Arcangeli, Giulio

Baldasseroni, Alberto

Cupelli, V.

Giuliano, Giovanni

Montalti, M.

Pristera, M.

English

Florence Research

INTERNATIONAL JOURNAL OF IMMUNOPATHOLOGY AND PHARMACOLOGY Vol. 17, no. 2 (S), 91·96 (2004)RESPIRATORY RISKS IN TUNNEL CONSTRUCTION WORKERSG. ARCANGELI, V. CUPELLI, M. MONTALTI, M. PRISTERA',A. BALDASSERONI* and G. GIULIANODipartimento di Scienze Ortopediche, Ricostruttive e del Lavoro - Universita di Firenze'Azienda Sanitaria di Firenze Largo P. Palagi 1 - eTO - 50139 Firenze, ItalyRespiratory diseases are frequent in tunnel construction workers. A group of 144 subjects randomlyselected from the population of 2516 workers engaged in the construction of the railway tunnel under theAppennine Mountains, from Bologna to Firenze was investigated. A group of 69 males comparable for age,living area and habits was studied as a control group. Assessment of air pollutants (NO, NOz'SOz' total dust,silica %) was carried out by means offixed monitoring stations as well as personal monitors. All the subjectsincluded in the study were examined with a standardised protocol which included physical examination,lung function tests (before and after shift work) and a questionnaire to collect respiratory symptoms. Lowconcentrations of environmental pollutants were evidenced. Significantly lower values of FEV) and PEFwere determined in the worker group pared to controls. A significant decrease in respiratory parameterswas shown after shift work. Variables capable of influencing the decrease in parameters include smokinghabits, work activity, presence of cough and expectoration, period of the year (spirometries resulted worsein the winter time). Significantly lower values of FEV) and PEF were evidenced in the workers comparedto controls. In spite of the present low work environmental exposure conditions, some physiologicparameters appear altered in tunnel construction workers. This may depend on a variety of noxious agentspresent in the working environment.Tunnel construction work is related torespiratory disease risks due to a variety ofexposures, including total and silica dust, dieselexhaust fumes, and nitrogen dioxide (1). Dust isgenerated by rock blasting and drilling and duringtransport operations; a-quartz concentrationdepends on the geology at the work site. Diesel-powered machines, used in tunnel constructions,produce nitrogen dioxide and carbon monoxide(2). An increased risk of obstructive pulmonarydisease (3) and acute shift work reduction in somefunctional respiratory parameters have been reportedin tunnel construction workers (4). Decreasedlung function and bronchial hyperresponsivenessare described in subjects daily exposed to nitrogendioxide (5).The use of environmental and personnelprotection devices allows to highly reduce theworkers' exposure to dust and gases. The aim ofthis study was to evaluate the actual occurrence ofrespiratory symptoms and airflow limitation intunnel construction workers, in particular byevaluating the acute shift work respiratory response.MATERIALS AND METHODSThe study was conducted in the area of theAppennine Mountains, where a new railway line fromBologna to Firenze, with total of 72.4 Km of tunnelunder the earth's surface, is under construction. Weinvestigated the two major tunnels under construction,named the "Rovigo" tunnel and the "Carlone" tunnel.The underground construction includes exavation, rocksupport, finishing works such as the installation ofelectricity and road paving. The method of drilling andblasting was, and is.used. Fumes are ventilated throughthe tunnel cavity using a one-way ventilation system(2).Key words: lung function; occupational respiratory disease, tunnelMailing address: Dr. Giulio ArcangeliDipartimento diScienze Ortopediche, Ricostruttive e del Lavoro,Universita diFirenzeLargo P.Palagi I - eTO- 50139 Firenze, ItalyTel. 