Urinary porphyrins in patients with endemic chronic arsenic poisoning caused by burning coal in China

Objective  To evaluate the effect of arsenic (As) on the porphyrin biosynthetic pathway, urine samples from patients with endemic chronic arsenic poisoning were examined. Subjects and Methods  The subjects were 16 patients, who had been exposed to As from burning coal for 8 to 25 years, and 16 controls living in the same region in Guizhou Province in southwest China. Concentrations of urinary As, porphyrins and ALA were determined by induced coupled plasma mass spectrometry (ICP-MS), high performance liquid chromatography (HPLC) with a reversed-phase column and fluorescence detector, and colorimetric spectrophotometry, respectively. Results  Concentrations of As in patients and controls, 184.40±200.04 and 86.82±64.20μ g/g creatinine (mean ±SD) respectively, were significantly different (p<0.05). The concentrations of various kinds of urinary porphyrins, including isomers I and III of coproporphyrin and pentacarboxylporphyrin, were determined. Positive correlations were observed between As and porphyrins (e.g. total porphyrins, hexacarboxylporphyrin and coproporphyrin III) or between As and ALA in male and female patients. However, porphyrin and ALA concentrations were not significantly different between the patients and the controls. Urinary porphyrin concentrations in females were higher than those in males. Conclusion  Exposure to As from burning coal may influence porphyrin biosynthesis.