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Garmo , Øyvind A.; Skjelkvåle, Brit Lisa; de Wit, Heleen A.; Colombo, Luca;
Curtis, Chris; Fölster, Jens; Hoffmann, Andreas; Hruška , Jakub; Høgåsen,
Tore; Jeffries, Dean S.; Keller, W. Bill; Krám, Pavel; Majer, Vladimir; Monteith,
Don T.; Paterson, Andrew M.; Rogora, Michela; Rzychon, Dorota;
Steingruber, Sandra; Stoddard, John L.; Vuorenmaa, Jussi; Worsztynowicz,
Adam. 2014. Trends in surface water chemistry in acidified areas in
Europe and North America from 1990 to 2008. Water, Air, and Soil
Pollution, 225 (3), 1880. 14, pp. 10.1007/s11270-014-1880-6
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1
Trends in Surface Water Chemistry in Acidified Areas in
Europe and North America from 1990 to 2008
Øyvind A. Garmo*
1
, Brit Lisa Skjelkvåle
1
, Heleen A. de Wit
1
, Luca Colombo
2
, Chris Curtis
3
,
Jens Fölster
4
, Andreas Hoffmann
5
, Jakub Hruška
6, 7
, Tore Høgåsen
1
, Dean S. Jeffries
8
, W.
(Bill) Keller
9
, Pavel Krám
6
, Vladimir Majer
6
, Don T. Monteith
10
, Andrew M. Paterson
11
,
Michela Rogora
12
, Dorota Rzychon
13
, Sandra Steingruber
14
, John L. Stoddard
15
, Jussi
Vuorenmaa
16
, Adam Worsztynowicz
13
1
Norwegian Institute for Water Research, Oslo, Norway
2
University of Applied Sciences of Southern Switzerland, Canobbio, Switzerland
3
GAES, University of the Witwatersrand, Johannesburg, South Africa
4
Swedish University of Agricultural Sciences, Uppsala, Sweden
5
Umweltbundesamt, Dessau, Germany
6
Czech Geological Survey, Prague, Czech Republic
7
Global Change Research Centre, Academy of Sciences of the Czech Republic, Brno, Czech
Republic
8
National Water Research Institute, Burlington, ON, Canada
9
Laurentian University, Sudbury, ON, Canada
10
NERC Centre for Ecology & Hydrology, Lancaster Environment Centre, United Kingdom
11
Ontario Ministry of Environment, Dorset, ON, Canada
12
CNR Institute of Ecosystem Study, Verbania Pallanza, Italy
13
Institute for Ecology of Industrial Areas, Katowice, Poland
14
Ufficio aria, clima e energie rinnovabili, Bellinzona, Switzerland
15
US Environmental Protection Agency, Corvallis, OR, USA
16
Finnish Environment Institute, Helsinki, Finland
*Corresponding author. Contact details:
Norwegian Institute for Water Research (NIVA)
Sandvikaveien 59, N-2312 Ottestad, Norway
Telephone. (+47) 91724722, Fax. (+47) 62576653
Email. oga@niva.no
Manuscript
Click here to download Manuscript: Trends in surface water chemistry; revised.doc
Click here to view linked References
2
Abstract
1
Acidification of lakes and rivers is still an environmental concern despite reduced emissions of
2
acidifying compounds. We analysed trends in surface water chemistry of 173 acid-sensitive sites from
3
12 regions in Europe and North America. In 11 of 12 regions, non-marine sulphate (SO
4
*) declined
4
significantly between 1990 and 2008 (-15% to -59%). In contrast, regional and temporal trends in
5
nitrate were smaller and less uniform. In 11 of 12 regions, chemical recovery was demonstrated in the
6
form of positive trends in pH and/or alkalinity and/or acid neutralizing capacity (ANC). The positive
7
trends in these indicators of chemical recovery were regionally and temporally less distinct than the
8
decline in SO
4
*, and tended to flatten after 1999. From an ecological perspective, the chemical quality
9
of surface waters in acid-sensitive areas in these regions has clearly improved as a consequence of
10
emission abatement strategies, paving the way for some biological recovery.
11
12
13
14
Keywords: acid deposition; surface waters; trend analysis; monitoring network; chemical recovery
15
16
17
18
3
1. Introduction
19
Over the past 30 years, acid has
20
received considerable attention as an international environmental problem in Europe and
21
North America (Likens et al. 1979). Polluted air masses containing sulphur and nitrogen
22
compounds travel long distances across national boundaries. Acidifying compounds thus
23
affect surface waters, groundwaters and acid sensitive soils far beyond their country of origin.
