Maximum Admissible Concentration Value Research Articles

Determination of phenyl(2-naphthyl)amine concentrations in the working environment air using HPLC-FLD technique

Phenyl(2-naphthyl)amine (FNA) is a flammable solid with a characteristic odor. FNA is used, among others, in the production of paints and dyes, and as an antioxidant in rubber processing, lubricant for automobile engines, in brake fluids, oils, etc. In the European Union, FNA is classified as a category 2 carcinogen. In Poland, the value of the maximum admissible concentration (MAC) for FNA is 0.02 mg/m3. The aim of this study was to develop a new method for the determination of FNA, which will allow for the determination of this substance in the working environment within the concentration range of 0.1-2 of MAC value. The method is based on the retention of FNA on a cellulose filter, recovery of the substance with methanol and analysis of the solution thus obtained using a high-performance liquid chromatograph with a fluorescence detector. The developed method enables the determination of FNA in the concentration range 2-40 μg/m3. The limit of detection (LOD) is 0.23 ng/l and the limit of quantification (LOQ) is 0.69 ng/l. The method complies with the requirements of the European Standard PN-EN 482 and can be used to determine FNA concentrations in the workplaces air. Med Pr. 2022;73(1):25-31.

2-Nitroanisole. Determining in workplace air with gas chromatography

2-Nitroanisole is a colourless or slightly yellowish liquid. This substance is mainly used in the production of o-anisidine (2-methoxyaniline), which is directly or indirectly used for the production of more than 100 azo dyes. 2-Nitroanisole may cause cancer to humans. The aim of this study was to develop a method for determining concentrations of 2-nitroanisole in workplace air in the range from 1/10 to 2 of maximum admissible concentration (MAC) values. The developed method is based on the adsorption of 2-nitroanisole on a silica gel, extraction with methanol and chromatographic analysis of the resulting solution. The tests were performed using a liquid chromatograph (HPLC) 1200 series of Agilent Technologies with a diode array detector (DAD). Determinations were performed using an Ultra C18 column (25 cm × 4.6 mm, dp = 5 µm). The procedure was validated according to Standard No. EN 482. The method can be used to determine 2-nitroanisole in workplace air in the concentration range from 0.16 to 3.2 mg/m3, i.e., from 1/10 to 2 MAC values. In that range, the obtained calibration curve was linear, as evidenced by the regression coefficient of 1. The overall accuracy of the method was about 5.3% and its relative total uncertainty was 23%. This method enables selective determination of 2-nitroanisole in workplace air in the presence of other compounds, such as methanol, o-anisidine, 3-nitroanisole, 4-nitroanisole and 1-chloro-2-nitrobenzene. The method for determining 2-nitroanisole has been recorded in the form of an analytical procedure (see Appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

2-Nitroanisole. Documentation of occupational exposure limits (OELs)

2-Nitroanisole is a colorless to yellowish liquid poorly soluble in water. It is used primarily to o-anisidine and o-dinisidine synthesis, which are precursors of azo dyes. 2-Nitroanisole has harmonized classification in the European Union: Carc. 1B 4 – carcinogenic, 1B category; H350 – may cause cancer after exposure trough the respiratory tract or skin; Acute Tox. 4 – acute toxicity 4; H302 – it acts adversely after swallowing. Occupational exposure to this compound occurs during its production and application. In Poland in 2016 203 workers were exposed to 2-nitroanisole. No data on 2-nitroanisole toxicity in humans were found in the available literature. In rodents 2-nitroanisole did not demonstrate large toxicity after administration in a single dose. In these animals repeatedly treated with this compound an increase in parenchymatous organ weights, decrease in body weight and also methemoglobinemia and hemolytic anemia were observed. 2-Nitroanisole was mutagenic in bacterial tests, induced gene mutations, chromosomal aberrations and sister chromatid exchange, and also damaged DNA (positive commet test). In rodents 2-nitroanisole induced both preneoplastic and neoplastic alterations mainly in urinary bladder, kidneys, and large intestine. The maximum admissible concentration (MAC) value for 2-nitroanisole has been calculated on the basis of the results of a short term experiment performed on rats. The critical effects observed were an increase in both liver and spleen weight and hemolytic anemia. On the basis of the NOEL value at the level of 8 mg/kg bw./day and uncertainty factors of 36, a MAC value at the level of 1.6 mg/m3 was obtained. On basis of literature data urinary bladder cancer risk associated with 1.6 mg/m3 concentration of 2-nitroanisole and a lifetime occupational exposure (40 years) was calculated at 2 × 10-3, which may be recognized as acceptable risk. The MAC has ”Carc. 1B” notation (carcinogenic substance, 1B category).

