Metaldehyde removal using innovative biofilms

Metaldehyde is a widely used pesticide, used to protect plants from slugs and snails. You’ve probably even used some yourself if you’ve ever bought slug pellets. However, when it enters water, it is extremely difficult to remove, making it responsible for most of the pesticide related drinking water failures in the UK. It often seeps into water supplies when it rains, so it’s hard to prevent the contamination. Metaldehyde poisoning is often deadly in animals, and moderately toxic by ingestion in humans, causing stomach and intestinal irritation as well as kidney and liver damage. 

 As a result, it is important to find innovative ways to remove it from drinking water. However, creating additional by-products is undesirable, as these require safe disposal, and an energy-intensive method would lead to additional costs. STREAMer Catherine Rolph conducted research to see how effective a film, made from activated carbon and microbes, was in comparison to the standard sand media currently used. 
Introducing the biological activated carbon was found to remove 94% of metaldehyde, however this needs to be regenerated regularly to maintain that level of absorption and therefore is quite limited. Biofilms were found to be less effective with 41% removal, but would work well as a complementary method to current metaldehyde removal, which would not only increase the efficiency and avoid related public health concerns, but do so without raising the cost of treatment and therefore water bills for the consumers.

Full article: 
Metaldehyde removal from drinking water by adsorption onto filtration media: mechanisms and optimisation, CA Rolph, B Jefferson, F Hassard, R Villa, Environmental Science: Water Research & Technology 4 (10), 1543-1552