Study on the relationship between pollution of alga and microcystins in source water and digestive system cancers

[Objective]To assess the eutrophication of source water and discuss the relationship between the pollution of alga and micro-cystins and digestive system cancers. [Methods]The data from the typical surveillance and the published research papers are checked up and re-analyzed. The drinking water's physical and chemical index were sampled and determined according to GB5750. The sampling and determination of alga and chlorophyll were conducted according to "regulation for investigation on eutrophication of lakes". Microcystins were determined with ELISA method. [Results) Categories of algae were mainly cyanophyta, cryptophyta, euglenophyta, chlorophyta. According to the grade of eutrophication, the ranking of waters are Luoma lake, Beishan Water-reservoir, river freshwater in Rudong and Canal, and Yangtse river from more eutrophic to less eutrophic. The descending ranking of microcystins positive rate was ditch-pool water; river water, shallow-well water, and deep-well water. Additionally, the microcystins positive rate of deep-well water was zero. The water supplied by the water plants whose source water was from Tai lake contained microcystins. The highest death rate of liver cancer was found in the habitants who drank and used the house ditch water, followed by pool water, river water, and shallow-well water. Popular regions of alimentary canal tumors were mainly ones where the source water was eutrophicated and had comparatively high mycrocystins. [Conclusion]The pollution of alga and alga toxins became the important factor which universally aggravated source water. The eutrophication and pollution of alga and microcystins could do harm to human's health. Much evidence has showed a close relationship between alga, microcystins and high popularity of tumors.