天然石棉引起环境低浓度石棉纤维污染的癌症风险评价

Assessment of the health risk likely to be caused by the environmental exposure to low dose asbestos fibers

利用相差显微镜对大姚县土壤和岩石中青石棉矿物引起的农村大气环境石棉纤维浓度进行分析测定,并利用总癌症、肺癌和间皮瘤分析模型对大气环境石棉污染对当地居民的健康风险进行评价。结果表明,大姚县农村大气石棉纤维平均浓度为0.003 75 f/mL,最大浓度达到0.029 7 f/mL,表明其大气环境已经受到石棉纤维的普遍污染。环境石棉纤维污染的总癌症风险、肺癌风险和间皮瘤风险分别达到86.3×10-5、291.48×10-5和7.1×10-5,表明大姚县农村大气环境石棉纤维污染对当地居民身体健康具有严重的影响。另外,由于当地居民对环境石棉纤维的暴露为终生暴露,因此年龄越大的人群的总癌症风险、肺癌风险和间皮瘤风险越高。

The given paper is aimed at introducing our work on the assessment of health hazard likely to be caused by the environmental exposure to the low-dose asbestos fibers. For our research purpose, we collected 48 air samples in Jan., 2011, from Dayao County, Yun- nan. We have determined the concentrations of asbestos fibers in the air caused by crocidolite mineral in the soft and rock by phase-contract microscopy along with an evaluation of human health risks by using the assessment model for surveying the general cancer, lung cancer and mesothelioma. The results of our evaluation indicate that the mean and maximum concentrations of asbestos fibers in rural air of Dayao were 0.003 75 f/mL and 0.029 7 f/mL, respectively. This indicates that the rural air of Bayao county has been broadly contaminated by the asbestos fibers, mainly derived from crocidolite mineral in the soil and the rock, due to the disturbance of human activities and climatic and meteorological factors. The mean risks of the general cancer, lung cancer and mesothelioma caused by asbestos fibers in the air were 86.3 × 10^-5, 291.48 × 10^-5 and 7.1 × 10^-5, respectively. To be exact, the minimum risk rates of general cancer, lung cancer and mesothelioma were 69 ×10^-5, 267.65 × 10^-5, and 0.57 ×10^-5, while those of maximum liability were 683.1 ×10^-5, 470.99 × 10^-5, and 56 × 10^-5correspondingly. All the facts indicate that the health of local residents has been significantly influenced by asbestos fibers in the air. Actually, they have been suffering such an exposure over years. As a result, the risk-inciuence rates of the above said cancers are usually higher for elderly residents than for young, particularly higher for the seventy-aged people than for the forties. This suggests that the risks of such cancers were significantly influenced by the year-long exposures, which reflects that the incidence of such cancers in Dayao are also remarkably influenced by the asbestos fiber concentrations in the air.