Indoor air pollution from biomass combustion and respiratory symptoms of women and children in a Zimbabwean village.

UNLABELLED: Rural areas of developing countries are particularly reliant on biomass for cooking and heating. Women and children in these areas are often exposed to high levels of pollutants from biomass combustion that is associated with a range of respiratory symptoms. Domestic exposure to carbon monoxide (CO) and respirable particles (RSPs) in association with respiratory symptoms among women and children in Zimbabwe was investigated in 48 households. Health status and household characteristics were also recorded. In this study, indoor levels of CO and RSPs exceeded World Health Organization (WHO) air quality guidelines in over 95% of kitchens. The level of indoor air pollutants was associated with the area of kitchen windows and the length of cooking time combined with the level of fire combustion. Prevalence of respiratory symptoms was 94% for women and 77% for children. In addition, women reporting respiratory symptoms were exposed to higher levels of RSPs when compared with those reporting no respiratory symptoms. The study results indicated that levels of indoor air pollutants in rural Zimbabwe may contribute to respiratory symptoms in both women and children. PRACTICAL IMPLICATIONS: Levels of respirable particles and carbon monoxide in kitchens in rural Zimbabwe are unacceptably high and measures to reduce levels should be undertaken. Based on the study findings, recommendations for increasing the area of kitchen windows may be considered as a practical method of reducing indoor air pollutants in rural Zimbabwe.

Natural disasters in developing countries: an environmental health perspective.

Inadequate water supply and sanitation services underscore the lives of billions of people in the developing world. This situation is compounded when natural disasters strike because the existing infrastructure is destroyed, and scarce resources are diverted to cope with the crisis and then the reconstruction. In comparison, many industrialised countries have prevention measures in place to reduce the risk of damage, and policies and actions in place to reduce the impact of the next disaster. Environmental health professionals from both government and non-government organisations can play an important role in disaster prevention, mitigation and response in these situations. However, the success of environmental health programmes does depend on the existing social inequities. This is because in many developing countries, the poorest and least powerful people already live in a situation with poor water supply and sanitation, which is compounded by natural disasters.

Domestic exposure to formaldehyde significantly increases the risk of asthma in young children.

Concern has arisen in recent years about indoor air pollution as a risk factor for asthma. Formaldehyde exposure was examined in relation to asthma among young children (between 6 months and 3 yrs old) in a population-based control study carried out in Perth, Western Australia, between 1997-1999. An association between exposure to formaldehyde and asthma in young children has been suggested. Cases (n=88), whose parents were recruited at Princess Margaret Hospital Accident and Emergency Dept (Perth, Western Australia), were children discharged with asthma as the primary diagnosis. Controls (n=104), who were children in the same age group without asthma diagnosed by a doctor, were identified from birth records through the Health Dept of Western Australia (Perth, Western Australia). Health outcomes for the children were studied using a respiratory questionnaire and skin-prick tests. Formaldehyde, average temperature and relative humidity were measured on two occasions, winter (July-September 1998) and summer (December 1998-March 1999) in the child's bedroom and in the living room. The study found seasonal differences in formaldehyde levels in the children's bedrooms and living rooms with significantly greater formaldehyde exposure during the summer period for case and control subjects. The generalised estimating equation model showed that children exposed to formaldehyde levels of > or = 60 microg x m(-3) are at increased risk of having asthma. The results suggest that domestic exposure to formaldehyde increases the risk of childhood asthma.

The content and efficacy of environmental public health journal homepages.

The information on several environmental public health journal homepages has been assessed for its quality and quantity, using selected key criteria. These criteria included the extent of text available, the ability to search the website, the table of contents free via email, and the presence of hyper-links. A high degree of variability is seen, with services and facilities offered ranging from none to the entire journal available for no fee. The journal homepages that are the most comprehensive are those that are associated with major institutions and hence financed by contributions from their members or public money, i.e. the British Medical Association, the World Health Organisation and the US National Institute of Environmental Health Sciences. The journal homepages associated with these institutions offered full text of both current and archived issues as well as additions such as the ability to search other sites, web links, and in some cases hyper-linked references and information on related articles. The provision of text on the Internet should be an essential aim for all journal Homepages, to ensure fast and effective conveyance of information to health professionals.

