Workplace Air Research Articles

Determination of Nitrobenzenes in Air by a Needle Trap Device (NTD) and Gas Chromatography-Mass Spectrometry (GC-MS)

A simple needle-trap device (NTD) coupled with gas chromatography-mass spectrometry (GC-MS) was developed to determine trace levels of nitrobenzenes (NBs) in workplace air. The NTD with sorbent inside the needle was employed for the quantification of nitrobenzene, o-nitrotoluene, m-nitrotoluene, p-nitrotoluene, o-nitrochlorobenzene, m-nitrochlorobenzene, and p-nitrochlorobenzene. The optimum temperature and time for desorption of analytes were 270 °C and 4 min, and parameters such as sampling flow rate, breakthrough volume, and storage capability were also optimized. The limits of detection and quantification were in the ranges of 1.8 × 10−4–1.1 × 10−3 and 5.9 × 10−4–3.6 × 10−3 mg m−3, respectively. The developed protocol was successfully applied for the determination of NBs in vehicle repair plants where the highest detected concentration was 0.11 mg m−3. The established NTD-GC-MS generally applies to monitoring trace levels of NBs in the air.

Potential health risks of inhaling hazardous chemical exposures at fuel stations: a pilot study in a hot, arid environment

In recent years, there has been a growing focus on the issue of exposure to hazardous chemical compounds and the potential health risks associated with them. Fuel stations play a critical role in society, supporting the transportation industry and serving the general public. However, the routine activities at these stations expose workers and customers to dangerous chemical compounds, posing potential health risks. As part of a pilot study, the exposure of workers and customers to hazardous chemical compounds at fuel stations in Kuwait, characterized by its hot and arid environment, was investigated. The study specifically looked at volatile organic compounds (VOC) concentration and their effects on human health. Three hundred-eight air samples were collected in a hot, arid environment, focusing on fuel stations. Two sampling methods were used in this pilot study: personal inhalation exposure using active sampling and workplace air sampling using passive sampling. Samples were collected in fuel filling areas, indoor control rooms, and through personal exposures, adhering to ISO procedures (EPA TO-17). The study also assessed the non-carcinogenic and carcinogenic risks to human health to potential exposure to hazardous hazardous chemicals. The findings revealed that hazardous chemicals levels in the pump area were lower than those in the indoor control rooms. Workers’ inhalation exposure to hazardous chemicals remained below the international occupational exposure limit (OEL). However, the study identified unsafe inhalation exposure levels to Benzene, which could have adverse carcinogenic effects. In contrast, exposure to ethylbenzene was found to be within safe limits, with no associated carcinogenic effects. This study underscores the importance of identifying the risks associated with exposure to hazardous chemical compounds to minimize human health risks and promote a safe working environment.

An amide-based covalent organic framework chemically anchored on silica nanoparticles for headspace microextraction sampling of halogenated hydrocarbons in air

A needle trap device (NTD) was developed using an amide-based covalent-organic framework (COF), chemically bonded to silica nanoparticles. The NTD was coupled with gas chromatography-flame ionization detection (GC-FID) and employed for the headspace microextraction analysis of halogenated hydrocarbons (HHCs) in the air. The adsorbent was characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FE-SEM) techniques.Optimal values for the experimental variables were assessed using response surface methodology (RSM) with a central composite design (CCD), thereby reducing the number of experiments, material consumption, costs, and time. The optimal values for desorption time and temperature were obtained 5 min and 260 °C, respectively. Breakthrough volume (BtV) was studied over the range of 0.5 - 3 times the occupational exposure limit (OEL) and its optimal value was found to be 1200 mL. The optimal sampling temperature and relative humidity (RH) were obtained 20 °C, and 15 %, respectively. The limits of detection (LODs) and limits of quantification (LOQs) were ranged from 0.013 to 0.077 μg l-1 and 0.041 to 0.21 μg l-1, respectively, with a linear dynamic range (LDR) of 0.04 to 100 μg l-1. The method's repeatability and reproducibility (RSD %) were observed over the ranges of 5.3 - 6.4 % and 4.7 -6.9 %, respectively. A statistically validated agreement was observed between the NTD-GC-FID method and the NIOSH 1003 standard procedure for the sampling and determination of HHCs in real workplace air samples, demonstrating the reliability and accuracy of the developed approach.

