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Exogenous and endogenous determinants of blood trihalomethane levels after showering.

Backer LC, Lan Q, Blount BC, Nuckols JR, Branch R, Lyu CW, Kieszak SM, Brinkman MC, Gordon SM, Flanders WD, Romkes M, Cantor KP - Environ. Health Perspect. (2008)

Bottom Line: We did not observe the clustering of blood THM concentrations observed in our earlier study.We found that environmental THM concentrations were important predictors of blood THM concentrations immediately after showering.For example, the chloroform concentration in the shower stall air was the most important predictor of blood chloroform levels 10 min after the shower (p < 0.001).

View Article: PubMed Central - PubMed

Affiliation: National Center for Environmental Health, Centers for Disease Control and Prevention, Chamblee, GA 30341, USA. lfb9@cdc.gov <lfb9@cdc.gov>

ABSTRACT

Background: We previously conducted a study to assess whether household exposures to tap water increased an individual's internal dose of trihalomethanes (THMs). Increases in blood THM levels among subjects who showered or bathed were variable, with increased levels tending to cluster in two groups.

Objectives: Our goal was to assess the importance of personal characteristics, previous exposures, genetic polymorphisms, and environmental exposures in determining THM concentrations in blood after showering.

Methods: One hundred study participants completed a health symptom questionnaire, a 48-hr food and water consumption diary, and took a 10-min shower in a controlled setting. We examined THM levels in blood samples collected at baseline and 10 and 30 min after the shower. We assessed the significance of personal characteristics, previous exposures to THMs, and specific gene polymorphisms in predicting postshower blood THM concentrations.

Results: We did not observe the clustering of blood THM concentrations observed in our earlier study. We found that environmental THM concentrations were important predictors of blood THM concentrations immediately after showering. For example, the chloroform concentration in the shower stall air was the most important predictor of blood chloroform levels 10 min after the shower (p < 0.001). Personal characteristics, previous exposures to THMs, and specific polymorphisms in CYP2D6 and GSTT1 genes were significant predictors of both baseline and postshowering blood THM concentrations as well as of changes in THM concentrations associated with showering.

Conclusion: The inclusion of information about individual physiologic characteristics and environmental measurements would be valuable in future studies to assess human health effects from exposures to THMs in tap water.

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Related in: MedlinePlus

THM concentrations in shower water. Data are presented by study ID number in numeric and chronologic order over the 12-week study period (n = 99).
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f1-ehp0116-000057: THM concentrations in shower water. Data are presented by study ID number in numeric and chronologic order over the 12-week study period (n = 99).

Mentions: The distribution of THMs in water samples by consecutive study participant number over the 12-week study period is shown in Figure 1. Bromoform levels were > 6 μg/L for all but one of the first 12 participants and < 2 μg/L for the remaining participants. The drop in bromoform concentration during the study was likely the result of unusually high rainfall that occurred in Pittsburgh at the time of the study. It is likely that the unusually high water volume diluted the local water source, thus diluting tap-water bromine concentrations. Despite the very low levels of bromoform in the water, we were able to detect bromoform in 75 of the baseline blood samples and in 98 of the 10-min postshowering blood samples. The concentrations of mono-and dibrominated compounds also decreased over the study period. Over the study period, chloroform levels in shower water varied from < 40 μg/L to nearly 100 μg/L.


Exogenous and endogenous determinants of blood trihalomethane levels after showering.

Backer LC, Lan Q, Blount BC, Nuckols JR, Branch R, Lyu CW, Kieszak SM, Brinkman MC, Gordon SM, Flanders WD, Romkes M, Cantor KP - Environ. Health Perspect. (2008)

THM concentrations in shower water. Data are presented by study ID number in numeric and chronologic order over the 12-week study period (n = 99).
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2199304&req=5

f1-ehp0116-000057: THM concentrations in shower water. Data are presented by study ID number in numeric and chronologic order over the 12-week study period (n = 99).
Mentions: The distribution of THMs in water samples by consecutive study participant number over the 12-week study period is shown in Figure 1. Bromoform levels were > 6 μg/L for all but one of the first 12 participants and < 2 μg/L for the remaining participants. The drop in bromoform concentration during the study was likely the result of unusually high rainfall that occurred in Pittsburgh at the time of the study. It is likely that the unusually high water volume diluted the local water source, thus diluting tap-water bromine concentrations. Despite the very low levels of bromoform in the water, we were able to detect bromoform in 75 of the baseline blood samples and in 98 of the 10-min postshowering blood samples. The concentrations of mono-and dibrominated compounds also decreased over the study period. Over the study period, chloroform levels in shower water varied from < 40 μg/L to nearly 100 μg/L.

Bottom Line: We did not observe the clustering of blood THM concentrations observed in our earlier study.We found that environmental THM concentrations were important predictors of blood THM concentrations immediately after showering.For example, the chloroform concentration in the shower stall air was the most important predictor of blood chloroform levels 10 min after the shower (p < 0.001).

View Article: PubMed Central - PubMed

Affiliation: National Center for Environmental Health, Centers for Disease Control and Prevention, Chamblee, GA 30341, USA. lfb9@cdc.gov <lfb9@cdc.gov>

ABSTRACT

Background: We previously conducted a study to assess whether household exposures to tap water increased an individual's internal dose of trihalomethanes (THMs). Increases in blood THM levels among subjects who showered or bathed were variable, with increased levels tending to cluster in two groups.

Objectives: Our goal was to assess the importance of personal characteristics, previous exposures, genetic polymorphisms, and environmental exposures in determining THM concentrations in blood after showering.

Methods: One hundred study participants completed a health symptom questionnaire, a 48-hr food and water consumption diary, and took a 10-min shower in a controlled setting. We examined THM levels in blood samples collected at baseline and 10 and 30 min after the shower. We assessed the significance of personal characteristics, previous exposures to THMs, and specific gene polymorphisms in predicting postshower blood THM concentrations.

Results: We did not observe the clustering of blood THM concentrations observed in our earlier study. We found that environmental THM concentrations were important predictors of blood THM concentrations immediately after showering. For example, the chloroform concentration in the shower stall air was the most important predictor of blood chloroform levels 10 min after the shower (p < 0.001). Personal characteristics, previous exposures to THMs, and specific polymorphisms in CYP2D6 and GSTT1 genes were significant predictors of both baseline and postshowering blood THM concentrations as well as of changes in THM concentrations associated with showering.

Conclusion: The inclusion of information about individual physiologic characteristics and environmental measurements would be valuable in future studies to assess human health effects from exposures to THMs in tap water.

Show MeSH
Related in: MedlinePlus