High concentrations of heavy metals in neighborhoods near ore smelters in northern Mexico.
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In developing countries, rapid industrialization without environmental controls has resulted in heavy metal contamination of communities. We hypothesized that residential neighborhoods located near ore industries in three northern Mexican cities would be heavily polluted with multiple contaminants (arsenic, cadmium, and lead) and that these sites would be point sources for the heavy metals. To evaluate these hypotheses, we obtained samples of roadside surface dust from residential neighborhoods within 2 m of metal smelters [Torreon (n = 19)] and Chihuahua (n = 19)] and a metal refinery [Monterrey (n = 23)]. Heavy metal concentrations in dust were mapped with respect to distance from the industrial sites. Correlation between dust metal concentration and distance was estimated with least-squares regression using log-transformed data. Median dust arsenic, cadmium, and lead concentrations were 32, 10, and 277 microg/g, respectively, in Chihuahua; 42, 2, and 467 microg/g, respectively, in Monterrey, and 113, 112, and 2,448 microg/g, respectively, in Torreon. Dust concentrations of all heavy metals were significantly higher around the active smelter in Torreon, where more than 90% of samples exceeded Superfund cleanup goals. At all sites, dust concentrations were inversely related to distance from the industrial source, implicating these industries as the likely source of the contamination. We concluded that residential neighborhoods around metal smelting and refining sites in these three cities are contaminated by heavy metals at concentrations likely to pose a health threat to people living nearby. Evaluations of human exposure near these sites should be conducted. Because multiple heavy metal pollutants may exist near smelter sites, researchers should avoid attributing toxicity to one heavy metal unless others have been measured and shown not to coexist. (+info)
A health promotion programme for oil refinery employees: changes of health promotion needs observed at three years.
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The main aim of this three-year follow-up study was to evaluate the long-term effects of a workplace health promotion intervention programme offered by the Neste Oyj corporation's occupational health service. Another aim was to study factors associated with changes in health promotion needs. These were assessed using information obtained by means of questionnaires and laboratory measurements. The target areas assessed were physical activity, musculoskeletal problems, dietary habits, obesity, blood pressure, serum lipids, smoking, quality of sleep and mental well-being. Participants from one oil refinery were offered special health promotion counselling, while those from the other oil refinery studied received only their personal results, written information and instructions. Evaluation of the changes in needs was mainly based on comparison of the results of two examinations performed with an interval of three years. Effects of special health promotion counselling were observed in the target area of physical activity. Elimination of certain health promotion needs was seen in both groups in all of the target areas. The most extensive changes were seen in the target areas of musculoskeletal symptoms, dietary habits, blood pressure and mental well-being. Basic education, occupational status and age-group, as well as the value of tending health were frequent variables explaining the reduction in the need for health promotion activities. Worker participation in health promotion counselling activities provided by occupational health services can be high, as in this study in which the participation rate was 90% and the drop-out rate during the three years only 10%. (+info)
Ozone-induced respiratory illness during the repair of a portland cement kiln.
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OBJECTIVES: Workers at a portland cement plant had experienced acute respiratory and eye irritation when performing maintenance inside a kiln. These episodes were associated with a bleach-like odor, which was only reported during maintenance operations. An industrial hygiene investigation was conducted to determine the cause of the illness. METHODS: While workers replaced refractory brick inside the kiln, air samples were collected for chlorine, sulfur dioxide, inorganic acid, ozone, and dust. After the rebricking was completed and all the workers had exited the kiln, its electrostatic precipitator was reduced to half power and the induced-draft (ID) fan was turned off to recreate conditions present during illness episodes. RESULTS: Chlorine, inorganic acid, and ozone were not detected, and only trace concentrations of sulfur dioxide were detected while workers were inside the kiln. However, when conditions present during previous episodes were recreated, the bleach-like odor was soon evident. Chlorine was not detected, but 0.09 to 0.11 ppm of ozone was measured at the discharge end of the kiln, and 4.5 ppm was measured at the inlet end. Within a half hour after the electrostatic precipitator was turned off and the ID fan was turned on, the ozone concentrations decreased to background levels of 0.02-0.03 ppm. CONCLUSIONS: Somewhat lower ozone exposures may have occurred during previous kiln maintenance operations due to more open access portals, but previous episodes of eye and respiratory irritation were probably caused when ozone, generated by the electrostatic precipitator, back-drafted into the kiln after the ID fan was turned off. (+info)
Impact of shift work on cardiovascular functions in a 10-year follow-up study.
