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Quantitative and qualitative assessment of harmful biological agents in the working environment
Małgorzata Gołofit-Szymczak, Anna Ławniczek-Wałczyk, Rafał L. Górny
Harmful biological agents are an important problem of occupational medicine and environmental health. If there is a suspicion that a particular group of workers is exposed to harmful biological agents, which can cause disease symptoms in this group, the validity of this assumption should be confirmed by detecting a factor in the working environment and determining the level of exposure, directly or indirectly determining the presence of a biological agent in the worker who is ill. To detect the presence of biological agents in the workplace and to determine the magnitude of exposure, it is most important to study the bioaerosols. Microbiological testing of settled dust samples, biological material from workers and process materials may also be relevant. On a global scale, there are no generally accepted criteria for assessing exposure to biological agents or generally accepted threshold limit values and methodological recommendations. In Poland, Standard PN-EN 13098 approved by the Polish Committee for Standardization (PKN) in 2002 (and replaced in 2007) "Workplace atmosphere. Guidelines for measurement of airborne microorganisms and endotoxin" determines the conditions of sampling workplace air in relation to microorganisms and bacterial endotoxins. This article reviews the existing literature on the subject of quantitative and qualitative methods of assessing harmful biological agents in the working environment.
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Aniline. Documentation
Andrzej Sapota, Małgorzata Skrzypińska-Gawrysiak
Aniline is an oily colorless liquid with a characteristic odor. It is classified as a substance that exerts toxic effects through inhalation, ingestion and skin. It can cause damage to the eyes and induce allergy by dermal contact.
Aniline is produced in large quantities. It is a precursor to obtain transient compounds used in various industrial branches. It is used to produce 4,4’-methylenedianiline, a precursor for obtaining polyurethane foams, and to produce compounds of the industrial rubbers, dyes, pesticides and pharmaceutics. Occupational exposure to aniline may occur during its production, further processing and distribution, during the aniline release in the form of a breakdown product of thermal degradation of plastics (e.g., foundry or industrial rubber vulcanization) and application of aniline-containing products (e.g., dyes).
Ambient air concentrations of aniline in work environments in different branches of industry do not exceed 3.6 mg/m³. According to the data of the Chief Sanitary Inspectorate (2010), workers in Poland are not exposed to aniline air concentrations exceeding the maximum allowable value of 5 mg/m³.
Acute toxic effects of the exposure to aniline are cyanosis, anemia with Heinz bodies in the blood, asthenia, mental disorder, seizure and dyspnea. Because much research has not con-firm the possibility of acute poisoning with aniline, opinions on chronic poisoning in industrial conditions are controversial; they rather mention the effects of multiple acute poisonings.
On the basis of the results of the animal studies on the aniline acute toxicity, similar symptoms (cyanosis, disorders of the central nervous system, aniline dose-dependent increase in MetHb and Heinz bodies in the blood) have been reported, regardless of the exposure route (per os or inhalation). Great interspecies differences in the sensitivity to aniline have also been observed.
The results of the subchronic and chronic inhalation or oral exposure of rats and mice to aniline were dose-dependent increase in the level of reticulocytes, MetHb and Heinz bodies in the blood, and in the symptoms of spleen damage.
In vitro tests in lower organisms (not mam-mals) proved that aniline has no ability to induce point mutations. Aniline induced chromosome aberrations in both in vitro and in vivo conditions. These effects were observed after exposure to aniline in relatively high concentrations. Aniline also increased the frequency of in vitro micronuclei production in somatic cells of mice and rats but only in doses inducing methemoglobinemia and other toxic effects. The results of in vitro and in vivo tests for DNA damage following aniline exposure are rather divergent, but the researchers can assume that the aniline ability to cause directly DNA damage is very limited.
