Hair mercury levels in students of Yaroslavl Medical State University (Central Russia)

Objective . To determine the concentration of mercury in the hair of students at Yaroslavl State Medical University (YSMU), Ministry of Health of the Russian Federation. Materials and methods . Between September 2023 and January 2024, mercury levels in the hair of 171 YSMU students aged 17 to 24 years were analyzed. Sample collection was performed in accordance with World Health Organization (WHO) recommendations from the occipital region of the head. Total mercury concentration was determined using atomic absorption spectrometry (AAS) with a RA-915M mercury analyzer equipped with a PYRO-915+ pyrolysis attachment. The students completed questionnaires detailing their age, region of residence, fish consumption frequency, and smoking status. Body mass index (BMI) was calculated based on height and weight measurements. Non-parametric statistical methods (Mann-Whitney U test, Kruskal-Wallis test, and Spearman's rank correlation) were used for data analysis, with a significance level set at p < 0.05. Results . The mean mercury concentration in hair was 0.138±0.013 mg/kg (range: 0.001–1,398 mg/kg). No statistically significant differences were found based on sex, region of residence, or smoking status. It was established that students consuming fish 1–2 times per month had significantly higher mercury levels (0.160±0.020 mg/kg) compared to those who consumed it less frequently (0.112±0.017 mg/kg). The highest concentrations were recorded in individuals with mixed consumption of both marine and freshwater fish (0.179±0.038 mg/kg). An increased accumulation of mercury was noted in individuals with obesity (0.244±0.114 mg/kg). Conclusions . The average mercury level in the hair of YSMU students corresponds to the background values for Central Russia. The primary factor determining mercury accumulation is the frequency and type of fish consumption. Sex, region of residence, smoking, and BMI did not show a statistically significant effect; however, a tendency toward increased metal accumulation was observed in individuals with obesity.