DETERMINATION OF HEAVY METALS IN RICE CULTIVATED FROM DIFFERENT AREAS IN PART OF NORTHERN NIGERIA

This study was conducted to determine the concentrations of two toxic heavy metals lead (Pb) and mercury (Hg) in rice cultivated from selected areas of northern Nigeria, including Mubi (Adamawa State), Chinno (Kaduna State), Zabarmari (Borno State), and Tudun Wada (Kano State). The samples were collected from the Baga Road Market in Maiduguri and analyzed using LaMotte Smart Spectrophotometer according to standard procedures for heavy metal determination. Results showed that lead concentrations in the rice samples ranged from 0.10 to 1.00 mg/kg, while mercury concentrations ranged from 0.75 to 2.25 mg/kg. The WHO/FAO permissible limits for lead and mercury in food crops are 0.2 mg/kg and 0.67 mg/kg, respectively. Lead levels exceeded the permissible limit in Mubi, while mercury levels were above the safe limit in all the samples, with Zabarmari recording the highest mercury concentration (2.25 mg/kg). These findings indicate that rice from Mubi and Zabarmari may pose higher health risks to consumers. The study concludes that heavy metal contamination in rice cultivated in northern Nigeria is influenced by environmental and anthropogenic factors such as soil composition, irrigation water quality, and proximity to industrial or waste disposal sites. Continuous monitoring, environmental regulation, and awareness among farmers are recommended to minimize contamination and safeguard food safety. Keywords: Heavy metals, Rice, Lead (Pb), Mercury (Hg), Northern Nigeria, Food safety.