珠江三角洲养殖鱼塘水体中重金属污染特征和评估

为了解珠江三角洲主要养殖环境中重金属含量及潜在生态危害程度，用电感藕合等离子质谱法和原子荧光法测定了肇庆、广州、惠州和茂名4市14个样点沉积物中7种元素的水体及底泥总量，并对底泥中主要重金属污染状况及潜在生态风险进行了评价。结果表明：养殖鱼塘水体中Cr质量浓度范围是nd-0.1011 mg·L-1，超标率为7.1%，Cu质量浓度范围为nd-0.1438 mg·L-1，超标率为64.3%，As质量浓度范围是0.0112-0.0812 mg·L-1，超标率为24.1%，Hg质量浓度范围是0.00004-0.00458 mg·L^-1，超标率为35.7%，Pb质量浓度范围为nd-0.0973 mg·L^-1，超标率为6.8%，其余Ni、Zn和Cd质量浓度范围分别为nd-0.0218、nd-0.0232和nd-0.00319 mg·L^-1，均未超渔业水质标准；底泥中重金属元素Cr、Cu、Zn、As、Hg、Cd和Pb的平均值分别为83.86、46.19、242.16、32.38、0.64、1.00和60.06 mg·kg^-1，地积累指数评价结果显示，表层沉积物重金属污染程度顺序为Cd＞Hg＞Zn＞Pb＞As＞Cu＞Cr，其中，Cd污染程度为中-强，是底泥污染最严重的元素。潜在生态风险指数分析，单项潜在生态风险指数生态风险均值排列顺序为 Hg＞As＞Cd＞Pb＞Cu＞Zn＞Cr。对区域综合潜在生态风险指数RI的贡献率最大的元素为Hg、As和Cd。4个市底泥潜在生态风险综合指数（RI）比较，惠州（290.13）＞广州（240.54）＞茂名（193.23）＞肇庆（116.40）。Hg和Cd是该水域污染和潜在生态风险最大的元素。

Residues and potential ecological risk assessment of metal in water and sediments from freshwater fish pond of Pearl River Delta

In order to investigated the metals concentrations and their potential ecological risks of heavy metals in water and surface sediments from freshwater fish pond of Pearl River Delta, 14 sampling sites were collected from four cities such as Guangzhou, Zhaoqing, Huizhou and Maoming. Total contents of Cr,Ni, Cu, Zn, As, Hg, Cd and Pb in these samples were measured by （ICP-MS） and Atomic Fluroresence spectrometry （AFS） and using the Index of Geoaccumulation and the Potential Ecological Risk Index evaluate the pollution degree of many heavy metals in the sediments. Results indicated that the exceed standard rates of Cr, Cu, As Hg and Pb in water were 7.1%, 64.3%, 24.1%, 35.7% and 6.8% respectively and Ni, Zn, Cd were not exceed the standard of fishery water quality of china, the average concentration of Cr, Cu, Zn, As, Hg, Cd and Pb in sediments of fish pond were 83.86, 46.19, 242.16, 32.38, 0.64, 1.00 and 60.06 mg·kg^-1respectively. The descending order of pollution degree of various metals is： Cd 〉Hg〉Zn 〉Pb 〉As〉 Cu〉Cr,while the single potential ecological risk followed the order： Hg〉As〉Cd〉Pb〉Cu〉 Zn 〉Cr, comparing with potential ecological risk index of four cities ranked in the order of Huizhou （290.13）, Guangzhou（240.54）, Maoming（193.23） and Zhaoqing（116.40）, The pollution extent and potential ecological risk of Cd and Hg were the most serious among all heavy metals.