First Do No Harm: The Need to Explore Potential Adverse Health Implications of Drinking Rainwater

S eawater intrusion of coastal aquifers has caused potable water scarcity in coastal communities of Bangladesh the problem is especially severe in southwest coastal Bangladesh. 1 Global warming is expected to aggravate the condition due to rising sea levels and more frequent and stronger cyclones.High drinking water salinity has contributed to high salt intake and hypertensive disorders among population in southwest coastal Bangladesh.Pregnant women drinking groundwater have higher prevalence of preeclampsia and gestational hypertension compared to those drinking rainwater or pond water. 2 The estimated intake of sodium is 5-16 g/day in the dry season when the population relies on groundwater while the World Health Organization (WHO) recommended daily intake is less than 2g for adults (http://www.who.int/mediacentre/news/ notes/2013/salt_potassium_20130131/en/).The potable water scarcity problem is largely seasonal, with the main challenge occurring during the dry season between November and early May.Due to less rainfall and decreased river flow, salinity of surface water bodies such as rivers and canals increases during the dry season.Moreover, ponds often dry up during dry season leaving people with few or no alternatives but to extract saline groundwater using hand pumps for drinking and cooking purpose.During the wet season (May-October), communities usually collect rainwater through household-or community-level rainwater harvesting systems and use it for drinking and cooking purposes.Rainwater has a very low content of sodium and other minerals.