Version 2.2; May 2017
For SPADE 3.2
This document describes the technical details, construction and operation of the fully revised multimedia fate model Simplebox 3.0. Former versions of Simplebox have been used for prediction of intermedia concentration ratios in order to harmonisation of environmental quality objectives. Also Simplebox is (partly) built in the "European Union System for the Evaluation of Substances" (EUSES) As an illustration a fully worked out example computation is admitted Simplebox 3.0 is a nested multi-media fate model of the “Mackay type”. The environment is modelled as a set of forty well-mixed, homogeneous compartments (air, fresh water and marine water compartments, sediment, soil and vegetation compartments) on a local., regional, continental and global scale. The global scale represents the Northern Hemisphere and contains a moderate, arctic and tropical zone. The model needs substance properties, emission rates and transformation rate constants as input and computes steady-state concentrations for all boxes as output. Simplebox is a generic model in the sense that it can be customised to represent specific environmental situations. With respect to Simplebox 2.0, several changes have been made. The main modifications are the addition of a local scale nested in the regional scale and refinement of the seawater currents between the regional, continental and moderate zone of the global scale. All parameters are renamed and the lay out of the model has been changed.
This chapter will provide guidance on how to estimate environmental exposure. More specifically, it will deal with: Estimation of the releases to air, water (either wastewater and/or surface water), and soil at local and regional scale.Fate and distribution of the releases in environmental compartments (air, soil, surface water, sediment, biota) and sewage treatment plants. Calculation of exposure concentrations in / doses for, respectively: Environmental compartments (Section R.16.6.1), in terms of Predicted Environmental Concentrations (PECs), at both local and regional scales, covering both direct exposure of organisms and exposure via the food chain for predators. Man via the environment (Section R.16.6.8) in terms of human daily intake of the substance through drinking water, fish, leaf crops, root crops, meat and dairy products, at local and regional scale. Most of the current guidance on environmental exposure estimation has been developed mainly for organic substances. Metals and metal compounds present particularities (natural background and historical releases, speciation, adsorption/desorption behaviour, differences in bioavailability) which require specific adaptations when performing the exposure assessment. These issues are considered in the Appendix R.7.13-2.