Investigation of heavy metal content and health risks of wheat grown in areas near highways in Erzincan province

In this study, the variation of heavy metal concentrations—including aluminum, arsenic, chromium, manganese, cobalt, nickel, copper, iron, zinc, and silver—in bread wheat (Triticum aestivum) samples collected from different locations along the Erzincan–Erzurum highway near the Erzincan Organized Industrial Zone was investigated in relation to distance from the roadway. Potential human health risks associated with wheat consumption were also assessed, considering contributions from traffic emissions, industrial activities, and agricultural practices. It was determined that the concentrations of various heavy metals, including arsenic (0.0289–0.0117 µg kg⁻¹), chromium (0.250–0.078 µg kg⁻¹), aluminum (20.19–3.66 µg kg⁻¹), cobalt (0.120–0.046 µg kg⁻¹), manganese (53.19–18.16 µg kg⁻¹), nickel (3.10–1.40 µg kg⁻¹), copper (6.30–2.73 µg kg⁻¹), iron (56.47–32.79 µg kg⁻¹), zinc (39.01–26.98 µg kg⁻¹), and silver (0.00317–0.00028 µg kg⁻¹) showed a decreasing trend with increasing distance from the highway. However, the calculated Hazard Index (HI) exceeding unity indicates that the overall health risk arises from the combined effects of multiple metal exposures rather than from a single element. In terms of Target Hazard Quotient (THQ), manganese (THQ=1.779) and cobalt (THQ=1.746) having values above 1 emerging as dominant contributors to the elevated HI values. Although the THQ values of the remaining metals were below unity, their cumulative effects contributed to the overall increase in HI. Consequently, while the wheat produced in the study area cannot be classified as acutely hazardous, the findings highlight the necessity of monitoring potential health risks associated with long-term consumption.