Fate. Xxxx-known, general multimedia fate models include XxxxXXX (Mackay et al., 1991; Mackay et al., 1996B, CEMC, 2003), CalTOX (XxXxxx, 1993; XxXxxx et al., 2001), SimpleBox (Xxx xx Xxxxx, 1993; Xxxxxxx et al., 1996; Xxx Xxxxxxxxx & Xxx xx Xxxxx, 2004), HAZCHEM (Xxxxxxxx, 1994), CemoS (Xxxxxx et al., 1995), Globo-POP (Xxxxx & Mackay, 1995), EQC (Mackay et al., 1996A), models of the BETR series (XxxXxxx et al., 2001, Xxxxxxxxxxx et al., 2004; Xxxxx et al., 2004; XxxXxxx et al., 2005), X-XXXXX (Xxxxxx et al., 2004) and MATSON (Xxxxxxxx, 2006). The SimpleBox multimedia fate model is included in the combined fate, exposure and effect models USES (RIVM, VROM, MVC, 1994; Xxxxxxx & Xxxxx, 1997; Xxxxxxx & Xxxxxx, 1999) and EUSES (ECB, 1997; EC, 2004), that have been developed for HERA-purposes. The CalTOX model is also a combined fate and * These include overseas territories (like Réunion) and uninhabited areas (like Antarctica). exposure model. Most multimedia models are box models that are based on the assumption of instantaneous homogeneous mixing within each (sub)compartment. Globo-POP, BETR-global and BETR-world are global scale, spatially differenti- ated fate models. In Globo-POP, the world is divided into nine segments, the boundaries of which are based on climate types for each hemisphere. In BETR- world, the world is divided into 25 parts, roughly consisting of partial continents and oceans, respectively. Both models have been designed primarily as ‘pure’ fate models for analytical environmental purposes. A special feature of global multimedia fate models is the fact that polar regions are included in these models. Since frozen soil and water surfaces cause deviations in substance behaviour compared to the behaviour predicted by the conventional equations for substance fate, adapted modelling assumptions are needed for these regions. In Globo-POP, diffusion processes between air and frozen water and soil surfaces are switched off at below zero temperatures. Models that have been widely used for LCA toxicity assessment include CalTOX and USES. CalTOX is used as a stand-alone LCA toxicity characterisation model (Hertwich et al., 2001) and is also applied for toxicity assessment in the LCA model XXXXX (Bare et al., 2002). USES is used as a basis for the adapted model USES- LCA (Huijbregts et al., 2000), which has been used for the calculation of the LCA toxicity characterisation factors that are included in the CML Handbook on Life Gycle Assessment (Guinée et al., 2002). Besides multimedia fate models, the long range air transport model EcoSense (Xxxxxxx et al., 1998A) has been used for LCA as well (Xxxxxxx et al., 1998B). Con- trary to the multimedia models, the EcoSense model does not assume homogene- ous mixing within the air compartments. The model consists of a combination of two model types: a Gaussian plume model for the short distances and a trajectory model – including a wind rose approach by use of the Mind rose Model Inter- preter (MMI) – for the long distance transport. The model – which has a high degree of spatial differentiation on a grid basis – has been implemented for Europe, Asia and the America’s, but not for Africa, Oceania, Antarctica and the ocean regions. A similar approach, by use of a combination of the EUTREND Gaussian plume model (Xxx Xxxxxxxxx & Xx Xxxxx, 1993; Xxx Xxxxxxxxx, 1995; Xxx Xxxxxxxxx et al., 1997) and a trajectory model, based on an adapted version of the EcoSense MMI, has been developed by Potting (2000), and subsequently in- troduced in the EDIP2003 model (Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005). This last model has been implemented for Europe only. Mith respect to air transport, the long range air transport models are far more accurate than the multimedia box models. Generally they do not, however, account for the mutual exchange between air on the one hand and surface water and soil on the other, or for water flows between different regions. Spatial differentiation is lim- ited to the air compartments. Some LCIA models contain their own implicit fate models. These models include EDIP (Xxxxxxxxx & Xxxxxx, 1998; Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005) and IMPACT 2002 (Xxxxxxx et al., 2003; Xxxxxxxxxx et al., 2005). The original EDIP97 toxicity factors (Xxxxxxxxx & Xxxxxx, 1998) used to include degradation measures and a simplified approach for multimedia transport. The EDIP2003 model (Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005) is sup- plemented with a detailed air transport model, as described above. Mith respect to the updated EDIP2006 factors, available through the internet (LCA Center, 2008), it is briefly mentioned that ‘more multimedia transport’ has now been included. The IMPACT 2002 model (Xxxxxxx et al., 2003; Xxxxxxxxxx et al., 2005) contains its own multimedia fate model, parameterised for Mestern Europe in two versions: a spatially differentiated and a general, non-differentiated version respectively. Spa- tial differentiation is based on a grid for air distribution, while for water distribu- tion, it is based on the demarcation of watersheds. Several authors have introduced spatial differentiation into comprehensive LCA impact assessment models (cf. Xxxxxxxxxx et al., 2003; Xxxxxxxxx and Xxxxxxx, 2005; Xxxxxxx and Xxxxxxxxx, 2005; Xxxxxxxxxx et al., 2005; Xxxxxx et al., 2006; Xxxxxxx et al., 2009). In some spatially differentiated multimedia models, a difference is made between an evaluative region (for which emissions can be entered in the model) and a larger, encompassing region of dispersion, in which the emission region is nested. In the USES-LCA model (Huijbregts et al., 2000; Xxx Xxxx et al., 2009), the evaluative region at the continental level (Mestern Europe) is not spa- tially differentiated, but the dispersion region (the northern hemisphere) is charac- terised by its own environmental parameters for three different climate zones. Xxxxxxxxxx et al. (2003) evaluated the influence of spatial differentiation at the con- tinental level by comparing three different