Drinking water in New Orleans, Louisiana (NOLA) has traditionally been considered a minor source of lead exposure, as it continues to meet the action level outlined in the Lead and Copper Rule (LCR). Residents concerned about water lead levels (WLL) are encouraged by health officials and water utilities to flush the tap for 30 seconds to 2 minutes to reduce exposure. Our recent investigation has shown that WLLs are not significantly reduced, and in some cases may inadvertently increase lead exposures. With continued consumption, these sustained, low-level lead concentrations may be detrimental to public health. Between 2015-2016, 315 households participated in a complimentary water testing effort. Water lead levels in first-draw samples prior to flushing ranged from &lt;1 to 46 µg/L (mean=2.7 µg/L; median=1.4 μg/L). There is no significant difference between WLLs in the first draw sample, with WLLs in the 30 second flush (median=1.6, singed rank test p-value=0.553) and 2-minute flush (median=1.2, p-value=0.079). This indicates that the prevailing exposure reduction guidelines may be inconsistently effective. Evaluation of other metals suggest that WLLs in the flushed samples may be associated with lead service lines. This is supported by the lack of strong WLL correlation with common corrosion metals associated with other sources (iron, copper, zinc). The EPA’s Integrated Uptake Biokinetic Model estimates that 6-12% of children living in homes in NOLA may be at risk for elevated blood lead above the CDC reference level of 5 µg/dL, based on the 10<sup>th</sup> and 90<sup>th</sup> percentile WLLs, respectively. The results from this investigation provide insights to assist public health officials and water utilities in outreach to low-income communities who may rely on this guidance. Results may also inform EPA revisions to the Lead and Copper Rule [40 CFR 141.85]; and spur changes to EPA’s Consumer Confidence Report Rule [40 CFR 141.154] - both of which require messaging about flushing in public outreach materials.

Evaluation of prevailing flush guidelines to reduce water lead exposures: Implications for regulations and public health outreach

253rd National Meeting (2017)

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