Clean Technologies and Environmental Policy

, Volume 14, Issue 4, pp 551–564 | Cite as

A GIS-based evaluation of risks due to trihalomethane exposure during showering in coastal Texas

Original Paper


Disinfection of water supplies with chlorine is essential to water treatment, but can lead to the formation of trihalomethanes (THMs) in the presence of natural organic matter. Exposure to THMs via inhalation during daily activities such as showering can significantly increase cancer risks. An innovative decision support system was developed for evaluating THM exposure and risks in water supplies in the Gulf Coast region of Texas by combining a shower THM volatilization model, geospatial analysis techniques, and risk assessment methodologies. Based on THM data from fourteen locations in the region, a power-law equation was developed to predict the formation of THMs in groundwater wells. Health risks associated with THMs in the water supplies of the Gulf Coast of Texas were evaluated. Cancer risks were found to vary from 7.14 × 10−7 to 7.75 × 10−6. While two-thirds of the geographical area was below the threshold risk of 1 × 10−6, it accounted for only a tenth of the total population. Metropolitan areas such as Corpus Christi and McAllen, which currently use surface water sources, and Houston, which is seeking alternate water sources due to subsidence issues, were found to have significant cancer risks (in excess of one in a million). A third of the population of Texas is housed in the Gulf Coast region, and with more population migration toward the metropolitan areas, it is recommended that water resource management decisions be made taking into consideration both the quantity and quality of water available.


Trihalomethanes Risk assessment Geostatistics Water resource planning Groundwater Texas Gulf Coast Inhalation GIS 

List of symbols


THM concentration in cold water (μg/l)


THM concentration in heated water (μg/l)


THM concentration in air (μg/l)


Average THM concentration in air (μg/l)


Initial THM concentration in air prior to shower (μg/l)


Growth rate of THM in cold water (min−1)


Growth rate of THM in heated water (min−1)


Absorption efficiency through respiratory system


Air inhalation rate (l/min)


Duration of shower (min/shower)


Shower frequency (showers/day)


Exposure frequency (days/year)


Exposure duration (years)


Body weight (kg)


Averaging time (days)


Flow rate of water into stall (m3/min)


Volume of shower stall (m3)


Temperature of cold water (°C)


Temperature of heated water (°C)


Air exchange rate between shower and bathroom (min−1)


THM transfer percentage from water to air phase


Area of skin exposed to water (m2)


Permeability of THMs through skin (m2/min)


Chronic daily intake (mg/(kg d))


Reference dose (mg/(kg d))


Slope factor (kg d/mg)


Hazard index



This material is based upon work supported by the National Science Foundation under Grant no. HRD-0734850: Center for Research Excellence in Science and Technology, Research on Environmental Sustainability in Semi-Arid Coastal Areas (CREST-RESSACA). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation. The anonymous reviewers are also thanked for their constructive comments, which greatly enhanced the readability of the manuscript.


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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.Department of Environmental EngineeringTexas A&M University-KingsvilleKingsvilleUSA

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