畜禽养殖污染对土壤和地下水的影响——以北京市顺义区龙湾屯镇为例

Effect of Livestock and Poultry Pollution on Soil and Groundwater—A Case Study of Longwantun Town,Shunyi District,Beijing

为查明畜禽养殖业对北京市顺义区龙湾屯镇生态环境造成的影响,对龙湾屯镇畜禽养殖污染开展了深入研究。结果表明,除猪场样点3中的Cu和Zn含量高于农用地土壤污染风险筛选值外,畜禽养殖区外围其他样点中的Cd、Hg、As、Cu、Zn、Ni含量均低于农用地土壤污染风险筛选值;与北京市土壤背景值相比,畜禽养殖区外围土壤中的Hg、As、Cu、Zn、Ni这5种重金属元素均有不同程度超标,说明有外源物质进入,外源物质主要为畜禽养殖区的动物粪便;单因子污染指数评价结果显示,除猪场样点3的Cu、Zn污染指数在1~2,为Ⅱ级轻度污染外,畜禽养殖区外围其他样点的单因子污染指数均小于1,为Ⅰ级无污染;内梅罗综合污染指数(PN)评价结果显示,除猪场样点3的PN在1~2,为Ⅲ级轻度污染外,畜禽养殖区外围其他样点的PN均小于0.7,为Ⅰ级清洁(安全);潜在生态危害指数法评价结果表明,Hg为龙湾屯镇畜禽养殖区外围土壤重金属的主要生态危害因子,应将其作为优先控制的污染元素;龙湾屯镇畜禽养殖区外围地下水不符合《生活饮用水卫生标准》,总大肠菌群、菌落总数和硝酸盐均有一定程度超标,造成其超标的主要原因可能是未经过处理的养殖废水随地表水进入地下水;由于施过动物粪便的土壤中存在一定的粪大肠菌群,这些粪大肠菌群会通过土壤渗滤途径进入地下水,最终对井水产生影响。

In order to find out the influence of livestock and poultry farming on the ecological environment of Longwantun Town,we carried out an in-depth study on the pollution of livestock and poultry breeding in Longwantun Town.The results showed that the content of Cu and Zn in pig plot 3 was higher than that in agricultural soil pollution risk screening value,and the Cd,Hg,As,Cu,Zn,Ni content in other sampling sites around livestock and poultry breeding area was lower than that in agricultural land soil pollution risk screening value.Compared with the background value of soil in Beijing,the five heavy metal elements of Hg,As,Cu,Zn,Ni in the soil around the livestock and poultry breeding areas exceeded the standard in varying degrees,indicating that there were foreign substances entering,and the exogenous substances were mainly animal feces in the livestock and poultry breeding areas.The results of single factor pollution index evaluation showed that except the Cu,Zn pollution index of pig farm sample point 3 was between 1 and 2,which was gradeⅡslight pollution,the single factor pollution index of other samples around livestock and poultry breeding area was less than 1,which showed that there was no pollution of gradeⅠ.The results of Nemero comprehensive pollution index evaluation(PN)showed that except the PN of pig farm sample point 3 was between 1 and 2,which was gradeⅢslight pollution,the PN of other sampling sites around livestock and poultry breeding area was less than 0.7,which was gradeⅠclean(safe).The evaluation results of potential ecological hazard index showed that Hg was the main ecological hazard factor of heavy metals in the surrounding soil of Livestock and Poultry breeding area in Longwantun Town,and it should be regarded as the pollution element of priority control.The groundwater outside the livestock and poultry breeding area in Longwantun Town did not meet the Sanitation Standard of Drinking Water,and the total coliform,total colony and nitrate exceeded the standard to a certain extent.The main reasons for exceeding the standard may be the untreated aquaculture wastewater enters into groundwater with the surface water;due to the presence of fecal coliform in the soil where animal excrement has been applied,there is a certain number of fecal coliform bacteria in the soil.These fecal coliform groups will enter into groundwater through soil percolation,which will eventually affect well water.In allusion to the pollution problem of livestock and poultry breeding in Longwantun Town,the corresponding prevention and control countermeasures were put forward.