Health surveillance of employees on a lead mine, 1979-1989.

Health surveillance of employees at a lead mine in the northern Cape, employing about 1,400 people, is specifically aimed at early detection of excessive lead absorption, which is the main chemical hazard. Over a period of 9 years the blood lead level distribution showed very few values (2.5%) that exceeded 60 micrograms/100 ml. The predictive validity (calculated according to the method of Alessio) of zinc protoporphyrin (ZPP) levels, at a cut-off level of 4 micrograms/g haemoglobin, to screen exposed workers in order to determine whether their blood lead level would exceed 50 micrograms/100 ml proved to be high (198). In 1988 a significant correlation between ZPP and blood lead levels was found in 195 employees at a low level of absorption manifested by an incidence of only 4% exceeding the cut-off level of 4 micrograms ZPP/g haemoglobin and only 2% exceeding a blood lead level of 50 micrograms/100 ml in that year. Monitoring by ZPP provides a high degree of safety for workers and is a relatively inexpensive, well-accepted and effective method.

Rehabilitation for employment. The Rehabilitation Centre of the Association for the Physically Disabled at Bridgetown, Athlone, CP.

Results of rehabilitation of physically disabled people for employment on the open labour market over the period 1975-1985 are presented. Out of 680 eligible clients, 53% were successfully placed. When corrected for uncontrollable withdrawals and uncontrollable dismissals the success rate rises to 77% (363 of 471 clients). The drop-out rate of 16% for preventable reasons and a partially preventable wastage of 31% are highlighted for potential action and improvement. The main reasons for admission were trauma (motor vehicle accidents, assaults and industrial injuries), poliomyelitis and congenital abnormalities in a ratio of 4:3:1. These groups accounted for 82% of all admissions. The problem of adequate evaluation and screening to predict outcome reliably is discussed and the use of a modified version of the International Classification of Impairments, Disabilities and Handicaps of the World Health Organisation is advocated. Of those clients who were successfully placed, 75-80% remained in employment for more than 1 year and 55-60% for more than 2 years. On the whole, the rehabilitation process appears to lead to successful re-integration into the working community for most of the physically disabled persons admitted to the Centre.

Rubella sensitivity in young women--an occupational hazard in hospitals.

This study of 1,496 serological results over a period of 4 years draws attention to the fact that there may be female personnel in the hospital setting who are not only at risk of contracting rubella but could also infect susceptible pregnant patients, and to the need for an effective programme of immunisation against rubella for hospital personnel. It was established that a higher proportion of young white female personnel (18% and more) than coloured personnel (4%) at Groote Schuur Hospital were susceptible to rubella, and that this figure was higher than in other South African centres and centres in many other countries.

Reliability of industrial audiometry as a screening method for incipient noise-induced hearing loss.

Pure-tone audiometry is at present regarded as the best available method in industry for the monitoring of noise-induced occupational hearing loss. The legal obligations and guidelines regarding this procedure are discussed in respect of the situation in the RSA and in other countries, and problems resulting from the time-growth curve for noise-induced hearing loss are emphasised. A survey of audiometric tests performed on 47 healthy men aged 20-41 years exposed to noise levels of 85-92 dB for at least 5 years is reported. The results of this survey reveal the limitations of audiometric monitoring. Some recommendations are made which would take account of these limitations and thus increase the reliability of audiometry in industry.

Biological monitoring of occupational exposure to lead with a zinc protoporphyrin (ZPP) meter.

Recent literature dealing with biological monitoring of people exposed to lead at work is reviewed. The widespread trend to regard lower levels of lead in air or in the blood of workers as acceptable or as recommended upper limits is discussed. Based on practical experience over a 6-month period, it is concluded that the zinc protoporphyrin (ZPP) test is an adequate, convenient and inexpensive screening method for monitoring workers exposed to lead in a motor care manufacturing plant.