The Study Of Exposure To Cr⁶⁺ In Drinking Water About Human Health Hazards And Oxidative Stress Damages

Objective: To learn the densities of hexavalent chromium in drinking water from a county in southern Ningxia and analyze the human health hazards and oxidative stress damages, in order to provide a clues for evaluating the exposure levels and health effects of the exposed population.Methods: To extract three water points as the overweight group which from the hexavalent chromium(Cr6+) densities were exceeded in 12 drinking water monitoring points in recent years; and to extract two water points as the control group which from Cr6+ densities were not exceeded and next to the overweight group.Then extracted 60 villages as survey objects from every points of drinking water. Meanwhile, we collected a water sample to test Cr6+ densities from the 5 drinking water points in each wet and dry seasons. Besides, every villages in overweight and control groups were detected by an internal medicine, urinalysis and blood analysis, urinary chromium level, liver and kidney function, as well as oxidative stress damages of peripheral blood.Results: 1.Situation of Cr6+ external exposure in drinking water: the average densities of Cr6+ in drinking water was 2. 82? 3. 22 times in exposure areas.It was higher than the Chinese national standards. 2.The Survey Results: there were no significant difference between the two groups in terms of age, drinking age, sex ratio, education level and have tea or not(P>0.05); there are significant differences between the two groups in terms of nation, smoking or not, drinking or not and per capita annual income(P<0.05). 3.Exposure levels within the drinking crowd: Urinary chromium level in overweight group was(4.34±25.43)μg/L, which was much higher than the control group(P<0.01). 4.Healthy results: The incidences of the nasal mucosal erosion, mucosal perforation, skin itching, scaring, swelling and ulceration in the symptoms and signs checks in overweight group were higher than the control group. The prevalence of Chrome rhinopathy, contacting dermatitis and skin ulcers respectively in overweight group were 4.9%, 4.3% and 4.3%. The values of MCH、PLT、PCT in overweight group were higher than the control group. However, the values of RDW-CV、LYMPH in overweight group were lower than the control group(P<0.05). The positive rates of glucose,bilirubin and nitrite of urine routine testing in overweight group were higher than the control group(P<0.05). The values of serum ALT, CRE and β2-MG in overweight group were higher than that in the control group(P<0.01). 5.Oxidative Stress Results: the activities of GSH-PX and GST in overweight group were significantly increased(P<0.01).However, the activity of CAT in overweight group was lower than the control group(P<0.01).The values of MDA and SOD were not significantly differences between the two groups(P>0.05).Conclusion: 1. The average densities of Cr6+ in drinking water exceeded the Chinese national standard in exposure areas, it is recommended to speed up the local drinking water improvement efforts. 2. The accumulations of urinary chromium will be increase the incidences of nasal chromium, chromium contact dermatitis and others skin diseases. 3. Long-term exposure to excessive Cr6+(2.82 to 3.22 times higher than the standard) in drinking water might cause a mild damage for the abnormal rate of blood and urinalysis analysis. 4.Long-term exposure to excessive Cr6+(2.82 to 3.22 times higher than the standard) in drinking water might bring about lipid hepatic and renal function. 5. By means of the activities of GSH-PX and GST were significantly increased in overweight group, while the activity of CAT was lower than the control group,we may draw the conclusion that exposing to Cr6+ in drinking water can cause the body to produce oxidative stress. 6. As the GSH-PX, CAT and GST activities were significantly more sensitive to reflect the oxidative damage in the body, then the results of present study indicated the possibility that the GSH-PX, CAT and GST providing a basis for evaluating the health effects of exposure to Cr6+ in drinking water. 7. It was more sensitive for the male and the Han autonomy than others,which exposed to Cr6+ in drinking water for oxidative stress damages.