TOXICOLOGICAL PROFILE FOR CHROMIUM - Davidborowski.com

CHROMIUM 1522. HEALTH EFFECTS51 Chromium was detected in the urine of guinea pigs after radiolabeled sodium chromate(VI) orchromium(III) trichloride solutions were placed over skin depots that were monitored by scintillationcounting to determine the dermal absorption (Wahlberg and Skog 1965).2.3.4.4 Other Routes of ExposureElevated levels of chromium in blood, serum, urine, and other tissues and organs have been observed inpatients with cobalt-chromium knee and hip arthroplasts (Michel et al. 1987; Sunderman et al. 1989).Whether corrosion or wear of the implant can release chromium (or other metal components) into thesystemic circulation depends on the nature of the device. In one study, the mean postoperative blood andurine levels of chromium of nine patients with total hip replacements made from a cast cobalt-chromiummolybdenumalloy were 3.9 and 6.2 µg/L, respectively, compared with preoperative blood and urinelevels of 1.4 and 0.4 µg/L, respectively. High blood and urinary levels of chromium persisted whenmeasured at intervals over a year or more after surgery. These data suggest significant wear or corrosionof the metal components. No significant difference was found for patients with hip replacements madefrom the alloy and articulated with polyethylene (Coleman et al. 1973). Similarly, serum and urinarylevels of chromium in patients with implants made from a porous coated cobalt chromium alloy withpolyethylene components (to prevent metal-to-metal contact) were not significantly different frompatients with implants made without chromium (Sunderman et al. 1989).A number of factors have been shown to alter the rate of excretion of chromium in humans. Intravenousinjection of calcium EDTA resulted in a rapid increase in the urinary excretion of chromium in metalworkers (Sata et al. 1998). Both acute and chronic exercises have been shown to increase chromiumexcretion in the urine, though the increased excretion did not appear to be accompanied with decreasedlevels of total native chromium (Rubin et al. 1998). An increased rate of chromium excretion has beenreported in women in the first 26 weeks of pregnancy (Morris et al. 1995b). Chromium supplementationdid not appear to alter the rate of excretion into breast milk in postpartum women (Mohamedshah et al.1998).The urinary excretion of chromium after a single or during repeated subcutaneous injections of potassiumdichromate was followed in rats. Following a single dose of 5.35 mg chromium(VI)/kg, chromium wasexcreted rapidly in two phases and was essentially complete at 48 hours. The filtered chromium load roseconsiderably during the first few hours after dosing and exceeded the tubular reabsorption rate. Thisincrease was followed by a decrease that paralleled the urinary excretion of chromium. During repeated