Sewage discharge, which includes untreated or partially treated wastewater, is a major contributor to water pollution in urban areas, as it introduces harmful bacteria, nutrients, and other contaminants into water bodies.

Fertilizer application, particularly the excessive use of nitrogen and phosphorus-based fertilizers, can lead to nutrient pollution in water bodies, causing eutrophication and harmful algal blooms.

Eutrophication is the process by which excess nutrients, primarily nitrogen and phosphorus, stimulate excessive growth of algae and other aquatic plants, leading to oxygen depletion and disruption of aquatic ecosystems.

Arsenic is a highly toxic water pollutant that can cause various health issues, including cancer, reproductive problems, and neurological disorders. It can enter water sources through natural processes or human activities such as mining and industrial discharge.

Ocean acidification is primarily caused by the increased absorption of carbon dioxide from the atmosphere into the ocean. This leads to a decrease in the pH of seawater, making it more acidic and harmful to marine life.

Bioremediation is a water treatment process that utilizes microorganisms, such as bacteria and fungi, to break down and remove contaminants from water. This process is often used to clean up contaminated groundwater and soil.

Biomagnification is the process by which toxic substances, such as heavy metals and pesticides, accumulate in the tissues of organisms as they move up the food chain. This can lead to high concentrations of these substances in top predators, posing a risk to their health and the health of humans who consume them.

The MARPOL Convention (International Convention for the Prevention of Pollution from Ships) is an international agreement that aims to reduce pollution from ships, including oil spills, sewage discharge, and air pollution.

Salinization is the process by which water becomes contaminated with salt. This can occur naturally through the weathering of rocks or through human activities such as irrigation and mining.

Pesticides, particularly those containing certain chemicals like atrazine and simazine, can be harmful to coral reefs. These chemicals can disrupt the symbiotic relationship between corals and algae, leading to coral bleaching and death.

Heavy metal contamination is the process by which water becomes contaminated with heavy metals, such as lead, mercury, and cadmium. This can occur through natural processes or through human activities such as mining and industrial discharge.

Reverse osmosis is a water treatment process that utilizes a semipermeable membrane to remove impurities, including salts, minerals, and contaminants, from water.

Acidification is the process by which water becomes contaminated with acids. This can occur naturally through the weathering of rocks or through human activities such as acid rain and industrial discharge.

Mercury is a highly toxic water pollutant that can cause various health issues in aquatic life, including respiratory problems, gill damage, and neurological disorders. It can enter water sources through natural processes or through human activities such as mining and industrial discharge.