典型工业城市德阳大气多环芳烃的污染特征及致癌风险评估

Pollution characteristics and health risk of atmospheric polycyclic aromatic hydrocarbons in a typical industrial city,Deyang,Sichuan province

目的了解典型工业城市德阳大气多环芳烃(PAHs)的污染特征、主要来源及其健康风险。方法利用聚氨酯泡沫(PUF)被动采样技术,于2020年冬季至2021年秋季,在德阳市不同功能区采集大气PAHs,以气相色谱-三重四级杆质谱检测PUF膜中的16种优控PAHs,以特征比值法识别其主要来源,采用美国EPA推荐的健康风险模型评估人群健康风险。结果德阳市大气中16种PAHs的总质量浓度范围为9.22~68.75 ng/m^(3),平均值为(22.97±20.35)ng/m^(3);各功能区大气中PAHs的浓度分布呈现工业区>乡村区>交通-居民混合区>居民-商业混合区>工业-乡村混合区>居民区的特点;季节变化规律呈现冬季>秋季>春季>夏季的特点;各功能区PAHs构成均以中低苯环为主,3环占比最高(54.06%),其次为4环(38.27%)。PAHs主要来源为燃煤或生物质燃烧及机动车尾气排放。各功能区PAHs经呼吸途径所致成人和儿童的日均暴露剂量(ADD)和终身致癌超额危险度(R)从高到低依次为工业区>交通-居民混合区>工业-乡村混合区>乡村区>居民-商业混合区>居民区,且成人均高于儿童。结论德阳市大气PAHs浓度低于北方工业城市,具有明显的季节变化特征,主要来源为燃煤或生物质燃烧和机动车尾气,终身致癌超额危险度略高于可接受水平。

Objective To understand the pollution characteristics,main sources and health risks of atmospheric polycyclic aromatic hydrocarbons(PAHs)in a typical industrial city,Deyang,Sichuan province.Methods The passive sampling technology of polyurethane foam(PUF)was used to collect atmospheric PAHs in different functional areas of Deyang City from winter 2020 to autumn 2021.Gas chromatography-triple quadrupole mass spectrometry was used to detect 16 kinds of optimal control PAHs in PUF membrane,and the main sources were identified by feature ratio method.The health risk model recommended by the U.S.EPA was used to assess people health risks.Results The mass concentration of 16 PAHs in the atmosphere of Deyang City ranged from 9.22-68.75 ng/m^(3),and the mean value was(22.97±20.35)ng/m^(3).The concentration distribution of PAHs in the atmosphere of each functional area was as follows:industrial area>rural area>traffic-residential area>resident-commercial area>industrial-rural area>residential area.The seasonal variation ranked as winter>autumn>spring>summer.The composition of PAHs in all functional areas was mainly middle and low benzene ring,with 3 ring accounting for the highest proportion(54.06%),followed by 4 ring(38.27%).The main sources of PAHs are coal/biomass combustion and vehicle exhaust emissions.The average daily exposure dose(ADD)and the lifetime excess risk of carcinogenesis(R)caused by PAHs through respiratory pathway in adults and children in all functional areas showed industrial area>traffic-residential area>industrial-rural area>rural area>resident-commercial area>residential area from high to low,and adults were higher than children.Conclusion The concentration of atmospheric PAHs in Deyang City is lower than that of the northern industrial city,and has obvious seasonal variation characteristics,the main sources are coal/biomass combustion and motor vehicle exhaust,the lifetime carcinogenic excess risk is slightly higher than the acceptable level.