Report on investigating the risk of lead in the soil of the Great Longstone village allotments

Soil Samples taken in the Parish Council's allotments, as part of a routine risk assessment, have come back with levels that are significantly higher than the recommended safe levels. It has been recommended by Environmental Health @ DDDC that a more detailed investigation should be undertaken.

Summary

“Lead (Pb) is a metallic element naturally occurring in trace amounts in the Earth’s surface environment with concentrations in rocks averaging 15 mg/kg. Generally, acid igneous rocks (e.g. granites) are higher in Pb than basic ones (e.g. basalts) and concentrations in sedimentary rocks are variable with up to 70 mg/kg in some limestones. With a low melting point, Pb ore minerals are readily smelted and the metal is easily worked. Lead therefore has a long history of use in human activities. In England there are a number of historical lead mining areas (e.g. the Derbyshire Peak District) where there is a legacy of Pb contamination caused by mining and associated activities. Biologically it is considered as a non-essential element and toxic to man and animals through the food chain and soil dust inhalation or ingestion.” [i]

Lead can be absorbed into the body though various routes, including through food. Crops absorb lead at different rates, and some have higher concentrations in skins, that can be removed.

In January 2025 a sample of soil from the Parish Council allotments was sent for testing. The results came back at the beginning of April and the level reported was more than 15 times higher than current UK recommended maximum level for allotments, though this is lower than the average expected in “areas of mineralisation”, which includes the former lead mining areas of the Peak District.

The laboratory results, for a soil sample collected from various parts of the allotments, was above 1,250 milligrams per kilogram (mg/kg). The exact level is not known as this is the maximum level that the laboratory is licenced to test to.

UK guidelines suggest a maximum level of 80 mg/kg (previously the figure was 450 mg/kg). However, the “Technical Guidance Sheet on normal levels of contaminants in English soils[ii]” explains that the Peak District is an area of “Mineralisation” and that tests conducted on 347 samples from “Mineralisation” areas produced an average result of 2,400mg/kg. This guidance explains that test results should be compared with the “average” for the area type.

A study in Newcastle, where allotments averaged around 550 mg/kg, found that levels of lead in allotment holders was no higher than in other people living in the same area.

Statutory Guidance, on dealing with land contamination, was produced by the Department for Environment, Food and Rural Affairs (Defra) in 2012, based on legal frameworks created by Environment Act 1995 and Part 2A of the Environmental Protection Act 1990[iii]. In this Parish responsibility for deciding if land is contaminated lies with Derbyshire Dales District Council.

Derbyshire Dales District Council’s Environmental Health Department have recommended that the allotments should be closed whilst further tests are undertaken.

The Parish Council will hold a special meeting in the village hall at 7pm on the evening of Wednesday 16^th April to discuss this issue.

Allotment holders will be invited to attend the meeting and will have the opportunity to take part in the public session.

Acknowledgements

This report initially drew heavily on information on the “Safe Soil” website[iv].

The “Safe Soil” website refers extensively to the study – An apple a day? Assessing gardeners’ lead exposure in urban agriculture sites to improve the derivation of soil assessment criteria[v] undertaken by the Northumbria and Newcastle Universities on behalf of Newcastle City Council.

Background

Lead can be harmful to human health if absorbed into the body. The three main routes of entry are:

Inhalation (airborne contamination)
Absorption through the skin (i.e. contact with contaminated soil/dust)
Ingestion (i.e. eating produce contain a high level of lead)

Levels of airborne contamination has been reduced since lead was banned from being used as an additive in fuel. Other sources of airborne pollution could include industrial processes and contaminated dust.

Absorption and Ingestion will both be as a result of ground contamination from lead, which is a known issue throughout the country.

Lead poisoning in adults can be difficult to spot with symptoms that are predominantly emotional and mental in nature. In young children it can be particularly serious with the potential for a long-term impact on development.

Lead contamination is usually associated with metropolitan areas, specifically those with a history of industrialisation and/or areas that suffered from extensive bombing during the Second World War.

