Prediction of accumulation and leaching of fungicide copper in agricultural soils

Copper is applied extensively to protect a number of crops, including vines/grapes, citrus and other fruits, against fungal attack. In contrast to biodegradable organic chemicals, metals such as copper cannot be degraded in the environment and so can potentially remain as contaminants in the environment for extended periods of time. Metals can undergo processes such as ‘aging’ in certain environmental compartments, such as soils, that reduce their bioavailability and toxicity, but typically a significant proportion of the metal remains in a potentially bioavailable form for extended periods. There is thus a need to assess the potential ecological risks of the ongoing use of copper as a fungicide. This study has been commissioned by the European Copper Task Force (ECTF) to assess the potential risks of the current and future use of copper as a fungicide. Using a set of typical copper application rates, and a set of scenarios covering a representative range of soil types across Europe, we have simulated copper accumulation in soils, surface waters and sediments using an intermediate complexity dynamic model (the IDMM) designed specifically for the long term behaviour of metals. Predicted copper concentrations over time have been compared with Predicted No Effect Concentrations for soil, waters and sediments to assess the current potential risks, and the prospects for the future development of risk under a scenario of continued copper application have been assessed.