Terrestrial model food chain and environmental chemicals: I. Transfer of sodium [ 14C]pentachlorophenate between springtails and carabids

A model soil food chain of a ruderal ecosystem has been constructed in order to study the uptake, transfer, and accumulation of [ 14C]pentachlorophenate (PCP-Na). The model was based on three food levels, viz. baker's yeast, collembola, and carabid beetles, and the contaminant chemical introduced was via initial food. Continuous exposure of the organisms to the test chemical resulted in a significant uptake and transfer of radiocarbon into the food chain elecments. Bioaccumulation of radiocarbon in the body tissues of the organisms was low, as large amounts taken up were quickly eliminated through the excrements. The radiocarbon level of prey animals was about 100 times higher than that of their predators, but there was only small difference in concentration between collembolas and yeast. This was probably because of a faster excretion of the chemical by the beetles than by the collembolas. During the test period no conversion of [ 14C]PCP-Na took place in the yeast, but the collembolas and beetles metabolized 50 and 59%, respectively. Criteria are proposed for successful implementation of food chain models.