水污染(water pollution)
在海洋、湖泊、河川及溪流中积集的物理、化学和生物物质，它直接对人的生命造成危害，或间接地具有危险的长期效应。主要来源包括下水道的废物、工业废物、废料、垃圾和农业肥料、杀虫剂、除草剂，另外一个严重问题是油船碰撞或油船漏泄造成的海洋污染。工业化和都市化是造成今日水污染继续恶化的原因。某些工业有机废料和家庭废料是微生物分解性废料，即如果充分供给氧则会自然地被微生物分解。不可分解的工业废料包括盐类和其他化学品，这些物质进入水中，会提高流动水的酸度或硷度，常达到生物不能生存的程度。水中的悬浮微粒，既有害又能促使细菌繁殖。除污水处理系统外，水污染控制技术还包括工业废水，特别是造纸厂和食品加工厂这种大污染源的处理。同时，对农业杀虫剂、除草剂、肥料和动物废料制订了不少控制措施。
English version：
water pollution
State resulting when substances are released into a body of water, where they become dissolved or suspended in the water or deposited on the bottom, accumulating to the extent that they overwhelm its capacity to absorb, break down, or recycle them, and thus interfering with the functioning of aquatic ecosystems. Contributions to water pollution include substances drawn from the air (see acid rain), silt from soil erosion, chemical fertilizers and pesticides, runoff from septic tanks, outflow from livestock feedlots, chemical wastes (some toxic) from industries, and sewage and other urban wastes from cities and towns. A community far upstream in a watershed may thus receive relatively clean water, whereas one farther downstream receives a partly diluted mixture of urban, industrial, and rural wastes. When organic matter exceeds the capacity of microorganisms in the water to break it down and recycle it, the excess of nutrients in such matter encourages algal water blooms. When these algae die, their remains add further to the organic wastes already in the water, and eventually the water becomes deficient in oxygen. Organisms that do not require oxygen then attack the organic wastes, releasing gases such as methane and hydrogen sulfide, which are harmful to the oxygen-requiring forms of life. The result is a foul-smelling, waste-filled body of water. See also eutrophication.