Harmful asbestos in serpentinite rock

Serpentinite, a dark greenish natural stone with characteristic spots and whitish bands, is mainly used as a decorative stone. Serpentinite is still used today for flooring, cladding and other decorative products. However, serpentinite can release harmful asbestos fibers under certain conditions. These dangers exist above all when serpentinite is worked or broken .

Use of serpentinite as a rock

For centuries, serpentinite has been used to make facades, handicrafts, jewelry and much more. These stones were also used in historical buildings. serpentine-containing rocks were also used in historical buildings for columns, ballustrades and decorative stone, for example. The earliest products made of serpentinite as everyday objects are already known from the 15th century. These include drinking vessels, plates, screw-top bottles and other containers.

In recent decades, serpentine stones have only rarely been used for artistic purposes such as monuments. Today, they are mainly used as a raw material for gravel and chippings or as a base material for terrazzo and artificial stone floors.


Serpentinite rock – characteristics and properties

Both the The terms“serpentine” and“serpentinite” are of Latin origin and are translated as snake or serpentine stone. The term is intended to refer to the spot-like markings that resemble snakeskin.

In everyday language, the term serpentine is often used for serpentinite. However, this also stands for any mineral of the serpentine group. Although the two terms are closely related, they do not refer to the same thing. Therefore, if the rock is meant, the term serpentinite should always be used.

The natural stone serpentinite is mostly dark green or sometimes yellow-brown to purple and is characteristically interspersed with calcite veins.

Serpentinite is a metamorphic rock that was formed by tectonic and metamorphic processes under very high temperatures and pressure from basic rocks in the earth’s mantle through deformation. The resultant arrangement of the rock particles gives serpentinites their patchy, veined or striped appearance. Serpentinites are not acid-resistant and are not resistant to weathering.

Larger deposits of serpentinite can be found in the Ore Mountains (Zöblitz) and in the Fichtel Mountains (Rehau) as well as in the Harz Mountains and the Black Forest. There are also other larger deposits for mining worldwide.


Serpentine asbestos in serpentinites

Serpentine asbestos can occur in serpentinites in varying proportions. Asbestos is naturally occurring in certain fibrous silicate minerals with a rod-likeor needle-like appearance, which unites them as a collective term.

The ultrabasic (consisting of less than 45% silica) serpentine rocks consist of serpentine asbestos such as antigorite, chrysotile (clinochrysotile, orthochrysotile, parachrysotile) such as white asbestos, brown asbestos or green asbestos, as well as amphibole asbestos (e. g. a. tremolite and anthophyllite). Other minor components (less than 5%) may consist of calcite, olivine, magnetite, garnet, augite, hornblende and mica minerals.


Harmful asbestos fibers in serpentinite

For a long time, asbestos with its versatile asbestos fibers has been used industrially as an inexpensive and readily available“miracle cure” and served as a suitable raw material for the production of thousands of products. Its special properties, such as its resistance to acids, heat and insulation, were used in a wide range of products.

Serpentinite, which can naturally contain asbestos , is used for floor tiles, cladding and other decorative products. Clinochrysotile (white asbestos) is the most commonly used type of asbestos for these materials.

The major health risk posed by asbestos and inhalation exposure to asbestos fibers over long periods of time is now well known. Released asbestos fibers can cause lung diseases such as asbestosis and cancer. The use of asbestos has been banned throughout Europe since 2005 (1993 in Germany).

Materials containing asbestos, such as serpentinite containing asbestos , are hazardous substances.


Processing of asbestos-containing serpentinite – TRSG517

When working with asbestos-containing serpentinite, asbestos fibers can be released and enter the air we breathe. It is therefore imperative that suitable protective measures are observed, particularly for work such as drilling, milling, engraving and grinding.

Employers are subject to obligations in this regard via the Technical Rules for Hazardous Substances. TRGS 517, Technical Rules for Hazardous Substances, defines the requirements for“activities involving mineral raw materials potentially containing asbestos and mixtures and products made from them“. The employer must comply with the requirements of the Hazardous Substances Ordinance (GefStoffV) in accordance with TRSG 517 or take adapted measures that also comply with these.

In particular, TRSG 517 Respiratory protection and protective clothing for working with asbestos-containing materials which must be selected according to the conditions of use.


