Arsenic Contamination in US Public Water Is More Likely in Latinx Communities Tighter federal regulations on the toxic worked to decrease levels in public water, but certain regions and groups remain more at risk. Marilyn Nieves / E+ / Getty Images By A new survey shows arsenic levels in public water are disproportionately high in certain U.S. communities, despite national regulatory standards designed to protect people from the harmful chemical. Researchers studied approximately 13 million records from 2006 to 2011 covering 139,000 public water systems in 46 states, Washington D.C., and Native American tribes. The records cover water service for 290 million people, representing 95 percent of all public water systems and 92 percent of the total population served by public water systems. Researchers found that, while average public water arsenic concentrations decreased by an average of 10 percent nationwide over the time studied, that decrease was not equal across all areas or demographic groups. Arsenic levels remained higher in water systems serving Hispanic communities and areas of the Southwestern U.S. Their findings were published this month in