Measurement of radioactivity in samples

Radon is an odourless and invisible radioactive gas that can be present in indoor air. Long-term exposure to high radon levels considerably increases the risk of lung cancer. Radon is undetectable by the human senses, so the only way to determine the concentration of radon in indoor air is to measure it.
 
Radon concentration in indoor air must be determined by a reliable measurement method. Radon levels in indoor air should be measured at least every 10 years. Radon measurement can be ordered from either STUK or another operator that uses a method of measurement approved by STUK.

Read more about indoor air alpha radon detector measurements

In underground mines, excavation sites and tunnels, the radon concentration is often measured with short-term air samples taken from the workplace, because it is often not possible to carry out an alpha track radon measurement lasting at least two months in underground mines and excavation sites, which is normally required for workplaces. The measurement is made with a Pylon Model AB-5 meter and the measurement result is reported to the supervising authority in accordance with the general delivery conditions.

Where are measurements to be done?

Measurements are to be done in underground mines, excavation sites and tunnels:

• at the excavation site, where the mining work is in progress
• in service and break rooms, that are being used
• in other underground workplaces, that are constantly in use

Radon measurements are also carried out during the construction and finishing works after the excavation process.

Ordering

Fill out the order form for radon measurement in mines and quarries and send it to the e-mail addresses indicated in the form. After receiving the order, the recipient of the order agrees with the customer on the time when the measurement will be performed. At the end of the measurement, a test report will be sent electronically to the e-mail address provided by the customer. The customer is invoiced for working time, travel expenses, per diems and any overnight expenses.

Ordering form, in Finnish only (pdf) 

Additional information

Radon in underground mines, excavation sites and tunnels 

As a rule, swipe samples are collected to ensure the leak-tightness of sealed sources.  
If necessary, swipe samples can also be taken from other locations.

Gamma spectrometric determination: Co-60, Cs-137, Ir-192, Am-241 and others
Alpha and beta radiation sources: Sr-90 and others

Order a measurement here: order form (pdf)

Construction products and materials
 
Radioactivity of construction products and materials is measured by gamma spectrometry. The measurement determines the values for construction products and materials in accordance with STUK Regulation S/6/2022, Sections 6 and 13. The measurement meets the requirements for measurement accuracy and measurement system set out in STUK regulation S/7/2021.
 
Construction products and materials may include, for example, raw materials for concrete or construction products, concrete products or other construction products of mineral origin, or gravel, crushed rock or ash used in earthworks.
 
Construction products are covered by the Construction Products Regulation (EU) No 305/2011.
 
Analysis of an ash sample
 
As a rule, ash samples are always subjected to an extensive analysis, i.e. an advanced gamma analysis. This is necessary when ash is treated as waste, utilised in fertilisers or used for any purpose other than as a building material. A more extensive investigation is also needed, for example, for an investigation of natural radiation exposure in accordance with the Radiation Act (section 146) or for determining whether the processing of ash waste requires STUK's approval (section 84 of the Radiation Act). The extensive study measures the activity concentrations of the natural decay series of uranium-238 and thorium-232 and also the values for construction products.
 
If the ash is used only in a construction product (for example, in the construction of houses, streets, roads and courtyards or in other earthworks), it is sufficient to measure the ash as a construction product, meaning that only the construction product values are measured. If you are not sure about the scope of the analysis, it is advisable to do an extensive analysis of the ashes, i.e. an advanced gamma analysis. If you only want to order a measurement for the ash as a construction product, select the item “Ash as a construction product only” from the form. Otherwise, STUK always performs an extensive analysis on the ashes, i.e. an advanced gamma analysis.
 
If you are not sure whether you should choose an advanced analysis for your ash sample, please contact us by email for advice. Send the email to [email protected].
 
Radiation Act 859/2018 (translated from Finlex.fi) (pdf)
Radiation and Nuclear Safety Authority Regulation on Practices that Cause Exposure to Natural Radiation S/6/2022 (Stuklex.fi)

Measurement of radioactivity of construction products or ash (pdf) (in Finnish)
 
You can fill in the forms online. If you cannot fill in the form in a browser, first save the form to the workstation and then complete it.

