Evaluating Water Lead Levels During the Flint Water Crisis

Abstract

In April 2014, the drinking water source in Flint, Michigan was switched from Lake Huron water with phosphate inhibitors to Flint River water without corrosion inhibitors. The absence of corrosion control and use of a more corrosive source increased lead leaching from plumbing. Our city-wide citizen science water lead results contradicted official claims that there was no problem- our 90th percentile was 26.8 μg/L, which was almost double the Lead and Copper Rule action level of 15 μg/L. Back calculations of a LCR sampling pool with 50% lead pipes indicated an estimated 90th percentile lead value of 31.7 μg/L (±4.3 μg/L). Four subsequent sampling efforts were conducted to track reductions in water lead after the switch back to Lake Huron water and enhanced corrosion control. The incidence of water lead varied by service line material. Between August 2015 and November 2016, median water lead reduced from 3.0 to <1 μg/L for homes with copper service lines, 7.2-1.9 μg/L with galvanized service lines, and 9.9-2.3 μg/L with lead service lines. As of summer 2017, our 90th percentile of 7.9 μg/L no longer differed from official results, which indicated Flint's water lead levels were below the action level.

Reflections on the Lead and Copper Rule and Lead Levels in Flint's Water

“…This is despite the fact that there were biases in the data, as the sites sampled were not representative of Flint housing stock (Goovaerts ). Even the 90th percentile values for the residential testing and that reported by Pieper et al (), which include data from non‐Tier 1 sites, are reasonably consistent with those testing programs where the sites are believed to be all Tier 1. There is a decline in the 90th percentile values over time and after fall 2016, the 90th percentile WLLs were consistently below the AL of 15 μg/L.…”

“…The data presented by Pieper et al () are shown in Figure . The 90 percentile levels for the independent testing ( n = 144) are also shown in Figure .…”

“…As documented in detail by Pieper et al (), five system‐ wide sampling campaigns were conducted in August 2015, March 2016, July 2016, November 2016, and August 2017. The sample kits were distributed by a team of Flint residents, led by Walters, throughout the city.…”

“…In August 2015, Marc Edwards and a group of Virginia Tech students resampled the water in Walters’ house (Pieper et al ). They also participated in an extensive sampling event organized by a group of Flint residents (as described by Pieper et al ). This study found that water lead levels (WLLs) exceeded 15 μg/L in 85% of the first‐draw samples taken.…”

“…Serious water quality problems arose in Flint, Mich., in 2014, after the City of Flint began distributing treated Flint River water from the Flint Water Service Center (FWSC) to the community. This is commonly referred to as the “Flint water crisis,” which has been documented in numerous publications including books (Clark , Hanna‐Attisha ), reports (USEPA , Michigan Civil Rights Commission ), and peer‐reviewed publications (e.g., Abernethy et al , Gómez et al , Goodwill et al , Pieper et al ).…”