3,3′-Dimethoxybenzidine. Determination in workplace air

3,3′-Dimethoxybenzidine (DMOB) is a substance classified to a group of carcinogens. The recommended maximum admissible concentration (MAC) value for this substance in workplace air is 0.2 mg/m3. The aim of this study was to develop and validate a sensitive method for the determination of 3,3′-dimethoxybenzidine concentrations in workplace air in the range from 1/10 to 2 MAC values, in accordance with the requirements of the standard PN-EN 482. The method consists in passing the air that contains DMOB through a sulfuric acid-treated glass fiber filters, washing out the substance settled on the filter, using water and solution of sodium hydroxide, liquid-liquid extraction with toluene, replacing dissolvent with acetonitrile and analyzing the obtained solution. Studies were performed using high-performance liquid chromatography (HPLC) technique. An Agilent Technologies (Germany) liquid chromatograph, series 1200, with a fluorescence detector (FLD) was used in the experiment. In the test, an Ultra C18 column of dimensions: 250 x 4.6 mm, with a precolumn of dimensions: 10 x 4.0 mm (Restek, USA) was applied. Method is linear within the working range 1.08 µg/ml do 21.60 µg/ml, which is equivalent to air concentrations from 0.02 to 0.4 mg/m3 for a 54-L air sample. The analytical method described in this paper allows for selective determination of 3,3’-dimethoxybenzidine in the workplace air in the presence of 1,4-phenylenediamine, benzidine, aniline, 3,3’-dimethylbenzidine, 2-nitrotoluene, 3,3’-dichlorobenzidine and azobenzene. The method is characterized by good precision and accuracy and meets the criteria for the performance of procedures for the measurement of chemical agents, listed in EN 482. The method may be used for the assessment of occupational exposure to 3,3’-dimethoxybenzidine and the associated risk to workers’ health. The developed method of determining 3,3’-dimethoxybenzidine has been recorded as an analytical procedure (see appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

Studies on an efficient method for determining ethyl carbamate in the workplace air

In relation to the proposal to introduce an occupational exposure limit value for ethyl carbamate (EC) in Poland, a need to develop a sensitive method for determination of this carcinogenic substance in the workplace air was emerged. In the presented paper, a new method for its determination by high-performance liquid chromatography (HPLC) with fluorescence detector (FLD) is proposed. The method is based on the adsorption of EC on the cellulose filter, its extraction with water, further reaction of EC with 9-xanthydrol in acidic solution. Determination of the obtained EC derivative (N-xanthyl ethyl carbamate) was then conducted in a reverse-phase system with acetonitrile and water mobile phase at a flow rate of 1 mL/min on an Ultra C18 column of 250 mm by HPLC–FLD. Measurement range of 0.1–2 µg/m3 for a 1440 L of air sample was appropriate to the established maximum admissible concentration value of 1 µg/m3. The limit of detection is 0.142 ng/mL, and the limit of quantification is 0.426 ng/mL, respectively. The developed quantitative method makes it possible to determine ethyl carbamate in workplace air, which in turn allows determining exposure indicators and facilitates occupational risk assessment for the employees.

Occupational exposure to selected isocyanates in Polish industry.

