Sediment Samples (IMAGE) Columbia Climate School Caption Samples of clay and aquifer sand cuttings collected at five-foot intervals near the study site in Bangladesh. Grey sand is often associated with elevated arsenic in groundwater and orange sand consistently with low arsenic in groundwater. Credit Rajib Mozumder Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.