Heavy Metal and Micro Elements Distribution Patterns and Inter-element Relationships in Market-sourced Lavender (Lavandula spp.) from Khorasan Razavi Region, Iran

Heavy metal contamination in medicinal plants poses significant health risks, yet comprehensive assessment of metal accumulation patterns in lavender (Lavandula spp.) remains limited. This study analyzed concentrations of Fe, Zn, Cu, Mn, Cd, Pb, and Ni in lavender leaf samples from three major medicinal plant markets in Iran's Khorasan Razavi region to evaluate potential health risks. Seventy-two samples were systematically collected, pooled into 18 composite samples, and analyzed using flame atomic absorption spectrometry following acid digestion. Iron showed the highest variation among markets, with Mashhad samples containing significantly elevated concentrations (971.40 ± 5.9 mg·kg⁻¹) compared to Quchan (480.82 ± 0.95 mg·kg⁻¹) and Kashmar (52.45 ± 1.24 mg·kg⁻¹) (P≤0.01). Principal component analysis revealed two components explaining 90.71% of the total variance, with principal component 1 (PC1) (60.14%) showing strong loadings for essential metals and PC2 (30.57%) characterized by Ni and Pb. Health risk assessment indicated that while individual metal exposures remained below hazardous levels (Target Hazard Quotient <1), cumulative risks were higher in urban markets (Hazard Index: Mashhad 0.264 > Quchan 0.144 > Kashmar 0.082). Strong correlations between essential metals (Fe-Cu: r=0.884, Fe-Zn: r=0.989, P≤0.01) suggest common uptake mechanisms. While current metal concentrations generally pose limited health risks, enhanced accumulation in urban market samples highlights lavender's potential for environmental monitoring and necessitates market-specific quality control measures to ensure consumer safety.