There is little evidence of research having been undertaken in rural areas.

The industrial past of Great Longstone, as in many villages in the immediate area within this part of the National Park, is rapidly being forgotten. Within the Parish there are a number of mining related scheduled monuments, including the Cackle Mackle lead mines on Longstone Moor and numerous shafts and worked lead rakes.

It is thought that lead mining in this area dates back to the Roman period and anyone who walks in the fields surrounding the village, particularly to the north towards Longstone Edge, will easily find signs of ground disturbance and the remains of “spoil” piles, which show ample evidence of relatively recent mining activity.

Anecdotal evidence suggests that local farmers manage their use of some fields to reduce the risk of accidentally poisoning animals through contaminated grass. Over the years a number of horses have been known to have died locally from lead poisoning and local farmers have lost calves to suspected lead poisoning.

It has been suggested that some areas that are now within the main part of the village may have been used by previous generations to “wash” lead ore, though there are no known documented records of this.

Great Longstone Parish Council Allotments

It is thought that the village has had allotments at their current site since at least the 1950s. Previously there have also been allotments on Station Road and in “The Meadows”, on sites that now contain housing.

The allotments, and the neighbouring plot that became “West Green”, were donated to the Parish Council in around 2000, having previously been owned and managed privately.

In 2001, shortly after the Parish Council took over the management of the allotments, guidance was sought from Derbyshire Dales District Council and the minutes of GLPC Meeting on 9^th January 2002 recorded that:

“A letter from DDDC was read out stating that it would appear unlikely that the soil in the allotments would contain high concentrates of lead[vi].”

The minute went on to say:

“They recommended testing different vegetables if the Parish Council felt it necessary. The Councillors resolved to ask the Clerk to ask for the vegetables to be tested.”

The following month the Clerk reported that testing would cost £80 per plant. Members felt that this was too expensive for the Council to pay (at the time rents were less than £10 per year) and the Clerk was instructed to ask Allotment Holders if they would like to do their own tests[vii].

In addition to being in Parish Council minutes this was more extensively reported in the March 2002 edition of the community magazine “Under the Edge”. [viii]

At around the same time an Allotment Holder (who still lives in the village) carried out their own tests with “Reagent Strips” and these came back as being negative for Lead.

Whilst no one had raised this as an issue the Council decided in November 2024, as part of its own routine risk assessment processes, to investigate this again.[ix]

Testing

It was reported to the Council in November 2024 that there appeared to be two main types of tests[x]:

Reactive Strips
Laboratory testing

Reactive Strips are relatively cheap but will only give an approximate level (i.e 0, 100mg/Kg or 400mg/Kg.

Laboratory testing seems to start at around £100 per soil sample. If a soil sample is taken is one sample enough or should multiple samples, from different parts of the allotments, be analysed. The Council decided to commission Soil Tests and the Clerk was tasked with arranging this.

It was found that Carrs Billington in Bakewell act as agent for Yara UK’s Lancrop Laboratories. They recommended that given the small size of the site that it would be sufficient to take a submit a single sample that consisted of soil collected from across a number of plots.

Results

With the lead level the laboratory can only say that it is “above” 1,250mg/kg. Their equipment is not rated to measure samples that are higher than this level.

Apparently, the Ph (at 7.7) is fairly high, which might reduce the update of lead into plants.

What is lead poisoning and what are the symptoms?

According to a Penn State University report: “Serious human health risks, particularly for children under 6 years of age, are associated with lead poisoning. Low-level, chronic exposure to lead in contaminated residential soil can cause several developmental and behavioural problems in children. Among these are reduced IQ and attention span, hyperactivity, impaired growth, learning disabilities, hearing loss, and insomnia. Once absorbed by the human body, lead is extremely difficult, if not impossible to remove. Therefore, not only is prevention of lead poisoning the best cure, but it may be the only cure.”

What are the acceptable levels of lead in soil?[xi]

In the UK the Category 4 Screening Levels (C4SL) for Lead have been published. (Lead concentrations in soil are measured in parts per million or milligrams per kilogram (mg/kg).)

