More than 3 million metric tons of oil contaminates the sea every year. The majority of oil pollution in the oceans comes from land. Runoff and waste from cities, industry, and rivers carries oil into the ocean. Ships cause about a third of the oil pollution in the oceans when they wash out their tanks or dump their bilge water. Spilled oil poses serious threats to fresh water and marine environments, affecting surface resources and a wide range of subsurface organisms that are linked in a complex food chain that includes human food resources. Spilled oil can harm the environment in several ways, including the physical damages that directly impact wildlife and their habitats (such as coating birds or mammals with a layer of oil), and the toxicity of the oil itself, which can poison exposed organisms. The severity of an oil spill’s impact depends on a variety of factors, including the physical properties of the oil, whether petroleum-based oils or non petroleum-based oils, and the natural actions of the receiving waters on the oil. Aquatic flora and fauna results mainly due to occlusion of light from the water, reduction of oxygen transfer from air to water, toxicity of some of the oil fractions to certain aquatic species, suffocation of fish due to coating of gill filaments and destruction of some species of algae, plankton and bottom dwelling organisms due to coating of oil film.
No comments:
Post a Comment