Is chlorine bleach

Hazards and risks from chlorine and sodium hypochlorite: No further measures to reduce the risk are required


Chlorine is produced in huge quantities and used as a disinfectant and bleaching agent for both household and industrial purposes. It is also widely used to disinfect drinking water and swimming pool water, and to remove bacteria and odors in the food industry. When chlorine gas is used to disinfect swimming pools and when treating drinking water, it is added to the water so that it is converted into sodium hypochlorite and hypochlorous acids in particular. All different forms are equally present, with the relative amounts varying with the acidity (pH) of the water. In connection with organic substances, they are broken down very quickly. Therefore, they are not bioaccumulating and do not remain in the environment.

According to the International Chemical Safety Program (IPCS), the biocidal properties of chlorine have somewhat offset public health concerns through the formation of the disinfection by-products, such as chloroform, in the chlorination process. As a result, alternative chemical disinfectants such as oxygen (O3), chlorine dioxide (ClO2) and monochloramine are increasingly used; it was found that each of them has been shown to form its own by-products.

What are the overall conclusions regarding the risk assessment for people exposed to chlorine and sodium hypochlorite?

The overall conclusion of the latest assessments is that there is no need for further information or testing and that there is no need for risk reduction measures; the measures currently in place to protect human health and the environment are sufficient.

The IPCS report1 insisted that the health risks from by-products in the amounts found in drinking water are extremely small compared to the health risks associated with inadequate disinfection. It is important that disinfection is not compromised by attempting to control these by-products. If local circumstances require a choice between microbiological limit values ​​or the limit values ​​of disinfectants and DBP, the microbiological quality must always take precedence. The report concluded that disinfection was efficient No way may be at risk.

How are we at risk from chlorine and sodium hypochlorite?

The main routes of exposure to chlorine and sodium hypochlorite (its solutions also called "Bleach" or "Bleach" are drinking water, food and contact with objects that have either been bleached or disinfected with them. People can also be exposed to chlorine in the workplace (in the production and use of chlorine as a chemical intermediate), e.g. B. the use of chlorine in water disinfection and indirectly through the environment.

By-products of disinfectants can be controlled by removing their organic precursor molecules and replacing or changing the disinfection practice. Natural organic material can be removed from the water before treatment, namely by means of spring water protection by means of coagulation, the use of activated carbon granulate, membrane filtering and ozone biofiltration as well as simple hygiene measures in swimming pools (such as showering before entering the pool and no urinating in the water) .

What are the potential human health effects of chlorine and sodium hypochlorite?

Above permissible exposure limits, human exposure to chlorine gas can lead to local effects on the upper respiratory tract due to the corrosive effects of chlorine, whereby such a risk is mainly associated with occupational exposure.

With regard to the exposure of humans and animals to chlorine in drinking water, the WHO report states that no particular adverse effects are known from the treatment.

Chlorine is not a problem with regard to mutagenicity and carcinogenicity and none of the chlorine by-products investigated to date is carcinogenic at the concentrations usually found in drinking water. In an exceptionally long toxicity study over 7 generations on rats, no difference could be found with regard to the occurrence of malignant tumors in animals that consumed drinking water with a chlorine content of 100 mg / l and in the control animals2.

However, bladder cancer is still debated even though the evidence of a link, despite its causal link, remains unexplained.

The Scientific Committee on Health and Environmental Risks (SCHER) of DG HEALTH (of the European Commission) supported the conclusion that there is currently no evidence of developmental reproductive toxicity from sodium hypochlorite based on the available database on hypochlorite and chlorine.

In the meantime it has been reported that under certain circumstances, especially in young children, asthma can be triggered by exposure to chlorinated water via the by-products of chloramines, even if scientific evidence does not clearly show that swimming in leisure pools increases the risk of childhood asthma.

Rash cases have also been linked to exposure to chlorine and hypochlorite, but none of these factors have been discussed in the most recent reference reports.

There were some links with rashes, although the evidence was not discussed in consensus reference documents.

2 CoC - UK Committee on Carcinogenicity of chemicals in food products for consumers and the environment. 2008 Annual Report - Second Declaration on Chlorinated Drinking Water and Cancer.

What is the guideline value for chlorine in the water?

The WHO guideline value for chlorine is 5 mg / l. It should be noted that this value was set cautiously. Interestingly, most people can taste chlorine and its by-products (e.g. chloramines) in concentrations below 5 mg / L and some even as low as 0.3 mg / L.

What risks do chlorine and sodium hypochlorite pose for the environment?

Sodium hypochlorite is very toxic to aquatic organisms. However, since the substance is extremely reactive, sodium hypochlorite that ends up in household wastewater reacts with organic substances and is disposed of before it even reaches the environment. Chlorine does not stay in the atmosphere either.

The EU tests for the risk assessment of chlorinated by-products on the entire effluent of chlorinated untreated wastewater showed that the halogenated by-products present neither increased the toxicity nor decreased the biodegradability of the wastewater. As this is a "realistic extreme" there should be no cause for concern about halogenated by-products generated by the use of chlorine in an aquatic environment. The same was inferred for the area of ​​our atmosphere.