National Long-Term Surveillance of Swiss Rivers

Verh. Internat. Verein. Limnol. 28 1101–1106 Stuttgart, July 2002

National long-term surveillance of Swiss rivers

A. Jakob, E. Binderheim-Bankay and J. S. Davis

Introduction Rhine (IKSR), the Global Environment Monitoring System – United Nations Environment Pro- The “National Long-term Surveillance of Swiss Riv- gram/World Health Organization (GEMS- ers” (NADUF) programme was initiated in 1972 as UNEP/WHO)). a cooperative project between three institutes: the The NADUF network of sampling stations Swiss Agency for the Environment, Forests and includes locations on all the major rivers of Switzer- Landscape (BUWAL), the Swiss Federal Institute for land. Chemical–physical data are collected at 19 sta- Environmental Science and Technology (EAWAG) tions (Fig. 1) selected to provide a representative and the Federal Office for Water and Geology overview of Swiss rivers. The locations include all (BWG). The program conducts the surveillance and rivers flowing out of Switzerland, the main tributar- evaluation of the chemical–physical state of Swiss ies to major lakes, and catchment areas at a range of rivers. altitudes extending from the Alps to the Swiss Pla- The goals of NADUF serve both national and teau. In addition, several heavily polluted river sec- international interests. The main national goal is to tions, of particular interest in water protection evaluate the effectiveness of water protection mea- efforts, are also sampled. The sampling modes sures. In addition, NADUF provides both basic data employed depend on the parameter group. Selected and sampling facilities for scientific studies on issues physical parameters are continuously measured with associated with river water. At the international level, electrodes. These parameters are: water level, tem- several NADUF stations serve as reference stations perature, electrical conductivity, pH and oxygen for other water surveillance programs (e.g. the Inter- concentration. Chemical parameters are measured national Commission for the Protection of the over 14-day periods, in samples continuously col-

Fig. 1. Locations of sampling stations of the NADUF program.

0368-0770/02/0028-1101 $ 1.50 ©2002 E. Schweizerbart’sche Verlagsbuchhandlung, D-70176 Stuttgart A. Jakob et al., Long-term surveillance of Swiss rivers 1102 lected on a discharge-proportional basis (BINDER- 1993, based on subsidies for specified ecological HEIM-BANKAY et al. 2000). These parameters include measures, defined in the agricultural law. total hardness, carbonate hardness, total suspended solids, calcium, potassium, sodium, magnesium, sul- The on-going reduction of water pollution, phate, silicic acid, chloride, ortho-phosphate, total based on the increase of infrastructure serving phosphorus, nitrate, total nitrogen, dissolved organic wastewater collection and treatment, could be carbon, total organic carbon, lead, copper, zinc, cad- documented by the NADUF data. The major mium, chromium and nickel. Since the beginning of contribution to this reduction had however NADUF, all chemical parameters have been mea- taken place before the initiation of the NADUF sured in the same laboratory, thus enabling a consis- project – 60% of the population was already tency in the data series. Though the basic set of parameters is given, there are degrees of flexibility for connected to wastewater treatment plants at the the sampling program: the length of the measuring time the program started. period and additional parameter possibilities are The positive effects of the measures men- determined individually for each station; these can tioned above are described below for two be adapted to special data needs for particular water NADUF stations. One station, Rhine at Basle, protection issues or for scientific research. represents a very large catchment area, on one of Europe’s largest rivers. The other station, Evaluating water protection measures at a Glatt at Rheinsfelden, represents a minor tribu- national level tary to the Rhine, north of Zurich. The Glatt, The NADUF databank, comprising almost 30 being heavily polluted at this location, is thus a years of surveillance in an extensive network of critical point to examine, and one at which the sampling stations, is an exceptional source of effects of water protection measures are readily information on the development of river water recognizable. The data obtained at these sta- quality throughout Switzerland. Evaluations tions are plotted in two different types of highlight a positive trend in the quality: with graphs. One represents a qualitative view, show- the exception of only a few rivers showing ing the development of the concentrations of marked pollution, all the main rivers in Switzer- the selected parameters. The other represents a land meet the criteria set by the water protec- quantitative view, in that the annual averages of tion ordinance. This can be seen as a successful the concentrations are shown in relation to the result of major endeavours for water protection respective annual discharges (JAKOB et al. 1994). that were undertaken throughout the country. Since concentration is influenced by discharge, In addition to documenting this general trend, a data evaluation looking at possible changes in the continuous surveillance program has been the amount of pollution benefits from compar- an effective instrument for the evaluation of ing concentrations occurring at similar those water protection measures that were initi- amounts of discharge. Using these evaluation ated during the course of investigation. For criteria, the following has been observed at the example, data evaluations clearly indicated a two stations: general decrease in phosphate. This arose from • The phosphate concentrations have signifi- the implementation of phosphate removal in cantly decreased since 1986. This is evident wastewater treatment plants, and from the both in graphs showing the development phosphate-ban initiated in 1986. In addition to along the time course (Fig. 2a, b), as well as such measures, which were implemented to in the discharge-related diagram (Fig. 3a, b). specifically benefit water, it could be seen that This trend is mainly due to the phosphate some additional measures, aimed at other envi- ban, together with the expanded capacity of ronmental problems, also led to benefits for wastewater treatment plants, and the water quality. Among documented cases of such increased infrastructure, connecting homes benefits were the use of the catalytic converter, and businesses to the treatment plants. The as of 1985, which led to a reduction in the use reduction in phosphate concentration was of leaded gasoline and reductions in nitrogen; ca. 50% on the Rhine at Basle, and ca. 80% financial support for organic farming, as of on the Glatt at Rheinsfelden. 1103 Verh. Internat. Verein. Limnol. 28 (2002)

