4. Monitoring programmes - 4.1. Chem. and phys.

4. Monitoring programmes

In the following chapter the monitoring programmes mentioned in the previous chapter are categorised according to the waterbody (ie. rivers, lakes, coastal areas and open marine areas) and the variables measured, respectively. Similar monitoring programmes are put together and similarities and differences according to network set-up, sampling frequency and variables measured are analyzed. The monitoring programmes have been categorised into the following main groups:

• Chemical and physical assessment of river water quality
• Biological assessment of river quality
• Chemical and physical assessment of lake water quality
• Biological assessment of lake quality
• Acidification of inland surface waters
• Chemical and physical assessment of marine water quality
• Biological assessment of marine quality
• Monitoring of organic micropollutants, radioactivity and microbiological indicators.

4.1 Chemical and physical assessment of river water quality

Nearly all the countries in the EEA area have a national monitoring programme with the purpose of assessing the chemical and physical water quality of rivers. Additionally some international programmes, such as the EU river network (pursuant to the Council Decision 77/795/EEC) and the OECD and GEMS/WATER networks, focus on the chemical and physical water quality in primarily large rivers. Some countries have a long tradition for national coordination of their river water quality monitoring programmes. Finland and Spain, for instance, initiated their national monitoring activities in the early 1960s. Most of the other countries also have a long tradition for monitoring the chemical quality of river water, however, this has traditionally been performed by regional or local institutions. During the 1980s the growing need for national river water quality information made these countries initiate national monitoring programmes. In most cases these river monitoring programmes are based on the information collected by regional organizations.

In Table 4.1.1 37 monitoring programmes with the purpose of chemical and physical assessment of river water quality are listed. For each country is first listed the main national monitoring programme (generally assigned the code 'R1'), but also more specific monitoring programmes such as, for instance, monitoring of transboundary rivers and networks assigned to estimate loading of coastal areas have been included in the table.

Table 4.1.1: Monitoring programmes with the purpose of chemical and physical assessment of river water quality. The code of the monitoring programme refers to the country and the numbers assigned to the monitoring programme in chapter 3. Sampling frequency is the most frequent.

X: no specific information, V: varying, C: continuous.

River monitoring networks

The river monitoring networks can be divided into three categories according to their main purpose:

1. general characterization of rivers and streams in a country,
2. monitoring of water quality of rivers draining specific areas such as, for instance, reference sites in forested or uncultivated areas, or leaching of substances from agricultural watersheds, and
3. networks designed to estimate the riverine loading from land into coastal areas, or the loading by transboundary rivers from one country to the neighbouring country.

Many monitoring networks are multi-purpose and may be assigned to more than one category. The results from a network may, for instance, be used both to make a general characterization of river water quality and to estimate the nutrient loading of coastal areas. In Table 4.1.2 the various monitoring networks have been categorized according to their main purposes:

Table 4.1.2: Characterization of chemical and physical river water quality monitoring networks according to their purpose. Code refers to country plus programme number (see Table 1.2 for country code and chapter 3 for programme number).

General characterization of river water quality

Twenty monitoring programmes have networks specifically designed to elaborate a general characterization of rivers and streams in a country. Most of these networks are based on more than 100 sampling sites located in all major river systems and rivers in a country (Table 4.1.3). The area density of sampling sites varies from one sampling site per 10,000 km² to more than five sampling sites per 1,000 km²; 1-2 sampling sites per 2,000 km² sites generally being found. The number of sampling sites per million inhabitants vary between 2 and 50. In many of the monitoring networks (eg. the British UK-R2), several sampling sites are located along the main course of the major rivers. In the Spanish network (ES-R1) around 10 sampling sites are situated along the main course of the eight major rivers, while only one sampling site is found at less important rivers. In the Danish (DK-R1) and the British network (UK-R1) there is only one sampling per river.

Table 4.1.3: National river monitoring programmes for general chemical and physical assessment of river water quality. "Rivers" is the total number of named rivers sampled. "River systems" is rivers discharging from the country either into coastal areas or into neighbouring countries.

