causes:
1. Industrial pollution: industrial wastewater, which contains many pollutants and complex compositions, is not only not easy to purify in water, but also difficult to treat. 2. Agricultural pollution: most of the pesticides and fertilizers remain in the soil and float in the atmosphere, and through rainfall, through the erosion of surface runoff, they enter the surface water and infiltrate into the surface water to form pollution. 3. Urban pollution: the mixture of various sewage produced in people's daily life, including the sewage discharged from kitchens, washing rooms, bathrooms and toilets.
Water pollution can come from a variety of sources. Pollution can enter water directly, through both legal and illegal discharges from factories, for example, or imperfect water treatment plants. Spills and leaks from oil pipelines or hydraulic fracturing (fracking) operations can degrade water supplies. Wind, storms, and littering—especially of plastic waste—can also send debris into waterways.
Thanks largely to decades of regulation and legal action against big polluters, the main cause of U.S. water quality problems is now "nonpoint source pollution," when pollutants are carried across or through the ground by rain or melted snow. Such runoff can contain fertilizers, pesticides, and herbicides from farms and homes; oil and toxic chemicals from roads and industry; sediment; bacteria from livestock; pet waste; and other pollutants.
Finally, drinking water pollution can happen via the pipes themselves if the water is not properly treated, as happened in the case of lead contamination in Flint, Michigan, and other towns. Another drinking water contaminant, arsenic, can come from naturally occurring deposits but also from industrial waste.
influences:
Water pollution can result in human health problems, poisoned wildlife, and long-term ecosystem damage. When agricultural and industrial runoff floods waterways with excess nutrients such as nitrogen and phosphorus, these nutrients often fuel algae blooms that then create dead zones, or low-oxygen areas where fish and other aquatic life can no longer thrive. Algae blooms can create health and economic effects for humans, causing rashes and other ailments, while eroding tourism revenue for popular lake destinations thanks to their unpleasant looks and odors. High levels of nitrates in water from nutrient pollution can also be particularly harmful to infants, interfering with their ability to deliver oxygen to tissues and potentially causing "blue baby syndrome." The United Nations Food and Agriculture Organization estimates that 38 percent of the European Union's water bodies are under pressure from agricultural pollution.  GGlobally, unsanitary water supplies also exact a health toll in the form of disease. At least 2 billion people drink water from sources contaminated by feces, according to the World Health Organization, and that water may transmit dangerous diseases such as cholera and typhoid.
resolutions:
In many countries, regulations have restricted industry and agricultural operations from pouring pollutants into lakes, streams, and rivers, while treatment plants make our drinking water safe to consume. Researchers are working on a variety of other ways to prevent and clean up pollution. National Geographic grantee Africa Flores, for example, has created an artificial intelligence algorithm to better predict when algae blooms will happen. A number of scientists are looking at ways to reduce and cleanup plastic pollution.
Anyone can help protect watersheds by disposing of motor oil, paints, and other toxic products properly, keeping them off pavement and out of the drain. Be careful about what you flush or pour down the sink, as it may find its way into the water. The U.S. Environmental Protection Agency recommends using phosphate-free detergents and washing your car at a commercial car wash, which is required to properly dispose of wastewater. Green roofs and rain gardens can be another way for people in built environments to help restore some of the natural filtering that forests and plants usually provide.