[Studies on the mechanism of Cr-induced DNA damage in glouse].

OBJECTIVE: To investigate the mechanism of Cr-induced DNA damage in glouse. METHODS: The studies were conducted at three pH values(pH 6.5, 7.5, 8.5) with a range of sugars, including D-glucose, alpha-methyl-D-glucose, 2-deoxy-D-glucose, and D-glucose-C-d7. DNA damage was analyzed by gel electrophoresis, and the new species and their lifetime were detected by EPR. RESULTS: The results of these experiments have reinforced the postulate that Cr (V) complexes are likely to be involved in the genotoxic damage that eventually results in Cr-induced cancers. With an increase in the pH values, the amount of Form II DNA decreased due to the increasing rate of Cr (V) disproportionation and H concentration. On the other hand, the presence of sugars in the reaction system generated Cr-mixed-ligand complexes, which could also cause DNA cleavage. CONCLUSION: Proposed mechanism of DNA cleavage are presented induced by Cr (V)-mixed-ligand.

Health safety of main water pipe materials supplied in China market.

OBJECTIVE: To assess the health safety of copper, steel and plastic water pipes by field water quality investigations. METHODS: Four consumers were randomly selected for each type of water pipes. Two consumers of every type of the water pipes had used the water pipes for more than 1 year and the other 2 consumers had used the water pipes for less than 3 months. The terminal volume of tap water in copper and steel water pipes should be not less than 0.1 liter, whereas that in plastic water pipes should be not less than 1 liter. RESULTS: The mean values of the experimental results in the second field water quality investigation of the copper and steel water pipes met the Sanitary Standards for Drinking Water Quality. The items of water sample of the plastic water pipes met the requirements of the Sanitary Standards for Drinking Water Quality. CONCLUSION: Copper, steel, and plastic pipes can be used as drinking water pipes.