Determination of 8 N-nitrosamines in the workplace air by GC-MS/MS method

Objective: To establish a method for the determination of eight N-nitrosamines (N-nitrosodimethylamine, N-nitrosodimethylamine, N-nitrosomethylmethylamine, N-nitrosodibutylamine, N-nitrosopropylamine, N-nitrosomorpholine, N-nitrosodianiline and N-nitrosopiperidine) in the air of workplace by gas chromatography-tandem mass spectrometry (GC-MS/MS) . Methods: From January to August 2023, eight N-nitrosamines in the air of workplace were collected by ThermoSorb/N column, eluted with 4 ml methanol-dichloromethane (1∶1 volume ratio), separated by VF-624 ms capillary column, detected by multiple reaction monitoring mode and quantified by external standard method. The detection limit and precision of the method were also analyzed. Results: The linear range of the method for the determination of eight N-nitrosamines was 1.0-20.0 μg/L, the correlation coefficient was 0.9993-0.9999, the detection limit was 0.051-0.132 μg/L, and the minimum quantitative concentration was 0.030-0.078 μg/m(3) (calculated by collecting 22.5 L of air sample and eluting with 4.0 ml stripping liquid). The within-run precisions were 2.05%-6.89% and the between-run precisions were 2.41%-8.26%. The desorption rates were 67.20%-102.60%. The sample can be kept at least 7 days at 4 ℃. Conclusion: GC-MS/MS method for the determination of eight N-nitrosamines in workplace air has high sensitivity and good precision, and can accurately determine the content of eight N-nitrosamines in workplace air.

67 Criteria for the assessment of the percutaneous absorption of hazardous substances at the workplace – The German MAK Commission approach

Abstract The uptake of hazardous substances at the workplace through the skin can be one major route of exposure and therefore add to the occupational health risk for employees. More than one third of all substances with a limit value in workplace air in Germany have been designated with ‘H’ by the MAK Commission of the Deutsche Forschungsgemeinschaft (DFG), indicating that the percutaneous absorption under workplace conditions can make a significant contribution to the systemic exposure of an employee. The recommendations of the MAK Commission are one major source for regulatory decisions taken by the German Ministry of Labor and Social Affairs for sustaining health and safety in the work area. This presentation summarizes the general approach of the MAK Commission’s working group on percutaneous absorption, the selection and ranking of data (workplace studies, animal studies, in vitro studies, mathematical models or algorithms) as well as the quantitative criteria for an assignment with ‘H’. For the final assessment, the estimated absorbed amount of a substance is compared with the systemically tolerable amount extrapolated from the no observed adverse effect level (NOAEL). A designation with ‘H’ is recommended if the percutaneous uptake accounts for approximately 25 % or more of the tolerable quantity. Only in the case of genotoxic substances without limit values is the ability of a substance to cross the skin barrier sufficient in itself to recommend designation with an ‘H’. The assessment process as well as its merits and challenges are illustrated by some examples.

Establishment of collection methods and laboratory testing methods for active pharmaceutical ingredient in the workplace air

Objective: To establish collection methods and laboratory testing methods for qualitative and quantitative analysis of 9 typical active pharmaceutical ingredient in the workplace air. Methods: In December 2021, a mixed solution of nine analytes was prepared and then dispersed in aerosol state to simulate sampling. Glass fiber filter membrane was selected as air collector and collected active pharmaceutical ingredient in the air at a rate of 2.0 L/min for 15 minutes. Then, the obtained filter membrane samples were eluted with 25%ACN/75%MeOH. Finally, the eluent was qualitatively and quantitatively analyzed with liquid chromatography-triple quadrupole mass spectrometer. Results: This method could effectively collect active pharmaceutical ingredient in the air, with an average sampling efficiency of more than 98.5%. The linear correlation coefficient r was greater than 0.9990. The lower limit of quantification for each analyte ranged from 0.6~500.0 ng/ml, and the average recovery rate ranged from 97.6%~102.5%. Conclusion: This method could simultaneously collect 9 active pharmaceutical ingredient in the workplace air, and could provide accurate qualitative and quantitative analysis in subsequent laboratory tests.