Allotments 80mg/Kg
Residential (with consumption of homegrown produce) 200mg/Kg
Residential (without consumption of homegrown produce) 310mg/Kg
Commercial: 2,330mg/Kg

The previous (and now withdrawn) figures, known as the UK soil guideline values (SGV) where:

Residential/Allotments 450mg/Kg
Commercial 750mg/Kg

The US Environmental Protection Agency uses a threshold of 400 mg/Kg for residential soil.

It is reported that the C4SL figures are likely to be conservative and a lot depends on what is grown, how much is consumed and other factors such as reducing exposure to dust by washing hands and not carry it from clothing, shows and tools into cars or homes.

Environmental Protection Act 1990

The “UK Health Security Agency” have published a detailed factsheet “Contaminated Land in residential settings [xii]”

Part IIA of the Environmental Protection Act 1990 requires the local authority, which for Great Longstone is Derbyshire Dales District Council, produce a Contaminated Land Inspection Strategy so that they can identify, inspect and remediate contaminated land.

On the DDDC website is says “The district council will identify historic sites that may have resulted in land contamination and may complete a site investigation either through the Contaminated Land Regime or through a planning condition. Site investigations can involve soil sampling, groundwater sampling and the assessment of ground gas. The results of these are used with a conceptual site model to identify the risks posed to human health and the wider environment.

Once land is determined as contaminated, its details are entered into a Contaminated Land Public Register. Currently no sites have been determined as contaminated within Derbyshire Dales, and accordingly there are no entries on the Public Register.[xiii] ” (Author’s emphasis).

The factsheet referenced above starts by saying:

“There is very limited data linking any health effects with land contamination in England and Wales.

Members of the public should continue to enjoy using garden space as they normally would, including grassed areas, planted areas, decking, patios and other areas of hardstanding.

Members of the public should follow normal hygiene precautions and wash hands thoroughly after working or playing in the garden or allotment, especially when in contact with soil and before handling food, drink or when smoking.

Members of the public should wash and peel any produce grown in the soil in order to remove any soil or dust.[xiv]”

Land is divided into categories, ranging from Category 1, which is land where the level of risk is clearly unacceptable (‘significant harm’) to Category 4 the level of risk posed is acceptably low. The Category 2/3 border defines the point at which land is determined as contaminated land under the legislation. It is believed that it is up to DDDC to decide on the Category that land should fall into, for land in this area.

However there generally seems to be a reluctance in the UK to carry out land assessments, possibly because

“The process of determination or not can take considerable time and has the potential to cause public anxiety over the health risks and disruption caused.”

And

“there is growing evidence (Defra 2009, 2014a) that stress-related health impacts of regulatory intervention might outweigh any health benefits of investigating and remediating land where there is only a low or hypothetical risk”.

I contacted Derbyshire Dales District Council’s Environmental Health Department on Friday 4^th and Monday 7^th April and had a call-back on the afternoon of Wednesday 9^th April. They recommended that:

That the allotments should be closed whilst further tests are undertaken
That they no longer have a Contaminated Land Officer and can offer no other help.
It is the landowners responsibility to engage a Contaminated Land (or GEO Environmental) Consultant
In areas with high naturally occurring contamination they would not automatically declare that a risk exists.
It is recommended that we also check for Arsenic and Cadmium, as these tend to occur in the same places as lead.

Areas of Mineralisation

The “Technical Guidance Sheet on normal levels of contaminants in English soils[xv]” explains that, with regards to lead contamination, England is divided into 3 main areas, being:

Urban areas
Mineralisation areas
Principal area (basically everywhere else)

The “Mineralisation” areas are those where soils have been impacted by lead mineralisation with a legacy of mining and associated activities (Peak District, North Pennines, Lake District and Mendips).

The document explains that when testing for lead contamination you should first decide which area you are in, as this will help to identify results that are a significant variation from expected levels for the area.

