医疗废物焚烧厂周边环境空气中二英浓度分布及其健康风险评估

于2015-2018年冬季（12月-2月）对广东省某医疗废物焚烧厂排放烟气及焚烧设施周边2.5 km范围内6个采样点分别进行了4次烟气和环境空气样品采集，应用高分辨气相色谱/高分辨质谱（HRGC-HRMS）联用技术对二（口恶）英（PCDD/Fs）浓度水平进行监测并对其组成特征进行了分析，运用主成分分析法（PCA）对周边环境空气中二（口恶）英来源进行了初步解析，同时采用VLIER-HUMAAN模型评估其对人体的健康风险.结果表明该医疗废物焚烧厂烟气二（口恶）英毒性当量浓度为0.542~21.300 ng·Nm^-3（以I-TEQ计），排放水平较高；周边环境空气中PCDD/Fs质量浓度和毒性当量浓度变化范围分别为0.682~196.000 pg·m^-3和0.036~17.700 pg·m^-3（以I-TEQ计），周边环境空气中PCDD/Fs浓度明显受到排放源烟气落地点的影响.空气样品中二（口恶）英同族体及异构体分布指纹谱图与该焚烧设施排放烟气类似，空气质量浓度主要贡献单体以OCDD、1，2，3，4，6，7，8-HpCDF、OCDF以及1，2，3，4，6，7，8-HpCDD为主，主要毒性贡献单体为2，3，4，7，8-PeCDF.PCA源解析结论与指纹谱图特征分析结论基本一致，该研究区域中环境空气二（口恶）英主要来源于医疗废物焚烧烟气排放.健康风险评估结果表明，该区域人群呼吸暴露风险总体处于较为安全的水平（0.0032~0.141 pg TEQ·kg^-1·d^-1），部分个体的呼吸暴露贡献率超过了评价限值，应引起重视.

Concentrations distribution of PCDD/Fs and its health risk assessment in ambient air around a medical waste incinerator (MWI)

In the winter periods from 2015 to 2018, flue gas of a medical waste incinerator (MWI) in Guangdong Province and ambient air from six sampling sites around the MWI were collected four times to investigate the concentrations and profiles of PCDD/Fs in the region using HRGC-HRMS technique. The sources of PCDD/Fs in ambient air samples were analyzed using principle component analysis (PCA). In addition, health risks were evaluated for the local residents using VLIER-HUMAAN model. The results showed that the levels of PCDD/Fs in the flue gas were relatively high, with an range of 0.542~21.300 ng·Nm^-3(I-TEQ).The concentrations and TEQ values of PCDD/Fs in the ambient air samples ranged from 0.682 to 196.000 pg·m^-3 and from 0.036 to 17.700 pg·m^-3(I-TEQ), respectively. The concentrations of PCDD/Fs in the ambient air were obviously affected by the location of flue gas emission. The congener and isomer profiles of PCDD/Fs in ambient air samples were similar to those in the flue gas of emission source. OCDD, 1,2,3,4,6,7,8-HpCDF, OCDF, 1,2,3,4,6,7,8-HpCDD dominated PCDD/Fs in ambient air samples and 2,3,4,7,8-PeCDF was the dominant congener contributing to TEQ. The results of PCA were consistent with those of fingerprint analysis. The PCDD/Fs in ambient air was mainly from the flue gas of MWI in the region. The health risk assessment suggested that human exposure to PCDD/Fs via inhalaition for the residents living in the studied area was at a relatively safe level (0.0032~0.141 pg TEQ·kg^-1·d^-1). The contribution rate of respiratory exposure to PCDD/Fs for some individuals exceeded the evaluation standard and deserves more attention.