Sodium Concentration in Potable Ground Water in Coastal Belt of Bangladesh Due To the Effect of Global Warming: A Potential Health Risk

Abstract

The sea level rise due to global warming is a major environmental issue. It is a burning concern for the countries having coastal belt around the world and Bangladesh would be one of the most affected country. Taking the above facts into concern, our thesis study was undertaken particularly to find out the relation of sodium content with distance from the sea, depth of tube well, seasonal variation and daily dietary sodium intake safe limit. The study was based on two inland sites (Nawabganj and Faridpur) and two coastal sites (Laxmipur and Patiya). Deliberate study of the Tube well sampling of Patiya and Laxmipur at varying depth found that salt intrusion increases with the increase in depth. In Patiya, all tube wells were deep tube wells since the potable aquifer is found below 600 ft. This phenomenon confirms the salt water intrusion is higher through deeper aquifer in Paitya. We assessed that due to ground water recharge from both deep percolation and increase in contributing stream flow from Karnafully River in Chittagong district, the salinity intrusion is lowered in monsoon. Our Analysis of the BGS database of sodium in well water shows that for the inland district Nawabganj and Faridpur, the sodium concentration within the W.H.O. recommended limit of 25 mg/L. American Water Works Association (AWWA) reports that normally the dietary intake of sodium from fresh water is limited to 3 to 5% (U.S. Environmental Protection Agency, 2003; American Water Works Association, 1999), and the potential sodium daily intake from the waters of Nawabganj and Faridpur were found in line to that reported by AWWA. Our sampling study and analysis of tube wells and ponds in Patiya Upazilla which is nearer to coast had much higher concentration of sodium than the W.H.O. recommended limit. This is putting the mass people of Patiya Upazilla and the surrounding zone in risk of cardiovascular diseases and also in risk of developing hypertension.