Cancer mortality and morbidity among plutonium workers at the Sellafield plant of British Nuclear Fuels.
(9/5557)
The mortality of all 14 319 workers employed at the Sellafield plant of British Nuclear Fuels between 1947 and 1975 was studied up to the end of 1992, and cancer incidence was examined from 1971 to 1986, in relation to their exposures to plutonium and to external radiation. The cancer mortality rate was 5% lower than that of England and Wales and 3% less than that of Cumbria. The significant excesses of deaths from cancer of the pleura and thyroid found in an earlier study persist with further follow-up (14 observed, 4.0 expected for pleura; 6 observed, 2.2 expected for thyroid). All of the deaths from pleural cancer were among radiation workers. For neither site was there a significant association between the risk of the cancer and accumulated radiation dose. There were significant deficits of deaths from cancers of mouth and pharynx, liver and gall bladder, and larynx and leukaemia when compared with the national rates. Among all radiation workers, there was a significant positive association between accumulated external radiation dose and mortality from cancers of ill-defined and secondary sites (10-year lag, P = 0.04), leukaemia (no lag, P = 0.03; 2-year lag, P = 0.05), multiple myeloma (20-year lag, P = 0.02), all lymphatic and haematopoietic cancers (20-year lag, P= 0.03) and all causes of death combined (20-year lag, P= 0.008). Among plutonium workers, there were significant excesses of deaths from cancer of the breast (6 observed, 2.6 expected) and ill-defined and secondary cancers (29 observed, 20.1 expected). No significant positive trends were observed between the risk of deaths from cancers of any specific site, or all cancers combined, and cumulative plutonium and external radiation doses. For no cancer site was there a significant excess of cancer registrations compared with rates for England and Wales. Analysis of trends in cancer incidence showed significant increases in risk with cumulative plutonium plus external radiation doses for all lymphatic and haematopoietic neoplasms for 0-, 10- and 20-year lag periods. Taken as a whole, our findings do not suggest that workers at Sellafield who have been exposed to plutonium are at an overall significantly increased risk of cancer compared with other radiation workers. (+info)
Presence of Campylobacter and Salmonella in sand from bathing beaches.
(10/5557)
The purpose of this study was to determine the presence of thermophilic Campylobacter spp. and Salmonella spp. in sand from non-EEC standard and EEC standard designated beaches in different locations in the UK and to assess if potentially pathogenic strains were present. Campylobacter spp. were detected in 82/182 (45%) of sand samples and Salmonella spp. in 10/182 (6%). Campylobacter spp. were isolated from 46/92 (50%) of samples from non-EEC standard beaches and 36/90 (40%) from EEC standard beaches. The prevalence of Campylobacter spp. was greater in wet sand from both types of beaches but, surprisingly, more than 30% of samples from dry sand also contained these organisms. The major pathogenic species C. jejuni and C. coli were more prevalent in sand from non-EEC standard beaches. In contrast, C. lari and urease positive thermophilic campylobacters, which are associated with seagulls and other migratory birds, were more prevalent in sand from EEC standard beaches. Campylobacter isolates were further characterized by biotyping and serotyping, which confirmed that strains known to be of types associated with human infections were frequently found in sand on bathing beaches. (+info)
A double-selective tissue culture system for isolation of wild-type poliovirus from sewage applied in a long-term environmental surveillance.
(11/5557)
We describe a simple, cost-efficient, double-selective method for isolation of wild-type poliovirus from sewage samples containing vaccine polioviruses and other enteroviruses, with a detection limit of 18 to 50 PFU per 1 to 2 liters of sewage. By this method we were able to process 1,700 sewage samples collected between 1991 and 1996, from which 10,472 plaques were isolated, 41 of them being identified as wild-type polioviruses. (+info)
An investigation of factors contributing to styrene and styrene-7,8-oxide exposures in the reinforced-plastics industry.
(12/5557)
During the manufacturing of reinforced plastics, large amounts of styrene and trace quantities of styrene-7,8-oxide (SO) are released. Since previous work suggests that inhalation of even small amounts of SO might be an important health risk, we investigated several possible factors contributing to styrene and SO exposure during the manufacture of reinforced plastics. Factors related to job type, worker and the type and quantity of styrene-containing resins were investigated using mixed-effects multiple linear regression models. Overall, SO exposure levels were positively correlated with styrene exposure levels. However, this correlation was statistically significant only among hand laminators who had the highest exposures to both styrene and SO. An important factor for predicting both styrene and SO concentrations was the type of resin used, while the quantity of resin consumed was predictive of styrene but not of SO exposure. Since So exposure appears to be associated with factors other than coexposure to styrene, more effort should be placed on investigating emissions of SO per se. The type of mixed-models regression analysis employed in this study can be used for clarifying the underlying patterns for exposures to styrene and SO as well as for evaluating preventive measures. (+info)
Comparative personal exposures to organic dusts and endotoxin.
