Influence of copper-based fungicides application on copper contamination of soils of cocoa farm at Akim Tafo, Eastern Region, Ghana

摘要

Copper-based fungicides are used in Ghana to manage black pod disease of cocoa caused by Phytophthora palmivora and P. megakarya. When these fungicides are applied, some drift off into the soil and plants. The gradual accumulation of these copper-based fungicides over a period of time can result in copper contamination of the soil. The extent of copper contamination on fungicide field trial plots at the Cocoa Research Institute of Ghana (CRIG), Akim Tafo was investigated for the dry and wet seasons.Copper contamination in the topsoil (0-5 cm depth) in the dry season ranged from 10.30 ± 0.023 to 21.90 ± 0.026 mgkg"1 whereas the subsoil (5-10 cm depth) contained copper levels ranging from not detected to 15.50 ± 0.021 mgkg1. For the wet season, the ranges for topsoil and subsoil copper concentration were 14.90 ± 0.016 mgkg1 to 27.50 ± 0.003 mgkg"1 and from not detected to 9.20 ± 0.039 mgkg"1 respectively. The calculated geoaccumulation index (Igeo) and Contamination Factor (CF) at the different depths of the soil showed that the soils were in the category of uncontaminated to low contamination at the time of sampling of the farm which had been in existence for less than 15 years.