Overview of the drinking water quality in Europe. Results of the reporting under the Drinking Water Directive 98/83/EC

Transcription

1 Overview of the drinking water quality in Europe Results of the reporting under the Drinking Water Directive 98/83/EC

2 Contents 1 Introduction Legislation Drinking water quality parameters Water Supply Zones and information to the public European results General information Drinking water quality Causes of non-compliance Country comparison Measures to improve drinking water quality European drinking water quality

3 1 Introduction 1.1 Legislation The Drinking Water Directive (98/83/EC) aims to ensure that water intended for human consumption is safe. It must be free of any microorganisms, parasite or substance that could potentially endanger human health. It applies to all water intended for human consumption apart from natural mineral waters and waters which are medicinal products. The Directive came into force in 1998 and replaced the Directive 80/778/EEC. All 27 Member States of the EU have transposed the Directive in their national legislation (transposition) and they have to comply with the requirements of the Directive (implementation). The Directive: Sets quality standards for drinking water quality at the tap (microbiological, chemical and organoleptic parameters) and the general obligation that drinking water must be wholesome and clean, Obliges Member States to regular monitoring of drinking water quality, to take remedial action in case the monitoring reveals problems and to provide to consumers adequate and upto-date information on their drinking water quality. Allows Member States to exempt water supplies serving less than 50 persons or providing less than 10 m³ of drinking water per day as an average and water in foodprocessing undertakings where the quality of water cannot affect the wholesomeness of the foodstuff in its finished form. 1.2 Drinking water quality parameters The Directive sets standards for the most common organisms and substances that can be found in drinking water. In the Directive a total of 48 parameters must be monitored and tested regularly. In general, WHO guidelines for drinking water and the opinion of the Commission's Scientific Advisory Committee are used as a basis for the standards in the Directive. According to Annex I of the Directive, the parameters are divided into microbiological parameters, chemical parameters, indicator parameters, and radioactivity. The two microbiological parameters Escherichia coli and Enterococci have a parametric value that is a substitute for zero, in other words these parameters should be absent from drinking water to guarantee its quality. The indicator parameters, including some microbiological indicator parameters, have been decided upon not for their direct relevance to the quality of water, but to indicate that something has changed in the source water, the treatment or the distribution of the water. This needs to be investigated and when urgent needs to be adjusted. Even though most indicator parameters do not pose a direct threat to human health, they might impact indirectly through the appearance, taste or odour of the water (and impact on the acceptability by the consumer) or they might interfere with proper treatment e.g. inadequate disinfection through presence of organic matter. The chemical parameters are selected for their potential impact on human health. Chemical parameters are besides accidents almost never present in drinking water in concentrations that cause acute health effects. Furthermore the impact of any exceedance or non-compliance of chemicals depends on the way they affect the human body. Mostly the parametric values are based on lifelong European drinking water quality

