小微企业镀锌废水排放污染与环境风险分析

Analysis on discharge pollution and Environmental risk of Zinc plating Wastewater in small and Micro Enterprises

以安徽省某市五个镀锌加工厂为研究对象,应用单项污染指数法、地积累指数法和潜在生态风险指数法对其排放废水中TZn浓度及其排污沿线土壤中TCr、TZn浓度的检测结果进行了超标分析,评价了TCr、TZn的污染强度及其造成的土壤环境质量改变和生态风险。结果显示:(1)五个厂排污沿线附近土壤TCr、TZn浓度均呈现不同程度的超标积累,有部分Cr和Zn发生了迁移;(2)五个厂TCr中强度～极严重污染导致土壤环境质量呈重度污染,五个厂TZn强～极严重污染导致土壤环境质量呈重度污染,其它强度下土壤境质量改变很小;(3)厂1的厂外排污口附近土壤Cr和Zn的单因子生态风险较重,总的潜在生态风险呈中度,厂3河床边底泥Cr具有中度生态风险,其它区段单因子生态风险和总的潜在生态风险均较低。研究表明,镀锌企业废水不经处理排放会造成土壤环境质量发生一定改变,并具有一定的生态风险。

Taking five zinc plating plants in a certain city of Anhui Province as the research object,the methods of the single pollution index,geoaccumulation index and potential ecological risk index were applied on analyzingthe TZn concentration in wastewater and that of TCr,TZn in soil along the discharge lines,and evaluating the pollution intensity of TCr,TZn,changes of soil environmental quality and ecological risks caused by TCr,TZn.The results showed that,(1)The concentrations of TCr,TZn in the soil near the sewage discharge line of the five plants all showed different degrees of over-standard accumulation,and some migrated.(2)The TCr pollution from intensity to extremely serious from five factories resulted in serious pollution of the soil environmental quality,and so did The TZn pollution from strong to extremely serious,however,the change of the soil environmental quality was very small under other intensities.(3)The single factor ecological risk of Cr and Zn in the soil near the outlet of plant 1was heavy,meanwhile,the total potential ecological risk was moderate,the sediment in the riverbed side of plant 3 had a moderate ecological risk,and the single factor and total ecological risk in the other sections were lower.The research indicated that the soil environmental quality will be changed and the ecological risks will be caused by the untreated waste water discharged from zinc plating plants.