Water securityComparing technologies to remove arsenic from groundwater

Published 6 February 2019

At least 140 million people in 50 countries have been drinking water containing arsenic at levels above WHO guideline. A new study compares for the first time the effectiveness and costs of many different technologies designed to remove arsenic from groundwater.

A United Nations University study compares for the first time the effectiveness and costs of many different technologies designed to remove arsenic from groundwater — a health threat to at least 140 million people in 50 countries.

Released Monday by UNU’s Canadian-based Institute for Water, Environment and Health, the report draws on 31 peer-reviewed, comparable research papers published between 1996 and 2018, each describing new technologies tested in laboratories and / or in field studies.

And while no single technology offers a universal solution, the research helps point to remedies likely to prove most economical and efficient given the many variables present in different locations worldwide.

Serious health, social and economic losses are caused worldwide by arsenic-contaminated water and a wide range of technologies exists to remove it but “their widespread application remains limited.”

From 2014 to 2018, over 17,400 arsenic-related publications were published and “there is a myriad of reportedly ‘low-cost’ technologies for treating arsenic-contaminated water. But the specific costs associated with these technologies are rarely documented,” says Duminda Perera, a Senior Researcher at UNU-INWEH and a co-author of the report.

UNU-INWEH says that the summary of costs and effectiveness of the few dozen arsenic remediation technologies that are directly comparable in those respects (table: http://bit.ly/2MpVWaa) can serve as a preliminary guideline for selecting the most cost-effective option, he says. It may also serve as an initial guideline (minimum standard) for summarizing the results of future studies describing arsenic remediation approaches.

The report notes that “arsenic-removal technology should only be seen as efficient if it can bring the water to the WHO standard” (in 2010, WHO’s recommended a drinking water limit of 10 µg/L — micrograms per litre), but countries with resource constraints or certain environmental circumstances (e.g., typically high arsenic concentrations in groundwater) have much higher, easier-to-reach concentration targets.