Determination of pesticides residue content in watermelon fruit from Ghana

Abstract

Though watermelon has several benefits, pesticide residues resulting from pesticide application in recent times, appear to have over shadowed the good side of watermelon. The study looked at pesticide residue levels of watermelon grown in Ghana. Materials and methods – Pesticides in watermelon from seven locations in Ghana (Nsadwir, Ayensudo, Cape Coast, Sekondi-Takoradi, Kumasi, Accra and Bolgatanga) were analyzed. A total of 200 watermelon fruits were collected. Pesticides were extracted from 10.0 g of the fruit using a multi-residue extracting method for non-fatty food crops (Essumang et al., 2013). Clean-up was done using a 10 mm chromatographic column with a 1:1 solvent mixture of cyclohexane and dichloromethane, and the samples were analyzed using Varian CP – 3800 series equipped with the 63Ni selective Electron capture detector (ECD)and a Pulsed Flame-Photometric Detector (PFPD). Results and discussion – Fifty-six percent of the samples were found to contain pesticide residue contents above the MRLs. Of these, 39% were organochlorine (OC) and 17% being organophosphate (OP). The levels of the organophosphate (OP) pesticides in the watermelon fruit ranged from 0.9 to 4,383.2 µg kg-1 whereas that of the organochlorine (OC) ranged between 0.7–34.5 µg kg-1 as well as the synthetic pyrethroids pesticides in the range of 0.1–6.4 µg kg-1. Conclusion – In general, some of the pesticides residues in the watermelon fruit had mean levels higher than the maximum residue limits (MRLs) set by the WHO/ FAO. With these high levels, it is likely that consumers may also suffer some accumulation with its attendant health effects due to some of these pesticides. In view of the high pesticides (OC and OP) levels determined, the Ghana Standards Authority and the Ministry of Food and Agriculture must collaborate to probe for other pesticide options that would boost profits of watermelon growers and as well reduce the health and environmental risks frequently associated with pesticides application. The Ghana Standards Authority must again ensure strict application of laws that regulate pesticides influx into the country