Diehloro benzidine

No studies were located regarding cancer efFeets in animals after inhalation exposure to 3,3 -diehloro-benzidine. However, cancer effects have been observed in animal studies where 3,3 -dichlorobenzidine was administered orally or by other routes. See Seetions 2.2.2.8 and 2.5 for further information. 

No aeute-duration oral MRL was ealeulated for 3,3 -diehlorobenzidine because the available studies did not identify appropriate NOAELs or LOAELs (Ashby and Mohammed 1988 Bimer et al. 1990 Cihak and Vontorkova 1987 Ghosal and Iba 1990). No intermediate-duration oral MRL was calculated for 3,3 -dichlorobenzidine beeause the available studies did not identify relevant noncancer effects (Ito et al. 1983 Osanai 1976 Pliss 1959, 1963). No ehronie-duration oral MRL was ealeulated for 3,3 -diehloro-benzidine because there were no NOAELs identified below the lowest available serious LOAEL for convulsions and slight neuronal degeneration in dogs (Stula et al. 1978). 

Death. No deaths were reported in humans from inhalation, oral, or dermal exposure to 3,3 -diehloro-benzidine. In animals, 3,3 -dichlorobenzidine eaused no deaths in rats exposed by the inhalation route in eoneentrations as high as 23,700 mg/m for 2 hours per day for 7 days (Gerarde and Gerarde 1974). In addition, the estimated aeute oral LDjg for rats (7,070 mg/kg for the free base and 3,820 mg/kg for the dihydroehloride salt) and the minimum dermal lethal dose for male and female New Zealand albino rabbits (>8,000 mg/kg) for 3,3 -diehlorobenzidine suggested that the lethal toxieity of 3,3 -dichlorobenzidine is minimal (Gerarde and Gerarde 1974). Consequently, it is unlikely that death will oeeur in humans exposed to 3,3 -diehlorobenzidine at the levels at whieh it oeeurs at hazardous waste sites. 

Gastrointestinal Effects. Gastrointestinal upset was one of the symptoms reported by employees who worked with 3,3 -diehlorobenzidine dihydroehloride (dihydro salt of 3,3 -diehlorobenzidine) (Gerarde and Gerarde 1974). However, there is no eonelusive evidence that 3,3 -dichlorobenzidine eaused these gastrointestinal upsets since there was exposure to other chemieals as well. In addition, 3,3 -diehloro-benzidine has not been found to eause any of these effects in experimental animals. Therefore, it is unlikely that exposure to 3,3 -diehlorobenzidine at hazardous waste sites will cause gastrointestinal effeets in humans. 

Dichlorobenzidine was not deteeted in the ambient air at production facilities at deteetion limits of 0.1-5.0 ng/m (Narang et al. 1982 Riggin et al. 1983). The median concentration of 3,3 -diehloro-benzidine in waste effluents (<10 ppb), groundwater (<10 ppb), surface water (<10 ppb), and soils (<1 ppb) is very low, although significant contamination may be associated with hazardous waste sites (Staples et al. 1985). Moreover, the production and use of 3,3 -diehlorobenzidine-based dyes has decreased to zero over the last 30 years, while environmental and health regulations have been implemented to reduce the release of 3,3 -dichlorobenzidine to the environment. 

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