Pine needles are employed as alternative biomonitoring agents in atmospheric studies. In this study, pine (Pinus Pinea) components (needles and branches) and air samples were collected simultaneously to monitor polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) from Gemlik, Turkey between January and December 2016. The relationship between ambient air and pine needles were examined to enlighten the usability of pine components as passive samplers for persistent organic pollutants (POPs) in the Marmara region. Average ∑14PAH concentrations for the ambient air, pine needles, and pine branches were 23.1 ± 18.3 ng/m3, 626 ± 306 ng/g DW and 548 ± 261 ng/g DW respectively. PCB concentrations were 118 ± 74 pg/m3, 7.5 ± 2.1 ng/g DW and 6.8 ± 2.9 ng/g DW and ∑10 OCP concentrations were 122 ± 89 ng/m3,1.3 ± 1.5 ng/g DW and 10.0 ± 3.8 ng/g DW in the same order. Levels of PAHs and PCBs were higher in needles than branches. PAH, PCB and OCP concentrations in pine components tended to decrease with increasing temperatures in spring. PAH compounds with medium and light molecular weighted ones were found to be dominant. On the other hand, the predominant PCB components were the medium-weighted congeners while γ-HCH, Heptachlor endo. Epox. Iso A, endrin aldehyde, and methoxychlor were the dominant OCP species.

The application of biochar in remediation and recovery of heavy metals and/or organic contaminants in water and soil is increasing. However, the adverse effect of biochar to aquatic organisms has not received enough attention. In this study, we conducted a study on the biotoxicity of biochar pyrolyzed from pine needle under oxygen-limited conditions. The toxicity of biochar was expressed with the following endpoints: cell growth, chlorophyll-a (Chl-a), reactive oxygen species (ROS), superoxide dismutase (SOD) content of Scenedesmus obliquus (S. obliquus) and the luminescence of Photobacterium phosphoreum (P. phosphoreum). Here, the effect of free radicals (FRs) contained in biochar was stressed. Our results show that the toxicity of biochar is significantly correlated with the concentration of FRs in biochar particles. Meanwhile, we found the FRs-containing biochar could induce the production of acellular ROS (such as ·OH) in water, which would also induce the production of interior cellular ROS in aquatic organisms. Our findings provide a new insight into the mechanism of toxicity aroused by biochar applications and aid in understanding its potential ecological risk.

Tree canopies play a key role in the cycling of polycyclic aromatic hydrocarbons (PAHs) in terrestrial ecosystems, as leaves can capture PAHs from the air. In this study, accumulation of PAHs was compared in an evergreen species, P. pinaster, and in a deciduous species, Q. robur, in relation to some physio-morphological characteristics. For this purpose, pine needles and oak leaves collected from different sites across Galicia (NW Spain) were analysed to determine PAH contents, specific leaf area, stomatal density and conductance.Leaves and needles contained similar total amounts of PAHs. The major contribution of particle-bound PAHs in oak (the concentrations of 4- and 5-ring PAHs were two times higher, and those of 6-ring PAHs five times higher in oak than in pine) may be related to the higher specific leaf area (13 and 4 cm2 g−1 dry mass in respectively oak and pine). However, the major contribution of vapor-phase PAHs in pines may be affected by the stomatal conductance (two times higher in pine than in oak). Moreover, an increase in the diameter at breast height of trees led to an increase in accumulation of PAHs, with pine capturing higher amounts of low and medium molecular weight PAHs. The study findings underline the potential role of trees in improving air quality, taking into account the canopy biomass and life cycle.

We evaluated spatial patterns of mercury (Hg) deposition through analysis of foliage and forest floor samples from 45 sites across Adirondack Park, NY. Species-specific differences in foliar Hg were evident with the lowest concentrations found in first-year conifer needles and highest concentrations found in black cherry (Prunus serotina). For foliage and forest floor samples, latitude and longitude were negatively correlated with Hg concentrations, likely because of proximity to emission sources, while elevation was positively correlated with Hg concentrations. Elemental analysis showed moderately strong, positive correlations between Hg and nitrogen concentrations. The spatial pattern of Hg deposition across the Adirondacks is similar to patterns of other contaminants that originate largely from combustion sources such as nitrogen and sulfur. The results of this study suggest foliage can be used to assess spatial patterns of Hg deposition in small regions or areas of varied topography where current Hg deposition models are too coarse to predict deposition accurately.

Short chain chlorinated paraffins (SCCPs) have been of considerable concern in recent years due to their high production volumes, environmental persistency and potential for long range atmospheric transport. Vegetation can take up considerable amounts of semivolatile organic compounds from the atmosphere and can act as indicators of local contamination. Paired pine needles and bark were sampled around Beijing during winter and summertime to investigate the distribution of SCCPs in urban areas. Levels in bark samples ranged 5.79–37.5 μg/g on a lipid normalized basis (lw) with a geometric mean (GM) of 16.9 μg/g lw whereas levels were 3.03–40.8 (GM 11.8) μg/g lw for needles. Average congener group abundance profiles showed equal contribution of all four carbon groups (C10–13) in wintertime whereas higher abundances of C10 and C11 groups were found during summer. Uptake of SCCPs occurred mainly via kinetically limited gaseous deposition and particle bound deposition in the investigated area.

