Respiratory effects from work-related exposure to welding fumes in Hamadan, Iran

INDUSTRIAL WELDING has been associated historically with lung diseases, and popular welding techniques continue to bring into view many potential exposures to particulates and gases. (1) The welding proces bring outs a complex mixture of irritant gases, coarse metal particulates, and fine metal oxide smoke (2) The correct manual welding technique requires the welder to remark the arc directly from a distance of 18 inches. There is a potential risk for inhalation of the feather both by welders and by the agency of others working nearby with inadequate respiratory protection. Therefore, welding may involve inhalation in all senses to a number of effluvium components, depending on the metal or specific welding processe used. (3-5) Concentrations of airborne effluviums depend on working circumstances, like as welding technique, welding position, air ventilation combination of parts to form a whole and use of respiratory protective devices. (67)

Researchers in several previous studies (12) have set higher prevalence of chronic bronchitis among welders; however, this association was not seen in all studies, (23) and there is potential for confounding from other relevant exposing s such as cigarette smoking, previous occupational exposing s and air pollution. A comprehensive contemplate of British welders was reported through Doing and Duguid in 1951 (8) on the contrary the health of these workers has not been studied extensively since then. (5) Moreover, respiratory illnesses among welders appear to be the rise of the interaction between welding vapor inhalation and cigarette smoking. (17)

It is clear that a certain number of outdoor air pollutants can cause respiratory disease just as gases or particulates do. Thus, these can be sources of bias for application of mind Also, most investigations of metal effluvium and its respiratory effects are carried without in developed countries. Our aim in this inquiry was to assess the influence of arc carbonized iron welding on the respiratory health and lung function of unprotect workers in a city with depressed proportions of air pollutants, while taking smoking habits into account. We also determined the composition of a certain quantity of metal fumes.

Method

application of mind population. The exposed group comprised 63 full-time manual carbonized iron arc welders employed in welding workshops in Hamadan, Iran. All subdues worked as welders and were likely to be expos to mixes of metal steams and gases (NO, N[O.sub.2], ozone) as well as other particulates. The rule group, selected from outside the workshops, had no in every one's mouth or previous welding exposure or occupational exposing to silica, asbestos, or solvents; their demographic characteristics were similar to those of the expos assemblage They were examined by spirometry and questionnaire interview during 2002

Questionnaire. The close attention questionnaire included items on demographics, smoking habits, job-related respiratory symptoms, and duration of piece of work experience. The questionnaire on respiratory symptoms was a version of the Medical Research Council questionnaire, modified by the agency of the British Occupational Hygiene Society, (910) translated into Persian and previously validated. We defined chronic bronchitis as regular mucus production at any time of the day for at least 2 yr and a minimum 3 mo of the year. We defined job-related respiratory symptoms as cough wheeze, chest tightness, and shortness of breath that became worse at work or improved during days not upon from work.

Pulmonary function. We asked 63 expos workers, and 78 unexpos proffers as a control group, to perform pulmonary function trials with a calibrated vitalograph spirometer. We measured vital capacity (VC) forced vital capacity (FVC) forced expiratory whirl in 1 sec (FE[V.sub.1]), and 25-75% forced expiratory pour (FE[F.sub.25-75%]) with subjects in the standing position.

Metal reek monitoring. We collected metal steam samples from the respiratory girth inside the welding mask of a worker, upon mixed cellulose ester filters (08 lam pore size), and analyzed them through atomic absorption spectroscopy (11,12) (Thermao Gerrell Ash, design SH22).

Statistical analysis. We used SPS software (SPS Inc., Chicago, IL) for all statistical analysis. We compared the assembleed data and estimated it between sum of two units groups or a group and standard value by means of the mean and standard deviation (SD) and associated t ordeal and [chi square] test.

Results

Table 1 exhibits the means of metal vapor concentrations in the respiratory baldric of welders, inside the welding mask. Iron effluvium had the highest concentration (311 mg/[msup3]) more than six times the doorsill limit value (TLV[R]) recommended by the agency of the American Conference of Governmental Industrial Hygienists (ACGIH), (13) and chromium had the lowest concentration. None of the welders used a personal safety mask at the time of this investigation, on the contrary most of the workshops had at least a fan for general ventilation. Demographic details and the number of smoker in the cohort are shown in Table 2 The 63 welders did not differ significantly from the 78 nonwelder tenders in terms of age and height (p > 0788 and p > 0151 respectively) on the contrary differed significantly in terms of weight and years of experience upon the job (p < 0001) The mean of total in all senses was 13.76 yr for welders. Thirty percent of welders used cigarettes, compared with 23% of nonwelders. Table 3 displays the prevalence of asthma and clinical symptoms among welders and nonwelders at the time of investigation and indicates their smoking habits. The ensues showed that 52.38% of welders and 2692% of nonwelders complained of cough Prevalence of cough was higher for smoker than nonsmokers. Four welders and individual nonwelder reported asthma. Chronic bronchitis was more for the use of all among welders (1 7.45%) than among nonwelders (376%) and the difference was significant (p < 0001) Other work-related symptoms, including production of mucus wheezing, shortness of breath, and nasal allergies, were more repeatedly reported by welders (50.79, 111 4817 and 1903% respectively) than through nonwelders (23.07, 2.56, 26.92, and 762% respectively). The differences between welders and nonwelders were statistically significant in limits of phlegm production, wheezing, shortness of breath, and nasal allergies (p < 0001 p < 0039 p < 0001 and p < 0045 respectively).