福建省东山湾生态环境中滴滴涕(DDTs)的分布特征及风险评价

Distribution characteristics and risk assessment of Dichloro-diphenyl-tricgloroethanes in Dongshan Bay, China

根据2011年春季(5月)和夏季(8月)对东山湾生态环境的调查资料,初步探讨了东山湾海水、沉积物和养殖贝类体中滴滴涕(DDTs)残留水平、分布趋势和组成特征,并对东山湾生态环境中DDTs污染状况及其生态风险进行了评价。结果表明:(1)春季(5月)和夏季(8月)东山湾表层海水中DDTs质量浓度范围分别为ND^25.7 ng/L和ND^36.7 ng/L,平均值分别为(6.08±3.02)ng/L和(16.30±4.78)ng/L;底层海水中DDTs质量浓度范围分别为ND^30.6 ng/L和ND^36.7ng/L,平均值分别为(7.75±2.07)ng/L和(13.30±5.12)ng/L,总体上,东山湾海水中DDTs浓度分布呈夏季高于春季、近岸高于远岸、由湾内向湾外下降的格局。与国内其他海湾相比,东山湾海水中DDTs污染处于低水平状态,但邻近漳江入海口海域的DS03站和DS11站可能有新的污染源输入。(2)东山湾表层沉积物中DDTs含量范围5.56~12.80μg/kg,平均值为(9.00±5.34)μg/kg,总体上呈现由湾内向湾外下降之势,东山湾表层沉积物中DDTs残留可能对生物产生负效应,毒性风险为25%~75%。(3)东山湾海域养殖贝类DDTs的残留量在种类间存在一定的差异,其DDTs含量范围在1.68~26.60μg/kg,平均值为15.70μg/kg,污染指数范围在0.007~2.660,均值为1.580,超标率达到71.4%,超标倍数最高达1.66倍,说明东山湾部分贝类受到DDTs的污染。

An investigation into the residue, distribution, and composition of Dichloro-diphenyl-tricgloroethanes （DDTs） in sea water, sediment, and cultured shellfish in Dongshan Bay was carried out in spring（May） and summer（August）, 2011. We also evaluated the contamination status and ecological risks. The results were as follows： First, the DDT content in the sea surface layer varied from non-detectable（ND） to 25.7 ng/L in May and from ND to 36.7 ng/L in August, the average values were （6.08±3.02） ng/L and （16.30±4.78） ng/L, respectively; the DDT content in the bottom layer varied from ND to 30.6 ng/L and from ND to 36.7 ng/L, the average values were （7.75±2.07） ng/L and （13.30±5.12） ng/L in May and August, respectively. In general, the DDT concentration distribution in Dongshan Bay declined from the inner to outer bay and from the near- to far-shore. DDT concentrations in summer were higher than those in spring. Compared with other bays in China, DDTs pollution in Dongshan Bay was at a lower level status; however, it is likely that there has been a recent pollutant input in sites DS03 and DS11. Second, the DDT content in the sediment varied from 5.56？12.8 μg/kg, the average value was （9.00±5.34） μg/kg. The concentration declined from the inner to the outer bay. DDT residue in the sediment may have negative effects on organisms, the toxicity risk index varied from 25% to 75%. Third, the DDT content varied among different species of cultured shellfish from 1.68？26.60 μg/kg and the average was 15.70 μg/kg. The pollution index varied from 0.007 to 2.660, the average was 1.580. This exceeded the standard rate by 71.4% and the highest value was 1.66 fold. These results show that some shellfish have been contaminated by DDTs. This problem requires further attention and must be resolved.