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3-Amino-1,2,4-triazole. Documentation
Paweł Struciński
3-Amino-1,2,4-triazole (amitrole) is a nonselective systemic triazole herbicide and plant growth regulator. Currently, the compound is not manufactured in Poland.
Amitrol has effects on several biological systems but of most significance is its goitrogenic activity. It selectively inhibits thyroid peroxidase, which prevents the binding of inorganic iodine to tyrosine and reduces synthesis of thyroid hormones. It subsequently causes increased release of TSH, which continually stimulates growth of the thyroid gland.
Amitrole has a very low toxicity to humans and laboratory animals. Studies have reported oral LD50 as high as 25000 mg/kg b.w., and the dermal LD50 as 15 mg/kg b.w.
In 11- and 13-week feeding experiments on rats, the lowest dose which had not affected the activity of thyroid gland was equal to 0.5 mg/kg of diet, and the assessed NOAEL value was 0.04 mg/kg b.w./day.
Most assays have shown that amitrole does not elicit mutagenic action. In mouse and rat experiments, amitrole administered orally induced thyroid follicular-cell adenomas and carcinomas by a non-genotoxic mechanism involving altering the thyroid hormones homeostasis. The hepatocellular tumours seen in mice and a marginal increase in the incidence of benign pituitary adenomas in mice, were also produced by non-genotoxic mechanisms. In 2001, the International Agency for Research on Cancer reclassified amitrole from group 2B to group 3.
The fetotoxic activity of amitrole was shown only in high, maternally toxic doses. It does not impair reproductive performance nor does it cause teratogenic malformations.
The recommended maximum exposure limit (MAC) for amitrole of 0.15 mg/m³ is based on NOAEL (0.04 mg/kg b.w./day) derived from subchronic feeding studies in rats and relevant uncertainty factors. No STEL and BEI have been proposed.
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2-Ethylhexyl nitrate. Documentation
Małgorzata Gołofit-Szymczak
2-Ethylhexyl nitrate (2-EHN) is a clear, pale yellow liquid with a characteristic hydrocarbon odour. 2-EHN is mainly used in the petrochemical industry to increase the cetane number and the hexadecane value of diesel oil. The major routes for occupational exposure to 2-EHN are dermal and inhalation.
The effects of 2-EHN on human, after repeated or chronic exposure, are headache or dizziness, chest discomfort or palpitations or nausea. The DL50 value, following oral administration in a rat, is 2000 mg/kg for 9640 mg/kg body weight and 4820 mg/kg after dermal treatment. The value of CL50 for a rat exposed for 4 hours is 14000 mg/m³. No mutagenic effects have been found in relevant experimental studies. There are no scientific data indicating carcinogenic and teratogenic toxicity of 2-EHN. The Expert Group has established a TLV value for 2-ethylhexyl nitrate of 3.5 mg/m³ and a STEL value of 7 mg/m³.
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2-Ethyl-1-hexanol. Documentation
Małgorzata Gołofit-Szymczak
2-Ethyl-1-hexanol (EH) is a colourless liquid with a mild, sweet odour slightly reminiscent of roses. EH is mainly used in the production of low volatility esters, nitrocellulose, paint, lacquer, rubber and paper. Occupational exposure to 2-ethyl-1-hexanol through inhalation or dermal contact occurs mostly at production of PVC plasticizer. EH can cause depression of the central nervous system, nausea, vomiting, diarrhoea, cough and dyspnea. The vapour or liquid can cause irritation of the skin, eyes, nose and throat.
The effects of EH on human, after repeated or chronic exposure, are irritation of the upper respiratory tract, skin and eye allergic reactions. The liver, kidneys, central nervous system, mucous membrane of respiratory and digestive tracts are critical organs for toxic action of 2-ethyl-1-hexanol in rats and mice. No mutagenic, carcinogenic and teratogenic effects have been found in relevant experimental studies. The Expert Group has established a TLV value for 2-ethyl-1-hexanol of 160 mg/m³, a STEL value of 320 mg/m³ and an “I” notation – irritation substance.
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Cyclohexyl isocyanate. Documentation
Jolanta Skowroń
Cyclohexyl isocyanate (CHI) is a colourless to pale yellow liquid. It is a lachrymator. It is used as a chemical intermediate in the production of drugs, pesticides, amines, ureas and other carbamoyl compounds. The vapour phases of cyclohexyl isocyanate are strongly irritating to the eyes, the skin and mucous membranes. Typical symptoms include breathlessness, dry cough, difficulty in breathing and possibly coughing up blood. Like other isocyanates, CHI may cause skin and respiratory sensitization. Symptoms may appear immediately or may be delayed several hours after exposure, depending upon the concentration, and may continue for 3 to 7 days or longer. Permanent lung damage may result. There are currently no reports of these effects in people working with CHI.
Cyclohexyl isocyanate is harmful by oral route for laboratory animals. The LD50 for rats is about 560 mg/kg. The vapours of cyclohexyl isocyanate are irritating to the respiratory tract and exert a depressive effect on the central nervous system in animals.
Due to the similarity of CHI to other isocyanates, the Expert Group has established 0.04 mg/m³ as a maximum exposure limit (MAC). There are no bases for establishing MAC-STEL and BEI values. According to the irritant and sensitized effect of cyclohexyl isocyanate, the Group has suggested an additional determination with letters I and A.
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Nitric oxide. Documentation
Andrzej Starek
Nitric oxide (NO) is a colorless gas with a pungent odor. The human olfactory threshold is 0.37-1.24 mg/m³. NO is a product of combustion processes. It is used mainly in the production of nitric acid and nitrosylcarbonyl compounds.
NO produces methemoglobin and nitrosyl-hemoglobin in the blood and it also induces mutations. This compound is five times less toxic than nitrogen dioxide.
The proposed maximum admissible concentration (MAC) – 3.5 mg/m³ and the MAC-STEL – 7.0 mg/m³ are based on the assumption that NO toxicity is five times lower than that of nitrogen dioxide.
Di(2-ethylhexyl)adipate – determination method – determination method
Anna Jeżewska
This method is based on the deposition of di(2-ethylhexyl)adipate aerosols on a PTFE filter, extraction with methanol and a gas chromatographic (GC-FID) analysis of the obtained solution.
The determination limit of the method is 40 mg/m³.
Allyl chloride – determination method – determination method
Joanna Kowalska
This determination method is based on the adsorption of allyl chloride vapours on activated charcoal (200/50 mg sections), desorption with N,N-dimethylformamide and a gas chromatographic with flame ionization detection (GC-FID) analysis of the resulting solution.
The determination limit of the method is 0.2 mg/m³.
2-Imidazolidinethione – determination method
Ewa Kozieł
Air samples were collected by drawing a known volume of air through glass filters. The filters were transferred into vials and the substance was extracted with 3 ml of water. The obtained extracts were analyzed with high performance liquid chromatography with ultraviolet detection.
The determination limit of the method is 0.01 mg/m³.
Hexanal – determination method – determination method
Anna Jeżewska
This method is based on the chemisorption of hexanal on a filter with a glass fibre coated with 2,4-dinitrophenylhydrazine, extraction of 2,4-dinitrophenylhydrazone of hexanal with acetonitrile and determination of the obtained solution with HPLC chromatography.
The determination limit of the method is 4 mg/m³.
2-Methylnaphthalene – determination method – determination method
Anna Jeżewska
The method is based on the adsorption of 2-methylnaphthalene vapours on resine XAD-2 and desorption with 1 mL of carbon disulfide. The obtained solution is analyzed by gas chromatographic (GC-FID).
The determination limit of the method is 2,5 mg/m³.
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