Urinary porphyrins as biomarkers for arsenic exposure among susceptible populations in Guizhou Province, China

Coal is widely used in PR China. Unfortunately, coal from some areas in Guizhou Province contains elevated levels of arsenic. This has caused arsenicosis in individuals who use arsenic-contaminated coal for the purposes of heating, cooking and drying of food in poorly ventilated dwellings. The population at risk has been estimated to be approximately 200,000 people. Clinical symptoms of arsenicosis may include changes of skin pigmentation, hyperkeratosis of hand and feet, skin cancers, liver damage, persistent cough and chronic bronchitis. We analyzed the porphyrin excretion profile using a HPLC method in urine samples collected from 113 villagers who lived in Xing Ren district, a coal-bome arsenicosis endemic area and from 30 villagers from Xing Yi where arsenicosis is not prevalent. Urinary porphyrins were higher in the arsenic exposed group than those in the control group. The correlation between urinary arsenic and porphyrin concentrations demonstrated the effect of arsenic on heme biosynthesis resulting in increased porphyrin excretion. Both uroporphyrin and coproporphyrin III showed significant increases in the excretion profile of the younger age (< 20 years) arsenic-exposed group, suggesting that porphyrins could be used as early warning biomarkers of chronic arsenic exposure in humans. Greater increases of urinary arsenic and porphyrins in women, children and older age groups who spend much of their time indoors suggest that they might be at a higher risk. Whether elevated porphyrins could predict adverse health effects associated with both cancer and non-cancer end-points in chronically arsenic-exposed populations need further investigation. (c) 2005 Elsevier Inc. All rights reserved.

Arsenic speciation in the urine and hair of individuals exposed to airborne arsenic through coal-burning in Guizhou, PR China

The extent of exposure of residents of Changqing (Guizhou, PR China) to arsenic through coal-burning was investigated. Despite the low coal-arsenic content (56.3 +/- 42.5 mg As kg(-1)) when compared with coals collected at different location and times from the same province, more than 30% of the study subjects have shown symptoms of arsenicosis. Coal, urine, hair, and water samples were collected in mid-September 2001 and analysed for arsenic. The average urinary and hair-arsenic concentrations in the exposed subjects were 71.4 +/- 37.1 mug As g(-1) creatinine (control 41.6 +/- 12.1) and 7.99 +/- 8.16 mg kg(-1), respectively. A positive correlation between the hair and urinary-arsenic concentration (R-2 = 0.601) was found. There was no significant difference between females and males for both urinary and hair-arsenic concentrations. Females were found to have a higher dimethylarsinic acid but lower percentages of inorganic arsenic and monomethylarsonic acid in their urine than males. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.