Isocyanates constitute a group of highly reactive, low molecular weight chemicals used worldwide for polyurethane manufacturing. The occupational exposure to these compounds is a major cause of occupational asthma, thus it is very important to monitor their concentration in the workplace atmosphere. The aim of the study was to measure the concentration of 4,4'-methylenediphenyl diisocyanate (MDI; CAS 101-68-8), toluene-2,4-di-isocyanate (2,4-TDI; CAS 584-84-9), toluene-2,6-di-isocyanate (2,6-TDI; CAS 91-08-7) and hexamethylene di-isocyanate (HDI; CAS 822-06-0) in the work environment for evaluation of the occupational exposure to these compounds. Determination of concentrations of selected isocyanates was carried out in 21 manufacturing plants, during different industrial processes. The collected air samples (personal samples) were analyzed by means of the high-performance liquid chromatography (HPLC). The presented results represent the 1st data on the occupational exposure to isocyanates in Poland. This set of data is generally indicative of concentrations of analyzed isocyanates that are low and do not exceed the maximum admissible concentration (MAC) values in Poland. Elevated concentrations (above the MAC value) were found only for the TDI in the course of manufacturing of polyurethane foam blocks. Results of many studies show that low concentrations of isocyanates (particularly of low volatility like for example MDI) in the air cannot exclude the possibility of additional absorption of these compounds through skin. Taking into consideration all the uncertainties associated with the evaluation of the risk of exposure to isocyanates based solely on measurement of their levels in the air, it would seem that the simultaneous application of environmental and biological monitoring would only facilitate a reliable assessment of the occupational exposure risk.

Assessment of occupational exposure of medical personnel to inhalatory anesthetics in Poland

Despite common use of inhalatory anesthetics, such as nitrous oxide (N2O), halothane, sevoflurane, and the like, occupational exposure to these substances in operating theatres was not monitored in Poland until 2006. The situation changed when maximum admissible concentration (MAC) values for anesthetics used in Poland were established in 2005 for N2O, and in 2007 for sevoflurane, desflurane and isoflurane. The aim of this work was to assess occupational exposure in operating rooms on the basis of reliable and uniform analytical procedures. The method for the determination of all anesthetics used in Poland, i.e. nitrous oxide, sevoflurane, isoflurane, desflurane, and halothane, was developed and validated. The measurements were performed in 2006-2010 in 31 hospitals countrywide. The study covered 117 operating rooms; air samples were collected from the breathing zone of 146 anesthesiologists, and 154 nurses, mostly anaesthetic. The measurements were carried out during various surgical operations, mostly on adult patients but also in hospitals for children. Time weighted average concentrations of the anesthetics varied considerably, and the greatest differences were noted for N2O (0.1-1438.5 mg/m3); 40% of the results exceeded the MAC value. Only 3% of halothane, and 2% of sevoflurane concentrations exceeded the respective MAC values. Working in operating theatres is dangerous to the health of the operating staff. The coefficient of combined exposure to anesthesiologists under study exceeded the admissible value in 130 cases, which makes over 40% of the whole study population. Most of the excessive exposure values were noted for nitrous oxide.

Can product water footprints indicate the hydrological impact of primary production? – A case study of New Zealand kiwifruit

