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REACH – a new EU regulation that increases chemical safety
Kararzyna Miranowicz-Dzierżawska
The article presents assumption data and provisions of Regulation (EC) No. 1907/2006 of the European Parliament and of the Council of 18 December 2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), establishing a European Chemicals Agency, amending Directive 1999/45/EC and repealing Council Regulation (EEC) No 793/93 and Commission Regulation (EC) No 1488/94 as well as Council Directive 76/769/EEC and Commission Directives 91/155/EEC, 93/67/EEC, 93/105/EC and 2000/21/EC, which entered into force on 1 June 2007.
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Arsine
Daria Pakulska
Arsine is a highly poisonous, nonirritating and colorless gas. It is extensively used in the semiconductor industry and in manufacturing lead-acid storage batteries. Most cases of arsine poisoning result from the formation of arsine as a by-product during many chemical and metallurgical processes.
Acute arsine poisoning is known to result in massive damage of red blood cells. Rapid hemolysis may lead to oliguric renal failure and death. Symptoms of chronic poisoning are similar to those observed in acute poisoning. The proposed maximum exposure limit (MAC) for arsine in the air (0.02 mg/m³ ) is based on the value of (0.08 mg/m³ ) derived from a long-term inhalational administration study on mice. This value is similar to that determined by ACGIH (2007). This level of MAC for arsine prevents increased risk of hemolysis and hemolysis-related effects on the spleen, kidney and other organs. Considering that arsine does not possess irritating effects on the skin and mucous membranes, the Expert Group for Chemical Agents has not established a MAC (STEL) value.
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Chlorobenzene
Andrzej Starek
Chlorobenzene is a colorless liquid used as an organic solvent and an intermediate in organic synthesis. Data from environmental monitoring indicate that exposure to chlorobenzene does not exceed acceptable values.
Symptomatology of acute poisoning with chlorobenzene in human has not been described to date. Headaches and both upper respiratory tract and eye irritation have been reported in workers exposed to this chemical.
Acute oral and dermal toxicity of chlorobenzene in animals is low. This chemical exerts hepatotoxic, nephro-toxic and hematotoxic effects during acute and subchronic exposure. Chlorobenzene is not mutagenic though it has been shown to bind with liver, kidney and lung DNA, RNA, and proteins in rats and mice. There is no evidence of embryotoxic, fetotoxic, teratogenic and carcinogenic effects.
On the basis of the NOAEL value (230 mg/m³ ) obtained in a subchronic experiment in rats and the relevant uncertainty factors, a MAC (TWA) value of 27.3 mg/m³ was calculated. In accordance with European Commis-sion Directions the MAC (TWA) value of 23 mg/m³ has been suggested. On the basis of MAC (TWA), the MAC (STEL) value of 70 mg/m³ has been calculated.
Moreover, monitoring total (free and conjugated) 4-chlorocatechol in urine specimens collected at the beginning of a new shift and at the end of exposure or at the end of the shift with BEI values of 16 mg/g creatinine and 80,5 mg/g creatinine, respectively, is recommended.
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4-Methylpent-3-en-2-on
Krystyna Sitarek
4-Methylpent-3-en-2-on (mesityl oxide, MO) is a colorless to light yellow oily liquid. Its odor has been described as peppermint or honeylike. 4-Methylpent-3-en-2-on has been use as a solvent for cellulose resins, gums, rubbers cleaners, lacquers and varnishes, and as an inert in a herbicide. The acute oral LD50 is 1120 or 655 mg/kg for the rat and 923 mg/kg for the mouse. This substance produce irritation and transient corneal injury to the eye, and it is irritant of mucous membranes. Prolonged skin contact produce dermatitis. Sublethal concentrations of the vapors may result in vascular congestion, which has been reported to occur primarily in the kidneys. Respiratory depression to 50% of the normal frequency (RD50) in mouse was obtained at concentrations of 244 mg/m³ . 4-Methylpent-3-en-2-on is not mutagenic and reprotoxic agent. The number of litters produced by animals ex-posed at 125, 410 and 1200 mg/m3 during premating, mating, gestation and lactation phases was comparable to control animals. The proposed maximum exposure limit MAC (TWA) was calculated on the basis of the RD50 value of 244 mg/m³ . The Expert Group for Chemical Agents recommended a TWA 20 mg/m³ (10% RD50), STEL 40mg/m³ and “I” – irritant substance notation.
