Marian Bura

Bioaccumulative and conchological assessment of heavy metal transfer in a soil-plant-snail food chain

BackgroundCopper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) can pose serious threats to environmental health because they tend to bioaccumulate in terrestrial ecosystems. We investigated under field conditions the transfer of these heavy metals in a soil-plant-snail food chain in Banat area, Romania. The main goal of this paper was to assess the Roman snail (Helix pomatia) usefulness in environmental monitoring as bioindicator of heavy metal accumulation. Eight sampling sites, selected by different history of heavy metal (HM) exposure, were chosen to be sampled for soil, nettle leaves, and newly matured snails. This study also aimed to identify the putative effects of HM accumulation in the environment on phenotypic variability in selected shell features, which included shell height (SH), relative shell height (RSH), and whorl number (WN).ResultsSignificantly higher amounts of HMs were accumulated in snail hepatopancreas and not in foot. Cu, Zn, and Cd have biomagnified in the snail body, particularly in the hepatopancreas. In contrast, Pb decreased when going up into the food chain. Zn, Cd, and Pb correlated highly with each other at all levels of the investigated food chain. Zn and Pb exhibited an effective soil–plant transfer, whereas in the snail body only foot Cu concentration was correlated with that in soil. There were significant differences among sampling sites for WN, SH, and RSH when compared with reference snails. WN was strongly correlated with Cd and Pb concentrations in nettle leaves but not with Cu and Zn. SH was independent of HM concentrations in soil, snail hepatopancreas, and foot. However, SH correlated negatively with nettle leaves concentrations for each HM except Cu. In contrast, RSH correlated significantly only with Pb concentration in hepatopancreas.ConclusionsThe snail hepatopancreas accumulates high amounts of HMs, and therefore, this organ can function as a reliable biomarker for tracking HM bioavailability in soil. Long-term exposure to HMs via contaminated food might influence the variability of shell traits in snail populations. Therefore, our results highlight the Roman snail (Helix pomatia) potential to be used in environmental monitoring studies as bioindicator of HM pollution.

Use of Land Snails (Pulmonata) for Monitoring Copper Pollution in Terrestrial Ecosystems

The term bioindicator defines organisms that respond to a pollutant load with changes in vital functions or accumulate pollutants (Arndt et al. 1987). The use of bioindicator organisms may allow researchers to evaluate the effects of mixtures of pollutants on ecosystems in time and space, depending on the selected species and approach (Hellawell 1986). In contrast, simple instrumental analyses of pollutants can provide extremely precise data about their accumulation in organisms, but they do not clearly reveal how different chemicals interact when they cooccur in complex mixtures (Maynard 2004). Bioindicator organisms are often used in environmental monitoring programs “to assess the condition of the environment, to provide an early warning signal of changes in the environment, or to diagnose the cause of an environmental problem” (Dale and Beyeler 2001). Such studies are designed to mirror the quality of natural environments and can either be passive, when bioindicator organisms are native inhabitants of the ecosystem, or active, when organisms of a known biological past are inserted into the site to be monitored (Markert 2007).