FREQUENTLY ASKED QUESTIONS

Why should I test my soil?

There are several reasons why anyone would consider testing their soil. Britain’s proud industrial and farming heritage has left behind a legacy of contamination. Industrial processes and activities released substances and waste products into the ground that have the potential to harm human health, including but not limited to heavy metals and petroleum byproducts. These as well as asbestos and other chemicals have also been released into the environment as a result of mining and, increasingly, in the process of living our lives - be that driving, transportation, energy generation et cetera. Our testing packages can give you peace of mind that your soil is safe - and start at just £60.


More on these follows:

  • Our Standard Contamination Suite measures levels of the potentially harmful elements that could be lurking in your soil including heavy metals such as lead, cadmium and arsenic; hydrocarbons and asbestos. It costs £150 (plus VAT). 

Click here for more on this, including a complete list of the elements included in the test.

  • Meanwhile, farming activities may have left behind remnants of pesticides deemed unsafe decades ago while the application of manure and treated sewage products may have also contributed some of the contaminants described above. The use of organochlorines as insecticides, for example, was banned in the UK in 1984 because of their high toxicity and their ability to remain in the environment, making them persistent organic pollutants. The best-known ones are DDT, aldrin, and endrin, all of which were used in agriculture. Our Basic Pesticide Residue test costs £125 (plus VAT) and covers these and dozens more.

Click here for the list in full and more details.


  • Pathogens like E.coli and salmonella are dangerous and can make us quite sick. They can come from a variety of sources including raw or improperly composted manure, irrigation water containing untreated sewage or manure and contaminated washing water. Dog, human or cat faeces is another common source. Some of these can survive for extended periods stretching to years but it is difficult to say precisely how long they will exist in soil.

Click here to see details of the Microbiology Examination, which costs £100 (plus VAT).


  • Or perhaps you are a gardener who has none of the above issues to contend with and is simply keen to improve the fertility of the soil in your growing space. For you we have the State of Your Soil test suite that provides analysis of soil pH, texture and organic matter as well as a measure of the three major plant nutrients: potassium, phosphorus and magnesium. It comes with not just results but also suggestions for improvement and costs £60 (plus VAT).

Click here for more details on this.

HOW MUCH DOES A SOIL TEST COST?

It depends on what you want to test for. Our testing packages start at just £60 and the price list in full is here:

HOW LONG DOES A SOIL TEST TAKE?

We ship kits using 1st class post and send them no later than a day after orders are received, usually the same day. The lab analysis takes five working days so depending on how quickly you send back the sample, the final analysis report should be with you in no more than two weeks.

HOW DOES IT WORK?

Once you decide which test or tests are right for you and make on order on the website, we'll send you a kit to collect a soil sample from your growing space along with instructions on how to do that. Return your sample to our lab in the provided box—the postage is pre-paid and already affixed so all you need to do is drop it off at a post office or, if there is one near you, pop it into a Royal Mail postbox. We’ll analyse your sample and send you the results, along with an explanation of the findings. Peace of mind could not be simpler.

HOW DO YOU TAKE A SOIL SAMPLE?

Collecting a soil sample for analysis is straightforward and should not take much time. We recommend using a composite sample, meaning that you collect a little bit of your soil from several areas of your growing space and from a variety of depths. Use a trowel (clean it first if it has been used in places other than the one being tested) to collect small amounts of soil - about a teacup’s worth - from 4-6 random sections of your growing space, ensuring that some are taken from a few inches below the surface.


Mix these in a clean container, removing any large stones and bits of organic matter such as large leaves, roots or worms. Use this mixture to fill the containers in your test kit. 


Please note that using a composite sampling method will allow for an accurate test of the soil but will not be able to specify where in your growing space particular elements are present so if the composite sample covers a particularly large growing space, follow-up testing may be necessary to locate more precise locations and concentrations of substances detected. Of course, if a representative sample throws up no sign of harmful elements, no follow-up testing is necessary no matter how large a growing space the sample covered.


SHOULD I TEST MY SOIL AFTER A SEWAGE SPILL? ISN'T SEWAGE SUPPOSED TO BE GOOD FOR THE GARDEN?

While it is true that waste products are often traditionally used to fertilise soil, untreated or raw sewage will do more harm than good. A lot more. Sewage can contain several elements that can leave soil contaminated, as per this Defra publication.


Sewage can include some or all of the following:

  • Metals such as lead, mercury and chromium that once present tend to remain in soil indefinitely

  • Persistent organic pollutants: PAHs (EPA 16), including Benzo(a)pyrene (BaP)

  • Furans

  • Dioxins

  • Polychlorinated biphenyl (PCBs)

  • Perfluorinated alkylated substances or polyfluoroalkyl substances (PFAS)


It is also possible that bacteria such as salmonella and E. coli that can survive in soil for up to several months can also be present. 


SHOULD I TEST MY SOIL IF MY PROPERTY HAS BEEN FLOODED?​

It depends on where the water came from and how it got to your property. If your growing space is on the banks of a river that floods, it is possible that no contamination took place (though your top soil may have been covered or even replaced by sediment when the water finally recedes so there may be some fertility issues to contend with). However, most flooding - particularly in urban and semi-urban settings occurs when storm drains overflow. At that point the water likely becomes mixed with raw sewage as well as road runoff that can contain chemicals including petroleum hydrocarbons - and these can pose all manner of issues. Chief among these a serious risk to our health.


