汞在腐殖酸影响下对浮游植物的毒性及其富集的研究

本实验研究受汞严重污染的蓟运河水体中,腐殖酸对汞抑制浮游植物生长及光合作用的影响、对汞富集的影响及不同组分腐殖酸影响的差异。实验证明,腐殖酸能降低汞对莱因衣藻(Chlamydomonas reinhardi)、斜生栅藻(Scenedesmus obliquus)及布朗纤维藻(Ankistrodesmus braunii)生长的抑制。黄腐酸(FA)、棕腐酸(HA)及其混合液(FA/HA)的作用无显著差异。但在高汞浓度下(1ppm),HA及FA/HA的效果大于FA;FA及HA可降低汞对斜生栅藻光合作用的抑制,并能使光合较早得到恢复、腐殖酸能减少斜生栅藻对汞的富集。

EFFECT OF HUMIC SUBSTANCES ON TOXICITYAND ACCUMULATION OF MERCURYIN PHYTOPLANKTON

Humic substances extracted from sediment of Jiyun River in north of China helps reduce inhibiting effect of Hg on growth of Scenedesmus obliquus, Chlamydomonas reinhardi and Ankistrodesmus braunii. Degree of reduction was related to sensitivity of the species to Hg. Fulvic acid (FA),humic acid (HA) and their mixture (FA/HA) showed no significant difference in effect, but at high Hg concentration (1ppm), HA and FA/HA were found to be more effective than FA.FA and HA reduced inhibitory effect of Hg on photosynthesis in S. obliquus, and caused more rapid recovery than the control.Humic substances induced a decrease in Hg accumulation by S. obliquus, which, in turn, was due to a reduction in Hg absorbed into the cell and firmly bound on the cell membrane, while the amount of Hg loosely adsorbed on the cell surface remained unchanged. Effect of FA, HA and FA/HA on Hg accumulation was found to have no significant difference,but the firmly adsorbed Hg in FA treatment was higher than those in HA and FA/HA.