Malgorzata Pawlaczyk-Luszczynska

Ototoxic effects of occupational exposure to styrene and co-exposure to styrene and noise.

Learning ObjectivesRecall the reported effects of exposure to styrene and noise on the cochlear hair cells and hearing function in rats.Describe which possible confounding factors were and were not controlled for in this study, and what the results indicate about the respective ototoxic effects on humans of exposure to styrene and noise.Characterize the effects in humans of isolated and combined exposure to styrene and noise. Ototoxicity of styrene and the synergistic action of styrene and noise have been shown in rats. The respective data in humans are scarce and equivocal. This study evaluated the effects of occupational exposure to styrene and combined exposures to styrene and noise on hearing. The study group, comprised of 290-yacht yard and plastic factory workers, was exposed to a mixture of organic solvents, having styrene as its main compound. The reference group, totaling 223 subjects, included (1) white-collar workers, exposed neither to solvents nor noise and (2) metal factory workers, exposed exclusively to noise. All subjects were assessed by means of a detailed questionnaire and underwent otorhinolaryngological and audiometric examinations. Multiple logistic regression analysis revealed almost a 4-fold (or 3.9; 95% CI = 2.4–6.2) increase in the odds of developing hearing loss related to styrene exposure. The factors adjusted for were: age, gender, current occupational exposure to noise, and exposure to noise in the past. In cases of the combined exposures to styrene and noise, the odds ratios were two to three times higher than the respective values for styrene-only and noise-only exposed subjects. The mean hearing thresholds—adjusted for age, gender, and exposure to noise—were significantly higher in the solvent-exposed group than in the unexposed reference group at all frequencies tested. A positive linear relationship existed between an averaged working life exposure to styrene concentration and a hearing threshold at the frequencies of 6 and 8 kHz. This study provides the epidemiological evidence that occupational exposure to styrene is related to an increased risk of hearing loss. Combined exposures to noise and styrene seem to be more ototoxic than exposure to noise alone.

Effects of coexposure to noise and mixture of organic solvents on hearing in dockyard workers.

Questionnaire and audiometric data of 701 dockyard workers (517 noise and organic solvent mixture-exposed and 184 noise-only-exposed) were referred to 205 control subjects not exposed to either noise or solvents. The odds ratio (OR) of hearing loss was significantly increased by approximately 3 times in the noise-only group and by almost 5 times in the noise and solvent group. A moderate effect of solvent ototoxicity, in addition to noise, was observed on hearing threshold at a frequency 8 kHz. ORs for hearing loss were 1.12 for each increment of 1 year of age, 1.07 for every decibel of lifetime noise exposure (dB-A), and 1.004 for each increment of the index of lifetime exposure to solvents. The results suggest an additive damaging effect of coexposure to noise and organic solvents to the auditory organ.

Exacerbation of noise-induced hearing loss by co-exposure to workplace chemicals

BACKGROUND : Numerous organic solvents applied in industry, like toluene, styrene, xylene and n-hexane have been demonstrated to impair hearing in animals. However, the effects of exposure to a given organic solvent and the interaction of noise and solvents on hearing in humans are still not fully recognized. STUDY DESIGN : The study was aimed to assess the effects of occupational exposure to solvents alone or in combination with noise on hearing in 1117 employees of yacht, ship, plastic, shoe, and paint and lacquer industry. These persons were exposed either to the mixture of organic solvents with xylene as the main component, or predominantly to styrene, or to the mixture of n-hexane and toluene. Detailed questionnaire data and pure-tone audiometry were compared with data of the reference group that included white collar workers, exposed neither to solvents nor noise and metal factory workers exposed to noise only. In all statistics, the confounding factors were recognized as gender, age, exposure to noise, and other variables occurring at a different rate in study and reference group. RESULTS : Odds ratio (OR) of hearing loss related with the particular exposure to chemicals was 2.4 (95%CI 1.59-3.74) in case of solvent mixture, 3.9 (95%CI 2.4-6.2) in case of styrene and 5.3 (95%CI 2.6-10.9) in case of n-hexane and toluene exposure. The odds of developing hearing loss substantially increased in the case of combined exposure to organic solvents and noise as compared to isolated exposure to each of these hazards. The highest OR (over 20-fold) was demonstrated in subgroups of subjects exposed simultaneously to noise and two ototoxic solvents (i.e. styrene and toluene or n-hexane and toluene). The mean hearing thresholds were significantly higher in the solvent-exposed groups than in the reference group. The differences in thresholds were observed at high frequencies in the solvent mixture- and n-hexane + toluene-exposed groups and at all frequencies in the styrene-exposed group. A positive linear relationship existed between exposure to solvents and hearing thresholds at high frequencies. CONCLUSIONS : The results of the study provide the epidemiological evidence that exposure to organic solvents in humans is associated with an increased risk of hearing loss. The simultaneous exposure to organic solvents and noise seems to enhance the hearing deficit if compared with isolated exposures.