4 exposure and an average drinking water intake of two liters per person per day. Here a distinction between threshold and non-threshold substances occurred: In the case of threshold chemicals there will be no impact on human health when the concentrations are below the threshold. In the case of non-compliance the impact depends on the level of non-compliance, the duration of exposure and the safety factor that has been used in setting the parametric value. This differs per parameter, based not only on health impacts, but also on technological capability and analytical possibilities. In case of non-thresholds chemicals such as pesticides there is no threshold below which there is no potential effect on human health. Here a risk approach is used that mostly accepts one additional death through drinking water in one million people; this is more strict than the value currently used by WHO (1 in people). When the level of non-compliance and the duration is known, it is then possible to try to estimate the potential impact on human health in a particular Member State or water supply zone (Hulsmann et al. 2015). Member States may, for a limited time deviate from chemical quality standards specified in Annex I. This process is called "derogation". Derogations can be granted, provided it does not constitute a potential danger to human health and provided that the supply of water intended for human consumption in the area concerned cannot be maintained by any other reasonable means. The drinking water quality must be validate from locations that are representative of the water source, treatment plant, storage facilities, distribution network, points at which water is delivered to the consumer, and points of use. So, the localization of the water abstraction point depends on the water quality parameter and the potential risk, e.g. in most cases exceedances of lead caused by domestic pipe system and lead is not a problem in waterworks, therefore, all the more important to sample lead at the tap after distribution network. 1.3 Water Supply Zones and information to the public Development of the drinking water quality is based on the spatial scale of a water supply zone. A water supply zone is defined as a geographically defined area within which water intended for human consumption comes from one or more sources and within which water quality may be considered as being approximately uniform. (Annex II, DWD). This means, a water supply zone could be a waterworks, where raw water from e.g. two drinking water dams is collected and processed; or it could also be an elevated tank, of which a district is supplied with drinking water. The Directive makes a distinction between large and small water supply zones. Large water supply zones supplying more than 1,000 m³ drinking water per day as an average or serving more than 5,000 persons. Small water supply zones are subdivided into three more categories: category 1: supplying 10m³ to 100m³/day; category 2: supplying 100m³ to 400m³/day and category 3: supplying 400m³ to 1,000m³/day. Minimum water quality requirements are equal for both large and small supplies. However, monitoring requirements differ and the reporting obligation to the European Commission is mandatory for the large water supply zones, but Member States are obliged to report also water quality of small water supply zones, if data are available. Every three years Member States must report the results on the drinking water quality to European Commission digitally. They are also obliged to publish a national report to the public. In Table 1-1, the links to the given national drinking water quality reports of the reporting period 2011 to 2013 are listed. Member States country reports show results of the drinking water quality in the reporting period 2011 to 2013 in a nutshell, and the reported data are made available within WISE databases. 4 European drinking water quality

5 Table 1-1 Links to national drinking water reports ( ). MS AT BE BG CY CZ DE DK EE ES FI FR GR HU IE IT LT LU LV MT NL PL PT RO SE SI SK UK Member State (MS) report location pdf _1_ausnahmen_ueberblick_2012_-_wva_klein.pdf _2_ausnahmen_2013_neu_- wva_klein.pdf _1_liste_wva_gross_2013.pdf (VLA) (WLA) (BRUS) &Expand=1&Seq= pdf/manage_document %202012_tcm pdf European drinking water quality

6 2 European results 2.1 General information In Europe, the mean water consumption per inhabitant and day is about 200 liters and differs between Member States (e.g. Slowakia: 81 l; Denmark, Belgium, Hungary: < 150 l; Ireland, United Kingdom, Portugal, Lithuania, Finland: > 200 l). This water derives from different sources, mainly groundwater or surface water (e.g. drinking water dams). Overall, main source in Europe s countries is groundwater with some 50% (Figure 2-1). The distribution of water sources in European countries is shown in Figure 2-2. Figure 2-1 Sources for drinking water in Europe (2011 to 2013) 1% 3% 8% 2% 6,3% Groundwater Surface water Inland water 49% Coastal water Bankfiltration water 31% Other water Artificial Groundwater Recharge Figure 2-2 Sources for drinking water in European countries (2011 to 2013) AT DK LT SK IE DE SI LV PL BE IT NL EE FR HU MT FI BG RO ES CZ* PT GR LU SE GB CY [%] Artificial Groundwater Recharge Other water Bankfiltration water Coastal water Inland water Surface water Groundwater *In CZ, inland water is synonymous with surface water 6 European drinking water quality

7 Figure 2-3 shows the percentage of resident population to large water supply zones (>1,000m³/day and/or supplying more than 5,000 people). For some countries, also resident population for small water supply zones were reported within the period 2011 to Under consideration of small water supply zone residents, Malta, Hungary, Slowakia, Portugal, France, and Bulgaria reach 100% resident population, too. Slowenia reach 90% and Romania 66% resident population. Figure 2-3 Population with access to drinking water (large water supply zones) in European countries (2011 to 2013) Resident population [%] BE CY ES IE LU NL MT GR UK HU SK DE PT SE FI FR BG CZ SI PL AT IT EE DK LV LT RO 2.2 Drinking water quality To assess drinking water quality in a water supply zone, a huge number of analyses within reporting period in European Member States have been carried out: microbiological parameters (3.5 million analyses), chemical parameters (5.7 million analyses), indicator parameters (13.8 million analyses). For each parameter, information on compliance was available. Percentage of compliance reflects the ratio of number of analyses done and number of analyses with exceedances. Compliance with the Directive means more than 99 % of all analyses done fall below the given standard. Exceedances of indicator parameters do not necessarily mean a non-compliance of the Directive because of the above mentioned reasons (if there is no direct threat to human health). Figure 2-4 shows the percentage of compliance for the parameter groups: (a) microbiological parameters, (b) chemical parameters, and (c) indicator parameters in Europe. The results show a high number of compliance due to microbiological and chemical parameters. Indicator parameters reach almost 99 % of compliance in the Overall, compliance rates of parameters are high in Member States and indicate a really high level of drinking water quality in Europe. reporting years 2012 and European drinking water quality

