Bioaccumulation of Metals in Sediment Elutriates and Their Effects on Growth, Condition Index, and Metallothionein Contents in Oyster Larvae

Abstract

The bioavailability of Cd, Cu, Zn and Pb from two metal-contaminated sediment (Bidassoa and Dunkerque) was studied using Crassostrea gigas larvae exposed to sediment elutriates. The metal contents within the sediments, the larvae and larval growth, the condition index, and the induction of metallothionein in the larvae were measured. The larval growth and condition index were only affected after exposure to the highest elutriate concentration (5 to 25%) from the most contaminated sediment (Dunkerque). Bioaccumulation of all metals was observed in larvae exposed to Dunkerque elutriatre and only Cu bioaccumulation was observed in the case of Bidassoa elutriate. The compilation of results from larvae exposed to both sediment elutriate show a strongly correlation between bioaccumulated metal considered individually or combined and metallothionein level in larvae presenting no detrimental effect.In contrary, in the case of larvae exposed to the highest Dunkerque elutriate concentration and showing the highest metal body burdens, we observed a drop of the metallothionein level.These results indicate that metallothionein is a more sensitive indicator of heavy metal pollution, compared to physiological endpoints taking into account in bioassays and could be proposed as precocious biomarker of metals exposure in larvae. However, it must be take care to the "fault control" due to toxicological effect on larvae metabolism in the case of important contaminant exposure.3

Effect of chronic exposure to zinc in young spats of the Pacific oyster (Crassostrea gigas)

“…Another study showed that adult oysters exposed to zinc concentrations ranging from 0.0153 to 1,529.1 mM for 48 h exhibited a specific protein expression pattern at each concentration [35]. Protein increase in oysters after zinc exposure has also been demonstrated [4,5,11], including larvae [12]. Limitations in the amount of material did not allow replicates, but the RNA extracts corresponded to numerous pooled individuals.…”

“…The effects of chronic exposure to zinc on filtering bivalves have been previously investigated by several authors who focused on bioavailability, tissue accumulation, transfer kinetics, and relationships with metallothionein [4][5][6][7][8][9]. Numerous studies have addressed early life stages and toxicity [7,[10][11][12][13][14][15][16][17], most of which involved larvae. A major issue regarding zinc is its chemical speciation in the natural marine environment and the consequences for its bioavailability, especially for filter-feeding animals.…”

Effects of glyphosate-based herbicides on embryo-larval development and metamorphosis in the Pacific oyster, Crassostrea gigas

“…In marine bivalves (oysters and mussels), often considered as sentinel organisms for coastal environments, embryo-larval stages are used in ecotoxicological studies. Some previous studies have examined larval growth or condition index (Brereton et al, 1973;Geffard et al, 2007); the activities of different enzymes, including those implied in oxidative stress regulation (Damiens et al, 2004;Quiniou et al, 2007); and the integrity of DNA (Jha et al, 2000;Hagger et al, 2005;Cheung et al, 2006;Wessel et al, 2007). Finally, many of the ecotoxicological studies using marine bivalve larvae have mainly evaluated the embryotoxic effects of various pollutants (Robert et al, 1986;His et al, 1999;Nice et al, 2000;Lyons et al, 2002;Libralato et al, 2008;Cachot et al, 2006;Akcha et al, 2012).…”

Biomarkers of damage and protection in Mytilus galloprovincialis cross transplanted in Ria Formosa Lagoon (Portugal)

“…Transplanting molluscs from a reference site to a polluted area should be considered as a feasible strategy for monitoring the effects of environmental changes in coastal or estuarine zones (Da Ros et al 2000;Geffard et al 2007;Bebianno et al 2007). Ria Formosa Lagoon, the largest lagoon on the Portuguese south coast, is an important tourist area being under several pressures that have contributed to the water quality deterioration.…”