(13/5557)
The aims of the study were to provide valid comparative data for personal exposures to dust and endotoxins for different occupations and to calculate comparative data for the contamination of organic dusts with endotoxin. Nine different occupational settings were studied, drawn from the textile, agricultural and animal handling industries. Samples were collected by personal sampling techniques, using the Institute of Occupational Medicine (IOM) sampling head, glass fibre filters and rechargeable sampling pumps. The dust exposures were calculated by gravimetric analysis and using the calculated volume of air sampled were expressed as mg/m3. Endotoxin exposures were measured using a simple water extraction from the collected dusts, followed by a quantitative turbidimetric assay. Results were expressed as ng/m3, using the calculated volume of air sampled. In addition, the levels of the contamination of dusts with endotoxin for individual industries were expressed as ng/mg of collected dust. Two hundred and fifty-nine samples, collected from 9 different industries and across 36 different sites were analysed. This represented a sampling rate of 25% for the total work force. The average sampling time was 4.62 h. For all the dusts collected, a significant correlation between the collected dust and endotoxin was seen (r = 0.7 and p < 0.001). The highest dust exposures occurred during cleaning activities (grain handling: 72.5 mg/m3). The individuals exposed to the highest median level of dust and endotoxin were the animal handlers (poultry handlers, dust: 11.53 mg/m3, endotoxin: 71,995 ng/m3). Weaving and mushroom cultivation had the lowest exposures for dust and endotoxins. The mostly highly contaminated dusts (median values expressed as ng of endotoxin per mg of collected dust) were found in the animal handling (poultry: 1,030 ng/mg, swine: 152 ng/mg) and cotton spinning (522 ng/mg) industries. Processing of cotton and wool fibres was found to reduce the levels of contamination of dusts with endotoxin. In the study, valid comparative data for personal exposures to organic dusts and endotoxins have been presented. The highest exposures were found amongst animal handlers and during cleaning activities. The results highlight that dust exposures are greater in a number of industries than the set exposure standards. In addition, endotoxin exposures are found to be greater than levels at which harmful effects have been demonstrated. (+info)
Mineral fibre sampling and size selection.
(14/5557)
Potential health hazards due to fibre inhalation are only evaluated in a limited way by simple optical microscopy examination of the membrane filters on which the fibres have been collected. One must consider the amount of fibres deposited and persisting in the most vulnerable organ compartments. Exposure evaluated in this way must take account of the deposition efficiency and relative clearance efficiency of different regions of the respiratory tract, which depends mainly on the diameter and length distribution of the fibres. The fibre diameter roughly indicates the deposition site in the respiratory tract, while the length is mainly connected with toxicity. For these reasons, at international level, special samplers have been recently proposed, capable of distinguishing the fibre sizes, in order to separate the so-called 'thoracic fraction' (the total fibres which penetrate beyond the larynx) and the 'respirable fraction' (only the fibres reaching the non ciliated respiratory area), which represent the most interesting sizes as far as health effects are concerned. Our purpose in this context is to explore the feasibility of using the Inertial Spectrometer (INSPEC) as a sampler that separates the fibres according to their aerodynamic diameter. The optical and electron microscope observations of the samples demonstrate a satisfactory size separation of the fibres and alignment along the flow lines. Therefore, INSPEC is successful in restricting the microscopic analyses to the potentially noxious fibres and in assessing specific concentrations for each diameter interval. (+info)
Preliminary external quality assessment for the biological monitoring of carbon disulfide with urinary 2-thiothiazolidine-4-carboxylic acid.
(15/5557)
Four laboratories have participated in an external quality control assessment for the determination of 2-thiothiazolidine-4-carboxylic acid (TTCA). TTCA is used as a biomarker for exposure to CS2. Thirteen different urine samples were analyzed by each laboratory. Ten of these were spiked with known amounts of TTCA, and had either a high or intermediate creatinine content. Two samples without any TTCA were used as controls and one sample was a pool of samples of urine from five employees occupationally exposed to CS2. The latter had unknown TTCA content. For each sample, TTCA and creatinine concentration were determined. The samples were supplied in three consecutive deliveries. Several samples were offered more than once. Thus, within-laboratory variability could be established for creatinine and TTCA determination and accuracy could be determined for TTCA analysis. Within-laboratory variability was low for all laboratories for creatinine, although laboratory D seemed to have a slight downward bias. Accuracy for TTCA was good for all laboratories. No significant mean deviation from the expected TTCA value was encountered. There does not seem to be any clear influence of the TTCA concentration level of the samples on the accuracy and within-laboratory variability. Two of the four laboratories (A and C) showed lower within-laboratory variability than the other two for TTCA, although coefficients of variation between replicated samples are high for these two laboratories as well. The laboratory giving the best accuracy, gave the highest within-laboratory variability. A non-systematic, random error is probably the source of this. The results of this preliminary study indicate that analysis of TTCA, although regarded as an established biomarker, can give biases and thus negatively interfere with inferred dose-effect or dose-response relationships in occupational epidemiology. (+info)
Determination of hydroquinone in air by high performance liquid chromatography.
(16/5557)
A method for measuring hydroquinone in air was evaluated, both in the laboratory and in the workplace. The method involved sampling the inhalable fraction onto a filter contained in a multi-holed sampler with a back-up of Tenax TA, followed by desorption into acetonitrile and analysis by High Performance Liquid Chromatography. It was shown to be effective at measuring hydroquinone over the range 0.1 to 2 times a concentration of 0.5 mg/m3 for 8 h. (+info)