UK Progress on Reducing Nitrate Pollution Contents

1Introduction, Nitrogen Pollution, Air and Water Quality and its Regulation


1.We decided to look at the issue of nitrate pollution for several reasons. One was the continuing problem of water quality. For instance, in October 2015, it was reported that the majority of water bodies in England were failing to achieve good status and that the Environment Agency was struggling to bring them into compliance with European legislation, despite the UK having a derogation that moved the target for compliance from 2015 to 2027.1 While there has been some improvements in the quality of bathing water,2 the poor ecological status of water systems continues to be problematic for our wildlife and pollution of groundwater sources affects a major source of our drinking water.3 Nitrates are one of the key nutrients involved in the pollution of rivers and streams and are the main pollutant in groundwater sources. They are predicted to worsen for some time to come.4 We also considered the related issue of air quality, particularly ammonia and nitrogen oxide emissions.5 These are related to nitrates, because ammonia and nitrogen oxides are part of the wider nitrogen cycle and emissions largely emanate from the same agricultural sources as nitrates.6 Ammonia and nitrogen oxides can also damage ecosystems, especially water ecosystems.7

2.We were therefore keen to investigate how the Government was addressing the related issues of nitrate pollution and water and air quality. We looked at the implementation of current regulations, the role of the Environment Agency, the Rural Payments Agency and Natural England in monitoring progress and enforcing compliance, and how stakeholders, such as water companies and farmers, fitted in. We also wanted to assess some of the Government’s initiatives, such as its new Farming Rules for Water (introduced in April 2018) and its Clean Air Quality strategy (published in July 2018), and other measures it might consider.

3.EU Directives and their transposition into UK law are central to the regulation of water and air quality standards and addressing specific pollutants such as nitrates, ammonia and nitrogen oxides. They are also key to the UK meeting several of the United Nations’ Sustainable Development Goals, particularly on Clean Water and Sanitation, Climate Action, Life Below Sea and Life on Land.8 EU funding to UK farms through the Common Agricultural Policy (CAP) is contingent on a mechanism of cross-compliance that links direct payments to compliance by farmers with basic standards including those for the environment and water quality.9 EU institutions, such as the European Environment Agency provide administrative support and advice, while the European Commission and European Court of Justice monitor and enforce compliance and penalise Member states when they do not comply.10 This Report follows our previous Inquiries, such as those into fluorinated gases and the regulation of chemicals, and explores what impact leaving the EU would have on policy areas that are dependent on EU regulation, oversight, compliance and enforcement mechanisms, and examines the Government’s proposals for the system that will replace these mechanisms. We also considered the particular challenges that a post-EU system will pose for Northern Ireland and the Republic of Ireland, who share several water bodies and who may, in future, have divergent policies on water and air quality.

The Nitrogen Cycle

4.Nitrates are produced as part of a wider nitrogen cycle. Understanding this cycle and its interaction with human activities, such as farming, sewage and transport and industrial emissions, is important if one is to tackle nitrogen as both a water and atmospheric pollutant.11 The nitrogen cycle is the biochemical cycle by which nitrogen is converted into its multiple forms as it circulates among the atmospheric, terrestrial and marine ecosystems. There are two main forms of nitrogen - organic and inorganic. Organic nitrogen is found in proteins and is continually recycled by plants and animals,12 including tens to hundreds of thousands of compounds that make up dissolved organic nitrogen and dissolved particulate nitrogen.13 Inorganic nitrogen occurs as nitrogen (N₂) nitrate (N0₃-), nitrite (NO₂-), ammonia (NH₃+) and ammonium (NH₄+).14

Nitrogen as a Pollutant

5.Within certain levels, nitrogen is beneficial to animals, plants and the wider environment. It is needed for processes such as the production of amino acids, proteins and human DNA and required to make chlorophyll in plants which drives photosynthesis.15 However, if nitrogen - in the form of ammonia, one of the gaseous nitrogen oxides,16 or nitrates or nitrites - is highly concentrated, it can have a damaging impact on ecosystems and the organisms that depend on them.17 In water bodies this can lead to eutrophication, whereby an excessive richness of nutrients including nitrates can cause a dense growth of plant life and algae. This depletes the oxygen in the water body, which can result in reduced biodiversity.18 Nitrates can also reduce oxygen in drinking water, which can be harmful to people; for example, causing methaemoglobinaemia (‘blue baby syndrome’).19 In the form of ammonia and nitrous oxides, nitrogen can become a toxic air pollutant, greenhouse gas and can lead to the acidification of water sources. For more detail on the impact of nitrogen pollution see Annex 3.