Effects of impulse noise on transiently evoked otoacoustic emission in soldiers Efectos del ruido impulsivo sobre las emisiones otoacústicas evocadas por transitorios en soldados

The aim of the study was to assess the effects of exposure to impulse noise on TEOAE, as compared to PTA. The study comprised 92 soldiers, subjected to impulse noise during military service. The control group consisted of secondary school students, not exposed to noise. Extended high frequency PTA, and TEOAE were recorded before and after one year of military service. The total level of noise and spectrum analysis were performed for all kinds of weapons, separately. The highest levels of noise for weapons were related to frequencies from 1.6–16 kHz. After military service significant deterioration of hearing was observed on average by 6 dB exclusively at the frequencies of 10 and 12 kHz. TEOAE reduction was registered predominantly at frequencies of 2, 3 and 4 kHz, with the greatest decrease at 2 kHz (p<0.02). The control group did not show any significant audiometric changes as well as TEOAE during the time of experiment.

Evaluation of annoyance from low frequency noise under laboratory conditions

The aim of the study was to investigate the annoyance of low frequency noise (LFN) at levels normally prevailing at workplaces in control rooms and office-like areas. Two different laboratory experiments were carried out. The first experiment included 55 young volunteers and the second one comprised 70 older volunteers, categorized in terms of sensitivity to noise. The subjects listened to noise samples with different spectra, including LFNs at sound pressure level (SPL) of 45-67 dBA, and evaluated annoyance using a 100-score graphical rating scale. The subjective ratings of annoyance were compared to different noise metrics. In both the experiments, there were no differences in annoyance assessments between females and males. A significant influence of individual sensitivity to noise on annoyance rating was observed for some LFNs. Annoyance of LFN was not rated higher than annoyance from broadband noises without or with less prominent low frequencies at similar A-weighted SPLs. In both the experiments, median annoyance rating of LFN highly correlated with A-weighted SPL (L(Aeq,T)), low frequency A-weighted SPL (L(LFAeq,T)) and C-weighted SPL (L(Ceq,T)). However, it is only the two latter noise metrics (i.e. L(LFAeq,T) and L(Ceq,T)) which seem to be reliable predictors of annoyance exclusively from LFN. The young and older participants assessed similar annoyance from LFN at similar L(LFAeq,T) or L(Ceq,T) levels. Generally, over half of the subjects were predicted to be highly annoyed by LFN at the low frequency A-weighted SPL or C-weighted SPL above 62 and 83 dB, respectively.

Annoyance Related to Low Frequency Noise in Subjective Assessment of Workers

The aim of this study was to assess annoyance related to low frequency noise (LFN) in employees of the control rooms and office-like areas. Subjects were 276 workers, aged 26–62 years, exposed to noise at A-weighted sound pressure level (SPL) of 41–66 dB. They were asked to assess noise annoyance at their workplace using a 100 point graphical scale. The subjective ratings were compared with various noise metrics and objective evaluations based on proposed LFN exposure criteria for occupational settings. There was a difference in annoyance assessment related to noise with and without (or with less prominent) low frequency content. Low frequency noise was rated as more annoying even though it was at lower dBA levels. Among the noise metrics, the low frequency A-weighted SPL yielded the highest correlation with subjective evaluations of LFN. There was also a quite good agreement between individual annoyance ratings and limit excesses corresponding to preliminary Swedish and Polish exposure criteria.

