Joel Johnson, Yr 12 Term 4 EEI 4.2, Task A, 1/11/16 Page 1 of 3
Forensic Palynology
Introduction
Forensic palynology (pollen analysis) is the study of pollen and spores, applied to solving legal issues.
It has been used as a forensic tool for over 50 years, but has only recently become a more widely
used technique (Mildenhall, Wiltshire & Bryant 2006).
The basis of palynology comes from the unique characteristics of pollen. Owing to their hard,
durable coating, pollen grains are a long-lasting form of evidence. Pollen is ubiquitous, being found
wherever plants are, and is easily transferred to clothing, people or other objects. Being microscopic,
a suspect will not know that pollen has been transferred onto them, and the grains are difficult to
completely remove, even by washing (The Forensics Library n.d.).
Collection and Analysis
Evidential pollen samples can be collected from virtually any object, including people, clothing and
parts of vehicles, e.g. wheels, mudguards, air filters. Samples can be taken using a soft sable brush,
cellophane tape, a portable vacuum cleaner, or other methods (Bryant, Jones & Mildenall 1990).
Comprehensive site surveys and photographs of the crime scene or suspected area(s) need to be
taken, in order to determine the plant species in the area and their relative abundance. Botanical
reference samples of each plant should also be collected, if possible. Ideally, the palynologist will be
among the first to the crime scene, to prevent the contamination of pollen samples.
Control samples, which represent the typical pollen makeup of the crime scene, are usually taken
from topsoil in the surrounding area. The collector must ensure that sufficient control samples are
taken, and that they reflect the typical composition of the area. The evidential samples are later
compared to the control samples; the closer their similarity, the higher the chance that they came
from the same area.
All samples should be stored in sterile, airtight containers such as Ziploc bags, and labelled with a
unique identification number. A record must be kept of the chain of custody of each sample in order
for it to be presented as legal evidence (including who had it at what time, and the conditions under
which the container was opened). Avoiding contamination between when a sample is collected and
when it is examined by the palynologist is of the utmost concern (Bryant, Jones & Mildenhall 1990).
Damp samples must be dried in an oven before being stored in a fridge or freezer, as mould or fungi
may otherwise destroy the samples. Any plant material for identifying the vegetation in the area
should be pressed and dried.
Recovering pollen from a sample can be done several different ways, so the method used should be
chosen at the discretion of the palynologist. However it typically includes removing mineral and
organic matter through acid treatment, sieving, and staining to view the pollen grains (Korejwo et al
n.d.). As it is usually a destructive technique, pollen analysis should be the last analysis conducted on
a sample (Bryant, Jones & Mildenhall 1990).
Pollen analysis is usually conducted under a light microscope, however SEM (Scanning Electron
Microscopy) and QEMSCAN (Quantitative Evaluation of Minerals by SCANning electron microscopy)
may be useful, or even necessary, in some cases. Pollen grain size can provide some identification
