New substances added to US carcinogen report

Chronic bacterial infection, a flame retardant and some by-products of water treatment processes have been added to a list of identified carcinogens in the United States

Eight entries have been added to the US Carcinogens Report, a cumulative report commissioned by the US Congress to list substances known or likely to cause cancer in humans.

In the 15th Carcinogens Report 2021, the new entries added bring the total list to 256 substances, according to a December 23 press release.

The report is prepared by the United States National Toxicology Program for the Secretary of the United States Department of Health and Human Services. This year’s report coincides with the 50th anniversary of the 1971 United States National Cancer Act, promulgated by then President Richard Nixon.

The report identifies environmental factors, chemicals, infectious agents, physical agents – such as x-rays – and exposure scenarios, but does not include cancer risk estimates due to the many variables that may or may not affect the development of cancer.

In the latest report, chronic infection with the bacteria known as Helicobacter pylori, or H. pylori, was listed as a human carcinogen.

H. pylori is a spiraling bacterium that can enter the body through food, water, or utensils, lives in the digestive tract, and is the cause of most stomach ulcers. It is believed to enter the lining of the stomach to establish infection and can lead to stomach cancer. It is more common in countries with less established infrastructure around drinking water and sewage systems, but person-to-person spread is possible through saliva or other bodily fluids.

Another new entry in the report is the flame retardant chemical called antimony trioxide, which in Canada is used for household items such as mattress covers, furniture and rugs.

It is also used in the manufacture of polyethylene terephthalate, or PET, plastic. Antimony trioxide is both manufactured and important in Canada, according to the Health Canada website.

Health Canada states that Canadians are “likely to be exposed to low levels of antimony trioxide from environmental media (soil, drinking water, ambient air) from food and from contact with household items.”

The agency said it had conducted a screening assessment and “concluded that antimony trioxide is not harmful to the health of the general population at current exposure levels.”

The final entries in the latest report include six haloacetic acids (HAAs), found as byproducts of water disinfection, which are listed as reasonably likely to be carcinogenic to humans.

They are:

  • Bromochloroacetic acid (BCA)

  • Bromodichloroacetic acid (BDCA)

  • Chlorodibromoacetic acid (CDBA)

  • Dibromoacetic acid (DBA)

  • Dichloroacetic acid (DCA)

  • Tribromoacetic acid (TBA)

AHAs are formed during the water treatment process, when chlorine-based disinfectants react with organic matter in source water.

Health Canada States that the maximum acceptable concentration for total HAAs in drinking water is 0.08 milligrams per liter, based on a local moving annual average of a minimum of quarterly samples taken from distribution systems.

“Cancer affects the lives of almost everyone, directly or indirectly,” Rick Woychik, director of the US National Institute of Environmental Health Sciences and NTP, said in the release. “As the identification of carcinogens is a key step in cancer prevention, the publication of the report represents an important government activity aimed at improving public health. “

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