Total arsenic and inorganic arsenic contents were determined in 153 samples of seafood products consumed in the Basque Country (Spain): fish (white fish and blue fish), mollusks, crustaceans, and preserved fish. White fish presented higher levels of total arsenic and lower levels of inorganic arsenic than the blue fish, indicating possible differences in the metabolization of inorganic arsenic. For total arsenic, 66% of the samples exceeded the maximum permitted level by the strictest international legislation in seafood products [1 microg g(-)(1), wet weight (ww)]. The levels of inorganic arsenic were considerably lower than the maximum authorized in New Zealand (2 microg g(-)(1), ww), the only country with legislation for inorganic arsenic in fish and fish products. It is recommended that legislation based on levels of inorganic arsenic should be established.

Total and inorganic arsenic contents were analyzed in cooked seafood products consumed in Spain during the period July 1997-June 1998: hake, meagrim, small hake, anchovy, Atlantic horse mackerel, sardine, bivalves, crustaceans, squid, and salted cod. Various cooking treatments were used (grilling, roasting, baking, stewing, boiling, steaming, and microwaving). The results obtained were compared statistically with those found previously in the same products raw, and they showed that after cooking there was a significant increase in the concentration of total arsenic for salted cod and bivalves, and in the concentration of inorganic arsenic for bivalves and squid. The mean content of inorganic arsenic was significantly higher in bivalves than in any other type of seafood. For the Spanish population, the mean intake of total arsenic estimated on the basis of the results obtained in this study is 245 microg/day. The intake of inorganic arsenic (2.3 microg/day) represents 1.7% of the World Health Organization provisional tolerable weekly intake (PTWI), leaving an ample safety margin for this population, which has a very high consumption of seafood.

The organoarsenical species arsenobetaine (AB), arsenocholine (AC), tetramethylarsonium ion (TMA+), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) were determined in 64 cooked seafood products (fish, bivalves, squid, crustaceans) included in a Total Diet Study carried out in the Basque Country (Spain). For cooking, various treatments were employed (grilling, roasting, baking, stewing, boiling, steaming, microwaving). The results obtained show that in cooked seafood AB is the major species, followed by DMA and TMA+. AC and MMA are minor species. The results in cooked seafood were compared with the arsenic species contents obtained for the same product raw. After cooking there was an increase in DMA for sardines and bivalves and an increase or appearance of TMA+ for meagrim, anchovy, Atlantic horse mackerel, and sardine. The data provided add to the very scant information available about organoarsenical species contents in cooked seafood.