April 2018 - Plants in Forensic Science
Members of the Horndean & District U3A met for their regular monthly meeting on Friday 6th April 2018 at Merchistoun Hall. They were entertained by Dr Michael Keith-Lucas by giving a fascinating talk on Plants in Forensic Science. Dr Michael Keith-Lucas is an expert plant scientist with an extensive knowledge of pollination of plants. He is also involved in woodland history, especially prehistoric clearance, pollen studies on archaeological sites, in plant taxonomy, forensic sciences & allergy collaborative links. His current research projects are pollen analysis of archaeological sites in the Thames Valley.
His interest in pollen extends to its preservation in peat systems giving the historical record of plant colonisation after the ice ages and its recent use in forensics to relate pollen on clothing to the location of an incident. Recently he has been working with the University of Newcastle using pollen identification to see how far bumble bees are travelling and the variety of plants they visit, essential information to inform the protection of essential pollinators. Pollen and pollinators are essential for the survival of the majority of plants on earth and most of our food plants. They provide a record of plant succession over the centuries and a short term record of use to forensic science.
Dr Keith-Lucas explained that based on pollen analysis and sediment composition it has been found that most of our ancient woodlands are virtually the same as those that existed in Anglo Saxon times and found unchanged since Neolithic times. Archaeologists became interested in his work and he was invited to travel around the country to visit digs for ancient remains. They allowed him to go into the excavations to take soil samples to analyse and to find out what was grown in the fields etc.
Following a Viking being found on Orkney with a spear through his vertebral column he was asked to identify when he had died by taking pollen from his nose. The forests in Orkney had been long gone before his death and the area was covered in a blanket of peat which has no insects or worms in it so there was no interference to the body from them. From the grass pollen still in his nose he was able to ascertain that he had died in July.
Whilst in a pub in London, a colleague of his happened to meet a couple of CID officers who needed to identify the date of death of a body that had been found in a sealed box - no flies/maggots etc had contaminated it so they were unable to do their usual tests. They requested his help and he was able to identify the week, month and even whether am or pm of his death because pollen always retains its features. This led to his work in forensics. The Met Office has a superbly accurate records system in the UK, 24/7, of the pollen count in the air we breathe - useful to hay fever sufferers.
Dr Keith-Lucas displayed a pollen calendar which showed that yew was the first in the year to shed its pollen and the different plants throughout the year. Overall there is a wasteful over-production of pollen with just 1 in a million successfully pollinating. There are 50 thousand to a square centimetre produced per year! There are many shapes and sizes of pollen, all identifiable, with different methods of distribution, by air, water and insect. He also produced a picture taken from microscope images of lots of pollens, all remarkably different.
By pollen not losing its features it is a powerful technique in forensics being able to identify date and time of death and can also be used to identify clothing and shoes being present at the scene of a crime. Currently Dr Keith-Lucas is working on honey fraud. There are strict rules set by the EU on pollen percentage of the specified flower to be present in the honey. Lime must have 15% whereas heather must have 80%. Manuka honey from New Zealand is considered to be a great healer because it produces anti bacterial hydrogen peroxide. It must have a rating of 15+, anything below 10 would have no more benefit than any other honey. However because of its high value many of the Manuka honeys have been found to be fraudulent and have been removed from shops in UK.
There were many more interesting stories/facts from Dr Keith-Lucas (too many to include here) and there was no doubt that the members thoroughly enjoyed his talk, followed by many questions.
Diane Stoner
Speaker Coordinator