Biochar plays an important role in the behaviors of organic pollutants in the soil environment. The role of humic acid (HA) and metal cations on the adsorption affinity of polychlorinated biphenyls (PCBs) to the biochars in an aqueous medium and an extracted solution from a PCBs-contaminated soil was studied using batch experiments. Biochars were produced with pine needles and wheat straw at 350 °C and 550 °C under anaerobic condition. The results showed that the biochars had high adsorption affinity for PCBs. Pine needle chars adsorbed less nonplanar PCBs than planar ones due to dispersive interactions and separation. Coexistence of HA and metal cations increased PCBs sorption on the biochars accounted for HA adsorption and cation complexation. The results will aid in a better understanding of biochar sorption mechanism of contaminants in the environment.

To better understand interaction mechanisms of pine needles with persistent organic pollutants, single-solute and bi-solute sorption of phenanthrene and pyrene onto isolated cuticular fractions of pine needle were investigated. The structures of cuticular fractions were characterized by elemental analysis, Fourier transform infrared spectroscopy and solid-state 13C NMR. Polymeric lipids (cutin and cutan) exhibited notably higher sorption capabilities than the soluble lipids (waxes), while cellulose showed little affinity with sorbates. With the coexistence of the amorphous cellulose, the sorption of cutan (aromatic core) was completely inhibited, so the cutin components (nonpolar aliphatic moieties) dominated the sorption of bulk needle cuticle. By the consumption of the amorphous cellulose under acid hydrolysis, sorption capacities of the de-sugared fractions were dramatically enhanced, which controlled by the exposed aromatic cores and the aliphatic moieties. Furthermore, the de-sugared fractions demonstrated nonlinear and competitive sorption due to the specific interaction between aromatic cores and polycyclic aromatic hydrocarbon.

The aim of this study was to validate lichens as biomonitors of PAH atmospheric deposition; for that, an inter-comparison between the PAH profile and concentrations intercepted in lichens with those of air, soil and pine needles was performed. The study was conducted in a petro-industrial area and the results showed that PAH profiles in lichens were similar to those of the air and pine needles, but completely different from those of soils. Lichens accumulated higher PAH concentrations when compared to the other environmental compartments and its concentrations were significantly and linearly correlated with concentrations of PAHs in soil; we showed that a translation of the lichen PAHs concentrations into regulatory standards is possible, fulfilling one of the most important requirements of using lichens as biomonitors. With lichens we were then able to characterize the air PAHs profile of urban, petro-industrial and background areas. Lichen PAH concentrations can identify geographic areas that may be out of compliance with regulatory standards.

We evaluated foliar and forest floor chemistry across a gradient of N deposition in the Northeast at 11 red spruce (Picea rubens Sarg.) sites in 1987/1988 and foliar and forest floor chemistry and basal area growth at six paired spruce and deciduous sites in 1999. The six red spruce plots were a subset of the original 1987/1988 spruce sites. In 1999, we observed a significant correlation between mean growing season temperature and red spruce basal area growth. Red spruce and deciduous foliar %N correlated significantly with N deposition. Although N deposition has not changed significantly from 1987/1988 to 1999, net nitrification potential decreased significantly at Whiteface. This decrease in net potential nitrification is not consistent with the N saturation hypothesis and suggests that non-N deposition controls, such as climatic factors and immobilization of down dead wood, might have limited N cycling. Data from the 1999 remeasurement of the red spruce forests suggest that N deposition, to some extent, is continuing to influence red spruce across the northeastern US as illustrated by a significant correlation between N deposition and red spruce foliar %N. Our data also suggest that the decrease in forest floor %N and net nitrification potential across sites from 1987 to 1999 may be due to factors other than N deposition, such as climatic factors and N immobilization in fine woody material (<5 cm diameter).

Recent studies have demonstrated that natural abundance 15N can be a useful tool for assessing nitrogen saturation, because as nitrification and nitrate loss increase, δ15N of foliage and soil also increases. We measured foliar δ15N at 11 high-elevation spruce-fir stands along an N deposition gradient in 1987-1988 and at seven paired northern hardwood and spruce-fir stands in 1999. In 1999, foliar δ15N increased from -5.2 to -0.7[per thousand] with increasing N deposition from Maine to NY. Foliar δ15N decreased between 1987-1988 and 1999, while foliar %N increased and foliar C:N decreased at most sites. Foliar δ15N was strongly correlated with N deposition, and was also positively correlated with net nitrification potential and negatively correlated with soil C:N ratio. Although the increase in foliar %N is consistent with a progression towards N saturation, other results of this study suggest that, in 1999, these stands were further from N saturation than in 1987-1988. Foliar δ15N increased with increasing N deposition from Maine to NY, but decreased between 1987-1988 and 1999