Study On Pollutiong Characteristic, Source-Sink Relationship And Human Exposure Of PBDEs In Environment Of China

Polybrominated diphenyl ethers(PBDEs), a class of flame retardants widely used in our daily life. As the bioacumulation and toxicity was konwn, commercial Penta-BDE and Octa-BDE were listed as Persistent Organic Pollutants(POPs) under the Stockholm Convention on POPs in 2009. A lot of studies on PBDEs pollution were carried out in the world. In China, Studies about PBDEs always focused on the polluted area in Eastern part, the lack of PBDEs information in Western and Central China makes it difficult to understand distribution, transfer and the fate of PBDEs in national scale. Hence, indoor dust samples, air samples and soil samples at Chinese national scale were collected in this study, and the levels, spatial distribution, soil air exchange and human exposure dose were studied. The results of this study will provide the data support and scientific basis for policies on prevention and control of PBDEs.By setting sampling sites in natinal scale, 81 indoor dust samples, 85 air samples and 89 soil samples were collected. PBDEs in indoor dust and soil, air samples were extracted by ultrasonic and Soxhlet, and cleaned using silica gel column, then PBDEs were determined by GC-MS.PBDEs were found in all indoor dust, air and soil samples, indicating the ubiquitous pollution of PBDEs in the environment of China. PBDEs levels in this study were higher than most of other results abroad. The concentration of PBDEs in eastern part was higher than western part in all the three environmental media. The comparison of PBDEs in different sampling sites investaged that PBDEs concentration was highest in urban, followed by suburb and rural area. The congener profile were similar in all the three environmental media, BDE-209 were the most predominant congener, which accounted for 97.5%, 87.7% and 94.8% in indoor dust, air and soil, respectively, followed by BDE-183, BDE-47 and BDE-99. Principal component analysis(PCA) indicated that Deca-BDEs and Penta-BDEs were the main sources to all the three environmental media.Based on the concentration of PBDEs in air and soil, fugacity ratio(ff) were applied to evaluate the soil air exchange of PBDEs, and Gridded ff of BDE-17 and BDE-28 were established. The result showed that, soil air exchange of PBDEs was from air to soil, and lower brominated congeners such as BDE-17 and BDE-28 was nearly soil air exchange balance, ff decreased with the brominated numbers, and ff of BDE-209 was 4.62×10-9 indicated the stong trend of transmission from air to soil. ff showed positive and significant correlation with temperature, and showed negative and significant correlation with latitude and organic matter in soil. Gridded ff of BDE-17 and BDE-28 were matched well the monitoring data, ff were highest in rural, follwed by suburbs, and lowest in urban. The ff of PBDEs decreased from south to north indicated the difference between different areas in China.Combined with the concentration in indoor dust, air and soil, huma exposure model was used to calculate the daily exposure dose(DED) of PBDEs from different pathways, different sampling sites in different areas, and Monte-Carlo was used to evaluate uncertainty of daily exposure dose from indoor dust. The results showed that, DED via indoor dust was highest for todders, and decreased with the increase of ages for other groups, DED in urban area was higher than rural area, DED were highest in Northe area, and lowest in Middle area. DED through air inhalation decreased with the increase of age in South and Middle of China, DED through air inhalation were lowest in North area, highest in Middle area, DED through urban air inhalation was highest, followed by suburbs air, and rural air was the lowest. DED through soil ingestion decreased with increase of age, and decreased from South to North. DED through urban area ingestion was highest, followed by suburbs area, and rural area was the lowest. Dust ingestion were the main route for human exposure of PBDEs in China.The results of Monte Carlo simulation indicated that PBDEs concentration was the biggest factor for daily exposure dose. In general, human exposure dose of PBDEs in China was much lower than the standard of USEPA indicated the low levels of health risk for human.