Using GIS to Visualize Sources of and Mitigation Options for Priority Pollutants

Geographical Information Systems (GIS) have been proven as useful tools in water management for different spatial analysis. In the ScorePP research project we employ GIS analysis for control and reduction of priority pollutant (PP) sources in urban watersheds. Such GIS requires large amounts of data, which can be of different time and spatial scales, numeric or descriptive, measured or estimated. Integration and harmonization of all the data and information into a common system is a challenging task that was tackled within the ScorePP project (www.scorepp.eu). Specific goals of this research are (1) to propose a data organization in order to be able to integrate it in a general framework for GIS analyses of the PP emissions and (2) to use such a system for visualizations of PP sources and mitigation options.The data that need to be integrated is comprised of: economic and other activities in the watershed, production and other processes in the watershed, geospatial data from the watershed, quantification of the emission sources, data on treatment and mitigation options. Starting point of the integration of these data is unique classification of emissions of PPs. We propose a combined classification, composed of three codes, i.e. each source of PP emission, also called emission string (ES) is uniquely declared by three classification codes (1) CAS registry number; compound or PP number; (2) NOSE-P: (Nomenclature for sources of emissions classification); and (3) NACE (Classification of Economic Activities in the European Community).Since emissions are generated also from the sources that do not have a NACE classification (e.g. some emissions from households), additional grouping of the ES was implemented. Each ES belongs to one or more identified types of emissions. Some examples of the emission strings types are: households, facilities, gardens, railroads, roads. All together we identified 24 emission types.Such data structure integrates economic and other activities as well as production and other processes with PP emissions and enables identification of all potential sources in a watershed. Additional information that is collected and linked to each emission string (in a relational database) is:Compartment to which an ES is released and percentage of the emission that contributes to the specified compartment. Following compartments are taken into account: Air (A), Water direct (WD), Water indirect (WI), Water (W), Urban permeable surface (UP), Urban impermeable surface (UI), Urban surface (U), Ground water (G).Release Pattern indicates the dynamics (e.g. weekly, monthly or yearly) of a PP release from specific process.Release Factor is a specific value (and corresponding units) of an emission. It is introduced as a range of values, i.e. low and high.Finally a database of treatment and mitigation options is linked to the described ES database in order to have information about fate of the PPs in the environment. The proposed structure of the emission data and of the treatment and mitigation options is able to interact with each other and with the watershed specific geographic data to perform different calculations and visualizations of existing emission sources and their mitigation options.There is a variety of questions and queries that can be addressed with the developed database, such as: identification of potential sources of PP emissions for given watershed; visualisation of measured sources of emissions; visualisation of estimated quantities of sources of emissions. Figure 1 presents the emissions of Ni in a hypothetical city. It is evident that the sources are mainly point sources, but also line elements (roads and railroads) are identified as sources of Ni emissions. Additionally the database can be used for implementing different source control options. Within the ScorePP project they were divided into six groups (1) banning a substance, (2) reduction by law, (3) substitution, (4) voluntary reduction, (5) implementation of on-site treatment, and (6) implementation of end of pipe treatment.As the basic queries are already running in the developed framework, future work is aimed at full implementation of PP source control options into the developed GIS relational database. The result will be a decision support system for visualizing (geographically) PP sources, controlling PP sources, and performing treatment and control scenarios in the watershed.