An important tool for keeping drinking water clean may be more risky than we think. New research finds a link between water chlorination and an increased risk of certain cancers.
Scientists at the Karolinska Institute in Sweden led the study, a review of past research and cancer research. They found evidence that people exposed to the highest levels of chlorine byproducts were more likely to develop bladder and colorectal cancer than those exposed to the lowest levels. The researchers say the relevant risk begins with a security threshold below the U.S. and Europe, indicating that current guidelines are not sufficient to protect the public.
Since the early 20th century, chlorine has been commonly used to disinfect drinking and recreational water. It helps eradicate or reduce the spread of dangerous diseases such as typhoid fever and cholera. But chlorine and other disinfectants are well known to have disadvantages. A major disadvantage is the formation of disinfectant by-products produced by mixing these chemicals with organic compounds in raw water, the most prominent by-product of chlorine called tribrain methane (THMS). Past studies have shown that THM may cause cancer in rodents, at least in rodents, but studies studying whether THM in chlorinated water is related to cancer in humans are more mixed.
Earlier reviews of the data often found limited evidence of a link between THM and bladder and colorectal cancer. But these comments have been around for over a decade now, and updates on the topic have been released since then, more likely research. Therefore, Karolinska scientists are trying to perform a latest meta-analysis of the research.
They finally analyzed data from 29 papers, the latest published last year. Although most studies have studied bladder and colorectal cancers, a total of 14 types of cancers were evaluated. The researchers failed to find a significant link between THM exposure and any other cancers besides the two. But they found that the highest THM level (relative to the lowest) was 33% higher with a bladder cancer risk and a 15% higher with a colorectal cancer risk. Importantly, this increased risk starts at the THM level, initially at 4.1 billion (PPB) (PPB) – the 80 ppb regulatory limit in the U.S. and the 100 ppb limit in the EU.
“Abstract, in this systematic review and dose response meta-analysis, we found limited evidence that exposure to THM in drinking water increases bladder and colorectal cancer,” the researchers wrote in a paper published in January. The risk.” A view of environmental health.
Today, there are other technologies that can disinfect drinking water, such as UV treatment. Practices such as removing organic matter from water before treatment with chlorine may reduce THM levels. But the researchers fully acknowledge that the data collected so far is not enough to prove the causal relationship between chlorination and cancer. They have not told the public to drink tap water based on their findings. At the same time, they urgently called for more good research studies to study and identify possible risks.
“What we're seeing is shocking, we need more high-quality research,” lead researcher Emilie Helte told The Guardian.
