14 July 2005: Road kill assists pollutant monitoring

An animal-friendly scheme for monitoring the spread of toxic brominated fire retardants in the environment relies on the analysis of mammalian hair rather than post mortem tissue samples.

Polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs) are widely used brominated fire retardants (BFRs) that are now so widespread in the environment that they have been proposed as new members of the United Nations’ list of persistent organic pollutants (POPs). One way to estimate their distribution is to measure their levels in local fauna.

Conventional methods for monitoring POPs in mammals hinge on the analysis of their organs and tissues, requiring that the animals be killed. Now, Helga D’Hav? and colleagues at the University of Antwerp, Belgium, have devised a non-destructive method for the analysis of PBDEs and PBBs that uses mammalian hair. They have applied the technique to the European hedgehog. Even during method development, no animals were deliberately killed, as the samples were obtained from road kills and deaths at wildlife rescue centres.

Hair cut from the hedgehog corpses was subjected to acid hydrolysis and organic solvent extraction and the BFR contents in the extracts were measured by gas chromatography/mass spectrometry. For comparison and validation, the levels in adipose tissue, muscle and some organs were also determined.

Although there were differences in the distributions of BFRs between hair and the various tissues, there was a strong positive correlation between total levels in hair and tissues, confirming that hair is a reliable medium for monitoring BFR levels in hedgehogs.

  ’Like other insectivores, hedgehogs are vulnerable to secondary poisoning through ingestion of earthworms, slugs, bugs and caterpillars, some of which are known to accumulate high levels of organic pollutants,’ said D’Hav?. ’Their contamination levels reflect local pollution since they live in relatively small home ranges (approx. 10-30 ha).’

D’Hav? is now measuring BFRs in the hair of live hedgehogs, to assess local pollution as well as the risk to hedgehogs using the hair/organ correlation. Steve Down