六六六(HCHs)在小白洋淀水生植物中的分布与富集

利用GC-ECD测定了小白洋淀6个采样点的9种浮水、挺水和沉水植物中4种六六六(hexachlorocyclohexanes,HCHs)异构体的含量,分析了其分布、组成及富集特征。结果表明:1)小白洋淀水生植物中总HCHs含量范围在ND~7.47 ng·g-1(ww),浮水植物中HCHs含量最高,挺水植物各组织含量也有明显差异,根部HCHs含量明显高于茎叶2种组织。2)4种HCHs异构体中,γ-HCH的残留水平要显著高于其他3种异构体。在沉水植物和浮水植物中,均以γ-HCH占绝对比例,相对含量达60%~99%;而在挺水植物中,δ-HCHs占有较高比例,并且主要富集在挺水植物的根部,茎中次之,叶中最少。3)小白洋淀浮水植物和沉水植物HCHs含量与水体中HCHs含量呈显著的正相关关系,而挺水植物荷花、蒲草中HCHs各组分含量与水体中HCHs的相关关系不显著。4)水生植物对水中HCHs的富集系数BCF在8.7~661.2范围;浮水植物的BCF最高,沉水植物次之,挺水植物的茎对水体中HCHs的BCF最低。

Distributions and Bioconcentration of Hexachlorocyclohexanes (HCHs) in Macrophytes from Lake Small Baiyangdian

The contents of four hexachlorocyclohexanes (HCHs) isomers in the nine macrophytes species including floating,emergent and submerged ones from six sampling sites in Lake Small Baiyangdian were measured by GCECD.The distributions,compositions and bioconcentrations of HCHs were studied.The following results were obtained:1) the total wet-weight contents of HCHs range from ND to 7.47 ng· g-1(ww).The highest contents are found in floating plants.There are obvious differences in the HCHs contents in tissues of emergent plants.The highest contents are in the roots,followed by the leaves and stems.2) The residual level of γ-HCH is the highest among the four isomers of HCHs.γ-HCH is dominant with the percentage varying from 60％ to 99％ in the floating plants and submerged plants;however,the percentage of δ-HCHs is dominant in the roots of emergent plants,followed by the stems and leaves.3) There are significant positive correlations between the contents of HCHs in the floating and submerged plants and in water.4) The bioconcentration factors (BCFs) of HCHs in the macrophytes range from 8.7 to 661.2.The BCFs of HCHs are highest in the floating plants,followed by the submerged plants.The BCFs of HCHs in the stem of emergent plants are relatively low.