B - High ecological complexity
While the quality of river water across Europe has improved significantly thanks to a range of EU environmental legislation since the 1970s, pressure from agriculture, urbanisation, tourism and climate change suggest that guaranteeing water quality must continue to be a priority. Water quality is a complicated issue underlined by the influence of various pressures and multi-cause/multi-effect relationships and the many forms that pollution can take. Pollution is defined by the WFD as “the direct or indirect introduction, as a result of human activity, of substances or heat into the air, water or land which may be harmful to human health or the quality of aquatic ecosystems or terrestrial ecosystems directly depending on aquatic ecosystems, which result in damage to material property, or which impair or interfere with amenities and other legitimate uses of the environment”. According to the last report on the implementation of WFD , 15% of surface bodies and 14% of the groundwater are affected by point source pollution “as a significant pressure” (urban wastewater, industrial wastewater, contaminated sites, waste disposal, mining, and industrial sites). 22% of surface water bodies and 28% of the groundwater are affected by diffuse pollution from agriculture “as a significant pressure”. The EEA underlines that mercury from atmospheric deposition is “the main reason for failing good chemical status in more than 30% of surface water bodies”
. Although progress has been made in reducing pollution of freshwater from point sources, the diffuse pollution remains a major concern. In addition, new alerts have been confirmed concerning certain types of pollutants such as pharmaceutical residue, endocrine disruptors, microplastics or emerging pollution by nanoparticles
.
The EEA thus further notes that many organic pollutants, including sewage effluent as well as farm and food-processing wastes, consume oxygen, suffocating fish and other aquatic life. The largest sources of organic waste load are: household waste-water; industries such as paper industries or food processing industries; and occasionally silage effluents and slurry from agriculture. Increased industrial and agricultural production, coupled with a greater percentage of the population being connected to sewerage systems, initially resulted in increases in the discharge of organic waste into surface water. Over the past 15 to 30 years, however, the biological treatment of wastewater has increased, and organic discharges have consequently decreased throughout Europe. Nutrients, such as nitrates and phosphates contained in farm fertilisers and household detergents can over-fertilise the water, causing the growth of large mats of algae, some of which can be toxic. In severe cases of eutrophication, planktonic algae spreads. As dead algae decompose, the oxygen in the water is used up, bottom-dwelling animals die and fish either die or leave the affected area. Increased nutrient concentrations can also lead to changes in the aquatic vegetation. Nutrients are discharged into the aquatic environment by the operation of many human activities, e.g. through wastewater from households and industry or by loss of nutrients from agriculture and fish farming. Agriculture is the main source of nitrogen loading and a major source of phosphorus loading, although much phosphorus also comes from point sources and sparsely built-up areas. Pesticides and veterinary medicines from farmland and chemical contaminants, including heavy metals and some industrial chemicals, can threaten wildlife and human health. Wastewater contains many hazardous substances derived from detergents and other substances, and many substances are used in industrial production and in the transport sector. Pesticides and other substances leach from contaminated sites. Pesticides also occur in watercourses. The quality of the groundwater is threatened by various factors, such as leaching of nitrate and pesticides from cultivated land, as well as more restricted contamination from point sources, such as waste chemicals deposits, landfills, oil tanks and contaminated sites.
Among the human activities causing pressures on freshwater, agriculture is identified by Member States “as one of the main drivers for failure to achieve good status in EU Water bodies” both through diffuse pollution and water abstraction. In 2017, agriculture was the first water user (58%) in Europe after the sector of energy production (18%), mining, construction and manufacturing industries (11%), households (10%) . This percentage hides great disparities among Member States and the quantitative pressure is much higher, especially in southern European countries (up to 80% water use for agriculture). According to Member States, in their second River Basin Management Plan, around 8 000 surfaces water bodies (6%) are affected “by significant pressures from abstraction with the highest shares in Hungary, Spain, Cyprus and Bulgaria. Some studies show that 50% of the EU rivers’ basins will face water scarcity and stress in the current state of climate change
.
For recreational activities such as swimming, faecal contamination from sewage and animals is a cause of concern for public health. Such pollution increases during heavy rain and floods, when pollution is washed into rivers and seas, and by overflowing sewerage networks. Forty years ago, large quantities of uncontrolled, untreated or partially treated wastewater were discharged into many of Europe's waters. The last report of the EEA shows that bathing quality remains high and “88% of EU coastal bathing sites are classified as being of excellent quality compared to 78,8% of inland sites” . The share of poor-quality bathing water sites dropped to 1.5 % in 2021 compared to 2% in 2013. If the number of bathing waters has decreased from 2020 by 417 amounting to 21 859 bathing sites in 2021
, the EEA indicates that 223 new sites have been identified in 2021 in the Member States.