上海中心城区道路灰尘中氯代多环芳烃的时空分布特征

Seasonal and spatial distributions of chlorinated PAHs in road dust from downtown Shanghai

选取了上海中心城区的道路灰尘作为研究对象,运用气相色谱-质谱(gas chromatography-mass spectrometry,GC/MS)联用技术对道路灰尘中20种氯代多环芳烃(chlorinated polycyclic aromatic hydrocarbons,Cl PAHs)进行了检测,分析了道路灰尘中Cl PAHs的时空分布特征和毒性当量(toxic equivalent quantity,TEQ)等.结果表明,11种Cl PAHs的检出率均大于50%,说明Cl PAHs在上海中心城区道路灰尘中普遍存在.研究区域内的Cl PAHs浓度呈现出明显的季节特征,即冬季>夏季,冬季ΣCl PAHs浓度最高为24.9 ng/g干重.在空间分布上,交通枢纽区浓度最高(冬季为21.2 ng/g干重,夏季为10.7 ng/g干重),建筑施工区、商业区次之,近绿地区最低.在道路灰尘中最主要的两个组分是6-Cl Ba P和7-Cl Ba A.Cl PAHs在冬季和夏季的TEQ范围分别为0.01～4.81和0.01～1.78 ng-TEQ/g干重,其中7-Cl Ba A在Cl PAHs总毒性当量中的贡献最大.

Concentrations of twenty chlorinated polycyclic aromatic hydrocarbons （C1PAHs） in road dust from downtown Shanghai were analyzed using gas chromatography- mass spectrometry （GC/MS）. Eleven of twenty C1PAH congeners were found in road dust samples with more than a detection rate of 50%, indicating that C1PAHs were ubiquitous in road dust in downtown Shanghai. Seasonal variability of C1PAHs concentrations were observed, with higher concentrations in winter than in summer. The highest concentration of total C1PAHs was 24.9 ng/（g dw） （dw means dry weight） in winter. Concentrations of C1PAHs varied greatly in different functional areas, In particular, the highest concentration was found in transportation hub regions （21.2 ng/（g dw） in winter and 10.7 ng/（g dw） in summer） followed by construction and commercial areas, while the lowest concentration was found in green areas. The compositional analysis showed that 6-C1BaP and 7-C1BaA were the two most important components in the road dust samples. The toxic equivalent quantity （TEQ） ranges of C1PAHs were 0.01～4.81 ng-TEQ/（g dw） in winter and 0.01-,～ 1.78 ng-TEQ/（g dw） in summer, and the toxic equivalent of 7-C1BaA contributed the most.