8 Figure 2-4 Percentage of compliance for the parameter groups microbiology, chemicals and indicator parameters for the reporting period in Europe 100, Percent compliance with the Directive 99,5 99,0 98,5 98,0 97, ,0 Microbiological parameters Chemical parameters Indicator parameters Chyba! Chybný odkaz na záložku. shows the information on compliance for the chemical parameters in Europe. According to chemical parameters, individual pesticides show in contrast to nearly all other parameters the lowest compliance rate with 93.7 %. Pesticides comprise a group of organic substances and their relevant metabolites, degradation and reaction products. According to risk assessment, only those pesticides which are likely to be present in a given supply need to be monitored. Due to individual pesticides, the parametric value of 0.1µg/l applies to each individual pesticide, whereas pesticides total means the sum of all individual pesticides detected and quantified in the monitoring procedure. Figure 2-6 shows the information on exceedances for indicator parameters. The figure just gives an overview of the exceedances and does not reflects non-compliance of the directive, because a number of indicator parameters do not have a numeric value, such as colour, taste, odor, or turbidity and not all Member States reported on the level of (non)-compliance with the indicator parameters as they considered it a mere indication that needs investigation rather than a real non-compliance with the Directive. Nevertheless, parameters that most frequently showed exceedances due to indicator parameter group are chloride, sodium, coliforms and iron. 8 European drinking water quality

9 Figure 2-5 Percentage of compliance for the chemical parameters (mean value of reporting period ) in Europe 1,2-dichloroethane Benzene Cadmium Cyanide Chromium Mercury PAH Pesticides-Total Tetra-/Trichlorethene Selenium 2,6-dichlorbenzamide Benzo(a)pyrene Bromate Antimony Copper Lead Nitrate Nitrite Boron Nickel Trihalomethanes-Total Arsenic Pesticides-Individual compliance % Figure 2-6 Percentage of analyses with no exceedances for the indicator parameters (mean value of reporting period ) in Europe except colour, taste, odour, and turbidity parameters not exceeded % Conductivity ph Clostridium Aluminium Total Organic Carbon Fluoride Oxidisability Ammonium ColonyCount Manganese Iron Coliform Sodium Chloride European drinking water quality

10 Excursus: Pesticides in drinking water Pesticides can certainly be classified under contaminants of concern in the case of aquifer recharge. These chemicals may not expect to be important at domestic level, but are apparently found on a regular base in domestic wastewater. Pesticides are used in private gardens and at municipal level, and mainly originate from agricultural runoff. Much effort has been put into the standardization of pesticides in drinkingwater. Standards are based on an indicator approach and do not really reflect acceptable concentrations A. Künzelmann, UFZ from a health point of view. According to the drinking water directive, a concentration limit of 0.1μg/l is set for individual pesticides, and the sum of the pesticides must not exceed 0.5μg/l. Because pesticides are present on a regular base and in low concentrations, exposure to these chemicals is generally chronic. The health risk from such exposure is difficult to assessed, because data on acceptable doses for chronic exposure are scarce and the low concentrations involved are difficult to monitor. Member States monitor a huge number of national specific pesticides and metabolites in drinking water. However, only for a short list of 13 pesticides, which was agreed between European Commission and Member States, reporting of monitoring frequency and information on noncompliance is mandatory. Even though the reporting of pesticides short list is a harmonised approach and comparable, it shows not the full picture of all pesticides and all relevant metabolites in a country. Whereas pesticides total shows a compliance rate of more than 99%, individual pesticides, which includes the regional specific substances and all relevant metabolites, shows the highest noncompliance rate of all chemical parameters with more than 6% (see Chyba! Chybný odkaz na záložku. shows the information on compliance for the chemical parameters in Europe. According to chemical parameters, individual pesticides show in contrast to nearly all other parameters the lowest compliance rate with 93.7 %. Pesticides comprise a group of organic substances and their relevant metabolites, degradation and reaction products. According to risk assessment, only those pesticides which are likely to be present in a given supply need to be monitored. Due to individual pesticides, the parametric value of 0.1µg/l applies to each individual pesticide, whereas pesticides total means the sum of all individual pesticides detected and quantified in the monitoring procedure. Figure 2-6 shows the information on exceedances for indicator parameters. The figure just gives an overview of the exceedances and does not reflects non-compliance of the directive, because a number of indicator parameters do not have a numeric value, such as colour, taste, odor, or turbidity and not all Member States reported on the level of (non)-compliance with the indicator parameters as they considered it a mere indication that needs investigation rather than a real non-compliance with the Directive. Nevertheless, parameters that most frequently showed exceedances due to indicator parameter group are chloride, sodium, coliforms and iron. 10 European drinking water quality

