Frontiers in Marine Science (Jun 2014)
The effects of heavy metals in the lipids of a marine gastropod - a biomarker approach
Abstract
Fatty acids are carbon-rich compounds that are ubiquitous in all organisms and relatively easy to metabolize. Once incorporated in the organism, their biological specificity and the fact that they are transferred from primary producers to higher trophic levels without changing in characteristics, make fatty acids suitable for use as biomarkers. Different fatty acids have been found in mollusk species. These are influenced by taxonomic relations, environmental conditions, nutrient habits, food availability and also physiological conditions. Heavy metals are among the most common environmental pollutants with natural or anthropogenic presence that can be easily biomagnified through the food chain. They can be toxic above a critical concentration that depends on the organism, the physicochemical properties of the metal, and the environmental factors. Marine gastropods are known to accumulate high metal concentrations in their tissues. Gibbula umbilicalis has abundant soft tissues which enables biochemical assessments and makes this particular organism a potential suitable species to be use in environmental risk assessment (ERA) studies. This work aimed to assess fatty acid profile changes in the gastropod G. umbilicalis exposed to metal contaminants. For that, the organisms were exposed for 168 hours to three different metals: Nickel (Ni), Cadmium (Cd) and Mercury (Hg). The 168h LC50s were 4,27 mg of Ni/L, 2,67 mg of Cd/L and 0,41 mg/of Hg/L. After the sublethal 168h exposure, lipid related endpoints measured were: 1) total lipid content; 2) lipid peroxidation; 3) fatty acid profile. The shifts in the fatty acid profile after exposure to metals’ sublethal concentrations are addressed and discussed in terms of their function and relevance, and this endpoint signature proposed as a novel tool to be used in ERA of coastal environments, using a sea snail as model species.
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