(33/1985) Risk of infection from heavily contaminated air.

In a factory processing shea nuts the dust concentrations were found to be up to 145 mg/m3 [80% respirable (1--5 micrometer)]. Bacterial examination of the dust revealed that under the worst conditions observed a worker might inhale 350,000 bacteria per 8 h. Of these, 3,000 were Ps. aeruginosa and 1,500 Salmonella spp. of nine different types. The possible health effects of these findings are discussed.  (+info)

(34/1985) Occupational exposure to lead--granulometric distribution of airborne lead in relation to risk assessment.

The amount of airborne lead absorbed by the body during occupational exposure depends not only on lead concentration in workplace air, but also on the granulometric distribution of the aerosol. The Occupational Safety and Health Administration (OSHA) set the lead Permissible Exposure Limit (PEL) at 50 micrograms/m3 on the basis of Bernard's model and a number of assumptions, including assumption "C", which predicts that the first 12.5 micrograms/m3 are made up of fine particles (aerodynamic diameter < 1 micron) whereas the remaining 12.5 micrograms/m3 consist of particles > 1 micron. Occupational exposure to airborne lead at a concentration of 50 micrograms/m3 and a granulometric distribution calculated according to the above mentioned assumption, leads, in the model, to a mean blood level of 40 micrograms/dl. In the present study, we tested the validity of assumption "C" in the environmental air of a factory that manufactured crystal glassware containing 24% lead oxide. An 8-stage impactor was used to measure the particle size of airborne dust collected from personal and area samplings. Results indicate that, on the whole, assumption "C" cannot be considered valid in the work environment investigated in this study. As a result, lead absorption levels in exposed workers may be noticeably different from those predicted by the OSHA model. We therefore suggest that in order to make a correct evaluation of the risk of occupational exposure to lead, it is essential to integrate total airborne lead concentration with a measurement of the granulometric distribution of the aerosol.  (+info)

(35/1985) Environmental measurements of total dust and fiber concentration in manufacturer and user of man-made mineral fibers.

Man-made mineral fibers (MMMF), most of which are referred to as man-made vitreous fibers (MMVF), are mostly amorphous silicates manufactured from glass, rock, or other minerals. Analysis for MMMF have been restricted largely to the measurement of total airborne mass concentrations, but more recently to the determination of airborne fiber levels by phase contrast optical microscopy. In Korea, many small factories are related with manufacturing and using MMMF without any special evaluation of environmental measurements. Though MMMF are known as the substitute of asbestos and their toxicity are regarded as very low, MMMF do not totally excluded from the respiratory and/or skin diseases now. Therefore, we evaluated the environments of many workplaces with total dust and fiber concentration. Most dust and fiber concentrations were below threshold limit value (TLV) at various industries and working processes. However, these data showed a slight relationship between total dust and fiber concentration.  (+info)

(36/1985) Risks of respiratory disease in the heavy clay industry.

OBJECTIVES: Little information is available on the quantitative risks of respiratory disease from quartz in airborne dust in the heavy clay industry. Available evidence suggested that these risks might be low, possibly because of the presence in the dust of other minerals, such as illite and kaolinite, which may reduce the harmful effects of quartz. The aims of the present cross sectional study were to determine among workers in the industry (a) their current and cumulative exposures to respirable mixed dust and quartz; (b) the frequencies of chest radiographic abnormalities and respiratory symptoms; (c) the relations between cumulative exposure to respirable dust and quartz, and risks of radiographic abnormality and respiratory symptoms. METHODS: Factories were chosen where the type of process had changed as little as possible during recent decades. 18 were selected in England and Scotland, ranging in size from 35 to 582 employees, representing all the main types of raw material, end product, kilns, and processes in the manufacture of bricks, pipes, and tiles but excluding refractory products. Weights of respirable dust and quartz in more than 1400 personal dust samples, and site histories, were used to derive occupational groups characterised by their levels of exposure to dust and quartz. Full size chest radiographs, respiratory symptoms, smoking, and occupational history questionnaires were administered to current workers at each factory. Exposure-response relations were examined for radiographic abnormalities (dust and quartz) and respiratory symptoms (dust only). RESULTS: Respirable dust and quartz concentrations ranged from means of 0.4 and 0.04 mg.m-3 for non-process workers to 10.0 and 0.62 mg.m-3 for kiln demolition workers respectively. Although 97% of all quartz concentrations were below the maximum exposure limit of 0.4 mg.m-3, 10% were greater than this among the groups of workers exposed to most dust. Cumulative exposure calculations for dust and quartz took account of changes of occupational group, factory, and kiln type at study and non-study sites. Because of the importance of changes of kiln type additional weighting factors were applied to concentrations of dust and quartz during previous employment at factories that used certain types of kiln. 85% (1934 employees) of the identified workforce attended the medical surveys. The frequency of small opacities in the chest radiograph, category > or = 1/0, was 1.4% (median reading) and seven of these 25 men had category > or = 2/1. Chronic bronchitis was reported by 14.2% of the workforce and breathlessness, when walking with someone of their own age, by 4.4%. Risks of having category > or = 0/1 small opacities differed by site and were also influenced by age, smoking, and lifetime cumulative exposure to respirable dust and quartz. Although exposures to dust and to quartz were highly correlated, the evidence suggested that radiological abnormality was associated with quartz rather than dust. A doubling of cumulative quartz exposure increased the risk of having category > or = 0/1 by a factor of 1.33. Both chronic bronchitis and breathlessness were significantly related to dust exposure. CONCLUSIONS: Although most quartz concentrations at the time of this study were currently below regulatory limits in the heavy clay industry, high exposures regularly occurred in specific processes and occasionally among most occupational groups. However, there are small risks of pneumoconiosis and respiratory symptoms in the industry, although frequency of pneumoconiosis is low in comparison to other quartz exposed workers.  (+info)

(37/1985) Exposure-response relations of alpha-amylase sensitisation in British bakeries and flour mills.

