Assessment of heavy metal concentrations and associated health risks in Nigeria-branded and marketed sanitary products using deterministic, multivariate and probabilistic approaches

Abstract

Dermal exposure to heavy metals has emerged as a public health concern, particularly for women of reproductive age who regularly use sanitary pads and related materials for menstrual hygiene. Previous studies have shown that heavy metals and other contaminants present in sanitary products may be absorbed through the vulvar skin and vaginal mucosa during prolonged use. These tissues possess high permeability and absorption capacity, which may facilitate the entry of contaminants into systemic circulation. This study determined the concentrations of selected toxic heavy metals, namely lead (Pb), cadmium (Cd), arsenic (As), and chromium (Cr), in Nigerian-branded sanitary products and evaluated their potential health risks using deterministic, multivariate and probabilistic approaches. Five brands of sanitary pads, together with one brand each of panty liners, cotton wool and tissue paper from different batches, were randomly purchased from retail outlets in Lagos, Abuja and Port Harcourt, Nigeria. Samples were digested using a mixture of HNO₃ and H₂O₂ (5:1, v/v), and the metal concentrations were determined using atomic absorption spectrophotometry. Pb was detected in all sanitary products at concentrations ranging from 10.97 to 19.66 mg kg⁻¹. Cd and As were detected in several samples, with concentrations ranging from 1.31 to 2.10 mg kg⁻¹ and 0.92 to 4.85 mg kg⁻¹, respectively. Cr was present in all products at concentrations between 0.44 and 1.63 mg kg⁻¹. The concentrations of Pb, Cd and As exceeded safety limits established by the World Health Organization and the European Union, whereas Cr remained within permissible limits. Hazard Quotient and Hazard Index estimates indicated potential non-carcinogenic health risks, particularly from Pb and Cd, which contributed to the elevated risk observed for Besense Pad, Diva Pad and Toilet Roll. Multivariate and probabilistic analyses further supported these findings.