Researchers are raising concerns that rising sea levels are contaminating fresh drinking water with seawater, which could have the same effect on blood pressure as key cardiovascular risk factors like inactivity. A recent analysis revealed that people who drank saltier water, most often in coastal communities, were 26% more likely to develop hypertension or chronic high blood pressure. This could pose a significant concern for the more than 3 billion people who live near a coast worldwide. The salinity of your drinking water depends heavily on where it comes from. This concern is particularly for coastal dwellers in low- and middle-income countries who rely heavily on shallow wells or groundwater as their main drinking sources. The study author Dr. Rajiv Chowdhury said parts of the Gulf Coast and coastal Louisiana are particularly at risk, as is South Florida, which relies heavily on the Everglades for its drinking water.