The relative sensitivity of growth and reproduction in the springtail, Folsomia candida, exposed to xenobiotics in the laboratory: an indicator of soil toxicity.

The Folsomia candida reproduction test [ISO, 1998. Soil quality--Inhibition of reproduction of Collembola (Folsomia candida) by soil pollutants. International Standard Organization Report 11267, 1998, Geneva] is used to evaluate the ecotoxicological risks of contaminants in soils. The aim of this study was to compare the sensitivity of growth and reproduction of F. candida to four xenobiotics: two metals (Cd, Al), one metalloid (As), and one organic compound (pentachlorophenol). We showed that reproduction is a slightly more sensitive parameter than growth: EC(20) for reproduction was 1.25 microg/g dry soil for arsenic, 56 microg/g for cadmium, 97.5 microg/g for aluminum, and 41.7 microg/g for pentachlorophenol. The corresponding EC(20) values for growth were 2.8, 65, 630, and 94.6 microg/g. Keeping in mind that a growth test needs fewer juveniles and less time than a reproduction test, we conclude that the two parameters are complementary and could be used for a better ecotoxicological evaluation of contaminants. However, the relative growth and reproduction sensitivities should be tested with more chemicals before growth could be considered as a good alternative for a faster sublethal test.