Benzidine derived azo dyes may be degraded metabolically in the gut or liver in man to free benzidine or monoacetylbenzidine. /Benzidine derived azo dyes/
来源:Hazardous Substances Data Bank (HSDB)
代谢
恒河猴在通过灌胃接受两种不同剂量的Direct Brown 95染料后，尿液中平均排泄出1.25%的联苯胺加上单乙酰联苯胺的联苯胺部分，而纯联苯胺的灌胃则产生了1.45%。
Rhesus monkeys excreted an average of 1.25% benzidine plus monoacetylbenzidine of the benzidine moiety in Direct Brown 95 in the urine after receiving two different doses by gavage, whereas gavage with pure benzidine yielded 1.45%.
Caution is also indicated by preliminary results from the NIOSH field studies showing that humans working with these same dyes /Direct Black 38, Direct Brown 95, and Direct Blue 6/ also excrete higher than expected levels of benzidine in their urine. Both laboratory and field studies indicate that these benzidine derived dyes can be metabolized to benzidine, which is present in the urine of animals and humans.
Environmental and urine samples were collected at six factories where workers were potentially exposed to benzidine based dyes (two benzidine based dye manufacturers, two textile dyeing plants, a leather tanning and dyeing plant and a mill where paper was dyed). Monoacetylbenzidine was detected in the urine of 2/8 workers at one of the dye manufacturing plants at levels of 3 and 7 ppb. At the second factory, 4 workers exposed to average levels of 7.9, 5.2, 11.7 and 17.4 mg total particulate/cu m had corresponding urinary concentrations of 52, 11, 10 and 112 ppb benzidine; 590, 248 and 22 ppb monoacetylbenzidine were detected in urine samples containing 112, 52 and 11 ppb benzidine. Traces of diacetylbenzidine, ortho-tolidine and ortho-dianisidine were also detected. Benzidine was not detected in the urine of workers from the other facilities. Minute levels of impurities in the dyestuffs could not account for the quantity of benzidine and its derivatives that were found in the urine samples.
Classification of carcinogenicity: 1) evidence in humans: inadequate; 2) No data for evidence in animals. Overall summary evaluation of carcinogenic risk to humans is Group 2A: The agent is probably carcinogenic to humans. /From table; Benzidine-based dyes/
Urine cytology surveillance has proved useful in evaluating tumors in dyestuff plant workers. The system consists of two-stage tests: periodic urine cytology, followed by, in suspicious cases, urological examinations.
PRECAUTIONS FOR "CARCINOGENS": Whenever medical surveillance is indicated, in particular when exposure to a carcinogen has occurred, ad hoc decisions should be taken concerning ... /cytogenetic and/or other/ tests that might become useful or mandatory. /Chemical Carcinogens/
An epidemiological study of silk dyers and painters who had multiple exposure to benzidine based and other dyes indicated that those exposures were strongly associated with the occurrence of bladder cancer. /Benzidine based dyes/
A strong association relating human exposure to benzidine based dyes with the subsequent development of bladder tumors was presented after a case control mortality study of 200 bladder cancer patients in Japan. The patients were found to have been predominantly kimono painters and dyers. The kimono painters had a habit of forming a point on their brushes by drawing the brush between their lips, which allowed for ingestion of the dyes. Several other case control mortality studies indicate an increased risk of developing bladder cancer in the textile and leather industries, both large users of direct dyes. However, only a few references have been made concerning benzidine derived dyestuffs. In Russia, a medical study concerning the early detection of bladder tumors among textile dyers using benzidine derived dyes revealed an unusual incidence of bladder lesions, some of which were suggested as being of a precancerous nature. The greatest number of such lesions were found in those workers with the highest potential exposure to these dyes. /Benzidine based dyes/
