ACCUMULATION AND DISTRIBUTION CHARACTERISTICS OF HEAVY METALS IN DIFFERENT SIZE MICROCYSTIS COLONIES FROM NATURAL WATERS

摘要

To investigate the accumulation and distribution characteristics of heavy metals in different size Microcystis colonies from natural waters, four size colonies (super-large colony, large colony, middle colony and small colony) were collected from Jin River during the high occurrence period of Microcystis blooms, and the sheaths were detached from intact undamaged algal cells via stirring with glass beads. Heavy metal (Pb, Cd, Cr, Al, Fe and Mn) accumulations, bioaccumulation in Microcystis cells and bioadsorption in sheaths were assayed using inductively coupled plasma-atomic emission spectrometry (ICP-AES), respectively. The results showed that heavy metal accumulations (except Cd) with significant differences in four size colonies, decreased in the following orders: middle colony, small colony, large colony and super-large colony. Accumulations of essential metals (Fe, Mn and Al) were much higher than nonessential metal (Pb, Cd and Cr) accumulations in colonies. The same changes in accumulation factor were observed in middle, large and super-large colonies. All measured heavy metal contents in algal cells, except Mn in super-large colonies and Cd in middle and super-large colonies, were higher than those in their sheaths at different degrees. Heavy metals in natural conditions might exert influence on colony formation via affecting EPS production and microsystins yield.