Zinc content in brass and its influence on lead leaching

Abstract

It has been speculated that lead leaching is related to dezincification, which is characterized by the preferential leaching of zinc from the alloy, leaving behind a porous residue of copper and corrosion products. This increasingly porous layer allows lead to detach and diffuse more rapidly from the brass surface into solution. High‐zinc brasses are usually more susceptible to dezincification attack; therefore, the high‐zinc brasses might be expected to experience more severe lead leaching. This article found that using dezincification‐ reduction (DZR) brasses that minimize dezincification might create increased problems with lead leaching. Therefore, to limit lead leaching, it is important to limit the amount of lead in all brasses or limit the use of leaded brasses. Given recent concerns about failures from dezincification, a forthcoming requirement to mandate DZR brass in some potable water applications (i.e., lower zinc content or DZR resistance from arsenic or other substances) is on the horizon. From the perspectives of public health protection and regulatory compliance, it may be important to limit the lead content of brasses.

POU devices in large buildings: Lead removal and water quality

“…Concentrations observed in field conditions of operation and sampling therefore are likely to be lower and the detection of significant contributions of meters may be more difficult. The extent of Pb release observed in this study and reported by others (Zhang & Edwards, 2011; Elfland et al, 2010) strongly supports the implementation of stringent regulations for new water meters and for brass materials. It also raises the issue of managing the legacy of these installed meters.…”

“…Total Pb levels could not be correlated to total Cu when the basement taps were excluded, although they were correlated with total Zn and Sn. This may indicate brass dezincification (Zhang & Edwards, 2011; Oliphant & Schock, 1996). However, Cu concentrations were correlated to total Pb when the basement taps were included.…”

“…However, the total Pb release observed by Sandvig et al (up to ~ 23 µg/L Pb after 6 h of stagnation, 250 mL) was considerably lower than the findings from this study, and stabilization was achieved at between five months and four years. Even for equivalent Pb levels, marked differences in release could be caused by the tendency of Pb to leach for different types of brass, especially for low‐zinc brass, and variability between meters (Zhang & Edwards, 2011; Sandvig et al, 2008). Higher Pb release could also be the result of high Pb content on the meter's interior surface, because Elfland et al (2010) measured > 18% Pb on the internal surface of low‐zinc ball valves, whereas the exterior surface contained 6.6% Pb.…”

Issues associated with use of dielectrics in drinking water systems

“…Surface potential of the brass nipple might be less noble compared with pure copper because of its elevated zinc content (87% copper, 13% zinc), but this did not translate to a reduction in galvanic corrosion current. Thus, in this water, a slight short-term advantage of higher zinc content in the copper alloy was not detected as was observed in prior research with lead (Clark et al, 2013;Zhang & Edwards, 2011).…”

Potential regulatory implications of Health Canada's new lead guideline

“…The variability in premise plumbing materials and construction can result in unpredictable spikes of lead due to the semirandom release of particulate lead (Masters, Parks, Atassi, & Edwards, 2016;Sandvig et al, 2008;Schock, 1989). Compared with paired 6-h stagnation, higher lead concentrations in some random daytime and 30-min stagnation samples may indicate a sporadic but significant contribution of particulate lead from the premise plumbing; brass fixtures or faucets and lead-tin solder are possible sources in this case (Deshommes, Laroche, Nour, Cartier, & Prévost, 2010;Elfland et al, 2010;Lytle & Schock, 1996;Parks, Pieper, Katner, Tang, & Edwards, 2018;Sundberg, Holm, Hertzman, Hutchinson, & Lindh-Ulmgren, 2003;Triantafyllidou et al, 2007;Zhang & Edwards, 2011;Figure 3). Distinguishing between lead levels due to characteristics of the home (e.g., consistent particulate lead levels from premise plumbing) or sporadic release of lead particles was not possible as each home was only sampled once using the four protocols.…”