A study of the health status of a population exposed to low levels of hydrogen sulfide (and other geothermal effluents) in Puna, Hawaii : preliminary report

The Kilauea East Rift Zone on the Island of Hawaii is one of the most promising areas for geothermal energy development in Hawaii. Since the drilling of the first successful geothermal wells in 1976, residents in the area have raised concerns that hydrogen sulfide (H2S) released into the atmosphere from geothermal wells may be adversely affecting their health. The emission of H2S gas is currently considered to be the most important public health problem related to the utilization of geothermal energy. Although H2S is unquestionably a toxic gas at high concentrations, experts disagree on the lowest levels at which adverse health effects may occur; very little is known about health effects that may be related to long-term, low-level exposure. In February 1984, the State Department of Health (DOH) conducted a door-to-door health interview survey of a residential community, Leilani Estates, located near a two megawatt geothermal power plant in the Puna District. The primary purposes of this survey were to establish the health status of this community and to compare the health status of this community to another community in Puna, Hawaiian Beaches Estates, and to other areas of Hawaii. Ambient H2S air monitoring data from three monitoring stations in Leilani Estates and a station recently established in Hawaiian Beaches Estates was supplied by the Hawaii Geothermal Project. The health survey utilized a form adapted from the National Health Survey, National Center for Health Statistics, and consists of both demographic and health-oriented questions. This form is used by the Hawaii Health Surveillance Program (HSP), DOH, for the on-going, state-wide Hawaii Health Survey. This allowed for the comparison of the prevalence of reported health conditions in Leilani Estates to the State as a whole and Hawaii County. A supplemental questionnaire form was also administered to gather more detailed information on chronic respiratory conditions and to determine the perception of nuisances (i.e., noise and odor) perceived by residents in Leilani Estates to be associated with geothermal development. Interviews were administered by HSP to 135 (88.8%) of the 152 eligible households in Leilani Estates, representing a total of 350 individuals who live in the area. The rates of all acute and chronic health conditions reported in Leilani Estates were found to be similar to Hawaiian Beaches Estates with the exception of the "common cold," which was substantially higher in Leilani Estates in January 1984. There were no statistically significant differences in other measures of disability in terms of "bed days'' due to chronic conditions and ''activity limitation days over the past month" between these two communities. Perhaps most noteworthy, the rates of chronic respiratory conditions including ''bronchitis/emphysema,'' ''asthma,'' ''hayfever,'' ''sinusitis'' and ''other respiratory system disease" were found to be similar in Leilani Estates and Hawaiian Beaches Estates from January 1983 - January 1984. These conditions have been most often associated with long-term exposure to air pollutants. However, the prevalence rates of a number of acute and chronic health conditions in these study areas were higher than Hawaii County and Hawaii statewide rates reported for 1983, including all chronic respiratory conditions. These differences may be due in part to expected seasonal fluctuation in disease prevalence, differing demographic features that may affect disease prevalence and reporting, and/or other environmental factors (e.g., exposure to pollens or fungi) may be involved and are discussed. Results of air monitoring from three monitoring stations in Leilani Estates during the period extending from January 1983 - January 1984 indicated hydrogen sulfide (H2S) levels ranged from below the reliable detection limit (5 ppb) to ll ppb, based on one-hour averages. Average one-hour levels of H2S in Hawaiian Beaches never exceeded the detection limit. Subsequent air monitoring results have indicated that ambient H2S levels in Leilani Estates may be higher during open, unabated venting of effluent from nearby geothermal wells. Due to venting from natural volcanic fumaroles in the area, the contribution of H2S from geothermal wells was difficult to assess accurately.It could not be determined that H2S produced as a result of geothermal development in the area was responsible for any of the health conditions reported in Leilani Estates. Further studies are required to determine what factors account for the relatively high rates of chronic respiratory conditions reported in the areas surveyed in Puna when compared to average State-wide and County-wide rates. Recommendations are included in this report with regard to the utility of conducting further surveys to address community concerns of adverse health effects associated with geothermal development in Hawaii."The preparation of this report was financed in part by the Coastal Zone Management Act of 1972.