| BackgroundTens of millions of residents’ health around the world are threatened by the chromium pollution. In early 1990s, hexavalent chromium chronically inhaled in workplace was recognized as a human carcinogenesis, but the relationship between environmental ingestion exposure and cancers has not yet been confirmed. Health effects of the residents from hexavalent chromium pollution are still unclear.ObjectiveTo investigate the health effects of chromium pollution on the general population.MethodsA cross-sectional study was conducted in 2010-2011 in polluted villages and non-polluted villages near an alloy plant located in the outskirts of Jinzhou, Liaoning province. Concentration of chromium in well water and agricultural soil was determined. Permanent residents aged 18 years or above living in local for a long time without occupational chromium exposure were sampled as study population. A questionnaire-based survey about residents’ health status was applied to investigate the health outcomes that were potentially related with chromium pollution. The residents’ blood and urine samples were collected and tested to quantify the chromium-related biomarkers.Mortality information of the entire local population without occupational chromium exposure from 2004 to 2011 was retrospectively collected. Age-specific cancer mortalities of the nationwide rural population during the same period were also used as a national reference (obtained from the National Disease Surveillance System of China). So that to investigate the association between chromium pollution and cancers.Results1. The detection results in the villages Jinchangbao and Nuer River showed that well water was polluted most by hexavalent chromium. In Jinchangbao village, the median of hexavalent chromium concentrations in well water was 1.46 mg/L, and the concentrations ranged from<0.004 to 13.93 mg/L. In Nuer River village, the median concentration was 0.51 mg/L and the concentrations ranged from 0.19 mg/L to 4.78 mg/L. None of the well water samples in Huashan and Chenjiagou village had detectable hexavalent chromium.2. In total,2473 permanent residents aged 18 years or above without occupational chromium exposure were randomly selected to participate in the questionnaire-based survey. The higher the pollution level, the higher the prevalence of digestive symptoms, respiratory symptom and dermatitis was (Ptrend<0.05).3. Four hundred and ninety-six permanent residents aged 18 years or above without occupational chromium exposure were randomly selected to have blood and urine tested. White blood cells, red blood cells, platelets, liver function, renal function and blood glucose and lipid were significantly different between residents of polluted villages and non-polluted villages.4. Totally,53,582 person-years in the polluted villages and 12,108 person-years in the non-polluted villages were followed-up. Mortality for all cancers in the polluted villages was much higher than that in the non-polluted villages [mortality rate ratio (MRR)=9.24; 95% confidence interval (CI):3.42-24.96]. Compared with the nationwide rural population, the MRRs for the polluted villages were 1.53 (95% CI:1.30-1.81) for all cancers,3.76 (95% CI:1.69-8.37) for colorectal cancer, 12.30 (95% CI:4.61-32.77) for pancreatic cancer, and 2.74 (95% CI:2.08-3.62) for lung cancer, respectively. Furthermore, mortalities of liver cancer in men (MRR=1.88; 95%CI: 1.20-2.95) and of stomach cancer (MRR=2.78; 95%CI:1.39-5.56) and breast cancer (MRR=8.67; 95%CI:4.34-17.35) in women were also higher compared to the national reference.Compared to the nationwide rural population, the average age of death of the residents in the polluted villages was 5.22 and 9 years less for all cancer and for lung cancer, respectively.Conclusion Hexavalent chromium pollution may have adverse effects on human health. It could cause residents’abnormal blood indices, hampered renal function, digestive symptoms, respiratory symptoms and dermatitis. It is also associated with increased mortalities of several cancers. |
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