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Kvaliteten af det danske drikkevand for perioden 2002-2004 Summary and conclusions
BackgroundThis report is the first of its kind that Denmark has prepared, with the objective of informing consumers of the quality of the drinking water in Denmark for the years 2002-2004. Denmark is to publish such a report every three years, according to Council Directive 8/83/EC of 3 November 1998 on the quality of water intended for human consumption, also known as the drinking water directive. The directive is implemented in Denmark through the water supply act (Act. No.130 of 26 February 1999 on Water Supply etc.) and the inspection statutory order (Statutory order no. 871 of 21. September 21, 2001 on Water quality and inspection with water supply systems). Legislation and Parametric valuesIn connection to the inspection statutory order the Danish EPA has published 2 guidance's in order to accommodate the water supplies and the inspection authorities. The parametric values have been set in the inspection statutory order, annex 1a-1d. The parametric values concerning drinking water have been set at 3 places along the distribution system. When leaving the water work, at the property entrance and at the tap of the consumer. Regarding parameters that are not influenced by the distribution system, the value is the same at all 3 points of control. Regarding parameters that are changed due to reaction with oxygen in the pipe systems or due to direct leaching of substances to the water from the pipes themselves, different values have been set in order to ensure compliance of the values at the consumers tap. The municipal council is the inspection authority with regard to drinking water, and it sets down the monitoring programs in agreement with the waterworks with regard to the minimums standards set in the inspection statutory order. In cases of lack of compliance the municipal council prescribes investigation in order to identify the cause to the failure of compliance followed by remediation. Furthermore the National Board of Health is involved. The municipal council ensures, that the consumers of the water supply system immediately are informed of the exceeded parametric value(s) as well as the measures each consumer should adopt in the given situation. The Danish water supply systemIn Denmark nearly all drinking water is produced from groundwater. Thus the Danish water supply is based on approx. 99% groundwater and 1% surface water. The number of small water abstractions, e.g. the wells that extract less than 350.000 m³ pr. year, has been around 3247-3336 in 2002-2004 and thus constitutes the greater part of the water abstractions. Totally the small water abstractions abstract approx. 150 mill m³ pr. year. At the same time the big water abstractions, those are the wells that abstract more than 350.000 m³ pr. year, are responsible for abstracting approx. 270 mill m³ pr. year. In total during 2002-2004 there has been abstracted approx. 418 mill m³ pr. year from all wells. In Denmark we have approximately 2700 water supplies which is about 1000 less than the number of water abstractions. There can be several water abstractions connected to a single water supply, and therefore the number of water abstractions is not identical to the number of water supplies. Besides those water supplies there are an estimated number of 70.000-80.000 single water abstractions, e.g. water supplies that supply less than 10 properties. As a rule those supplies consist of a well or a boring and are designated as single abstractions. The Drinking water qualityThe quality of the drinking water has been made up in 2 tables. Their points of reference are the parameters appearing in the inspection statutory order, annex 1a-1d and the parametric values set at the point where the drinking water leaves the water work and at the property entrance. The making up of the drinking water quality is based on data from water supplies that abstract more than 350.000 m³ pr. year for the years 2002-2004, since the report according to the drinking water directive as a minimum shall include all individual supplies of water exceeding 1000 m³ a day as an average. The control shows that for most of the parameters, both chemical and microbiological, there is almost 100% compliance. For a few parameters the compliance is a bit lower (74-85%). It is not possible to obtain information on whether an investigation has taken place in order to determine the cause to the failure of compliance, based on the database that holds information about analyses etc. The control of organic substances, is not included in the limited control, which takes place in the water supplies pipe lines. Usually those compounds are monitored in the waterworks or in the abstraction wells. An explanation can therefore not be given as to why those substances have been analysed on the pipe line. DerogationsIf the water from a water supply does not comply with the parametric values, the municipal council has the power through a measure, given in accordance with the water supply act, to derogate from the parametric values. Although derogation can not be given to the microbiological parametric values except from colony count 22°C. In connection with the derogation the municipal council must inform the affected consumers in a suitable way, about the conditions concerning the derogation and if necessary, provide guidance to the consumers regarding the extend, of the risk the derogation might assume. It is possible to grant derogation for 3 periods, each period not exceeding 3 years. The first derogation is given by the municipal council. Derogations to water supplies that have permission to abstract more than 350.000 m³ pr. year are reported to the Danish EPA. Second period derogations are given by the county council, which reports all derogations to the Danish EPA. Exciding the county councils third period derogation, the Danish EPA and the European Commission must have granted the derogation. The new parametric values in the inspection statutory had to bee complied with at the latest on 25. December 2003, unless derogation has been granted. Up to that time there had to be compliance with the parametric values set in the former inspection statutory order from 1988. Therefore the first derogations were given after 25. December 2003. 7 first time derogations have been granted since December 2003. Out of those, 3 water supplies have been granted a second period derogation. The general picture shows, that the first period derogations have been given to parameters that can be referred to substances naturally occurring in groundwater. According to the previous statutory it had been possible for most of those parameters to set higher parametric values, since it was of no immediate health importance.
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