versions of the USES-LCA model, with Mestern Europe, the United States and Australia as three alternative continental levels. Xxxxxxxxxx et al. (2005) have introduced spatial differentiation in the IMPACT 2002 model at three levels: the level of Mestern European watersheds (for soil and surface water) and grid cells (for air and sea/ocean), the continental level of Mestern Europe, and the global level, in which the continental level is nested. Emissions can be entered at the watershed/grid cell or at the continental level. Xxxxxx et al. (2006) have applied spatial differentiation at the level of xxxxx- nents to a global version of the IMPACT 2002 model with respect to both emis- sion and dispersion. Another regionally differentiated multimedia model, that has not been designed specifically for LCA, but that has been used in the LCA- context, is BETR-North America (XxxXxxx et al., 2001). This model comprises North America, differentiated at the level of ecological regions. Xxxxxxx et al. (2009) recently developed the IMPACT North America model, in which the evaluative region North America – which is nested into a global dispersion level – is differentiated at the level of several hundred zones. The introduction of metals in multimedia fate models causes some problems, es- pecially in the context of LCA. It has often been remarked that metal speciation models should be included in LCA. Since metals are not degradable, calculated environmental concentrations may become extremely high in closed modelling systems, especially in the surface water compartments where metals tend to end up. As a result, the characterisation factors of metals may become disproportion- ally large, causing metal emission to dominate environmental profiles in a way that cannot be considered plausible. Critics on these extremely high characterisation factors from the side of metal specialists have been accounted for by LCA special- ists, resulting in a common workshop with specialists from both sides in Montréal (Canada) in 2002 (Dubreuil, 2005), commissioned by the UNEP/SETAC Life Cycle Initiative and the International Council on Mining and Metals (ICMM) and a workshop in Apeldoorn (The Netherlands) in 2004, commissioned by ICMM (Aboussouan, 2004). The Apeldoorn workshop resulted in the so-called Apeldoorn Declaration, a list of common goals, described in a final report (Heijungs et al., 2004). In the context of these goals, an international cooperation project was started up with CML, the Radboud University in Nijmegen (The Netherlands) and Toronto University (Canada), in order to combine the Canadian TRANSPEC model for the behaviour of metals in surface water (Xxxxxxx et al., 2004) with LCA toxicity characterisation modelling. Despite the fact that speciation and complexation have not yet been included in the well-known overall LCA characterisation models, not all models suffer from the problem of extremely high characterisation factors. In the CalTOX model, this problem is avoided by the assumption that the residence time of metals in the surface water compartment is limited to one year (Hertwich et al., 2001). In the EDIP model, sediment is not considered to be part of the environmental system which implies that the sedimentation process is not counterbalanced by resuspen- sion. This causes an effective outflow of metals from the environmental system by sedimentation (Xxxxxxxxx & Xxxxxxx, 2005). Besides the TRANSPEC model – an extension of earlier models for the distribution of chemicals in surface water (Diamond et al., 1990, 1992, 1994 and 1999) which is specifically constructed for the behaviour of metals in surface water – another potentially promising model is MATSON (Xxxxxxxx, 2006). This last model accounts specifically for the behav- iour of metals in soil and surface water in Europe, with a fine-meshed system of spatial differentiation. MATSON is an extension to water and soil of the long range air transport model EcoSense mentioned above (Xxxxxxx et al., 1998A). As a basis for the GLOBOX model, we have chosen the EUSES 2.0 model of the European Commission (EC, 2004), since this is a well-documented, recently up- dated model that includes both fate and human exposure modelling and that has a broad public support. The fate model included in EUSES 2.0 is SimpleBox 3.0 (Xxx Xxxxxxxxx & Xxx xx Xxxxx, 2004). A core characteristic of the GLOBOX model is the extension of the model to the global scale and the introduction of spatial differentiation. The model is also supplemented with three extra compart- ments: the freshwater is split up into a river and a lake compartment, and both salt lakes and groundwater are distinguished as separate compartments. Furthermore, the model specifically accounts for cold regions, and contains a specific module for the assessment of metals. Many default values for environmental features – e.g., river flows, lake area and depth and residence times in freshwater compartments – have been replaced by regionally specific values that have been collected from literature. For permanently and temporally frozen water and soil surfaces, absorp- tion and volatilisation processes are switched off for the fraction of time that the local average monthly temperature is below 0 °C. For Greenland and Antarctica, the residence time of runoff water is set to the value of a thousand years. For met- als, specific equations are added in order to account for speciation that may largely diminish bioavailability. This enhances the reliability of the exposure assessment for metals. Accumulation of metals is prevented by the choice for two different sea compartments: an upper mixed layer (100 m) and a deeper layer. The deeper layer is considered to be located outside the environmental system, thus acting as a sink for poorly degradable substances. Exchange between seawater and sea sedi- ment occurs in the shallow seas, where the total depth does not exceed the mixing depth.
Appears in 1 contract
