Acute and chronic respiratory effects of sodium borate particulate exposures.

This study examined work-related chronic abnormality in pulmonary function and work-related acute irritant symptoms associated with exposure to borate dust in mining and processing operations. Chronic effects were examined by pulmonary function at the beginning and end of a 7-year interval. Time-specific estimates of sodium borate particulate exposures were used to estimate cumulative exposure during the study interval. Change in pulmonary function over the 7 years was found unrelated to the estimate of cumulative exposure during that interval. Exposure-response associations also were examined with respect to short-term peak exposures and incidence of five symptoms of acute respiratory irritation. Hourly measures of health outcome and continuous measures of particulate exposure were made on each subject throughout the day. Whenever a subject reported one of the irritant symptoms, a symptom intensity score was also recorded along with the approximate time of onset. The findings indicated that exposure-response relationships were present for each of the specific symptoms at several symptom intensity levels. The associations were present when exposure was estimated by both day-long and short-term (15-min) time-weighted average exposures. Associations persisted after taking account of smoking, age, and the presence of a common cold. No significant difference in response rate was found between workers exposed to different types of sodium borate dusts

Utjecaj izloženosti 1,6-heksametilen diizocijanatu (HDI) na vršni ekspiratorni protok u autolakirera u Iranu

The aim of this study was to investigate the effects of occupational exposure to 1,6-hexamethylene diisocyanate (HDI) on peak flowmetry in automobile body paint shop workers in Iran. We studied a population of 43 car painters exposed to HDI at their workplaces. Peak expiratory fl ow was tested for one working week, from the start to the end of each shift. Air was sampled and HDI analysed in parallel, according to the OSHA 42 method. Daily and weekly HDI exposure averages were (0.42±0.1) mg m-3 and (0.13±0.05) mg m-3, respectively. On painting days, 72 % of workers showed more than a 10 % variation in peak expiratory fl ow. Inhalation exposure exceeded the threshold limit value (TLV) ten times over. This strongly suggests that HDI affected the peak fl owmetry in the studied workers.Cilj je ovog ispitivanja bio utvrditi vršni protok u 43 iranska autolakirera profesionalno izložena 1,6-heksametilen diizocijanatu (HDI). Vršni ekspiratorni protok testiran je tjedan dana na početku i kraju svake smjene. Uzorkovanje i mjerenje HDI-ja u zraku radilo se istodobno s testiranjem vršnoga protoka, prema metodi OSHA 42. Prosječna dnevna izloženost radnika HDI-ju iznosila je (0.42±0.1) mg m-3, a tjedna (0.13±0.05) mg m-3. U 72 % radnika vršni ekspiratorni protok tijekom dana varirao je više od 10 %. Radnici su udisali deset puta više razine HDI-ja od graničnih te je moguće da je HDI utjecao na mjerenja plućne funkcije

Susceptibility of Mycobacterium immunogenum and Pseudomonas fluorescens to Formaldehyde and Non-Formaldehyde Biocides in Semi-Synthetic Metalworking Fluids

Mycobacterium immunogenum, a newly identified member of the Mycobacterium chelonae_M. abscessus complex is considered a potential etiological agent for hypersensitivity pneumonitis (HP) in machine workers exposed to contaminated metalworking fluid (MWF). This study investigated the biocidal efficacy of the frequently applied commercial formaldehyde-releasing (HCHO) biocides Grotan and Bioban CS 1135 and non-HCHO type biocides Kathon 886 MW (isothiazolone) and Preventol CMK 40 (phenolic) toward this emerging mycobacterial species (M. immunogenum) in HP-linked MWFs, alone and in presence of a representative of the Gram-negative bacterial contaminants, Pseudomonas fluorescens, using two semi-synthetic MWF matrices (designated Fluid A and Fluid B). Relative biocide susceptibility analysis indicated M immunogenum to be comparatively more resistant (2–1600 fold) than P. fluorescens to the tested biocides under the varied test conditions. In terms of minimum inhibitory concentration, Kathon was the most effective biocide against M. immunogenum. Fluid factors had a major effect on the biocide susceptibility. Fluid A formulation provided greater protective advantage to the test organisms than Fluid B. Fluid dialysis (Fluid A) led to an increased biocidal efficacy of Grotan, Kathon and Preventol against M. immunogenum further implying the role of native fluid components. Used fluid matrix, in general, increased the resistance of the two test organisms against the biocides, with certain exceptions. M. immunogenum resistance increased in presence of the co-contaminant P. fluorescens. Collectively, the results show a multifactorial nature of the biocide susceptibility of MWF-colonizing mycobacteria and highlight the importance of more rigorous efficacy testing and validation of biocides prior to and during their application in metalworking fluid operations

Particulate matter produced during commercial sugarcane harvesting and processing: a respiratory health hazard?

Emissions from sugarcane burning are known to impact on the respiratory health of sugar estate workers and local populations. Despite this, there have been few studies on occupational and ambient exposures and risks from airborne particulate matter (PM) associated with field burning and ash re-suspension. From workplace monitoring on sugarcane estates in two different South American countries in 2010 and 2011, median concentrations of airborne PM10 (particulate matter nominally <10 μm in diameter) were found to be statistically much higher during pre-harvest sugarcane burning (1807 μg m−3) than during either sugarcane cutting after burning (∼123 μg m−3) or in the sugarcane processing factory (∼175 μg m−3). Median PM10 measurements in ambient scenarios, for example in the sugarcane fields before the burning or during 24 h measurements in neighboring villages (bordering the sugarcane plantation), were much lower, between 18 and 37 μg m−3. From the analysis of size-selective samples of airborne PM10, collected during sugarcane field burning, cutting and ambient periods, almost all (∼96 wt %) fell within the ‘respirable’ fraction (<4 μm aerodynamic diameter), with a mass median aerodynamic diameter (MMAD) of 1.1 μm. Residual ash from field and bagasse burning, characterised using Scanning Electron Microscopy (SEM) with X-ray elemental analysis, was found to contain carbonaceous and silicate-dominated particles in the PM0.5 and PM0.5-2.5 size ranges and fibres from <10 to over 50 μm in length. Only a small proportion of the field burning ash (average 0.6 vol %) and bagasse ash (average 1.3 vol %) was in the respirable fraction. However, from grinding experiments, which simulate disaggregation as a result of disturbance during harvest or bagasse ash removal, the ash was fragile and easily broken down into thoracic particulate (<10 μm aerodynamic diameter) and, in some instances, created respirable-sized PM. From exposure calculations, the 8 h time weighted average (TWA) concentrations of PM10, during the different measurement scenarios, were found to be below occupational exposure limits (OELs; 5000 μg m−3 for respirable PM). Ambient PM10 exposure of residents surrounding the sugarcane plantations was found to be below the WHO air quality guideline (50 μg m−3 as a 24 h mean). The relative risk calculated for ‘all cause’ mortality from exposure of nearby residents to PM10 generated by sugarcane burning was found to be 3%. The concentrations of PM10 produced during the processing of sugarcane were high (up to 21.5 mg m−3), which is concerning given that re-suspended particles of ash in the fields and processing plant have been previously shown to contain potentially toxic cristobalite. PM produced during sugarcane burning, and during extended periods of local exposure to the smoke and re-suspended ash, therefore, should be considered as both a potential acute and chronic respiratory health hazard. This issue will become increasingly important with the forecasted rise in sugarcane production for biofuels