Aniline carcinogenic action (spleen cancer) was observed in rats only after chronic expo-sure to high doses of this compound (≥72 mg/kg). This was limited to a single animal species and practically to one gender (males). The International Agency for Research on Cancer (IARC) categorized aniline according to its potential carcinogenic risk to group 3 as not classifiable as to its carcinogen-icity in humans. The European Union experts classified aniline as a carcinogenic substance (Carc. 2) and labeled with H351 (suspected of being carcinogenic), whilst SCOEL classified it into group C: genotoxic carcinogens with the possibility to define on the basis of the avail-able data a practical value of allowable concen-tration.
Aniline showed neither embriotoxic nor terato-genic effects in experimental animals. Neither effects on reproduction in doses not toxic to dams have been reported.
Aniline is absorbed very quickly from the gas-trointestinal tract and the lungs, and through the skin. The absorption from the animal gastrointestinal tract ranges from 56–90% or more, depending on the species.
Aniline vapor absorption from airways by humans at rest (volunteers) was 2÷11 mg/h at concentration of 5÷30 mg/m3 and retention of 91.3%. Aniline in the form of vapor is also ab-sorbed through the skin with velocity similar to the airway absorption. The absorption velocity increases with the increasing envi-ronmental temperature and humidity. Aniline in the liquid form is also efficiently absorbed through the skin.
On the basis of the results of animal studies, the highest aniline concentration was in the blood (in erythrocytes) and in the spleen, kidneys, liver, urinary bladder and alimentary tract. The spleen was the only organ in which no decrease in aniline concentration over time was observed. A repeated administration of the substance leads to the accumulation and covalent binding of 14C-aniline in erythrocytes and the spleen. Aniline readily crosses the blood-placental barrier.
Aniline is metabolized in the liver via three metabolic routes: N-acetylation, C-hydroxylation and N-hydroxylation. N-hydroxylation and C-hydro-xylation products coupled with sulfuric and/or glucuronic acid are excreted with urine. N-hydro-xylation has toxic effects, including methemoglobinemia. In all tested animal species urine was the main elimination route of aniline metabolites and/or aniline. Only 2% of the dose was ex-creted with feces.
The production of methemoglobin and aniline-induced erythrocyte toxicity have been recog-nized as critical toxic effects of aniline after its repeated administration. Interspecies differences in the amount of produced MetHb between experimental animals and humans and the determination of MAC values were based on the available human data.
Tolerable level for people of blood MetHb is 5%. At this MetHb concentration, no clinical symptoms of exposure to aniline were ob-served. The studies in a group of volunteers showed that an oral aniline dose of 35 mg/person caused a maximum 3.7% increase in MetHb concentration. The physiological level is about 1% of MetHb and the maximum level is 4.7%. The 35-mg dose was adopted as an allowable internal dose. The model calcula-tions were done, including a 90% retention of aniline (inhalation intake) and the human lung ventilation of 10 m³ during the 8-h work shift. Aniline intake by a person via inhalation and dermal routes may be the same.
An allowable 35-mg daily aniline dose (both inhalation and dermal intake) corresponds with the exposure to aniline air concentration of 1.9 mg/m³ for 8 h. This value has been suggested as the aniline MAC value. The standard was labeled with “Sk” indicating dermal absorption of the substance. Because of the effects of aniline on erythrocytes, methemoglobinemia and damage to spleen leading to carcinogenic lesions observed only in rats, the maximum allowable short-term level of the aniline was defined to prevent the production of MetHb in short-time exposure. According to the calculation method of max-imum allowable values in Poland, short-term level should range from 3.53÷5.49 mg/m³. Therefore, the concentration of 3.8 mg/m3 was proposed as the short-term level value for aniline.
An internal 35-mg dose of aniline corresponds with the velocity of p-aminophenol urinal excretion under 1.5 mg/h in a 2-h collection at the end of work shift (6÷8 h). The maximum allowable concentration in the biological ma-terial for aniline is 1.5 mg of p-aminophenol/h.
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3,4-Dichloroaniline. Documentation
Andrzej Sapota, Małgorzata Skrzypińska-Gawrysiak
3,4-Dichloroaniline (3,4-DCA) is a solid substance that appears as light-brown crystals or needles with a characteristic odor. It is classified as a toxic substance exerting toxic effects via inhalation, through the skin and by ingestion. 3,4-Dichloroaniline can cause damage to the eyes and induce allergy by dermal contact.
