Brackish water is found where ocean or marine water meets with freshwater from rivers such as in estuaries.
An estuary is a junction where a river flows into the ocean.
It is an intertidal zone containing partially fresh and salty water. Many estuaries have been modified by human activities with about 80% of the pollution in estuaries and coastal areas coming from land-based sources.
Causes of pollution in estuaries
Causes of pollution in estuaries or coastal areas include:
- The large human population is mainly within or close to coastal areas: a third of the world’s population lives within a hundred kilometers of a coastline.
- Read Also: Framework for Water Pollution Control
- Use of large quantities of fertilizers that runoff surplus reactive nitrogen and phosphorus.
- Increase in impermeable surfaces (e.g. concrete floors, tarred parking lots) promote runoff of several pollutants.
- Destruction of coastal wetlands by filling, and draining for construction reduce space for water absorption, groundwater recharge, and absorption of pollutants.
- Coastal waters are stressed by pollution, and fisheries and wildlife populations are affected.