Sources of Nitrogen Pollution

6.Agriculture is a key source of nitrate pollution,20 ammonia emissions,21 and nitrous oxides emissions.22 Manufactured fertiliser containing urea, ammonium and nitrate applied to the land can leach from soils into nearby water sources, especially if soil health is poor and nitrates are not retained.23 Animal waste, either slurry, manure or applied as an organic fertiliser, can also leach into water sources or break down into ammonia and nitrous oxides that can be released into the atmosphere. Nitrates and other pollutants such as phosphates can also be released from domestic and industrial sewage into water sources, which may cause eutrophication. Nitrogen oxides, ammonia and particulate matter can also be released from road transport, industrial processes and the energy sector. For a detailed overview of the sources of nitrogen pollution see Annex 1.


7.Though phosphorous is not part of the nitrogen cycle it has similarities with nitrates as a pollutant. It is an essential building block of life and an irreplaceable part of modern agriculture.24 It is a constituent of plant cells, essential for cell division and development of the growing tip of the plant; without it, plant growth is retarded.25 However, losses from agricultural fields can cause eutrophication and ecological deterioration of surface waters.26 The main sources of phosphorous in surface waters are sewage and effluent, and run-off from agricultural land, with the latter usually highest in winter when water levels are higher.27 Generally speaking, phosphorous is more of a pollutant in rivers and less of an issue in groundwater sources, though this depends on local geology. We were told that water quality was affected by a combination of different pollutants, including nitrogen and phosphorous, and that the cycle of both nutrients and their interaction with each other needed to be understood to improve the ecological status of water sources.28

The Regulatory Regime for Water Quality, Nitrates and Air Quality.

Water Quality and Nitrates

8.Water quality across the EU is regulated by several Directives. The key Directive is the Water Framework Directive, established for the assessment, management, protection and improvement of water quality.29 It stipulates that EU member states should aim to achieve good status of water in all bodies of surface and ground water by 2015, or 2027 by the latest. It is supported by Directives on drinking water, bathing water, urban waste water and nitrates. An overview of the various directives is provided in Annex 2 of this Report.

9.The Directives are transposed into UK law mostly by secondary legislation and complemented by guidance. The Environment Agency is the principal regulator in England for breaches of water quality regulation. The Agency states that its enforcement approach is to take a proportionate and appropriate response to each situation; that its first response is usually to give advice and guidance or issue a warning to bring an offender into compliance where possible; and that it will normally consider all other options before considering criminal proceedings.30 Penalties include: fixed or variable fines; compliance notices; restoration notices; stop notices; enforcement undertakings. The Rural Payments Agency ensures that land managers receiving payments from the EU’s Basic Payment Scheme (BPS) or a stewardship scheme adhere to cross-compliance rules in areas such as water and soil quality. It can impose penalties, such as reducing or stopping future payments.31 Natural England have a role as an executive non-departmental public body, sponsored by Defra, to advise on water quality, biodiversity and ecosystems, land management and farming issues.32 The Drinking Water Inspectorate offers independent oversight to ensure that water companies in England and Wales supply safe drinking water that meets the standards set down in law.33 The UK Water Framework Directive Technical Advisory Group (UKTAG) chaired by the Environment Agency brings together conservation and environmental agencies to provide advice on the scientific and technical elements of the WFD, such as monitoring progress and setting objectives.34

