title: Healthy homes need healthy water
title: toward a lead in water risk assessment tool
titleType: Subtitle
Creators: name: Land, Danielle Elizabeth
Publisher: name: University of Iowa
Year: 2023
Subjects: Blood lead level
lead exposure risk
Lead in drinking water
water lead exposure risk
Water lead risk assessment
public abstract
Corrosion

description: Exposure to lead is a systemic inequity and despite public health policies reducing lead burdens, lead remains one of the most important housing-related hazards to children. Reducing or eliminating sources of lead in the environment before exposure occurs (i.e., primary prevention) is the most reliable and cost-effective measure to protect children from lead poisoning. To better understand the factors contributing to lead in water risk, I have used data-driven methods to evaluate what factors drive the risk of lead exposure from drinking water. My goal is to create a water lead risk score (WLRS) that can be used to assess the risk of people being exposed lead from drinking water in their homes. I first evaluated the association of spatially interpolated blood lead levels (BLLs) in Flint, Michigan with service line type (i.e., lead, copper, galvanized) before and during the water crisis. I found that even when controlling for age of housing, LSLs and galvanized iron pipes were both independent risk factors for BLLs ≥ 2 µg/dL before and after the switch to the Flint River water. I also found that the odds of having predicted BLLs ≥ 2 µg/dL doubled in all homes after the switch to Flint River water, including those with full copper service lines. My findings are consistent with findings that removing LSLs will likely reduce children's exposure to lead in water. However, my findings also provide epidemiological evidence that water lead contamination will likely remain even after LSLs are removed, suggesting that additional work will be needed to continue to identify and mitigate lead in drinking water hazard.
description: I then evaluated the association of corrosion-related metals and phosphate in homes with lead service lines and homes with full copper service lines in Flint, Michigan to determine if specific water lead sources could be identified. These correlations suggest two distinct sources of lead contamination during the FWC – premise plumbing and lead service lines. Although LSLs were more likely than copper lines to lead-in-water guidelines, a large proportion (78%) of first draw lead samples in homes with full copper lines still exceeded 1 ppb and 9.2% exceeded EPA's action level (AL) of 15 ppb, indicating the presence of lead contamination even in homes with no known LSL.
description: Finally, I evaluated the extent of potential lead exposure that is missed by relying on the 90th percentile approach used in LCR compliance. The 90th percentile approach allows up to 10% of lead samples taken by a water system to exceed 15 ppb with no additional action required. To evaluate the extent of potential lead exposure that is missed by relying on a 90th percentile approach, we collected and analyzed over a decade of LCR reports in Iowa (n = 4,117), Nebraska (n = 2235), Louisiana (n = 4775), and Georgia (n = 8386). We found that using 95th percentile value rather than the 90th percentile to evaluate whether the EPA's 15 ppb AL was exceeded resulted in 1.9 to 4.8 times more exceedances depending on the state. Our findings highlight that using just a few more data points to characterize lead levels in a community water system can make a significant difference in whether the water system exceeds the EPA LCR action level. With required sampling rates that are already too low to be statistically representative of a water system, we advocate for using the more stringent 95th percentile approach to evaluate whether action is needed.
description: My hope is that this improved understanding of the factors influencing lead-in-water risk, a water lead risk score can be developed to help public health and government officials strategically direct resources to the most appropriate and effective interventions before lead contamination occurs - because healthy children need healthy water.