Résumé
Objective:To study the effect of water improvement on urinary arsenic methylation metabolism in population exposed to arsenic through drinking water.Methods:A cluster sampling method was used to select drinking water type arsenism areas in Bayannur City, Inner Mongolia Autonomous Region. Permanent residents lived in the arsenism areas for more than 10 years were selected as the survey subjects. Urine samples ( n = 874, 111, 145) were collected in 2004 (before water improvement), 2014 (4 years after water improvement) and 2017 (7 years after water improvement), respectively, and some subjects were followed up in 2014 and 2017. High performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was used to detect different forms of arsenic metabolites in urine [inorganic arsenic (iAs), monomethylarsonic acid (MMA), dimethylarsenic acid (DMA)], and total arsenic (tAs), the iAs percentage (iAs%), MMA percentage (MMA%), DMA percentage (DMA%), monomethylation rate (PMI), dimethylation rate (SMI), and the ratio of MMA to DMA (MMA/DMA) were calculated. The content and distribution of urinary arsenic metabolites in people exposed to arsenic before and after water improvement were compared and analyzed. Results:Compared with 2004, the levels of iAs, MMA, DMA, tAs and iAs% in urine of arsenic exposed population in 2014 were lower ( Z =-14.12,-12.79,-14.27,-14.21,-6.90, P < 0.001), the levels of MMA%, DMA% and PMI were higher ( Z =-3.22,-2.91,-6.90, P < 0.05); in the same drinking water arsenic exposed population, compared with 2004, the levels of iAs, MMA, DMA, tAs and iAs% in urine ( n = 48) were lower ( Z =-5.57,-5.53,-5.54,-5.55,-2.86, P < 0.05) in 2014, and PMI level was higher ( Z =-2.86, P = 0.004). Compared with 2014, the levels of iAs% and MMA/DMA in urine of arsenic exposed population in 2017 were lower ( Z =-4.97,-2.25, P < 0.05), the levels of MMA, DMA, tAs, DMA%, PMI and SMI were higher ( Z =-4.01,-5.39,-4.77,-4.61,-4.97,-2.25, P < 0.05); in the same drinking water arsenic exposed population, compared with 2014, the level of iAs% in urine ( n = 28) was lower ( Z =-2.87, P = 0.004) in 2017, the levels of DMA% and PMI were higher ( Z =-2.32,-2.87, P < 0.05). Conclusion:Water improvement could significantly reduce the levels of urinary arsenic metabolites iAs, MMA, DMA and tAs and increase the level of DMA% in arsenic exposed population.
Résumé
Objective To investigate skin manifestations and comorbidities of chronic arsenicosis due to conta?minated drinking water, and to explore their possible risk factors. Methods Data about demographic characteristics, skin manifestations and comorbidities were collected from 95 patients with chronic arsenicosis due to contaminated drinking water in Inner Mongolia, and retrospectively analyzed. A logistic regression model was established to analyze associations of skin manifestations and comorbidities with patients′ gender, age, age at onset of drinking of arsenic?contaminated water, arsenic concentrations in water and duration of arsenic exposure. Results Among the 95 patients, 77 had hyperpigmentation, 75 hypopigmentation, 93 palmoplantar keratoderma, 27 skin cancer, and 8 multiple skin cancer. Five patients were complicated by tuberculosis, 15 by hypertension, 2 by rheumatoid arthritis, 4 by cerebral infarction, 7 by coronary heart diseases, 3 by internal malignancy, 6 by hepatic cirrhosis and 2 by anemia. Logistic regression analysis revealed a significant correlation between hyperpigmentation and arsenic concentrations in water(OR=0.32, 95%CI=0.10-0.98;ORadjusted=0.27, 95%CI=0.08-0.90), between occurrence of hepatic cirrhosis and arsenic concentrations in water (OR=24.67, 95%CI=2.69-226.57;ORadjusted=22.51, 95%CI=2.38-213.11), and between occurrence of coronary heart diseases and duration of arsenic exposure(OR=6.41, 95%CI=1.09-37.88;ORadjusted=8.55, 95%CI=1.21-60.41). Conclusions There is a high incidence of aberrant pigment metabolism, palmoplantar keratoderma and skin cancer in patients with chronic arsenicosis due to contaminated drinking water. Different arsenic concentrations in water and duration of arsenic exposure seem to have different influences on the human body.