Impact of Seawater Intrusion on Groundwater in Kanchipuram District, Tamil Nadu Coastal Area

Saltwater intrusion is a global issue that affects the coastal areas worldwide. Due to this intrusion, it will affect the growth of crops, soil fertility, and human health. The current study estimates parameters such as Water Quality Index (WQI), Human Health Risk Assessment (HHRA), Seawater Mixing Index (SMI), and Irrigation efficiency (IE) in order to examine the groundwater quality of Kanchipuram district, Tamil Nadu coastal area. A total of 60 sampling stations were considered to examine groundwater quality. For the groundwater analysis, the physicochemical parameters were taken into account. Q-GIS has been used in mapping the sampling locations and affected areas. WQI was calculated for the Kanchipuram based on the physicochemical characteristics of water namely pH, Electrical Conductivity, Total Dissolved solids, Total Hardness, Calcium, Magnesium, potassium, chlorides, fluorides, nitrates, and sodium. From the WQI results it is observed that out of 60 stations, it was observed that around 30% of groundwater is above good quality and around 42% is very poor and not suitable for consumption. The WQI states that groundwater in Kanchipuram district was moderately polluted. SMI was also calculated, it was observed that out of 60 stations SMI values of 23 stations were above 1, i.e., in 38% of stations SMI value was observed to be high. Also calculated HHRA, it was observed in 13% of stations fluoride content is greater than 1 in children. The analysis shows that the impact of fluoride content in children is higher than in adults. Irrigation Indices conclude that 65% of sampling stations have SAR values greater than 10 mEq/L and 58 stations have Na% less than 80%.