0039 055 4278259Fax 0039 055 4278130e-mail: arcangelig@ao-careggi.toscana.it910394-6320 (2004)Copyright © by BIOLIFE. s.a.s..This publication and/orarticleis for individual usconlyand maynot he furtherreproduced withoutwriucnpermission from thecopyright holder.Unauthorized reproduction mayresult in financial andother penalties92 G. ARCANGELI ET AL.Environmental monitoringAssessment of air environmental pollutants (totaldust and silica %, NO, NOz' SOz) was carried out usingfixed monitoring stations. Personnel monitors duringthe shift work were also used for gaseous pollutants.Total dusts were collected on acrylic copolymer mem-brane filters and the particle mass was then measuredwith a microbalance. The a-quartz content was measuredusing the NIOSH Method 7500 (6). Concentrations ofNO, NOz' SOz were measured with direct-readingelectrochemical sensors.PopulationA group of 176 male subjects was randomly selectedfrom the total population of 2516 workers engaged inthe construction of the railway tunnel. A group of 144subjects (81.9%) agreed to participate in the study. Ascontrols, we studied a group of 69 males comparablefor age, living area and habits.The demography of the groups is reported in tab.I. The distribution for job categories included: Drivers:39 subjects (27%), Machine operators: 39 (27%),Carpenters: 36 (25%), Miners: 17 (12%), Electricians/Assistants: 13 (9%).Smoking habit did not significantly differ betweenthe workers in the two tunnels, or between groups ofdifferent job categories.All the subjects included in the study were examinedas follows:1.The CECA questionnaire was used to collectrespiratory symptoms2.Medical examination3. Spirometric measurements (before and after shift-work) were performed in the sitting position (MasterScreen Pneumo, Jaeger, Germany), operated by thesame trained physician, in accordance with ATSguidelines (7).In a group of twenty workers, a serial measurementof peak expiratory flow along a period of two weekswas performed. Obtained data were analysed using aspecific computerized programme.Statistical methodsThe descriptive statistics of data were performedwith the SPSS package. To assess the influence ofdifferent covariates on the results in terms of flow-volume curves, we tested a linear regression model,using as independent variables the different parametersofthe curve (FVC, FEVI, FEF25, FEF50, FEF75, PEF)as a percentage of theoretical values, based on age,height and weight. However, the data set includedmeasurements which were not independent.Repeated sampling data from the same subjectwere correlated and they were not independentobservations as needed in a common statistical analysis.As a consequence, the estimate variance is biased,resulting in too narrow a confidence interval. To copewith this problem we used a statistical technique, applyingthe GEE (Generalized Estimating Equation) to thegeneral linear regression, by means of STATA xtgeecommand. Among the different approaches to managethe problem of autocorrelation, the GEE approach hasthe property ofrobustness against the choice of variance-covariance matrix, that is, the structure of autocorrelation.In fact, we chose the default matrix, the so called"exchangeable matrix", where rs in the different repeatedmeasurements were considered the same.The linear regression model was selected as theresult of a backward exclusion of covariate with at-testfor the partial coefficient above 10% of probability.However, in the tables all tested models are shown. Foreach partial coefficient, the 95% confidence limits areshown. As referred to the percentage ofexpected valueson the basis of theoretical equation, the partial regressioncoefficients can be read directly as a percentage due tothat covariate. The tables show only the most informa-tive equations among those tested, i.e. that of FEVI %and that of PEF% as independent variables.RESULTSThe environmental monitoring (fixedmonitoring) for total dust.showed that 7% of thesamples was higher than the TL V-TWA level,21 % was higher than 50% of the TLV-TWA level,and the remaining 72%, lower than the 50%.Moreover, in 19% of monitoring silica exceededthe TL V-TWA level. Total dust mean value in the"Rovigo" tunnel was 2.71 mg/rrr', whereas it was1.64 mg/ m' in the "Carlone" tunnel. No significantdifferences were found for silica concentrations.Significant higher values of environmental NOwere found in the "Rovigo" tunnel (6.2 ppm vs.3.4). On the other hand, slightly higher values ofNOz' CO and COz were found in the "Carlone"tunnel. In