Вредные вещества в воздухе рабочей зоны горнодобывающего сектора металлурги-ческой промышленности как факторы риска для здоровья работников (аналитический обзор)

Working conditions at non-ferrous metallurgical enterprises typically involve exposure to a whole set of harmful chemicals present in occupational air. These chemicals contribute to the development of pathologies in workers, respiratory diseases in particular. Research literature was analyzed using bibliographic databases in order to summarize available information on effects produced by harmful chemicals in workplace air on health of workers employed at mining enterprises. Respiratory diseases such as pneumoconiosis, acute and chronic dust bronchitis prevail among occupational pathologies typical for underground miners. Acute and chronic bronchitis prevail among respiratory diseases as health disorders resulting in temporary disability of miners dealing with non-ferrous metal mining. Huge amounts of dust appear in occupational air at mining enterprises due to drilling, blasting and ore crushing. Priority chemicals found in workplace air in mining industry include several carcinogens such as nickel, lead, formaldehyde, cadmium, and benzo(a)pyrene. There is a unidirectional effect produced by sulfur dioxide, nickel, nitrogen oxides, acrolein, formaldehyde, cadmium, and particular matter on the respiratory organs. The nervous system can be affected by manganese, lead, and selenium; the blood, by nickel, lead, and carbon oxide; the cardiovascular system, by carbon oxide and selenium. Working conditions of underground miners in non-ferrous metallurgy involve intensive exposure to chemicals in occupational air, which create health risks of occupational respiratory diseases and malignant tumors. Diseases of the nervous, immune, cardiovascular systems and the blood are also possible. When planning a set of preventive activities, it is advisable to identify groups of work-related diseases caused, among other things, by a specific chemical factor.

Harmful chemicals in occupational air in the ore mining sector of the metal industry as occupational health risk factors (Analytical review)

Working conditions at non-ferrous metallurgical enterprises typically involve exposure to a whole set of harmful chemicals present in occupational air. These chemicals contribute to the development of pathologies in workers, respiratory diseases in particular. Research literature was analyzed using bibliographic databases in order to summarize available information on effects produced by harmful chemicals in workplace air on health of workers employed at mining enterprises. Respiratory diseases such as pneumoconiosis, acute and chronic dust bronchitis prevail among occupational pathologies typical for underground miners. Acute and chronic bronchitis prevail among respiratory diseases as health disorders resulting in temporary disability of miners dealing with non-ferrous metal mining. Huge amounts of dust appear in occupational air at mining enterprises due to drilling, blasting and ore crushing. Priority chemicals found in workplace air in mining industry include several carcinogens such as nickel, lead, formaldehyde, cadmium, and benzo(a)pyrene. There is a unidirectional effect produced by sulfur dioxide, nickel, nitrogen oxides, acrolein, formaldehyde, cadmium, and particular matter on the respiratory organs. The nervous system can be affected by manganese, lead, and selenium; the blood, by nickel, lead, and carbon oxide; the cardiovascular system, by carbon oxide and selenium. Working conditions of underground miners in non-ferrous metallurgy involve intensive exposure to chemicals in occupational air, which create health risks of occupational respiratory diseases and malignant tumors. Diseases of the nervous, immune, cardiovascular systems and the blood are also possible. When planning a set of preventive activities, it is advisable to identify groups of work-related diseases caused, among other things, by a specific chemical factor.

150 PDC on workplace air exposure assessment using freeware apps Part I: Basic characterisation and measurement processing

150 PDC on workplace air exposure assessment using freeware apps Part I: Basic characterisation and measurement processing

Occupational prevalence rates in metallurgists in the Sverdlovsk Region

Introduction. The previous analysis conducted for 2003–2022 showed ferrous industry employing over twenty five thousand people to make the most contribution to occupational disease incidence rates in the Sverdlovsk Region since 68.6 % of its workers are affected by industrial exposures above occupational safety standards. The purpose of the study was the analysis of occupational disease incidence in workers of a ferrous metal processing plant of the Sverdlovsk Region and assessment of the impact of adverse factors of the work environment and industrial processes on its rates.
 Materials and methods. Long-term occupational disease incidence in workers of the ferrous metal processing plant has been analyzed by the causative agent, nosology, age, gender, and job. Data of the reporting form No. 1-T (working conditions) for the study period have been scrutinized; comparative data evaluation by working conditions and occupational disease incidence rates has been made.
 Results. High incidence rates of work-related diseases in the metallurgists indicate to a significant proportion (70 %) of them to be exposed to occupational hazards. The established 20-year rate at the enterprise was 5.6 and 1.6 times higher than the regional and Russian averages in this industry, respectively. Increased gas and dust levels in the workplace air remain the leading health risk factors in ferrous metallurgy.
 Limitations. The limitation of this study was the lack of annual data on workers by job preventing calculation of job-specific disease incidence rates per 10 thousand workers.
 Conclusion. Despite the substantial modernization of the metallurgical complex, metal processing technology still does not comply with safety standards, thus requiring the development and implementation of science-based preventive measures aimed at maintaining workers’ health.

