Poisoned Sediment (IMAGE) Earth Institute at Columbia University Caption High concentrations of arsenic are making their way from the Red River into aquifers near Hanoi, Vietnam, a new study shows. Mason Stahl tests water at the river's edge where sediment is being deposited. Credit Courtesy Mason Stahl Usage Restrictions Credit must be given. 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.