Results show
total levels of each of the 32 Metals, Heavy Metals, Metalloids and Minerals in your soil sample and are presented as milligrams of the element per kilogram air dried soil (mg/kg). Soil samples are analysed by our Laboratory here in Australia via Total Acid (Aqua Regia) digest using - Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) | Elements tested include -
Antimony (Sb), Silver (Ag), Arsenic (As), Lead (Pb), Cadmium (Cd), Chromium (Cr), Copper (Cu), Manganese (Mn), Nickel (Ni), Selenium (Se), Zinc (Zn), Mercury (Hg), Iron (Fe), Aluminium (Al), Lithium (Li), Beryllium (Be), Boron (B), Vanadium (V), Cobalt (Co), Strontium (Sr), Molybdenum (Mo), Barium (Ba), Thallium (TL), Bismuth (Bi), Thorium (Th), Uranium (U), Calcium (Ca), Magnesium (Mg), Potassium (K), Sodium (Na), Sulphur (S), Phosphorus (P)
The primary purpose of having a soil test is to
safeguard human and animal health. In a
world first, we present results that both prioritise human friendly visual design and the use of recent Australian data that emphasises background levels of metals and elements as they have
occurred in nature since humans have walked the earth. A secondary, but equally important reason is to prioritise
plant growth and health via the assessment of
Soil Nutrient availability and Soil Fertility & Health, which of course leads to optimal human and animal growth & health.
The presentation of the soil analysis results also considers...
Potential
soil contamination from man-made sources, especially from the heavy metals of most concern to human health (Lead, Cadmium, Arsenic and Mercury)
Heightened local natural geological background levels
How results compare to
Australian Guidelines for Health Investigation Levels (HILs) for Soil Contaminants
Potential problems and dangers for insects, soil microbiome, worms and of course
plants. Note that our
Soil Nutrient availability & Fertility Analysis provides a more in-depth focus on
optimal plant growth & health. This test investigates soluble, exchangeable or available levels of soil elements and takes into account many variable soil parametres like pH, soil type,
available/exchangeable plant nutrients and much more and is offered as an add-on to this 32 Element Core Soil Analysis.
Additional
exposure and health information is available in the
blue links within each Metal/Mineral result.
Relevant, interesting and timely information is also provided uniquely within each Metal/Mineral result.
Results need to meaningfully gauge the extent of any potential man-made contamination or indeed, greater than average local natural background geochemical levels of an element. This then reveals any heightened human, animal and plant exposure to toxic heavy metals. To achieve this, results are presented in a way that simply and visually shows the degree to which each individual element result is higher than a Precautionary Threshold Value (PTV) in addition to an Upper Threshold Value (UTV).
These Threshold Values are based on extensive and careful assessment of current and historic research, both locally and globally. In determining the PTV and the UTV for each element tested, we carefully considered the fine line between being too relaxed and too alarmist, particularly with regard to potential exposures to the highly toxic heavy metals.
The estimation of these
Australian relevant Threshold Values is possible because of data publically available from the mammoth project conducted by the
National Geochemical Survey of Australia (NGSA): The Geochemical Atlas of Australia in 2011, that shows national geochemical background averages and percentiles for 59 metals and minerals at several soil depths over most of the Australian continent. Similar datasets are available separately for Europe and the USA. In 2017 the work of
Clemens Reimann and Patrice de Caritat helped us clarify our
Precautionary Threshold Value and
Upper Threshold Values for each element we test in the soil sample.
Importantly, each element/heavy metal result has Unique Visual cues (Length and Colour of the result bar) and Text-based Information (Numeric results, Australian based PTV and UTV values, Australian Guidelines for Health Investigation Levels for Soil Contaminants, called HILs and other global background values for comparison). This multifaceted approach to result presentation helps highlight potential dangerous exposures (for humans, animals and food grown in the soil) and in making decisions whether too do nothing or to investigate further. This in turn helps to demarcate potential ongoing or historic man-made contamination from above average natural geological element levels.
Our Precautionary Threshold Value (PTV) is calculated from the Australian NGSA geochemical background averages (Medians) for each element with an adjustment (Median + 2 x Median Absolute Deviation) that is more robust against the effect of data outliers. The PTV however is a conservative and environmentally friendly (low) threshold value, that can, on occasion, produce an overly cautious response suggesting that further investigation or even soil decontamination is needed. To provide balance, reduce alarm and encourage further local investigations, the Upper Threshold Value (UTV) is less sensitive and enables you to see if your soil sample result is higher than 98% of all background soil samples collected in Australia as part of the NGSA for that element.
Each individual element result contains bars that dynamically change length and colour dependant on the analysis value. The longer the bar, the greater the result is above above the PTV. The bar also changes colour from beige to red when your result is greater than the UTV. This is a trigger for potential man-made contamination, particularly for the heavy metals like Arsenic, Cadmium, Lead, Mercury, Antimony, Aluminium, Chromium, Thorium, Uranium and even Manganese, Zinc and Nickel. However, it is also important to note that natural local geological levels can vary, even within a few kilometres. Bottom line - if result bar turns red, further investigation is strongly indicated. Of benefit is simply asking neighbours and councils if natural geological levels of specific metals (high in your result) are elevated in your area or if industry, agriculture or mining has been or currently is present.
Some of us prefer to have another human explain things. If that's you, then we provide a
consultation over the phone/online directly with Toxtest owner, Hartmut Gunther. Cost is $35 for 15 mins or increments thereof.
Contact Hartmut Günther to request a consult or ask a question.
Finally, the
National Environment Protection (Assessment of Site Contamination) Measure 1999 (updated May 2013) provides Australian Guidelines for Health Investigation Levels for Soil Contaminants, called HILs, of Heavy metals and other toxic chemicals. We include these within the results when they are available. Of relevance here is the
overview of how all the HILs are derived but more specifically
how the HILs for the heavy metals are derived. A graphic summary of these values is after
references. While the Government HILs take into account human health in relation to toxic exposures, they are created primarily as guidance to industry, business, councils and developers. Additionally, the HILs don't fully take into account multiple chemical exposures by an individual at one time (this is a new and emerging field of toxicological investigation), individual genetic differences, long-term accumulation in the body of heavy metals and the case where people may be eating more than 10% of produce grown in the soil.
