In 2016 there were 13,648 cases of bladder cancer in Europe and of these, about 6,500 (5%) are attributable to trihalomethanes present in tap water. This is stated by a macro study that analyzes for the first time the levels of this pollutant in 26 countries of the European Union .

These compounds are generated after the process of disinfection of water with chemicals such as chlorine, which by reacting with organic matter, produce by-products such as trihalomethanes. "They are substances that have a certain toxicity," Cristina Villanueva, work coordinator and researcher at the Institute of Global Health of Barcelona (ISGlobal), a center promoted by "la Caixa" and is the body that has led this ambitious analysis.

According to several studies, long-term exposure increases the chances of developing bladder cancer , whether by ingestion, inhalation or dermal absorption. Its mutagenic and carcinogenic properties have been proven in animal experiments. For this reason, the limit allowed by the European regulation is 100 micrograms per liter.

None of the nationalities have reached such figures. "We comply with the law, water is potable and can be drunk," says Villanueva. But you should try to improve the levels of some cases or at least reduce it to the European average, which is 11.7 micrograms per liter. Above this value are several countries, including Spain (28.8) , Cyprus (66.2), Malta (49.4), Ireland (47.3), Hungary (26.3), United Kingdom ( 24.2) and Portugal (23.8).

Apart from analyzing the levels of trihalomethanes in European municipal water, the objective of the research also included estimating the burden of attributable bladder cancer. In total, as stated in the article just published by the journal 'Environmental Health Perspectives', 6,561 of these tumors are attributable to exposure to this pollutant in the European Union, representing 5% of annual cases (13,648 ).

Spain and the United Kingdom showed the highest estimated number of attributable cases, with 1,482 and 1,356, respectively. In other countries with high levels of trihalomethanes, the associated tumors are smaller, as in Cyprus, with 38. "This is explained by the high population of the previous countries and their high incidence in bladder cancer," explains the study coordinator.

"In the last 20 years, significant efforts have been made to reduce levels of trihalomethanes in various countries of the European Union, including Spain. However, current levels in certain countries could still lead to a considerable burden of bladder cancer that it could be avoided by optimizing water treatment , disinfection and distribution practices, among other possible measures, "argues Manolis Kogevinas, another of the ISGlobal researchers.

Based on the results of the work, the scientific team recommends that the main efforts to reduce the values ​​of this pollutant be directed to countries with higher levels. The study predicts that if the 13 countries with the highest exposure reduced their values ​​to the European average (11.7 micrograms per liter), the attributable cases would decrease by 44%, with 2,868 fewer tumors per year. Without a doubt, the effort would be worth it.

To carry out this work, the authors contacted different institutions and organizations responsible for measuring water quality in the countries analyzed, so that data on the concentration of total and individual trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane and bromoform) could be collected. . The values ​​of Spain were obtained from the 2013 report of the National Information System of Water for Consumption . "The biggest challenge has been the collection of representative data at the national level in all EU countries," says the coordinator, who encourages improving "the availability of this data, which should be easily and quickly accessible."

According to the criteria of The Trust Project

Know more

  • Science and Health

Interview "The next personalized medicine will take into account gender"

Health Increases myopia in children under eight years of age due to daily cell phone use

Health A blank night is associated with an increased risk of Alzheimer's