Fate. Xxxx-known, general multimedia fate models include XxxxXXX ChemCAN (Mackay Xxxxxx et al., 1991; Mackay Xxxxxx et al., 1996B, CEMC, 2003), CalTOX (XxXxxx, 1993; XxXxxx et al., 2001), SimpleBox (Xxx xx Xxxxx, 1993; Xxxxxxx et al., 1996; Xxx Xxxxxxxxx & Xxx xx Xxxxx, 2004), HAZCHEM (Xxxxxxxx, 1994), CemoS (Xxxxxx et al., 1995), Globo-POP (Xxxxx & MackayXxxxxx, 1995), EQC (Mackay Xxxxxx et al., 1996A), models of the BETR series (XxxXxxx et al., 2001, Xxxxxxxxxxx et al., 2004; Xxxxx et al., 2004; XxxXxxx et al., 2005), XG-XXXXX CIEMS (Xxxxxx Suzuki et al., 2004) and MATSON (Xxxxxxxx, 2006). The SimpleBox multimedia fate model is included in the combined fate, exposure and effect models USES (RIVM, VROM, MVC, 1994; Xxxxxxx & Xxxxx, 1997; Xxxxxxx & Xxxxxx, 1999) and EUSES (ECB, 1997; EC, 2004), that have been developed for HERA-purposes. The CalTOX model is also a combined fate and * These include overseas territories (like Réunion) and uninhabited areas (like Antarctica). exposure model. Most multimedia models are box models that are based on the assumption of instantaneous homogeneous mixing within each (sub)compartment. Globo-POP, BETR-global and BETR-world are global scale, spatially differenti- ated fate models. In Globo-POP, the world is divided into nine segments, the boundaries of which are based on climate types for each hemisphere. In BETR- world, the world is divided into 25 parts, roughly consisting of partial continents and oceans, respectively. Both models have been designed primarily as ‘pure’ fate models for analytical environmental purposes. A special feature of global multimedia fate models is the fact that polar regions are included in these models. Since frozen soil and water surfaces cause deviations in substance behaviour compared to the behaviour predicted by the conventional equations for substance fate, adapted modelling assumptions are needed for these regions. In Globo-POP, diffusion processes between air and frozen water and soil surfaces are switched off at below zero temperatures. Models that have been widely used for LCA toxicity assessment include CalTOX and USES. CalTOX is used as a stand-alone LCA toxicity characterisation model (Hertwich et al., 2001) and is also applied for toxicity assessment in the LCA model XXXXX (Bare et al., 2002). USES is used as a basis for the adapted model USES- LCA (Huijbregts et al., 2000), which has been used for the calculation of the LCA toxicity characterisation factors that are included in the CML Handbook on Life Gycle Assessment (Guinée Xxxxxx et al., 2002). Besides multimedia fate models, the long range air transport model EcoSense (Xxxxxxx et al., 1998A) has been used for LCA as well (Xxxxxxx et al., 1998B). Con- trary to the multimedia models, the EcoSense model does not assume homogene- ous mixing within the air compartments. The model consists of a combination of two model types: a Gaussian plume model for the short distances and a trajectory model – including a wind rose approach by use of the Mind rose Model Inter- preter (MMI) – for the long distance transport. The model – which has a high degree of spatial differentiation on a grid basis – has been implemented for Europe, Asia and the America’s, but not for Africa, Oceania, Antarctica and the ocean regions. A similar approach, by use of a combination of the EUTREND Gaussian plume model (Xxx Xxxxxxxxx & Xx Xxxxx, 1993; Xxx Xxxxxxxxx, 1995; Xxx Xxxxxxxxx et al., 1997) and a trajectory model, based on an adapted version of the EcoSense MMI, has been developed by Potting (2000), and subsequently in- troduced in the EDIP2003 model (Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005). This last model has been implemented for Europe only. Mith respect to air transport, the long range air transport models are far more accurate than the multimedia box models. Generally they do not, however, account for the mutual exchange between air on the one hand and surface water and soil on the other, or for water flows between different regions. Spatial differentiation is lim- ited to the air compartments. Some LCIA models contain their own implicit fate models. These models include EDIP (Xxxxxxxxx & Xxxxxx, 1998; Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005) and IMPACT 2002 (Xxxxxxx et al., 2003; Xxxxxxxxxx et al., 2005). The original EDIP97 toxicity factors (Xxxxxxxxx & Xxxxxx, 1998) used to include degradation measures and a simplified approach for multimedia transport. The EDIP2003 model (Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005) is sup- plemented with a detailed air transport model, as described above. Mith respect to the updated EDIP2006 factors, available through the internet (LCA Center, 2008), it is briefly mentioned that ‘more multimedia transport’ has now been included. The IMPACT 2002 model (Xxxxxxx et al., 2003; Xxxxxxxxxx et al., 2005) contains its own multimedia fate model, parameterised for Mestern Europe in two versions: a spatially differentiated and a general, non-differentiated version respectively. Spa- tial differentiation is based on a grid for air distribution, while for water distribu- tion, it is based on the demarcation of watersheds. Several authors have introduced spatial differentiation into comprehensive LCA impact assessment models (cf. Xxxxxxxxxx et al., 2003; Xxxxxxxxx and Xxxxxxx, 2005; Xxxxxxx and Xxxxxxxxx, 2005; Xxxxxxxxxx et al., 2005; Xxxxxx et al., 2006; Xxxxxxx et al., 2009). In some spatially differentiated multimedia models, a difference is made between an evaluative region (for which emissions can be entered in the model) and a larger, encompassing region of dispersion, in which the emission region is nested. In the USES-LCA model (Huijbregts et al., 2000; Xxx Xxxx Van Zelm et al., 2009), the evaluative region at the continental level (Mestern Europe) is not spa- tially differentiated, but the dispersion region (the northern hemisphere) is charac- terised by its own environmental parameters for three different climate zones. Xxxxxxxxxx et al. (2003) evaluated the influence of spatial differentiation at the con- tinental level by comparing three different versions of the