Arsenic

Ceramic water filters are used in many parts of the world as simple water purification technologies, and local clay often provides the source for production of these filters. We've been working with several organizations along the Mekong River of Cambodia and Laos to test the clay for arsenic levels. Arsenic is found at relatively high levels along the Mekong watershed, having washed down during natural erosive processes from the Himalayan Mountains. Arsenic in this clay has the potential to be a health hazard if enough were to leach into the water being passed through ceramic water filters. We use atomic absorption spectrophotometry to measure arsenic in clay samples.

Funding for AAS instruments was provided by a major NSF CCLI grant.

Major findings:

1. Arsenic concentrations in clay do vary with location, and ranged from 4.6 to 19.9 ug As/g clay.

2. Iron concentrations in clay was moderately correlated with arsenic concentrations. No other elements showed significant correlations.

3. Arsenic concentrations in clay from Laos (Pakse area) ranged from 0.72 to 5.54 ug/g.

Future Research:

• We are interested in determining at what rate, and how much, arsenic leaches from clay filters.
• We continue to monitor arsenic in clay samples and provide this information to organizations who are choosing locations for clay sources.

1. Arsenic in clay samples from Cambodia:

2. Correlation of arsenic content with iron, manganese, and other elements

3. Arsenic in clay from Laos