engleski

Investigations on lead and cadmium in the soil and ground beetles of a forest ecosystem - a preliminary research

The aim of the study was to determine lead and cadmium concentrations in soil and ground beetles at two sampling sites, in order to find out possible correlation of metals in soil and in beetles. Both sites were located in Lamio orvalae - Fagetum forest in Medvednica Nature Park and chosen based on previous geochemical surveys of area. The ground beetles were sampled by pitfall trapping (using meat as attractant) during the summer (July) in 2002. Specimens were analysed on species level because many authors suggest that for metal accumulation species-specific differences are more important than trophic position. Ground beetles were dry ashed and the soil was extracted with nitric acid. Elements were analysed by atomic absorption spectrometry. Results revealed that two locations were different in lead and cadmium concentrations in extracted soil and ground beetles. Lead concentration in extracted soil was 47.9 mug/g dry weight in the first (S1) site and 34.5 mug/g dry weight in the second (S2) site. Respective cadmium values were 0.47 and 0.31 mug/g. Lead concentrations in ground beetles were 0.601 and 0.317 mug/g dry weight, and cadmium 1.684 and 1.458 mug/g dry weight. These initial results showed that ground beetles were sensitive to soil contaminants such as lead and cadmium. Concentration of xenobiotic metals can not be regulated efficiently like nutritional ones. Although determined by some authors as "deconcetrators" (detoxification of already assimilated toxic chemicals), higher concentrations of cadmium and lead are detected in ground beetles at the site with higher level of toxic metals.

heavy metals; Carabidae; Coleoptera; Croatia

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