Incompletely studied hazards of waste incineration

Airway function and respiratory symptoms in sanitation workers

The prevalence of acute and chronic respiratory symptoms and lung-function changes was studied in a group of 81 municipal sanitation workers. In addition, the prevalence of chronic respiratory symptoms and lung function was studied in 65 control workers. There were significantly higher prevalences of all chronic respiratory symptoms among the sanitation workers than among the control workers. Sanitation workers (smokers and nonsmokers) 40 years of age or older had higher prevalences of all chronic respiratory symptoms than younger workers. In addition, sanitation workers (both smokers and nonsmokers) employed for 10 years or longer had significantly higher prevalences of chronic respiratory symptoms than control workers. There was also a high prevalence of acute symptoms, which developed among the sanitation workers during work shifts. Of these symptoms, prevalences were highest for dryness of the nose and throat, followed by throat and eye irritation. Lung-function testing demonstrated significantly diminished forced vital capacity (FVC) and 1-second forced expiratory volume (FEV1) for the 81 sanitation workers compared with control values. These differences only become significant after 10 or more years of employment in the sanitation industry and were not entirely explained by smoking. These differences were smaller and not statistically significant for maximum flow rates at 50% and the last 25% of the vital capacity. Our data suggest that sanitation worker--particularly those with long periods of work exposure--may develop acute and/or chronic respiratory symptoms accompanied by decreases in lung function (primarily FVC and FEV1).

Respiratory function in sewage workers

Respiratory symptoms and ventilatory capacity were studied in a group of 74 sewage workers employed in cleaning the city sewage system of Zagreb, Croatia. Workers were studied by their work stations: closed channels (N = 26), drainage (N = 31), and other sewage workers (N = 17). The prevalence of chronic respiratory symptoms was higher in closed channel and drainage workers than in controls, particularly for chronic cough (range: 41.9-46.2% vs. 14.3%), chronic phlegm (range: 38.7-46.2% vs. 14.3%), chronic bronchitis (range: 32.3-42.3% vs. 8.6%), and chest tightness (range: 29.0-53.8% vs. 0%). In the first two groups of sewage workers there was a high prevalence of acute symptoms which developed during the work shift, being particularly pronounced for eye irritation (range: 16.1-26.9%), dyspnea (16.1-23.1%), dizziness (range: 6.5-23.1%), throat burning (9.7-19.2%), and skin irritation (range: 22.6-26.9%). Baseline ventilatory capacity was significantly decreased compared to predicted values in sewage workers; in particular, values for FEF50 and FEF25 were reduced, suggesting obstructive changes in smaller airways. Our data indicate that sewage workers experience frequent acute and chronic respiratory symptoms and exhibit objective evidence of respiratory dysfunction.

Morbidity among municipal waste incinerator workers

Incinerator workers are exposed to many toxic compounds, most notably heavy metals. We evaluated medical and exposure monitoring data of an actively employed cohort of Philadelphia incinerator workers following an Agency for Toxic Substances and Disease Registry site survey and National Institute for Occupational Safety and Health (NIOSH) health hazard evaluation (HHE). Of the many airborne samples taken by NIOSH, only four of the personal breathing zone samples were above OSHA or ACGIH standards: one for lead, one for phosphorous, and two for total particulates. Because samples were taken during limited operations (only one of the two incinerators were operating), the results may underestimate historical exposures at this site. We limited our medical analysis to the 86 male workers who participated in the HHE out of the 105 active employees. The 86 employees were divided into potential high and low exposure groups based on a work site analysis done by an independent industrial hygienist. Eight individuals had at least one elevated biological index indicating exposure to a heavy metal. These elevations, however, were unrelated to the workers' exposure categories. Furthermore, no clinically significant mean blood or serum measurements were noted. Thirty-four percent of the workers had evidence of hypertension which increased the risk of significant proteinuria. Neither hypertension nor proteinuria were related to exposure group. Changes in pulmonary function related only to smoking status. Although there was some evidence of an increased risk of exposure to products of incinerator waste, we could not relate the few elevated biological tests to exposure classification. Additional studies are needed to assess the potential health effects of municipal waste incinerator by-products.