The NORM (Naturally Occurring Radioactive Material) analysis packages analyse the activity concentration of naturally occurring radioactive substances. The analysis is suitable for  
industrial sectors that use natural materials in their operations and that are obligated to determine radiation exposure in accordance with the Radiation Act (section 146 of the Radiation Act). For waste, the analysis will determine whether the waste treatment requires STUK's approval (Section 84 of the Radiation Act).  
 
Some examples of sample origins are mining and underground excavation, metal production, groundwater treatment plants, production of phosphoric acid or fertilisers or energy generation processes. The analyses may be carried out on solid, liquid or air samples.  
 
Sample materials can be, for example:

• industrial raw materials, by-products and end products
• process precipitates 
• air filters
• effluent waters
• process waste. 

Analyses on the ash from power plants can be ordered using the form for measuring the radioactivity of construction products and ash, which is on the page Construction products and ash.
 
For more information on the regulatory requirements for monitoring of natural radiation, please contact [email protected].

Also see:
Radiation Act 859/2018 in Finnish (Finlex.fi)
STUK Regulation S/6/2022(Stuklex.fi)
 
NORM analysis packages and ordering instructions:

• Form for the measurement of radioactivity in industrial materials or industrial waste (NORM) (.pdf)
• Sample collecting instructions – Industrial materials and industrial waste (NORM) (.pdf)

For more information about sample collection or the analyses, please contact 
[email protected]
 

Activity concentrations of radioactive substances can be determined from food and environmental samples.  
 
Radioactive substances emitting gamma radiation, such as cesium-137, are determined from food and environmental samples by gamma spectrometry.  
 
Moreover, foodstuffs and environmental samples can be subjected to a radiochemical analysis to determine the activity concentrations of strontium (Sr-90), plutonium (Pu-238, Pu-239,240), americium (Am-241) and the naturally occurring radioactive substances, such as uranium (U-234, U-238), polonium (Po-210) and lead (Pb-210).  
 
Foodstuffs

• such as mushrooms, berries, fish, game and grain
• processed foods such as chocolates, biscuits, spices and juices. 

Gamma spectrometric determination: caesium (Cs-137), etc.
Radiochemical determination: strontium (Sr-90), americium (Am-241), uranium (U-234, U-238), polonium (Po-210) and lead (Pb-210), total alpha and total beta activity
ICP-MS determination: uranium
 
Environmental samples

• sediment samples, soil samples
• lichens, mosses, tree leaves and needles
• river, lake, sea and rain water.

Gamma spectrometric determination: cobalt (Co-60), caesium (Cs-137), etc.
Radiochemical determination: strontium (Sr-90), americium (Am-241), plutonium (Pu-238, Pu-239,240), tritium (H-3), uranium (U-234, U-238), polonium (Po-210) and lead (Pb-210), total alpha and total beta activity, radon (Rn-222 from water samples)
ICP-MS determination: uranium

Form for a measurement of foodstuffs and environmental samples (pdf)  (in Finnish)

Measurement of radioactivity in private wells  
 
The sum of the activity concentrations (total alpha) of radon (Rn-222) and long-lived alpha emitters can be measured from well water samples sent by private individuals. The total alpha measurement reveals whether, in addition to radon, the water contains significant quantities of other naturally occurring radioactive substances, such as uranium, radium and polonium. Uranium and thorium can also be determined separately by the ICP-MS method.
 
When water is used, radon is released into indoor air. If the radon concentration of the water is 1000 becquerels per litre, using the water will increase the radon concentration in indoor air by an average of 40 becquerels per cubic metre (Bq/m³). This estimate is highly variable due to the different ventilation technologies used in buildings and the amount of water used, among other things. If the radon concentration in indoor air has not been measured before, you should measure it.
 
