Transport of persistent organic pollutants into the Arctic

260 Pages·2006·21.48 MB·English

Transport of persistent organic pollutants
into the Arctic
by
Kaj Mantzius Hansen
PhD thesis
Copenhagen Global Change Initiative, Faculty of Science and
Niels Bohr Institute for Astronomy, Physics and Geophysics
University of Copenhagen
and
National Environmental Research Institute
Department of Atmospheric Environment
May 2006

Transport of persistent
organic pollutants
into the Arctic

PhD Thesis
2006

Kaj Mantzius Hansen

Copenhagen Global Change Initiative, Faculty of
Science, University of Copenhagen

Niels Bohr Institute for Astronomy, Physics and
Geophysics, University of Copenhagen

and

Department of Atmospheric Environment
National Environmental Research Institute
Data sheet

Title: Transport of persistent organic pollutants into the Arctic
Subtitle: PhD thesis

Author: Kaj Mantzius Hansen
Department: Department of Atmospheric Environment

University: Copenhagen Global Change Initiative and The Niels Bohr Institute for
Astronomy, Physics and Geophysics, Faculty of Science, University of
Copenhagen

Publisher: Ministry of the Environment
National Environmental Research Institute
URL: http://www.dmu.dk

Date of publication: May 2006

Please cite as: Hansen, K. M., 2006: Transport of persistent organic pollutants into the
Arctic. PhD thesis. Department of Atmospheric Environment, National
Environmental Research Institute, Roskilde, Denmark. 250 pp.

Reproduction permitted only when quoting is evident

ISBN: 978-87-7772-928-7

Number of pages: 250

Internet version: The report is available only in electronic format from NERI’s homepage.
Internet-version:
http://www2.dmu.dk/1_viden/2_Publikationer/3_Ovrige/rapporter/
KMH_phd.pdf

Supplementary notes: This PhD thesis was submitted to the Faculty of Science, University of
Copenhagen in November 2005. In February 2006 it was recommended
for acceptance by an international evaluation committee.

