Thermo-mechanical processing of brass components for potable-water usage increases risks of Pb leaching
K W Siu1, J C M Kwok1, A H W Ngan1
1Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Water Research
|September 18, 2020
Summary
Thermo-mechanical processing of brass piping increases surface lead, raising concerns for lead contamination in drinking water. Common installation practices may require revised protocols to mitigate risks.
Area of Science:
- Materials Science
- Environmental Science
- Public Health
Background:
- Lead contamination in potable water remains a global concern.
- Existing explanations for lead leaching from brass, such as corrosion, are insufficient.
- Mechanical and thermal processes can cause lead segregation on brass surfaces.
Purpose of the Study:
- To investigate the impact of thermo-mechanical processing on lead segregation in brass.
- To assess the subsequent leaching of segregated lead into contacting water.
- To evaluate the risks associated with common brass piping installation and maintenance procedures.
Main Methods:
- Simulating thermo-mechanical processes like milling, polishing, and flame-torch treatment on brass.
- Analyzing surface lead concentration after processing.
- Correlating lead leaching with plastic deformation of the brass surface.
Main Results:
- Mechanical milling and polishing significantly increased surface lead levels.
- A strong correlation was found between lead leaching and plastic deformation.
- Flame-torch treatment, simulating brazing, also led to increased surface lead.
Conclusions:
- Common thermo-mechanical processing of brass piping components poses a significant risk of lead contamination.
- Current protocols for handling brass components may need revision.
- Further research into safer handling and installation practices is warranted.
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