Downward migration of mercury in an old orchard sandy soil

Organic mercury fungicides were applied to apple trees for many years for controlling fungus-borne diseases of the fruit such as scab. It was of interest to study the magnitude of residues of mercury remaining in such orchard soils long after fungicide use ended and possible downward migration of mercury. Soils were collected at increasing depths down to 12 inches from 4 apple orchards in Ontario, Canada that had received annual application of mercury fungicides at least 65 years ago. Analysis of the samples showed that total mercury concentration diminished in a linear fashion with increasing sampling depth.