Compartmentation and effects of lead (Pb) in the collembolan, Folsomia candida

The impact of soil lead (Pb) pollution on survival, growth, and reproduction of the collembolan,Folsomia candida, and Pb compartmentation in its gut and remaining body parts were studied by exposing animals to laboratory-spiked soil. The survival, growth, and reproduction ofF. candidawere significantly reduced by increasing soil Pb concentration. The LC(50)values of survival based on total and CaCl2-extractable Pb concentration in soil were 2562 mg kg(-1)and 351 mg kg(-1), respectively. The EC(50)values of reproduction were 1244 mg kg(-1)and 48 mg kg(-1), respectively. The Pb concentration in whole body, gut, and remaining body parts was significantly increased with the increase of soil Pb concentration and followed an exponential increase when the soil Pb concentration was equal to or above a threshold (1000 mg kg(-1)for whole body and remaining body part, 500 mg kg(-1)for gut). Below this threshold, these relationships were linear. The Pb concentration in the gut was higher than whole body and remaining body part ofF. candida, and the threshold of internal Pb concentration at whichF. candidacan compensate was in the range 7-13 mg Pb kg(-1)dry animal (corresponding to soil Pb concentration 500-1000 mg Pb kg(-1)dry soil). The results indicate that reproduction ofF. candidawas a more sensitive indicator of lead toxicity than survival and growth. Pb was mainly accumulated in the gut ofF. candida.We discuss the internal Pb concentration as an indicator of adverse effects in the risk assessment of soil Pb pollution.