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OBJECTIVES: The purpose of this study was to determine whether shift work affects the heart-rate-adjusted QT interval (QTc) in electorcardiography (ECG) and the blood pressure of workers without overt cardiovascular dysfunction. METHODS: At a copper smelter, 158 shift workers and 75 day workers who underwent an ECG examination and blood pressure measurements in 1986 were followed for 10 years. In 1996, biochemical indicators such as high-density lipoprotein cholesterol and triglycerides were measured, together with the QTc. RESULTS: In 1986 and 1996, the QTc was significantly longer in the shift workers than in the day workers. Of 180 workers with a normal QTc (<420 ms(1/2) in 1986, 15% had developed a prolonged QTc (420 ms(1/2) in 1996 (18% of the 117 shift workers and 11% of the 63 day workers). Among the workers with a normal QTc in 1986, the shift workers had a significantly longer QTc than the day workers when the QTc was examined in 1996. In addition, shift-day work in the group with a normal QTc was significantly related to the QTc in 1996 after control for age, work duration, biochemical indicators, smoking, and drinking habits. However, the blood pressures of the shift and day workers did not differ significantly, and in 1996 the values of both groups were significantly elevated. CONCLUSIONS: These data suggest that shift work is associated with QTc prolongation. This evidence may explain the increased risk for cardiovascular diseases due to shift work. (+info)
Lymphohaematopoietic malignancy around all industrial complexes that include major oil refineries in Great Britain.
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OBJECTIVES: To examine the incidence of lymphohaematopoietic malignancy around industrial complexes that include major oil refineries in Great Britain after recent public and scientific concern of possible carcinogenic hazards of emissions from the petrochemical industry. METHODS: Small area study of the incidence of lymphohaematopoietic malignancies, 1974-91, within 7.5 km of all 11 oil refineries (grouped into seven sites) in Great Britain that were operational by the early 1970s and processed more than two million tonnes of crude oil in 1993. RESULTS: Combined analysis of data from all seven sites showed no significant (p < 0.05) increase in risk of these malignancies within 2 km or 7.5 km. Hodgkin's lymphoma, but no other malignancy, showed evidence (p = 0.02) of a decline in risk with distance from refineries, but there was an apparent deficit of cases of multiple myeloma near the refineries (p = 0.04). CONCLUSION: There was no evidence of association between residence near oil refineries and leukaemias, or non-Hodgkin's lymphoma. A weak positive association was found between risk of Hodgkin's disease and proximity to major petrochemical industry, and a negative association with multiple myeloma, which may be chance findings within the context of multiple statistical testing. (+info)
Update of a study of crude oil production workers 1946-94.
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OBJECTIVE: To update information on workers in the petroleum industry engaged in the production of crude oil to determine whether the patterns of mortality have changed with 14 additional years of follow up. METHODS: All workers were employed at company production and pipeline locations sometime during 1946-94. The cohort now consists of 24 124 employees with an average of 22 years of follow up. RESULTS: The overall mortality, and most cause specific mortalities were lower than or similar to those for the general United States population. For white men (81% of the cohort), there were 4361 observed deaths and 5945 expected, resulting in a significantly lower standardised mortality ratio (SMR) of 73. There were significant deficits for all the leading causes of death in the United States including all cancers, cancer of the lung, stroke, heart disease, respiratory disease, and accidents. Slightly increased mortality was found for cancer of the prostate, cancer of the brain and central nervous system, and cancer of other lymphatic tissue. For benign and unspecified neoplasms, the SMR was 152 (95% confidence interval (95% CI) 95 to 230). There was a significant increase for acute myelogenous leukaemia that was restricted to people who were first employed before 1940 and who were employed in production and pipeline jobs for >30 years. Overall mortality patterns for non-white men and women were similar to those for white men. Mortality patterns for white men were also examined by duration of employment, time first employed, and by job group. CONCLUSIONS: The results of the updated study showed a favourable mortality experience for crude oil production workers compared with the United States population. (+info)
Updated mortality among diverse operating segments of a petroleum company.