24
Acidification of the environment has lead to fish death and extinction of fish populations
25
(Haines and Baker 1986), soil acidification (Matzner and Murach 1995), and reduced forest
26
vitality (Fischer et al. 2007). Recently, deposition of reactive nitrogen has also been shown to
27
pose a threat to remote terrestrial and aquatic ecosystems through nutrient enrichment (Lepori
28
and Keck 2012; Stevens et al. 2011; Phoenix et al. 2012).
29
The Convention on Long-Range Transboundary Air Pollution (CLRTAP) came into effect in
30
1983 to control air pollutant emissions in Europe and North America, and thereby improve
31
the environmental status of natural ecosystems. Under the CLTRAP, international cooperative
32
monitoring programmes were initiated to assess the impact of atmospheric pollution on
33
ecosystems. For surface waters, the International Cooperative Programme on Assessment and
34
Monitoring Effects of Air Pollution on Rivers and Lakes (ICP Waters) has been an important
35
contributor documenting the effects of the implemented Protocols under CLRTAP since 1985
36
(Kvaeven et al. 2001).
37
The ICP Waters programme is designed to assess, on a regional basis, the degree and
38
geographical extent of acidification of surface waters. The collected data provide information
39
on dose/response relationships for a wide range of acid-sensitive lakes and streams under
40
varying deposition regimes by correlating changes in acidic deposition with the physical,
41
chemical and biological status of lakes and rivers. Data collected by various monitoring
42
schemes are integrated and interpreted, and inter-laboratory quality control systems are run to
43
ensure data are comparable across participating countries. Previous trend analyses of ICP
44
Waters data on surface water chemistry have provided important indications of the geographic
45
extent of acidification and recovery of lakes and streams for the 1980s (Newell and Skjelkvåle
46
1997), the 1980s and 1990s (Stoddard et al. 1999), and up to the start of 2000 (Skjelkvåle et
47
al. 2005; Skjelkvåle et al. 2001). Early assessments provided little evidence for chemical
48
recovery during the 1980s. Subsequently, however, patterns of widespread chemical recovery
49
4
became clear during the 1990s, as indicated by reduced sulphate (SO
4
) concentrations and
50
increases in pH and alkalinity. The reduction in sulphur deposition is considered to be the
51
main driver of the improved acidification status of surface waters and is also substantiated by
52
catchment input output budgets (Prechtel et al. 2001) and acidification models (Jenkins et
53
al. 2003).
54
Whether continued reduction in emissions of sulphur and nitrogen will lead to further
55
improvement of surface water quality in acid-sensitive regions, sufficient to sustain biological
56
recovery, depends on a number of factors (Wright et al. 2005). In some regions, base cations
57
have declined at a similar or greater rate than SO
4
, preventing chemical recovery (Skjelkvåle
58
et al. 2005; Stoddard et al. 1999). Catchments continue to be enriched by nitrogen deposition
59
with possible consequences for enhanced leaching of nitrate (NO
3
) (Curtis et al. 2005;
60
Moldan et al. 2006; Oulehle et al. 2008; Stoddard et al. 2001), especially under climate
61
change. Additionally, widespread increases in concentrations of dissolved organic carbon
62
(DOC) have also been documented and related to changes in atmospheric chemistry, most
63
prominently the decline in sulphur deposition (Monteith et al. 2007). The increase in DOC
64
may dampen expected reductions in acidity as humic substances are naturally acidifying
65
agents (Erlandsson et al. 2011). Thus, ground truth data on the environmental status and
66
recovery of acid-sensitive surface waters remain important for assessing the effects of
67
emission controls.
68
Here, we report trends in key variables of surface water chemistry from 173 monitoring sites
69
from 1990 to 2008. Trends for individual sites, as well as aggregated trends by regions are
70
presented.
71
2. Methods
72
2.1 Selection of variables
73
The analysis of surface water response to changing deposition comprises variables that are
74
sensitive to acidification and recovery:
75
Non-marine SO
4
and NO
3
are strong acid anions. As ICP Waters sites are selected to
76
be remote from the influence of direct terrestrial pollution, elevated concentrations
77
largely reflect the combined effects of recent trends in deposition and ecosystem
78