11 Figure 2-5). This indicates a huge problem with pesticides in drinking water caused by human activities in the catchment, agriculture especially. Here, especially the protection of raw water is particularly important. Critical groundwater bodies need special focus for specific measures for drinking water. But that cannot be solely the task of the water suppliers. Rather, close cooperation of various stakeholders is needed, mainly to plan and implement measures also in the catchment area. To protect drinking water against pollution from the catchment area, there must be a well-integrated link between the Drinking Water Directive and the other water related directives, like the Water Framework Directive, the Bathing Water Directive, or the Nitrates Directive. 2.3 Causes of non-compliance Due to the reporting obligations, causes and remedial actions need to be reported for non-compliance analyses in a WSZ. This means, the number of causes depends on the number of non-compliant analyses. Failures suspected to be caused by contamination of the source water are defined as catchment related causes, like discharges from wastewater treatment plants or stormwater overflow, agricultural activities (use of fertilizer and pesticides), or industrial activities. Treatment related causes are mainly associated with the treatment processes at the plant, like chemical dosing regimes, coagulation and clarification procedures, filter operation, or disinfection. Within the distribution network causes for contamination could be flow reversals and pressure changes, changes in the flushing or scouring regime, or leakages. Failures associated with the domestic distribution network could only be identified at the consumers tap. Non-compliances with the standards for copper, lead and nickel at the consumer s tap may be associated with the consumer s pipe work and fittings. Figure 2-7 shows the main parameters of which causes for exceedances were reported. The assessment is based on a water supply zone scale. This means that exceedance of a parameter were counted once in a water body although several analyses have exceeded the parametric value. This is because exceedances of a parameter are often due to one temporal specific incident. In the reporting period , in some 30,000 WSZ, causes for exceedances were reported (2011: 10,160; 2012: 10,100; 2013: 10,070). Based on this, coliform bacteria seem to be by far the most common problem in Europe s drinking water. Furthermore, it should be noted, that coliform bacteria is also the most analysed parameter in Europes drinking water with some 2.5 million analyses in the reporting period A number of causes were also reported for Iron, microbiological parameters beneath coliform bacteria, total organic carbon, turbidity, manganese and aluminium. Figure 2-7 Number of WSZ with reported causes in case of exceedances for the parameters of the drinking water directive in Europe ( ). European drinking water quality

12 Number of water supply zones Coliform Iron Colony Count E.coli Total Organic Carbon Turbidity Enterococci Clostridium Manganese Aluminium ph Lead Nickel Nitrite Sulphate Odour Colour Taste Ammonium Trihalomethanes-T Arsenic Chloride Pesticides-I Sodium Fluoride Nitrate Bromate Figure 2-8 shows the different causes for the most reported parameters. While the causes for exceedances due to some parameters cannot be exactly specified (e.g. coliforms, turbidity), exceedances of TOC or Aluminium are mainly treatment related. Microbiological parameters except coliform bacteria are mainly both, public distribution network and treatment related, rather catchment related. Lead and Nickel are clear associated with problems in domestic distribution network and exceedances in ph originate mainly in the catchment. Figure 2-8 Causes of non-compliance for the most reported parameters 12 European drinking water quality

