The results of this trial showed that crabs exposed to styrene concentrations of approximately 4 ppm for a period of 200 hours exhibited contaminant contents (in the tissues and gills) ranging from 5 to 15 ppm (see Figures 1 and 2).
In addition to these tests, olfactory tests were conducted at the olfactometry laboratory at the French Institute for Nuclear Safety and Protection (IPSN).
The exposure of crabs to styrene was effective as the concentration in their tissues reached up to 24,600 µg/kg. The olfactory results from the IPSN tests showed that the styrene odour can be easily detected in the experimental conditions applied. The control crabs were correctly identified as uncontaminated, while the styrene-exposed crabs were identified as contaminated.
It is therefore possible to reliably detect the presence of styrene by smell at a concentration of 5,000 µg/kg (5 ppm) or more.
In this trial, the contamination period lasted 8 days. Individuals were removed at different times, for analysis and transfer to decontamination tanks. The decontamination phase was also studied for a maximum duration of 8 days.
According to the results obtained by the Rouen laboratory, the exposed crabs showed contamination levels ranging from 10,100 to 22,100 µg/kg for the tissues and 3,200 to 33,000 µg/kg for the gills. The control crabs were not contaminated, with concentrations of less than 1 µg/kg. Following a 144-hour decontamination period after 48 hours and 148 hours of exposure, the styrene could still be detected, with respectively 20 and 121 µg/kg in the tissues.