Comparison of the use of Activated Charcoal and C18 for Extracting Pesticide Residues from River Mada, Nasarawa State, Nigeria

Abstract

This study aimed to compare the efficiency of C18 and Activated Charcoal (AC) for extracting pesticide residues (glyphosate, butachlor, lambda-cyhalothrin, and paraquat dichloride) from river Mada in Nigeria during the rainy and dry seasons. Solid phase columns were packed with 0.1 g of each adsorbent material, and water samples were taken from five different points along the river during each season. Pesticide residues were extracted using the two adsorbents, and elution was done using n-hexane, acetonitrile, and acetone. The eluents were analyzed using UV-visible spectrometry. Glyphosate levels were found to be significantly higher (at P<0.05) during the rainy season than in the dry season for C18 with a residue level of 89.9 ppb and 51.8 ppb respectively. AC extractions followed the same pattern with 73.2 ppb during the rainy season and 26.6 ppb during the dry season. AC extractions for butachlor and lambda-cyhalothrin were higher for the dry season with residue concentrations of 250 ppb and 64.4 ppb respectively. Paraquat dichloride was only found with the C18 adsorbent during the dry season with a concentration of 25.8 ppb. The result showed that adsorbent efficiency was pesticide-dependent and that C18 performed better in most cases except for dry season lambda-cyhalothrin and butachlor. The study also found that the pseudo-control (water sample from a township stream) had significantly lower pesticide residue concentrations than the river Mada samples. It can be concluded that River Mada exhibits pesticide residue contamination, with C18 showing greater adsorption than AC but AC’s affordability allows interchangeability with C18. Further study is needed on pesticide bio-concentration in river organisms and enhancing AC’s pesticide adsorption. The treatment plant should adopt comprehensive purification before supplying Mada River water to Nasarawa state for improved health care.