CDC investigation: Blood lead levels higher after switch to Flint River water

“The Centers for Disease Control and Prevention (CDC) today released the results of its investigation into the potential health impact that lead contamination in the Flint, Michigan water supply had on the blood lead levels of local children. The findings indicate that when the source of the water supply was switched to the Flint River, without appropriate corrosion control measures, young children who drank the water had blood lead levels (BLLs) that were significantly higher than when the source of water was the Detroit water system. After the switch back to the Detroit water system, the percentage of children under 6 years with elevated blood lead levels returned to levels seen before the water switch took place. “This crisis was entirely preventable, and a startling reminder of the critical need to eliminate all sources of lead from our children’s environment,” said Patrick Breysse, Ph.D., director of CDC’s National Center for Environmental Health. “CDC is committed to continued support for the people of Flint through our Childhood Lead Poisoning Prevention program and efforts to raise awareness and promote action to address the critical public health issue in communities across the country.” To understand the impact of consuming contaminated drinking water on children’s blood lead levels, CDC researchers examined data on levels of lead in blood of children younger than six years before, during, and after the switch in Flint’s water source. The current CDC blood lead level of concern (also known as a reference level) is 5 or more micrograms of lead per deciliter of blood (≥5 µg/dL). This reference value is based on the population of children ages 1-5 years in the U.S. who are in the top 2.5% of children tested for lead in their blood. From April 25, 2014, to October 15, 2015 (the period when the Flint River was used for drinking water), the levels of lead in Flint tap water increased over time and analysis of children’s blood lead data detected an increase in BLLs ≥5 µg/dL. The likelihood that a child consuming the water would have a blood lead level ≥5 µg/dL was nearly 50 percent higher after the switch to Flint River water. CDC continues to recommend that all children under age 6 living in the City of Flint have their blood tested for lead by a health care provider, particularly if they have not had a blood lead test since October 2015. All children with BLLs ≥5 µg/dL should receive evaluation and follow up, including a home assessment for sources of lead, and health and developmental assessments. The CDC study had limitations. Researchers were not able to account for all of the factors that might have contributed to a child’s exposure to lead, including whether lead-based paint was present in the child’s living environment. In addition, researchers did not have information on the amount of lead in or the amount of water consumed by the tested children, limiting the analysis to evaluation of changes in blood lead levels over time as the source water changed…”