Mass Balance Approaches to Assess Critical Loads and Target Loads of Metals for Terrestrial and Aquatic Ecosystems

2015 ◽  
pp. 207-222
Author(s):  
Wim de Vries ◽  
Jan E. Groenenberg ◽  
Maximilian Posch
Keyword(s):  
Mass Balance ◽  
Critical Loads ◽  
Aquatic Ecosystems

scholarly journals Estimates of Exceedances of Critical Loads for Acidifying Deposition in Alberta and Saskatchewan

2018 ◽  
Author(s):  
Paul A. Makar ◽  
Ayodeji Akingunola ◽  
Julian Aherne ◽  
Amanda S. Cole ◽  
Yayne-abeba Aklilu ◽  
...  
Keyword(s):  
Critical Load ◽  
Critical Loads ◽  
Oil Sands ◽  
Aquatic Ecosystems ◽  
Reasonable Agreement ◽  
Base Cation ◽  
Spatial Extent ◽  
Fugitive Dust ◽  
Sulphur Deposition ◽  
Total Deposition

Abstract. Estimates of potential harmful effects to ecosystems in the Canadian provinces of Alberta and Saskatchewan due to acidifying deposition were calculated, using a one year simulation of a high resolution implementation of the Global Environmental Multiscale – Modelling Air-quality and Chemistry (GEM-MACH) model, and estimates of aquatic and terrestrial ecosystem critical loads. The model simulation was evaluated against two different sources of deposition data; total deposition in precipitation and total deposition to snowpack in the vicinity of the Athabasca oil sands. The model captured much of the variability of observed ions in wet deposition in precipitation (observed versus model sulphur, nitrogen and base cation R2 values of 0.90, 0.76 and 0.72, respectively), while being biased high for sulphur deposition, and low for nitrogen and base cations (slopes 2.2, 0.89 and 0.40, respectively). Aircraft-observation-based estimates of fugitive dust emissions, shown to be a factor of ten higher than reported values (Zhang et al., 2017), were used to estimate the impact of increased levels of fugitive dust on model results. Model comparisons to open snowpack observations were shown to be biased high, but in reasonable agreement for sulphur deposition when observations were corrected to account for throughfall in needleleaf forests. The model-observation relationships for precipitation deposition data, along with the expected effects of increased (unreported) base cation emissions, were used to provide a simple observation-based correction to model deposition fields. Base cation deposition was estimated using published observations of base cation fractions in surface collected particles (Wang et al., 2015). Both original and observation-corrected model estimates of sulphur, nitrogen and base cation deposition were used in conjunction with critical load data created using the NEG-ECP (2001) and CLRTAP (2004, 2016, 2017) protocols for critical loads, using variations on the Simple Mass Balance model for forest and terrestrial ecosystems, and the Steady State Water Chemistry and the First-order Acidity Balance models for aquatic ecosystems. Potential ecosystem damage at 2013/14 emissions and deposition levels was predicted for regions within each of the ecosystem critical load datasets examined here. The spatial extent of the regions in exceedance of critical loads varied between 1 × 104 and 3.3 × 105 km2, for the more conservative observation-corrected estimates of deposition, with the variation dependant on the ecosystem and critical load protocol. The larger estimates (for aquatic ecosystems) represent a substantial fraction of the area of the provinces examined. Base cation deposition was shown to have a neutralizing effect on acidifying deposition, and the use of the aircraft and precipitation observation-based corrections to base cation deposition resulted in reasonable agreement with snowpack data collected in the oil sands area. However, critical load exceedances calculated using both observations and observation-corrected deposition suggest that the neutralization effect is limited in spatial extent, decreasing rapidly with distance from emissions sources, due to the rapid deposition of emitted primary particles dust particles as a function of their size.

Uncertainty in mass balance critical loads and exceedance: Application to a UK national data set

2006 ◽  
Vol 40 (32) ◽  
pp. 6146-6153 ◽  
Author(s):  
L HEYWOOD ◽  
J HALL ◽  
R SMITH
Keyword(s):  
Mass Balance ◽  
Critical Loads ◽  
National Data ◽  
Data Set

scholarly journals Estimates of exceedances of critical loads for acidifying deposition in Alberta and Saskatchewan

2018 ◽  
Vol 18 (13) ◽  
pp. 9897-9927 ◽  
Author(s):  
Paul A. Makar ◽  
Ayodeji Akingunola ◽  
Julian Aherne ◽  
Amanda S. Cole ◽  
Yayne-abeba Aklilu ◽  
...  
Keyword(s):  
Critical Load ◽  
Critical Loads ◽  
Oil Sands ◽  
Aquatic Ecosystems ◽  
Reasonable Agreement ◽  
Base Cation ◽  
Spatial Extent ◽  
Sulfur Deposition ◽  
Fugitive Dust ◽  
Emissions Inventories

