Mobility and availability of copper in agricultural soils irrigated from water treated with copper sulfate algaecide

In this paper, downward movement and availability of copper in soils irrigated with CuSO4 algaecide treated water were examined using column leaching experiments. Two simulations considering 1 and 10 years irrigation period were conducted at copper application rate of about 18.7 kg CuSO4/ha/year. Effluent copper concentrations and vertical distribution of acid and DTPA-extractable copper in the soil columns were determined. Nearly 99% of the applied copper was retained in the soil with a C-e/C-0 values on the order of 10(-3). Retention profiles showed that copper was retained in the upper 2 to 3 cm of the soil. However, a significant fraction of the retained copper was detected in available form (DTPA-Cu) suggesting that plants toxicity could be a major limitation for the use of CuSO4 treatment in irrigation water.