A main known culprit causing amnesic shellfish poisoning in humans is domoic acid (DA). The toxin appearance
in sea waters (by counting the toxin producing algae) and consequently in shellfish is closely monitored
to prevent acute intoxications with gastrointestinal symptoms and neurological signs. However it is assumed
that there might be some chronic problems with repetitive exposures to the toxin in animals. In humans this
is greatly unknown and it is mostly assessed by relating reported toxin episodes and representative consumption
data. Although in Belgium no alarming outbreaks have been reported in recent years, different concentrations
of DA have been found in shellfish samples. In this study the human acute and chronic exposure
to DA through shellfish consumption was evaluated by linking the data of DA concentrations in samples
collected in the scope of the National Food control program in the period 2004–2009 and consumption
data obtained from the National Belgian Food Consumption Survey including 3245 adults. The found level
of toxin was highest in scallops while lowest in mussels. The mean usual long-term intake of molluscs
such as scallops, mussels and oysters for the whole Belgian population was from 0.10 g/day for scallops to
1.21 g/day for mussels. With average portion size estimated to be 56–108 g/day depending on the shellfish
source it was calculated that less than 1% of the population would be at risk of acute intoxication. Using a medium
bound approach, 5–6% of the population shows chronic exposure exceeding the tolerable daily intake of
0.075 μg/kg bw per day with scallops being the most probable toxin vector when using lower (68.5%) and
medium (45.6%) bound concentrations.