Accumulation of copper, lead and arsenic in some Australian orchard soils

A survey was made of copper, lead and arsenic in 98 surface soils from orchards in South Australia and Tasmania and the distribution of these elements in six representative soil profiles was studied. Copper, lead and arsenic have accumulated in the soils due to the use of sprays. Concentrations were found which were 25-35 times greater than background values. Investigation of the profiles indicated that copper and lead have been strongly retained in the upper parts of the profiles, but arsenic can be lost. Possible mechanisms for loss of arsenic are discussed. Copper and lead extracted by DTPA and EDTA were highly correlated with 'total' concentrations determined on aqua regia digests. No relationships were evident between the concentrations of copper, lead and arsenic in former orchard soils and the concentrations in ryegrass and white clover.