The Concentration of Potentially Toxic Elements (PTEs) in Salt: A Global Systematic Review, Meta-Analysis, and...

Salt is a food additive that, in addition to essential minerals, can carry potentially toxic elements (PTEs), including heavy metals. This study systematically evaluates heavy metal levels in salt samples collected globally. The studies published from 2000 to 2024 were identified through searches of international databases. The associated human health risks were estimated by calculating the hazard quotient (THQ) and cancer risk (CR) using a Monte Carlo Simulation (MCS) model. The analysis revealed that nickel (Ni) with a concentration of 974 µg/kg had the highest concentration among the studied PTEs, followed by arsenic (As) at 297 µg/kg, mercury (Hg) at 123 µg/kg, lead (Pb) at 81.5 µg/kg, and cadmium (Cd) at 75.9 µg/kg. The highest concentrations of trace elements in salt were found in Jordan (As = 13,000 µg/kg, Ni = 20,000 µg/kg), Tanzania (Cd = 5,620 µg/kg, Pb = 3,540 µg/kg), and Pakistan (Hg = 7,650 µg/kg). Additionally, the concentration of PTEs was higher in sea salt than in rock salt. Consumption of Pakistani salt poses a severe noncarcinogenic risk from mercury (Hg) for both adults and children, with Target Hazard Quotient (THQ) values far exceeding the safety threshold of 1. For As, significant noncarcinogenic risks (THQ > 1) were identified in Jordan, Pakistan, and Malaysia for both adults and children. The carcinogenic risk from As exceeded the acceptable standard (CR > 1 × 10⁻⁴) in Pakistan and Jordan for both demographic groups. These findings underscore the need for immediate policy interventions, including revising national permissible limits for heavy metals in salt, implementing advanced purification methods for salt processing, and establishing continuous monitoring systems throughout the supply chain.