Assessment of toxicity of heavy metal contaminated soils for Collembola in the field and laboratory

We present a field and laboratory investigation of effects of increasing levels of heavy metal contamination on the biodiversity and performance of collembolans. A 40 year old pollution with Cu, Zn, Pb and Cd pollution due to Cu smelting over 40 years was investigated in a paddy field area of Zhejiang province, Fuyang county. We addressed the questions: 1) how do different collembolan life-forms respond to heavy metals in long-time pollution field site. 2) Are laboratory toxicity testing of field collected polluted soil predictable for the population effects observed in aged heavy metal pollutions.Effects of the heavy metals in the soil from the paddy fields were assessed for growth, survival and reproduction under laboratory conditions. For the tests we used two soil arthropod species: the parthenogenetic, Folsomia candida Willem 1902, and the sexually reproducing, Sinella curviseta Brook 1882, both found at the field study sites. Soil samples were collected along a pollution gradient created with distance from smelters and used for lab testing and to quantify collembolan population abundances and diversity.Collembola from the fields were sorted into sensitive, indifferent and tolerant species to heavy metals according to their response. We present field and laboratory EC10 and EC50–estimates and discuss the problem of identifying cause and effects in the field compared to the laboratory. The single species tests showed that the LC50, EC50 and EC10 values for survival, reproduction and growth of F. candida were 1560, 135 and 68 mg Cu kg-1, respectively, and for S. curviseta they were 3089, 174 and 880 mg Cu kg-1, respectively. Thus, F. candida was more sensitive than S. curviseta. For F. candida we found an agreement between field and lab toxicity, while S. curviseta was less sensitive in the field.