Isopods as indicators of the copper content of soil and litter

In two species of isopods (mainlyTracheoniscus rathkei, plus a fewOniscus asellus) total copper content as well as the amount of copper extractable with zinc-dibenzyldithiocarbamate in CCl₄ (CTC) were determined. Both copper fractions show near perfect relationship with total copper concentration of the litter collected in the isopods' habitats. Between copperrich and copper-poor sites in Tirol, Austria, mean total copper content of the isopods varies by a factor of 7, mean CTC-extracted copper by a factor of 140 (Table 2). With the exception of one, particularly impoverished, site the concentration of copper in the CTC-extracted compartment reflects the total copper concentration of the food of the animals. Both copper fractions increase with the weight of animals, but the proportionality factor of the increase is three times larger for total copper than for CTC-extracted copper.A simplified geological map of Tirol is given in which the relationship between copper content of soil and litter and of the isopods at selected sites is indicated.