Comparative toxicological-hygienic assessment, structural-morphological, physicochemical characteristics, and virucidal properties of new nanopowder materials TiO2 and TiO2@Ag

In order to address safety concerns related to the acquisition and utilization of TiO2 and TiO2@Ag nanomaterials, as well as to investigate their disinfectant and biological effects, the structural-morphological, morpho­metry, toxicological, cytotoxic, and virucidal properties of these specified nanomaterials have been studied through experiments conducted on laboratory animals and in vitro. It has been demonstrated that the TiO2@Ag nanocomposite exhibited distinct physicochemical characteristics: it consisted of TiO2 nanoparticles ranging in size from 13 nm to 20 nm and Ag nanoparticles ranging from 35 nm to 40 nm with 4.0 wt% of silver localized on the surface of titanium dioxide. The purity of the modification of synthesized nano-TiO2 and nano-TiO2@Ag has been confirmed. Acute intraperitoneal administration of nanopowders revealed LD50 values of 4783.30 mg/kg for nano-TiO2 and 724.44 mg/kg for nano-TiO2@Ag. A slight accumulation was observed upon repeated (28-fold) intragastric administration of nano-TiO2. The cumulative dose administered, which equated to 15.9 multiples of the LD50 (76040 mg/kg), did not result in animal mortality but led to retardation in body weight gain. TiO2 and TiO2@Ag nanopowders do not irritate the skin, induce mild conjunctival irritation, and may exhibit a weak sensitizing effect. Nano-TiO2 and nano-TiO2@Ag powders accumulate in the tissues of internal organs and cause damage to the liver, kidneys, and lungs of laboratory animals upon intraperitoneal administration. The most characteristic morphological signs of the toxic effect of nano-TiO2 on liver tissue were observed at a level of 67.7% (cytoplasmic vacuolization in hepatocytes), while in the case of nano-TiO2@Ag initial necrotic changes were at a level of 70.0% (hepatocytes with pyknotic nuclei). Immunoassay analysis has demonstrated that TiO2@Ag and TiO2 nanomaterials at concentrations of 30 µg/ml can enhance the functional activity of peripheral blood mononuclear cells in vitro by increasing the production of cytokines IL-1, IL-6, TNF-α, and IL-4 in donors (p<0.05). This indicates the potential for chronic inflammation and allergic reactions among synthesis operators. In the study of the impact of nanomaterials on murine germ cells, it has been established that they affect the activity of mitochondrial enzymes and exert a damaging effect on mitochondrial membranes and overall cell integrity. Estimated approximate safe exposure levels in the workplace air are 0.3 mg/m3 for nano-TiO2 and 0.2 mg/m3 for nano-TiO2@Ag. Nano-TiO2@Ag and nano-TiO2 at a concentration of 100 µg/ml exhibit pronounced extracellular virucidal activity against human adenovirus serotype 2. The TiO2@Ag nanocomposite has a less damaging effect on Нер-2 cells compared to nano-TiO2.

Zastosowanie chromatografii gazowej do oznaczania 1,4-dioksanu w powietrzu na stanowiskach pracy

1,4-Dioxane is a volatile liquid with a weak odor that dissolves well in water and most organic solvents. As a flammable liquid it poses a fire hazard. 1,4-Dioxane is unstable at increased temperature and pressure and can form explosive mixtures. It is mainly used as a solvent in the production of other chemicals, as a solvent for printing inks, coatings and adhesives, and as a laboratory reagent. According to the Regulation of the European Parliament and the Council (WE 1272/2008), 1,4-dioxane is classified as a carcinogen, flammable, eye and respiratory irritant. This article presents a method for the determination of 1,4-dioxane in workplace air, revised due to a proposed change in the maximum allowable concentration (MAC) value for this substance. The method involves adsorption of 1,4-dioxane on activated carbon, desorption with a mixture of propan-2-ol and carbon disulfide, and chromatographic analysis (GC-FID) of the resulting solution. The method allows for the determination of 1,4-dioxane in the concentration range of 2.2 to 44 mg/m3 (MAC 22 mg/m3 ) or 0.73 to 14.6 mg/m3 (MAC 7.3 mg/m3 ), i.e. 1/10 to 2 of the proposed value of the maximum allowable concentration. The method has been validated in accordance with PN-EN 482. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

