Two Nigerian herbal eye cleansers raise arsenic and cadmium concerns
A laboratory study of two herbal eye cleansers bought at a Nigerian market found arsenic and cadmium that raised concerns in exposure calculations. Antioxidant activity appeared in the same preparations, without demonstrating a benefit for eye disease. The single study assessed chemical composition and modelled risk, rather than following patients or representing the entire market.
Science··Evening
Chemical activity came with contamination
Two herbal preparations sold for cleansing eyes contained arsenic and cadmium that raised safety concerns. They were bought in Nigeria’s Enugu State, at Ogbete Market. In the single peer-reviewed laboratory study, arsenic dominated the modelled health-risk burden. Mercury was not detected, and copper and lead fell within the comparison limits used. Those results describe different elements in the same preparations: acceptable findings for some metals do not remove the concerns associated with the others. The calculations estimated exposure-related hazards rather than counting illness among users.[1]
An antioxidant assay measures a laboratory reaction
The researchers used chemical screening, gas chromatography–mass spectrometry and atomic absorption spectrometry to characterise the products. A separate antioxidant assay measured radical scavenging. One preparation reached 96.8 per cent at 100 micrograms per millilitre, while the other plateaued around 50.1 per cent. Those measurements were made in a laboratory reaction, with ascorbic acid as a comparison. They do not measure repair of ocular tissue, improved vision or recovery from an infection, and do not demonstrate clinical efficacy.[1]
Two products cannot describe an entire market
The analysis documented product information and tested samples in triplicate, using calibration and contamination controls. Some compounds in the second preparation were discussed as possible manufacturing or packaging contaminants, without establishing their precise origin. The market sample remains narrow. No patient follow-up or clinical dose-safety study was conducted, so modelled cancer risk should not be reported as an observed cancer rate. The evidence identifies a quality-control concern in the sampled products while leaving the prevalence of contamination across Nigeria unresolved.[1]
