[Distribution of arsenic in surface water in Tibet].

This research was aimed on studying the arsenic distribution of water in Yarlung Zangbo and Singe Zangbo basins in Tibet. Results showed that arsenic concentrations were different in different types of the water. The sequence of arsenic concentration from high to low was hot spring water (4920 microg x L(-1) +/- 1520 microg x L(-1), n =2), salt lake water (2180 microg x L(-1) +/- 3840 microg x L(-1), n =7), well water (194 microg x L(-1), n = 1), freshwater lake water (163 microg x L(-1) +/- 202 microg x L(-1), n =2) and stream water (35.5 microg x L(-1) +/- 57.0 microg x L(-1), n=74). The high arsenic concentration in surface water in Singe Zangbo and the upstream of Yarlung Zangbo were found. The average concentration of arsenic in water from Singe Zangbo (58.4 microg x L(-1) +/- 69.9 microg x L(-1), n = 39) was significantly higher than that from Yarlung Zangbo (10.8 microg x L(-1) +/- 16.9 microg x L(-1), n = 30). Arsenic concentration in 43.2% of stream water samples and all of the hot springs, saline lakes and well water were higher than 10 microg x L(-1). Yarlung Zangbo and Singe Zangbo are important sources of drinking water for the local people. There is a high risk for the local people who may suffer from chronic arsenic poisoning.

[Porphyrins as the early biomarkers for arsenic exposure of human].

To investigate the effects of arsenic exposure on porphyrins excretion profiles in human, porphyrins were measured by HPLC and total arsenic by HG-AAS in urine samples collected from arsenicosis-endemic areas and control sites in Guizhou Province. Analytical data showed that urinary uroporphyrin-III and coproporphyrin-III were significantly elevated in arsenic-exposed group compared with those in control group, while urinary coproporphyrin-I was not significantly higher in arsenic-exposed group than that in control group. Not any significant difference was found in porphyrins between the male and female except for 20-40 years age group. As far as age was concerned, arsenic-exposed group of <20 years showed significant increases in uroporphyrin-III and coproporphyrin-III compared with the control group of <20 years. Similarly, arsenic-exposed groups of 20-40 years and >40 years also showed significant increases in coproporphyrin-III compared with corresponding age groups of control. Besides, there were positive correlations between the urinary arsenic and total coproporphyrin, and total porphyrin. The effects of arsenic exposure were associated with increased porphyrins excretion, which was suggested that porphyrins were possible to be used as biomarkers of early health effect due to arsenicosis.

[Content and distribution of fluorine in Chinese coals].

Nationwide sampling program is designed according to the resources distribution and coal-forming periods as well as coal rank and yield of coal in China, and 305 coal samples were collected from 26 provinces, municipalities and autonomous regions. Fluorine in coal is determined by pyrohydrolysis / fluoride-ion selective electrode method. Fluorine in coals is mainly of an inorganic nature. Coal rank has no effect on fluorine content. The influence of a factor, such as geological age, on fluorine contents might be concealed by other factors, more research should be done to discern it. The distribution of fluorine in each province, municipality and autonomous region's coals is studied, and the fluorine source in coal-burning endemic fluorosis areas should be estimated over again. The contents of fluorine in Chinese coals show logarithm normal distribution, and 90% of values ranged from 47mg/kg to 347mg/kg, the average fluorine content in Chinese coals was designated as the geometric mean, 136mg/kg. Fluorine in Chinese coals is within the world coal's range.