Determination of dimethyl oxalate and diethyl oxalate in workplace air by high performance liquid chromatography

Objective: To establish a high performance liquid chromatography method for the simultaneous determination of dimethyl oxalate (DMO) and diethyl oxalate (DEO) in workplace air. Methods: From January 2022 to January 2023, air samples were collected by silica gel tubes, desorbed by acetonitrile, separated by C18 chromatographic column, detected by photo-array detector, and retention time was used to characterize and peak area was used to quantify at 210 nm wavelength. Results: The linear relationships of DMO and DEO were good, r>0.999. The detection limits of DMO and DEO were 0.39 and 0.52 μg/ml, respectively. The quantitative limit was 1.28 μg/ml for DMO and 1.72 μg/ml for DEO. Average desorption efficiency for DMO was 82.40%-92.72%, and DEO was 94.13%-97.69%. The intra-assay precision of DMO was 1.87%-6.18%, and DEO was 2.25%-3.31%. Inter-assay precision of DMO was 3.29%-5.73%, and DEO was 1.38%-2.94%. Average sampling efficiencies were 100% for both DMO and DEO. Breakthrough capacity of DMO was 37.61 mg (200 mg solid adsorbent), DEO was >28.11 mg (200 mg solid adsorbent). Samples should be stored at 4 ℃ for at least 7 days. Conclusion: This method is easy to operate and has strong practicability. All indicators meet the requirements of the specification, and it is suitable for the simultaneous determination of DMO and DEO in the workplace air.

Ion chromatography for the determination of n-butylamine in the workplace air

Objective: To establish a method for the determination of n-butylamine in the air of the workplace by ion chromatography. Methods: In February 2022, on-site sampling was carried out using an atmospheric sampler. N-butylamine was adsorbed by a neutral silica gel tube and then performed for qualitative and quantitative determination by ion chromatography after ultrasonic desorption with 10 mmol/L sulfuric acid solution. Results: The linear range of the method was 0.0375-100.0 μg/ml, the linear equation of the standard curve was y=0.0713x-0.0327, the correlation coefficient was 0.9992. The detection limit of the method was 11.25 μg/L, and the lower limit of quantification was 37.50 μg/L, the lowest quantitative concentration was 0.025 mg/m(3) (in term of sampling 7.5 L). The average desorption efficiency of the method was 91.50%-95.38%, the precision was 1.10%-2.30%, the standard recovery was 83.83%-100.02%, sampling efficiency was 100.00%. Conclusion: This method is fast, sensitive and accurate, and can be used for the determination of n-butylamine in the air of workplace.

NOx Emission Prediction of Diesel Vehicles in Deep Underground Mines Using Ensemble Methods

The mining industry faces persistent challenges related to hazardous gas emissions. Diesel engine-powered wheeled vehicles are commonly used during work shifts and are a primary source of nitrogen oxides (NOx) in underground mines. Despite diesel engine manufacturers providing gas generation data, mining companies need to predict NOx emissions from numerous load-haul-dumping (LHD) vehicles operating under dynamic conditions and not always equipped with gas sensors. This study focused on two ensemble methods: bootstrap aggregation (bagging) and least-square boosting (boosting) to predict NOx emissions. These approaches combine multiple weaker statistical models to yield a robust result. The innovation of this research is in the statistical analysis and selection of LHD vehicles’ working parameters, which are most suitable for NOx emission prediction; development of the procedure of source data cleaning and processing, model building and analyzing factors, which may influence the accuracy; and the comparison of two ensemble methods and showing their advantages and limitations for this specific engineering application, which was not previously reported in the literature. For datasets obtained from the same LHD vehicle and different operators, the more efficient bagging method gave a coefficient of determination R2 > 0.79 and the RMSE (root mean square error) was under 30 ppm, which is comparable with the measurement accuracy for transient regimes of physical NOx sensors available in the market. The obtained insights can be utilized as input for mine ventilation systems, enhancing mining transport management, reducing workplace air pollution, improving work planning, and enhancing personnel safety.