► We modelled the impact of NZ kiwifruit on the scarcity and quality of freshwater. ► We evaluated how this impact can be represented by water footprints. ► We found that kiwifruit production in NZ has little impact on both scarcity and quality of freshwater. ► Only the blue water footprint calculated with our Approach 1 indicated the impact of kiwifruit freshwater scarcity well. ► The grey water footprint addresses water quality and is sensitive to the background and maximum admissible concentration. Water footprints have been discussed as indicators for the influence of primary products on water scarcity and water quality. We assessed the impact of New Zealand kiwifruit on the scarcity and quality of freshwater resources and evaluated how the green-, blue- and grey-water footprints represented this impact. Water scarcity relates to the freshwater stored in soil and groundwater over a yearly timeframe. We found a negligible net change in soil water, as the freshwater in the soil is replenished every year by rain. The dynamics of freshwater in soil is indicated by the green-water footprint. Kiwifruit production has no impact on freshwater scarcity in soils, and we suggest, therefore, discarding the green-water footprint in this and similar studies. The groundwater recharge below kiwifruit orchards showed a large regional variation. A net depletion of groundwater resources occurs only in two kiwifruit growing regions, and only when the orchards are over-irrigated. The blue-water footprint indicates the status of the freshwater resources stored in the groundwater. We compared two different concepts. Our hydrologically based concept (Approach 1) quantifies the net change in the resources, whereas the Water Footprint Network (Approach 2) only accounts for the consumption. The blue-water footprint calculated by Approach 1 could explain 97% and by Approach 2 only 63% of the regional variation of net groundwater recharge below kiwifruit orchards. The values of the blue-water footprints are, on a regional average, about −500 L and 100 L per tray of kiwifruit with Approaches 1 and 2, respectively. According to Approach 1, a tray of kiwifruit delivers a net groundwater recharge of 500 L per tray, whereas according to Approach 2 the production of a tray of kiwifruit consumes 100 L of groundwater. Only Approach 1 contains all the hydrological processes making up the water balance that relates to groundwater. We assessed the impact of regional kiwifruit production on water quality by focusing on nitrate. The grey-water footprint indicates pollutant loading rates. On average, across all regions, the nitrate concentrations in the drainage water were well below the New Zealand drinking water standard of 11.3 mg/L NO 3 –N, but above the median concentration of all New Zealand groundwaters of 1.3 mg/L NO 3 –N. The annual nitrogen loads ranged across the regions from 3 to 15 kg NO 3 –N/ha. We found that the absolute values of the grey-water footprints are very sensitive to the choice of background and maximum admissible concentration value. We recommend that this information must always be given in addition to the grey-water footprint value. Overall, we conclude that the blue-water footprints derived by the hydrologically rational Approach 1, along with the grey-water footprinting metric, are a first step towards the quantification of the impact of agricultural production on the scarcity and quality of freshwater resources. These metrics would enable one to compare, on a product by product basis, the impact of production from different regions or countries. Some additional discussion would still be needed to enable evaluation of the inter-product comparison.

RD50Value as the Criterion for Setting Maximum Admissible Levels of Occupational Exposure to Irritants in Poland

The aim of this work is to analyse Maximum Admissible Concentration (MAC) values proposed for irritants by the Group of Experts for Chemical Agents in Poland, based on the RD50 value. In 1994–2004, MAC values for irritants based on the RD 50 value were set for 17 chemicals. For the purpose of the analysis, 1/10 RD 50,, 1/100 RD50 and the MAC/RD50 ratio were calculated. The determined MAC values are within the 0.01–0.09 RD50 range. The RD50 value is a good rough criterion to set MAC values for irritants and it makes it possible to estimate quickly admissible exposure levels. It has become clear that, in some cases, simple setting the MAC value for an irritant at the level of 0.03 RD 50 may be insufficient to determine precisely the possible hazardto workers’ health. Other available toxicological data, such as NOAEL (No-Observed-Adverse-Effect Level)and LOAEL (Lowest-Observed-Adverse-Effect Level), should always be considered as well.

Pesticides in groundwater in Britain

The maximum admissible concentration (MAC) stated by the Directive from the European Community is 0.1 μg 1‐1 for individual pesticides, and groundwaters with levels above this require treatment by law before being supplied for drinking purposes. However the 1980 Directive is the subject of debate due to its absence of a toxicological assessment. This paper discusses some of the arguments for setting MAC values for pesticides in drinking water. The pesticides that have been most frequently detected in groundwaters in England and Wales are the triazines namely simazine and atrazine. These pesticides are herbicides emanating from diffuse mainly non agricultural situations, for example weed control operations on industrial sites, railways and road edges. Although agricultural herbicides are used in much greater tonnages that the triazines, the former are only occasionally noted in groundwater samples.