Impacts of pollution on coastal and marine ecosystems including coastal and marine fisheries and approach for management: a review and synthesis
- Only 'one pollution' because every pollutant, whether in the air, or on land tends to end up in the ocean.
Major pollutants-
1. fertilizers, pesticides, and agrochemicals
§ Agricultural activities are reported to contribute about 50% of the total pollution source of surface water by means of the higher nutrient enrichment
§ Bioaccumulation and biomagnifications
2. Domestic and municipal wastes and sewage sludge
§ greatest volume of waste discharged to the marine environment is sewage
§ can lead to eutrophication- high BOD
3. Oils
§ half a million tons of persistent oils are discharged into the sea each year
§ There are enough evidences that oil pollution poses serious adverse effects on aquatic ecosystem and the organisms extending from primary producers level through secondary, tertiary and up to the top levels.
§ The sensitivity of echinoderms and mollusks can be understood from the use of oil slurries to form a barrier around oyster beds to protect them from predatory mollusks and sea-stars
4. Heavy metals and trace elements
§ they bioaccumulate in marine organisms and concentrate year after year
§ Heavy metals interference are reported to cause an increase in the permeability of the cell membrane in phytoplankton and other marine algae, leading to the loss of intracellular constituents and, therefore, cellular integrity
§ metals concentrate in protein-rich tissues such as liver and muscle
5. Organic Compounds
§ high toxicity and high persistence in the environment and in biological systems
§ persistent xenobiotic compounds have been found in every part of the ocean: from arctic to Antarctic, and from intertidal to abyssal
§ may disrupt normal metabolism of sex hormones
§ Hydrocarbons interfere in the production and growth of phytoplankton in many ways. Hydrocarbon molecules disrupt the plasma membrane by displacing those of other lipid compounds
6. Plastics
§ marine litter threatens wildlife through entanglement, ghost fishing, and ingestion
7. Sedimentation
§ estimated global sediment load to oceans in the mid-20th century to be 20,000 million tons per year, of which about 30% comes from rivers of southern Asia
§ High levels of turbidity limit penetration of sunlight into the water column, thereby limiting or prohibiting growth of algae and rooted aquatic plants.
§ In spawning rivers, gravel beds are blanketed with fine sediment which inhibits or prevents spawning of fish
§ Many of the persistent, bioaccumulating and toxic organic contaminants, especially chlorinated compounds including many pesticides, are strongly associated with sediment
8. Aquaculture
§ displacing fishing grounds, and adding new species to area they are not naturally found.