Airborne PCB patterns and urban scale in the Southern Río de la Plata Basin, Argentina.

Atmospheric Polychlorinated Biphenyls (PCBs: ∑ 42 congeners) collected by polyurethane passive samplers (PAS-PUFs) in 29 stations from July 2010 to February 2014 (n=141) in the most productive and populated Southern Rio de la Plata area in Argentina were evaluated to assess concentration gradients, potential sources and compositional profiles related to different land use and urbanization. On a global scale, total airborne PCBs concentrations are low/very low (below detection limit to 937pgm-3) and show a significant potential correlation with urban scale increasing 2.5 times each 10 times increase of population reflecting the primary role of urbanization controlling PCB emissions. Compositional patterns evaluated by principal component analysis (PCA) of individual congeners indicated that highly populated atmospheres are enriched in lighter, more volatile tri, tetra and penta chlorine congeners of lighter Aroclor mixtures (from 1242 to 1254) suggesting actual emission of fresh PCBs signatures from sealants, combustion and/or electrical equipment. Sub urban and rural sites show a gradual transition to heavier Aroclor mixtures (from 1254 to 1260) with predominance of more persistent hexa and hepta PCBs indicating an aged background signal resulting from long range transport and/or re-emission from historic reservoirs such as soils.

Massive airborne Endosulfan inputs related to intensive agriculture in Argentina's Pampa.

In order to evaluate the impact of intensive agriculture on air quality in the most productive and populated Argentina's Pampas, a comprehensive assessment of airborne Endosulfan (∑Endo) was performed using polyurethane passive samplers deployed from 2010 to 2013 covering the critical period of Endosulfan restrictions at twenty nine sites in the Rural Pampa and Great Buenos Aires Metropolitan Area (GBA: Horticultural and Urban subareas). ∑Endo concentrations were very high and variable (0.01-63 ng m(-3)), exceeding worldwide reported maxima at Horticultural GBA and Rural Pampa with lowest values at Urban GBA (geometric means: 3.1, 1.1 and 0.53 ng m(-3), respectively). The composition was relatively fresh with strong predominance of Endo I (72 ± 18%) over Endo II (23 ± 15%) and Endo SO4 (5 ± 10%). Airborne ∑Endo was significantly correlated to annual soybean crop in Rural Pampa. ∑Endo concentrations showed a temporal pattern defined by consistent peaks enriched in Endo I during summer application periods, cold temperature minima with higher proportions of Endo SO4 and a general exponentially declining trend over time related to incipient control policies.