Behavioral response of earthworms to the presence of various copper salts and copper formulations in soil

Copper formulations and copper salts are the most frequently used plant protection agents. Therefore copper concentrations in agriculture soils can easily exceed limit emission value for copper (60 mg Cu/kg for the dry soil), which migh already affect the behavior and consequently the ecological function of soil organisms. Data from literature show that different copper formulations and different salts have different impact on animals. The aim of our study was to find out which copper formulations or copper salts have the greatest impact on the avoidance behavior of earthworms. Avoidance behaviour was studied by the rapid avoidance test on earthworms Eisenia Andrei (ISO 17512-1). We estimated EC50 values for different copper furmulations and salts used. In the study two kinds of copper salts (CuCl2*2H2O and CuSO4*5H2O) and three most frequently applied cooper formulations in Slovenia were used (Cuprablau Z, Cuprablau Z Ultra and Champion). Salts have high solubility, while copper formulations have low solubility and create suspension. To increase water solubility and for better effect of active substance copper formulations usually contain different additives. We found out that avoidance behaviour is more prominent in the soil with copper salts than in the soil with copper formulations, among which differences were also found. The range of copper formulations and salts sorted from the lowest to highest calculated EC50 values is: CuCl2*2H2O < CuSO4*5H2O < Champion < Cuprablau Z Ultra < Cuprablau Z