USES-LCA model, with Mestern Europe, the United States and Australia as three alternative continental levels. Xxxxxxxxxx et al. (2005) have introduced spatial differentiation in the IMPACT 2002 model at three levels: the level of Mestern European watersheds (for soil and surface water) and grid cells (for air and sea/ocean), the continental level of Mestern Europe, and the global level, in which the continental level is nested. Emissions can be entered at the watershed/grid cell or at the continental level. Xxxxxx et al. (2006) have applied spatial differentiation at the level of xxxxx- nents to a global version of the IMPACT 2002 model with respect to both emis- sion and dispersion. Another regionally differentiated multimedia model, that has not been designed specifically for LCA, but that has been used in the LCA- context, is BETR-North America (XxxXxxx et al., 2001). This model comprises North America, differentiated at the level of ecological regions. Xxxxxxx et al. (2009) recently developed the IMPACT North America model, in which the evaluative region North America – which is nested into a global dispersion level – is differentiated at the level of several hundred zones. The introduction of metals in multimedia fate models causes some problems, es- pecially in the context of LCA. It has often been remarked that metal speciation models should be included in LCA. Since metals are not degradable, calculated environmental concentrations may become extremely high in closed modelling systems, especially in the surface water compartments where metals tend to end up. As a result, the characterisation factors of metals may become disproportion- ally large, causing metal emission to dominate environmental profiles in a way that cannot be considered plausible. Critics on these extremely high characterisation factors from the side of metal specialists have been accounted for by LCA special- ists, resulting in a common workshop with specialists from both sides in Montréal (Canada) in 2002 (Dubreuil, 2005), commissioned by the UNEP/SETAC Life Cycle Initiative and the International Council on Mining and Metals (ICMM) and a workshop in Apeldoorn (The Netherlands) in 2004, commissioned by ICMM (Aboussouan, 2004). The Apeldoorn workshop resulted in the so-called Apeldoorn Declaration, a list of common goals, described in a final report (Heijungs et al., 2004). In the context of these goals, an international cooperation project was started up with CML, the Radboud University in Nijmegen (The Netherlands) and Toronto University (Canada), in order to combine the Canadian TRANSPEC model for the behaviour of metals in surface water (Xxxxxxx et al., 2004) with LCA toxicity characterisation modelling. Despite the fact that speciation and complexation have not yet been included in the well-known overall LCA characterisation models, not all models suffer from the problem of extremely high characterisation factors. In the CalTOX model, this problem is avoided by the assumption that the residence time of metals in the surface water compartment is limited to one year (Hertwich et al., 2001). In the EDIP model, sediment is not considered to be part of the environmental system which implies that the sedimentation process is not counterbalanced by resuspen- sion. This causes an effective outflow of metals from the environmental system by sedimentation (Xxxxxxxxx & Xxxxxxx, 2005). Besides the TRANSPEC model – an extension of earlier models for the distribution of chemicals in surface water (Diamond et al., 1990, 1992, 1994 and 1999) which is specifically constructed for the behaviour of metals in surface water – another potentially promising model is MATSON (Xxxxxxxx, 2006). This last model accounts specifically for the behav- iour of metals in soil and surface water in Europe, with a fine-meshed system of spatial differentiation. MATSON is an extension to water and soil of the long range air transport model EcoSense mentioned above (Xxxxxxx et al., 1998A). As a basis for the GLOBOX model, we have chosen the EUSES 2.0 model of the European Commission (EC, 2004), since this is a well-documented, recently up- dated model that includes both fate and human exposure modelling and that has a broad public support. The fate model included in EUSES 2.0 is SimpleBox 3.0 (Xxx Xxxxxxxxx & Xxx xx Xxxxx, 2004). A core characteristic of the GLOBOX model is the extension of the model to the global scale and the introduction of spatial differentiation. The model is also supplemented with three extra compart- ments: the freshwater is split up into a river and a lake compartment, and both salt lakes and groundwater are distinguished as separate compartments. Furthermore, the model specifically accounts for cold regions, and contains a specific module for the assessment of metals. Many default values for environmental features – e.g., river flows, lake area and depth and residence times in freshwater compartments – have been replaced by regionally specific values that have been collected from literature. For permanently and temporally frozen water and soil surfaces, absorp- tion and volatilisation processes are switched off for the fraction of time that the local average monthly temperature is below 0 °C. For Greenland and Antarctica, the residence time of runoff water is set to the value of a thousand years. For met- als, specific equations are added in order to account for speciation that may largely diminish bioavailability. This enhances the reliability of the exposure assessment for metals. Accumulation of metals is prevented by the choice for two different sea compartments: an upper mixed layer (100 m) and a deeper layer. The deeper layer is considered to be located outside the environmental system, thus acting as a sink for poorly degradable substances. Exchange between seawater and sea sedi- ment occurs in the shallow seas, where the total depth does not exceed the mixing depth.
Appears in 1 contract
