Safety assessment of red-colored iron oxide as heavy metal lead pigment substitute in terms of genotoxicity in rat liver tissue

Lead is commonly used in battery, pipe and paint, and its exposure causes harmful effects on humans and animals. Especially, the usage of lead pigment-contained products increases frequency of lead exposure. Recently, to reduce frequency of the lead exposure, substitute for lead pigment were developed and used. However, the safety evaluation of substitute material is barely performed. In this study, we aimed to perform safety assessment of lead pigment substitute, red-colored iron oxide, compare to lead in terms of genotoxicity. To evaluate the safety of red-colored iron oxide, chemicals were orally administrated to rats for 28 days and genotoxic effect on the liver tissues was estimated using comet assay and micronucleus assay which have been recognized as standard genotoxicity testing guideline by Organization for Economic Co-operation and Development. Alkaline comet assay indicates DNA single strand and double strand break whereas micronucleus assay detects chromosomal damage. The result showed that red-colored iron oxide has lower genotoxicity than lead in the liver tissue. Through our study, we suggest that red-colored iron oxide pigment might have more safety than lead pigment and replace lead pigment. Further study assessing safety of red-colored iron oxide in other organs is needed.