Question

What are the sources of marine pollution?

Answer 1

Marine pollution originates mainly from land‑based sources, including agricultural runoff carrying excess fertilizers and pesticides, untreated or poorly treated sewage and urban stormwater, industrial effluents, and river‑borne solid waste and plastics, which together deliver the majority of contaminants to coastal and open oceans. In addition, sea‑based activities such as shipping (operational discharges and garbage), offshore oil and gas operations, tanker and rig oil spills, dumping and dredging, and destructive fishing practices directly introduce oil, chemicals, and debris into marine environments. Atmospheric deposition of airborne pollutants and runoff from coastal and seabed mining also add toxic metals and nutrients, while thermal discharges from power plants and radioactive wastes from nuclear activities alter water temperature and introduce long‑lived contaminants; coastal development, tourism, and aquaculture contribute further localized pollution and habitat loss. These combined sources promote eutrophication and “dead zones,” cause wildlife mortality from oil and plastics, and lead to long‑term contamination of sediments and seafood.