【摘要】 于2013-2014年间对湖州市5个县(区)98个养殖池塘及其周边外河采集表层沉积物,原子吸收法测定Cu、Zn、Pb、Cd、Cr干重,原子荧光法测定Hg、As干重。结果表明:养殖池塘表层沉积物中相对土壤背景值Cd、Zn污染程度较高,绝对浓度分别为0.24 mg/kg和105.82 mg/kg,As较为清洁;县(区)间养殖池塘表层沉积物Hakanson潜在生态风险均为中等污染水平,远低于周边外河,但高于本地区耕地等土壤的污染水平,说明渔业生产过程中存在输入性污染;单个重金属生态风险系数中Cd为强、Hg为中等,依次为Cu、Pb、As、Cr、Zn,均为轻微生态风险水平。此外,池塘表层沉积物中Cu、Zn、Cr两两之间显著相关,符合这三种重金属在水产饲料中同时添加的特性;而Cd与Cu、Zn显著相关,一定程度上印证了Cd在水产饲料中可能超标的事实,但其生态风险系数远低于周边外河表层沉积物,所以周边流域外源性Cd输入风险也需要关注。更多还原

【Abstract】 During the period of 2013 to 2014,sediment samples from aquaculture ponds and their nearby rivers were collected from 5 counties( or districts) in Huzhou City. The contents of Cu,Zn,Pb,Cd,Cr in all the samples were determined by using an atomic absorption spectrophotometer and the contents of Hg and As were analyzed by using an atomic fluorescence spectrophotometer with the recommended instrument parameters. Results showed that the contents of Cd and Zn in collected samples were higher than those in the background soils,with the concentrations of 0. 24 mg / kg and 105. 82 mg / kg in dry weight,respectively; while the concentration of As was at a clear level. The middle level of Hakanson potential risks from 5 counties was much lower than the level of sediments from nearby rivers but higher than that from the cultivated lands in Huzhou district,implying that activities of aquaculture production may lead to heavy metal pollution. Results of Hakanson potential ecological risk assessment showed that the decreasing values of the hazard risk indices were Cd,Hg,Cu,Pb,As,Cr,Zn in sequence,among which Cd and Hg were in strong and middle level of risk,respectively,others were at a slight level. The significant linear relationships among Cu,Zn and Cr implied that they probably had the same sources from fish feeds. Besides, the significant relationships between Cd, Cu and Zn indicated Cd might exists in fish feeds. Meanwhile,the potential ecological risk of Cd in aquaculture ponds was much lower than those in nearby rivers. Hence,more attentions should be paid to the exotic sources of Cd pollution.更多还原