Effectiveness of point-of-use and pitcher filters at removing lead phosphate nanoparticles from drinking water

WATER RESEARCH

卷:201

Article

Dore, Evelyne¹  Formal, Casey²  Muhlen, Christy³  Williams, Daniel³  Harmon, Stephen³  Pham, Maily³  Triantafyllidou, Simoni³  Lytle, Darren A.³ 

[1] US EPA, Off Res & Dev, Ctr Environm Solut & Emergency Response, Water Infrastruct Div,Drinking Water Management B, Cincinnati, OH 45268 USA

[2] US EPA, Off Res & Dev, Ctr Environm Solut & Emergency Response, Water Infrastruct Div, Cincinnati, OH 45268 USA

[3] US EPA, Off Res & Dev, Drinking Water Management Branch, Ctr Environm Solut 6Emergency Response,Water Infr, 26 W Martin Luther King Dr, Cincinnati, OH 45268 USA

关键词: Lead;    Colloidal particles;    Nanoparticles;    Orthophosphate;    Pitcher filter;    Point-of-use filter;    Drinking water;   

DOI  :  10.1016/j.watres.2021.117285

来源: Elsevier

【 摘 要 】

Orthophosphate (PO4) addition is a common corrosion control treatment used to lower lead (Pb) concen-trations at the consumer's tap by forming relatively insoluble Pb-phosphate (Pb-PO4) minerals. However, some Pb-PO4 particles that can form in drinking water are mobile nanoparticles (i.e., 0.001-0.1 mu m) that have the potential to reach the tap. Point-of-use (POU) or pitcher filters are often used to manage risks during distribution system upsets, when corrosion control treatment is not optimized, or following Pb service line replacements. To abide by industry convention, POU and pitcher filters must be NSF/ANSI-certified for Pb reduction (NSF/ANSI-53) using a test water containing dissolved Pb and large Pb particles. Certification for particulates reduction (NSF/ANSI-42) is done using a test water that contains particles, but not leaded particles. To address the lack of testing for Pb nanoparticles, this study challenged six certified commercially available faucet-mounted POU (3) and pitcher (3) filters with aqueous suspensions of Pb-PO4 nanoparticle. For the water quality investigated, the Pb particles formed ranged between 0.016 and 0.098 mu m, based on scanning electron microscopy, transmission electron microscopy, and dynamic light scattering analysis. These particles represented 98.5% of total Pb in suspension. The total Pb re-movals were between 44.6 and 65.1% for the POU filters, and between 10.9 and 92.9% for the pitcher filters. The electron microscopy results confirm that Pb-PO4 nanoparticles passed through the filters. The findings can inform future efforts to re-examine the test waters used in the certification challenge tests. Published by Elsevier Ltd.

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