水是疾病传播的重要媒介。水污染对人体的危害是多方面的，当人体受到化学有毒物质污染后，会引起人的急性或慢性中毒。如果汞、镉、砷、氰化物、农药、多氯联苯等侵入人体后，都可以引起人体中毒。污水中有害物质在土壤中积累并被植物吸收，加上不适当地使用化学农药，会使大量残留的有害物质散布到田间，继而污染粮食、蔬菜、烟叶等农副产品，引起疾病。另外，水污染还会引起水媒介的传染病，如人畜粪便等生物性污染，可以引起细菌性肠道传染病，如伤寒、痢疾、霍乱等。Water is an important medium for the spread of the disease.The harm of water pollution on the human body are many,when the human body by the toxic chemical pollution,cause acute or chronic poisoning people. If mercury,cadmium, arsenic, cyanide, pesticides, polychlorinated biphenyls, invades the human body, can cause human body poisoning. Sewage harmful substances accumulate in the soil and uptake by plants, and inappropriate use ofchemical pesticides, will make large amounts of harmful substances residue spread into the field, then the pollution of food, vegetables, tobacco and other agricultural and sideline products, cause disease. In addition, the water pollution will cause water media of infectious diseases,such as human and animal feces and other biological pollution, can cause bacterial intestinal infectious diseases,such as typhoid, dysentery, cholera.希望可以帮到你，祝你学习进步，更上一层楼!~~让我们共同努力吧！加油
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