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Environmental and Health Assessment of Substances in Household Detergents and Cosmetic Detergent Products 11. Solvents
11.1 EthanolEcotoxicology Ethanol (CAS No. 64-17-5) is rapidly biodegraded in aerobic and anoxic environments like activated sludge, waste water, sediments, and soil. BOD5 values range from 37 to 86% ThOD. The biodegradability of ethanol has been determined to 74 and 84% removal of DOC during 5 and 20 days, respectively (IUCLID 2000). The low log Kow value (-0.32) indicates that ethanol will not bioconcentrate in aquatic organisms. The toxicity of ethanol towards aquatic organisms is very low with EC/LC50 values > 1,000 mg/l (IUCLID 2000). Human health Occupational exposure includes inhalation and dermal exposure. Inhalational exposure at the occupational limit value of 1,900 mg/m3 will not produce significant blood alcohol concentrations. The maximal concentration of ethanol in the blood for a 70 kg hard working person is 20 mg ethanol/l blood, when the air concentration is 1,900 mg/m3. In comparison, ingestion of a single drink will after 20-30 minutes give rise to a maximal concentration of 150-200 mg/l blood (Campbell and Wilson 1986). Ethanol is only absorbed in negligible amounts through skin. Ethanol precipitates protein. Briefly applied to the skin ethanol does no damage, but it is irritating if left on for long periods of time. Applied to wounds or raw surfaces it not only increases the injury but also forms a coagulum under which bacteria may subsequently thrive. It is thus not used to disinfect open wounds (Goodman et al. 1980). Classification Ethanol is not classifiable as pertains to health hazards. Ethanol is included in Annex 1 of list of dangerous substances of Council Directive 67/548/EEC and classified as Highly flammable (F) with the risk phrase R11 (Highly flammable). 11.2 Isopropanol (propan-2-ol)Ecotoxicology Isopropanol (CAS No. 67-63-0) is rapidly biodegraded in ready biodegradability tests (OECD 301E) with 95% DOC removal during 21 days and in a coupled unit test (OECD 303A) with 99.9% degradation during 3 hours. Under anoxic conditions isopropanol is first oxidized to acetone and hydrogen, after which acetone is fermented to methane and CO2. The removal of isopropanol was in the range of 69-74% in 20-40 days in a test using concentrated anaerobic waste as inoculum (IUCLID 2000). The low log Kow value (0.05) indicates that isopropanol will not bioconcentrate in aquatic organisms. The toxicity of isopropanol towards aquatic organisms is very low with EC/LC50 values > 1,000 mg/l (IUCLID 2000). Human health Occupational exposure includes inhalation and dermal exposure. Isopropanol is about twice as toxic as ethanol, although it generally has a low acute toxicity as measured by its oral rat LD50 of 5,045 mg/kg. It increases the toxicity of chlorinated solvents if exposure occurs simultaneously (HSDB 1999). Inhalation of high concentrations may give central nervous system depression, however reversible upon cessation of exposure. It does not produce adverse effects on reproduction; is neither a teratogen, a selective developmental toxicant, nor a developmental neurotoxicant; and it is not genotoxic or an animal carcinogen. The metabolism of isopropanol appears equivalent across species with rapid conversion to acetone and carbon dioxide (Kapp et al. 1996). Isopropanol can be absorbed through skin. Since isopropanol has greater fat-solvent effects than ethanol, repeated use has a drying effect on skin. Isopropanol is not an irritant. Severe cases of allergic contact dermatitis have been reported, but they are rare (HSDB 1999). Classifcation Isopropanol is included in Annex 1 of list of dangerous substances of Council Directive 67/548/EEC and classified as Highly flammable (F) with the risk phrase R11 (Highly flammable) and Irritant (Xi) with the risk phrases R36 (Irritating to eyes) and R67 (Vapours may cause drowsiness and dizziness). The Danish occupational exposure limit is 490 mg/m3 (Arbejdstilsynet 2000). 11.3 2-Butoxy ethanol (butyl glycol)Ecotoxicology 2-Butoxy ethanol (CAS No. 111-76-2) is rapidly biodegraded in ready biodegradability tests (OECD 301E) with 95% DOC removal during 28 days (IUCLID 2000). The low log Kow value (0.74) indicates that 2-butoxy ethanol will not bioconcentrate in aquatic organisms. The toxicity of 2-butoxy ethanol towards aquatic organisms is very low with EC/LC50 values > 500 mg/l (IUCLID 2000). Human health The lethal dose of ethylene glycols in humans is approximately 1.4 ml/kg, which would be equivalent to approximately 100 ml for a 70 kg person. The oral rat LD50 is 1.48 g/kg (HSDB 1999). Exposure to high concentrations of vapors, probably in the range of 300-600 ppm for several hours, would be expected to cause respiratory and eye irritation, central nervous system depression and damage to kidney and liver (HSDB 1999). The Danish occupational threshold limit value is 20 ppm (Arbejdstilsynet 2000). 2-Butoxyethanol penetrates the skin readily and the toxic action from excessive skin exposure may be more likely than from vapor inhalation. The rate of absorption through human skin is about 0.2 mg/cm2/h (HSDB 1999). Classification Butyl glycol is included in Annex 1 of list of dangerous substances of Council Directive 67/548/EEC and classified as Harmful (Xn) with the risk phrase R20/21/22 (Harmful by inhalation, in contact with skin and if swallowed) and Irritant (Xi) with the risk phrase R37 (Irritating to respiratory system). 11.4 1-DecanolEcotoxicoligy The aerobic biodegradability of 1-decanol (CAS No. 112-30-1) is reported to 86% ThOD during 30 days in a closed bottle test (OECD 301D). The relatively high log Kow value (4.23) indicates that 1-decanol has the potential to bioconcentrate in aquatic organisms. The toxicity of 1-decanol has been determined towards crustaceans and fish (Table 11.1). Table 11.1
