The new study by the Klade technical office on biocides in evaporative cooling systems shows a need for action.

A study commissioned by the Vienna Environmental Ombudsman’s Office and recently published deals with the use of biocides in cooling systems: Open evaporative cooling systems in particular are often colonized by dangerous biofilms, which can also contain Legionella or Pseudomonas bacteria. Due to the permanent contact of the cooling water with the ambient air, these can sometimes travel for kilometers and lead to severe or even fatal lung infections if inhaled by local residents. Such cases have been documented in numerous studies and were also documented by AGES in Vienna in 2007. The study provides the following findings, among others:

• The use of biocides in evaporative cooling systems is a black box in Austria
• The locations of potentially dangerous cooling systems are largely unknown
• Germany can be seen as a role model as far as official regulation is concerned.
• The study compares active ingredients and systems

and recommends, in addition to the elimination of structural defects and the very regular chemical and technical maintenance of these systems, above all oxidizing processes with low AOX formation. These include the production of active chlorine by electrolysis from sodium chloride on site or the use of chlorine dioxide that is as pure as possible. Unfortunately, there are still few references in Austria for processes that use environmentally friendly hydrogen peroxide or that work with monochloramine or ozone. However, the example of the Vienna Twin Tower, where an ozonization system was installed, shows that under the right conditions, both the use of biocides relevant to wastewater and (usually environmentally harmful) corrosion inhibitors can be dispensed with. The system paid for itself in two to three years due to the large savings in (environmentally toxic) chemicals.

The use of the biocidal active ingredients CMIT/MIT, DBNPA and glutaraldehyde is largely discouraged in the study by the Klade technical office, not least for reasons of employee protection.

The use of the WIDES database was included as a MANDATORY criterion in the Austrian Ecolabel for schools.

The revised Guideline UZ 301 for schools and teacher training colleges was unanimously adopted by the Ecolabel Advisory Board at the end of June 2022.

The current version can be found at: https://www.umweltzeichen.at/schulen/richtlinie

It lists criteria for the use of disinfectants under point 4.9 (Chemical products and cleaning), which include:
If surface disinfection is necessary in accordance with hygiene regulations (HACCP), it is preferable to use products based on oxygen scavengers, alcohol or organic acids or products from the WIDES database that do not contain any substances marked in red.

Use fragrance-free alcohol-based products for hand disinfection, preferably products that are suitable for hand disinfection during pregnancy (see WIDES ratings – use filter at the bottom).

The AustrianAction Plan for Sustainable Public Procurement (naBe Action Plan for short)recommends the WIDES database to support the ecological procurement of disinfectants.

The Procura+ European Sustainable Procurement Network, initiated and coordinated by ICLEI, is an association of public bodies and regions in Europe for networking, exchange and the establishment of sustainable and innovative procurement. The Procura+ Award recognizes existing and successful examples of sustainable and innovative public procurement. In 2017, the WIDES disinfectant database was submitted for the Procura Plus Award and received an honorable mention(http://www.procuraplus.org/awards/awards-2017).

The program management of the Procura Plus Network – ICLEI in Freiburg – considered the WIDES database to be a remarkable strategy for sustainable and innovative procurement and asked the submitting authority, the Vienna Environmental Ombudsman’s Office, to prepare a case study.

This was drawn up with the involvement of Klade Technical Office and published on the Procura Plus website: http://www.procuraplus.org/case-studies

The case study can be here (English only)

On behalf of the Vienna Environmental Ombudsman’s Office, the Klade Technical Office took a closer look at the range of disinfectant household products. The study examined the range of all-purpose cleaners, cleaning cloths and sponges, gels, soaps and sprays as well as detergents and washing-up liquids found in supermarkets and drugstores for which the manufacturer explicitly claims a disinfecting effect.

This can be recognized by formulations such as “antibacterial”, “disinfectant”, “eliminates 99.99 % of bacteria” or “eliminates fungi, mould, algae or viruses”. An inventory in shopping centers revealed 78 such products. The packaging was evaluated with regard to the type and quantity of biocidal active substances used. Data sets published by the European Chemicals Agency ECHA were used to evaluate the active substances with regard to their effects on health and the environment^[1], ^[2].

The evaluation of the active substances examined can be summarized as follows:

• • The use of biocidal active substances such as organic acids, alcohols and peroxides generally appears to be unproblematic. However, caution is advised with regard to their irritating or corrosive effect on the skin and eyes. Splashes should be avoided during application and gloves should be worn. The environmental risks are rather low due to the generally rapid biodegradability.
  • The use of kitchen sponges and cloths containing silver appears to be problematic as highly environmentally toxic silver ions can be released. Silver does not decompose further and can accumulate in the sediment of natural waters. The use of low doses in the household promotes the development of resistant germs, which in turn can impair the sensible use of silver in the healthcare sector (e.g. for catheters and in wound dressings).
  • The use of sanitizer for laundry disinfection is particularly problematic. The biocidal active ingredients used – benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC) – are important representatives of the quaternary ammonium compounds (QAV) group. Due to their poor degradability, they are found in sewage sludge and sediments. In addition, long-term exposure of microbes to QAV in the environment also appears to increase their resistance to clinically relevant antibiotics. The frequent use of sanitizers can also lead to health problems: Since QAV are absorbed by the clothing fibers during washing, wearing the clothing can lead to indirect contamination of the living environment. For example, surprisingly high quantities of these active substances were found in the dust of school ventilation ducts. This is also a cause for concern because these chemicals also have a certain skin-sensitizing potential. These potential application risks are offset by low or questionable benefits: In general, disinfecting laundry only seems justified if it is already contaminated – for example due to an existing (fungal) infection – and cannot be washed at 60°C.

Hinsichtlich des potentiellen Nutzens einer Desinfektion im Lebensumfeld „Haushalt“ stimmt die die überwiegende Mehrheit der HygieneexpertInnen darin überein, dass eine unbegründete routinemäßige Desinfektion der Gesundheit eher schadet als nutzt. Nur in ganz spezifischen Situationen erscheinen desinfizierende Maßnahmen im Haushalt gerechtfertigt – etwa wenn ein Familienmitglied an einer hochansteckenden Krankheit leidet oder bei Personen mit stark geschwächtem Immunsystem, z. B. in Folge einer Chemotherapie oder aufgrund ihres Alters.

The study therefore suggests making private individuals’ access to disinfectants dependent on a justified need: One proposed measure involves shifting sales from supermarkets to pharmacies, in conjunction with appropriate specialist advice. A further proposed measure is aimed at implementing the EU Biocidal Products Regulation: in the course of product approval, applications in the household could be scrutinized by hygiene experts with regard to their benefits. As a result, the quantity or packaging size could be adapted to the requested application or the packaging could contain instructions for use.

The study can be here can be downloaded here.

A statement on this can also be found on the website of the Vienna Environmental Ombudsman’s Office: http://wua-wien.at/positionen-und-stellungnahmen/studie-desinfektionsreiniger-2

[1] https://echa.europa.eu/de/information-on-chemicals/registered-substances

[2] https://echa.europa.eu/de/information-on-chemicals/biocidal-active-substances