2.0 0.3 Glatt a) Rhine b) Phosphate-ban for detergence Phosphate-ban for detergence 1986 1986 [mg P/l) 1.5 [mg P/l) 0.2

1.0

0.1 0.5

0.0 0.0 77 79 81 83 85 87 89 91 93 95 97 99 77 79 81 83 85 87 89 91 93 95 97 99

20 4.0 18 Glatt c) Rhine d) reduction of nitrous oxide emissions 16 [mg N/l) µg Pb/l) [ 3.0 of motorised traffic 14 12 10 2.0 8 6 1.0 4 2 new agricultural law 1993 0 0.0 77 79 81 83 85 87 89 91 93 95 97 99 77 79 81 83 85 87 89 91 93 95 97 99

Fig. 2. Development of phosphate and nitrate concentrations in the Rhine at Basle (b and d) and of phosphate and lead concentrations in the Glatt at Rheinsfelden (a and c). The thin line represents the 14-day continuously collected, discharge-proportional samples. The thicker line shows the discharge weighted annual averages. The phosphate ban had an immediate influence on the phosphate concentration in water; in contrast, the reduced lead and nitrogen emissions from motorised traffic have only gradually influenced the concentrations of these substances in water.

• The lead concentrations have decreased sig- The development of the nitrate concentration nificantly since 1989. This is seen both in shows an increasing trend through the 1980s the graph representing the development of and a decreasing trend during the 1990s. The concentration over time (Fig. 2c), and in the maxima occurred between 1986 and 1993 discharge related graph (Fig. 3c). This (Fig. 2d). The same pattern is seen in the dis- reduction is considered the result of the charge related graph (Fig. 3d). These changes decrease in use of leaded gasoline, an effect are possibly due to the intensification in agri- stemming from the introduction of catalytic cultural methods before 1993, followed by the converters. According to the BUWAL adoption of measures furthering a more ecolog- (1997), the lead emission from traffic ically oriented agriculture. There is however decreased ca. 90% between the early 1970s most likely an additional factor contributing to and 1996. The reduction in lead concentra- the decrease in nitrate in water: as of the late tion is particularly marked in the Glatt, 1980s there has been a decrease in nitrogen reflecting the high proportion (24%) of emissions from vehicles. This resulted in densely populated land in the catchment reduced deposition, and thus a lower nitrate area. loading of waters. According to information A. Jakob et al., Long-term surveillance of Swiss rivers 1104

0.12 [mg P/l] Glatt a)[mg P/l] Rhine b) 0.8 77 79 80 77 0.10 82 79 78 81 85 83 80 0.6 83 81 0.08 84 85 82 84 86 0.06 0.4 91 90 86 92 88 87 0.04 89 93 94 0.2 89 88 96 96 9890 0.02 98 95 87 95 97 91 92 94 99 97 0.0 93 0.00 56789101112800 900 1000 1100 1200 1300 1400 1500 average discharge [m³/s] average discharge [m³/s]

