Lead (Pb) deposition onto new and biofilm-laden potable water pipes

Md Hadiuzzaman; Nahreen Mirza; Shawn P Brown; David A Ladner; Maryam Salehi

doi:10.1016/j.chemosphere.2023.140135

Lead (Pb) deposition onto new and biofilm-laden potable water pipes

Chemosphere. 2023 Nov:342:140135. doi: 10.1016/j.chemosphere.2023.140135. Epub 2023 Sep 8.

Authors

Md Hadiuzzaman¹, Nahreen Mirza², Shawn P Brown², David A Ladner³, Maryam Salehi⁴

Affiliations

¹ Department of Civil Engineering, The University of Memphis, Memphis, TN, USA.
² Department of Biological Sciences, The University of Memphis, Memphis, TN, USA.
³ Department of Environmental Engineering and Earth Sciences, Clemson University, Anderson, SC, USA.
⁴ Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO, USA. Electronic address: mshfp@missouri.edu.

PMID: 37690561
DOI: 10.1016/j.chemosphere.2023.140135

Abstract

Heavy metals' interactions with plumbing materials are complicated due to the differential formation of biofilms within pipes that can modulate, transform, and/or sequester heavy metals. This research aims to elucidate the mechanistic role of biofilm presence on Lead (Pb) accumulation onto crosslinked polyethylene (PEX-A), high-density polyethylene (HDPE), and copper potable water pipes. For this purpose, biofilms were grown on new pipes for three months. Five-day Pb exposure experiments were conducted to examine the kinetics of Pb accumulation onto the new and biofilm-laden pipes. Additionally, the influence of Pb initial concentration on the rate of its accumulation onto the pipes was examined. The results revealed greater biofilm biomass on the PEX-A pipes compared to the copper and HDPE pipes. More negative zeta potential was found for the biofilm-laden plastic pipes compared to the new plastic pipes. After five days of Pb exposure under stagnant conditions, the biofilm-laden PEX-A (980 μg m^-2) and HDPE (1170 μg m^-2) pipes accumulated more than three times the Pb surface loading compared to the new PEX-A (265 μg m^-2) and HDPE pipes (329 μg m^-2), respectively. However, under flow conditions, Pb accumulation on biofilm-laden plastic pipes was lower than on the new pipes. Moreover, with increasing the initial Pb concentration, greater rates of Pb surface accumulation were found for the biofilm-laden pipes compared to the new pipes under stagnant conditions. First-order kinetics model best described the Pb accumulation onto both new and biofilm-laden water pipes under both stagnant and flow conditions.

Keywords: Biofilm; Heavy metals; Lead; Plastic pipes; Tap water quality; Zeta potential.