TOXICOLOGICAL PROFILE FOR CHROMIUM - Davidborowski.com

CHROMIUM 1892. HEALTH EFFECTSand stage-7 spermatids were found in male rats administered sodium dichromate(VI) by gavage for90 days at 20 mg chromium(VI)/kg/day (Chowdhury and Mitra 1995). These effects were not replicatedin potassium dichromate feeding studies conducted by NTP in which rats were exposed to 8.4 mgchromium(VI)/kg/day (NTP 1996b) and mice were exposed to 32.2 mg chromium(VI)/kg/day (NTP1996a). Alterations in sexual behavior, aggressive behavior, and decreases in absolute testes, seminalvesicles, and preputial glands weights were observed in male rats exposed to 42 mg chromium(VI)/kg/dayas potassium dichromate in drinking water (Bataineh et al. 1997). An increase in testes weight wasobserved in mice exposed to 6 mg chromium(VI)/kg/day as potassium dichromate for 12 weeks; at 14 mgchromium(VI)/kg/day, decreases in seminal vesicle and preputial gland weights were also observed(Elbetieha and Al-Hamood 1997). Intraperitoneal injection studies provide supporting evidence that themale reproductive system is a target of chromium(VI) toxicity. Intraperitoneal injections of rabbits with0.7 mg chromium(VI)/kg as potassium dichromate for 6 weeks resulted in morphological changes in thetestes consisting of marked edema of interstitial tissues, congestion of blood vessels, and completeabsence of spermatocytes in the seminiferous tubules (Behari et al. 1978). In rats receivingintraperitoneal injections of 2 or 3 mg chromium(VI)/kg as potassium dichromate for 69 days, a numberof dose-related testicular effects were observed including decreased sperm counts and motility, testiculartubules with disturbed spermatogenesis, decreased late stage spermatids and germ cell numbers at stageVII, and altered testicular enzyme levels (Saxena et al. 1990b). The pathological alterations were notseen after 34 days of exposure. In another study by this group, intraperitoneal injections of 2 mgchromium(VI)/kg/day as potassium dichromate resulted in ultrastructural changes in the testes (leakage ofSertoli cell tight junctions in seminiferous tubules, cytoplasmic vacuolization and degeneration ofmitochondira in the seminferous epithelium, and disruption of mitochondrial sheaths of tail midpieces ofspermatids) (Murthy et al. 1991).In females, a reduction in the number of medium- and large-sized follicles was noted in rats exposed to$60 mg chromium(VI)/kg/day as potassium dichromate in drinking water for 20 days (Murthy et al.1996). At higher concentrations, histological alterations in the ovaries, a decrease in the number ofova/mouse, and an increase in estrus cycle duration were observed. Additionally, delayed vaginalopening and impaired fertility were observed in female mouse offspring exposed to 66 mgchromium(VI)/kg/day as potassium dichromate in drinking water on gestational day 12 through lactationday 20 (Al-Hamood et al. 1998).Mixed results have been found in studies designed to assess the impact of chromium(VI) exposure onfertility. Two multigeneration studies in which rats were exposed to 0.2 mg chromium(VI)/m 3 as sodium