Arsenic Species Analysis in Wool of Sheep and Human Hair

Hair and wool are part of the body metabolism and during their growth are influenced by the presence of toxins and drugs. The fibre is formed in the root; during which time there is a possibility of the inclusion of, for example arsenic species. Since hair proteins contain a large amount of sulfhydryl groups, and trivalent arsenic species have a high affinity to these groups, there is a high probability that these highly reactive arsenic species are enriched in hair. Trivalent arsenic species are under suspicion that they are highly carcinogenic, but their concentration in most body fluids is too low to measure them. Therefore hair and wool might be suitable materials to increase our knowledge about the metabolic changes of ingested arsenic species. To test this hypothesis we extracted wool from sheep feeding on seaweed (contains large amounts of organic bound arsenic) and human hair samples from people drinking arsenic contaminated well water. The fibres were extracted with water by boiling for 6 hours. After filtration the extracts were injected onto a HPLC column connected with an inductively coupled plasma mass spectrometer. For the identification of the separated species we used spiked samples. We-were able to identify As(III), As(V), monomethylarsonic acid (MMA(V)) and dimethylarsinic acid (DMA(V)) in extracts of both kinds of fibre. The wool extract contained also monomethylarsonous acid (MMA(III)) and dimethylarsinous acid (DMA(III)). In addition to these identified species the wool extract contained a further four unidentified species.