Nitrates in the Solent – a brief guide

Nitrate pollution in the Solent impacts any development with overnight accommodation and has brought many residential development projects to a standstill. Developers, construction companies and home-buyers are becoming increasingly frustrated so we at Foot Anstey have decided to do something about it. We have set up the Nitrates Stakeholders' Forum in order to gather feedback from the public and private sectors whilst pushing for a resolution.

We're also determined to raise awareness of the issue and help others understand it, so we've assembled this guide which answers some of the common questions and concerns we hear about the nitrates problem.


Why are nitrate pollution levels in the Solent a problem?

The Solent water environment is one of the most important for wildlife in the United Kingdom. It has various protected designated habitat sites including Special Protection Areas, Ramsar and Solent Maritime Special Area of Conservation.

Nitrates make their way into the water from our use of the surrounding land. Agricultural sources such as the use of fertilisers accounts for about half of the total loading in the Solent. Other sources are urban such as waste water from housing and there is also a significant proportion from unknown sources.

When the amount of nitrates that enter the water environment reaches a certain level this causes eutrophication. This is when green algae mats grow depleting oxygen in the water. Consuming this water is harmful to human health and upsets the biodiversity and ecosystems of the water environment. This has been a concern for a while.

What advice on nitrates has natural England given councils in the Solent region?

In June 2019, Natural England sent advice to all Local Planning Authorities in the Solent region setting out the guidelines for new development sites. They advised that whilst there is uncertainty at this time as to whether new residential development will further deteriorate the protected sites, one way to address the issue would be for new development to achieve nutrient neutrality. This would mean ensure the development does not make the nitrates loading in the Solent any worse.

The Conservation of Habitats and Species Regulations 2017 (HRs) sets out strict systems for the protection of European sites and European Protected species. Therefore the local planning authorities have to ensure they only grant consents that comply with Natural England's advice or face the possibility of legal challenge.

Natural England set out in their advice a method for calculating nitrate neutrality. This compares the difference between the proposed use applied for against the pre development levels. Any nitrogen loading must be offset in perpetuity via mitigation methods.

What is the EU's role in the nitrates issue?

Natural England's advice to local authorities is based on its interpretation of European court decisions.

Last year was a busy year for the Court of Justice of the European Union (the ECJ) with various cases on the interpretation of the EU Habitats Directive, particularly Article 6.

There are three cases in particular which relate to the nitrates issue, two from Ireland and one from the Netherlands.

The first of the Irish cases in April 2018 looked at the installation of a cable near a river and the steps needed to stop the resulting pollution damaging the habitat of a protected pearl mussel. The second in July 2018 involved a wind turbine proposal which was likely to cause a loss of habitat for hen harriers.

In the first case the ECJ said that Appropriate Assessments (AAs) had to provide a "full and precise" analysis of the project's impact on conservation in the area. In the second, it held that mitigation measures would have to guarantee "beyond reasonable doubt" that the hen harrier's habitat would not be adversely affected by the development.

By November 2018 the ECJ was dealing with the Dutch nitrates case, comprising two challenges by conservation groups against permits granted to farms in special areas of conservation affected by nitrates.

The ECJ decided that:

  1. There has to be a thorough analysis of the scientific evidence contained in the AA
  2. "There should be no reasonable scientific doubt as to the absence of adverse effects of each plan or project on the integrity of the site concerned" before giving the farm a permit.

So conservation measures or any other mitigation need to be certain in their benefits, and need to apply directly to the conservation area affected rather than provide an environmental benefit elsewhere. This is the origin of Natural England's advice to planning authorities.

How does nitrate offsetting work?

An important part of this compliance is for there to be an Appropriate Assessment (AA) carried out when the development proposal is considered to increase nitrogen loading into the protected sites. The use of the nitrogen budget will calculate the loading and where this is not nitrate neutral then other nitrate mitigation will be required.

Where a development does not achieve nitrate neutrality then planning should not be granted.

Natural England has produced a number of suggestions for mitigation. To date local planning authorities and developers are still working through how the mitigation could be secured such that it would be satisfactory to Natural England.

Can a Grampian Condition help a development go-ahead?

Some of the Local Planning Authorities have considered the use of Grampian Conditions to the effect that the dwellings would not be occupied until a mitigation "package" addressing any additional nutrient input as a result of the development has been submitted to and approved by that Local Planning Authority.

Whether that is suggested because the developer does not have a mitigation plan quite resolved or the local authority does not have any mitigation measures in place will determine the decision making process and in some circumstances that may be acceptable for a developer. However, in the event such mitigation measures have no end date to be completed then with such uncertainty the precautionary approach is to refuse consent, whether that be by the local planning authority or a planning inspector.

Could nitrate pollution affect development elsewhere?

56% of England is classed as a 'Nitrates Vulnerable Zone,' which means Natural England could ultimately issue similar advice to local authorities in those areas too.

I need advice about a development in the Solent affected by nitrates – can you help?

Of course. Several Foot Anstey specialists have contributed to our work on the nitrates conundrum and you are welcome to contact them with questions relating to their area of expertise:

Key Contacts