Blood lead levels in children in Perth, Western Australia.

This study reports on an analysis of the lead concentrations in 123 venous blood samples collected from Perth children aged between two months and 17 years attending Princess Margaret Hospital. The overall geometric mean was 6.9 micrograms lead per 100 ml whole blood, with 95 per cent of results lying between 3.2 and 14.8 micrograms/100 ml. Among children under five years of age, those aged between 18 months and two years had the highest geometric mean blood lead (11.1 micrograms/100 ml). There were no consistent associations between geometric mean blood lead and area of residence, age group or sex. In this sample of Perth children, the mean blood lead concentration was lower than those reported in other studies. Less than 0.1 per cent of children of the age ranged studied would have been expected to have lead levels exceeding the NHMRC 'level of concern' (25 micrograms/100 ml) current at the time of the study. However, the recent adoption of goal of less than 10 micrograms/100 ml could mean that lead levels in up to 21 per cent of Perth children would now be regarded as excessive.

Organochlorine pesticides in Western Australian nursing mothers.

OBJECTIVES: To measure the concentrations of organochlorine (OC) pesticides in nursing mothers in Western Australia and to evaluate the safety of these concentrations for breast-fed infants; to evaluate the need for future monitoring of OC pesticide concentrations and to determine whether breast milk is an accurate substitute for adipose tissue in future monitoring programs. DESIGN: Two cohorts of nursing mothers were recruited during the period October 1990 to March 1991. Levels of OC pesticides were measured in 128 samples of breast milk and 31 samples each of adipose tissue, maternal blood and cord blood. Laboratory analysis was by gas chromatography with electron capture. Health Department studies since 1974 were collated and levels of OC pesticides compared over time. RESULTS: DDT (dichlorodiphenyltrichloroethane), HCB (hexachlorobenzene) and dieldrin were found in all samples of breast milk and adipose tissue. A significant fall in the levels of OCs was noted since the 1974 survey, with the current concentrations of the cyclodienes (heptachlor, chlordane and dieldrin) being close to the limit of detection of the assay. The acceptable daily intake for dieldrin was exceeded in 90% of infants and for heptachlor in 2% of infants. The daily intakes of the other OCs were below the respective acceptable levels. HCB was detected at a median level of 0.1 mg/kg in both breast milk and adipose tissue despite being deregistered in 1972. As there is no current acceptable daily intake for HCB, the safety of this level could not be assessed by this method. A low correlation was found between levels of the cyclodiene pesticides in breast milk and adipose tissue, but levels of DDT and HCB were closely correlated. CONCLUSIONS: Restrictions on the use of the OC insecticides (DDT, aldrin, dieldrin, heptachlor and chlordane) have resulted in reduced concentrations of these chemicals in breast milk and adipose tissue as compared with previous studies. The dieldrin intake of breast-fed infants consistently exceeded the acceptable daily intake; the heptachlor intake exceeded the acceptable daily intake in some infants, but the low concentrations of heptachlor in breast milk made accurate measurement difficult. The concentrations of DDT and chlordane in breast milk did not pose a hazard to breast-fed infants. The significance of the levels of the fungicide HCB in breast milk cannot be determined. The widespread distribution of HCB, its marked persistence in the environment and its potential for human toxicity indicate a need for continued monitoring, for which breast milk is a suitable medium. The poor correlation between concentrations of dieldrin, heptachlor and chlordane in breast milk and adipose tissue may reflect the technical difficulty of measuring chemical concentrations close to the limit of detection. As aldrin is a registered pesticide and the dieldrin intake of breast-fed infants is consistently above the acceptable daily intake, monitoring of dieldrin should continue. Further population monitoring of DDT, heptachlor and chlordane is unlikely to be of value.

Variation in hospital morbidity in the male workforce of Western Australia.

The associations of hospital morbidity with occupation were studied in Western Australian men of working age in 1981-2. Data on hospital morbidity were derived from a population based system that covered all short stays in hospitals in the state. Occupations were grouped into 12 major categories and conditions were coded using the International Classification of Diseases. Armed services personnel had the highest overall rate of hospital admissions, followed by transport and communications workers and by administrative and managerial workers. Injuries were the most common cause of referral to hospital. Four occupational groups, farmers and allied workers, miners and quarrymen, transport and communications workers, and craftsmen, production workers, and labourers were often associated with injury. Diseases of the musculoskeletal system and connective tissue were the second most common cause for referral and were increased in transport and communications workers, and in craftsmen, production workers, and labourers. Several other associations between causes of hospital admission and major occupational groups were observed, including associations of circulatory system diseases with professional and technical work and with administrative and managerial work. The excess of hospital admissions due to factors associated with occupation was estimated to be 12,665 admissions a year or 24.9% of the total in working men.

Determinants of chronic bronchitis and lung dysfunction in Western Australian gold miners.

The relation of chronic bronchitis and respiratory dysfunction to age, tobacco smoking, and occupational exposure to surface and underground mining operations were examined in a cross sectional survey of 1363 men employed in the Kalgoorlie mining industry in 1985. Overall, the prevalence of chronic bronchitis was 14%. Eleven per cent of the workers had obstructive lung disorder (FEV1/FVC less than 0.70) and 9% had restrictive lung disorder (FVC less than 0.80 of predicted for height and age). There was little change in the prevalence of chronic bronchitis from that observed in a survey of the same industry in 1961-2. Only 1% of the workers in 1985 had radiographic signs of silicosis compared with 22% in 1961-2. Age, smoking, and underground mining experience all exerted strong effects on the development of chronic bronchitis with or without associated respiratory function abnormalities. After control of confounding by age and smoking, it was estimated that compared with a lifetime non-miner, the odds ratio (OR) of chronic bronchitis was 1.8 (95% confidence interval, 1.0-3.3) for one to nine years underground mining gold, 2.5 (1.2-5.2) for 10-19 years, and 5.1 (2.4-10.9) for 20 or more years. Underground mining of minerals other than gold was also associated with chronic bronchitis (OR = 5.1; 95% CI, 1.1-25.0) whereas exclusive surface mining had only a small empirical effect (OR = 1.3; 95% CI, 0.6-2.5). It is estimated that the proportion of cases of chronic bronchitis in working underground miners due to occupational factors is 50%. The results support the existence of an industrial cause of chronic bronchitis, although caution must be exercised in generalising the results to miners with progressive and sever respiratory impairment.