北京市某城区大气PM2.5中苯并[a]芘暴露的人群致癌风险评估

目的 了解北京市某城区采暖季大气PM_2.5中苯并a]芘的污染水平和人群致癌风险。 方法 于2016年12月—2017年2月采集北京市某城区每日PM_2.5样品,采用高效液相色谱—荧光检测器法测定PM_2.5上苯并a]芘浓度,评估不同污染天气过程的污染水平下,男性、女性、总人群因吸入苯并a]芘导致的人群终生超额致癌风险和预期寿命损失。结果 苯并a]芘日均质量浓度中位数为5.20(2.13,11.05)ng/m³。重污染天气过程的苯并a]芘日均质量浓度中位数为12.90(5.76,21.98)ng/m³,是非重污染天气过程3.90(1.13,8.92) ng/m³的3.3倍,差异有统计学意义。北京市某城区男性在重污染天气过程、非重污染天气过程以及研究期间的苯并a]芘暴露浓度下,IUR取值为1.1×10^-6(ng/m³)^-1时,超额致癌风险分别为9.42×10^-6、2.85×10^-6和3.80×10^-6,预期寿命损失分别为55.1、16.7和22.2 min;IUR取值为8.7×10^-5(ng/m³)^-1时,超额致癌风险分别为7.46×10^-4、2.25×10^-4和3.01×10^-4,预期寿命损失分别为4 359、1 318和1 757 min。北京市某城区女性在不同污染天气过程的苯并a]芘浓度暴露下,IUR取值为1.1×10^-6 (ng/m³)^-1及8.7×10^-5(ng/m³)^-1时,超额致癌风险均超出10^-6的可接受水平,预期寿命损失分别为62.0、18.7、25.0 min和4 903、1 482和1 976 min。 结论 基于2016年冬季苯并a]芘浓度数值的健康风险评估结果说明,不同天气过程的苯并a]芘暴露水平对北京市某城区人群具有潜在致癌风险。重污染天气过程苯并a]芘暴露导致的超额致癌风险和预期寿命损失是非重污染天气过程的3.3倍。女性的超额致癌风险略低于男性,但预期寿命损失略高于男性。

Carcinogenic risk assessment of inhabitants exposed to B[a]P in ambient PM2.5 in an urban district of Beijing

Objective To investigate the pollution level of ambient PM_2.5-bound benzo a] pyrene (Ba]P) in the heating season and its carcinogenic risk for inhabitants in an urban district of Beijing. Methods PM_2.5 was daily sampled in an urban district of Beijing from December 2016 to February 2017. High performance liquid chromatography-fluorescent detector (HPLC-FLD) method was used to determine the concentration of PM_2.5-bound Ba]P. We assessed the lifetime excessive cancer risk and life expectancy loss due to inhalation of PM_2.5-bound Ba]P in males, females and the general population based on days with different pollution levels. Results The median value of daily average concentration of PM_2.5-bound Ba]P was 5.20 (2.13, 11.05) ng/m³. The median value of daily average concentration of PM_2.5-bound Ba]P in heavily polluted days was 12.90 (5.76, 21.98) ng/m³, which was 3.3 times that of non-heavily polluted days (3.90 (1.13,8.92) ng/m³), showing a statistically significant difference. When the inhalation unit risk (IUR) was 1.1×10^-6 (ng/m³)^-1, the excessive cancer risks for males due to Ba]P exposure in heavily and non-heavily polluted days and the study period were 9.42×10^-6, 2.85×10^-6 and 3.80×10^-6, respectively, with the life expectancy loss being 55.1, 16.7 and 22.2 minutes, respectively. When the IUR was 8.7×10^-5(ng/m³)^-1, the excessive cancer risks of males were 7.46×10^-4, 2.25×10^-4 and 3.01×10^-4, respectively, with the life expectancy loss being 4,359, 1,318 and 1,757 minutes, respectively. When the IURs were 1.1×10^-6 (ng/m³)^-1 and 8.7×10^-6 (ng/m³)^-1, the excessive cancer risks for females due to different Ba]P exposure levels were all more than the acceptable value of 10^-6, with the life expectancy loss being 62.0, 18.7, and 25.0 minutes as well as 4,903, 1,482 and 1,976 minutes,respectively. Conclusion The Results of health risk assessment based on the Ba]P concentration in the winter of 2016displayed that Ba]P exposure in days with different polluted levels is regarded as potentially carcinogenic ininhabitantsin this urban district of Beijing. The excessive cancer risk and life expectancy loss due to Ba]P exposure in heavily polluted days were 3.3 times those of non-heavily polluted days. The excessive cancer risk for females was slightly lower than that in males, but life expectancy loss was slightly higher than that in males.