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1,1-Dichloroethylene. Documentation
Danuta Ligocka
1,1-Dichloroethylene (vinylidene chliride) is a low temperature bioling liquid with a sweet scent. 1,1-Di-chloroethene is used as a chemical intermediate (usually with vinyl chloride) in production of thermopastic resins, lacquers, fibres for safety clothes, etc.
The rat oral LD50 was 1500 mg/kg. In human, acute toxicity of 1,1-dichloroethene ca. 16 000 mg/m³ was observed as a depression of CNS.
After an oral administration of 1,1-dichloroethylene some reversed adverse effects were observed in liver, kidneys and Clara cells.
After several years of occupational exposure to 1,1-dichloroethylene at the concentration of 200 ÷ 2300 mg/m³ no signs of toxicity in liver, kidneys nor lungs had been observed.
1,1-Dichloroethene was mutagenic only due to mebabolic activation.
In setting exposure limits, the results of a 18-months inhalation rats exposere were considered. Based on the NOAEL value for female rats (100 mg/m³) and the relevant uncertainty factors, a MAC (TWA) value has been calculated at 12.5 mg/m³.
No STEL value has been established.
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Fluorides. Documentation
Marek Jakubowski
Fluorides are defined as binary compounds or salts of fluorine and another element. The chief fluoride minerals are fluorspar (CaF2) and cryolite (Na3AlF6). The fluorides of alkali metals such as sodium fluo-ride are soluble in water. Those of alkaline earth such as calcium fluoride, are insoluble or sparingly so-luble in water. Inorganic fluorides find a variety of commercial uses.
Soluble fluoride compounds are readily absorbed from the lungs and gastrointestinal tract. Studies in humans and animals have found that 90 ÷ 96 % of an oral dose of soluble fluoride compounds is absorbed. Poorly soluble fluoride compounds, such as calcium fluoride do not appear to be well ab-sorbed.
Fumes, containing fluoride in concentrations above 10 mg/m³ were irritating. No effects were noted at levels below 2.5 mg/m³.
The largest concentration of fluoride in the body is found in calcified tissues. Fluoride deposition in bone occurs mainly in regions undergoing active ossification and calcification. The amount of fluoride taken up by bone is inversely related to age. The primary pathway for fluoride excretion is via the kidneys and urine (about 50%). To a lesser extent fluoride is also excreted in the feces, sweet, and saliva. Fluoride elimination after intermittent exposure is triphasic.
Marked evidence of skeletal fluorosis was reported in workers exposed to gaseous fluoride and fluoride dust in the pot rooms of the aluminium industry, in magnesium
foundry, in the process of crushing and refining of creolite. No changes in bone density were found in a group of workers exposed in concentrations of fluoride averaging 2.65 mg/m³, while such changes were detected in workers with exposures averaging 3.38 mg/m³. No bone structure changes were observed if fluoride concentrations in 24-hour urine specimens were lower than 5 mg/l. Pharmacokinetic studies indicate that such no-effect level in 24-hour urine specimens is most likely to be achieved if the fluoride concentration in end-of-shift specimens is 9 mg/l and in preshift specimens is 2 mg/l.
In general positive genotoxicity findings occurred at doses that are highly toxic to cells and whole ani-mals. Carcinogenic classification – IARC, group 3 – not classifiable as to carcinogenicity to humans; ACGIH – A4 – not classifiable as human carcinogen.
Occupational exposure limits ( TWA) amount in different countries from 0.6 mg/m³ to 2.5 mg/m³. The Expert Group recommended a OEL-TWA 2 mg/m³ and biological exposure index (BEI) of 9 mg/g creati-nine for the end-of-shift samples of urine and 3 mg/g creatinine for preshift samples of urine.
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Formaldehyde. Documentation
Małgorzata Kupczewska-Dobecka
Formaldehyde is a colourless gas with a pungent odour. Its widest use is in the production of resins with urea, phenol and melamine and, to a small extent, their derivatives. It is also used in the production of adhesives and binders for the wood, plastics, textiles, leather and related industries. Formaldehyde is used extensively as an intermediate in the manufacturing of industrial chemicals.
Formaldehyde causes local irritation, acute and chronic toxicity and has genotoxic and cytotoxic proper-ties. Vapors are highly irritating to the eye and the respiratory tract. Acute effects include nausea, head-aches, and difficult breathing. Formaldehyde can also induce or exacerbate asthma. Chronic exposure is associated with respiratory symptoms and eye, nose and throat irritation. Repeated exposure of skin to the liquid causes irritation and allergic dermatitis.
The most reliable data are obtained in controlled studies with volunteers. Twenty-one volunteers were examined over a 10-week period. Measurements were related to conjunctival redness, blinking frequency, nasal flow and resistance, pulmonary function and reaction times. Subjective assessments included discomfort; the influence of personality factors on subjective scoring was also evaluated. The authors concluded that eye irritation was the most sensitive parameter recorded, and that the no-observed-adverse-effect levels for subjective and objective eye irritation were 0.37 mg/m³ and 0.615 mg/m³ (0.3 and 0.5 ppm) respectively.
International Agency for Research on Cancer classified formaldehyde as carcinogenic to human to group 1. Three types of cancers were assessed: nasopharyngeal cancer, leukaemia and sinonasal cancer. There was sufficient evidence that formaldehyde causes nasopharyngeal cancer, strong but not sufficient evidence of leukaemia and limited evidence of sinonasal cancer. On the basis of the latest data the risk of nose cancer was assessed as 10-7 ÷ 10-8 for formaldehyde concentration of 0.37 mg/m³/40 years.
