1. AQUATIC EUTROPHICATION: CONTRIBUTION OF AERIAL NH3 IN GALICIA (NW SPAIN)
A. Gallego, A. Hospido, M.T. Moreira and G. Feijoo
Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela. Santiago de Compostela. Spain.
1. Introduction
Depending on the goal and scope of the LCA study, the use of region-specific characterization factors in eutrophication is generally recognized to be useful [1]. In this context, Galicia (NW Spain) is one of the main regions in Europe with a high risk of soil and water eutrophication [2], being aerial ammonium the main substance contributing to N deposition [3].
2. Aquatic eutrophication associated to NH3
To calculate the eutrophication associated to NH3 (EUNH3), the following formula was applied:
EUNH3 = ENH3 * CFNH3 (1)
ENH3 = NH3 emission in Galicia/year (kg NH3/year)
CFNH3 = Characterization factor for NH3 (kg PO43- eq./kg NH3)
In order to calculate the characterization factor, the following formula was adapted from [4]:
CFNH3 = TRNH3 * TNH3 * EFNH3 * EQNH3 (2)
TRNH3 = NH3 transport factor in Galicia (unitless)
TNH3 = % of NH3 emission in productive period in Galicia (unitless)
EFNH3 = NH3 effect factor in Galicia (unitless)
EQNH3 = Equivalency factor (kg PO43- eq./kg NH3)
Figure 1: Galician Reservoir (
3. NH3 emission (ENH3)
Emissions of NH3 in Galicia were calculated following the EMEP/CORINAIR Emission Inventory Guidebook [5].
4. Characterization Factor (CFNH3)
NH3 transport factor (TRNH3) = 0.24
NH3 deposition is very rapid so the main impacts are very close to the source [6].
The net NH3 flux in nearby regions is assumed to be 0 [7]. NH3 is considered to deposit uniformly in the continental waters.
This area (9,196 km2) represents 24 % of the surface of Galicia (terrestrial plus continental shelf surface).
NH3 effect factor (EFNH3) = 1
Generally N is considered the limiting element in coastal waters and P in freshwaters; however, those assumptions are under revision and for Galicia the limiting element is not clear yet and needs further study. Following recommendations from reference [4], the worst case was considered.
NH3 emission in productive period (TNH3) = 0.74
With data from 108 Galician meteorological stations [8] it has been established that the biological productive period for Galicia is 8.91 months/year (74 %).
Uniform emission is assumed.
Equivalency factor (EQNH3) = 0.35 Kg PO43- eq./kg NH3
It was calculated on the basis of the Redfield ratio [9]
Table 1: Total emission of NH3 in Galicia (for year 2001)
Sources
Emission (ton of NH3)
Cattle
60,638
Agricultural use of fertilizers
4,790
Waste treatment
97.4
Humans and pet animals
276
Wild animals
137
Forest
548
Natural grassland
206
Industry
525
Mobile sources
781
Residential use of coal and biomass
12.0
Agricultural use of sludge
8.25
Products used at home
67.3
Fires
447
Pulses
1.99
Total
68,534
5. Conclusions
EUNH3 = 68,5341,000 (kg NH3) *[0.74*0.24*1*0.35 (kg PO43-/kg NH3)]= 4,082,570 kg PO43- equivalent
6. References
1. Huijbregts, M.A.J., et al. Journal of Industrial Ecology, (3): p
2. EEA. Analysis and mapping of soil problem areas (Hot spots). Final Report. Environmental European Agency. Copenhagen, Denmark
3. Rodríguez, L. and F. Macías. Chemosphere, : p
4. Seppälä, J., S. Knuuttila, and K. Silvo. International Journal of LCA, (2): p
5. EEA, EMEP/CORINAIR Emission Inventory Guidebook - 3rd edition. Technical report No. 30. Environmental European Agency. Copenhagen, Denmark
6. Spokes, L.C. and T.D. Jickells. Continental shelf research, : p
7. EMEP. Diciembre [cited.
8. Carballeira, A., et al., Bioclimatología de Galicia. La Coruña, Spain
9. Heijungs, R., et al., Environmental Life Cycle Assessment of Products.Centre of Environmental Science (CML). Leiden University, The Netherlands
7. Acknowledgements
This work was financed by the Regional Government of Galicia, Xunta de Galicia (Project Reference: PGIDIT04TAL269003PR ) and by the European Union (Project Reference: NMP2-CT )