Tests conducted on 347 samples from the “Mineralisation” area produced an average result of 2,400mg/kg.

Is lead contamination definitely a threat?

Recent research in the UK suggests that the picture may be more complicated than initially believed.

A study published in Environment International[xvi] found some crops are more suitable for growing at sites with elevated lead – these include shrub and tree fruit – while others like beetroot, parsnips and carrots are less so.

Newcastle City Council tested the soil in its allotments and found the average lead level to be around 550mg/kg. Rather than remediating or closing the sites, the council commissioned a study to investigate whether elevated lead levels in soil were reflected in the levels of lead in the blood of gardeners, who were exposed to the lead in the ground and presumably consumed the produce they grew on it.

No elevated blood levels were found though the numbers participating in the study were in the dozens suggesting more research is necessary before the suggested limits for lead in soil are relaxed.

Northumbria University environmental geochemist Professor Jane Entwistle was co-lead on the study and said:

“U.K. soil screening guidelines are overly cautious in the context of many of our urban allotments and our research has found that how the lead is held in the soil is more important than simply the presence of lead. While some metals are more readily taken up by plants, lead remains attached to the soil as it is not a mobile element. What we therefore need to do is look at the form of the lead and natural regional variances rather than using standard guidelines that don’t recognise these differences.”

Ways to reduce exposure to lead contamination

The assumed “safe” exposure levels for allotments are based on users spend 3 hours per day working on the allotments (and therefore being exposed to soil) and eating produce daily for 6 months per year and 3 times a week for the other six months.

The guidelines are based on the assumption that in addition to eating contaminated produce allotment holders are exposed through handling soil (directly in the allotments or through poorly washed produce) and from dust that is carried into homes on shoes and clothing.

If contamination from soil & dust is a risk factor this might also apply to people such as owners of dogs who spend a lot of time walking in the local fields and whose pets might bring dust into their homes.

Research suggests that some fruits and vegetables are more prone to absorb lead from the soil with the order being:

Root vegetables (i.e. carrots)
Green Vegetable
Tubers
Fruit bushes/trees

In addition, root vegetables seem to carry larger concentrations of lead in their skin.

Guidance includes:

Carefully wash and peel vegetables
Do not give produce to anyone under the age of 6 years and limit the amount given to children older than 6 years.
Limit the number and variety of root vegetables grown
Try to keep dirt and dust out of the home (as applicable to dog walkers as it is to allotment holders).

Recommendation

That a Parish Council meeting be held, as soon as possible, to discuss this report and that allotment holders be notified of the meeting and given copies of this report, so that they can raise any comments in the public section at the start of the meeting.

Target date for a meeting is 16^th April with publication of this report by Thursday 10^th April 2025.

If it is not possible to get enough Councillors to make hold a meeting that is quorate, at this short notice, it is proposed that a Public Meeting will be held instead.

Simon Headington
Clerk to Great Longstone Parish Council
9^th April 2025

Websites used for source information
All websites were accessed on 9th April 2025

[i] https://nora.nerc.ac.uk/id/eprint/19978/

[ii] https://nora.nerc.ac.uk/id/eprint/19978/

[iii] https://www.gov.uk/government/publications/use-of-potentially-contaminated-residential-land-gardens-and-allotments/contaminated-land-in-residential-settings-factsheet

[iv] https://www.safesoil.co.uk/post/get-the-lead-out-lead-soil-contamination-is-more-common-than-we-think-and-it-can-be-dangerous

[v] https://www.sciencedirect.com/science/article/pii/S0160412018313138

[vi] https://greatlongstone-pc.gov.uk/minutes/council-meeting-9th-january-2002

[vii] https://greatlongstone-pc.gov.uk/minutes/council-meeting-20th-february-2002

[viii] https://www.undertheedge.net/2002

[ix] https://greatlongstone-pc.gov.uk/meetings/council-meeting-13-november-2024/

[x] https://greatlongstone-pc.gov.uk/wp-content/uploads/2024/11/Appendix-H-Item-12-Report-on-allotments.pdf