白洋淀水生食物链BHC、DDT生物浓缩分析

A Study on Bioaccumulation and Biomagnification of BHC and DDT in Baiyangdian Lake Foodweb .

为了评价ＢＨＣ和ＤＤＴ在水生食物链的生物累积放大效应，对白洋淀地区端村水域生态系统水、泥及水生生物体内六六六、ＤＤＴ含量进行分析．结果表明，白洋淀水域生态系统水生生物对六六六、ＤＤＴ的富集沿食物链生物营养等级而递增的规律性较强（当年生鲫鱼例外）．水体、底泥、水生维管束植物、浮游动物、底栖动物、当年生鲫鱼及２龄乌鳢体内六六六残留量分别为：０．３μｇ／Ｌ、０．７μｇ／ｋｇ、１９．０μｇ／ｋｇ、３０．０μｇ／ｋｇ、６０．９μｇ／ｋｇ、１７．２μｇ／ｋｇ、１１０．７μｇ／ｋｇ、；ＤＤＴ残留量分别为：０．１μｇ／Ｌ、０．７μｇ／ｋｇ、６．３μｇ／ｋｇ、２１．０μｇ／ｋｇ、３７．９μｇ／ｋｇ、１９．４μｇ／ｋｇ、１２４．４μｇ／ｋｇ．水生生物对ＤＤＴ的富集系数（６３—１２４４）明显超过六六六（６３．３—３６９）．水生生物体内六六六４种异构体的含量顺序（α＞δ＞γ＞β）与其在水体及底泥中的含量顺序（α＞γ＞δ＞β）略有不同．在白洋淀水生生态系统中ＤＤＴ主要以代谢物Ｐ，Ｐ＇－ＤＤＥ形式存在，但少量的ＤＤＴ最初化合物Ｐ，Ｐ＇－ＤＤＴ的检出，说明白洋淀水环境最近受到ＤＤＴ的轻度污染．

BHC、DDT and their metabolites were analysed in Duancun area from Baiyangdian Lake ecosystem in June 1995.The content levels of pesticides in water and bottom sediments were relatively lower:in water,the average values of BHC and DDT were 0.3μg/L and 0 1μg/L,respectively;in sediments,the residue level of BHC was same with DDT with a mean concentration of 0.7μg/kg(wet).The organochlorine insecticides content in aquatic organisms was much higher:the average concentration of BHC in hydrophytes,planktons,benthic macroinvertebrates,young of the year Carassius auratus and 2 year old Ophiocephalus crispus was 19 0,30 0,60 9,17 2 and 110 7 μg/kg,respectively;for DDT, the content sequence was 6.3,21.0,37.9,19.4 and 124.4g/kg,respectively.So the lipophilic nature and low biodegradation rates of BHC and DDT led to the accumulation of these compounds and subsequent magnification of concentration in organisms progressing up the food chain.DDT had a much profound bioaccumulation potential than BHC for the bioconcentration factor of DDT in organisms(63.3-1244) was well above that of BHC (63-369).The ratios of BHC isomers monitored in organisms(δ>α>γ>β)were different from that in water and sediments(α>δ>γ>β).The predominant DDT derivative was p,p' DDE.Base upon the observed that the original DDT (P,P' DDT)was indentified in some specimens,it has been concluded that there was a recent input of DDT to Baiyangdian Lake.