With regard to private wells, the Ministry of Social Affairs and Health has issued a decree on small units (401/2001), which lays down a quality recommendation of 1000 becquerels or radon per litre of water from wells used for private purposes.
 
Measurement of radioactivity in water supplied by waterworks
 
Water samples from waterworks, water supplies and other public spaces are measured to determine the activity concentration of radon, long-lived alpha radiation emitters and, if necessary, long-lived beta radiation emitters. If these measurements indicate that the indicative dose caused by the water might exceed 0.1 mSv, the radioactivity of the water can be measured in more detail. The more detailed measurements include, for example, the concentration of polonium (Po-210), lead (Pb-210) or radium (Ra-226, Ra-228) concentration. These are measurements in accordance with the Drinking Water Directive. The results are used to calculate an indicative dose caused by the water.
 
In addition to private laboratories, the activity concentration of radon in household water can be determined at STUK. All determinations of radioactivity in household water can be ordered from STUK's laboratory.
 
Instructions for collecting the sample (pdf). Only in Finnish. Soon to be published also in English.
 
Enclose the order form with the water sample.
 
Order forms:

• Order form for private customers (in Finnish)
• Order form for waterworks (in Finnish)

Results
 
When the activity concentration of radon and the total concentration of long-lived alpha-active substances are determined from a water sample, the measurement result will be delivered to the customer within approximately two months of the time the sample arrived at STUK.
 
If solely radon is measured, the result is sent out within approximately two weeks.
 
Further information can be read in FInnish or Swedish on the website of National Authority for Welfare and Health (Valvira). ​​

Direct and indirect methods for the determination of radioactivity in the body

The amount of substances emitting gamma radiation can be measured directly from the human body or from a single organ, such as the thyroid gland. The direct measurement takes about half an hour. Before the measurement, the person to be measured takes a shower and puts on a measuring suit.  
 
Secretion samples (including urine) can be used for indirect determination of the activity concentrations of tritium (H-3), polonium (Po-210), uranium (U-234, U-238) and lead (Pb-210). All these determinations are carried out radiochemically by separating the test substance from the sample.  
 
The measurement results serve as the basis for estimating the radiation dose caused by radioactivity. In a simple case, the dose can be estimated on the basis of a single measurement, but if the case is more complex, the dose assessment requires several measurements scheduled for a specific time period.
 
The people measured are radiation workers or representatives of population groups defined in the monitoring programmes. The workers' measurements are carried out as service measurements in accordance with the agreed programme or when there is reason to suspect that the worker’s body has become internally contaminated with radioactive substances.  
 
Private persons usually have no reason to seek radiation measurements of the body. However, the measurement may be performed if deemed necessary on the basis of a joint assessment with another authority.
 
The measurements are performed as monitoring and service measurements and charged according to STUK's service price list in force.

In addition to construction products, food samples, environmental samples and household water, STUK measures radioactivity from various many other types of samples according to customers' needs. The measurement method is either gamma spectrometry or radiochemistry.
 
Examples of sample types are electronic components, calibration solutions, clothing contaminated with radioactive substances, grinding wheels or other similar small items.

Gamma spectrometry measurements in a laboratory
 
Gamma spectrometry can be used to determine the radioactivity of almost any sample. The sample itself rarely places restrictions on the measurement as long as the sample fits the detector. In gamma spectrometry, the sample does not need to be digested, but can often be measured as is.
 
Gamma spectrometry identifies gamma-emitting radionuclides from the sample. In certain cases, the activity concentration of the radionuclide may also be determined or estimated.
 
Radiochemical laboratory analyses
 
A radiochemical assay almost always requires a separation of the element from other interfering substances. A radiochemical assay can be carried out on any sample that can be converted into a solution. The elements that can be determined by a radiochemical assay are carbon-14, tritium, strontium, uranium, lead, polonium, plutonium and americium. Without an element separation process, it is possible to determine the total alpha concentration of the sample (the total quantity of substances emitting alpha radiation) and radon.

Order

• Form for other radioactivity measurements (pdf). Only in Finnish. Soon to be published also in English.