Science - November 6, 2012

Evidence in hair

PhD student Wilco Duvivier of the Laboratory of Organic Chemistry joins the age-old fight against crime by searching for hardened cannabis users who are willing to part with their head of hair.

Cannabis user Koos Koets has a rich head of hair.
What do you want to do with the hair of cannabis users?
'My research is meant to be applied in forensic research later on to examine a person's drug use in detail. It's been known that if you take cannabis or other drugs, traces of these can end up in your hair. Head hair grows by about a centimetre a month. If you analyze a piece of it, you can see when the last time was when that person took drugs. Currently, we cannot determine this with great accuracy.'
And your research will change that?
'That's the aim. In a court of law, hair is often dismissed as unrealiable evidence, because the drugs may be on the hair, but not inside it. We want to make this evidence stronger by looking for the best method to wash off impurities from hair, and to determine more accurately when cannabis is used. We are also going to find the best way to store hair samples, such as in room temperature or in the refrigerator, in light or in darkness.'
Did you get many responses?
'Yes, more than expected. Almost 10 responses. We put up a poster with our announcement at a coffee shop, and sent mails to people in our department to be distributed further. A number of respondents backed out when they realized that they have to be shaved completely , but fortunately, the rest don't mind.'
Will it work doing this with cannabis? Doesn't drug abuse often involve hard drugs?
'It's true that cannabis is not the most dangerous or illegal drug. Certainly not in the Netherlands. The best way would be to feed someone a certain amount of cocaine or heroin at given times. But that is forbidden, of course. That's why we have chosen cannabis to be a model system. Perhaps other drugs also end up in hair via the same mechanism, and we would then be able to comment on them as well.

Re:act