Fate. Xxxx-known, general multimedia fate models include XxxxXXX (Mackay Xxxxxx et al., 1991; Mackay Xxxxxx et al., 1996B, CEMC, 2003), CalTOX (XxXxxx, 1993; XxXxxx et al., 2001), SimpleBox (Xxx xx Xxxxx, 1993; Xxxxxxx et al., 1996; Xxx Xxxxxxxxx & Xxx xx Xxxxx, 2004), HAZCHEM (Xxxxxxxx, 1994), CemoS (Xxxxxx et al., 1995), Globo-POP (Xxxxx & MackayXxxxxx, 1995), EQC (Mackay Xxxxxx et al., 1996A), models of the BETR series (XxxXxxx et al., 2001, Xxxxxxxxxxx et al., 2004; Xxxxx et al., 2004; XxxXxxx et al., 2005), X-XXXXX (Xxxxxx Suzuki et al., 2004) and MATSON (Xxxxxxxx, 2006). The SimpleBox multimedia fate model is included in the combined fate, exposure and effect models USES (RIVM, VROM, MVC, 1994; Xxxxxxx & Xxxxx, 1997; Xxxxxxx & Xxxxxx, 1999) and EUSES (ECB, 1997; EC, 2004), that have been developed for HERA-purposes. The CalTOX model is also a combined fate and * These include overseas territories (like Réunion) and uninhabited areas (like Antarctica). exposure model. Most multimedia models are box models that are based on the assumption of instantaneous homogeneous mixing within each (sub)compartment. Globo-POP, BETR-global and BETR-world are global scale, spatially differenti- ated fate models. In Globo-POP, the world is divided into nine segments, the boundaries of which are based on climate types for each hemisphere. In BETR- world, the world is divided into 25 parts, roughly consisting of partial continents and oceans, respectively. Both models have been designed primarily as ‘pure’ fate models for analytical environmental purposes. A special feature of global multimedia fate models is the fact that polar regions are included in these models. Since frozen soil and water surfaces cause deviations in substance behaviour compared to the behaviour predicted by the conventional equations for substance fate, adapted modelling assumptions are needed for these regions. In Globo-POP, diffusion processes between air and frozen water and soil surfaces are switched off at below zero temperatures. Models that have been widely used for LCA toxicity assessment include CalTOX and USES. CalTOX is used as a stand-alone LCA toxicity characterisation model (Hertwich et al., 2001) and is also applied for toxicity assessment in the LCA model XXXXX (Bare et al., 2002). USES is used as a basis for the adapted model USES- LCA (Huijbregts et al., 2000), which has been used for the calculation of the LCA toxicity characterisation factors that are included in the CML Handbook on Life Gycle Assessment (Guinée et al., 2002). Besides multimedia fate models, the long range air transport model EcoSense (Xxxxxxx et al., 1998A) has been used for LCA as well (Xxxxxxx et al., 1998B). Con- trary to the multimedia models, the EcoSense model does not assume homogene- ous mixing within the air compartments. The model consists of a combination of two model types: a Gaussian plume model for the short distances and a trajectory model – including a wind rose approach by use of the Mind rose Model Inter- preter (MMI) – for the long distance transport. The model – which has a high degree of spatial differentiation on a grid basis – has been implemented for Europe, Asia and the America’s, but not for Africa, Oceania, Antarctica and the ocean regions. A similar approach, by use of a combination of the EUTREND Gaussian plume model (Xxx Xxxxxxxxx & Xx Xxxxx, 1993; Xxx Xxxxxxxxx, 1995; Xxx Xxxxxxxxx et al., 1997) and a trajectory model, based on an adapted version of the EcoSense MMI, has been developed by Potting (2000), and subsequently in- troduced in the EDIP2003 model (Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005). This last model has been implemented for Europe only. Mith respect to air transport, the long range air transport models are far more accurate than the multimedia box models. Generally they do not, however, account for the mutual exchange between air on the one hand and surface water and soil on the other, or for water flows between different regions. Spatial differentiation is lim- ited to the air compartments. Some LCIA models contain their own implicit fate models. These models include EDIP (Xxxxxxxxx & Xxxxxx, 1998; Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005) and IMPACT 2002 (Xxxxxxx et al., 2003; Xxxxxxxxxx et al., 2005). The original EDIP97 toxicity factors (Xxxxxxxxx & Xxxxxx, 1998) used to include degradation measures and a simplified approach for multimedia transport. The EDIP2003 model (Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005) is sup- plemented with a detailed air transport model, as described above. Mith respect to the updated EDIP2006 factors, available through the internet (LCA Center, 2008), it is briefly mentioned that ‘more multimedia transport’ has now been included. The IMPACT 2002 model (Xxxxxxx et al., 2003; Xxxxxxxxxx et al., 2005) contains its own multimedia fate model, parameterised for Mestern Europe in two versions: a spatially differentiated and a general, non-differentiated version respectively. Spa- tial differentiation is based on a grid for air distribution, while for water distribu- tion, it is based on the demarcation of watersheds. Several authors have introduced spatial differentiation into comprehensive LCA impact assessment models (cf. Xxxxxxxxxx et al., 2003; Xxxxxxxxx and Xxxxxxx, 2005; Xxxxxxx and Xxxxxxxxx, 2005; Xxxxxxxxxx et al., 2005; Xxxxxx et al., 2006; Xxxxxxx et al., 2009). In some spatially differentiated multimedia models, a difference is made between an evaluative region (for which emissions can be entered in the model) and a larger, encompassing region of dispersion, in which the emission region is nested. In the USES-LCA model (Huijbregts et al., 2000; Xxx Xxxx Van Zelm et al., 2009), the evaluative region at the continental level (Mestern Europe) is not spa- tially differentiated, but the dispersion region (the northern hemisphere) is charac- terised by its own environmental parameters for three different climate zones. Xxxxxxxxxx et al. (2003) evaluated the influence of spatial differentiation at the con- tinental level by comparing three different versions of the USES-LCA model, with Mestern Europe, the United