Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in airborne fine particulate matter and inhalation risk assessment for local residents of Shenzhen, South of China

Objectives To explore the levels and congener profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs) in airborne fine particulate matter(PM2.5) in Shenzhen, South of China. Methods A total of twelve samples... [ view full abstract ]

Objectives To explore the levels and congener profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs) in airborne fine particulate matter(PM2.5) in Shenzhen, South of China.
Methods A total of twelve samples were collected using the high volume air samplers in six sampling sites in respective winter and spring phase and summer and autumn phase. Referring to the US EPA TO-9A for dioxins detection methods, the concentrations of the l7 PCDD/Fs in airborne fine particulate matter were determined by HRGC/HRMS.
Results The total concentrations of PCDD/Fs ranged from 0.32 to 9.35 pg/m3,with an average of 2.45 pg/m3. The toxicity equivalent (TEQ) concentrations ranged from 0.006 to 0.388 pg I-TEQ/m3 ,with an average of 0.095 pg I-TEQ/m3.The four abundant congeners were found to be OCDD(36.49%), 1,2,3,4,6,7,8-HpCDF(14.89%), OCDF(13.34%)and 1,2,3,4,6,7,8-HpCDD(10.92%). 2,3,4,7,8-PeCDF was the dominant contributor to toxicity equivalent, accounting for 34.7%. Positive relationship was found between the levels of fine particle-bound PCDD/Fs and PM2.5 concentration (rs = 0.794，p = 0.006, whereas no correlation was observed for temperature, humidity and atmospheric pressure. Inhalation exposure to PCDD/Fs in airborne fine particulate matter (PM2.5) were 0.023 pg I-TEQ/(kg/d) and 0.035 pg I-TEQ/(kg/d) for adult and children during winter and spring respectively, and the values were relatively higher than those of 0.014 pg I-TEQ /kg/d for adult and 0.021 pg I-TEQ/kg/d for children during summer and autumn, respectively.
Conclusion The levels of PCDD/Fs in airborne fine particle-bound samples collected in Shenzhen were largely lower than the limit published data in the world.