3,4-Dichloroaniline is produced in large quantities. In the European Union, it is produced and/or imported by seven chemical companies, operating in three countries. Almost the whole production of this substance is transformed into 3,4-dichlo-rophenyl- isocyanate, an initial compound for the production of phenylurea herbicides (propanil, diuron and linuron). The remaining amount is used in the production of azo disperse dyes for polyester fibers. In Poland, linuron is used in the form of five preparations, while the registration of diuron has expired and its application is no longer allowed (information provided by the National Institute of Hygiene).
3,4-Dichloroaniline is produced in closed systems so that occupational exposure to this compound occurs mainly when collecting and analysing samples, and when maintaining devices used in its production. 3,4-Dichloroaniline production and processing take place at an elevated temperature (about 90 oC). Inhalation of fumes or particles produced by gas phase condensation and dermal contact are possible routes of exposure to 3,4-dichloroaniline.
The recorded 3,4-dichloroaniline concentrations in workplace air do not exceed 0.07 mg/m³. The highest, but only temporary, concentration recorded is 0.57 mg/m³. In the available literature, there are no data on occupational exposure to 3,4-DCA in Poland, exposure-related clinical symptoms in humans or information on epidemiological studies.
The major toxic effect of 3,4-dichloroaniline is manifested by the production of methemoglobin (MetHb). Clinical symptoms of acute intoxication in animals are cyanosis, fatigue, dyspnea and muscle weakness. Diarrhea, reduced reflexes and paralysis of extremities have also been observed. During the autopsy of animals, no evident lesions in the internal organs have been found. Ne-phrotoxic and hepatotoxic effects as other consequences of 3,4-dichloroaniline exposure have also been observed.
The guinea pig maximisation test (Magnusson-Klingman method) revealed a positive result of an allergic reaction to 3,4-dichloroaniline in 75% of tested guinea pigs (15/20).
Subchronic exposure of rats and rabbits to 3,4-dichloroaniline via inhalation or dermal contact resulted in an increased level of MetHb and related symptoms of a damaged spleen.
In vitro tests for 3,4-dichloroaniline genotoxicity produced negative results for gene and chromosome mutations, slightly positive for sister chromatid exchange and positive for damage to mitotic spindle. In vivo micronuclear test produced negative results.
In the available literature, there are no data on 3,4-dichloroaniline carcinogenic effects in humans and animals or information on its effect on reproduction in humans. Studies on rats have revealed a harmful effect of this compound on the male reproductive system. A lower sperm count and poor quality of sperm have been found in males. Developmental toxicity studies showed that 3,4-di-chloroaniline, in doses not toxic to mothers, does not exert harmful effects on the fetus development.
There are quantitative data on 3,4-dichloroaniline absorption from the alimentary tract; however, there are no findings on its absorption via other routes. Based on the toxic effects (MetHb production, splenotoxicity) observed at both inhalation and dermal exposure, it may be inferred that this substance is also absorbed into the airways and through the skin. 3,4-Dichloroaniline is not accumulated in the body but it produces hemoglobin adducts.
After per os administration of 3,4-dichloroaniline to rats, 81% of the dose was excreted with urine and 26% with feces. The largest part of the dose was excreted during 24 h following its administration. After intragastrical administration of 3,4-dichloroaniline to rabbits, the presence of orto- and para-hydroxylated compounds was revealed in urine. In vitro studies showed the presence of the following 3,4-dichloroaniline metabolites: 2- and 6-hydroxy-3,4-dichloroaniline (C-hydroxylation products), N-hydroxy-3,4-dichloroaniline (N-hydroxy-lation product), N-(3,4-dichlorophenyl) acetamide and N-(3,4-dichlorophenyl) formamide (N-acetylation products).
