An Estimate of Population Exposures Due to Radon in Public Water Supplies in the Area of Houston, Texas

Prichard, Howard M.; Gesell, T.F.

doi:10.1097/00004032-198110000-00002

Cited by 46 publications

(14 citation statements)

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“…1 " 5 In addition, there have been studies of indoor radon exposure as a result of water-born radon-222, another highly volatile substance. 6 "* These studies indicate that exposure to volatile chemicals in tap water by inhalation may be as large as or larger than exposure from fluid ingestion. The contaminants available in the indoor air are released by showers, baths, toilets, dishwashers, washing machines, and cooking.…”

Section: Introductionmentioning

confidence: 96%

The Transfer of Trichloroethyene (TCE) from a Shower to Indoor Air: Experimental Measurements and Their Implications

McKone

Knezovich

1991

Journal of the Air & Waste Management Association

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Experiments were performed to measure the transfer of trlchloroethylene (TCE), a volatile organic compound (VOC), from tap water In showers to Indoor air. In these experiments, the loss of TCE from tap water in the shower is based on the difference between Influent and effluent concentrations. We have developed and previously published a three-compartment model, which we use to simulate the 24-h concentration history of VOCs in the shower, bathroom, and remaining household volumes resulting from the use of contaminated tap water. An important input to this model is the transfer efficiency of the VOC from water to air. The experiments reveal that the transfer efficiency of TCE from shower water to air has an arithmetic mean value of 61 percent and an arithmetic standard deviation of 9 percent. Analysis of the results shows that there Is no statistically significant difference between the transfer efficiency measured with hot (37°C) or cold (22°C) shower water and that there Is no statistically significant change In transfer efficiency with time during a 20-mln shower. The implications for exposure assessment are considered.Estimation of human exposure to organic chemicals transferred from tap water in showers to indoor air requires answers to several questions, among them- (1) what is the contaminant concentration in the water supply, (2) what fraction of the dissolved contaminant is transferred from water to air in the shower stall, (3) how much water is used in a typical shower, (4) what is the resulting concentration in Implications Efforts to assess human exposure to contaminated tap water have revealed that significant exposures to volatile organic compounds (VOCs) can occur from the indoor inhalation pathway-primarily in showers. At air-water interfaces, mass transfer of chemicals reflects the resistance through both the liquid and gas phases and is difficult to predict from first principles. However, basic mass transfer properties, such as diffusion coefficients, can be accurately estimated. The theoretical dependence of transfer efficiency on these properties makes plausible estimates of relative transfer efficiency through the scaling of mass transfer parameters from one chemical to another. The lack of temperature dependence in our measurements of transfer efficiency supports the premise that for volatile compounds transfer efficiency is limited by liquid-phase mass transfer (which is more temperature insensitive) and not by gas-phase mass transfer (which is more sensitive). For households using tap water contaminated with TCE, the results here indicate that inhalation exposures in showers could be as large as or larger than a conservative estimate of ingestion exposure. The assumption that 70-kg adult consumes 2 L per day of tap water is considered a conservative estimate of ingestion exposure. Our experimental results suggest that inhalation exposures in showers could be equivalent to an ingestion contact of 1 to 4 L. the shower stall and bathroom air, and (5) how much time is spent in contact with th...

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Section: Introductionmentioning

confidence: 96%

The Transfer of Trichloroethyene (TCE) from a Shower to Indoor Air: Experimental Measurements and Their Implications

McKone

Knezovich

1991

Journal of the Air & Waste Management Association

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“…He points out the need for refining present estimates of indoor air exposure to VOCs derived from potable water sources by, inter alia, more accurately accounting for the chemical characteristics that affect the rate and extent of volatilization. In order to account for the different properties of VOCs, McKone (3,5,6) proposed a relationship which adjusts the measured transfer 2 ,it efficiency (the fraction volatilized) for radon (7,8) to that for any VOC using the Henry's law constant and liquid and gas diffusivities. Although the relationship was only 'intended to be approximate it does not adequately account for gas-phase resistance (9).…”

Section: Introductionmentioning

confidence: 99%

Applying the two-resistance theory to contaminant volatilization in showers

Little¹

1992

Environ. Sci. Technol.

