Salinity. sulphate, SO 4

Transcription

1 is an indication of the concentration of dissolved salts in a body of water. The ions responsible for salinity include the major cations (calcium, Ca 2+ ; magnesium, Mg 2+ ; sodium, Na-; and potassium, K-) and the major anions (carbonates, CO 3 2- and HCO 3 2- ; sulphate, SO 4 2- ; and chloride, Cl - ). The level of salinity in aquatic systems is important to aquatic plants and animals as species can survive only within certain salinity range. Although some species are well-adapted to surviving in saline environments, growth and reproduction of many species can be hindered by increases in salinity. There are two kinds of salinity dryland and irrigation salinity. Both involve water management and the need to maintain the right balance or equilibrium. (dry land) - Dryland salinity occurs when salt stored in the soil profile over thousands of years is brought to the surface or close to the surface by rising groundwater levels. Dryland salinity is classified as either primary or secondary. Primary salting occurs naturally while secondary salting is induced by human activities such as agriculture. The ultimate outcome of dryland salinity is the discharge of saline water to streams and soils, commonly occurring when saline groundwater rises to within two metres of the ground surface. (irrigation) - Irrigation salinity resembles dryland salinity, except that groundwater accession is induced through irrigation water rather than rainfall alone. Irrigation salinity refers to an accumulation of salt in the plant root zone or on the soil surface, commonly as a result of saline groundwater rising within two metres of the ground surface. Salt sources are consistent with those that occur in the process of dryland salinity and include cyclic salts, salts derived from old marine sediments or from the weathering and breakdown of rocks in soil formation. Effects on Environment and Human Health An elevated is not a health hazard. The concentration is a secondary drinking water standard and therefore is regulated because it is more of an aesthetic rather than a health hazard. Remedial Measures can be removed by reverse osmosis, along with other total dissolved solids. Other removal methods like distillation and deionization can also remove salinity.

2 Figure 22.1: Spatial variation of in Kerala s surface water

3 Water Classification according to 0-450mg/L = Freshwater mg/l = Brackish water mg/l = Saline water Surface water Remarks Sampling site in brackish water condition is: Location Value District Kuppapuram Alappuzha

4 Figure 22.2: Spatial variation of in Kerala s well water

5 Water Classification according to 0-450mg/L = Freshwater mg/l = Brackish water mg/l = Saline water Well water Remarks Sampling sites in brackish water condition are: Location Value District Ponnani Palakkad Guruvayoor Thrissur Chavakkad Thrissur Kollengode Palakkad Veeyapuram Alapuzha Placimada Palakkad Aluva Ernakkualm Kothamangalam Ernakkualm Guruvayoor Thrissur Koodungalur Thrissur

6 Figure 22.3: Spatial variation of in Kerala s tap water

7 Water Classification according to 0-450mg/L = Freshwater mg/l = Brackish water mg/l = Saline water Tap water Remarks Sampling sites in brackish water condition are: Location Value District Thathampally Alappuzha Cherananllur Thrissur Kalikulam Junction Alappuzha