Seasonal Selenium Variations in Mussels and Oysters from a French Marine Farm

Abstract

Selenium (Se) is an essential element for humans. Seafood is generally considered as a good source of Se. This element is principally present in the form of selenate, often easily bioavailable. but its availability can also be quite low in some species. The seasonal variations of Se (concentration and burden) in mussels ( Mytilus edulis) and oysters ( Crassostrea gigas) were examined from November 1982 to May 1984. The molluscs were sampled in a shellfish farm located in the Bay of Bourgneuf (France). Se concentrations in oysters were lowest in samples collected from September to November and highest in samples collected from April to July. In mussels, Se concentrations in the various organs were highest from February to June and lowest from July to October. Se quantity per individual peaked from February to mid-June, while minimum values were found from July to January. From a nutritional point of view, a consumer will ingest approximately six times more Se with mussels from February to June (2 to 13 μg Se · g −1) and only twice as much with oysters except from the September–November period (3 to 6 μg Se · g −1). In the case of oysters, the consumer ingests a fixed number of individuals and on this basis, Se intake via oysters is highest from April to July (2 to 18 μg Se per oyster). According to the season, the intake of Se with oysters varies from 1.3 to 14 μg per day and per consumer. In the case of mussels, these variations range from 6.4 to 13.3 μg per day and per consumer.