New Method to Trace Toxic Compounds

Toxic organic compounds of tin, called organotins used as plastic stabilisers, catalysts, preservatives, and anti-fungicides in paints, enter the environment and pose a threat to human health because of their toxicity and long life.

So far, they remained untraced as there was no way to detect organotins in the environment. Now French scientists have found a method that can monitor the paths of these toxic compounds.

The technique, published online in the Journal of Analytical Atomic Spectrometry on January 10, 2007, consists of three steps-extraction of nitric acid from them, turning them into derivatives of the compound (a chemical reaction which converts the existing compound into physically detectable form) and chromatographic separation.

On the ground, after addition of a chemical compound (isotopically-enriched butyltin), the organotins could be estimated with a single analysis. The procedure was successfully tested on three French landfill sites.

"The method can be extremely useful to assess the fate of organotin compounds, providing a specific, reliable and complete understanding of the environmental impact of this kind of effluent," said David Amouroux of the University of Pau in France and one of the authors of the paper.

Organotins are extremely neurotoxic and can cause organ failure. Their ability to interact with fatty surfaces in cells such as cell membranes is thought to be one of the reasons behind this.

Two of the most toxic alkyl tin compounds are trimethyltin and triethyltin. They have been known to cause headache, dizziness, memory loss, hyper excitability and seizures.

Source: Down to Earth, June 2007