Air Quality

10.There are a series of EU Directives that focus on air quality,35 which concentrate on key pollutants including nitrogen oxides and ammonia. The Directives are transposed by secondary legislation, supported by guidance, such as on the management of animal waste on farms to reduce ammonia emissions.36 Air quality is monitored across the UK by the Environment Agency.37 The Government has developed plans setting out UK air quality standards and for reducing levels of health-threatening pollutants, especially nitrogen oxides.38 However, it is subject to infraction proceedings for breaching the EU Ambient Air Quality Directive for failing to produce an adequate National Plan to reduce nitrogen dioxide pollution.39 Nitrous oxide, a type of nitrogen oxide, is also treated as a greenhouse gas and monitored by the Committee on Climate Change.40 Members of the public and organisations can take legal action in UK courts or report the UK Government to the European Commission for breaches of both water and air quality Directives.41 For more detail on Air Quality Directives see Annex 3.

1 Rachel Salvidge, Tackling Water Quality at Source, ENDS Report, (26 October 2017).

2 See for example: BBC News, England bathing waters improving, Defra claims, (5 November 2015).

3 Rachel Salvidge, EA: Potential threats to water quality include fracking pesticides’, (19 February 2018).

4 See for instance: British Geological Survey, Predicting the arrival of peak nitrate concentrations at the water table, (accessed 21 July 2018); BBC News, Scale of ‘nitrate timebomb’ revealed, (10 November 2017).

5 Nitrogen oxides refer to a group of gases made up of varying amounts of oxygen and nitrogen molecules. The two most common and hazardous nitrogen oxides are nitric oxide and nitrogen dioxide, while nitrous oxide is a powerful greenhouse gas. See: Scottish Environment Protection Agency, The chemistry of air pollution, (accessed 7 August 2018).

7 See Defra, State of the Environment: Air Quality, (February 2018), p 7. It discusses “nitrogen disposition” and “acid disposition” whereby nitrogen (e.g. ammonia and nitrogen oxides along with other pollutants) when making contact with water, soil or plants can lead to deleterious effects. See also: Defra, Biodiversity 2020: A strategy for England’s wildlife and ecosystem services Indicators, (July 2018), pp 145–147.

8 See United Nations, 17 Goals to Transform Our World, (accessed 21 September 2018). See also House of Commons Library, Sustainable Development Goals, (November 2016).

9 See: European Commission, Agriculture and rural development, (accessed 21 July 2018).

10 We covered these issues in EAC, The Future of the Natural Environment after the EU Referendum, (HC 599; January 2017), pp 15–18.

11 See Professor Penny Johnes NO30026 for an explanation of how gaseous, water and soil-based forms of nitrogen interact with each other, such as the acidification of water from ammonia and nitrogen oxides.

12 See: N O G Jorgenson, Organic Nitrogen, in Gene E Likens (Ed), Encyclopaedia of Inland Waters, (2009), pp 832–851.

13 Professor Johnes (Q11).

14 David Crohn, Nitrogen mineralization and its importance in organic waste recycling, (2004).

15 See for example: P.Cabello et al., ‘Nitrogen Cycle’ from Moselio Schaechter (Ed.), Encyclopaedia of Microbiology, (2009), pp 299–321. See NFU NO30012.

16 Nitrogen oxides are a group of seven gases and compounds composed of nitrogen and oxygen. The two most common and hazardous nitrogen oxides are nitric oxide and nitrogen dioxide. Nitrous oxide, commonly called laughing gas, is a greenhouse gas that contributes to climate change.

17 Professor Penny Johnes NO30026.

18 For eutrophication, its causes and consequences for ecosystems see: Chislock, M. F et al, Eutrophication: Causes, Consequences, and Controls in Aquatic Ecosystems. Nature Education Knowledge, (2013), vol. 4, no. 4, p 10; European Environment Agency, Eutrophication, (accessed 21 May 2018): National Ocean Service, What is eutrophication?, (accessed 21 May 2018).

19 For the symptoms of methemoglobinemia see: Lorna Fewtrell, Drinking-Water Nitrate, Methemoglobinemia, and Global Burden of Disease: A Discussion, Environmental Health Perspectives, vol. 112, no 4, (2014), pp 1371–1374; Sally Bradberry, Complications of poisoning: Methemoglobinemia, Medicine, vol. 40, Issue 2, (February 2012), pp 59–60.

