Final answer:
The Cuyahoga River in Cleveland caught fire multiple times due to pollution, which prompted the United States to prioritize cleaner water. Water pollution is a result of industrialization, population growth, and urbanization. Pollution from various sources can contaminate the water supply and impact aquatic life and human health.
Step-by-step explanation:
Water pollution has always been a byproduct of industrialization, increased population, and urbanization. Cleveland's Cuyahoga River caught fire several times due to pollution, and was part of what inspired the United States' turn to cleaner water. Other countries are currently undergoing the same crises. As a consequence of population concentrations, water close to human settlements is frequently polluted with untreated or partially treated human waste (sewage), chemicals, radioactivity, and levels of heat sufficient to create large "dead zones" incapable of supporting aquatic life.
The methods of food production used by many core nations rely on liberal doses of nitrogen and pesticides, which end up back in the water supply. In some cases, water pollution affects the quality of the aquatic life consumed by water and land animals. As we move along the food chain, the pollutants travel from prey to predator. Since humans consume at all levels of the food chain, we ultimately consume the carcinogens, such as mercury, accumulated through several branches of the food web.