天津地区鱼塘水、悬浮物、沉积物和鱼体中的DDT

DDT and its metabolites in water,suspended solid,sediment and fish in fishponds in Tianjin

  • 摘要: 采样测定了天津地区2典型鱼塘鲫鱼、鲢鱼、水、悬浮物、沉积物和鱼塘周边表土中的DDT及其代谢产物含量。结果发现,2鱼塘各主要介质以及鱼体肌肉和器官中都富集了较高浓度的DDT。鲫鱼和鲢鱼肌肉中DDT的含量分别为(66.4±2.7)ng·g-1和(24.3±23.4)ng·g-1。肝胰脏、肠和鱼鳃中DDT含量一般高于肌肉,其中肠的富集量最大,是肌肉的3倍以上。生物富集系数(lgBCF)分别为3.7和3.3。2鱼塘鱼体和各相含量有较大差别,鱼塘介质中悬浮物富集浓度最高。表土污染相对严重地区的鱼塘中各介质和鱼体DDT含量均高于另一污染较轻的鱼塘。污染严重鱼塘的DDE/ΣDDT含量比值也相对较高,反映早期污染残留的重要特征。尽管如此,仍然较高的DDT含量以及悬浮物中很低的DDE/ΣDDT含量比值说明很可能还有污染源存在。

     

    Abstract: DDT and its metabolites(DDT residues)were measured in water,suspended solid(SS),sediment and fish(Carassius auratus and Hypophthalmichthys molitrix)from two fishponds as well as top soils on their shores in Tianjin.It was found that all the media(including fish muscle and organs)were severely contaminated with DDT residues. The mean concentration of DDT residues in fish muscle was (66.4±2.7)ng·g-1 for Carassius auratus and (24.3±23.4)ng·g-1 for Hypophthalmichthys molitrix,respectively.The ΣDDT concentration in intestines was 3.2-3.9 times higher than in fish muscle. However,the ΣDDT content in gills was only 1.3-1.7 times higher than the content of DDT residues in fish muscle,indicating that DDT residues may accumulate in fish via intake of suspended particles(ingestion process)as well as via direct intake from water by gills.Their bioconcentration coefficient(lgBCF)reached 3.7 and 3.3,respectively.The two fishponds differed significantly in DDT residue content.ΣDDT concentrations in various media were much higher in the fishponds located in the area with the top soil severely contaminated with DDT residues than the other in the area less contaminated. The ratios of DDE/ΣDDT were relatively high for that severely contaminated fishpond,indicating heavy application of DDT in the past.However,the very low DDE/ΣDDT values in suspended solids along with the relatively high DDT concentrations suggested recent inputs of DDT.

     

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