103

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“…The most obvious route of exposure to contaminants is by ingestion; however, dermal and inhalation exposure may also occur within the home. Several studies have shown that showering increases the likelihood that an organic compound will be volatilized, resulting in human exposure beyond that occurring from ingestion (Backer et al, 2000; Giardino & Hagman, 1996;Kerger et al, 2000;Moya et al, 1999;Prichard & Gesell, 1981). For example, in one study, the blood levels of trihalomethane were highest among individuals showering for 10 min, intermediate for individuals bathing for 10 min, and lowest among those who drank 1 L water from the same source over a 10-min period (Backer et al, 2000).…”

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confidence: 99%

Particle Size Distribution and Inhalation Dose of Shower Water Under Selected Operating Conditions

Zhou

Benson

Irvin

et al. 2007

Inhalation Toxicology

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Showering produces respirable droplets that may serve to deposit pollutants such as trihalomethane decontamination products, heavy metals, inorganic salts, microbes, or cyanoacterial toxins within the respiratory tract. The extent and importance of this route of indoor exposure depend on the physical characteristics of the aerosol as well as the pollutant profile of the source water. The purpose of this study was to characterize shower-generated aerosols as a function of water flow rate, temperature, and bathroom location. Aerosols were generated within a shower stall containing a mannequin to simulate the presence of a human. Using hot water, the mass median diameter (MMD) of the droplets inside the shower and in the bathroom were 6.3-7.5 um and 5.2-6 µm, respectively. Size was independent of water flow rate. The particle concentration inside the shower ranged from 5 to 14 mg/m 3 . Aerosols generated using cold water were smaller (2.5-3.1 µm) and concentrations were lower (0.02-0.1 mg/m 3 ) inside the shower stall. No aerosols were detected in the bathroom area when cold water was used. The International Commission on Radiological Protection model was used to estimate water deposition in the respiratory tract. For hot water, total deposition ranged from 11 to 14 mg, depending on water flow rate, with approximately 50% of this deposited in the extrathoracic region during assumed mouth breathing, and greater than 86% when nose breathing was assumed. Alveolar deposition was 6-10% and 0.9% assuming oral and nasal breathing, respectively. The consequences deposition of shower water droplets will depend on the nature and extent of any pollutants in the source water.One potential source of human exposure to environmental pollutants is through chemically contaminated domestic tap water. The most obvious route of exposure to contaminants is by ingestion; however, dermal and inhalation exposure may also occur within the home. Several studies have shown that showering increases the likelihood that an organic compound will be volatilized, resulting in human exposure beyond that occurring from ingestion (Backer et al., 2000; Giardino & Hagman, 1996;Kerger et al., 2000;Moya et al., 1999;Prichard & Gesell, 1981). For example, in one study, the blood levels of trihalomethane were highest among individuals showering for 10 min, intermediate for individuals bathing for 10 min, and lowest among those who drank 1 L water from the same source over a 10-min period (Backer et al., 2000). These results support the hypothesis that showering is an important route of exposure for trihalomethanes, and possibly other volatile contaminants in tap water. Copyright © Informa HealthcareAddress correspondence to Yue Zhou, 2425 Ridgecrest Dr. SE, Albuquerque, NM 87108, USA. yzhou@lrri.org. Publisher's Disclaimer: Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article maybe used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribut...

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An Estimate of Population Exposures Due to Radon in Public Water Supplies in the Area of Houston, Texas

Cited by 46 publications

References 1 publication

The Transfer of Trichloroethyene (TCE) from a Shower to Indoor Air: Experimental Measurements and Their Implications

The Transfer of Trichloroethyene (TCE) from a Shower to Indoor Air: Experimental Measurements and Their Implications

Applying the two-resistance theory to contaminant volatilization in showers

Particle Size Distribution and Inhalation Dose of Shower Water Under Selected Operating Conditions

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