The production of MetHb has been regarded as critical toxic effects of 3,4-dichloroaniline exposure. In an experiment of subchronic inhalation exposure to rats, 3,4-dichloroaniline concentration increased the MetHb level up to 1.6%, but without clinical symptoms it accounted for 45 mg/m3. This concentration has been adopted as the NOAEL value for 3,4-dichloroaniline.
After applying the coefficients of uncertainty (total value of 8), it was suggested to adopt the concentration of 5.6 mg/m³ as the maximum admissible concentration (MAC) value for this compound. It has also been recommended to mark this standard value with “Sk” – a substance absorbed through the skin, as well as with “A” – a substance with allergic effect, in view of these properties observed in the studies. Thus far, there has been no ground for defining the short-term exposure limit (STEL) or the biological exposure index (BEI) for 3,4-di-chloroaniline.
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Ethyl acetate. Documentation
Renata Soćko
Ethyl acetate is colourless, transparent liquid with a fruity odour. It is one of the most widely used solvents and extractants in various industrial applications.
Ethyl acetate is absorbed well by inhalation and rapidly hydrolyzed to ethanol and acetic acid, which are metabolized further. Its acute toxicity is very low.
The critical effect in human is irritation of the upper respiratory tract and eyes after exposure to concentrations of over 1468 mg/m³. In high, almost lethal concentrations, ethyl acetate is narcotic and causes lung damage. Daily application of ethyl acetate led to defatting of the skin and damage to the stratum corneum of tested persons. Studies of volunteers exposed to ethyl acetate showed its irritating effect on the eyes and airways after exposure to a concentration of 1468 mg/m3 (LOAEL).
Following the above data, the MAC value for ethyl acetate was established at 734 mg/m3 and the value of STEL at 1468 mg/m³. The proposed values of the hygienic standards should protect workers from harmful effects of ethyl acetate on their eyes, airways and nervous system. An additional notation for ethyl acetate: “I” – an irritant substance.
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Petroleum mineral oils. Documentation
Andrzej Starek
Petroleum mineral oils are vacuum distillation products of the crude oil residues obtained by distillation under normal pressure. In the processes of solvent-refined oils, catalytic hydrogenation or hydrocracking cause: reduction or elimination of paraffin, alkenes, polycyclic aromatic hydrocarbons (PAHs), sulphur, and also decolorization, deodorization, and improve stability of the final products.
Mineral oils are used in industry as lubricants, hydraulic medium, dielectrics, heat carriers, refrigeration liquids, grinding fluids, anticorrosive factors. They are also used as liquids in the textile industry, components of printing inks and softeners. Highlyrefined oils are components of cosmetic and some therapeutic agents; they are also used in food processing.
Mineral oils have been shown to have relatively low acute toxicity by all routes of exposure. However, inhalation and aspiration of oils and oil products have produced some adverse health outcomes. In both humans and laboratory animals exposed to mineral oils, the respiratory system is the target. The changes in this system, namely, lipid pneumonia, frequently connected with lipid granuloma, are caused by mineral oils used for therapeutic purposes or by occupational exposure to oil mists. In the latter instance, the inflammatory changes in the lungs are caused by irritation effects of oil mists. In humans, respiratory changes of the obstruction type have also been observed. Highly-refined oils not containing PAHs or at the low levels of these compounds are not mutagenic.
The IARC classified highly-refined mineral oils as group 3 of carcinogenic compounds (sub-stances cannot be classified in terms of its car-cinogenicity to humans). On the other hand, there is sufficient evidence for carcinogenicity to humans and to animals for untreated (unre-fined) and mildly-treated (mildly-refined) oils, which are classified as group 1. Existing data are not sufficient to assess reproductive and developmental toxicity of mineral oils.
The maximum admissible concentration (MAC) for respiratory fraction of highly-refined mineral oils faction was calculated on the basis of the results of experimental studies on rats, in which adverse effects in the respiratory system were observed; they were expressed in inflammatory changes (inflammatory focuses), an increase in wet lung mass and dry-to-wet lung mass ratio, and also an elevated number of alveolar foam cells. Based on the NOAEL value of 50 mg/m³ and appropriate uncertainty factors, a MAC (TWA) value was calculated at 6.25 mg/m³. Maintaining the existing MAC value of 5.0 mg/m³ for mineral oils as an inhalable faction was proposed in Poland. No STEL (15 mins) and BEI values have been proposed.
