Spatially explicit multimedia fate models for pollutants in Europe: State of the art and perspectives

Abstract

Keywords:Spatially explicit fate models GIS Data assimilation Analytical solutions Simplifl catión A review by Hollander et al. (in preparation), discusses the relative potentials, advantages and shortcomings of spatial and non spatial models of chemical fate, highlighting that spatially explicit models may be needed for specific purposes. The present paper revie ws the state of the art in spatially explicit chemical fate and transport modeling in Europe. We summarize the three main approaches currently adopted in spatially explicit modeling, namely (1) múltiple box models, (2) numerical solutions of simultaneous advection-dispersion equations (ADE) in air, soil and water, and (3) the development of meta-models. As all three approaches experience lfmitations, we describe in further detail geographic information system (GlS)-based modeling as an alternative approach allowing a simple, yet spatially explicit description of chemical fate. We review the input data needed, and the options available for their retrieval at the European scale. We also discuss the fmportance of, and lfmitations in model evaluation. We observe that the high uncertainty in chemical emissions and physico-chemical behavior in the environment make realistic simulations difficult to obtain. Therefore we envisage a shift in model use from process simulation to hypothesis testing, in which explaining the discrepancies between observed and computed chemical concentrations in the environment takes fmportance over prediction per se. This shift may take advantage of using simple models in GIS with residual uses of complex models for detailed studies. It also calis for tighter joint interpretation of models and spatially disfributed monitoring datase ts, and more refined spatial representation of environmental drivers such as landscape and climate variables, and better emission estimates. In summary, we conclude that the problem is not "how to compute" (i.e. emphasis on numerical methods, spatial/temporal discretization, quantitative uncertainty and sensitivity analysis...) but "what to compute" (i.e. emphasis on spatial disfribution of emissions, and the depiction of appropriate spatial patterns of environmental drivers).

Occurrence and in-stream attenuation of wastewater-derived pharmaceuticals in Iberian rivers

“…Reliability of these models is however constrained by the high variability in chemical emissions from WWTPs and attenuation in surface waters (Pistocchi et al 2010). On the one hand, chemical emissions from WWTP effluents vary widely because of differences in regional usage of the compounds and efficiency of wastewater treatment (Pal et al 2010).…”

Development and validation of a simulation method, PeCHREM, for evaluating spatio-temporal concentration changes of paddy herbicides in rivers

“…Therefore, mathematical models to predict pesticide concentrations in surface water or sediments of paddy elds have been developed, 17,[20][21][22][23] some of which focus on the percentage of the applied pesticide found in runoff from paddy elds. 24,25 Several spatially explicit, geographic information system (GIS)-based fate models have been developed to estimate pesticide concentrations in surface water, [26][27][28] but an immense amount of time and effort must be expended to scale up these models to elds nationwide. The model developed by Yachi et al 14 can estimate the regionspecic PECs of paddy pesticides in river water at 350 sites.…”

USEtox fate and ecotoxicity factors for comparative assessment of toxic emissions in life cycle analysis: sensitivity to key chemical properties

“…An important issue is the determination of which level of spatial differentiation is relevant for ecotoxicity, including sensitivity studies on the influence of climate, e.g., testing the influence of temperature on half-lives. This can be investigated by comparing the output of the USEtox model to the output of multimedia models with a high degree of spatial resolution like the MAPPE model (Pistocchi 2008;Pistocchi et al 2010) or the model developed by Jolliet and coworkers for investigation of human exposure to POPS (Humbert et al 2009;Jolliet et al 2008).…”