PCDD/Fs, dioxin-like PCBs and PBDEs in air: Preliminary results of the Spanish monitoring program on POPs under the Stockholm convention after four years monitoring

2 . Initial work has focused on POPs monitoring in air based on PAS (Passive Air Sampling) in selected points across the national territory covering remote and urban sites. The program by now is using existing sampling networks in Spain (e.g. EMEP) by means of a very close and successful collaboration with the Spanish Agency of Meteorology (AEMET). The implemented monitoring program intends to become a long-term and stable program analyzing the occurrence of POPs in air and soil samples as well as seeking to expand into other environmental matrices. Polyurethane foam (PUF) disks as passive air samplers allow for semi-quantitative evaluation of atmospheric POP levels. Some advantages like their low cost and easy manipulation explain their common use today in air monitoring studies 3 . Since 2008 and following the recommendations of the Global Monitoring Plan (GMP), Spain implemented a permanent program of air monitoring based on PAS. In this study, air levels of PCDD/Fs, dioxin-like PCBs and PBDEs during the first four years of monitoring (2008-2012) in urban and rural locations throughout the Spanish national territory are presented. Material and Methods Sampling PUF disks (14 cm diameter, 1.35 cm thick) were first pre-cleaned by Soxhlet extraction with solvents of high purity. To avoid contamination, they were transported in glass containers and assembled in stainless steel domed chambers at the sampling sites. Six remote/rural locations and four urban sites were chosen as sampling points. At each sampling point, four PUFs were deployed and collected every 3 months around each season's change. After collection, three of them were pooled and used for PCDD/Fs and dioxin-like PCBs determination. The fourth one was used for PBDE analysis. Analytical Procedure Samples were Soxhlet extracted during 24 h with petroleum ether. Further cleanup was performed by using acidic and basic silica gel multilayer columns. The analysis of all the 17 2,3,7,8-substituted PCDD/Fs and dioxin-like PCBs was performed by gas chromatography coupled to high resolution mass spectrometry (HRGC- HRMS) on a Trace GC ultra gas chromatograph (Thermo Fisher Scientific, Milan, Italy) coupled to a high resolution mass spectrometer (DFS, Thermo Fisher Scientific, Bremen, Germany). Positive electron ionization