Prenatal Developmental toxicity study in the rat/FeMn slag/OECD 414/oral/GLP
The purpose of this study was an assessment of the influence of FeMn Slag (ferromanganese slag), a by-product of the production of manganese alloys, on embryo-fetal survival and development when administered during the organogenesis and fetal growth phases of pregnancy in the rat. Three groups of 20 females received FeMn Slag at doses of 100, 330 or 1000 mg/kg/day by oral gavage administration, from Day 6 to 19 after mating. A similarly constituted Control group received the vehicle, corn oil, at the same volume dose as treated groups. Animals were killed on Day 20 after mating for reproductive assessment and fetal examination. Clinical observations, body weight and food consumption were recorded. Adult females were examined macroscopically at necropsy on Day 20 after mating and the gravid uterus weight recorded. All fetuses were examined macroscopically at necropsy and subsequently by detailed internal visceral examination or skeletal examination.
There were no unscheduled deaths, no signs associated with dosing, no adverse treatment related clinical signs, effects on body weight or food consumption and no findings detected at necropsy of the dams. All animals receiving FeMn slag were pregnant. There was no effect on embryo-fetal survival growth or development. Slightly high placental weights (up to 111% of control) were recorded, attaining statistical significance at the 330 and 1000 mg/kg/day dose levels, but the magnitude of the difference was considered not to be adverse.
In this study ferromanganese slag was well tolerated and the maternal no observed adverse effect level (NOAEL) was concluded to be 1000 mg/kg/day. There was no adverse effect on embryo-fetal survival, development or growth, therefore the embryo-fetal no observed adverse effect level (NOAEL) was considered to be 1000 mg/kg/day