States and Australia as three alternative continental levels. Xxxxxxxxxx et al. (2005) have introduced spatial differentiation in the IMPACT 2002 model at three levels: the level of Mestern European watersheds (for soil and surface water) and grid cells (for air and sea/ocean), the continental level of Mestern Europe, and the global level, in which the continental level is nested. Emissions can be entered at the watershed/grid cell or at the continental level. Xxxxxx et al. (2006) have applied spatial differentiation at the level of xxxxx- nents to a global version of the IMPACT 2002 model with respect to both emis- sion and dispersion. Another regionally differentiated multimedia model, that has not been designed specifically for LCA, but that has been used in the LCA- context, is BETR-North America (XxxXxxx et al., 2001). This model comprises North America, differentiated at the level of ecological regions. Xxxxxxx et al. (2009) recently developed the IMPACT North America model, in which the evaluative region North America – which is nested into a global dispersion level – is differentiated at the level of several hundred zones. The introduction of metals in multimedia fate models causes some problems, es- pecially in the context of LCA. It has often been remarked that metal speciation models should be included in LCA. Since metals are not degradable, calculated environmental concentrations may become extremely high in closed modelling systems, especially in the surface water compartments where metals tend to end up. As a result, the characterisation factors of metals may become disproportion- ally large, causing metal emission to dominate environmental profiles in a way that cannot be considered plausible. Critics on these extremely high characterisation factors from the side of metal specialists have been accounted for by LCA special- ists, resulting in a common workshop with specialists from both sides in Montréal (Canada) in 2002 (DubreuilXxxxxxxx, 2005), commissioned by the UNEP/SETAC Life Cycle Initiative and the International Council on Mining and Metals (ICMM) and a workshop in Apeldoorn (The Netherlands) in 2004, commissioned by ICMM (Aboussouan, 2004). The Apeldoorn workshop resulted in the so-called Apeldoorn Declaration, a list of common goals, described in a final report (Heijungs et al., 2004). In the context of these goals, an international cooperation project was started up with CML, the Radboud University in Nijmegen (The Netherlands) and Toronto University (Canada), in order to combine the Canadian TRANSPEC model for the behaviour of metals in surface water (Xxxxxxx et al., 2004) with LCA toxicity characterisation modelling. Despite the fact that speciation and complexation have not yet been included in the well-known overall LCA characterisation models, not all models suffer from the problem of extremely high characterisation factors. In the CalTOX model, this problem is avoided by the assumption that the residence time of metals in the surface water compartment is limited to one year (Hertwich et al., 2001). In the EDIP model, sediment is not considered to be part of the environmental system which implies that the sedimentation process is not counterbalanced by resuspen- sion. This causes an effective outflow of metals from the environmental system by sedimentation (Xxxxxxxxx & Xxxxxxx, 2005). Besides the TRANSPEC model – an extension of earlier models for the distribution of chemicals in surface water (Diamond et al., 1990, 1992, 1994 and 1999) which is specifically constructed for the behaviour of metals in surface water – another potentially promising model is MATSON (Xxxxxxxx, 2006). This last model accounts specifically for the behav- iour of metals in soil and surface water in Europe, with a fine-meshed system of spatial differentiation. MATSON is an extension to water and soil of the long range air transport model EcoSense mentioned above (Xxxxxxx et al., 1998A). As a basis for the GLOBOX model, we have chosen the EUSES 2.0 model of the European Commission (EC, 2004), since this is a well-documented, recently up- dated model that includes both fate and human exposure modelling and that has a broad public support. The fate model included in EUSES 2.0 is SimpleBox 3.0 (Xxx Xxxxxxxxx & Xxx xx Xxxxx, 2004). A core characteristic of the GLOBOX model is the extension of the model to the global scale and the introduction of spatial differentiation. The model is also supplemented with three extra compart- ments: the freshwater is split up into a river and a lake compartment, and both salt lakes and groundwater are distinguished as separate compartments. Furthermore, the model specifically accounts for cold regions, and contains a specific module for the assessment of metals. Many default values for environmental features – e.g., river flows, lake area and depth and residence times in freshwater compartments – have been replaced by regionally specific values that have been collected from literature. For permanently and temporally frozen water and soil surfaces, absorp- tion and volatilisation processes are switched off for the fraction of time that the local average monthly temperature is below 0 °C. For Greenland and Antarctica, the residence time of runoff water is set to the value of a thousand years. For met- als, specific equations are added in order to account for speciation that may largely diminish bioavailability. This enhances the reliability of the exposure assessment for metals. Accumulation of metals is prevented by the choice for two different sea compartments: an upper mixed layer (100 m) and a deeper layer. The deeper layer is considered to be located outside the environmental system, thus acting as a sink for poorly degradable substances. Exchange between seawater and sea sedi- ment occurs in the shallow seas, where the total depth does not exceed the mixing depth.
