Mechanism of water pollution induced by some metal complexan and its management.

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Recently the eutrophication of the aquatic environment due to human activities has given rise to variety of problems of water pollution. Some kinds of water problems, such as mustry odor of drinking water, organic substances pollution in domestic area in Japan. This research was consisted of five subjects. (1)Distribution and fate of some kinds of complexans in river and lake water affecting domestic area : the changes of concentration of surfactants in river water was affected by the washing time in the 24 hours human activity cycle, and the concentration of surfactants was higher in winter seasons compared with that in summer seasons because of the bio-degradation by microorganism as well as NTA except for EDTA. (2)The effects of iron forms on the growth of four cyanobacteria were studied : Almost cyanobacteria was suppressed in the EDTA(complexing agent)-free CT medium because of no ability to utilize colloidal iron and iron oxides for its growth. (3)Microbial degradation of EDTA : The growth of organisms in the Fe^<3+>-EDTA medium were only slightly less than when cultured in the complete medium with Fe^<2+>-EDTA. Effect of another metals, Zn^<2+>, Mg^<2+>, Cu^<2+>, Ca^<2+>, Fe^<3+>, except for Fe^<2+> on the growth of psudomonus sp. was not recognized. It is suggested that efficiency of degradation increased with the repetitiveness of metal-complexan form for Fe^<2+>-EDTA <--> Fe^<3+>-EDTA, and also with glycine and IDA in the medium. (4)Effect of surfactants to the aquatic animals and plants. : the inhibition of metal toxicity and accumulation by the presence of surfactants was recognized for carp and water hyacinth. (5)Effect of complexans on the leaching metal from soil : the effect of EDTA for removing of heavy metals from metal-polluted soil was recognized. These results suggested that some kind of complexans are liable to cause water pollution problems in aqua-system.