Freshwater quality — SOER 2010 thematic assessment
- Freshwaster quality.pdf [14.9 MB]
Main pollutant sources: agriculture and the urban environment
Despite improvements in some regions, pollution from agriculture remains a major pressure on Europe's freshwater. Nutrients (nitrogen and phosphorus) from fertilisers, pesticides, organic material, sediment and pathogenic micro-organisms are washed to waterways, primarily via diffuse pathways. Cost-effective measures exist to tackle agricultural pollution and need to be implemented through the WFD, while full compliance with the Nitrates Directive is also required. The forthcoming reform of the Common Agricultural Policy provides an opportunity to further strengthen water protection.
The urban environment generates a range of pollutants including industrial and household chemicals, metals, pharmaceutical products, nutrients, pesticides and pathogenic micro-organisms. The UWWTD has led to more of the EU's population being connected to a municipal treatment works via a sewer network and to a reduction in the wastewater discharge of some pollutants to receiving waters. However, there is considerable scope for increased control of pollutants at source which reduces the burden on the treatment process including the consumption of energy. Full-cost pricing for wastewater services will help drive controls at source. Storm overflows in the urban environment also remain a significant concern.
Excessive concentrations of phosphorus are the most common cause of freshwater 'eutrophication' — characterised by a proliferation in the growth of problematic algal blooms and an undesirable disturbance to aquatic life. Phosphorus levels in freshwater have declined in recent years due primarily to improved wastewater treatment and bans on phosphates in detergents. However, this trend has slowed suggesting that a greater targeting of diffuse sources of phosphorus is required for further improvements to occur.
While some declining trends in nitrate concentrations are apparent, current levels of nitrate in a number of Europe's rivers are often of a magnitude sufficient to promote eutrophication in receiving coastal waters. Many countries also report groundwater bodies with nitrate concentrations above threshold levels. Clear downward trends in organic pollution are evident in most of Europe's rivers, mainly due to measures implemented under the UWWTD, although these trends have levelled in recent years. The quality of EU inland bathing waters has improved significantly since 1990 — in 2009, 89 % of inland bathing areas complied with mandatory values. Information describing pesticide levels in freshwater remains incomplete across Europe.
Pollutants in some of Europe's freshwaters have led to detrimental effects on aquatic ecosystems and the loss of freshwater flora and fauna. Aside from eutrophication, which remains widespread, chemicals with endocrine‑disrupting properties have been shown to trigger feminising effects in male fish, raising implications for their fertility. Pesticides and metals can be toxic to aquatic life, while concern is growing about the effects of chemical mixtures found in Europe's more polluted waters. Much of the pollutant load in freshwaters is ultimately discharged to coastal waters with the potential to adversely impact the quality of the marine environment. Poor water quality is also a potential threat to public health through various exposure routes.
Outlook and response
The implementation of a comprehensive range of water‑related legislation, led by the WFD, will continue across Europe in the coming years. Currently, reporting under the WFD indicates that a substantial proportion of Europe's freshwaters are at risk of not achieving good status. Strong, cost-effective and timely measures therefore need to be implemented, addressing all pollutant sources. They must also ensure that resources, including water, energy and chemicals, are used in an efficient manner. The extent and effectiveness of measures to be implemented also need to account for driving forces that could affect water quality over the coming decades, including climate change, increasing global food demand and an expansion of the cultivation of bioenergy crops.
For references, please go to http://www.eea.europa.eu/soer/europe/freshwater-quality or scan the QR code.
PDF generated on 23 Feb 2017, 06:09 PM