Chinese mitten crab is an invasive species in many European rivers and lakes. Data from the UK indicated
high levels of dioxins and PCBs, in particular in the brown meat in the body. This was confirmed by studies
in the Netherlands, showing average levels of dioxins and PCBs in the meat in the body of
43 pg TEQ g1 ww in crabs caught in the large rivers. Levels in crab of lakes in the Northern part of the
Netherlands were on average 3.7-fold lower. Consumption of crabs from polluted areas results in a relatively
high dose of dioxins and dl-PCBs and could significantly increase the intake above the TWI. However,
in general consumption of these crabs is low, even in the Asian sub-population in the Netherlands.
Cadmium and lead levels were higher in crabs from contaminated areas, but for mercury and arsenic
there was no clear difference. Consumption of crabs would not result in significant risks for cadmium and
mercury. For lead the daily intake could be raised above the BMDL01 for neurodevelopmental toxicity, but
this would only occur on a limited number of days. For arsenic the exposure would exceed the lower end
of the BMDL01 values for certain cancers, but again, the infrequent consumption by most consumers
reduces this risk. Furthermore, speciation showed that most arsenic in crabs was probably not a toxic
inorganic form, but likely to be in an organic form.