C: Continuous measurements

According to most of these programmes, samples are taken annually with a sampling frequency ranging from 4 to 26 annual samples. The number of variables measured vary from 4 to 120, but all programmes generally include determination of basic variables (eg. pH, conductivity, water temperature, etc.), organic pollution indicators (eg. dissolved oxygen, BOD, etc.), nutrients and suspended solids. Many programmes also include determination of specific ions (eg. chloride, sulphate, calcium, etc.) and heavy metals. Additionally, determination of more specific contaminants such as organic micropollutants and radionuclides is included in some monitoring programmes.

Monitoring of small catchments

In the Nordic countries, ie. Denmark, Finland, Norway and Sweden, there are monitoring networks with the purpose of monitoring water quality and loading from specific catchments. These monitoring networks generally consist of up to 20 relatively small stream catchments and involve detailed integrated studies of both river water quality and of the catchment (eg. land use, soil type, etc.). The main purposes are to follow reference areas, loading from agricultural land or impact of acid precipitation.

Riverine loading to coastal areas or loading by transboundary rivers

Many monitoring networks are established with the purpose of estimating the riverine loading from land areas into coastal areas or loading by transboundary rivers. Generally these networks consist of sampling sites located downstream all major river systems. Countries having a long coastline compared to their area, examples being the United Kingdom, Ireland, Norway, Sweden, Denmark and Greece, generally have a large number of relatively small river systems. Consequently, the number of sampling sites needed to estimate the input to coastal areas is high, whereas few sampling sites in countries dominated by a few large river systems provide a fair estimate of the riverine loading to coastal areas. In Denmark, for instance, sampling undertaken in 124 rivers systems only results in direct measurement of the loading from around 60 per cent of the land area into coastal areas, while sampling undertaken downstream the eight largest Spanish rivers includes approximately 75 per cent of the loading from the Spanish land area. The analysis programmes generally include determination of nutrients and suspended matter. Additionally, loading by heavy metals and organic micropollutants may be measured. The sampling frequency is typically monthly or even more frequently.

Variables measured

In total more than 150 different variables are measured in the various monitoring programmes. In the following evaluation of similarities and differences between the monitoring programmes attention has been directed at the most frequently measured variables.

The number of variables measured in the various monitoring programmes vary from 4 to 120 variables (Table 4.1.4). In 70 per cent of the monitoring programmes less than 40 variables are measured.

Table 4.1.4: Typical number of variables measured in number of river monitoring programmes and (percentage). Total 30 river monitoring programmes.

The chemical and physical variables measured in river water have been categorized according to the information obtained on the basis of the variables determined (Table 4.1.5).

Table 4.1.5: Main groups to which the analytical variables have been assigned. Mnemonic codes used in report are given in parenthesis. Only the main variables are shown.

In the following sections, the various categories of variables measured are evaluated.

Basic variables

In nearly all of the monitoring programmes basic physical and chemical variables, such as water flow (Q), water temperature (TEMPW), pH (PH), conductivity (COND), and dissolved oxygen (OX), are measured (Table 4.1.6). Additionally, some monitoring programmes include measurement of turbidity (TURB) and colour (CNR) as well. The four most frequently measured variables, ie. TEMPW, PH, COND and OX, are all included in 20 of the monitoring programmes (ie. 65 per cent). The sampling frequency of these basic variables varies from continuous registration of TEMPW, PH, COND and OX in the Rhine and continuous registration of water height (water flow) in many programmes to, typically, monthly or more frequent measurements in the majority of the other programmes.

Table 4.1.6: Basic variables determined in river chemical and physical water quality monitoring programmes. For each monitoring programme the number of annual samples are listed.

C: Continuous registration; X: Unknown or varying sampling frequency.

Suspended particulate matter

Summary variables characterizing the content of suspended particulate matter are measured in most of the river monitoring programmes either as suspended particulate matter (SM), turbidity (TURB), biochemical oxygen demand (BOD), chemical oxygen demand (COD) or total organic carbon (TOC). The analysis programmes generally include more than one of these variables, but the variables omitted differ. SM, BOD, and COD are measured in 10-12 of the 15 countries; SM is not measured in Germany, Denmark and Ireland; BOD is not measured in Norway, Sweden and Greece; and COD is not measured in Germany, Ireland, Luxembourg, the UK and Sweden. The sampling frequency of these variables exceeds six annual samples in nearly all monitoring programmes, and samples are typically taken at monthly intervals.

