Salinity/Dissolved Salts


Salts are minerals that dissolve in water. They include Sodium (Na+), Chloride (Cl-), Sulfate (SO4-3), Potassium (K+), Magnesium (Mg+2 ), and Calcium (Ca+2). These are present in higher concentrations in seawater than in freshwater. That is why seawater is called saltwater.


Why does it cause pollution?

In normal quantities these substances are not harmful and some even act as plant nutrients. Farmers often add magnesium, potassium, calcium or sulfate to soil to promote healthy plant growth. But too much of a good thing can be BAD!

During drought these dissolved chemicals become concentrated and can poison or dehydrate plants and animals. For instance, fresh water plants will sometimes die during a drought if salinity increases too much in the surrounding water.


How does it get into water?

In Salinity/dissolved salts get into the water when they dissolve in rainwater from rocks and soils. Then they become runoff, and enter nearby waterbodies. this is a natural process that has made seawater salty over hundreds of millions of years. However, when fertilizers are added to agricultural soil, an excessive amount can enter runoff and pollute the water.

Also, many waterbodies in ocastal areas become polluted when seawater, which is naturally salty, can move upstream into fresh water areas. This may happen when there have been flow alterations or drought.. This process is known as saltwater intrusion.


What land uses are the source of this type of pollution in the B-T Basin?

  • Drought
  • Agricultural Runoff
  • Flow Alteration
  • Natural Sources

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