What Studies Are There That Detail the Effects of Chlorine on the Human Body?

¿Qué Estudios Existen que Detallan los Efectos del Cloro en el Cuerpo Humano?

Chlorine is an unstable gas that reacts quickly on contact with other substances, forming chemical byproducts that can be toxic and irritating. However, its use has been greatly extended over time as a disinfectant and cleaning product, even in local and national water networks. For this reason, on this occasion we will talk about chlorine in the human body and the different studies that have been carried out with the aim of determining the risks that this can represent for people.

Studies on chlorine in the human body and the consequences of exposure to it

Over time, different studies of chlorine in the human body have been carried out, due to its widespread use as a cleaning and disinfection product for water networks in cities. Below, we will mention some of them and the effects that have been found from frequent exposure to this product, both ingestion and in other uses such as showering or swimming pools.

Problems associated with pregnancy and births

The first study we want to cite was carried out by Chun-Yuh Yang and relates the chlorination of drinking water to adverse birth outcomes in Taiwan, considering that chlorination is the main water disinfection strategy in that territory. Thus, the use of chlorinated water has been hypothesized to lead to various adverse birth outcomes, including preterm delivery and low birth weight.

The same specialist has also analyzed the use of chlorinated water and its relationship with adverse deliveries, taking both municipalities with chlorinated water treatment and others without chlorine. While the study has been unable to show a link between chlorine and low birth weight in infants, it has been linked to the risk of preterm birth.

On the other hand, studies have been carried out linking the Norwegian waterworks register with data from 1994 on the practice of chlorination and the Medical Register of Births from 1993 and 1995. Calculating the proportion of the population exposed to chlorination, this study found that 1.8% of births had birth defects ; A risk of 1.14% for malformations, 1.26% for neural tube defects and 1.99% for urinary tract defects has been extracted from this.

Bladder cancer

On the other hand, it is necessary to refer to the studies of chlorine in the human body and its relationship with bladder cancer. The study to which we refer mainly took consumers of chlorinated drinking water. What was done was to obtain the residential histories through interviews of 614 deaths from bladder cancer and 1074 deaths from other causes. The data includes communities whose surface water has been disinfected with chlorine and a combination of chlorine and ammonia since 1938.

In this sense, the mortality rate from bladder cancer among people residing in communities supplied with chlorinated drinking water, in relation to people with access to chloramine-disinfected drinking water, was 1.6% using all controls. When the group was restricted to people who died of lymphoma, the probability of mortality rose to 2.7%.

In conjunction with this study, WD Rey and LD Marrett also looked at controls for bladder cancer and chlorination byproducts in treated water. To do this, they were based on the population of Ontario, Canada. The results obtained show that people exposed to an estimated level of THM > or = 50 micrograms/liter for 35 years or more had a 1.63% higher risk than those exposed for less than 10 years. Thus, it was shown that the risk of bladder cancer not only increases with the duration but also with the concentration of exposure to chlorination byproducts.

male reproduction

Over time, epidemiological interest in the role of chlorine byproducts in adverse reproductive outcomes of masculinities has grown. What has been analyzed in these studies is whether DBPs (drinking water disinfection by-products) can alter male reproductive parameters, including epididymal and testicular histology, as well as sperm number and motility. Abnormalities in sperm motility seemed, in these studies, to predict more general toxicity in the male reproductive system.

Observing the results, it has been seen that an exposure of 22 to 39 mg/kg of BDCM, as well as 55 and 188 mg/kg of CH have not produced systemic toxicity. However, exposure to 39 mg/kg BDCM significantly reduced mean straight line velocity, trajectory, and also curvilinear velocity of retrieved sperm, with lower average modal velocity.

The study maintains that:

“Exposure to 188 mg/kg CH significantly decreased both the percentage of motile and progressively motile sperm. This CH exposure shifted the straight-line velocity distribution to a lower modal velocity range. These are the first reproductive toxicity data from exposure to BDCM and CH. The observed effects on sperm movement occurred in the absence of carcinogenesis.

Risk of asthma and airway problems

Another problem that has been studied in relation to water chlorination has to do with its relationship with the risk of asthma in childhood. Thus, a study by Alfredo Bernardo, Silvia Carbonelle, Clara de Burbure, Olivier Michel, and Marc Nickmilder explored the relationships between childhood asthma, atopy, and cumulative attendance at the pool (CPA), taking as cases 341 children between 10 and 13 years of age.

What was observed in this case was an elevated risk of eNO that was increased by CPA. However, the likelihood of developing asthma was increased with CPA only in children with serum IgE. Effects, in all cases, related to the dose of chlorine and attendance at the pool before 6 and 7 years of age. It was then shown that the use of chlorinated swimming pools in young children interacts with the atopic state, promoting the development of childhood asthma.

Hand in hand with the above, other studies have focused on the health of professional swimmers in chlorinated pools. Studying their diseases, a strong prevalence of rhinitis, atopy, asthma and hyperreactivity of the respiratory tract, including the induction of lower and upper respiratory symptoms, has been seen. These problems were observed both in children who go to swimming pools and in high-level swimmers and in lifeguards who also maintain permanent contact with chlorinated water.

allergic diseases

Populations in regular contact with chlorination products have long been shown to be at increased risk of allergic diseases and common allergy-associated respiratory disorders. Other studies have focused on this part, collecting experimental evidence that suggests that chlorination products promote allergic sensitization, compromising the permeability or immunoregulatory function of epithelial barriers.

The findings that have been made in this regard led to the hypothesis that chlorine increases allergic diseases. In this sense, it is stated that the prevalence of these diseases can be linked less to exposure to microbial agents and more to excessive exposure to chlorination products, which is the currently most implemented method to achieve water hygiene.

Along with allergic diseases, an increased risk of eye irritation and discomfort has also been seen in cases of people who are frequently exposed to chlorinated water. Studies in this regard have linked irritation and eye strain with the use of chlorinated pools. However, it can also be deduced from this the affectation in this sense that the frequent use of chlorinated water in daily life, including shower water, can have.


Taking into account the previously mentioned studies of chlorine in the human body, one of the best ways to prevent the risks of chlorine exposure in the domestic network is with the use of filters. Shower filters can neutralize the impact of chlorine on the human body, favoring the health and well-being of the inhabitants of the houses.

For this reason, if you are looking for a quality filter to implement in your shower and thus mitigate all the effects that chlorine and other water pollutants have on the human body, at Sanaté we have the best option for you . We have shower filters designed for your well-being and that of your family during each shower. Contact us! and buy professional filters that do guarantee healthier and cleaner water.

Back to blog