SECONDARY LEAD INGESTION VIA OCULAR EXPOSURE TO TRADITIONAL SOUTH ASIAN, MIDDLE EASTERN AND NORTH AFRICAN EYE COSMETICS AND IMPLICATIONS FOR IQ IN CHILDREN

With persistent lead poisoning cases reported for many US immigrant children populations along with the recently revised CDC benchmarks for defining lead poisoning there has been an increasing focus on evaluating non-traditional lead exposure pathways for children. Using a market-basket sampling approach and sequential dissolution analysis in simulated tears (lacrimal fluid) this study determined the bioaccessibility of lead from traditional South Asian, Middle Eastern and North African eye cosmetics (kohl, kajal and surma). Of the 26 samples examined, 58% contained lead levels higher than the 0.1 µg/g FDA lead action level for products intended for use by children, with bulk lead concentrations reaching 177,700.0 µg/g. Sequential dissolution analysis over a sixty hour time course (in twelve hour increments) resulted in lead concentrations ranging from 0.025 mg/L to 0.53 mg/L. After 60 hours of exposure, the bioaccessible fraction of lead ranged from 0.00030% to 5.4%.

By combining known nasolacrimal drainage rates with observed dissolved lead concentrations in simulated tears we quantified the amount of lead entering the gastric system. These values were compared with the bilinear model lead-IQ dose response values from the joint World Health Organization and Food and Agriculture Organization (2011) to determine approximate IQ declines associated with chronic cosmetic exposure. X-ray diffraction analysis for the highest lead concentration samples identified galena as the lead bearing phase, therefore the dose response modeling assumed bioavailability to be 25%, based on an EPA report for galena in swine. Modeling results suggest that chronic exposure to lead-contaminated eye cosmetics can result in losses of 0.41 to 12.14 IQ points for children. Secondary ingestion of lead dissolved in lacrimal fluid via nasolacrimal drainage presents a novel and potent exposure pathway for childhood lead poisoning.