Determination of levels of copper in Kamiti river along coffee farms in Kiambu, Kenya

Abstract

Copper‐based fungicides are extensively used in the control of coffee pests and diseases because they are relatively cheap and effective. This practice presents serious environmental implications owing to the toxic nature of copper. We report here an assessment on the effects of the use of copper‐based fungicides on River Kamiti, which flows along coffee growing areas of Kiambu District, Kenya. The levels of copper in the river were determined using flame atomic absorption spectrophotometry (FAAS) and were found to range from 0.3 to 2.38 x 10‐2mgL‐1 . It was observed that high levels of copper coincided with coffee spraying seasons and a high amount rainfall, indicating that these contributed to increased seepage of copper in the river. Active pulping factories on both sides of the geographicalregions were also found to be a source of the same. Statistical analysis on the experimental data of copper levels from the study sites showed that there was no significant difference between the regionsimplying that the sampling sites were not the source of variation. Although there is clear evidence that coffee farming introduces copper into the river, the levels of copper in Kamiti river were found to be within acceptable limits and this would be attributed to dilution effects. However, at specific points, the levels of copper were very high threatening the survival of aquatic animals, thus the use of copper compounds is of environmental concern.