Calculating Workplace WBGT from Meteorological Data: A Tool for Climate Change Assessment

The WBGT heat stress index has been well tested under a variety of climatic conditions and quantitative links have been established between WBGT and the work-rest cycles needed to prevent heat stress effects at the workplace. While there are more specific methods based on individual physiological measurements to determine heat strain in an individual worker, the WBGT index is used in international and national standards to specify workplace heat stress risks. In order to assess time trends of occupational heat exposure at population level, weather station records or climate modelling are the most widely available data sources. The prescribed method to measure WBGT requires special equipment which is not used at weather stations. We compared published methods to calculate outdoor and indoor WBGT from standard climate data, such as air temperature, dew point temperature, wind speed and solar radiation. Specific criteria for recommending a method were developed and original measurements were used to evaluate the different methods. We recommend the method of Liljegren et al. (2008) for calculating outdoor WBGT and the method by Bernard et al. (1999) for indoor WBGT when estimating climate change impacts on occupational heat stress at a population level.     

Unusually high intake and fecal output of cadmium, and fecal output of other trace elements in New Zealand adults consuming dredge oysters

The concentration of cadmium in the New Zealand dredge oyster Tiostrea lutaria (commonly known as a Bluff oyster) is sufficiently high so that the ingestion of just one oyster can more than double a normal daily dietary intake of cadmium for a New Zealand adult. A survey of 75 adults (18-76 years old) associated with the oyster fishing industry in Bluff, Southland, New Zealand, was carried out before and at the end of the oyster season. Preseason intakes (from dietary history questionnaires and from 3-day fecal collections) of cadmium, selenium, zinc, copper, and manganese were normal for a New Zealand adult not consuming Bluff oysters. The subjects were classified according to their reported average oyster consumption during the 6 months of the oyster fishing season; the subjects who consumed more oysters were more likely to smoke cigarettes. The end-season fecal output of cadmium confirmed the reported average oyster intakes: Category I (0-5 oysters/week): 15 +/- 8 (mean +/- SD) micrograms Cd/day; Category II (6-23 oysters/week): 84 +/- 134 micrograms Cd/day; Category III (24-71 oysters/week): 129 +/- 144 micrograms Cd/day; Category IV (72+ oysters/week): 233 +/- 185 micrograms Cd/day. The fecal output of selenium as well was increased by the consumption of many oysters but the fecal outputs of zinc, copper, and manganese were not. Using fecal cadmium excretion to predict dietary cadmium intake, 8-15% of the subjects in this study were identified as having an intake of cadmium which has been associated with an increased prevalence of tubular proteinuria. The highest individual daily fecal excretion of cadmium at the end of the season was 580 micrograms Cd/day, i.e., a daily excretion equivalent to more than 10 times above the weekly intake provisionally considered tolerable (400-500 micrograms Cd/week; WHO, 1972). Continued investigations on this population group will determine whether there are any health consequences of these extremely high cadmium intakes.     

The epidemic of asbestos-related diseases in New Zealand

New Zealand is a small country with a big asbestos disease problem. The lack of action on warnings in the 1960s and 1970s has led to epidemics of mesothelioma and asbestosis, which can be clearly documented via the death and cancer registers. In addition, an uncertain number of lung cancers due to asbestos exposure has occurred. The epidemic started in the 1980s, and will eventually have cost the lives of at least 2000 to 3000 workers. Prevention against ongoing exposures from asbestos installed in buildings is essential, and another key issue for New Zealand is to ensure that fair workers' compensation is provided to all victims of asbestos diseases.     

Adult health: a legitimate concern for developing countries.

Adults, defined here as people between 15 and 59 years of age, in developing countries have a high risk of premature death and suffer from frequent morbidity and high rates of chronic impairment. Their ill health imposes a major burden on health services and large negative consequences on families, communities, and societies. This paper describes the level and impact of adult mortality and morbidity, and highlights some of its characteristics and causes, which in some cases contradict commonly held beliefs. It concludes that "adult health" is a legitimate public health concern for developing countries that is not being addressed. An agenda for remedial research and action is proposed.     

Seasonal variation in acute hospital admissions and emergency room presentations among children in the Australian Capital Territory

AIM: To examine seasonal variation in hospital use for five paediatric conditions of the Australian Capital Territory residents. METHODS: Hospital admissions (1993-2004) and emergency room (ER) presentations (1999-2004) for asthma, croup, bronchiolitis, other respiratory conditions and diarrhoea of children aged <5 years were compared by month and season. RESULTS: The five conditions comprised 14% of admissions and 24% of ER presentations of children aged <5 years. Bronchiolitis (both admissions and ER presentations) were the highest in the 0-1 year age group (>80%) and the other four conditions peaked at 1-2 years. Children aged 0-2 years contributed 66% of diarrhoea, 62% of croup and 44% of other respiratory admissions whereas ER presentations were higher for other respiratory conditions (57%) and lower for croup (47%). Boys showed higher rates of admissions and ER presentations for all conditions except diarrhoea. Strong seasonal associations were apparent. Incident rate ratios of admissions were significantly higher in autumn compared with summer for asthma and croup whereas bronchiolitis and other respiratory conditions admissions were the highest in winter. Diarrhoea admissions were the highest in spring. ER presentations of the five conditions also showed similar associations with season. CONCLUSION: Hospital admissions and ER presentations of these five conditions showed strong seasonal patterns, knowledge of which could contribute to improved resource planning (staffing) to meet expected increases in demand for services and scheduling of elective admissions. These findings could be extended to develop a model for forecasting hospital use and to explore the causes of these diseases to ameliorate seasonal effects.     

Daily mortality in relation to weather and air pollution in Christchurch, New Zealand

OBJECTIVE: To investigate the relationship between the daily number of deaths, weather and ambient air pollution. METHOD: An ecological study. We assembled daily data for the city of Christchurch, New Zealand (population 300,000) from June 1988 to December 1993. We used Poisson regression models, controlling for season using a parametric method. RESULTS: Above the third quartile (20.5 degrees C) of maximum temperature, an increase of 1 degree C was associated with a 1% (95% CI: 0.4 to 2.1%) increase in all-cause mortality and a 3% (0.1 to 6.0%) increase in respiratory mortality. An increase in PM10 of 10 micrograms/m3 was associated (after a lag of one day) with a 1% (0.5 to 2.2%) increase in all-cause mortality and a 4% (1.5 to 5.9%) increase in respiratory mortality. We found no evidence of interaction between the effects of temperature and particulate air pollution. CONCLUSIONS: High temperatures and particulate air pollution are independently associated with increased daily mortality in Christchurch. The fact that these results are consistent with those of similar studies in other countries strengthens the argument that the associations are likely to be causal. IMPLICATIONS: These findings contribute to evidence of health consequences of fuel combustion, both in the short term (from local air pollution) and in the long term (from the global climatic effects of increased atmospheric CO2).