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Low quality of drinking water

Latvia is endowed with adequate water resources to fully provide its population with drinking water. Therefore our main objectives are to ensure that drinking water is of adequate quality and that water resources are sustainably used.

An average of 95% of the population in Latvian cities, and an average of 50% in towns, receive their drinking water from a centralised supply system. Both surface water (53%) and groundwater (47%) are used for water supply.

In a centralised water supply system, the main threats to drinking water quality are presented by:

1. Use of surface water polluted as a result of human activity. Surface water is used to supply part of the drinking water for Riga, Daugavpils, Ventspils, Olaine and several other towns.

Large facilities for the treatment of drinking water have been constructed in these cities, where surface water undergoes pre-chlorination, coagulation, filtration, sedimentation and secondary chlorination. However, even this cannot fully safeguard the populations against chemical pollution of their water supply, especially if that pollution is of an accidental or transboundary nature.

Apart from this, water treatment facilities also pollute water to a certain extent, when they discharge large volumes of used coagulants. The effects of chlorination on drinking water quality and the consumer is also an unresolved issue.

2. The poor technical condition of water supply systems and equipment, together with their sometimes negligent and irresponsible operation, adds the threat of bacterial pollution to those already mentioned.

Latvian groundwater characteristically has a high iron content and insufficient fluorine. If evaluated according to these indicators, about one third of all existing wells fail to meet the existing standards.

Overall, groundwater is unpolluted, of satisfactory bacterialogical quality, and disinfection is not necessary. Whether or not water should be treated prior to its supply to consumers should be evaluated separately for each locality.

As a result of the intensive use of groundwater, depression funnels have formed in several regions. In the vicinity of Riga, the water-bearing layer is 7 m lower than the norm. Around Liepâja, it has dropped by 15 to18 m thus allowing the intrusion of sea water. There are also local depressions in water abstraction zones near Ogre, Tukums, Jelgava and Sigulda.

The main sources of drinking water for individual consumers that are not connected to communal water supply networks (i.e. on farms, rural properties, some dwellings in villages and towns, also areas of summer houses and garden houses) are dug wells or shallow drillholes. The majority of wells are 2...6 m deep.

The water from such wells or shallow drillholes generally has a high organic content, that is connected with waterlogging or the leaching of humic substances. The high concentration of nitrogen compounds in such wells should also be particularly noted. This is generally due to incorrect well construction techniques and the untidiness of adjacent areas. Biological pollution is considered a serious problem - high concentrations of unicellular organisms, algae and micro-organisms have been found in well-water. In all, 15...20% of wells can be considered polluted, and use of this water may have adverse impacts on human health. *

The following measures may be used to improve drinking water quality:

transition to the use of groundwater for centralised water supplies, while at the same time ensuring its sustainable and efficient use. Necessary instruments:

• State and local government financial investments;
• foreign loans, with State guarantees in some cases;
• optimisation of tariffs for water use.

improvement, completion and expansion of water supply systems. Necessary instruments:

• optimisation of water tariffs;
• improvement of permit system for water abstraction;
• foreign loans;
• financial investments by local governments;
• local development planning;
• application of the natural resources tax to water users not connected to centralised water supply systems;
• elaboration of national drinking water standards in accordance with EU requirements.

protection of drinking water abstraction sites.

Necessary instruments:

• implementation of the law ‘On Protection Belts’ and ensuring the enforcement of its protective provisions;
• information and education of the public;
• administrative penalties.

improvement of individual and local water supply systems and the protection of upper layers of groundwater against pollution. Necessary instruments:

• programmes for the development of local water supply systems;
• information and education of water consumers;
• territorial planning;
• local government subsidies and soft loans;
• decontamination of local groundwater pollution sources, pollution minimisation.

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* Study of water of wells in Latvia, University of Latvia, 1994, Riga.

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Last updated: November 8, 1996. The information prepared by Valts Vilnitis: fuxis@varam.gov.lv