秋茄对镉-甲胺磷混合物的吸收积累及致毒作用

Removal and toxicity of pollutant Cadmium by Kandelia candel in the presence of Methamidophos

本文采用砂培实验,测定了红树植物秋茄幼苗对镉和镉-甲胺磷的吸收积累和净化作用,探讨了镉-甲胺磷混合物对秋茄的毒性作用。实验结果表明:虽然100 mg·L^(-1)甲胺磷并不影响秋茄对镉的净化作用,但100 mg·L^(-1)甲胺磷的存在却加强了镉对秋茄的毒性作用。这可能是由于镉对秋茄幼苗的膜脂过氧化作用,改变秋茄幼苗细胞膜的通透性和流动性,使甲胺磷易于从水体向秋茄幼苗的转移,从而加强了镉对秋茄的毒性效应。因此,在确定红树植物对镉“耐受临界浓度”时,建议考虑其它化合物与镉对红树植物的联合毒性作用。

Based on the pot experiments in sand culture, both the removal of pollutant Cadmium by Kandelia candel and the toxicity of Cadmium to seedlings Kandelia candel were determined in the absence and presence of Methamidophos, respectively. The results showed that, although 100 mg·L^(-1) Methamidophos had no effect on the removal of pollutant Cadmium by soil-culture Kandelia candel, there was a synergistic toxicity effect between Cadmium and 100 mg·L^(-1) Methamidophos to seedlings Kandelia cande. It assumed that this synergistic toxicity effect might result from the membrane-lipid pemxidation of Cadmium vs. seedlings Kandelia candel: this peroxication would no doubt enhance the ability of Kandelia candel to be penetrated, then facilitate the transfer of Methamidophos from water into Kandelia candel, thus lead to the synergistic toxicity between Cadmium and Methamidophos. Therefore, it is suggested that the mixture toxicity between Cadmium and other pollutants should be considered to determine the tolerance concentration of Cadmium to Kandelia candel.