Metals in the Molluscan Kidney: A Comparison of Two Closely Related Bivalve Species (Argopecten), Using X-Ray Microanalysis and Atomic Absorption Spectroscopy

Abstract

The kidney epithelial cells of Argopecten irradians contain concretions that occur within an apical vacuole in these cells and that have been analyzed in situ by energy dispersive X-ray microanalysis. Pellets of these concretions prepared from A. irradians and A. gibbus were compared by X-ray microanalysis and atomic absorption spectrophotometry; calcium and phosphorus were the major elements present in both species, but A. irradians contained higher amounts of magnesium and lower amounts of manganese and zinc than A. gibbus when expressed relative to calcium content. However, A. gibbus contained a smaller proportion of calcium by weight than A. irradians, and A. gibbus contained much higher levels of Cd, Cu, and Cr than A. irradians. The trace metal content of scallop kidney concretions may be a sensitive monitor of marine metal contamination provided that sufficient base line data are collected and individual, species, seasonal, and geographical variability are taken into account. Key words: bivalvia, kidney, metals, analysis, calcification, morphology