personal monitoring, NO, N02 wereundetectable in respectively the 13.6% and 34.9%of the samples, showing low concentrations in anycase. Data, for job categories, are presented inFig.l.Int. J. Immunopathol. Pharmacal.Years Smoking statusAge working in Former CurrentJob group tunnelsmokers Non smokers smokersMean SD Mean SD Mean % Mean % Mean %Total no. of 40,1 10,1 12,3 10,1 34 24 40 28 60 49workers (144)The "Rovigo" 41,8 10,1 12,4 9,2 29 26 32 29 51 46tunnel (112)The "Carlone" 44,1 8,6 12,1 12,3 5 16 8 25 19 59Tunnel (32)Controls (69) 34,7 9,7 14 20 27 39 28 41Tab. I. Characteristics of the study populationJob Group Smoking Habits FVC% PEF% FEV. % FEV./VC %Non smokers 107.1 ±9.6 105.2 ± 19.10 109.8 ± 9.6 102.7 ± 7.6Current smokers 110.8 ± 9.8 104.9 ± 14.2 108.9 ± 12.2 100.8 ± 8.0ControlsFormer smokers 103.8 ± 15.4 105.3 ± 23.3 104.3 ± 17.0 101.4 ± 7.6Total 107.8 ± 11.3 105.1 ± 18.3 108.3 ± 12.5 101.7 ± 7.7Non smokers 105.7 ± 12.0 104.2 ± 17.6 105.3 ± 13.2 103.1 ± 9.0Total Current smokers 104.5 ± 12.1 92.6 ± 14.5 99.9 ± 12.0 98.3 ± 7.5Workers Former smokers 108.9 ± 11.8 99.0 ± 12.3 108,.4 ± 12.9 102.8 ± 7.9Total 105.9 ± 12.1 97.1 ± 19.0 103.3 ± 13.1 100.6 ± 8.3Non smokers 103.6 ± 11.4 102.2 ± 19.7 103.9 ± 14.11 103.8 ± 9.8The Current smokers 102.5 ± 12.1 91.4 ± 19.2 97,.5 ± 12.6 97.9 ± 7.7"Rovigo"Workers Former smokers 108.3 ± 11.9 99.4 ± 16.5 108.1 ± 13.1 103.0 ± 8.4Total 104.3 ± 12.0 96.3 ± 19.2 101.9 ± 13.8 100.8 ± 8.9Non smokers 113.9 ± 14.3 112.0 ± 9.0 110.9 ± 9.8 100.2 ± 6.0The Current smokers 109.9 ± 12.0 95.9 ± 20.7 106.4 ± 10.5 99.43 ± 7.0"Carlone"Workers Former smokers 112.1 ± 11.1 96.4 ± 8.1 109.9 ± 11.6 101.7 ± 4.7Total 111.3 ± 12.4 100.0 ± 18.1 108.1 ± 10.5 100.0 ± 6.4Tab. II. Lung function in study population (% of predicted values).Values are expressed as mean ± SD9394 G. ARCANGELI ET AL.FEVt 0/0 PEF% Tab. III. LinearVariance Varianceregression analysis data.coefficient P>lzl coefficient P>lzlCurrent smokers -5.10 0.021 -9.93 0.001Former smokers 0.06 0.983· -2.17 0.545Test after shift--1.03 0.120 -3.01 0.007workTest in winter time -3.24 0.001 -7.93 0.000The "Carfone" 1.53 0.581 -1.64 0.671tunnelThe ··Rovigo"-3.89 0.063 -5.80 0.048tunnel65(J)0..:::s 4e0~(]) 3-c0~2IIIIII_N021o NOFig. 1. Mean values ofN0 2 and NO (ppm)obtained by personalsampling, consideredfor job categories:o 0,5 1,5 2 2,5 3 3,5Fig. 2.Prevalence ofcoughand expectorationin workers and controlsMean Values (ppm)35%30%25%20% +- ---15% +-----10% +---15% +---10% +-_...1...-__COUGH EXPECTORATIONo CONTROLS• WORKERSInt. J. Immunopatho\. Pharmacol. 9550%40%30%20%10%4Worker Groups- COUGHo EXPECT.5Fig. 3. Prevalence of cough andexpectoration in workers , divided byjob categories (the % is calculated forthe number of workers in each jobcategory).Group 1 = Drivers; 2 = Machineoperators; 3 = Miners; 4 = Carpenters;5 = Electricians/ AssistantsFig. 4. % Modification in FEV1 (IiFEV1)after shift work, in controls and workersin the two tunnels evaluated.FEV1Variations1,5,- - - - - - - - ---,0,5c 00:re:.....-0,5ro o Controls>0-1 • "Carlone" tunn el~ n 'Rovigo" tunnel0-1,5-2-2,5The prevalence of symptoms, obtained fromthe analysis of questionnair,es, for controls andworkers, divided also for job categories and workingtunnels, is shown in figs . 2-3. Smokers presentedhigher significant prevalence of cough andexpectoration respect to non smokers (respectively:22% vs 11%; 26% vs 14%). The functionalrespiratory data are reported in Tab. II .In Fig. 4 the variation of FEV I (~FEV I aftershift work) is shown in workers and controlsbetween the registration at 7.00 a.m and at 2 p.m.The~PEFshows the same trend with less significantmodification. There were no significant variationsofdaily PEF evaluations (amplitude % mean daily,amplitude % mean weekly). The linear regressionanalysis showed that variables capable ofinfluencingthe decrease in FEV I and PEF are: smoke habits,work in worse polluted conditions and executionof spirometric tests after shift-work (Tab.III).DISCUSSIONSpirometric data evidenced lower values inthe group ofworkers compared to controls. Subjectsworking in the "Rovigo" tunnel (where highervalues of environmental dusts were evidenced)showed lower values