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Drinking water quality: Better biomarker of DBP exposure.

Spivey A - Environ. Health Perspect. (2009)

View Article: PubMed Central - PubMed

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When we drink chlorinated water or shower in it, we’re exposed to chemicals called disinfection by-products (DBPs), which form when organic matter in water reacts with chlorine and other treatment chemicals... Some human epidemiologic studies have found associations between exposure to high levels of DBPs and increased risk of problems such as cancer and reproductive effects... TCAA, on the other hand, persists in the body for several days, offering a longer window for measuring exposure, Zhang says... However, she adds, knowing only water levels of any DBP does not address how much water anyone consumes... In Zhang’s tightly controlled study, for 15 days researchers delivered 3 L of cold tap water that contained a known amount of TCAA to each of the 46 participants... The results showed that blood levels of TCAA made a better biomarker than urinary levels, but for large epidemiologic studies, measuring urine levels is more practical because the sample is collected less invasively, says Zhang, who often conducts field work... She concludes from her results that taking urine measures over two days and averaging them is preferable to a one-day sample, as the results showed better statistical reliability with repeated measures... Susan Richardson, a research chemist with the U.S. Environmental Protection Agency, says the study has many strengths, among them a large group of participants that provided more statistical power than previous studies of TCAA, careful control of TCAA ingestion, and strong correlation between TCAA levels in the ingested drinking water and levels in the participants’ urine and blood... Those elements add up to her opinion that TCAA is ready to be used as a biomarker of DBP exposure in epidemiologic studies... Clifford Weisel, a professor of environmental and occupational health at UMDNJ–Robert Wood Johnson Medical School, suggests the TCAA biomarker would be useful in a study when combined with some measure of other routes of DBP exposure, such as showering and bathing. “These studies show that TCAA will make a potentially good biomarker of ingestion of the haloacetic acids, in particular TCAA... TCAA isn’t a perfect biomarker... It’s not yet known whether it can indicate ingestion of the most dangerous DBPs—other classes of compounds, such as iodinated and brominated compounds, which have been found to be much more toxic than chloroacetic acids... Access to subjects and timing also are important aspects to consider... But overall, researchers call these findings a step in the right direction in an area that needs much more work. “These studies are very important because we have very few biomarkers for disinfection by-products,“ Nieuwenhuijsen says.

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Study participants were randomly divided into 5 groups. One group served as controls and received TCAA-free bottled water. The other groups received TCAA-free water mixed with one of four concentrations (12.5%, 25%, 50%, or 100%) of city tap water containing a known concentration of TCAA.Adapted from Zhang W, et al. J Water Health 7(3):359–371 (2009), with permission from the copyright holders, IWA Publishing.
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f1-ehp-117-a487: Study participants were randomly divided into 5 groups. One group served as controls and received TCAA-free bottled water. The other groups received TCAA-free water mixed with one of four concentrations (12.5%, 25%, 50%, or 100%) of city tap water containing a known concentration of TCAA.Adapted from Zhang W, et al. J Water Health 7(3):359–371 (2009), with permission from the copyright holders, IWA Publishing.


Drinking water quality: Better biomarker of DBP exposure.

Spivey A - Environ. Health Perspect. (2009)

Study participants were randomly divided into 5 groups. One group served as controls and received TCAA-free bottled water. The other groups received TCAA-free water mixed with one of four concentrations (12.5%, 25%, 50%, or 100%) of city tap water containing a known concentration of TCAA.Adapted from Zhang W, et al. J Water Health 7(3):359–371 (2009), with permission from the copyright holders, IWA Publishing.
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2801181&req=5

f1-ehp-117-a487: Study participants were randomly divided into 5 groups. One group served as controls and received TCAA-free bottled water. The other groups received TCAA-free water mixed with one of four concentrations (12.5%, 25%, 50%, or 100%) of city tap water containing a known concentration of TCAA.Adapted from Zhang W, et al. J Water Health 7(3):359–371 (2009), with permission from the copyright holders, IWA Publishing.

View Article: PubMed Central - PubMed

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

When we drink chlorinated water or shower in it, we’re exposed to chemicals called disinfection by-products (DBPs), which form when organic matter in water reacts with chlorine and other treatment chemicals... Some human epidemiologic studies have found associations between exposure to high levels of DBPs and increased risk of problems such as cancer and reproductive effects... TCAA, on the other hand, persists in the body for several days, offering a longer window for measuring exposure, Zhang says... However, she adds, knowing only water levels of any DBP does not address how much water anyone consumes... In Zhang’s tightly controlled study, for 15 days researchers delivered 3 L of cold tap water that contained a known amount of TCAA to each of the 46 participants... The results showed that blood levels of TCAA made a better biomarker than urinary levels, but for large epidemiologic studies, measuring urine levels is more practical because the sample is collected less invasively, says Zhang, who often conducts field work... She concludes from her results that taking urine measures over two days and averaging them is preferable to a one-day sample, as the results showed better statistical reliability with repeated measures... Susan Richardson, a research chemist with the U.S. Environmental Protection Agency, says the study has many strengths, among them a large group of participants that provided more statistical power than previous studies of TCAA, careful control of TCAA ingestion, and strong correlation between TCAA levels in the ingested drinking water and levels in the participants’ urine and blood... Those elements add up to her opinion that TCAA is ready to be used as a biomarker of DBP exposure in epidemiologic studies... Clifford Weisel, a professor of environmental and occupational health at UMDNJ–Robert Wood Johnson Medical School, suggests the TCAA biomarker would be useful in a study when combined with some measure of other routes of DBP exposure, such as showering and bathing. “These studies show that TCAA will make a potentially good biomarker of ingestion of the haloacetic acids, in particular TCAA... TCAA isn’t a perfect biomarker... It’s not yet known whether it can indicate ingestion of the most dangerous DBPs—other classes of compounds, such as iodinated and brominated compounds, which have been found to be much more toxic than chloroacetic acids... Access to subjects and timing also are important aspects to consider... But overall, researchers call these findings a step in the right direction in an area that needs much more work. “These studies are very important because we have very few biomarkers for disinfection by-products,“ Nieuwenhuijsen says.

Show MeSH