Influence of ecological factors on accumulation of metal mixtures

Abstract

A very large number of experimental studies in aquatic ecotoxicology have been devoted to the assessment of metal uptake in different classes of living organisms. Most of them are based on analysis of single toxicants, despite the fact that under field conditions the biota is generally exposed to multicontaminant pollution. In addition to producing a direct response in biota, a toxic metal can also act by interfering with other metal ions or elements. Thus, the concurrent presence of two or more metallic contaminants in the organism often yields metal uptake that deviates from those currently observed for individual metals. If the effect is an enhancement of bioaccumulation, it is said to be synergistic. If the effect is a decrease of metal incorporation, it is said to be antagonistic.Most of the knowledge about metal-metal interactions has been acquired in mammalian species. In such species, the major source of metals is the diet and metal uptake depends on the physicochemical forms of storage of metals in food organisms (Amiard-Triquet et al., 1993;Dallinger, 1993). In these conditions, interactions occur inside the organism and changes may be expected at the level of toxicant uptake, distribution, storage and excretion. Biochemical processes such as competitive affinities for intracellular ligands or co-accumulation as mineral granules are probably predominant. In the case of aquatic organisms, interactions can occur both inside organisms (as in mammals) as well as outside through changes of metal speciation, distribution between soluble and insoluble phases and finally bioavailability. Great differences have been detected in metal body burdens when different species (or even different populations within the same species) were compared (Rainbow, 1993). If the species or populations that accumulate the most are Metal Metabolism in Aquatic Environments. Edited

Interactive Effects of Copper, Cadmium and Lead on Zinc Accumulation in the Gastropod Mollusc Littorina Saxatilis

“…As a result of their chemical affinities, Cd and Zn may share similar uptake pathways into organisms (Rainbow, 1997). It has been similarly observed that in many molluscan species, exposure to the non-essential metal Cd had no effect on Zn accumulation; whereas exposure to essential metal Zn had an antagonistic effect on Cd accumulation (Amiard-Triquet and Amiard, 1998). Littorinids are generally considered to be good indicators of contamination with dissolved Cd (Stenner and Nickless, 1974;Manga and Hughes, 1981;Bryan et al, 1983).…”

Uptake and Efflux of Cd and Zn by the Green Mussel Perna viridis after Metal Preexposure

“…Interaction between Cd and Zn kinetics have been demonstrated but are often inconsistent and contradictory (44). For example, Cd uptake decreases (not statistically significant) in M. galloprovincialis at 100 µg of Zn L -1 (45).…”

Multimetal Interactions between Cd, Cu, Ni, Pb, and Zn Uptake from Water in the Zebrafish Danio rerio

“…Uptake of metals in mixtures may demonstrate competitive and noncompetitive inhibition and in some cases enhanced uptake . The type of interaction depends on the metals involved, their external concentration, availability and exposure scenario, length of exposure, studied species, and examined organs , . The existence of metal−metal interactions occurring at low, environmentally relevant concentrations has been reported for different crustacean , and fish species , .…”