A lack of awareness around wider legislation governing topsoil, particularly surrounding contamination testing, is facilitating the use of potentially contaminated product on landscaping projects across the country, warns a leading soil supplier.
The British Standard for Topsoil – BS 3882:2015 – outlines parameters for a variety of horticultural properties that topsoil must meet to be deemed compliant, including texture, pH and NPK values (ref: Table 1). However, there are no set criteria for contamination testing as it is dependent on the proposed end-use of the topsoil at the recipient site. Instead, Notes 3 and 4 of Table 1 refer the user to other references including the Environment Agency’s Contaminated Land Exposure Assessment model and the Chartered Institute of Environmental Health. However, although there is a mandatory requirement to test soils for contaminants, there is no definitive list that should be tested for, or what thresholds are deemed acceptable.
A contaminated land exposure assessment aims to assess the risk to human health from contaminated soil. However, many contractors and testing laboratories are simply not aware of the need to undertake contamination testing on BS 3882:2015-compliant topsoil, and risk putting potentially contaminated soil into a number of at-risk scenarios, including gardens and schools.
The issue is particularly prevalent with recycled topsoils, warns Tarmac’s Topscape team.
Sarah Bland, Technical Sales Manager at Topscape, comments: “While a British Standard label on a topsoil product may, for many contractors, be interpreted as confirmation the soil in question is completely safe and suitable for use in all applications, that is not necessarily the case.
“There is no doubt that the British Standards for Topsoil is an essential tool for eliminating the use of low-cost and potentially hazardous recycled soils, whose provenance is incredibly difficult to prove. However, given the broad scope of the standard, the level of screening can only go so far. As such, we would strongly urge contractors to ensure that the topsoil supplier (or the testing laboratory) has included contamination testing when purchasing any topsoil, and particularly when using recycled soils. Doing so will give them the full picture as to the quality of their soil, and ensure they can undertake projects safe in the knowledge that the soil they’re using will provide the best possible growing conditions, without any of the risks linked to recycled products.”
Sarah concludes: “Many reputable topsoil suppliers – including Topscape – ensure their products are fully BS-certified, including a comprehensive list of industry-recognised potential contaminants. For contractors keen to understand the British Standard for Topsoil and Contaminated Land Exposure Assessments in more detail, Topscape’s technical sales team are able to offer expert advice on how to ensure any project – regardless of application – can be undertaken safely and correctly.”
All topsoil from Tarmac’s Topscape team is tested to BS 3882:2015 by a fully independent soil science testing company.