Abstract. Estimates of potential harmful effects on ecosystems in the Canadian provinces of Alberta and Saskatchewan due to acidifying deposition were calculated, using a 1-year simulation of a high-resolution implementation of the Global Environmental Multiscale-Modelling Air-quality and Chemistry (GEM-MACH) model, and estimates of aquatic and terrestrial ecosystem critical loads. The model simulation was evaluated against two different sources of deposition data: total deposition in precipitation and total deposition to snowpack in the vicinity of the Athabasca oil sands. The model captured much of the variability of observed ions in wet deposition in precipitation (observed versus model sulfur, nitrogen and base cation R2 values of 0.90, 0.76 and 0.72, respectively), while being biased high for sulfur deposition, and low for nitrogen and base cations (slopes 2.2, 0.89 and 0.40, respectively). Aircraft-based estimates of fugitive dust emissions, shown to be a factor of 10 higher than reported to national emissions inventories (Zhang et al., 2018), were used to estimate the impact of increased levels of fugitive dust on model results. Model comparisons to open snowpack observations were shown to be biased high, but in reasonable agreement for sulfur deposition when observations were corrected to account for throughfall in needleleaf forests. The model–observation relationships for precipitation deposition data, along with the expected effects of increased (unreported) base cation emissions, were used to provide a simple observation-based correction to model deposition fields. Base cation deposition was estimated using published observations of base cation fractions in surface-collected particles (Wang et al., 2015).Both original and observation-corrected model estimates of sulfur, nitrogen, and base cation deposition were used in conjunction with critical load data created using the NEG-ECP (2001) and CLRTAP (2017) methods for calculating critical loads, using variations on the Simple Mass Balance model for terrestrial ecosystems, and the Steady State Water Chemistry and First-order Acidity Balance models for aquatic ecosystems. Potential ecosystem damage was predicted within each of the regions represented by the ecosystem critical load datasets used here, using a combination of 2011 and 2013 emissions inventories. The spatial extent of the regions in exceedance of critical loads varied between 1  ×  104 and 3.3  ×  105 km2, for the more conservative observation-corrected estimates of deposition, with the variation dependent on the ecosystem and critical load calculation methodology. The larger estimates (for aquatic ecosystems) represent a substantial fraction of the area of the provinces examined.Base cation deposition was shown to be sufficiently high in the region to have a neutralizing effect on acidifying deposition, and the use of the aircraft and precipitation observation-based corrections to base cation deposition resulted in reasonable agreement with snowpack data collected in the oil sands area. However, critical load exceedances calculated using both observations and observation-corrected deposition suggest that the neutralization effect is limited in spatial extent, decreasing rapidly with distance from emissions sources, due to the rapid deposition of emitted primary dust particles as a function of their size. We strongly recommend the use of observation-based correction of model-simulated deposition in estimating critical load exceedances, in future work.

Calculating critical loads for acidity with the simple mass balance method

1994 ◽  
Vol 72 (1-4) ◽  
pp. 143-162 ◽  
Author(s):  
Harald Sverdrup ◽  
Wim De Vries
Keyword(s):  
Mass Balance ◽  
Critical Loads ◽  
Balance Method ◽  
Mass Balance Method ◽  
Simple Mass

Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA

2012 ◽  
Vol 166 ◽  
pp. 125-135 ◽  
Author(s):  
Leora Nanus ◽  
David W. Clow ◽  
Jasmine E. Saros ◽  
Verlin C. Stephens ◽  
Donald H. Campbell
Keyword(s):  
Nitrogen Deposition ◽  
Rocky Mountains ◽  
Critical Loads ◽  
Aquatic Ecosystems

scholarly journals Long-term modelling of nitrogen turnover and critical loads in a forested catchment using the INCA model

2002 ◽  
Vol 6 (3) ◽  
pp. 395-402 ◽  
Author(s):  
J.-J. Langusch ◽  
E. Matzner
Keyword(s):  
Steady State ◽  
Critical Load ◽  
Mass Balance ◽  
Critical Loads ◽  
Forest Ecosystems ◽  
N Deposition ◽  
N Saturation ◽  
Negative Consequences ◽  
Hydrological Conditions

Abstract. Many forest ecosystems in Central Europe have reached the status of N saturation due to chronically high N deposition. In consequence, the NO3 leaching into ground- and surface waters is often substantial. Critical loads have been defined to abate the negative consequences of the NO3 leaching such as soil acidification and nutrient losses. The steady state mass balance method is normally used to calculate critical loads for N deposition in forest ecosystems. However, the steady state mass balance approach is limited because it does not take into account hydrology and the time until the steady state is reached. The aim of this study was to test the suitability of another approach: the dynamic model INCA (Integrated Nitrogen Model for European Catchments). Long-term effects of changing N deposition and critical loads for N were simulated using INCA for the Lehstenbach spruce catchment (Fichtelgebirge, NE Bavaria, Germany) under different hydrological conditions. Long-term scenarios of either increasing or decreasing N deposition indicated that, in this catchment, the response of nitrate concentrations in runoff to changing N deposition is buffered by a large groundwater reservoir. The critical load simulated by the INCA model with respect to a nitrate concentration of 0.4 mg N l–1 as threshold value in runoff was 9.7 kg N ha–1yr–1 compared to 10 kg ha–1yr–1 for the steady state model. Under conditions of lower precipitation (520 mm) the resulting critical load was 7.7 kg N ha–1yr–1 , suggesting the necessity to account for different hydrological conditions when calculating critical loads. The INCA model seems to be suitable to calculate critical loads for N in forested catchments under varying hydrological conditions e.g. as a consequence of climate change. Keywords: forest ecosystem, N saturation, critical load, modelling, long-term scenario, nitrate leaching, critical loads reduction, INCA

Quantifying Uncertainty in Critical Loads: (B) Acidity Mass Balance Critical Loads on a Sensitive Site

2006 ◽  
Vol 169 (1-4) ◽  
pp. 25-46 ◽  
Author(s):  
R. A. Skeffington ◽  
P. G. Whitehead ◽  
J. Abbott
Keyword(s):  
Mass Balance ◽  
Critical Loads ◽  
Sensitive Site ◽  
Quantifying Uncertainty
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