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OBJECTIVES: To update mortality for 34 560 employees from diverse operating segments of a Canadian petroleum company; and to investigate potential relations with occupational factors. METHODS: Employees from 1964-83 were linked to the Canadian mortality data base to provide 11 years additional follow up. There were 6760 deaths and 750 683 person-years of follow up compared with 3909 and 428 190, respectively, in the earlier study. Analyses used standardised mortality ratios (SMRs) to compare worker cause specific mortality with the Canadian general population. Duration of employment and latency analyses were performed for causes previously found to be increased in this and other petroleum cohorts, as well as any findings of interest. RESULTS: For the period 1964-94, employees experienced significantly low overall mortality (SMR=0.86 men, SMR=0.80 women). Kidney cancer, which has been increased in some studies of petroleum workers, was not increased. Acute non-lymphocytic leukaemia in exposed operating segments was consistent with the expected or only slightly, non-significantly increased. The most notable finding was increased deaths from mesothelioma among refinery and petrochemical workers (SMR 8.68; 95% confidence interval (95% CI) 5.51 to 13.03), most of whom were long term employees in jobs with presumed exposure to asbestos (mechanical and pipefitters). Deaths from multiple myeloma among marketing and distribution workers, which were previously increased, remained increased (SMR 2.08; 95% CI 0.95 to 3.95) in the update period 1984-94; however, there was no clear pattern by duration of employment or latency. Aortic aneurysms, which also were previously significantly increased among marketing and distribution workers approached the expected in the update period (SMR 1.18; 95% CI 0. 65-1.98). Analyses by duration of employment showed suggestive trends for aortic aneurysms, but earlier studies of this cohort have not found a relation between aortic aneurysms and exposure to hydrocarbons. CONCLUSION: The additional 2851 deaths and 322 493 person-years of follow up strengthened the assessment of mortality patterns relative to occupational factors. With the exception of mesothelioma, no clear work related increases in disease were identified. (+info)
Proximity to coke works and hospital admissions for respiratory and cardiovascular disease in England and Wales.
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BACKGROUND: The incidence of hospital admissions for respiratory and cardiovascular diseases in areas close to operating coke works in England and Wales was investigated. METHODS: A small area study using distance from source as a proxy for exposure was undertaken in subjects aged 65 or over and children under 5 years within 7.5 km of four coke works (1991 estimated populations 87 760 and 43 932, respectively). The main outcome measures were emergency hospital admissions in 1992/3-1994/5 with a primary diagnosis of coronary heart disease (ICD 410-414), stroke (ICD 431-438), all respiratory diseases (ICD 460-519), chronic obstructive pulmonary disease (ICD 491-492), and asthma (ICD 493) in those aged 65 or over, and all respiratory and asthma admissions in children under 5 years of age. RESULTS: At age 65 or over the combined estimate of relative risk with proximity to coke works (per km) ranged from 0.99 (95% CI 0.90 to 1.09) for chronic obstructive pulmonary disease to 1.03 (95% CI 0.94 to 1.13) for asthma. For children under 5 years the combined estimate of risk was 1.08 (95% CI 0.98 to 1.20) for all respiratory disease and 1.07 (95% CI 0.98 to 1.18) for asthma. There was evidence of significant heterogeneity in risk estimates between coke work groups, especially in children under 5 years (p<0.001 and p=0.004 for respiratory disease and asthma, respectively). For the Teesside coke works in North East England the relative risk with proximity (per km) was 1.09 (95% CI 1.06 to 1.12) for respiratory disease and 1.09 (95% CI 1.04 to 1.15) for asthma. CONCLUSIONS: No evidence overall was found for an association between hospital admissions and living near operational coke works in England and Wales. Trends of a higher risk of hospital admission for respiratory disease and asthma among children with proximity to the Teesside plant require further investigation. (+info)