Materials to Land: Supporting better regulation and sustainable soil use decisions

Recovery of appropriate waste and waste-derived materials, including biosolids, to land is an important source of nutrients and soil improvers, reducing costs to both industry and land managers, while improving resource efficiency. This is an increasing market, with a widening diversity of source materials being used to create these products, but they may also present challenges in relation to their composition, for instance by containing potentially toxic elements. It is thus important that the landspreading of these materials does not lead to unacceptable risks to human health and the environment.

The chemical composition of soils varies greatly due to inputs from both natural (geological) and contaminant (anthropogenic) sources of elements. Therefore, there are substantial concentration variations over the landscape, as demonstrated by the large systematic national soil geochemistry datasets held in BGS, from NERC funded science programmes. These highlight how some rock formations give rise, entirely naturally, to soils with elevated concentrations of elements such as lead, cadmium and nickel in specific areas. There are also clear anthropogenic influences, with urban centres and historical mining areas often having elevated concentrations of these elements, amongst others.

We have established, with project partners, that the soil data present opportunity to support informed decision making at multiple scales, through mapping predicted of soil chemical composition between the sampled sites. Being able to predict at unsampled locations is important to consider what the likely soil composition may be at a candidate site for application of these organic materials. This approach would provide information not only on predicted concentrations, but an indication of the confidence that any given prediction has attached to it (using the science of geostatistics). We will demonstrate this for England, using selected chemical elements.

This methodology is particularly applicable to the regulator (Environment Agency (EA), where a paucity of this type of information is currently creating a policy challenge. The soil predictions will be examined at a local scale to support EA decisions on licence applications, but can also be used by farming businesses, and sellers, to make a preliminary assessment to help inform their decisions on the likely suitability of land to receive a given material, and more general protection of soil quality. The National Farmers Union are also project partners, to help produce outputs which will help farmers.

On a regional/national scale these maps will benefit the EA and the Food Standards Agency in making strategic, regional, assessments of soil chemical quality and any risks these may present to human and environmental health, now or under plausible scenarios which can be tested with these mapped outputs.

Sustained inter-organisational and inter-personal communication will ensure successful project progress and these effective networks will be continued post-funding. We will ensure wide visibility and uptake through engaging with relevant bodies within our project partners, and with other representative bodies with which they have links. Integration of feedback from both those with regulatory responsibilities and representatives of the farming sector will support outputs which are comprehensible to farming stakeholders. We have ensured sustainable web-hosting of outputs beyond project funding, and outputs will be available free-of-charge. The methodology will serve as an exemplar across the UK's devolved administrations and beyond, as well as for other contaminants which are of concern and for which data becomes available.

KEYWORDS: soil; biosolids; contaminants; regulation; farming.

Our largest impact shall be through substantial improvement in the soil quality information which is used by the Environment Agency to understand local threats to soil quality from application of waste-derived materials: this will be a very frequent, routine application of GIS mapping outputs from this project in the Operational directorate in-house software, and used on each licence application to apply waste-derived materials to land. The particular benefit is that the probabilistic approach to the mapping will provide consistent information across England and support evidence-based decision making at the local scale, supporting the Environment Agency's commitment to equitable approaches.

More strategic impact will be delivered through the use of the data to support the Environment Agency Evidence Directorate and Food Standards Agency Food Policy Section on a regional and national basis. These data will help strategic decisions about where waste-derived materials beneficial properties will not be compromised by application of these materials as alternatives to conventional (inorganic) fertilisers. It will also allow identification of regions where geogenic, or anthropogenic, sources of potentially harmful chemical elements in soil could already preclude application of these materials to land in order to protect environmental quality and food safety. This meets a policy need identified by the Environment Agency (see LoS). These outputs will also support a key knowledge gap identified by the Food Standards Agency (see LoS), who need more evidence to understand whether geographically defined controls on use of offal from some regions should be implemented: the mapping outputs will guide that process and directly impact that aspect of food quality.

The participation of these project partners will enable these impacts to be delivered, as their contribution to project design and commitment to full participation in the project ensures that the mapping outputs will be suitable for the policy challenges which were originally identified. More effective regulation is a key driver for the public sector, as increasing efficiencies are required, and this project will support that outcome for the Environment Agency in this specific area.

The invaluable perspectives and input of the agricultural sector will ensure that impact is achieved beyond the regulatory sector. We will achieve this through working with the National Farmers Union (NFU). These farm business perspectives are an integral component of the project's design as they will help frame project outputs. Delivering comprehensible, yet meaningful, results will draw on best practice in communication of risk, such as used by Lark, Ander and colleagues in recent work in the north of Ireland, applying verbal and numerical scales of uncertainty of likely outcomes to support farm-to-regional scale advice. Here we will further develop and improve that approach through the direct interactions with the NFU, who will benefit from the project through access to information which is currently inaccessible (despite generally being collected from farmland soils) and which is consistent with that used by the regulator to make decisions.

The new mapping outputs developed will be made available to all through existing NERC and BGS mapping platforms, such as via the web-portal UK Soil Observatory, to improve data-legacy. In addition to this we will pursue impact through giving presentations at relevant meetings involving project partners, and more widely through exploiting synergies with projects, e.g. the Magnesium Network (Jan 2016- Dec 2019; BBSRC-NERC SARIC research grant BB/N004280/1, see Track Record), which has a different premise and wider context, but considerable synergies in terms of links with the agri-business stakeholder community.