Combined effect of water contamination with cobalt and nickel on metabolism of albino (wistar) rats
Cobalt and nickel are essential trace metals in the human diet. They are also major components of the alloys employed in the plate and screw used for connecting bones in orthopedic surgery and in the manufacture of artificial organs (Kocijan et al., 2004). Cobalt is used also as coloring agents for pottery, ceramics, and glass. However, excessive amounts of these transitional metal ions are toxic. For example, cobalt and nickel salts have been reported to induce convulsions (Papp et al., 1987), and to cause DNA strand breaks (Christie and Tummolo, 1989), and to be organ toxic (Xie et al., 1995). Cobalt salts are thought to promote the oxidation of reduced glutathion (Iscan et al., 1994) to produce reduction in the number of hepatic hem proteins such as cytochrom P 450 and to interfere with heme metabolism by accelerating its breakdown and inhibiting its synthesis (Nakamura et al., 1975). In addition numerous authors have studied the impact of nickel on health. It can cause dermatitis to certain persons (Accominoti et al., 1998). Particle of nickel may cause some morphological transformations in numerous cellular systems and chromosomal aberrations (Coen et al., 2001). The salts of nickel as particles of nickel can be allergens and carcinogens in man while forming the oxygenated radicals (Lansdown, 1995). This cytotoxicity was investigated in numerous micro organisms (Wu et al., 1994). Nickel was also found to be responsible on many sexual disorders (Chakroun et al., 2002). Cobalt was found also obviously harmful on the prenatal development of mice, rats and rabbits (Szakmary et al., 2001).The prevention of cadmium toxicity by pretreatment with zinc has been explained on the basis of induction of cadmium thionein (Webb, 1972). Nickel was utilized as preventive effect of cadmium (Tandon et al., 1984) and cadmium as preventive effect against nickel toxicity (Khandelwal and Tandon, 1984).