Occupational health and safety curricula: the factors that decide -an Australian experience.

Societal, economic and other changes in recent years have resulted in both an increased level and diversity of education and training in occupational health and safety in Australia. Consideration has been given to the key skills and knowledge required by those who take tertiary level courses and who practise as specialists and generalists in the field of occupational health and safety. The curricula and mode of implementation of these courses are determined by the needs of employers, increased emphasis on quality management systems, the prevailing work climate including information technology, communication and legislative requirements all in the context of a rapidly changing tertiary education system.

A review of environment health impact assessment.

The general community is becoming increasingly aware of the effect that developments, either in industry or residential areas, are having on the surrounding environment. That people have a safe place to work and live in, is important to the overall welfare of a community. Currently, assessment of the health impact of proposed developments is somewhat limited, and is usually made with reference to potential fatalities, rather than general morbidity. Assessment of the environmental health impact of a development is most often concentrated on a particular aspect, such as a method of transportation of chemicals, or of manufacturing a certain component--those areas which are seen as having the greatest risks associated with them. Rarely is a broad screening of potential environmental health impacts included.

Toxicology and the general practitioner.

The media often portray chemicals of any description in eye-catching headlines so it is increasingly important to educate the public about the factors that affect the toxicity of a chemical substance, so that people can make informed choices about the risks and benefits posed by these substances. Toxicology is an important tool in public health and regulatory decision making, but there are limitations which often need to be addressed. There are questions in this area that science cannot reasonably answer, and the public should be made more aware of the reasons. This article examines these issues.

The interaction of lead exposure and pregnancy.

The toxic effects of low-level lead exposure have been the subject of a good deal of research and media attention in recent times. In most countries, the acceptable occupational exposure limit for lead is being progressively decreased as the adverse health effects of lead are being identified at levels approaching those found in non-occupational environments. Due to the sensitive nature of the fetus to hazardous substances, the exposure to lead of the unborn child via maternal sources is of critical concern. Preterm delivery, congenital abnormalities and decreases in growth stature have all been associated with prenatal lead exposure at "acceptable" levels. There is an accumulation of evidence which indicates that maternal exposures prior to conception can play an important role in determining blood lead levels during pregnancy. In light of these observations the practice of removing the pregnant woman from lead sources may be of questionable value with regards to providing sufficient protection for the fetus. This article reviews the relevant literature pertaining to the mobilization of lead from bone during pregnancy and the toxicity of low-level lead exposure to the fetus, and briefly discusses some factors which may affect this toxicity.

Maternal hair zinc and neural tube defects: no evidence of an association from a case-control study in Western Australia.

In a case-control study of isolated neural tube defects in Western Australia, zinc was estimated by flame spectrophotometry in post-partum hair specimens from 54 mothers of infants with neural tube defects, and from 128 mothers of normal infants. The distribution of the estimates of zinc was divided into quartiles. Using the lowest quartile as the reference group, the crude odds ratios (and their 95% confidence intervals) for quartiles two through four were 1.07 (0.44, 2.59), 1.02 (0.41, 2.56), and 0.70 (0.28, 1.73). Adjustment for several potential confounding variables (parental country of birth, social class, previous pregnancy outcome, interval between previous and index pregnancy, pregnancy order, and interval from birth to interview) made little difference to the odds ratios. This study provides no evidence of an association between post-partum, maternal hair zinc and offspring with neural tube defects.

Patterns of pesticide usage by cereal crop farmers in Western Australia.

In Western Australia there has been an increase in the use of herbicides in recent years due to a change in farming practices. This change, together with more general public concern over exposure to chemicals, has resulted in farmers expressing concern over the possible long term health effects from exposure to herbicides. As part of a long term study of the possible health effects from such exposure, a survey was carried out to establish the extent of pesticide use within the cereal farming community of Western Australia. Of the 9,408 properties surveyed, 2,921 responses were received which represents a 32.2% response rate. The results indicate that a wide range of chemicals are used as insecticides, fumigants, seed dressings, seed pickles, herbicides, and rodent poisons. At the time of the survey in 1985, products containing prespruf and 1,1,1-trichloro-2,2-bis (p-chlorophenyl)ethane (DDT) were the most popular insecticide, and products containing diquat, diclofop-methyl, chlorsulfuron and glyphosate as active ingredients represented the four most popular herbicides.