20 Generally, nitrates are the main pollutant in ground and coastal waters, while phosphates are the main pollutant in rivers. In 2015, 37% of groundwater bodies in England were failing because of nitrate and 69% were at risk of failing mainly because of nitrate. See Defra NO30049.

21 Around 88% of ammonia emissions in the UK come from agriculture. See: Defra, Code of Good Agricultural Practice (COGAP) for Reducing Ammonia Emissions, (July 2018).

22 The agriculture sector dominates emissions of nitrous oxide: emissions from agricultural soils in 2016 account for 53% of total UK emissions, and other agricultural sources add another 13%. Other important sources in recent years include road transport, other fuel combustion sources and waste processes. See National Atmospheric Emissions Inventory, About Nitrous Oxide, (accessed 15 July 2018).

23 See for example: WWF, Angling Trust and The Rivers Trust, Saving the Earth: A sustainable future for soils and water, (April 2018), who make the link between poor soil health and the loss of nutrients, such as nitrates, and organic matter into rivers and other water sources which cause pollution. See also: Environmental Audit Committee, Soil Health, (HC 180; June 2016).

24 See for example: European Commission, Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions Consultative Communication on the Sustainable Use of Phosphorus, COM(2013) 517 final, (July 2013), p 2.

25 See for New South Wales Department of Primary Industries (Agriculture), Why phosphorous is important, (accessed 1 June 2018).

26 Fien Amery and Oscar Schoumans, Agricultural phosphorus legislation in Europe, Merelbeke, ILVO, (2014), p 1. See also Dr Paul Kay, University of Leeds NO30006.

27 See Natural Environment Research Council, Phosphorus river pollution traced back to sewage, (2010); Environment Agency, The State of the Environment: Water Quality, (February 2018), p 5; and Environment Agency, The State of the Environment: Water Quality, (February 2018), p 5; M E Stuart and D J Lapworth, Macronutrient status of UK groundwater: nitrogen, phosphorus and organic carbon, Natural Environment Research Council, (2016), p 9. The latter note sources of phosphorous include; agricultural soils (arable and grassland); septic tanks and leaking sewers; water treatment works; leaking water pipes (orthophosphate dosing for plumbosolvency); earth-lined slurry lagoons and manure heaps.

28 Professor Johnes Q19 and Q34 and Professor Jarvie Q19.

29 See: European Commission, The EU Water Framework Directive - integrated river basin management for Europe, (accessed 16 July 2018).

30 For a general overview of the EA’s enforcement and sanctions policy see: EA, Environment Agency enforcement and sanctions policy, (May 2018).

31 See: Defra et al., Cross compliance 2018, (May 2018); Rural Payments Agency and Defra, Basic Payment Scheme (BPS), (August 2018).

33 See: Drinking Water Inspectorate, What we do, (accessed 20 July 2018).

34 See: UKTAG, About UKTAG, (accessed 27 July 2018). The Joint Agencies Groundwater Directive Advisory Group (JAGDAG) reviews assessments made by the agencies and comprises the Environment Agency (EA), the Scottish Environment Protection Agency (SEPA), the Northern Ireland Environment Agency (NIEA), the Environmental Protection Agency Ireland (EPA), Health Protection Agency (HPA), Department of Environment, Food and Rural Affairs (Defra), Welsh Government (WG) and industry representatives. See: UKTAG, JAGDAG, (accessed 27 July 2018).

35 For the full list of Directives see: European Commission, Air Quality - Existing Legislation, (accessed 20 July 2018).

37 See: Defra, Monitoring Networks, (accessed 20 July 2018).

38 For the most recent plan to reduce nitrogen oxides see: Defra, Air quality plan for nitrogen dioxide (NO₂) in UK (2017), (March 2018).

40 Committee on Climate Change, Reducing UK Emissions: 2018 Progress Report to Parliament, (June 2018), p 184 -188.

41 For example, in May 2017 the European Court of Justice ruled against the UK Government for breaches of the Urban Waste Water Directive. See: IEMA, ECJ rules against UK for wastewater failings, (May 2017).

Published: 22 November 2018