of FEV 1 and PEF comparedto workers in the other tunnel, with similar smo-king habits. An annual loss of FEVI related towork exposure is reported by some A.A. (3,8).Tunnel construction workers are exposed to avariety of risk agents, including total and silicadust, diesel exhaust fumes , nitrogen dioxide; themixture ofexpositions probably induces the declinein spirometric parameters.All spirometric values were lower in smokerscompared to non-smokers and former smokers.The prevalence of cough and expectoration was96 G. ARCANGELI ET AL.higher in workers and smokers showing thatenvironmental work exposure and smoking habitscan influence those kinds ofsymptoms; the increasein chronic obstructive pulmonary disease is welldocumented in smokers and suspected in heavyconstruction workers (l,8).The dFEV I after shift work shows a significantdecrease in workers. The test was performed at7.00 a.m., before starting work activity, and at2.00 p.m., at the end of shift work. The dPEFshows the same trend with less significantmodification. The most used spirometric parametershave a circadian rhythm, with the lowest values inthe early morning and the highest values in theafternoon (9). Therefore, considering the circadianrhythm, the results obtained are underestimatedand the real decrease in FEV I and PEF is to beconsidered more evident. The effect is clearer inthe "Rovigo" tunnel where environmental workingconditions are worse. A temporary reduction inlung function was demonstrated in tunnel workersexposed to blasting fumes (10) and in normalhumans after exposure to nitrogen dioxide (11).Multivariate analysis highlights the fact thatvariables capable of influencing a decrease inFEV I and PEF are smoking habits, working inworse polluted conditions and execution ofspirometric tests after shift-work.On the whole, the results of this study showthat some physiologic parameters appear alteredin tunnel construction workers and suggest thatbetter control of their occupational exposure isneeded.REFERENCESI. Sullivan P.A., K.M. Bang, F.J. Hearl and G.R. Wagner.1995. Respiratory disease risks in the construction industry.Occup. Med. 10:313.2. Bakke B., P: Stewart, B. U1vestad and W. Eduard.2001. Dust and gas exposure in tunnel constructionwork. A.I.H.A.J. 62:457.3. U1vestad B., B. Bakke, E: Melbostad, P. Fugherund,J. Kongerund and M.B. Lund. 2000. Tunnel workersare at increased risk of obstuctive pulmonary disease.Thorax 55:277.4. Kessel R., M. Redl, R. Mauermayer and G.J. Praml.1989. Changes in lung function after working with theshotcrete lining method under compressed conditions.Br. J. Ind. Med. 46: 128.5. Blomberg A., M.T. Krishna, R. Helleday, M. Soderberg.,M.C. Ledin, F.J. Kelly, A.J. Frew, S.T. Holgate andT. Sandstrom. 1999. Persistent airway inflammationand Iung function responses after repeated daily exposureto nitrogen dioxide. Am. J. Respir. Crit. Care 159:536.6. National Institute for Occupational Safety and Health(NIOSH). 1998. Silica, Crystalline, by XRD Method7500. In NIOSH Manual of Analytical Methods, 4th ed.(DHS publication no. 98-1 19) Cincinnati, OH, USA7. American Thoracic Society. 1987. Standardization ofspirometry: 1987 update. Am. Res. Respir. Dis. 136:1285.8. U1vestad B., B. Bakke, W. Eduard W, J. Kongerundand M.B. Lund. 2001. Cumulative exposure to dustcauses accelerated decline in lung function in tunnelworkers. Occup. Environ. Med. 58:663.9. Quackenboss J.J., M.D. Lebowitz and M.Krzyzanowski. 1991.The normal range ofdiurnal changesin peck expiratory flow rates. Relationship to symptomsand respiratory disease. Am. Rev. Respir. Dis. 143:323.10. Bakke B., B. Ulvestad B, P. Stewart, M.B. Lund andW. Eduard. 2001. Effects of blasting fumes on exposureand short-term lung function changes in tunnel constructionworkers. Scand. J. Work Environ. Health 27:250.II. Frampton M.W., P.E. Morrow and C. Cox. 1991.Effects of nitrogen dioxide exposure on pulmonary functionand airway reactivity in normal humans. Am. Rev. Respir.Dis. 143:522.

Respiratory risks in tunnel construction workers

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Respiratory risks in tunnel construction workers

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