Front page figure:
Annual average a-HCH concentrations in the lowermost atmospheric layer
for 1992 predicted by the POP version of the Danish Eulerian
Hemispheric Model (DEHM-POP).
i
To my family:
Pernille, the air that I breathe.
Veronika, the sunshine of my life.
Sigrid, a star on the sky at night. I miss you.
ii
Contents
1 Introduction 1
1.1 The objectives of this project . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Structure of the thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Persistent organic pollutants 7
2.1 Groups of POPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1.1 Intentionally produced chemicals . . . . . . . . . . . . . . . . . . . . 7
2.1.2 Accidentally formed chemicals . . . . . . . . . . . . . . . . . . . . . 8
2.2 History of POPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Characteristics of POPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3.1 Environmental partitioning of POPs . . . . . . . . . . . . . . . . . . 10
2.3.2 Physical-chemical properties of POPs . . . . . . . . . . . . . . . . . 12
2.3.3 Environmental fate of POPs . . . . . . . . . . . . . . . . . . . . . . . 14
2.4 Modelling the environmental fate of POPs . . . . . . . . . . . . . . . . . . . 15
2.4.1 Multi-compartment mass balance models . . . . . . . . . . . . . . . 17
2.4.2 Atmospheric chemistry transport models. . . . . . . . . . . . . . . . 18
2.5 Hexachlorocyclohexane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.5.1 Physical-chemical properties of hexachlorocyclohexanes . . . . . . . 20
2.5.2 Environmental partitioning of hexachlorocyclohexanes . . . . . . . . 22
2.5.3 Modelling the environmental fate of HCH . . . . . . . . . . . . . . . 24
3 The model set-up 25
3.1 General description of the model . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2 The basic equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.3 Numerical techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.3.1 Splitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.3.2 Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.3.3 Time step . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.3.4 Boundary and initial conditions . . . . . . . . . . . . . . . . . . . . . 31
3.4 Horizontal and vertical diffusion . . . . . . . . . . . . . . . . . . . . . . . . 31
4 Environmental sources and sinks 33
4.1 Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.1.1 Partitioning between gas phase and particles . . . . . . . . . . . . . 34
4.1.2 Dry deposition of particles . . . . . . . . . . . . . . . . . . . . . . . . 36
iii
iv CONTENTS
4.1.3 Wet deposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.1.4 Chemical transformation in the atmosphere . . . . . . . . . . . . . . 41
4.2 Soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.2.1 The soil module in DEHM-POP . . . . . . . . . . . . . . . . . . . . 43
4.2.2 Air-soil exchange in DEHM-POP . . . . . . . . . . . . . . . . . . . . 44
4.2.3 Soil degradation in DEHM-POP . . . . . . . . . . . . . . . . . . . . 46
4.3 Ocean water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.3.1 Air-water gas exchange . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.3.2 Loss processes in the surface ocean compartment . . . . . . . . . . . 48
4.3.3 Oceanic transport of POPs . . . . . . . . . . . . . . . . . . . . . . . 49
4.4 Snow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.4.1 Air-snow exchange . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.4.2 Particles within the snowpack . . . . . . . . . . . . . . . . . . . . . . 56
4.4.3 Meltwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.4.4 Air-meltwater gas exchange . . . . . . . . . . . . . . . . . . . . . . . 57
4.4.5 Degradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.5 Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.5.1 Air-vegetation exchange . . . . . . . . . . . . . . . . . . . . . . . . . 58
4.5.2 Precipitation-vegetation exchange . . . . . . . . . . . . . . . . . . . 60
4.5.3 Influence of vegetation on soil . . . . . . . . . . . . . . . . . . . . . . 60
4.5.4 Degradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
4.6 Sea ice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
4.6.1 Sea ice in DEHM-POP . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.7 Other compartments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.7.1 Fresh water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.7.2 Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
4.7.3 Organic films in urban areas . . . . . . . . . . . . . . . . . . . . . . 63
5 Model input 65
5.1 Meteorological data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
5.2 Land use and topography data . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.3 Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
5.4 Initial environmental concentrations . . . . . . . . . . . . . . . . . . . . . . 68
5.4.1 Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
5.4.2 Soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
5.4.3 Ocean water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6 Model evaluation methods 73
6.1 Available measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6.1.1 Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6.1.2 Other media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.1.3 Extraction of data from the model simulations . . . . . . . . . . . . 78
6.2 Evaluation tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.2.1 Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
CONTENTS v
7 Results and model performance 81
7.1 Reference simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
7.1.1 Temporal trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
7.1.2 Seasonal patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
7.1.3 Particle-phase concentration . . . . . . . . . . . . . . . . . . . . . . . 86
7.1.4 Vertical distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
7.1.5 Surface compartment concentrations . . . . . . . . . . . . . . . . . . 88
7.2 Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
7.2.1 Long-term averages. . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
7.2.2 Source area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
7.2.3 IADN stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
7.2.4 Qu´ebec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
7.2.5 European stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
7.2.6 Stations in the Arctic . . . . . . . . . . . . . . . . . . . . . . . . . . 120
7.2.7 Vertical distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
7.3 Importance of the ocean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
7.3.1 R¨orvik . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
7.3.2 St´orh¨ofdi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
7.3.3 Alert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
7.4 Importance of the vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . 138
7.4.1 Source area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
7.4.2 Mid-latitude stations . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
7.4.3 Arctic stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
7.4.4 Previous model studies. . . . . . . . . . . . . . . . . . . . . . . . . . 142
7.5 Importance of the snowpack . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
7.5.1 The Arctic stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
7.5.2 North American and European stations . . . . . . . . . . . . . . . . 145
7.5.3 The role of the snowpack in the environmental cycling of α-HCH . . 147
7.6 Previous DEHM-POP results . . . . . . . . . . . . . . . . . . . . . . . . . . 151
7.7 Comparison with results from other models . . . . . . . . . . . . . . . . . . 151
7.8 Summary of the results and model performance . . . . . . . . . . . . . . . . 152
8 Applications of DEHM-POP 155
8.1 Transport episodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
8.2 Long-term simulation: 1945-2000 . . . . . . . . . . . . . . . . . . . . . . . . 159
9 Summary, conclusions
and future perspectives 167
9.1 Summary and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
9.2 Future perspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
10 Acknowledgements 171
Bibliography 173
A Paper I 189
vi CONTENTS
B Paper II 205
C Paper III 223
D Paper IV 233