User:Envirmod/sandbox

GREAT-ER (Geo-referenced Regional environmental Exposure Assessment Tool for European Rivers) is a model for environmental risk assessment and management of chemicals in river basins.



Description

The GREAT-ER model is an environmental exposure assessment model for chemical substances in river basins. It was first released in 1999 by the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC). The model is implemented as part of a software system that combines a Geographic Information System (GIS) with fate models to produce a simple and clear visualisation of predicted chemical concentrations and water quality along a river.

Applications

GREAT-ER was developed to study the impact of chemicals emitted into rivers by calculating GIS-based equivalents of the Predicted Environmental Concentrations 'PEClocal' and 'PECregional' for the aquatic environment. The latter are conventionally calculated with the European standard risk assessment model EUSES. GREAT-ER calculates regional and site-specific concentrations of chemicals that are emitted down the drain from wide dispersive consumer use, or from defined point sources such as sewage treatment plants, or industrial production plants into a river. Its use for modelling the exposure of ingredients of detergents, personal care products and pharmaceuticals is in the meantime well described in the professional literature (e.g.   ). Results obtained with GREAT-ER are used, for example, by the chemical industry in the context of the European chemicals risk assessment process (Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH)) and the EU Water Framework Directive (WFD).

GREAT-ER is currently (2012) developed for a variety of European river basins: 5 in the UK (River Aire, Calder, Went, Rother, Exe), 1 in Italy (Lambro), 6 in Germany (Itter, Unter-Main, Main, Rur, Rhine in Northrhine Westfalia, and Elbe), 1 in Belgium (Rupel), 1 in France (Mayenne), 1 in Spain (Llobregat) and 1 in Switzerland (Glatt). The applicability of the model is generic and not limited to European river basins.

Comparison with other modelling approaches

In terms of complexity and data needs GREAT-ER is situated between alternative modelling approaches such as Multimedia fugacity models (e.g. Mackay level III models, EUSES), which require relatively few input data compared to GREAT-ER, and the more complex and data-hungry dynamic river models (e.g. RWQM1 from the International Water Association (IWA)). A difference with GREAT-ER is that the latter uses GIS for spatial visualisation of the results. However, many environmental model developments these days also go into the direction of spatially explicit output. Models conceptually similar to GREAT-ER exist, e.g. the iSTREEM model developed for the USA.

An additional Sediment Module for GREAT-ER was developed at a later stage (2006) in order to not only predict concentrations of chemicals in the water phase, but also in the river sediment phase based on the equilibrium partitioning concept. GREAT-ER can also be linked with the ‘TERRACE’ model which allows to include diffuse emissions to the river via agricultural surface runoff.

Software Developments

The most current version is GREAT-ER 3.0 Desktop (2011), designed for Microsoft Windows XP and 7. The entire system is now based on open source software under the GNU Public Licence. PostgreSQL is used as database.

The GREAT-ER 2.0 Desktop version for Microsoft Windows 2000 and XP, released in 2003, replaced the previous ArcView GIS implementation. It was based on the platform-independent and free GIS data viewer 'THUBAN'. This system required the use of an Oracle Database v.8.1.7. A web-based version with more limited functionality was released at the same time.

The original GREAT-ER 1.0 model was released in 1999. It was designed for use with Microsoft Windows NT 4.0 Operating System, and ESRI ArcView 3.0a, 3.1 or 3.2 GIS Software. It development was an initiative of the Environmental Risk Assessment Steering Committee (ERASM) of the Association Internationale de la Savonnerie, de la Détergence et des produits d'Entretien (AISE) and the Comité Européen des Agents de Surface et de leurs Intermédiaires Organiques (CESIO), in cooperation with the UK Environment Agency, Yorkshire Water and ECETOC.

References