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Calcium oxide. Documentation
Małgorzata Kupczewska-Dobecka
Calcium oxide (CaO, quick lime, unslaked lime) is an inorganic, white powder. Calcium oxide is used in the production of iron and steel, glass, calcium carbide, aerated concrete, for soil stabilization and thermochemical reaction with industrial waste. About half of the CaO production is used for preparing Ca(OH)2. Calcium oxide is produced by about 97 manufacturers in the EU; in Poland mainly by Lhoist.
Calcium oxide dust irritates the eyes and upper respiratory tract. The irritant effects are probably due primarily to its alkalinity, but dehydrating and thermal effects can also be contributing factors. Mixtures of CaO and water are highly alkaline; the pH value, depending of the concentration, is about 12–13. Calcium oxide reacts with water on the exter-nal surfaces of the body and is converted to calcium hydroxide, which liberates OH- ions. Ingestion of CaO causes burns of the esopha-gus and stomach. Particles of calcium oxide cause severe burns of the eyes. Repeated or prolonged contact with skin may cause der-matitis. Based on studies of people occupationally exposed to dust of calcium oxide, there was no reduction in performance spirometry lung at a concentration of 1 mg/m³ (range 0.4–5.8 mg/m³). Effects of CaO in con-centrations of 1–5 mg/m³ (the mass median aerodynamic diameter +/-SD was 6.53 +/-0.76) were studied in 12 lightly exercising men breathing through the nose. The parameters studied included nasal resistance, nasal secretion, mucociliary transport time and chemesthetic magnitude (irritation, pungency, piquancy, cooling and burning). The level of 2.5 mg/m³ can be considered as the LOAEL.
The Interdepartmental Commission recom-mended the following occupational limit values for calcium oxide: MAC 1 mg/m³ for respirable fraction and 2 mg/m³ for inhalable fraction and STEL 4 mg/m³ for respirable fraction and 6 mg/m³ for inhalable fraction.
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A method for testing the impact of nanoparticles on the surface properties of monolayer of a pulmonary surfactant major component (DPPC) in a Langmuir-Wilhelmy balance system
Dorota Kondej, Tomasz R. Sosnowski
This method is used to study the influence of particles of nanopowders on the surface properties of the main component of the pulmonary surfactant - dipalmitoylphosphatidylcholine (DPPC). The study consists in determining the changes in the surface pressure during the compression of DPPC monolayer formed on a surface of a suspension of the particles in saline. The assessment of the impact of nanoparticles on the surface properties of DPPC monolayer is carried out on the basis of the analysis of the compression isotherm of monolayer formed on the surface of a pure liquid phase and the compression isotherms of monolayer formed on the surface of the suspensions of various concentrations of nanoparticles.
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Nitropropane. Determination in the workplace air with gas chromatography
Anna Jeżewska
A new procedure has been developed for the assay of 1-nitropropane and 2-nitropropane with gas chromatography with a flame ionization detector. This method is based on the adsorption of nitropropane vapors on Carbosieve S-III, desorption with chloroform and chromatographic analysis of the obtained solution. The working range is 3 to 60 mg/m³ for a 12-L air sample and 0.3 to 6 mg/m³ for a 120-L air sample. The developed method of determining 1-nitropropane and 2-nitropropane has been recorded as an analytical procedure, which is available in the Appendix.
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Skin protection measures protecting against organic substances
Joanna Kurpiewska, Jolanta Liwkowicz
Skin protection measures are very helpful in prevention of occupational dermatoses. This study discusses the influence of organic substances on human skin and barriers protecting against these irritating effects. This study also present tests of the effectiveness of five skin protection products with technical methods. Barrier properties of these products differ significantly. Presented test methods are very helpful in selecting product with the best protective properties and barrier creams from care creams.
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