Harmful substances in groundwater could cause adverse health effects when entering into human body via drinking water, direct inhalation or dermal contact during showering and washing. Currently, the exposure parameters used in Taiwan are majorly based on those established by the U.S. From the standpoint of the risk assessment, however, differences in ethnicity, life style, cultural background, and physiological attributes can all render the results of the risk assessment unreasonable. Since there still lacks a systematic investigation on the localized inhalation rate that heavily depends on ages, genders, lung structure, lung function, and breathing patterns, this project aims at establishing these parameters during resting and showering using a portable gas exchange analyzer (COSMED K5). The estimated parameters will also be applied to evaluate the inhalation exposure to pollutants in contaminated sites for Taiwanese. There were 100 participants recruited in this study. The results of respiratory rates were 13.2 ± 2.91 m3/day and 14.7 ± 3.18 m3/day for resting and showering conditions, respectively. Based on the results, the current default values recommended by the Soil and Ground Information Management System (SGM system) for the respiratory rates during resting (17.14 m3/day) and showering (24.0 m3/day) were both overestimated. In addition, this study also found that the respiratory rates were influenced by genders, ages, and physiological conditions. The COSMED K5 was used to evaluate the energy expenditure, oxygen uptake factor, and ventilatory quotient. The localized modified equations for the respiratory rates were established for the participants aged 20-40. Besides, in order to verify the suitability of using accelerometer as an alternative for estimating respiratory rates for different activities, this study also analyzed the correlation between the acceleration value obtained by the accelerometer and the respiratory rates measured by the portable energy metabolism system. The result (r=0.766; p<0.01) showed that the accelerometer was suitable for predicting the respiratory rates under the showering scenario. The groundwater contaminated sites in Pingtung were selected to estimate the health risk for adults in age 20-40 exposing to groundwater contaminated by the chlorinated organic compounds. We found that the risk calculated by the SGM system default values may be overestimated. A significant difference in the physiological structures between men and women can also result in the different exposure dosages based on our results. We suggest that the SGM system to provide, in addition to the default values, the distribution of respiratory rates established in this study for estimating the human risk assessment in the future.

Local exposure factors, inhalation rate, groundwater, health risk assessment