Toxicity evaluation of petroleum blending streams: Reproductive and developmental effects of light catalytic reformed naphtha distillate in rats

A distillate of light catalytic reformed naphtha (CAS number 64741-63-5, LC RN-D) administered by inhalation was rested for reproductive and developmen tal toxicity in Sprague-Dawley rats, following a modified OECD Guideline 42 1, Reproductive/Developmental Toxicity Screening protocol. LCRN-D was admin istered as a vapor, 6 h/d, 7 d/ irk at target concentrations of 0, 750, 250 0 or 7500 ppm to female rats for approximately 6 wk from 2 wk prior to mati ng, during mating through gestational d 19, and to males beginning 2 wk pri or to mating for approximately 7 consecutive weeks. Dams and litters were s acrificed on postnatal d 4 and males were sacrificed within the week after the last litter was necropsied. Parental systemic effects observed at the 7 500 ppm expo sure level included slightly lower body weights for males thro ughout the study. Increased kidney to body weight and increased liver to bo dy weight ratio in male rats exposed to 7500 ppm LCRN-D may be related to s lightly lower final mean body weights. Body and organ weight data for femal e rats in all exposure groups were comparable to controls. No test-material -related microscopic changes were observed in the reproductive organs or na sal turbinate tissue of either sex. Reproductive performance was unaffected by exposure to LCRN-D. The mating and fertility indices were 100% in all g roups. There were no significant exposure-related differences in implantati on sites or live pups per litter, and no gross abnormalities were observed in pups from treated dams. Pups born from LCRN-D-exposed dams showed compar able body weights and weight gain to control pups. The viability index on p ostpartum d 4 was greater than or equal to 97%. Under conditions of this st udy, the no-observed-adverse-effect level (NOAEL) for exposure to light cat alytic reformed naphtha distillate for parental effects was 2500 ppm and th e NOAEL for reproductive and developmental toxicity was 7500 ppm.