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16 October 2014

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Tania David
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Name: Tania David

Born: 1966, Bridgend

Cynffig Comprehensive School; University College of Wales, Aberystwyth

Forensic scientist Chepstow, Wales

Tania David
Click here to watch interview

Looking for Clues
'No two days are the same in my job as a forensic scientist. In drug investigations you never know what the next case is or what's going to come in.

'Drugs seized by the police are brought to the forensic science service for analysis. Sometimes the police ask us to go and check out a location they suspect is involved in the large-scale production of cannabis. This is one of the most common drugs we encounter.

'The Forensic Science Service is on call 24/7 to help the Police and Customs and Excise look for physical evidence that could link a person to a crime scene: hair and footwear marks, paint fragments, fingerprints, tool marks, examining items for DNA. Nationally, over 1,600 forensic scifiles, in seven regional labs, are part of the force investigating violent crimes, such as rape and murder, volume crimes like burglaries and car crime and, of course, drug offences.

'The most rewarding and satisfying part of my job is the support I can give the criminal justice system by standing up in court and giving evidence - applying science to the law.'

So you want to be a scientist?
'My advice is: Go for it! Don't be deterred by disappointing A level results: I was a late starter and ended up with a first-class honours degree. It's a stimulating career - ongoing scientific developments mean scientific careers are constantly evolving.'

Scientist under the microscope:
What scientific discovery would you save from a burning building?
'DNA Profiling - one of the biggest advances in crime detection and reduction.'

Your favourite bit of kit?
'My laptop: it allows me catch up on work when I'm out of the lab on business.'

The Science
'Three main tools are used to analyse drugs. First, a simple Spot Test - a colour change indicates a particular drug type. Second, Gas Chromatography Mass Spectrometry (GCMS). Sample preparation takes a few minutes and the running time is about 10 minutes. This test gives an unequivocal identification of commonly encountered class A drugs (heroin, cocaine and ecstasy) and class B drugs (cannabis and amphetamine).

'To determine the purity of the drug - concentration - scifiles use High Performance Liquid Chromatography (HPLC). The answer takes just a few hours. Often, the biggest factor in an urgent case is the time needed to recover and prepare the sample. The drugs can arrive wrapped in plastic, paper, cling film or foil. And the entire seizure has to be analysed. If you have 100 wraps it can be laborious extracting the drug from its packaging.

'The final stage in the process is writing up the test results and, if necessary, presenting my statement as evidence in court.'

Where now?
The Forensic Science Service has details of the courses available and qualifications needed to train as a forensic scientist or pathologist

Information on careers in forensic science and pathology and the work of the Forensic Science Society

The BBC cannot accept responsibility for the content of external sites.

Where do Wales' great Scientists come from?


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