Research

A nation that destroys its soil destroys itself

Brownfield

The importance of soil

Soil is one of the UK's most precious resources and yet our soils are under threat. Since industrialisation, we have been taking carbon out of the soil in the form of food and textiles and not replacing it at the same rate. To maintain fertility, we use artificial nutrients instead, leaving the soil with a carbon deficit and insufficient water holding capacity. The missing carbon in our soils has ended up in the atmosphere, contributing to climate change and increasing the probability of extreme weather events, such as the 2014 floods in Somerset and the 2007 floods in Carlisle and Yorkshire.

Why we need to regenerate soil

Degraded soil is less capable of delivering essential ecosystem services: food production, provision of public health and wellbeing, flood mitigation and carbon storage. According to the Natural Environment White Paper, all UK soils need to be managed sustainably including successfully tackling degradation threats by 2030. In addition, regenerating brownfield land may also help improve public health and community wellbeing, as communities with large amounts of brownfield tend to have poorer health outcomes.

Benefits of maintaining soil organic carbon

Healthy soils that have sufficient soil organic carbon (SOC) are more resilient to erosion. By absorbing many times its weight in water increasing SOC could contribute to flood mitigation after extreme rainfall events and store water during frequent or severe droughts. Soils are predicted to become warmer which could likely lead to increased soil respiration, making them drier and less stable during extreme weather. This can be counteracted if SOC levels are maintained and enhanced.

The National Adaptation Programme (NAP) lacks specific plans to investigate how to enhance SOC and hence increase its capacity to store water (potential increases in water holding capacity range from 3% to 20%); and its ability to be absorbed by the land to replenish acquifers.

A recent House of Lords report on the Bioeconomy identifies 30 million tonnes of organic wastes produced each year in the UK, which have come from the land but are currently not returned to it. Finding sustainable ways to raise SOC levels using organic wastes is an opportunity that must be explored by soil engineers and scientists in order to safeguard SOC and ensure soil has maximum flood and carbon mitigation potential.

References
  1. EU Soil Report 2012
  2. National Environment White Paper 2011
  3. Bambra C, et al. (2014) 'Healthy land? An examination of the area-level association between brownfield land and morbidity and mortality in England'. Environment and Planning A 46(2)
  4. National Adaptation Programme 2013
  5. Waste or Resource? Stimulating a bioeconomy, House of Lords, Science and Technology Select Commitee, 2014

Living near large areas of brownfield land can damage health

People living near brownfield sites are significantly more likely to suffer from poor health than those living in areas with little or no brownfield land, according to new geographical research. The findings by Durham University suggest that the regeneration of brownfield land should be considered as a policy priority for Local Authority public health teams. The research – the first to examine the link between brownfield land and health in England – shows that brownfield sites could be a potentially important and previously overlooked environmental influence on health.

People living near brownfield sites are significantly more likely to suffer from poor health than those living in areas with little or no brownfield land, according to new geographical research. The findings by Durham University suggest that the regeneration of brownfield land should be considered as a policy priority for Local Authority public health teams. The research – the first to examine the link between brownfield land and health in England – shows that brownfield sites could be a potentially important and previously overlooked environmental influence on health.

Brownfield land is previously used or derelict land that may have real or perceived contamination problems and that requires intervention to bring it back into productive use. The Homes and Communities Agency estimates that there is around 62,000 hectares of brownfield land in England alone.

Durham University researchers found that local communities with large amounts of brownfield land in England had poorer health outcomes, including limiting long term illness. Electoral wards with large areas of brownfield generally had worse health compared to those with no brownfield or only small amounts.

While the hazardous effects of brownfield land with contaminants are well known, researchers suggest that, regardless of contamination, brownfield could have wider negative impacts on the general health of communities. They say further research is needed to find out which health effects play the greatest role.

The research is published in the academic journal Environment and Planning A.

Professor Clare Bambra, lead author of the study from Durham's Department of Geography, said: "Our study shows that local authorities and central government need to prioritise the remediation and regeneration of brownfield land to protect the health of communities."

Co-author of the study Dr Karen Johnson, from Durham University's School of Engineering and Computing Sciences and Institute of Hazard, Risk and Resilience said: "Brownfield has potential negative impacts on people's sense of wellbeing and this could be psychological or toxicological, or both.

"Roosevelt said that 'a nation that destroys its soils destroys itself' and I agree. Land is important to us and it comes as no surprise that brownfield has a negative effect on people's health."

The study used data on brownfield land from the 2009 National Land Use Database, which encompasses around 72 per cent of previously developed land across England. Health data for the study was taken from the 2001 English Census, and data on premature death was used from the Office for National Statistics from 1998-2003.

The brownfield and health data were mapped onto ward-level data to calculate the percentage of brownfield land within each ward.

After controlling for variables such as age, sex, economic background as well as other forms of environmental deprivation, wards with large areas of brownfield had a 15 per cent increase in ill health, including a 14 per cent increase in limiting long term illness, compared to wards with little to no brownfield.

Co-author Dr Steve Robertson of the School of Engineering and Computing Sciences and Institute of Hazard, Risk and Resilience at Durham, said: "Our results suggest that brownfield land poses a problem for public health, but further research is needed to tell which health effects are most important in order to develop the most appropriate solutions."

Read the Policy Research Brief

Read the paper online (open access):

Bambra C, Robertson S, Kasim A, Smith J, Cairns-Nagi J M, Copeland A, Finlay N, Johnson K, 2014, 'Healthy land? An examination of the area-level association between brownfield land and morbidity and mortality in England'. Environment and Planning A 46(2)

To see the maps produced from this study visit the Institute of Hazard, Risk and Resilience Blog

First ROBUST Public Field Trial Begins

The ROBUST project has begun its first public field trial, testing a new technology for improving soil health. A mix of compost along with recycled minerals has the potential to improve the natural defences of the soil against contaminants, and was added to the Old Pygall Coachworks site located in Easington Colliery in County Durham. The site was once used as a lorry garage and a coach park which has left some manmade pollution in the soil. This trial will be the first to reveal whether the technology can be used to regenerate land with contaminants left from previous uses.

Where they are contaminated, the soil of brownfield sites may contain more than one type of contaminant, for example a combination of heavy oil and diesel fuel along with toxic metals. The ROBUST technology has the potential to harnesses waste minerals to break down or immobilise both types of pollutants in the soil. Manganese and iron oxides form part of the soil's natural defence mechanism against industrial pollutants and the ROBUST technology makes use of sources of these minerals that would otherwise be classed as waste.

Where do the recycled minerals come from?

The recycled minerals are from the water treatment industry and are a residue from 'upstream' filtration processes used to produce clean drinking water. They have nothing to do with sewage sludge, which comes from 'downstream' treatment of waste water.

What do the minerals do to the soil?

Generally, these minerals do one of two things to contaminants in soil: they adsorb them, which makes them stick to the surface of the material and prevents them from moving through the soil or the minerals oxidise contaminants, breaking down pollutants into harmless by-products. Immobilising toxic metals such as lead prevents them from entering into the groundwater. Iron oxide is particularly good at adsorbing arsenic and biogenic manganese oxides have been found to absorb toxic metals completely.

How will the trial involve the local community?

The site will be monitored over time to find out if the ROBUST technology is successful in improving the health of the soil. This soil trial will include involvement from the local community in order to understand their perspective on the land and involving them in developing ways to help regenerate it over time. The idea is that health of the land and the communities that live on the land go hand in hand, so regeneration can help improve people's well-being and the health of the land as a whole.