Heavy Metal Concentrations and Health Risk Assessment of Melon Seeds (Citrullus lanatus) From Selected Markets in Ghana.

Abstract

Melon seeds (Citrullus lanatus (Thunb.) Matsum. & Nakai), locally known as 'agushi' in Ghana, are widely consumed as thickeners in soups and stews and are a valued oilseed crop, yet data on toxic element contamination from the Bono Region remain scarce. This study determined cadmium (Cd), arsenic (As), lead (Pb) and mercury (Hg) concentrations in melon seeds from six market locations across the Bono, Bono East and Ahafo Regions of Ghana, and evaluated health risks for adult males (body weight [BW] = 70 kg), adult females (BW = 60 kg) and children aged 6-12 years (BW = 26 kg); the sex-differentiated assessment reflects the well-established influence of body weight on mass-normalised dietary exposure. Samples were oven-dried, ground and acid-digested using a concentrated HNO3/HClO4 (4:1, v/v) mixture on a programmable hot plate, then analysed by atomic absorption spectrophotometry. Mean concentrations ranged from 0.0017-0.0086 mg/kg (Cd), 0.0013-0.0027 mg/kg (As), 0.00103-0.00108 mg/kg (Pb) and 0.000130-0.000383 mg/kg (Hg), all substantially below EU 2023/915 maximum levels. Hazard indices (HI: 0.0091-0.0202, calculated using the USEPA IRIS 2025 updated RfD for As of 6.0 × 10^-5 mg/kg/day) were well below 1.0, confirming negligible noncarcinogenic risk. Incremental lifetime cancer risk (ILCR) values (1.04 × 10^-6-2.81 × 10^-6) fell within the acceptable range (10^-6-10^-4). Melon seeds from the sampled markets are safe for regular consumption under current exposure conditions.