The method of determination for 2, 3-Butanedione in the air of workplace by high performance liquid chromatography with derivatization

Objective: To establish a method for the determination of 2, 3-Butanedione (BUT) in the air of workplace, which including the process of collection by absorption in phosphoric acid aqueous solution and the process of analysis and detection by high performance liquid chromatography with derivatization. Methods: In October 2022, a porous glass plate absorption tube containing 10 ml of 0.01% phosphoric acid solution was used to collect BUT in the air of the workplace at a flow rate of 0.2 L/min. The absorption solution was derived by 2, 4-dinitrophenylhydrazine for 75 min and separated on a SB-C18 column (250 mm×4.6 mm, 5 μm) . At the column temperature of 30 ℃, the mixture of acetonitrile-water (V∶V, 1∶1) was eluted at the flow rate of 1.0 ml/min. It was detected by UV detector (λ=365 nm) , qualitatived by retention time and quantitatived by external standard. Results: It showed that BUT in phosphoric acid aqueous solution could be stored for at least 7 d at 4 ℃. There was a linear relationship within the determination range of 0.05-6.00 μg/ml, the linear regression equation was y=89.610x+0.133, r=0.9999. The sampling absorption efficiencies were 98.33%-100.00%, the detection limit of the method was 0.005 μg/ml, the minimum detection concentration was 0.016 mg/m(3) (based on V(0)=3.0 L) . The recovery rates were 95.96%-102.44%, the intra batch precision were 4.36%-7.78%, and the inter batch precision were 4.96%-6.06%. Conclusion: The method has the advantages of simple operation, high sensitivity and good accuracy. It can prevent the loss and degradation of BUT. It can be used for the determination of BUT in the air of workplace.

The study on biological exposure index of occupational exposure to arsenic and its inorganic compounds

Objective: To establish biological exposure index (BEI) of occupational exposure to arsenic and its inorganic compounds through occupational epidemiology and the regression analysis of internal and external exposure of workers. Methods: In November 2021, 125 workers with occupational exposure to arsenic and its inorganic compounds and 49 office administrators in a non-ferrous metal smelter in Yunnan Province were selected as the exposure group and control group, respectively. Air samples from the workplace of the study subjects on weekdays were collected and arsenic concentrations were determined. Urine samples were collected in end-of-work weekend and high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was used to detect the levels of trivalent inorganic arsenic (iAs(3+)) , pentavalent inorganic arsenic (iAs(5+)) , monomethyl arsenic (MMA) and dimethyl arsenic (DMA) in urine. The correlations between arsenic concentration in the workplace air and arsenic species in urine of workers were analyzed. Arsenic exposure concentration and the level of urinary arsenic (ΣiAs+MMA+DMA) of workers was analyzed by linear regression and the BEI of arsenic and its inorganic compounds in the workplace was proposed based on the results of micronucleus test. Results: The median of time-weighted average concentration (C(TWA)) of arsenic in the workplace air of the exposure group was 0.0116 mg/m(3), and the over-standard rate was 71.2% (89/125) . The concentrations of iAs(3+), iAs(5+), inorganic arsenic (iAs=ΣiAs(3+)+iAs(5+)) 、MMA、DMA and urinary arsenic in the exposure group were higher than those in the control group at the end of shift, and the differences were statistically significant (P<0.05) . The concentration of arsenic in the workplace air had the strongest correlation with the concentration of urinary arsenic at the end of the shift (r(s)=0.909, P<0.001) . The regression equation was lg (y) =7.662+2.968lg (x) (r=0.821, P<0.05) . According to the occupational exposure limit (OEL) of arsenic in China, the concentration of urinary arsenic in the end-of-work weekend was calculated to be 53.2 μg/L. Combined with the results of micronucleus test, the BEI of occupational exposure to arsenic and its inorganic compounds in the workplace was proposed to be 50 μg/L. Conclusion: The urinary arsenic in the end-of-work weekend can be used as a biomarker of occupational exposure to arsenic, and its BEI is recommended to be 50 μg/L.