Limit values for asbestos fiber concentrations – Use of suitable respiratory protective equipment

Accordingly, respiratory protective devices are already prescribed for asbestos fiber concentrations of 10,000 F/m³ to 100,000 F/m³. Depending on the duration and activity, FFP2 masks, half masks with P2 filters or Masks with a blower and particle filter TM1P provide suitable protection. For asbestos fiber concentrations of 100,000 F/m³ to 300,000 F/m³ , masks with particle filter P3 should be worn. For over 300,000 F/m³ asbestos fiber concentrationsmasks with a blower and TM3P particle filter must be used. In general, after working with materials containing asbestos, the contaminated disposable protective suits must be disposed of or the reusable suits cleaned.

Recommendations on which personal protective equipment and conditions at the workplace for working with serpentinite containing asbestos can be found at in the brochure published by Suva (accident insurance in Switzerland): “Serpentinite containing asbestos: vital rules for working with it”. It describes numerous different types of work with serpentinite rock, from drilling to milling and grinding serpentinite containing asbestos, as well as important protective measures.


Asbestos measurement with GSA measuring devices SG12

In order to determine possible asbestos exposure due to the release of asbestos fibers, e.g. at the workplace, fibre measurements must be carried out in accordance with VDI 3492 for the measurement of asbestos fibers using suitable measuring devices.

With the GSA measuring devices SG12 it is possible to collect asbestos fibers over a certain time and defined air volume with a fine filter. After sampling with the SG12 the asbestos fibers can be precisely determined.

Through our partner company GSA Gesellschaft für Schadstoffanalytik mbH precise asbestos fiber analyses can be carried out under SEM (Scanning electron microscopy) using the latest equipment technology. Only after the results have been obtained can conclusions be drawn as to whether sampled (interior) areas are possibly contaminated with asbestos so that further necessary measures can be taken.

The GSA measuring devices SG12 can be used stationary. It is not only suitable for measuring even low concentrations of asbestos fibers, but also for sampling other inorganic fibrous particles in accordance with VDI 3492 and ISO 14966 such as KMF. A sampling period of eight hours is sufficient according to VDI 3492. According to DGUV 213-546, a measurement can be taken at the workplace within two hours. The measuring device can also be used to measure the various dust fractions such as A-dust or E-dust.


Asbestos in serpentinite rock: answers to five frequently asked questions

1. How do you recognize whether a rock contains serpentinite asbestos?

  • The identification of asbestos in serpentinite requires special tests. A visual indication can be a fibrous structure in the rock, but a precise analysis is necessary.

2. Which specific processing methods can release asbestos fibers from serpentinite?

  • Cutting, drilling or grinding serpentinite can release asbestos fibers. It is important to take protective measures to minimize exposure.

3. Are there protective measures that people can take when working with or coming into contact with serpentinite?

  • When handling serpentinite, protective measures such as wearing respirators, safety goggles and suitable work clothing should be taken.

4. What health effects can be caused by asbestos fibers from serpentinite?

  • Asbestos can lead to serious lung diseases such as asbestosis and lung cancer. Long-term exposure is dangerous.

5. Are there alternative materials that can be used instead of serpentinite to minimize the risk of asbestos exposure?

  • Yes, there are alternatives such as marble, granite or other non-asbestos stones that can be used for similar purposes.


Sources:

Image source: 123rf.com © vvoennyy , image no. 98664821

www.analyticalscience.wiley.com/content/article-do/asbest—eine-gesellschaftliche-und-analytische-bestandsaufnahme

www.de.wikipedia.org/wiki/Zöblitzer_Serpentin

www.geodienst.de/serpentinit.htm

www.baua.de/DE/Angebote/Rechtstexte-und-Technische-Regeln/Regelwerk/TRGS/TRGS-517.html

www.steine-und-minerale.de/atlas.php?f=3&l=S&name=Serpentinit

www.suva.ch/download/regeln-und-tipps/asbesthaltiger-serpentinit–lebenswichtige-regeln-fuer-die-bearbeitung/asbesthaltiger-serpentinit–lebenswichtige-regeln-fuer-die-bearbeitung

www.de.wikipedia.org/wiki/Asbest

www.de.wikipedia.org/wiki/Serpentinit