Heavy metal contamination and health risk assessment in grains and grain-based processed food in Arequipa region of Peru

Heavy metals (HMs) in crops and processed foods are a concern and pose a potential serious health hazard. This study investigated possible presence of HMs in grains and processed products in the Region of Arequipa in Peru. Concentrations of Cd, As, Sn, Pb, and Hg were determined for commonly consumed grains in 18 districts of the region and processed products from 3 popular markets of Arequipa city, using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Cold Vapor Atomic Absorption Spectroscopy (CVAAS). HM concentrations above the Codex General Standard limits were found for As (0.17 mg kg⁻¹) and Cd (0.11 mg kg⁻¹) in cereal grains. Elevated Pb concentrations of 0.55, 0.75, and 5.08 mg kg⁻¹ were found for quinoa, maize, and rice products, respectively; and attributed to processing conditions. The Total Hazard Index (HI) for polished rice and rice products had values between 1 and 10, showing non-carcinogenic adverse effects. Total Target Cancer Risk (TR_T) and uncertainty analysis of percentile P_90% for polished rice and quinoa products gave values above permissible limit of 10⁻⁴, indicating an unacceptable cancer risk. The Nemerow Composite Pollution Index method (NCPI) showed that processed products had a significant pollution level due to the presence of Pb. While most crops grains had acceptable low HM levels, this is the first report of concerning HM concentrations in some consumed grains and processed products in southern Peru and indicates the necessity to find ways to decrease certain toxic metals in foods.