Occupational exposure to organotin substances: Development of a liquid chromatographic separation method for 11 organotin compounds in workplace air samples via HPLC-ICP-MS

Organotin compounds (OTCs) are widely regulated but rank among the most used organometallic compounds in various industrial sectors. They are significantly more toxic than inorganic tin compounds. At workplaces, OTCs can be released as vapors or dust particles and can be absorbed by inhalation or skin contact. Occupational exposure thus represents a great risk for the absorption of OTCs for employees. Methods for OTCs speciation in workplace air monitoring currently do not exist. This study describes the development of a separation method for eleven in Germany regulated OTCs via HPLC-ICP-MS. The method allows a near baseline separation of MMT, MBT, MOT, MPhT, DMT, DBT, DPhT, TMT, TBT, TPhT and TTMT within 22 min on a C18 column and a ternary solvent and flow rate gradient using methanol, acetonitrile, and ultrapure water + 6% (v/v) acetic acid + 0.17% (m/v) α-tropolone. Ten analytes show linearity in the working range of 10 - 100 µg OTCs/L with R² > 0.999. Due to its high volatility the analyte TTMT showed a quadratic relationship between concentration and signal intensity with R² = 0.9998. The determination of the instrumental limits resulted in detection limits between 0.14 and 0.57 µg Sn/L and limits of quantification between 0.49 and 1.97 µg Sn/L. Over the course of this study thermal instability and cross reactivity of OTC in solution became apparent. Formation of two reaction products in mixed OTCs solutions have been observed. These effects will further be examined within development of appropriate sampling and sample preparation for workplace air to provide a suitable method for the determination of OTCs at workplaces according to normative references.

Needle trap devices packed with an imine-based 2D COF: An innovative tool for the sampling of polycyclic aromatic hydrocarbons in air

This study introduces a new method for sampling and microextraction of polycyclic aromatic hydrocarbons (PAHs) in the air using needle trap devices (NTDs) packed with an imine-based covalent-organic framework (COF) as an adsorbent. The NTD was coupled with gas chromatography-flame ionization detection (GC-FID) for analytes’ separation and quantification. The COF adsorbent was synthesized using a solvothermal method at room temperature and packed inside a stainless-steel needle. The adsorbent was characterized using X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM-EDS) and Brunauer-Emmett-Teller (BET) analysis. The method was developed in the laboratory under various conditions and subsequently applied in the field to compare the results with those obtained using sampling and analytical method-NIOSH 5528. The desorption conditions and breakthrough volume (BtV) were optimized at recommended exposure limits concentration using response surface methodology (RSM) with a central composite design (CCD). Accordingly, the optimal values for desorption temperature and BtV were obtained 310 °C and 2840 mL, respectively. The limits of detection (LODs) and the limits of quantification (LOQs) were found to be 0.021–0.027 and 0.065–0.091 μg L−1, respectively. The repeatability and reproducibility of the method (R%) were estimated to be 4.02–6.83 % and 8.51–10.34 %, respectively. Also comparing the mean concentrations of the samples collected by the NTD and the NIOSH 5528 method, revealed no statistically significant differences between the methods (p > 0.05). Overall, the COF-packed NTD was identified as an appropriate and reliable method for sampling and extracting occupational and ambient contaminants in the workplace air.

Personal respirable dust and respirable crystalline silica exposure in two shafts and a concentrator of a Zambian copper mine.

Since the 1920s, Zambia's mining sector has experienced growth, which has increased the number of mine workers employed in the industry. Consequently, the potential for occupational exposure and prevalence of occupational diseases have also increased. Unfortunately, Zambia does not currently have legislative guidelines for workplace air monitoring and compliance. This study's objectives were to evaluate copper miners' personal exposure to respirable dust and respirable crystalline silica (RCS) and to assess workplace compliance using the European Standard for workplace air monitoring and measurement (EN689:2018). This cross-sectional study collected 100 personal respirable dust exposure samples at a Zambian copper mine in 2023. These samples were weighed using NIOSH method 0600 and analyzed for crystalline silica using Fourier transform infrared spectroscopy (KBr pellet) (NIOSH method 7602). Additionally, 253 respirable dust exposure measurements collected at the mine between 2017 and 2022 were included for comparison. The median respirable dust exposure for the 2023 exposure measurements was 0.200 mg/m3 (95th percentile 2.871 mg/m3) compared to 0.400 mg/m3 (95th percentile 3.050 mg/m3) for the historic data. The median RCS exposure was 0.012 mg/m3 (95th percentile 0.163 mg/m3). Using EN689:2018, it was found that from 15 work areas, only six work areas complied with the standard for respirable dust exposure and only seven work areas complied with the standard for RCS exposure. At the mining site, several work areas had substantial exposure to respirable dust and RCS. Therefore, management needs to prioritize these areas when implementing control measures to reduce dust exposure. For the Zambia mining industry to manage exposure to respirable dust and RCS, it is necessary to implement standardized monitoring strategies. This study has demonstrated that EN689:2018 can be used successfully to determine compliance among Zambian mining work areas.