Please note: The uncorrected proof of our new journal article has been published online. The final corrected version will be released soon. The existing document has several typographical errors arising from file conversion. A corrected final version of the document is forthcoming. The scientific substance of the uncorrected proof is accurate.
- Dr. Marc Edwards ([email protected]; 540.231.7236)
- Dr. Sid Roy ([email protected]; 540.521.6193; unavailable May 29-June 1 2019)
The lack of valid drinking water lead measurements during the Flint Water Crisis has spurred controversy, speculation and angst about harmful human health exposures. A new research study published in the peer-reviewed journal Water Research, took advantage of routine lead measurements of Flint’s sewage sludge, to gain unprecedented insight to Flint’s drinking water lead levels from 2011-2017. Lead in drinking water is eventually trapped in sewage sludge, that must be analyzed monthly for metals before incineration or disposal, allowing calculation of the total monthly lead mass that is removed during sewage treatment..
“There was an anomalous spike in sewage sludge lead, and by extension the drinking water lead, during three summer months immediately after the 2014 switch to Flint River water—this is the first direct proof that the elevated water lead levels could have caused the increased blood lead of Flint children” first author Dr. Sid Roy stated. The research confirms prior hypotheses of Dr. Mona Hanna-Attisha, the Centers for Disease Control and Prevention and others. “On the other hand, the excess lead in sewage sludge during the 18 months before the public was notified of problems in October 2015, was only 14% higher than the corresponding time period before the switch to Flint River,” Roy noted.
By demonstrating that the water lead spiked in summer 2014, but overall lead release was only slightly increased other time periods, some seemingly contradictory and conflicting research perspectives on the Flint Water Crisis are reconciled. Roy indicated that “There was a marked elevation in water lead summer 2014, temporarily increasing the blood lead of children, but the problems in the other months did not statistically impact lead in sewage sludge or childrens blood lead compared to before the Flint Water Crisis.”
Because lead in biosolids was so strongly correlated to lead levels in Flint’s drinking water, it was possible to estimate Flint’s water lead levels going back to 2011. Roy and his Virginia Tech co-authors Dr. Min Tang and Marc Edwards, indicate that during the worst month of the Flint Water Crisis (June 2014), the 90th percentile water lead level was 77-98 ppb, well over the EPA action level of 15 ppb. Their analysis also revealed that water lead and children’s blood lead levels also spiked in tandem back in 2011, well before the Flint Water Crisis. Roy stated “This indicates that even before corrosion control was abruptly interrupted in April 2014, after the switch to Flint River, elevated water lead was probably a significant issue in Flint.”
The work also allowed for a direct comparison to the Washington D.C. lead in drinking water crisis (2001-2004), that had been previously associated with very high incidence of elevated blood lead in children and even increased fetal death rates in prior research by Edwards. The worst month of the Flint Water Crisis, June 2014, had lead levels in the range of those reported throughout during the D.C. Lead Crisis, but all other months were much lower.
There is also some good news. Roy’s analysis demonstrates that lead in water, lead in sewage, and incidence of elevated blood lead in Flint children are now trending to historically low values. Edwards points out “This provides another set of independent scientific data, demonstrating the effectiveness of the public health interventions including enhanced disinfection, enhanced corrosion control and lead pipe replacement, and the steady improvement in Flint drinking water quality since the switch back to Lake Huron water in 2015.”
Funding agency disclaimer: This research work was partially funded by the U.S. Environmental Protection Agency under Grant No. 8399375 “Untapping the Crowd: Consumer Detection and Control of Lead in Drinking Water.” This research has not been formally reviewed by EPA. The views expressed in the article are solely those of the authors and do not necessarily reflect those of the Agency. EPA does not endorse any products or commercial services mentioned in this publication.