Distribution patterns of chalcogens (S, Se, Te, and Po-210) in various tissues of a squid, Todarodes pacificus

Abstract

In order to elucidate the relationship between the chemically similar chalcogen elements S, Se, Te, and Po-210 in marine invertebrates, we conducted a comparative study of the distribution patterns of these elements in a squid, Todarodes pacificus. Elemental concentrations of the four chalcogens were determined in (mantle) muscle, gill, stomach, and hepatopancreas tissues. No relationship between chalcogen concentrations and morphological parameters (mantle length, body weight, and sex) was evident. Gills showed slightly elevated levels of Se and Po-210, which may indicate absorption and uptake of these elements over the gill surface. All four chalcogens have their highest concentrations in the hepatopancreas and the lowest concentrations in the muscle tissue. However, concentration differences between tissues, revealed by (1) bioaccumulation values based on reference seawater values and (2) internal relative enrichment factors (IREF) based on enrichment of hepatopancreas compared to muscle tissue, were least pronounced for S, most distinct for Po-210, and moderate for Se and Te. Furthermore, no significant correlation for Se, Te, and Po-210 with S within tissue concentrations, and only a slightly negative correlation between S and Po-210 in the squid muscle and hepatopancreas tissues were found, which indicates either an antagonistic effect between, or a disconnection of the two elements through metabolic processing. overall, the distribution patterns of Se and Te resemble those of essential trace elements, such as Zn and Cu, whereas Po-210 is partitioned in a manner similar to toxic heavy metals, such as Cd and Ag. (C) 2007 Elsevier B.V. All rights reserved.