Maximum admissible concentration value of formaldehyde in the working environment in Poland has been established as 0.24 mg/m³ as a time weighed value and 0.48 mg/m³ as short-term based on the irritation effect. The verification of the MAC value of formaldehyde in the working environment is supposed to be adapted to European standards. Vacatio legis was established until 20 March 2008.
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2-Furaldehyde. Documentation
Małgorzata Kupczewska-Dobecka
2-Furaldehyde is a colorless, oily liquid that turns reddish brown on exposure to light and air. Its odor is close to like that of benzaldehyde. It has had a wide variety of uses, such as a solvent, an ingredient of phenolic resins, a chemical intermediate, weed killer, fungicide, and flavoring agent. 2-Furaldehyde is used in solvent extraction processes in the petroleum refining industry. Furfural is an irritant of the eyes, mucous membranes, and skin. Irritation of eye and respiratory tract in human organism during occupa-tional exposure to furfural vapor has been found in concentrations ranging 20 ÷ 64 mg/m³. Workers noted frequent nasal irritation as evidenced by stuffiness, dryness, or soreness, and occasional bloody nasal discharge, dryness of the mouth or throat. Furfural has a rather high acute toxicity in animals. The U.S. National Toxicology Program conducted a 2-year gavage study of furfural in which Fischer-344 male and female rats had received daily doses of 0, 30, or 60 mg/kg and B6C3F1 male and female mice received daily doses of 0, 50, 100, or 175 mg/kg. There was clear evidence of carcinogenic activity in male mice, some evidence of carcinogenic activity in female mice and male rats, and no evidence of carcinogenic activity of furfural in female rats. IARC has been classified 2-furaldehyde to group 3 as unclassifiable as to carcinogenicity in humans. In the European Union 2-furaldehyde has been classified as the substance which cause concern for human owing to possible carcinogenic effects but in respect of which the available information is not adequate for making a satisfactory assessment (category 3). Furfural was positive for the induction of chromosomal aberrations and sister-chromatid exchanges in cultured Chinese hamster ovary cells.
In the inhalation subchronic study on hamsters the concentration 80 mg/m3 was identified as the non-observed-adverse-effect level (NOAEL). The critical effect is irritation and the target organ is mucous membrane of the nose. Based on this data the Expert Group of Chemical Agent established the 8-hour TWA value of 10 mg/m³, and the STEL value of 25 mg/m³. Furfural is a substance for which biological exposure indices (BEIs) have been recommended: 250 mg 2-furanocarboxylic acid/g creatinine in urine collected in the end of the shift.
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Hexsan-2-one. Documentation
Renata Soćko, Sławomir Czerczak
Hexsan-2-one is a colorless, volatile liquid with a characteristic, pungent, acetone-like odor. Hexsan-2-one is a ketonic solvent used in a wide variety of materials, including paints, lacquers, ink thinners, nitrocellulose, glues, resins, oils, fats, waxes and in printing plasticized fabrics.
Acute intoxication of hexsan-2-one causes eye and upper respiratory tract irritation, coma, narcosis and death. Several investigators have reported peripheral and central distal axonopathy in animals exposed by inhalation to hexsan-2-one.
Chronic hexsan-2-one intoxication leads to neurologic disturbances with characteristic electrodiagnostic abnormalities. Muscle weakness and electromyographic abnormalities are predominantly distal. Sensory deficits are distal and limited to pain, touch and temperature discrimination, with occasional loss of vibration sense.
On the basis of literature data 204.85 mg/m³ has been accepted as a LOAEL and the MAC value of hexsan-2-one in Poland has been established at 10 mg/m³ with Sk symbols (substance absorbed through the skin).
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Acyclic hexane isomers. Documentation
Jadwiga A. Szymańska, Elżbieta Bruchajzer
Acyclic hexane isomers, other than n-hexane include 2-methylpropane, 3-methylpropane, 2,2-di-methylbutane and 2,3-dimethylbutane. Isomers of hexane (hexans) are present in organic solvents for vegetable oils, glues, coatings and paints. They are also compounds of gasoline and are used as interme-diates for chemicals.
In humans, inhalation exposure to hexane isomers causes eye and mucous membrane irritation. Applied locally they cause dermatitis. Orally administered hexane isomers cause slight nausea, vomiting, stomach pain and diarrhea. The effects of chronic toxicity on human are not known.
Little information is available on acute toxicity of hexane isomers in animals. Increased lacrimation is the only overt sign of toxicity. In chronic and subchronic studies of hexane isomers in animals of neurotoxic effects is not observed (in concentration 1760 ÷ 5280 mg/m³).
Hexans do not display mutagenic effects. There is no evidence of reproductive toxicity, teratogenicity or carcinogenicity.
Hexane isomers have low solubility in water, their respiratory absorption is also low. These compounds are rapidly metabolized (primarily by hydroxylation to alcohols) and eliminated.
Experimental data suggest that there is no basis for a verification of the MAC value (400 mg/m³) for hexane isomers. According to the irritant effects of hexane isomers, the MAC-STEL of 1200 mg/m³ is recommended. The “I” (irritation substances) notation has been proposed.
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