MY PLANTS AND/OR TREES KEEP DYING - WHAT SHOULD I TEST MY SOIL FOR?​

In these situations, some of our customers opt to run a two-fold analysis of the soil to look at its fertility while also checking for any potential contamination. This is taken in by the following two test suites:


The basic State of Your Soil package provides analysis of soil pH, texture and organic matter as well as a measure of the three major plant nutrients: potassium, phosphorus and magnesium. It costs £60 (plus VAT). More info on this can be found here.


The Standard Contamination Suite measures levels of potentially harmful elements that could be lurking in your soil including heavy metals such as lead, cadmium and arsenic; hydrocarbons and asbestos. It costs £150 (plus VAT). More on this, including a complete list of the elements included in the test, can be found here.

IS SOIL CONTAMINATION DANGEROUS? WHAT ARE THE RISKS OF CONTAMINATED SOIL?​

The study of soil and its relationship to human health has been ongoing for at least a century and with it our understanding of this process continues to evolve but we know that there are three ways in which humans can be exposed to elements in the soil: ingestion, absorption via the skin and inhalation. All three are considered when government agencies and scientists try to determine how much of something is harmful.


Understanding which soil elements pose the greatest risk to our health is also the subject of ongoing study and research. There’s no disputing that the UK’s industrial heritage has left behind a legacy of contaminated land. We are descendants of a people who were at the sharp end of the industrial revolution and while this played an important part in establishing the living standards that we now enjoy, there was a darker downside as the very industrial processes and activities that made Britain one of the wealthiest nations on earth also released substances and waste products into the environment that have the potential to damage our health.


As a society we have come to generally accept that water and air pollution are damaging to our health, but we have been much slower in coming to understand – and accept – that soil contamination can have a similarly damaging impact. This is changing. A European Commission report into the impacts on human health of soil contamination sums up some of the common risks:


“Health problems from cancers (arsenic, asbestos, dioxins), to neurological damage and lower IQ (lead, arsenic), kidney disease (lead, mercury, cadmium), and skeletal and bone diseases (lead, fluoride, cadmium) are serious issues, that in many cases we have yet to address. Heavy metals and persistent organic chemicals are of particular concern. Human activity introduces heavy metals (such as cadmium, arsenic and mercury) to our soils through mining, smelting, industry, agriculture and burning fossil fuels. Our disposal of materials containing heavy metals – a long list which includes paint, electronic waste, and sewage – also contributes to the burden of heavy metal contamination. Organic chemicals are also part of our industrial legacy, and many are still widely used today.”


WHY IS NITROGEN NOT INCLUDED IN THE BASIC STATE OF YOUR SOIL TEST SUITE?​

Nitrogen is a crucial element of healthy soil that is needed for the development of leaves and shoots. Although many garden soils can run short of nitrogen, its levels fluctuate a great deal during the season making analysis of its levels in soils at any given time somewhat moot.


It is a good idea to apply organic matter to your soil every year – this will release nitrogen slowly throughout the year as it decomposes. Adding nitrogen fertilizer applications is also effective and is much quicker though does not last as long. Both inorganic and organic varieties are effective.


IS IT SAFE TO EAT FRUIT AND VEGETABLES GROWN IN CONTAMINATED SOIL?​

It really is not a good idea to consume vegetables or fruit grown in contaminated soil. Depending on the substance, the risks can be grave because produce from contaminated soil can take up the harmful elements and these can then end up getting stored in our organs prompting potentially serious health problems. These include cancers (arsenic, asbestos, dioxins), neurological damage and lower IQ (lead, arsenic), kidney disease (lead, mercury, cadmium) and skeletal and bone diseases (lead, fluoride, cadmium) - and these are just the ones we know about.


WHAT ARE THE SIGNS THAT MY SOIL MAY BE CONTAMINATED?

Humans introduced heavy metals such as cadmium, arsenic and mercury to our soils through mining, smelting, industry, agriculture and the burning fossil fuels. So if you live near a current or former mine, smelter or industrial site, it may make sense to test the soil. Likewise, areas that are near or were previously home to agricultural activity - be it an animal or growing farm are likewise potentially tainted by that legacy. Finally, proximity to busy or high-traffic roads may be another sign of potential contamination.


Our disposal of materials containing heavy metals, a list that includes paint, electronics and sewage also contributes to the contamination. 


IS IT OK TO GROW FRUIT AND VEG IN MY GARDEN IF A DOG, CAT OR WILD ANIMAL HAS BEEN GOING IN IT?

Animal faeces in garden soil is something that is potentially dangerous, containing pathogens including salmonella and E. coli and potentially worm eggs. Some of these can survive for extended periods stretching to years but it is difficult to say precisely how long they exist in soil. 


According to a circular produced by Colorado State university on preventing the spread of E. coli from the garden to people, “Salmonella, E. coli, Campylobacter jejuni, Vibrio cholerae, parasites and viruses can contaminate produce through raw or improperly composted manure, irrigation water containing untreated sewage or manure, and contaminated wash water. Contact with mammals, reptiles, fowl, insects and unpasteurized animal products are other sources of contamination.”


More can be read here.

One alternative is to use raised beds. Another is to test the soil.


If you’re in doubt, you can run a Microbiology Examination of your growing space. This will check for the following:

  • Enumeration of E.coli

  • Enumeration of anaerobic sulphite reducing Clostridia

  • Enumeration of Enterococci

  • Enumeration of Salmonella sp

 

Safe Soil UK, a Terra Purus Ltd company

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