Levels and source regions of polychlorinated biphenyls (PCBs) measured in background air in Leova, Moldova

Polychlorinated biphenyls (PCBs) are persistent, toxic and bio-accumulating industrial chemicals that can undergo long-range atmospheric transport. While production ended in most countries during the 1970s and 1980s, it continued in Eastern Europe until 1993. The Republic of Moldova never produced PCBs, but accumulated large amounts over the years, for the most part as dielectric oil used in electric equipment. Even though efforts have been done in recent years to safely manage and dispose the stockpiles of PCBs in Moldova, data on atmospheric levels of PCBs in this region remain rather limited. However, such data are of vital importance to support monitoring efforts under the European Monitoring and Evaluation Program (EMEP) as well as the Stockholm Convention on POPs. The objectives of this study were (i) to determine ambient concentrations of PCBs and other POPs in air at a background site in Moldova (Leova: 46o29’18’’N, 28o17’0’’E), (ii) to compare and contrast measured levels of PCBs with data from other countries and regions, as well as (iii) to evaluate possible source regions using the Lagrangian particle dispersion model FLEXPART. Weekly 24-hour measurements were collected from September 2009 to October 2010, using a high volume air sampler. Glass-fiber filters and polyurethane foams from the sampler were extracted, analyzed and quantified for PCBs using GC/MS. The FLEXPART-model was used for simulations of atmospheric transport and was run backward in time to identify the source regions of POPs at the sampling site. Here we present concentrations of PCBs and compare our results with data from other EMEP background stations in Europe and additional sites. The more likely source regions affecting the measured levels of PCBs in Leova are finally identified and discussed on the basis of model calculations.