UK: Topsoil geochemistry

There is no simple answer for ‘how polluted is somewhere’, since both natural and artificial processes have resulted in chemical variations within the soil. The survey didn’t measure every type of environmental pollutant, only inorganic chemical elements.

The element maps for topsoils show areas with higher element concentrations relative to their surroundings, but such areas are not necessarily contaminated. We have not displayed the  survey data relative to any guideline levels since there are only a few official Soil Guideline Values (SGV).

The data will provide a resource for research into the effects the soil chemical environment may have on people’s health, though this is the specialist area of health professionals and researchers and not directly within the remit of the BGS.

For answers to health-related questions, please contact your local authority or your local Health Protection Agency’s health protection unit.

There are many sources of chemicals in the environment; some are natural and some introduced due to human activities.

This survey detected the background, geological signature that we term the natural baseline geochemistry. Even this can display lots of variation in the concentrations of some chemical elements. A few examples of human activities that can change these background levels include:

• industry
• construction projects
• traffic
• agriculture

We make information on the environment available so that individuals and organisations can make informed decisions. There may be instances where local authorities may wish to do follow-up studies on the basis of the data.

No. This survey data is intended to measure and map the background concentrations of a range of inorganic elements in soil. It is not intended to be used as a site-specific tool or to replace site investigations. However, it can be used to set the wider context around a more detailed site investigation for a specific site.

This survey is designed as a regional-scale, baseline survey and not for assessment of single sites. However, if you wish to look and assess the data in your area, you can download maps or use the interactive viewer.

The sample taken in your area would give an indication of the level of many elements in the soil and, since the data is accurate, would allow you to compare this point to the rest of the range of data across your region. However, due to the complex history of many urban soils (due to the intensity of their use) there are often big differences in the levels of elements over a short distance. Therefore one data point in a garden is not enough to give a true reflection of the range of levels of elements over the whole area of the garden.

A kilogram (kg) is one thousand grams. A milligram (mg) is one-thousandth part of a gram so a concentration of 1 mg/kg copper, for example, in a soil sample means that a kilogram of soil contains one milligram of copper. This could be compared to approximately 5 grains of sugar in a 1 kg bag.

It is possible to be exposed to small amounts of soil, for example, on food or in the air we breathe. It is also possible to directly eat soil accidentally. Young children are more likely to do this since they have more regular hand-to-mouth contact with soil during play.

For answers to health-related questions, please contact your local authority or your local Health Protection Agency’s health protection unit.

Please contact our enquiry service:

enquiries@bgs.ac.uk
Tel: 0115 936 3143