Autori: Dragos V Nica, Marian Bura, Iosif Gergen, Monica Harmanescu and Despina-Maria Bordean
Editorial: Chemistry Central Journal , 6:55, 2012.
Copper (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).Results
Significantly 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.
The 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.
Cuvinte cheie: heavy metals, snail, food chain, risk assessment