Towards more ecologically realistic scenarios of plant uptake modelling for chemicals: PAHs in a small forest

• Published in: The Science of the total environment 2015-02, Vol.505, p.329-337
• Main Authors: Terzaghi, Elisa, Zacchello, Gabriele, Scacchi, Marco, Raspa, Giuseppe, Jones, Kevin C., Cerabolini, Bruno, Di Guardo, Antonio
• Format: Article
• Language: English
• Subjects: Canopies; Corylus; Dynamic; Ecological effects; Ecology; Environmental Monitoring; Environmental risk assessment; Forests; Leaf area index; Leaf traits; Mathematical models; Models, Biological; Multimedia fate models; PAHs; Photosynthesis; Plants; Plants (organisms); Plants - metabolism; Polycyclic Aromatic Hydrocarbons - analysis; Polycyclic Aromatic Hydrocarbons - metabolism; Seasons; Soil Pollutants - analysis; Soil Pollutants - metabolism; Uptakes; Vegetation
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2014.09.108

The importance of plants in the accumulation of organic contaminants from air and soil was recognized to the point that even regulatory predictive approaches now include a vegetation compartment or sub-compartment. However, it has recently been shown that many of such approaches lack ecological realism to properly evaluate the dynamic of air/plant/soil exchange, especially when environmental conditions are subject to sudden variations of meteorological or ecological parameters. This paper focuses on the development of a fully dynamic scenario in which the variability of concentrations of selected chemicals in air and plant leaves was studied weekly and related to the corresponding meteorological and ecological parameters, to the evaluate their influence. To develop scenarios for modelling purposes, two different sampling campaigns were performed to measure temporal variability of: 1) polycyclic aromatic hydrocarbon (PAH) concentrations in air of a clearing and a forest site, as well as in leaves of two broadleaf species and 2) two important leaf and canopy traits, specific leaf area (SLA) and leaf area index (LAI). The aim was to evaluate in detail how the variability of meteorological and ecological parameters (SLA and LAI) can influence the uptake/release of organic contaminants by plants and therefore air concentrations. A principal component analysis demonstrated how both meteorological and ecological parameters jointly influence PAH air concentrations. SLA, LAI, as well as leaf density were showed to change over time and among species and to be directly proportional to leaf/canopy uptake rate. While hazelnut had the higher leaf uptake rate, maple became the most important species when considering the canopy uptake rate due to its higher LAI. Other species specific traits, such as the seasonal variation in production of new leaves and the timing of bud burst, were also shown to influence the uptake rate of PAHs by vegetation. [Display omitted] •PAH air concentrations are affected by meteorological and ecological parameters.•SLA is directly proportional to PAH uptake rate of vegetation.•LAI needs to be split to know the importance of each species in PAH accumulation.•Attention must be paid when collecting deciduous species leaves over time.•A dynamic fate model is required if the data are to be interpreted reliably.