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Ethyl silicate
Andrzej Sapota
Ethyl silicate is a colorless liquid with a slightly perceptible odor. This compound finds numerous applications in a number of industrial branches, e.g.,paint and lacquer, chemical or pharmaceutical. It is also used as an agent to harden natural stone, terracotta, artificial marble, frescoes and clay as well as a water- and acid-resisting solvent applied in cement and masonry mortar in brick production. Ethyl silicate is well absorbed via respiratory and alimentary tracts, but its absorption through the skin is rather weak. In ethylsilicate-exposed workers, eye and nasal mucosa irritating properties of this compound have been observed. Data on chronic ethyl silicate effects in humans are not available in the literature. In laboratory animals, ethyl silicate’s acute toxicity, expressed in median lethal doses, is relatively low. ethyl silicate shows a mild irritating effect on rabbits’ eyes. There is no data on ethyl silicate’s chronic toxicity. In short-term, sub-chronic studies performed on mice and rats exposed to ethyl silicate through inhalation and after its administration in other ways, along with necrotic lesions in the olfactory epithelium of the nasal cavity, there were changes in the liver and kidneys. The latter comprised interstitial inflammation and necrotic lesions in renal tubules. Short-term exposure of laboratory animals to high ethyl silicate doses induced its toxic effect on the lungs (pulmonary edema, leukocyte infiltration, petechia in pulmonary alveoli, and bronchial tubes). Ethyl silicate’s mutagenic effect has not been revealed in the Ames test. No data on embryotoxic, phototoxic, and teratogenic effects of ethyl silicate are available in the literature. This compound has not been categorized by the International Agency for Research on Cancer (IARC) with respect to its potential carcinogenic risk.
The presented evidence shows that the major toxic effect of ethyl silicate at its high concentrations (over 2000 mg/m³ ) is eye and nasal mucosa irritation in humans, whereas the nephrotoxic effect and damage to the olfactory epithelium of the nasal cavity are observed in laboratory animals. On the basis of the nephrotoxic effect of ethyl silicate, its maximum allowable concentration (MAC) was calcu-lated. Inhalation exposure of rats, rabbits and guinea pigs to ethyl silicate at concentrations of 199, 432, and 760 mg/m³ for 90 days did not reveal any organic changes, which has made it possible to adopt the concentration of 760 mg/m³ as the value of no observed adverse effect level (NOAEL). Another experiment performed on rats exposed via inhalation to this compound at the concentration of 850 mg/m³ for 28 days revealed its nephrotoxic effect manifested by interstitial kidney inflammation and necrotic lesions in renal tubules After adopting relevant uncertainty coefficients and the concentration of 760 mg/m³ as the NOAEL value, the calculated MAC value for ethyl silicate is 95 mg/m³ .
In Poland, the binding MAC value for ethyl silicate is 80 mg/m³ , whereas in other countries of the European Union (EU) and in most outside the EU, MAC values are kept at the level of 85 – 87 mg/m³ . In view of the relatively small difference between the calculated value (95 mg/m³ ) and that binding to date, it is proposed to keep the MAC value at the present level, i.e., 80 mg/m³ . The proposed MAC value should protect workers against the potential systemic ethyl silicate effect. Bearing in mind the high threshold of its irritating effect on eyes and mucous membrane in humans, it should be assumed that the adopted MAC value will also be effective in this case. There are no grounds for adopting MAC (STEL) and BEI values for this compound.
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Propylene
Krystyna Sitarek
Propylene is a colorless, flammable gas. It is used in the production of manufactured plastics and fibres. Short-term exposure to propylene had no toxic effects on rats and mice. Non-neoplastic and inflammatory changes were found in the nasal cavities of rats, whereas mice showed chronic focal kidney inflammation. Propylene is not classifiable as to its carcinogenicity to human (group 3 IARC). Propylene in high concentrations in the air appeared to have acted primarily as a simple asphyxiant.
Numerical occupational exposure limits are recommended for propylene because available oxygen (min 18%) has been considered the limiting factor.