Does Low Frequency Noise at Modarate Levels Influence Human Mental Performance

The aim of this study was to assess the influence of low frequency noise (LFN) at levels normally occurring in the industrial control rooms on human mental performance (attention, visual perception and logical reasoning) and subjective well-being. Subjects were 191 male volunteers categorised in terms of subjective sensitivity to noise in general. They performed standardised tests: the Signal Detection Test (test I), the Stroop Colour-Word Test (test II), and two sub-tests of the General Aptitude Test Battery, i.e. the Math Reasoning Test (test III) and the Comparing of Names Test (test IV). Three different acoustic conditions were used in the between-subjects design: the background laboratory noise of about 30 dB(A), LFN, and a broadband noise without dominant low frequency components (reference noise) at 50 dB(A). Each subject was tested only once in random-assigned exposure conditions. Generally, no significant differences in performance related to exposure conditions were noted. Some of the results from test I and test II were influenced by sensitivity to noise. However, there were no significant differences between high- and low-sensitive subjects during exposure to LFN. The annoyance of LFN and reference noise was rated higher than that of the background noise. Subjects highly-sensitive to noise reported higher annoyance due to LFN in comparison with low-sensitives. No significant differences related to noise sensitivity in annoyance assessment of background and reference noises were noted. In conclusion, no effects due to LFN on mental performance compared to background and reference noises were found.

Proposal of New Limit Values for Occupational Exposure to Infrasonic Noise in Poland

Proposals for new Polish limits for occupational exposure to infrasonic noise were put forward based on a comprehensive analysis of literature data concerning the effects of infrasound on humans, the existing standards and occupational exposure limits, and results of our own infrasonic noise measurements. It is suggested that according to the health-based criteria an equivalent continuous G-weighted sound pressure level normalised to a nominal 8–hour working day or 40–hour working week should not exceed 102 dB. Additionally, an overall unweighted peak sound pressure level should not be higher than 145 dB.

Assessment of annoyance due to wind turbine noise

The overall aim of this study was to evaluate the perception and annoyance of noise from wind turbines in populated areas of Poland. The study group comprised 156 subjects. All subjects were interviewed using a questionnaire developed to enable evaluation of their living conditions, including prevalence of annoyance due to noise from wind turbines, and the self-assessment of physical health and wellbeing. In addition, current mental health status of respondents was assessed using Goldberg General Health Questionnaire GHQ-12. For areas where respondents lived, A-weighted sound pressure levels (SPLs) were calculated as the sum of the contributions from the wind power plants in the specific area. It has been shown that the wind turbine noise at the calculated A-weighted SPL of 30−48 dB was perceived as annoying outdoors by about one third of respondents, while indoors by one fifth of them. The proportions of the respondents annoyed by the wind turbine noise increased with increasing A-weighted sound pressure...

Community response to noise: Research in Central, Eastern and South-Eastern Europe and Newly Independent States

The systems of public complaints on environmental noise were reviewed in seven countries of Central and Eastern Europe (CEE), South-East Europe (SEE), and Newly Independent States (NIS). Public complaints remain an important issue due to differences in public sensitivity to noise and due to several cases where a measurement of noise intensity does not give a satisfying solution to the problem. The unresolved problem remaining in the residential neighborhoods is the noise from pubs and restaurants that are open until late in the night. In our review, we compiled information on the institutions responsible for the implementation of environmental noise legislation and organizations that are responsible for dealing with public complaints. Information on activities for increasing public awareness on hazards rising from environmental noise and the role of civil initiative was explored. In seven countries, and among them, Slovenia, Lithuania, Latvia, Slovakia, The Former Yugoslav Republic of Macedonia, Serbia, and Poland, the responsibilities and duties are shared among different institutions at national and regional levels, depending on the noise source. The problem of gathering information on complaints and using it for improving the wellbeing and health of citizens remains often difficult and unsolved.