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Fate. XxxxWell-known, general multimedia fate models include XxxxXXX (Mackay Xxxxxx et al., 1991; Mackay Xxxxxx et al., 1996B, CEMC, 2003), CalTOX (XxXxxx, 1993; XxXxxx et al., 2001), SimpleBox (Xxx xx Xxxxx, 1993; Xxxxxxx et al., 1996; Xxx Xxxxxxxxx & Xxx xx Xxxxx, 2004), HAZCHEM (Xxxxxxxx, 1994), CemoS (Xxxxxx et al., 1995), Globo-POP (Xxxxx & MackayXxxxxx, 1995), EQC (Mackay Xxxxxx et al., 1996A), models of the BETR series (XxxXxxx et al., 2001, Xxxxxxxxxxx et al., 2004; Xxxxx et al., 2004; XxxXxxx et al., 2005), XG-XXXXX CIEMS (Xxxxxx Suzuki et al., 2004) and MATSON XXXXXX (Xxxxxxxx, 2006). The SimpleBox multimedia fate model is included in the combined fate, exposure and effect models USES (RIVM, VROM, MVCWVC, 1994; Xxxxxxx & Xxxxx, 1997; Xxxxxxx & Xxxxxx, 1999) and EUSES XXXXX (ECB, 1997; EC, 2004), that have been developed for HERA-purposes. The CalTOX model is also a combined fate and * These include overseas territories (like Réunion) and uninhabited areas (like Antarctica). exposure model. Most multimedia models are box models that are based on the assumption of instantaneous homogeneous mixing within each (sub)compartment. Globo-POP, BETR-global and BETR-world are global scale, spatially differenti- ated fate models. In Globo-POP, the world is divided into nine segments, the boundaries of which are based on climate types for each hemisphere. In BETR- world, the world is divided into 25 parts, roughly consisting of partial continents and oceans, respectively. Both models have been designed primarily as ‘pure’ fate models for analytical environmental purposes. A special feature of global multimedia fate models is the fact that polar regions are included in these models. Since frozen soil and water surfaces cause deviations in substance behaviour compared to the behaviour predicted by the conventional equations for substance fate, adapted modelling assumptions are needed for these regions. In Globo-POP, diffusion processes between air and frozen water and soil surfaces are switched off at below zero temperatures. Models that have been widely used for LCA toxicity assessment include CalTOX and USES. CalTOX is used as a stand-alone LCA toxicity characterisation model (Hertwich et al., 2001) and is also applied for toxicity assessment in the LCA model XXXXX (Bare et al., 2002). USES is used as a basis for the adapted model USES- LCA (Huijbregts et al., 2000), which has been used for the calculation of the LCA toxicity characterisation factors that are included in the CML Handbook on Life Gycle Cycle Assessment (Guinée et al., 2002). Besides multimedia fate models, the long range air transport model EcoSense (Xxxxxxx et al., 1998A) has been used for LCA as well (Xxxxxxx et al., 1998B). Con- trary to the multimedia models, the EcoSense model does not assume homogene- ous mixing within the air compartments. The model consists of a combination of two model types: a Gaussian plume model for the short distances and a trajectory model – including a wind rose approach by use of the Mind Wind rose Model Inter- preter (MMIWMI) – for the long distance transport. The model – which has a high degree of spatial differentiation on a grid basis – has been implemented for Europe, Asia and the America’s, but not for Africa, Oceania, Antarctica and the ocean regions. A similar approach, by use of a combination of the EUTREND Gaussian plume model (Xxx Xxxxxxxxx & Xx Xxxxx, 1993; Xxx Xxxxxxxxx, 1995; Xxx Xxxxxxxxx et al., 1997) and a trajectory model, based on an adapted version of the EcoSense MMIWMI, has been developed by Potting (2000), and subsequently in- troduced in the EDIP2003 model (Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx Potting & Xxxxxxxxx, 2005). This last model has been implemented for Europe only. Mith With respect to air transport, the long range air transport models are far more accurate than the multimedia box models. Generally they do not, however, account for the mutual exchange between air on the one hand and surface water and soil on the other, or for water flows between different regions. Spatial differentiation is lim- ited to the air compartments. Some LCIA models contain their own implicit fate models. These models include EDIP (Xxxxxxxxx & Xxxxxx, 1998; Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005) and IMPACT 2002 (Xxxxxxx et al., 2003; Xxxxxxxxxx et al., 2005). The original EDIP97 toxicity factors (Xxxxxxxxx & Xxxxxx, 1998) used to include degradation measures and a simplified approach for multimedia transport. The EDIP2003 model (Xxxxxxxxx & Xxxxxxx, 2005; Xxxxxxx & Xxxxxxxxx, 2005) is sup- plemented with a detailed air transport model, as described above. Mith With respect to the updated EDIP2006 factors, available through the internet (LCA Center, 2008), it is briefly mentioned that ‘more multimedia transport’ has now been included. The IMPACT 2002 model (Xxxxxxx et al., 2003; Xxxxxxxxxx et al., 2005) contains its own multimedia fate model, parameterised for Mestern Western Europe in two versions: a spatially differentiated and a general, non-differentiated version respectively. Spa- tial differentiation is based on a grid for air distribution, while for water distribu- tion, it is based on the demarcation of watersheds. Several authors have introduced spatial differentiation into comprehensive LCA impact assessment models (cf. Xxxxxxxxxx et al., 2003; Xxxxxxxxx and Xxxxxxx, 2005; Xxxxxxx and Xxxxxxxxx, 2005; Xxxxxxxxxx et al., 2005; Xxxxxx et al., 2006; Xxxxxxx et al., 2009). In some spatially differentiated multimedia models, a difference is made between an evaluative region (for which emissions can be entered in the model) and a larger, encompassing region of dispersion, in which the emission region is nested. In the USES-LCA model (Huijbregts et al., 2000; Xxx Xxxx Van Zelm et al., 2009), the evaluative region at the continental level (Mestern Western Europe) is not spa- tially differentiated, but the dispersion region (the northern hemisphere) is charac- terised by its own environmental parameters for three different climate zones. Xxxxxxxxxx et al. (2003) evaluated the influence of spatial differentiation at the con- tinental level by comparing