7 1.9 [µg Pb/l] Glatt c)[mg N/l] Rhine d) 89 92 6 88 1.8 90 88 85 91 86 79 1.7 5 77 93 86 89 94 1.6 87 87 96 84 4 80 81 92 1.5 82 85 83 95 95 3 84 79 1.4 97 98 83 77 91 82 97 93 94 78 2 1.3 80 96 99 81 98 1 1.2 56789101112800 900 1000 1100 1200 1300 1400 1500 average discharge [m³/s] average discharge [m³/s]

Fig. 3. Discharge weighted annual averages of concentrations, plotted in relation to discharge. The graph shows phosphate and nitrate for the Rhine station at Basle (b and d), and phosphate and lead for the Glatt station at Rheinsfelden (a and c). The phosphate and lead concentrations are considerably lower after 1986 (1989 for lead; the data points in both cases are marked). The nitrate concentrations clearly show a maximum between 1986 and 1989 (data points marked). from the BUWAL (2000), since the end of the (www.bwg.admin.ch). This accessibility sup- 1980s there was a general decrease in nitrogen ports the cooperation and coordination with deposition from a variety of sources, including those in official positions associated with water trans-border sources. The maximum nitrate protection, with other monitoring programs concentrations on the Rhine at Basle were and in research institutes. approximately 20–30% higher than the values observed before 1986 and after 1993 (Fig. 3d). Significance of NADUF at an international The same picture is seen for the nitrate values level in the Glatt at Rheinsfelden, except that here, due to the high proportion of waste water, the NADUF participates in various international reduction was only 10–20%. monitoring programs, in that several of its sta- The NADUF data, which provide a signifi- tions also serve for the sampling in other net- cant base for the evaluation of water protection works (e.g. IKSR). The NADUF stations, measures, are made generally available in two particularly in the alpine region, represent a low ways – they are published in the Hydrological level of anthropogenic pollution. Data from Yearbook and they are accessible on the Internet them thus serve as reference values for ‘natural’ 1105 Verh. Internat. Verein. Limnol. 28 (2002) water. The case of the Rhine clearly illustrates The following are examples of points to be consid- how the quality of this river changes along its ered in making decisions for the program’s future, in path from Lake Constance to the North Sea. In particular as reflects parameter selection: recent years the concentrations of heavy metals, • The measurement of the nutrients (nitrogen and phosphate) provides a critical evaluation basis for upon reaching the North Sea, have been 4–10 the effectiveness of wastewater treatment plants, times higher than they are at Lake Constance. and of the ecological measures to be imple- The nitrate concentrations were three times mented in agriculture. higher (IKSR). The NADUF station Rhein- • The presence of synthetically produced organic Rekingen serves as the reference station. The substances in water is being increasingly recog- station in Basle measures the total load coming nized as a significant problem. Some of these from Switzerland via the Rhine. substances can have adverse effects at extremely low concentrations, making both detection and Among the international organizations, there removal difficult. Among the wide spectrum of is an intensive exchange of data and under- effects being detected, their endocrine-like standing. The long-term data series of NADUF behaviour has been of particular concern. play a particularly critical role in the detection Detecting and measuring such substances is an and evaluation of trends in those rivers that immediate task for water quality work. The sam- cross borders. As a result of this international pling and analytical infrastructure of NADUF cooperation, the NADUF data can contribute provides a functional basis for cooperation with research projects on the occurrence and behav- not only to European environmental reports iour of these substances in water. Such data are (European Environmental Agency, EUA), but pertinent for the development of measures to also to reports in other parts of the world (Glo- reduce both the occurrence and use of these crit- bal Environment Monitoring System – United ical pollutants. Nations Environment Program/World Health • Water quality is endangered not only by pollut- Organization (GEMS-UNEP/WHO), Organi- ants, but also by physical intervention, including zation for Economic Cooperation and Devel- channelling, which affects the banks and beds of rivers and streams. The protection of waterways opment (OECD)). to conserve both the quality of water itself, as well as the landscape, is gaining recognition; Conclusions and project outlook renaturation and revitalization projects are being The NADUF program, whether in national or inter- initiated. The measurement of nutrients helps in national structures, serves both the practical level, the adherence to the improvement in the self- such as the evaluation of the effectiveness of water purification of the waters, resulting from these protection measures, and the scientific research level, measures. This in turn aids in the identification as in studies on reactions and processes occurring in of other catchment areas that could benefit from river water. Both levels are essential for interpreting such measures. data on water quality and for the planning and eval- • Climate issues are becoming increasingly impor- uation of water protection measures. tant. Measurements of temperature and geo- Maintaining the success of this program requires chemical parameters can help provide more periodic evaluation and adaptation at various levels, insight into the consequences of changes in in particular concerning the selection of parameters, weather, temperature and precipitation patterns sampling modes at different locations, cooperative for surface waters. research projects and access to data. The critical tasks In order to effectively utilize the data that will be of parameter selection include the following aspects: obtained in future NADUF work, the following two the relevance of continuity for individual parame- structural points are of major help. They have con- ters, identification of those pollutants that remain of tributed significantly to the insights gained from the significance and should thus stay in the program, NADUF program. recognition of potentially polluting substances, • Long-term database: which should be included for future measurements, This is essential for both the detection and inter- cooperative research projects, which can help pro- pretation of changes in the concentration and vide information on the distribution and behaviour behaviour of substances in water systems. A of substances in water, utilization of the data to serve long-term databank provides the basis for com- the development of new water protection criteria parative evaluations, which draw upon observa- and legal measures. tions from similar hydrological conditions in A. Jakob et al., Long-term surveillance of Swiss rivers 1106