13 0% 20% 40% 60% 80% 100% Coliform Iron ColonyCount E.coli TOC Turbidity Enterococci Clostridium Manganese Aluminium ph Lead Nickel Catchment Domestic distribution network Other causes Public distribution network Combined causes Treatment related Unknown 2.4 Country comparison Non-compliance of parameter groups is presented in Table 2-1 at national level in the EU Member States. The assessment based on a mean compliance rate for each parameter group of the years 2011 to Table 2-1 Compliance rates at national level in the Member States ( ) Country Microbiological parameters Chemical parameters Indicator parameters* AT BE BG CY CZ DE DK EE ES FI FR GR HU IE IT LT European drinking water quality

14 Country Microbiological parameters Chemical parameters Indicator parameters* LU LV MT NL PL PT RO SE SI SK UK % rate of compliance % rate of compliance *except odor, taste, colour and turbidity As regards the microbiological parameters, all Member States except Spain reported between compliance, Concerning the chemical parameters, 25 Member States reported compliance of between %, and two Member States reported compliance between %. For the indicator parameters there were five Member States that had a compliance rate between 99 and 100%, out of which 21 Member States had a compliance level of %. For indicator parameters, Malta reported a mean compliance rate of less than 98 % because of very low compliance rates due to sodium. 14 European drinking water quality

15 3 Measures to improve drinking water quality Where further improvement in the quality of drinking water is needed, the action that should be taken depends on the parameter and the cause (see Figure 2-8). A distinction has to be made between parameters that relate to human activity in the catchment such as nitrate or pesticides. In these cases, measures need to be taken to improve site specific source protection over a longer time period (e.g. improvements in waste water treatment plants, restriction of use within the zone of contribution) also in liaison with the teams implementing the River Basin Management Plan under the Water Framework Directive. In the short-term remedial actions could be introduction of additional treatment or a change of source of raw water, which might however require longer water transfers. Remedial actions due to treatment are e.g. changes in chemical dosing regime, coagulation, clarification procedures, filter operation (backwashing arrangements) or disinfection. Distribution network related remedial actions are inter allia flushing/scouring the mains, or replacement/ refurbishment of corroded/leaking pipe work. In the case of loss of drinking water quality that is linked to the use of materials such as lead, copper and nickel problems are often related to the domestic distribution network and in-house installation and can only be solved through conditioning of the water and information to the public of the proper use of materials and actions they can take to avoid too high levels in their drinking water. Figure 3-1 shows the percentage of remedial actions for three parameters, which causes noncompliance or had a higher number of exceedances: coliform bacteria, lead and total organic carbon (TOC). Figure 3-1 Percentage of remedial actions for selected water quality parameters in Europe ( ) Coliform bacteria Lead Total Organic Carbon (C=catchment; D=domestic distribution network; E=emergency; P=public distribution network; T=treatment) C1 Action(s) to terminate or mitigate the cause N None Required C2 Action(s) to replace source O Others D1 D2 E1 Replacement, disconnection or repair of defective components Cleaning, scouring and/or disinfecting contaminated components Notification of and instructions to consumers e.g., prohibition of use, boil water order, temporary limitations on consumption. P1 P2 T Replacement, disconnection or repair of defective components Cleaning, scouring and/or disinfecting contaminated components Establishing, upgrading or improving treatment European drinking water quality

16 The distribution of remedial actions in case of coliform bacteria contamination is diverse and reflects also the reported causes (see Figure 2-8). Main remedial actions are related to public distribution network, treatment, minor distribution network and unspecified ( Others ). In the case concentration of lead exceeds the parametric value, 43% of all reported remedial actions were replacement or disconnection of lead pipes in the domestic distribution network and also a number of emergency actions (14%). 63% of all reported remedial actions in case of TOC exceedances were treatment related. To summarize, it can be noted that specific drinking water quality parameters or groups of parameters are causing problems at different points of extraction: water source, treatment, distribution and end of pipe - the consumer. That makes it difficult to develop a transparent and useful monitoring, to identify the causes of non-compliance, and to implement measures to maintain a healthy supply of drinking water in Europe. A. Künzelmann, UFZ 16 European drinking water quality