three different versions of the USES-LCA model, with Mestern Western Europe, the United States and Australia as three alternative continental levels. Xxxxxxxxxx et al. (2005) have introduced spatial differentiation in the IMPACT 2002 model at three levels: the level of Mestern Western European watersheds (for soil and surface water) and grid cells (for air and sea/ocean), the continental level of Mestern Western Europe, and the global level, in which the continental level is nested. Emissions can be entered at the watershed/grid cell or at the continental level. Xxxxxx et al. (2006) have applied spatial differentiation at the level of xxxxx- nents to a global version of the IMPACT 2002 model with respect to both emis- sion and dispersion. Another regionally differentiated multimedia model, that has not been designed specifically for LCA, but that has been used in the LCA- context, is BETR-North America (XxxXxxx et al., 2001). This model comprises North America, differentiated at the level of ecological regions. Xxxxxxx et al. (2009) recently developed the IMPACT North America model, in which the evaluative region North America – which is nested into a global dispersion level – is differentiated at the level of several hundred zones. The introduction of metals in multimedia fate models causes some problems, es- pecially in the context of LCA. It has often been remarked that metal speciation models should be included in LCA. Since metals are not degradable, calculated environmental concentrations may become extremely high in closed modelling systems, especially in the surface water compartments where metals tend to end up. As a result, the characterisation factors of metals may become disproportion- ally large, causing metal emission to dominate environmental profiles in a way that cannot be considered plausible. Critics on these extremely high characterisation factors from the side of metal specialists have been accounted for by LCA special- ists, resulting in a common workshop with specialists from both sides in Montréal (Canada) in 2002 (DubreuilXxxxxxxx, 2005), commissioned by the UNEP/SETAC Life Cycle Initiative and the International Council on Mining and Metals (ICMM) and a workshop in Apeldoorn (The Netherlands) in 2004, commissioned by ICMM (Aboussouan, 2004). The Apeldoorn workshop resulted in the so-called Apeldoorn Declaration, a list of common goals, described in a final report (Heijungs et al., 2004). In the context of these goals, an international cooperation project was started up with CML, the Radboud University in Nijmegen (The Netherlands) and Toronto University (Canada), in order to combine the Canadian TRANSPEC model for the behaviour of metals in surface water (Xxxxxxx et al., 2004) with LCA toxicity characterisation modelling. Despite the fact that speciation and complexation have not yet been included in the well-known overall LCA characterisation models, not all models suffer from the problem of extremely high characterisation factors. In the CalTOX model, this problem is avoided by the assumption that the residence time of metals in the surface water compartment is limited to one year (Hertwich et al., 2001). In the EDIP model, sediment is not considered to be part of the environmental system which implies that the sedimentation process is not counterbalanced by resuspen- sion. This causes an effective outflow of metals from the environmental system by sedimentation (Xxxxxxxxx & Xxxxxxx, 2005). Besides the TRANSPEC model – an extension of earlier models for the distribution of chemicals in surface water (Diamond et al., 1990, 1992, 1994 and 1999) which is specifically constructed for the behaviour of metals in surface water – another potentially promising model is MATSON XXXXXX (Xxxxxxxx, 2006). This last model accounts specifically for the behav- iour of metals in soil and surface water in Europe, with a fine-meshed system of spatial differentiation. MATSON XXXXXX is an extension to water and soil of the long range air transport model EcoSense mentioned above (Xxxxxxx et al., 1998A). As a basis for the GLOBOX model, we have chosen the EUSES 2.0 model of the European Commission (EC, 2004), since this is a well-documented, recently up- dated model that includes both fate and human exposure modelling and that has a broad public support. The fate model included in EUSES 2.0 is SimpleBox 3.0 (Xxx Xxxxxxxxx & Xxx xx Xxxxx, 2004). A core characteristic of the GLOBOX model is the extension of the model to the global scale and the introduction of spatial differentiation. The model is also supplemented with three extra compart- ments: the freshwater is split up into a river and a lake compartment, and both salt lakes and groundwater are distinguished as separate compartments. Furthermore, the model specifically accounts for cold regions, and contains a specific module for the assessment of metals. Many default values for environmental features – e.g., river flows, lake area and depth and residence times in freshwater compartments – have been replaced by regionally specific values that have been collected from literature. For permanently and temporally frozen water and soil surfaces, absorp- tion and volatilisation processes are switched off for the fraction of time that the local average monthly temperature is below 0 °C. For Greenland and Antarctica, the residence time of runoff water is set to the value of a thousand years. For met- als, specific equations are added in order to account for speciation that may largely diminish bioavailability. This enhances the reliability of the exposure assessment for metals. Accumulation of metals is prevented by the choice for two different sea compartments: an upper mixed layer (100 m) and a deeper layer. The deeper layer is considered to be located outside the environmental system, thus acting as a sink for poorly degradable substances. Exchange between seawater and sea sedi- ment occurs in the shallow seas, where the total depth does not exceed the mixing depth.
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