The influence of dietary citrate on the absorption and retention of orally ingested lead.

The influence of dietary citrate on the toxicity of orally ingested lead was investigated in male weanling mice. Twenty-four animals were divided into three equal groups. Group 1 served as controls, groups 2 and 3 were given 20 micrograms lead (as lead acetate) per g/diet, group 3 also received 4% sodium citrate in the diet. After 5 weeks, blood and tissue lead levels were measured. All mice given lead-supplemented diets had higher concentrations of lead in blood, liver, kidney, brain and bone than the control group, but the increase was significantly greater in the group given 4% sodium citrate in the diet. This work demonstrated that dietary citrate at levels which can be present in food significantly increases lead toxicity.

Mortality of fire fighters in Western Australia.

All except 17 (1.7%) of 990 fire fighters employed by the Western Australian Fire Brigade between 1 October 1939 and 31 December 1978 were successfully followed up to 31 December 1978. Mortality from all causes was less than expected (SMR 0.80 with 95% confidence interval 0.67 to 0.96). There was evidence of the healthy worker effect but none that mortality increased with increasing duration of employment. A small proportional excess of deaths from road traffic accidents ( SPMR 1.66) appeared to be unrelated to fire service. Deaths from other accidents, poisonings, and violence were significantly less than expected (SMR 0.35 with 95% confidence interval 0.10 to 0.90) and may indicate an effect of training and experience on accident proneness. There was no evidence of increased mortality from cardiovascular or respiratory disease, or from any other cause.

The influence of dietary fat on the toxicity of orally ingested lead in rats.

The influence of dietary fat on the toxicity of orally ingested lead was investigated. Groups of ten male weanling Wistar rats were maintained on diets providing 11.5, 20, 40 or 60% of energy from fat for 8 wk. All diets were supplemented with a low level of lead--1.25 mg Pb (as lead acetate) per 1000 kJ energy in the diet. Groups receiving 11.5 and 20% of energy as fat had similar lead levels for each tissue studied. Raising the fat level to 40 or 60% of energy resulted in significant increases in tissue-lead concentrations with each increment in dietary fat. The groups receiving 60% of energy as fat had more than twice the level of lead in the femur, kidney, liver and brain than the control rats maintained on the diet containing 11.5% energy as fat, even though the amount of lead ingested was the same for all groups. delta-Aminolaevulinic acid dehydratase activity was not affected when dietary fat was increased from 11.5 to 20%. There was a significant reduction in activity when fat was increased to 40 or 60% of energy. Free erythrocyte protoporphyrin was not affected by the level of dietary fat. This work demonstrates that increasing the level of dietary fat significantly increases lead toxicity and indicates the need for further research on the interaction between dietary factors and lead toxicity.

The influence of dietary phosphate on the toxicity of orally ingested lead in rats.

The influence of elevated dietary phosphate on the toxicity of orally ingested lead was investigated in male weanling Wistar rats. Two groups of 20 rats were fed diets containing either adequate (0.5%) or high (1.2%) levels of phosphorus (as phosphates). Half of the rats on each level of phosphorus were given 20 micrograms lead (as lead acetate)/g dry diet. After 8 wk, biochemical tests for lead toxicity were carried out and tissue-lead levels were measured. All of the rats given lead-supplemented diets had higher concentrations of lead in bone, brain, kidney and liver than those given diets without added lead but the increase was significantly greater in all tissues in the group given the 1.2% phosphorus diet. Lead supplementation increased the levels of free erythrocyte protoporphyrin and decreased the activity of delta-aminolaevulinic acid dehydratase. The lead-induced increase in the level of free erythrocyte protoporphyrin was no greater in the high-phosphate group than in the low-phosphate group but the decrease in delta-aminolaevulinic acid dehydratase activity was significantly larger in the high-phosphate group. This work demonstrates that excess dietary phosphate significantly increases lead toxicity and indicates the need for continued research on the interaction between dietary factors and lead toxicity.