和地累积指数法(Igeo)对重金属污染及其潜在生态风险进行综合评价。研究结果表明:贵州省污水厂污泥呈现高有机质、高氮的特点,具有较好的土地利用价值,8种重金属元素平均含量的大小顺序为Mn>Cu>Zn>Pb>Cr>Ni>As>Cd,其中Mn和Cu所占比例最高,Cd所占比例最小。相关分析可知,贵州省污水处理厂污泥有机质含量与各重金属含量均呈显著或极显著正相关,由此表明有机质含量是决定贵州省污水处理厂污泥重金属含量的主要因素。贵州省污水处理厂污泥Cu和Cr主要以酸溶可交换态形式存在,Pb和Cd以水溶态形式存在,As和Zn则主要是以可氧化态和可还原态存在,Ni较均匀地分布于不同形态(水溶态T1、酸溶可交换态T2、可还原态T3、可氧化态T4和残渣态T5);其生物活性系数大小依次为Ni>Cu>Mn>Cr>As>Zn>Cd>Pb,表明Cu、Ni表现出相对较高的不稳定性和可利用性,而Pb、Cd在污泥中稳定性较好,生物可利用性较低。贵州省污水处理厂污泥Cr、Ni、As单因子污染系数均值均小于1,属于低污染水平;污染系数均值由大到小依次为Cd>Pb>Cu>Mn>Zn>Cr>Ni>As。贵州省各城市污水厂污泥中重金属危害指数(Ei)基本表现为:Cd>Pb>As>Ni>Mn>Zn>Cu>Cr,其中毒害性最强的是Cd,其他城市各重金属污染处于低污染水平,复合生态危害指数(RI)大小依次为铜仁>贵阳>兴义>遵义>凯里>六盘水>毕节;Cu和Zn地累积指数较低,表现为轻度污染,而其他重金属的地累积指数较高,各城市之间的地累积指数差异较大,从均值来看,Cu、Ni、As和Zn属于轻度污染,Cr和Mn属于中度污染,Pb和Cd属于重度污染。On the basis of field investigation and laboratory analysis of municipal wastewater treatment plants of Guizhou, a survey of monito- ring the contamination levels of heavy metals （ i.e., Mn, Cu, Zn, Pb, Cr, Ni, As and Cd） by ICP-AES and modified BCR method, and their potential ecological risks are evaluated by Hakanson method in sludge. The results indicate that The physical and chemical properties of sewage sludge has high organic matter, nitrogen, phosphorus and potassium, which is of great value of land use. The content of Mn and Cu of sewage sludge has the highest percentage of total heavy metals, and Cd has the lowest percentage which orders Mn〉Cu〉Zn〉Pb〉Cr〉Ni〉As 〉Cd. Correlation analysis shows that organic matter and total nitrogen have positively correlated with heavy metals in sewage sludge frommtmicipal wastewater treatment plants of Guizhou （p〈0.05）, which are the main factors of the distribution of heavy metals. The content of Cu and Cr exists in the form of acid soluble state with organic combination, Pb and Cd in water soluble form, As and Zn are mainly in oxidation state and reduction state, Ni is evenly distributed in five kinds of forms. Its biological activity coefficient orders Ni〉Cu〉Mn〉Cr〉As〉Zn〉Cd〉 Pb〉Cu, which shows Cu and Ni have a relatively high instability and availability, while Pb and Cd have a good stability, low biological a- vailability. The research assesses the sludge with Hakanson ecological risk assessment method, and the results show that the Eir of heavy met- als in sewage sludge from municipal wastewater treatment plants of Guizhou show Cd〉Pb〉Cu〉Mn〉Zn〉Cr〉Ni〉As, and the Cr, Ni, As are low pollution with the Eir〈 1, and Ei ordered Cd〉Pb〉As〉Ni〉Mn〉Zn〉Cu〉Cr, among which Cd is the most toxic, RI orders Tongren〉Guiy- ang〉Xingyi〉Zunyi〉Kaili〉Liupanshui〉Bijie. Cu and Zn have a lower lgeo index with low pollution. Considered from the mean value, Cu, Ni, As and Zn belong to the mild pollution, Cr and Mn belong

关 键 词：贵州省 城市污泥 重金属 生态风险 

分 类 号：TV213.4[水利工程—水文学及水资源]