Evaluation of the contamination of marine algae (seaweed) from the St. Lawrence River and likely to be consumed by humans

The goal of the study was to assess the contamination of marine algae (seaw eeds) growing in the St. Lawrence River estuary and Gulf of St. Lawrence an d to evaluate the risks to human health from the consumption of these algae . Algae were collected by hand at low tide, A total of 10 sites on the nort h and south shores of the St. Lawrence as well as in Baie des Chaleurs were sampled. The most frequently collected species of algae were Fucus vesicul osus, Ascophyllum nodosum, Laminaria longicruris, Palmaria palmate, Ulva la ctuca, and Fucus distichus. Alga samples were analyzed for metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn), iodine, and organochlorines. A ris k assessment was performed using risk factors (e.g., RfD of the U.S. EPA, A DI of Health Canada, etc.). In general, concentrations in St. Lawrence alga e were not very high. This was especially true for mercury and the organoch lorines, concentrations of which were very low or below detection limits. C onsequently, health risks associated with these compounds in St. Lawrence a lgae were very low. Iodine concentration, on the other hand, could be of co ncern with regard to human health. Regular consumption of algae, especially of Laminaria sp., could result in levels of iodine sufficient to cause thy roid problems, For regular consumers, it would be preferable to choose spec ies with low iodine concentrations, such as U. lactuca and P. palmata, in o rder to prevent potential problems. Furthermore, it would also be important to assess whether preparation for consumption or cooking affects the iodin e content of algae. Algae consumption may also have beneficial health effec ts. Scientific literature has shown that it is a good source of fiber and v itamins, especially vitamin B-12.(C) 1999 Academic Press.