other years. In doing so, it enables the essential Acknowledgments differentiation between ‘real’ changes in concentration and/or load, and those mainly reflecting This publication would not have been possible with- fluctuations in discharge and temperature. out reliable contributions and supportive coopera- • Utilizing complementary information in tion in field work, laboratory analysis, data manage- parameter selection: ment and data evaluation. The authors express their An appropriate evaluation of concentration appreciation to all the colleagues associated with the changes in water quality indicators often project at the BWG, EAWAG and BUWAL. depends on measurements of accompanying substances of natural origin. These, e.g. mainly References geochemical parameters, can provide pertinent BINDERHEIM-BANKAY, E., JAKOB, A. & LIECHTI, P., 2000: information on the sources, both of the pollut- NADUF - Messresultate 1977–1998. – Schriftenreihe ant (e.g. from agriculture or wastewater treat- Umwelt Nr. 319, Bern, 241pp. ment plant) and of the water itself (e.g. run-off, BUWAL, Bundesamt für Umwelt Wald und Landschaft, ground water, glacial and snow water). 1997: NABEL Luftbelastung 1996. – Schriftenreihe Umwelt Complementary information contributes to the Nr. 286, Bern. overall success of monitoring programs in two BUWAL, Bundesamt für Umwelt Wald und Landschaft, main ways: by aiding data validation, and thus 2000: NABEL Luftbelastung 1999. – Schriftenreihe Umwelt also evaluation and interpretation, and by pro- Nr. 316, Bern. viding data that serve as basic links to other IKSR, Numerical Tables of the International Commission for water studies. This in turn enables comparative the Protection of the Rhine (published annually). evaluations for research work on the development of water protection measures and the eval- JAKOB, A., ZOBRIST, J., DAVIS, J. S., LIECHTI, P. & SIGG, L., uation of their effectiveness. 1994: NADUF – Langzeitbeobachtung des chemisch-phys- ikalischen Gewässerzustandes. – Gas Wasser Abwasser 3/94: 171–186. Summary NADUF is a major long-term study on the water Authors’ addresses: quality of Swiss rivers. Within the NADUF pro- A. JAKOB, Federal Office for Water and Geology, CH- gram, the chemical–physical state of the main Swiss 3003 Bern, Switzerland. rivers has been measured since 1972. NADUF serves E-mail: [email protected] two main purposes: to evaluate the effectiveness of E. BINDERHEIM-BANKAY, Sponsolim Umweltconsult- water-protection measures and to provide data for scientific studies on biological, chemical and physi- ing, Zürichweg 5, CH-8153 Rümlang, Switzerland. cal processes occurring in river water. The data and E-mail: [email protected] evaluations made available by the NADUF work J. S. DAVIS, Bergliweg 12, CH-8304 Wallisellen, have relevance for national as well as international Switzerland. studies. E-mail: [email protected]