Geospatial and Health Risk Modeling of Lead Contamination in Traditional Kohl from Algeria

Traditional kohl cosmetics remain widely used in Algeria for cultural and medicinal purposes, yet their composition often includes lead (Pb), a toxic heavy metal associated with severe neurological and developmental effects. This study provides the first integrated geospatial and quantitative health risk assessment of Pb contamination in kohl products marketed across 15 Algerian cities. Lead concentrations, determined by Flame Atomic Absorption Spectrometry (FAAS), ranged from 1.25 to 326 mg·kg–1, with a mean of 90.4 mg·kg–1 substantially exceeding the international cosmetic safety limit of 20 mg·kg–1. Spatial analysis revealed that lead contamination is primarily concentrated in major northern urban centers (Annaba, Algiers, Tizi-Ouzou), which function as commercial distribution hubs, while southern regions displayed lower and more heterogeneous contamination levels. Hazard Quotient (HQ) modeling was applied for adults, children, and infants under multiple exposure scenarios. Under conservative assumptions (1% absorption, 50 mg·day–1 application), HQ values remained below unity, indicating low immediate dermal risk. However, sensitivity analyses revealed that increased absorption (up to 10%) or higher usage frequency can elevate HQ values near or above 1, particularly for infants and young children, highlighting a potential chronic exposure risk. Correlation and cluster analyses confirmed strong positive associations between Pb concentration and HQ indices (r > 0.95), validating the dose–response behavior of the model and the internal consistency of analytical data. Comparison with regional and international studies shows that Algerian kohl products remain significantly contaminated relative to those from countries with strict regulatory frameworks. The findings emphasize persistent public health vulnerabilities linked to informal markets and insufficient product surveillance. This work demonstrates the value of coupling chemical analytics, spatial statistics, and toxicological modeling to generate actionable evidence for cosmetic safety policy. Strengthened regulatory enforcement, consumer education, and laboratory monitoring are urgently recommended to mitigate lead exposure from traditional cosmetics in Algeria and similar regions.