RESUMEN
A simple modeling concept was previously applied to study air-foliage exchange of both polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) using field measurements. In this paper, the predictive capabilities of this framework were tested using an independent set of data collected at the same sampling location for a different time period. Firstly, atmospheric (particle-bound and gaseous phase) PBDE and PAH concentrations were used to predict their accumulation in spruce needles. Conversely, we used PBDE and PAH concentrations in vegetation to predict their atmospheric concentrations. In both cases, calculated and measured values showed good agreement, providing evidence that the developed framework and our derived deposition velocities can be used as a predictive tool for these two different classes of semi-volatile organic compounds.
Asunto(s)
Contaminantes Atmosféricos/análisis , Atmósfera/química , Material Particulado/análisis , Picea/química , Compuestos Orgánicos Volátiles/análisis , Monitoreo del Ambiente/métodos , Predicción/métodos , Éteres Difenilos Halogenados/análisis , Modelos Químicos , Hidrocarburos Policíclicos Aromáticos/análisisRESUMEN
Polybrominated diphenyl ethers (PBDEs) are flame retardants used in a variety of consumables. Models indicate that air-vegetation exchange plays an important role in their global distribution. The present study surveyed PBDEs in spruce needles and air (gaseous and particulate-bound) over an annual cycle to model accumulation of PBDEs in vegetation. Air-particulate distributions revealed that penta and higher BDE congeners were mainly associated with particulates even in warmer temperatures, whereas for the tri- and tetra-BDE congeners, a significant temperature dependence was observed. Using measured vegetation and atmospheric concentrations from bud burst 2004 to June 2005, a modeling concept was developed to determine PBDE deposition velocities to vegetation. Particulate-bound deposition velocity was calculated to be 3.8 m/h. Net gaseous transfer velocities ranged from 2.4 to 62.2 m/h and correlated significantly with log K(OA). These derived values were used to model PBDE accumulation by vegetation through time, and these agreed well with measured values. This study provides the necessary background for modeling PBDE transport between air and coniferous vegetation globally.