OBJECTIVES: To describe the levels of exposure to fungal alpha-amylase in British bakeries and flour mills, and to describe the relation between exposure to alpha-amylase and sensitisation to fungal alpha-amylase. METHODS: 495 personal flour dust samples were taken in seven British bakeries and flour mills and analysed for alpha-amylase with an immunoassay. Workers at the sites were asked to fill out questionnaires on work related symptoms, smoking history, and work history, and they were skin prick tested with common allergens and fungal alpha-amylase to assess sensitisation. RESULTS: Exposure to high concentrations of alpha-amylase occur in a few areas of British bakeries and flour mills, and there can be considerable differences in exposures to alpha-amylase between sites and between exposure groups, and even within similar exposure groups from different sites. Exposure to the highest concentrations of alpha-amylase was found in the dispensing and mixing areas of the bakeries (geometric mean (GM) 39.7 ng/m3). Exposure to alpha-amylase showed only a moderate correlation with concentrations of dust (r = 0.42) and flour aeroallergen (r = 0.46). The results also showed a relation between exposure to alpha-amylase and sensitisation to fungal alpha-amylase (prevalence ratio (PR) for medium exposure 3.9, 95% confidence interval (95% CI) 0.8 to 20.2, PR for high exposure 9.9, 95% CI 2.8 to 34.6) compared with the low exposure category). Atopic subjects had an increased risk of sensitisation, but this was not significant. CONCLUSION: This study suggests that exposure to alpha-amylase is a considerable health risk in British bakeries and flour mills. A small proportion of workers are exposed to alpha-amylase at concentrations that result in high rates of sensitisation. A reduction in exposure to alpha-amylase is likely to reduce this risk.  (+info)

(38/1985) Health surveillance in milling, baking and other food manufacturing operations--five years' experience.

The objective of this study was to describe the incidence of allergic respiratory disease and its outcome in terms of symptoms and jobs, across different flour-using industries. It uses the findings of a health surveillance programme in a large food organization over a five-year period. The population under surveillance consisted of 3,450 employees with exposure to ingredient dusts, of whom 400 were in flour milling, 1,650 in bread baking, 550 in cake baking and 850 in other flour-using operations. A total of 66 employees with either asthma or rhinitis symptoms attributable to sensitization to allergens in the workplace were identified. The majority of these (48/66) had become symptomatic prior to the commencement of the health surveillance programme in 1993. The incidence rates (per million employees per year) for those who developed symptoms between 1993 and 1997 were 550 for flour milling, 1,940 for bread baking, 0 for cake baking and 235 for other flour-using operations. The agent believed to be responsible for symptoms was most commonly grain dust in flour millers and fungal amylase in bread bakers. Wheat flour appeared to have a weaker sensitizing potential than these other two substances. In terms of outcome, at follow-up 18% of symptomatically sensitized employees had left the company. Two of the ex-employees retired through ill health due to occupational asthma. Of those still in employment, 63% described an improvement in symptoms, 32% were unchanged and 4% were worse than when first diagnosed. Over half the cases still in employment were continuing to work in the same job as at the time of diagnosis.  (+info)

(39/1985) Systemic sclerosis (scleroderma) in two iron ore mines.

Six males with systemic sclerosis were observed in the work forces of two iron ore mines. The usual spectrum of clinical features encountered in systemic sclerosis patients were present. Histologic examination of pulmonary tissue was performed on three of the cases and showed features of both silicosis and scleroderma but to different degrees and stages of development. Exposure to high levels of silica-containing dusts had occurred in all six cases.  (+info)

(40/1985) Distribution of pesticides and polycyclic aromatic hydrocarbons in house dust as a function of particle size.

House dust is a repository for environmental pollutants that may accumulate indoors from both internal and external sources over long periods of time. Dust and tracked-in soil accumulate most efficiently in carpets, and the pollutants associated with dust and soil may present an exposure risk to infants and toddlers, who spend significant portions of their time in contact with or in close proximity to the floor and who engage in frequent mouthing activities. The availability of carpet dust for exposure by transfer to the skin or by suspension into the air depends on particle size. In this study, a large sample of residential house dust was obtained from a commercial cleaning service whose clients were homeowners residing in the Raleigh-Durham-Chapel Hill (Research Triangle) area of North Carolina. The composite dust was separated into seven size fractions ranging from < 4 to 500 microm in diameter, and each fraction was analyzed for 28 pesticides and 10 polycyclic aromatic hydrocarbons (PAHs). Over 20% of the fractionated dust sample consisted of particles < 25 microm in diameter. Fourteen pesticides and all 10 of the target PAHs were detected in one or more of the seven size-fractionated samples. Sample concentrations reported range from 0.02 to 22 microg/g; the synthetic pyrethroids cis- and trans-permethrin were the most abundant pesticide residue. The concentrations of nearly all of the target analytes increased gradually with decreasing particle size for the larger particles, then increased dramatically for the two smallest particle sizes (4-25 microm and < 4 microm).  (+info)