Table 4.1.7: Suspended particulate matter measured in river chemical and physical water quality monitoring programmes. Dissolved organic carbon (DOC) has also been included in the table.

* Only at 2 sites

Organic pollution indicators

There is a long tradition for measurement of organic pollution indicators in many European countries, indicators of organic pollution being included in more than 80 per cent of the river monitoring programmes. Generally, the monitoring programmes include dissolved oxygen (OX), biochemical oxygen demand (BOD), chemical oxygen demand (COD), and ammoniacal nitrogen (NH4N). Denmark, Norway and Sweden do not measure dissolved oxygen. In some countries either BOD or COD is measured; traditionally the Nordic countries have only measured COD, while only BOD has been measured in the UK and Ireland. Especially as to BOD many different analytical methods are used. The sampling frequency is generally monthly.

Table 4.1.8 : Organic pollution indicators determined in river chemical and physical water quality monitoring programmes. For each monitoring programme the number of annual samples are listed.

* Only at 2 sites

Eutrophication - Nutrients

Eutrophication is a wide-spread problem and measurement of nutrients have therefore been included in many river monitoring programmes. Most programmes include measurement of both phosphorus and nitrogen. Total phosphorus (PTOT) is measured in 27 of the monitoring programmes, while dissolved reactive phosphate (PO4P) is measured in 28 programmes. Total and Kjeldahl nitrogen (NTOT) are measured in 15 of the monitoring programmes, while oxidized nitrogen (NO23N), mainly nitrate, and ammoniacal nitrogen are measured in 30 and 29 of the monitoring programmes, respectively. In all 15 countries PO4P, NO23N and NH4N are measured, while PTOT and NTOT are measured in 13 and 7 countries, respectively. measurement of nutrients is generally undertaken at monthly intervals.

Table 4.1.9: Nutrients determined in river chemical and physical water quality monitoring programmes. For each monitoring programme the number of annual samples are listed.

* Only at 2 sites

Specific major ions

Measurement of several specific major ions is used to characterize river water quality. The most frequently measured ions are listed in Table 4.1.10. The four major cations, ie. calcium (CA), magnesium (MG), potassium (K), sodium (NA) as well as two of the major anions, ie. chloride (CL) and sulphate (SO4), are measured in about two thirds of the monitoring programmes, while the anions carbonate (CO3) and bicarbonate (HCO3) are not included in the analysis programme. Minor halides, such as fluoride (F), bromine, iodine, and boron, are only included in a few river monitoring programmes. Additionally, only few monitoring programmes involve measurement of silica (SIO2), arsenic (AS) and cyanide (CN). The specific major ions are generally measured at monthly intervals.

Table 4.1.10: Specific major ions determined in river chemical and physical water quality monitoring programmes. For each monitoring programme the number of annual samples are listed.

* Only at 2 sites

Metals

Analysis of metals is performed in about 40 per cent of the river monitoring programme. However, in many of the programmes metals are only measured at selected sampling sites, primarily major rivers or rivers suspected to be contaminated by heavy metals. In two monitoring programmes (BE-R1 and GR-R2) the specific metals have not been specified. In Denmark only analysis of iron is included in national river monitoring programmes. The most frequently measured heavy metals are cadmium (CD), mercury (HG), copper (CU), zinc (ZN) and lead (PB), each measured in more than 17 of the monitoring programmes and in about 13 of the 15 countries. Aluminium (AL) is studied in countries with acidification problems. In some monitoring programmes analysis of manganese (MN), nickel (NI) and iron (FE) is also included. The sampling frequency varies from a few annual samples to monthly samples in half of the monitoring programmes.

Table 4.1.11: Metals determined in river chemical and physical water quality monitoring programmes. For each monitoring programme the number of annual samples are listed.

* Only at 2 sites; # 6-52, most often 13.