Collembola reduce their body sizes under arsenic contamination in the soil – Possible use of new screening tool in ecotoxicology

Collembola can be used as the model organism in the ecotoxicological tests in the soil environment. Currently, two standard bioassays are available (reproduction test in soil and avoidance behaviour test), which are highly sensitive to soil contamination. However, both of those tests have some limitations. Therefore, based on our preliminary research, we propose the alternative test of growth inhibition of springtails as a screening tool to assess the risk related to soil contamination. In this study, the growth inhibition of Collembola species Folsomia candida was analyzed as a response to soil contamination with arsenic: As(III) and As(V). Thus, twenty, 12-day-old juveniles of Collembola, were exposed to 8 concentrations of As in soils, in 6 replicates. The experiment was conducted at two soil pHs (natural and reduced). The endpoint of the test was the reduction in collembolan body size compared to the control soil, measured for all the survivors. More precisely, the feature on which this test is based in the length of the springtail body measured from the beginning of the antennae to the end of the abdomen. It was found that Collembola decrease their body sizes under soil contamination with As. Lower toxicity was found for As(V) in comparison to As(III). For As(V) the decrease in soil pH slightly increased the toxicity effect on Collembola. The effect of growth inhibition significantly correlates with the mortality and reproduction inhibition of Collembola. To conclude, this method can be applied in testing the toxicity of As in the soil as an alternative to the standard methods. However, it needs further investigations considering the exposure time and comparison to the standard methods.