4.2.2 Liver Cancer and Drinking Water

4.2.2 Liver Cancer and Drinking Water

Epidemiological surveys show a close relationship between liver cancer and drinking water. Residents who drink polluted pond water have a liver cancer incidence of 60–101 per 100,000, whereas residents who drink well water have an incidence of 0–19 per 100,000. Due to the large amount of pollutants discharged into pond water, algae, especially blue-green algae, proliferate extensively, producing microcystin toxins that can promote mutations in exon 8 of the P53 gene, eliminating its ability to positively regulate apoptosis and leading to uncontrolled liver cell proliferation [76–78]. Microcystin toxins can also inhibit the dephosphorylation activity of protein phosphatases, causing phosphorylated proteins to accumulate and unable to suppress cell proliferation. Although the concentrations of hexachlorocyclohexane, organochlorine compounds, and DDT in various types of drinking water are very low, long-term intake of these carcinogens gradually accumulates and can still reach carcinogenic thresholds [79], ultimately leading to cancer.