The invasive crayfish Cherax quadricarinatus facing chlordecone in Martinique: Bioaccumulation and depuration study

The redclaw crayfish, Cherax quadricarinatus, was introduced to Martinique Island for aquaculture purposes at
the beginning of the 21st century, in an attempt to revitalize the freshwater crustacean aquaculture sector.
Mainly due to its high economical value, it was intentionally released in the wild and was caught and sold by
fishermen. Martinican rivers are polluted by chlordecone, considered as one of the worst Persistant Organic
Pollutants (POP). Despite its dangerousness, it was used until 1993 in the French West Indies against a banana
pest and was always found in the ecosystems. This study aimed to investigate the level of contamination in the
muscle of crayfish caught in the wild, as well as the potential of bioconcentration and depuration in the
C. quadricarinatus muscle. This study could allow us to quantify the risk for consumers but also, to evaluate a
depuration process to reduce the risk related to its consumption. Using both in-vitro and in-situ experiments,
results highlighted the importance of the chlordecone concentration in the water and the time of exposure to the
pollutant. The bioconcentration seems to be very quick and continuous in crayfish muscle, as chlordecone can be
detectable as early as 6 h of exposure, whatever the concentration tested. Finally, it appears that, even after 20
days of depuration in chlordecone-free water, chlordecone concentrations remained higher to the residual
maximum limit (i.e. 20 ng/g wet weight), concluding that the decontamination of the muscle seems not very
efficient, and the risk for the Martinican people could be serious.