Energy companies that use hydraulic fracturing to extract natural gas use a lot of process water. They’re left with recovered water containing high levels of pollutants, including benzene, bromide, and the heavy metals barium and strontium. The firms can reuse the water, but in some cases they inject it into deep storage wells or send it to local treatment plants. A study has found that water flowing out of treatment facilities still has elevated levels of fracking pollutants (Environ. Sci. Technol., DOI: 10.1021/es301411q). Kyle J. Ferrar and his colleagues at the University of Pittsburgh analyzed water leaving three treatment plants in Pennsylvania before and after the facilities complied with a state request to stop processing fracking wastewater. The team found that levels of contaminants dropped significantly after the plants stopped taking the water. But when the plants still handled it, concentrations of several of the chemicals exceeded EPA drinking water standards. For example, at one facility, strontium levels were on average 48.3 mg/L, which exceeds the 4 mg/L standard. Ferrar says there is no immediate public health concern over the pollutant concentrations, but he thinks the elevated levels could affect aquatic ecosystems downstream of the treatment facilities.