For many people pollen is nothing but the signifier of a sneezy summer season and hay fever, but for forensic investigators it has now become an unlikely crime fighting tool, which could help determine what happened when a crime was committed.
This branch of forensic science is called palynology, and it uses pollen to determine a host of factors not always obvious in crime scene investigations.
One of South Africa’s handful of pollen analysts, based at the University of Cape Town (UCT) Lung Institute, is Dr Dilys Berman, who said the future is bright for this field, but that more funding is required to take full advantage of palynology at a national scale.
“With so many high-profile cases involving forensic palynology and environmental analysis now receiving publicity, the future of this branch of forensic science is certain,” she affirmed.
“The development of multi-disciplinary approaches to environmental analyses of crime scenes mean that far more detailed information can be made available to law enforcement agencies, enabling them to determine with greater accuracy what may have happened at the time the crime was committed,” Berman explained.
Forensic pollen analysis has been used in a number of cases for at least 60 years that would otherwise have gone unsolved.
The most famous forensic palynology case took place in Austria, after a man inexplicably disappeared. The man was presumed dead because detectives could not find a body, but they did have a suspect and a pair of muddy boots.
A palynologist analysed the shoes and found a 20-million-year-old fossil of hickory pollen, which only grew on a tree on the Danube River. Detectives disclosed the information to the suspect, who subsequently told investigators where to find the body.
“The pollen found in a wreath in Tutankhamen’s tomb helped to fix the date of his internment, while pollen on the shroud of Turin helped to determine its origin to Gethsemane, where a certain type of pollen species has bloomed for millennia.”
Berman said palynology can solve a number of crimes, including forgery, illegal drugs, assault, robbery, rape, murder, genocide, terrorism and arson.
“It can also be used to resolve various types of civil cases, such as the authentication of paintings, fake antiques, forged documents, removal of artefacts from historic or archaeological sites, illegal pollution of the environment or the poaching of animals and fish.”
Pollen grains are incorruptible pieces of evidence that can stay at the crime scene longer after the fact, Berman explained.
“The fact that they are small, highly variable and found on almost anything that has been exposed to or interacts with the air, make them ideal forensic trace materials.
“Pollen grains can be isolated from soil, rope, clothing, drugs, air filters, plant material, animal and human material such as fur, hair or stomach contents, by using forensic tools.”
Each region also has its own pollen fingerprint, which can remain on clothes even after they are washed.
Palynology may be the proverbial silver bullet in fighting crime, but it is pricey, and in South Africa, there are only a handful of scientists capable of identifying pollen.
Palynologists need a Ph.D., as well as knowledge of ecology, botany, pharmacology, geology and climatology, Berman explained.
And in order for palynology to thrive, a large pollen database is needed, to process and reference pollen samples taken at crime scenes.
Countries such as the UK, parts of Europe, the US, Australia and New Zealand regularly rely on palynology, but much to the annoyance of hay fever sufferers and palynologists alike, a database like this does not exist in South Africa yet.
“Forensic palynology is complex and can be expensive, which is why in SA, it is often used as a last resort,” Berman said.
“Knowing what plants are flowering when and recording that data doesn’t just help doctors and hay fever sufferers to manage allergy symptoms, but it also assists in solving crime and tells us how we are impacting our environment and climate.
“By analysing pollen from well-dated sediment cores, scientists can record changes in vegetation going back millions of years.”
But funding is needed now, due to climate change influencing plants’ migration patterns, which makes tracing them more challenging for palynologists.
Pollen is also changing due to rising temperatures and pollution, which Berman said modifies their molecular structure.
It is possible to establish such a database, especially after the launch of UCT’s Lung Institute in 2019. Berman said the institute “has been doubly useful in uniting pollen experts from across the country”, which is a step forward in adopting palynology as a norm in forensic investigations.
“As the number of cases that pollen is successfully used as evidence increases, the range of its potential uses also increases.
“With more funding, we will be able to install sufficient pollen sampling units in each region to give us more accurate pollen counts and data to work with when called upon to solve forensic cases,” she said.
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