Research profiles

Toxic Metals

The Water Institute and partners are undertaking a multi-year collaborative effort to identify, address, and communicate under-recognized harms from lead and toxic metals in drinking water worldwide.

Toxic metals (TMs) such as lead in drinking water cause irreversible cognitive and neurological impairment in children and developing fetuses and contribute to morbidity and mortality at all ages through multiple disease processes. Global exposures to lead and arsenic each account for more than 10 million lost person-years of healthy life and hundreds of thousands of premature deaths worldwide each year. Exposure to other TMs have substantive global disease burdens as well.

In high-income countries, regulatory and engineering solutions have reduced but not eliminated lead contamination in large water systems, while TM contamination remains widespread in private wells and small piped systems. These issues are under-studied in low- and middle-income country (LMIC) settings; however, available evidence suggests TM contamination is widespread in piped systems and point sources.

This issue remains under-recognized because many water systems are only tested at the time of installation but not thereafter (missing effects of corrosion); or tested using methods that miss or underestimate TM contamination, particularly in remote or low-resource settings. As a result, TM occurrence related to water system corrosion may often be missed in many such settings, and harms from TMs in drinking water worldwide may be greatly underestimated and under-addressed.

The Water Institute is working with collaborators to:

  1. build and assemble evidence on the occurrence of TMs in drinking water in US and LMIC settings
  2. establish the salience of this as an under-recognized problem
  3. identify and disseminate suitable preventive and corrective solutions
  4. support adaptation and implementation of such solutions.

These efforts include a three-country study on the occurrence of TMs in over 200 small water systems in West Africa, a rapid review of sources and solutions of TM contamination in drinking water, and presentations to global audiences on these findings.

The Water Institute’s 3-country study in West Africa found that 80% of small rural water systems tested had at least one part with lead levels exceeding international guidelines for plumbing fixtures. Approximately 9% of water samples also exceeded WHO guidelines for lead in drinking water. Systems with lead-containing parts were most likely to have water samples with elevated lead. These findings add to a growing body of evidence from high- middle- and low-income countries suggesting that system-derived TM contamination is widespread in small water systems and is not limited to just a few countries, regions, implementers, or water system types, and suggest that simple and affordable actions can prevent this contamination.

The Water Institute’s recent review of sources and solutions of TM contamination reported that while sources and solutions vary, prevention is widely applicable as the preferred first barrier to TM contamination in drinking water across a broad range of contaminants and sources. Expanded testing and certification of TM-free water system components and materials, in combination with post-construction water quality testing for TMs can support such efforts. Collaborative global, regional, and national responses to TM contamination in drinking water are likely needed to achieve and sustain prevention across multiple contexts.

This collaborative work is being undertaken in partnership with a growing set of global stakeholders including water, sanitation, and hygiene (WaSH) implementers, funders, and government agencies, as well as other researchers and global networks such as the Rural Water Supply Network, and in consultation with stakeholders such as WHO, UNICEF, and others. To date, much of this work has been supported by World Vision.

Future efforts include an upcoming systematic review of TM occurrence in drinking water systems in LMIC settings worldwide, formation of collaborative working groups around tackling TMs in drinking water, and piloting and validating preventive and corrective solution to TM contamination in field settings. In addition, The Water Institute is working to validate and potentially enhance the performance of low-cost field-based methods to detecting and quantifying lead in drinking water.

References:

  • Fewtrell, L. J., Prüss-Üstün, A., Landrigan, P., & Ayuso-Mateos, J. L. (2004). Estimating the global burden of disease of mild mental retardation and cardiovascular diseases from environmental lead exposure. Environmental research, 94(2), 120-133.
  • Fewtrell, L., Fuge, R., & Kay, D. (2005). An estimation of the global burden of disease due to skin lesions caused by arsenic in drinking water. Journal of water and health, 3(2), 101-107.
  • Yang, A. M., Lo, K., Zheng, T. Z., Yang, J. L., Bai, Y. N., Feng, Y. Q., ... & Liu, S. M. (2020). Environmental heavy metals and cardiovascular diseases: Status and future direction. Chronic diseases and translational medicine.