Gastrointestinal tract chronic exposure

Several chronic inhalation and oral studies and acute dermal studies in animals are reported in the literature. These studies exposed several species of animals to both soluble and less-soluble nickel compounds. The target organs were found to be the respiratory system for inhalation exposure and the respiratory system, gastrointestinal tract, hematological system, and kidneys for oral exposure at high levels. Reproductive and developmental effects were observed in animals after inhalation exposure and after oral exposure to nickel. Nickel sensitivity and dermatitis were also observed. 

In a chronic-duration study, groups of 60 male and 60 female Fischer 344 rats were exposed to 0, 0.005, 0.025, or 0.164 ppm HDI over a 2-year period. Control rats were sham-exposed rats (conditioned air exposure). No significant changes in absolute or relative gastrointestinal tract organ weights were found (Mobay Corporation 1989). 

The vapor may irritate the respiratory system and, in high concentrations, have narcotic action. Chronic exposure can lead to loss of sensation in hands and feet. Irritant to skin, eyes, and the gastrointestinal tract. Experimental teratogenic, reproductive effects.3,5,6 TLV-TWA 50 ppm (176 mg/m3).7... 

Gastrointestinal Effects. Information regarding gastrointestinal effects in animals after dermal exposure to CDDs is limited. No histopathological changes were observed in the gastrointestinal tract of Swiss Webster mice chronically exposed to 0.005 g 2,3,7,8-TCDD 3 days per week (NTP 1982a). 

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