Metaldehyde is used worldwide to control slugs and snails in crops. It is a cyclic tetramer of acetaldehyde,poisonous to all forms of animal life,with a lethal dose of 100-300mg/kg. On ingestion it is partially degraded to acetaldehyde,an irritant. In slugs and snails,this results in the production of large amounts of mucus,and partial paralysis. This leaves the animal exposed in the open,and death is by dehydration. Slug pellets are usually formulated with bran,and can be eaten by wildlife and domestic pets. Birds and animals such as hedgehogs may be affected by eating slugs or snails that have ingested metaldehyde. Farmers are subject to regulations restricting the use of metaldehyde. In 2012,levels of metaldehyde in waterways in the UK exceeded EU limits.The picture shows a slug that has ingested metaldehyde. It is stranded and immobile. Behind,a trail of mucus is visible |