Hydrogen sulfide and health in Rotorua, New Zealand : final report March 1984 - September 1985

Siegel, Sanford Marvin
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Department of Botany, University of Hawaii at Manoa
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Approximately 46,000 people live in the Rotorua Urban Area, about one-quarter of Polynesian ancestry. The city has now existed for more than 125 years, but the area's Maori history extends back to the 14th century A.D. The mild climate, recreational features, thermal sites and generally pleasant and comfortable lifestyle attract about 500,000 tourists annually. Tourism is a major industry, although agriculture and sheep ranching are economically important. In addition to the rural countryside and forested hills surrounding the city, Lake Rotorua itself is scenic and popular for boating, fishing and nearby camping. Sulphur Bay at the most southerly end of the Lake is a recognized wildlife refuge area which includes nesting (breeding) populations still on the increase in numbers. In many respects, Rotorua as a place for people and a congenial place of relatively low density with a keen appreciation for natural beauty and conservation is quite reminiscent of Hawaii - especially the Big Island. And like the Big Island, Rotorua lies in a geothermally active area. In the city per se the highest geothermal technology is direct heat usage for homes, hotels, businesses, schools, hospitals and of course, motels. Every tourist establishment has its advertised spas, saunas or thermal pools, hot and smelly. Bore hole emissions are not abated - and there are hundreds of than. Nevertheless, the greatest sources of hydrogen sulfide are the natural vents, fissures and fumaroles. Rotorua always smells of H2S. It was this considerable set of parallels, even overlaps that prompted the comparison of Rotorua and the Puna District geothermal energy development zone in the hope and conviction that the expressed concerns of residents there about geothermal air pollution especially H2S hazards could be answered by New Zealand experience. Within the kilometer downwind of HGP-A, along Leilani Drive. the H2S level has rarely reached 10 ppb, with an average of less than 5 ppb, the most realistic odor threshold for the more sensitive individuals. Our survey of atmospheric H2S in Rotorua over the period of May 1984 - July 1985 has revealed a number of areas that always have H2S above the 10 ppb level. In the 21 sq. km. surveyed, the western reaches of the city fell below 5 Rb, but nearly half the city lakeward exceeded 10 ppb at every visit; about 30% of the survey area fell between 30 and 300 ppb; and 15-20%, exceeded 300 ppb. These figures, based on daylight sampling are not corrected for diurnal variation and must not be considered peak values. Sane public locations heavily used in downtown Rotorua exceeded 2000 ppb constantly. In all, of 24 residential areas including Maori centers, 67% experienced H2S, about 40% beinq above 30 ppb. Of school/playground and hospital sites, 21 locations in all, 14 experienced continuous H2S exposure, 50% being above 30 ppb. Overall, the "norm" for Rotorua lies above 100 ppb for more than 50% of the time. and possibly well above that time-concentration range if diurnal corrections could be made. Thus the Rotorua urban Area runs over 30-fold higher H2S levels than the Puna Area closest to HGP-A. But Rotorua has many "hot spots" that in our related experience always run 100-1000 times higher than the OOP-A average, and these areas cannot be simply worked into an average and forgotten otherwise. By local standards in Lower Puna. and all other areas of Hawaii at some district from the active zone in Hawaii Volcanoes National Park, the Rotorua exposure is strong to severe. What there is the health picture for their community with residents of Anglo-European and Polynesian ancestry over every generation? In seeking answers the picture of the Maori as a disadvantaged minority with a history of high mortality from respiratory disease, asthma, lung cancer and other ailments was kept in mind. "Early Years," including neonatal, post-natal and age 1-4; congenital birth defects, tuberculosis, lung cancer, bronchial disorders, pneumonia, and other diseases not involving the pulmonary region, were evaluated using data from the New Zealand Health statistics center. Male and female, Maori and non-Maori and age-specific factors were noted. Most useful was the comparison of Rotorua Urban Area with other New Zealand communities (13 or 22) all non-geothermal. Here Standardized Mortality Ratios (SMR's) were used. These are age-adjusted ruling out (an important source of) local community differences. The result of these data searches evaluations and comparisons is simple and we believe uncomplicated: There is no disease correlation or birth correlation in the Rotorua urban Area that cannot be found in equal or higher incidence in at least 2 other communities that have no geothermal activity and no detectable H2S. Further, there are many examples, both in respiratory and degenerative disease areas for males, females, Maori and non-Maori that point to Rotorua as one of New Zealands's healthy communities. We conclude that the average level of ambient H2S in and around HGP-A could easily be increased 30-fold (and perhaps more) at current abatement state of the art without any hazard to human health.* *And other data appended suggests that the native (and cultivated) plants and indigenous bird populations are also "safe" at levels far above B3P-A.
Prepared for Hawaii Natural Energy Institute and Hawaiian Electric Industries September 1, 1985
air quality, hydrogen sulfide, health, Rotorua, New Zealand
Siegel SM. 1985. Hydrogen sulfide and health in Rotorua, New Zealand: Final report March 1984 - September 1985. Honolulu (HI): Botany Department, University of Hawaii at Manoa.
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