Remedial options for copper-contaminated vineyard soils

Total copper concentrations in some Victorian vineyard soils, due to the use of copper (Cu)-based fungicides, have increased to the point where remedial strategies need to be considered to avoid Cu toxicity. In Australia, the National Environment Protection (Assessment of Site Contamination) Measure recommends that total Cu concentrations in soil exceeding the threshold concentration of 100 mg/kg require environmental investigation. However, it is likely that some Cu-contaminated soils, to be used for horticultural purposes, will need to be remediated even if the total Cu concentration is <100 mg/kg. This paper examines some prospective remedial strategies for Cu-contaminated vineyard soils and demonstrates that, apart from stopping the addition of Cu, in situ remedial strategies are the only practical remedial options for Cu-contaminated vineyard soils. Active mixing, both lateral and vertical, of contaminated surface soil with less contaminated or uncontaminated deeper soil is an in situ and well-suited remedial option for most low and medium Cu-contaminated vineyard soils. The strategy relies on attenuation processes to be more effective. Other ameliorative strategies with potential as remedial options for low and medium Cu-contaminated soils, including phytoremediation and attenuation (liming and addition of organic matter), are also considered.