Accumulation of Fine Particles Onto Three Coniferous Species

There is concern that airborne contaminants generated by applying sewage sludge to land for agricultural purposes may pose significant health risks to nearby residents. Polybrominated diphenyl ethers (PBDEs) have been shown to be both a persistent class of organic chemicals in sewage sludge and to accumulate in the epicuticular wax of coniferous vegetation. Thus, local coniferous species may passively sample PBDEs and provide information related to the atmospheric dispersion of contaminants associated with land-applied sewage sludge. This work uses a controlled exposure chamber to simultaneously subject three conifer species (loblolly pine, short leaf pine and eastern red cedar) native to central North Carolina to a Rhodamine-6G aerosol, which acts as a surrogate for particle-bound PBDEs. Accumulation as a function of exposure for each species is evaluated. Findings suggest that, to normalize particle accumulation across the three species, a factor of 1.35 should be applied to cedar results reported in ng/g. Additionally, the ratio of projected area to mass is used to explain interspecies variations. This information is useful to studies that employ local vegetation as passive samplers of particle-bound contaminants such as those evaluating community exposures to land-applied sewage sludge