Forms of arsenic in tuna fish tissue
dried, homogenised and sterilised tuna fish muscle tissue
The tuna fishes were obtained from the city of Venice following to their classification as being excessively contaminated by mercury and consequently removed from the fish market. Mercury contamination is typically correlated to arsenic contamination due to the joint origin of these elements from submarine volcanic activities in the Mediterranean basin. The tunas were fished in the strait of Messina, wqere kept frozen at Venice for approximately four weeks, dissected and the dorsal muscles were isolated. The latter were minced and freeze-dried. The freeze-dried tissue was ground in a zirconium dioxide mill, passed over a 125 µm sieve and the fraction > 125 µm, being of extremely fibrous nature, was discarded.
The fraction < 125 µm was collected and homogenized in a special PVC mixing drum filled with dry argon. The homogenized powder was sub sampled and tested for bulk homogeneity by XRF, for a nujmber of minor and key trace elements. Having reached the required bulk homogeneity level, the material was further homogenized for 24 h and put into dry brown glass bottles, primarily flushed with dry nitrogen and then sterilized by irradiation (60Co) at 8 kGy. In total about 1000 bottles were filled.
keywords: biological material , animal tissue , foodstuff , fish/shellfish , speciation analysis , arsenic speciation