Lead Particle Size Fractionation and Identification in Newark, New Jersey’s Drinking Water

Abstract

Following a pH reduction in their drinking water over a span of more than 20 years, the City of Newark, New Jersey, has struggled with elevated lead (Pb) release from Pb service lines and domestic plumbing in the zone fed by the Pequannock Water Treatment Plant. In response, Newark initiated orthophosphate addition and provided faucet-mounted point-of-use (POU) filters and pitcher filters certified for Pb and particulate reduction under NSF/ANSI Standards 53 and 42 to residential homes in that zone. Water chemistry analysis and size fractionation sampling were

Understanding Failure Modes of NSF/ANSI 53 Lead-Certified Point-of-Use Pitcher and Faucet Filters

“…The Newark, NJ, water had relatively low ionic strength and hardness values, expected to reduce particle removal efficiencies by granular media due to increased electrostatic repulsive forces between particles and the filter medium. , Consistent with this expectation, the effluent lead level was >15 μg/L for all four POUs when exposed to the LIS water with an average influent lead level of 991.4 ± 54.7 μg/L. Specifically, the new duplicate POUs had effluent lead levels of 19 and 29 μg/L (97–98% removal), whereas the CD filters had effluent lead levels of 123 and 181 μg/L (81–87% removal).…”

“…The highest influent lead levels in the Flint, MI, and Newark, NJ, field studies were 4080 and 1680 μg/L, respectively, and virtually none of this lead was soluble. ,, Samples with >1000 μg/L lead inevitably become a focal point of media attention and filter performance testing. ,,,, In this testing phase, the POUs were exposed to the Particulate water and two newly created particulate challenge waters (Table S2). The “High-Particulate” water had 1000 μg/L of suspended lead phosphate (>99.9% particulate), with a pH of 8.5 and an alkalinity of 100 mg/L as CaCO 3 .…”

“…Hundreds of thousands of point-of-use filters (POUs) have been distributed to consumers during lead-in-water crises to provide safe potable water and protect public health. − These POUs were lead-certified under the NSF/ANSI 53 standards to reduce the level of influent lead of standardized challenge waters from 150 to <10 μg/L until 2019 and to a threshold <5 μg/L effective in 2020. , Previous lab and field studies have demonstrated that POUs treating water contaminated with >1000 μg/L lead usually produced water with <5 μg/L lead. − However, in field validation testing of water samples from Newark, NJ, and elsewhere with ≤1670 μg/L lead, POUs had >15 μg/L effluent lead and in a few cases >100 μg/L. , Follow-up investigations in Newark indicated that 97.5% of properly installed and operated POUs were producing effluent with <10 μg/L lead, but the sporadic failures nonetheless caused citywide angst, distrust, and a switch to bottled water. − To understand why NSF/ANSI 53 lead-certified POUs occasionally produce effluent water with >10 μg/L lead, we explored POU failure modes due to manufacturing issues, operation beyond rated capacity, and challenge waters with higher particulate lead concentrations.…”

Impacts of orthophosphate-polyphosphate blends on the dissolution and transformation of lead (II) carbonate

“…Colloidal lead-phosphate was reported to have caused the failure of point-of-use filters in Newark, New Jersey 41 .…”

Preventing leaching from lead water pipes with electrochemistry: an exploratory study

“…Over many years of use, Pb water pipes slowly develop a layer of protective scale consisting of Pb corrosion products that limit Pb solubility, including PbO2 and Pb(II) minerals, such as pyromorphite and +cerussite, among others 2 . However, this scale is sensitive to water oxidizing conditions and thus, changes in water quality may lead to an increase in Pb solubility, resulting in toxic levels of Pb being released into the drinking water [3][4][5] . Chronic exposure to Pb has serious adverse health effects, particularly in children, including irreversible damage to the central nervous system 6 .…”