The Expert Group for Chemical Agents established an 8-hour TWA value of 2000 mg/m³ and STEL – 8600 mg/m³ .
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Sevoflurane
Małgorzata Kupaczewska-Dobecka
Sevoflurane (SVF) is a nonflammable and non-explosive liquid. It is a clear, colorless, nonpungent liquid. Sevoflurane is a polyfluorinated methyl isopropyl ether inhalation general anaesthetic with lower solubility in blood and body tissues than halothane. Sevoflurane has been demonstrated to be an appropriate agent for use in neurosurgery, caesaeran section, coronary artery bypass surgery and in non-cardiac patients at risk for myocardial ischaemia.
Like other potent inhalation anaesthetics, sevoflurane depresses respiratory function and blood pressure in a dose-related manner. Sevoflurane in concentration of 1-8% in, mixture with oxygene (83 000-664 000 mg/m³ ) produces anaesthesia in 2 minutes both in adults and children. The rapid pulmonary elimination of sevoflurane minimizes the amount of anaesthetic available for metabolism. In humans <5% of sevoflurane absorbed is metabolized to hexafluoroisopropanol with release of inorganic fluoride and carbondioxide.
An assessment of health risk from exposure to this inhalant anaesthetic poses a serious problem for the employers, mostly due to the fact that this compound belong to the category for which no Maximum Admissible Concentration has been established. Consequently, there is no obligation to measure their air concentration in workplace.
Based on additive action of anaesthetics, its minimum alveolar concentration values and data from experiments on human, the OEL value for sevoflurane has been proposed. Decrease of efficiency in behavioral and psychomotoric tests was observed in volunteers exposured on anesthetics. LOAEL of 354 mg/m³ has been estimated.
The MAC value of 55 mg/m³ for sevoflurane in assessment of workplace hazards has been proposed. This exposure level is to protect the surgical staff from adverse neurological, cardiovascular, respiratory and irritant effects.
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Toluene
Marek Jakubowski
Toluene is a clear, colorless liquid with a distinctive smell. The largest source of toluene release is during the production, transport and use of gasoline, which contains 5 ÷ 7% toluene by weight. Toluene is used in making paints, paint thinners, lacquers and adhesives.
Absorption of toluene results mainly from inhalation of its vapor. In human studies retention of toluene in the lungs has been estimated by different authors to be 60 ÷ 80%. Significant amounts may also be absorbed through the skin if there is contact with the liquid form. The rate of absorption through the skin amounts to about 0.69 mg/cm2/h. Following absorption, toluene is rapidly distributed, with the highest levels observed in adipose tissue followed by bone marrow, adrenals, kidneys, liver, brain and blood. A mean toluene half-life of toluene in blood amount to 4.5 h and to 3.8 h in alveolar air. Approximately 20% of the absorbed toluene is excreted unchanged in the expired air. A minute amount is excreted in urine. The reminder is oxidized by trans-formation of the methyl radical into the carboxyl radical, which is mainly conjugated with glycine to produce hippuric acis. Less than 1% of the dose is hydroxylated to cresols. Hippuric acid is excreted in urine with a bio-logical half-life of 3.5 h.
Adverse effects on the nervous system and respiratory tract irritation are the critical effects from inhalation exposure to toluene. Experimental exposure of human volunteers to toluene at about 375 mg/m³ did not produce statistically significant differences in the results of tests measuring psychometric performance and subjective evaluations of well-being when compared to controls (NOAEL). Spontaneous abortions were observed as result of occupational exposure to toluene in concentrations of 170 ÷ 550 mg/m³. Irritation of the nose and throat was reported in printers exposed to 375 mg/m³ of toluene for 6.5 h and in volunteers exposed to the same concentration of toluene for 6 h (LOAEL).
The proposed occupational exposure limits OEL-TWA of 100 mg/m³ and OEL-STEL of 200 mg/m³ are based on the LOAEL of 375 mg/m³ for irritative properties of toluene. As toluene is absorbed through the skin and is potentially fetotoxic the “Sk” and “Ft” symbols should denote this compound.
A BEI value of 0.5 mg of o-cresol in urine samples collected at the end of the workshift has been proposed.
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