Contamination of soils and the coffee plant by copper based fungicides in Kilimanjaro region;Northern Tanzania

Abstract

Residues of copper were determined in a total of 697 samples of soils, coffee leaves, coffee husks, coffee beans and coffee barks in selected districts of Kilimaniaro Region where copper-based fungicides are heavily used Results obtained show that the top soils (0-15 cm) were heavily polluted by copper, one to two thirds of them having more than 100 ppm of copper. Most of the middle soils (16-30 cm) had copper concentrations ranging from 21 to 100 ppm, while most bottom soils (31-45 cm) had copper levels below 20 ppm. Con trol soil samples had a maximum of 2 ppm copper. The concentration of copper in most coffee leaves was also more than 100 ppm. About halfof the husks samples had 21-SO ppm copper. Most coffee berry samples had minimum copper; less than 20 ppm, thus meeting the acceptable Maximum Residue Limit (MRL) of less than 20 ppm copper for coffee beans in most countries. As the top soils and parts of the coffee plant seem to bioaccumulate copper, there is a need to regulate the use 0 copper based fungicides in this region