Water quality studies: Monitoring our freshwater sources

Recent decades have seen the impact of human activity on global freshwater resources rise, underlying the need for water quality studies and monitoring as a basis for effective water management strategies.

Acidification of lakes due to industrial pollution and poisonous discharges into waterways resulting from industrial manufacturing are just two of the effects of increased industrialisation and fossil fuel consumption.

Agriculture adds further pressure by contaminating freshwater resources with pesticides and nitrates. Moreover, soil erosion transports sediment into streams, reducing water quality and depositing silt.

The complex threats that human actions pose to water ecosystems make it imperative to conduct comprehensive assessments of water quality trends. Addressing current and future water pollution risks requires accurate data, which can only be acquired through consistent monitoring.

The International Organisation for Standardisation (ISO) defines water quality monitoring as “the programmed process of sampling, measurement and subsequent recording or signalling, or both, of various water characteristics, often with the aim of assessing conformity to specified objectives”. Ultimately, the data collected helps water quality management decision-makers to address matters like pollution, land use and the amount of water abstraction.

The World Health Organisation (WHO) identifies three types of monitoring activities, covering different time spans:

· Monitoring involves long-term measurement and observation of the aquatic environment to establish status and trends.

· Surveys are intensive programmes measuring and observing the quality of the aquatic environment for a specific purpose.

· Surveillance is continuous, specific measurement and observation for water quality management and operational activities.

Water quality assessments serve a variety of purposes, but generally produce information on levels and trends in water quality indicators, both physical and chemical. Accurate data help to identify emerging water quality problems and provide a basis for improving future strategies.

Water quantity is usually measured more frequently than water quality, as monitoring numerous parameters affecting water quality is more expensive than tracking just a few water quantity variables, according to the United Nations Environment Programme (UNEP).

Water quality studies require a team to collect samples from stations, while water level, discharge and velocity can often be analysed in remote hydrological monitoring stations. Satellite observations are also increasingly used to monitor global water resources.

UNEP maintains a global water quality database, making available information on over 100 parameters collected from thousands of stations worldwide.

Europe’s contribution

The EU’s Water Framework Directive , adopted in 2000, requires member states to establish monitoring programmes to assess the status of surface and groundwater in river basins. Such monitoring is crucial to assessing progress towards the directive’s aim of achieving ‘good’ status for Europe’s waters by 2015.

The programmes cover the volume of water resources, their chemical status and their ecological potential.

There is a “good monitoring effort” across the EU, according to the European Commission’s April 2009 progress report. The results were nevertheless patchy. Station density varied widely, but this could be partly attributed to factors like population density and water use. The UK came top, with 52 stations per 1,000 km², while Finland had less than 1.

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