ubstance has a low vapor pressure, 0.00851 mm Hg at 25° C, meaning that under normal conditions hazardous vapor concentrations will not build up. The substance has been tested for developmental toxicity by inhalation in rats with negative results (Nelson et al. 1990). Classification 1-Decanol is not included in Annex 1 of list of dangerous substances of Council Directive 67/548/EEC. 11.5 Butoxy diglycolEcotoxicology Butoxy diglycol (CAS No. 112-34-5) is readily biodegradable as more than 60% ThOD was attained during 28 days in the MITI (I) test (OECD 301C) (IUCLID 2000). The low log Kow value (0.15-0.91) indicates that butoxy diglycol will not bioconcentrate in aquatic organisms. The toxicity of butoxy diglycol towards aquatic organisms is very low with EC/LC50 values > 1,000 mg/l (IUCLID 2000). Human health The substance is of low acute toxicity as measured by its oral rat LD50 of app. 6 g/kg (HSDB 1999; RTECS 1999). It is of low acute toxicity by inhalation, but repeated dosage may cause lesions of the kidney. Though slightly irritating to the skin with prolonged contact it is only toxic by this route in large amounts and with continuous and prolonged contact. Butoxy diglycol has been tested by the dermal route for subchronic and reproductive toxicity in rats with negative results in doses as high as 2 g/kg/day. The substance produced dermal irritation which was dependent on concentration in incidence, severity, and time of onset, and more severe in females than in males (Auletta et al. 1991). Classification Butoxy diglycol is not included in Annex 1 of list of dangerous substances of Council Directive 67/548/EEC. 11.6 Propylene glycolEcotoxicology Propylene glycol (CAS No. 57-55-6) is rapidly degraded by microorganisms and 100% biodegradability during 24 hours has been observed in an aerobic biodegradability test with activated sludge. Several studies have shown that propylene glycol is also rapidly degraded under anoxic conditions in sludge as, e.g., 100% biodegradation was observed during 9 days (IUCLID 2000). The low log Kow value ( –0.92) indicates that propylene glycol will not bioconcentrate in aquatic organisms. The toxicity of propylene glycol towards aquatic organisms is very low with EC/LC50 values > 1,000 mg/l (IUCLID 2000). Human health The toxicity of the substance is low, both in experimental animals and in man. Propylene glycol is metabolized to lactic acid, a substance which is normally occurring in the body. No indications on mutagenicity or carcinogenicity have been found. Subcutaneous injections in mice led to a small increase in fetal malformations, but experiments with oral exposure of mice over several generations did not show any effects of toxicity to reproduction. Propylene glycol is mildly to moderately irritating to skin in concentrations above 10%. No irritation was seen in rabbit eyes. Several cases of allergy have been described, and concentrations above 10%, particularly if occluded, may give rise to allergic skin reactions. With skin affected by disease or damage the risk of irritation and allergic reaction is increased. Reactions have been described by 2% on eczematous skin. As propylene glycol is widely used, allergy cases are considered unusual. Propylene glycol may be absorbed through skin and increase the absorption of other substances (Roberts and Walters 1998; LaKind et al. 1999). CIR (1994) estimates that propylene glycol may be safely used in cosmetic preparations in concentrations up to 50%. Classification Propylene glycol is not included in Annex 1 of list of dangerous substances of Council Directive 67/548/EEC. 11.7 GlycerolEcotoxicology Glycerol (CAS No. 56-81-5) is readily biodegradable as 63% ThOD was attained during 14 days in the MITI test (OECD 301C), whereas 93% ThOD was reached during 30 days in the closed bottle test (OECD 301D). Inherent anaerobic biodegradability of glycerol was confirmed in an acetate-enriched bacterial culture from digested domestic sludge as 90% degradation was observed during 8 days (IUCLID 2000). The low log Kow value (-2.56) indicates that glycerol will not bioconcentrate in aquatic organisms. The toxicity of glycerol towards aquatic algae, invertebrates and fish is very low, with EC50 values > 1,000 mg/l (IUCLID 2000). Human health The adverse effects of glycerol are due to the dehydrating effects of the substance. Pure glycerol may irritate the skin. Contact with the eyes will give strong irritation and pain. Glycerol may damage the endothelial cell of the cornea of the eye because of the osmotic effect – the eye is dried out, so to speak (Grant and Schuman 1993). Sensitization is very rare (Fisher 1986). Classification Glycerol is not included in Annex 1 of list of dangerous substances of Council Directive 67/548/EEC. 11.8 2-Amino ethanolEcotoxicology 2-Amino ethanol (CAS No. 141-43-5) is rapidly biodegraded in ready biodegradability tests as > 95% DOC removal was seen after 4 days in the DOC die away test (OECD 301A), whereas > 80 ThCO2 was reached during 19 days in the CO2 evolution test (OECD 301 B) (IUCLID 2000). The low log Kow value (-1.91) indicates that 2-amino ethanol will not bioconcentrate in aquatic organisms. The toxicity of 2-amino ethanol towards aquatic invertebrates and fish is low with EC50 values > 100 mg/l (IUCLID 2000). Human health The substance reacts as a base in aqueous solution, and the pH of 0.1N 2-amino ethanol is approximately 12. The nitrosation of the ethanol amines may result in the formation of N-nitrosodiethanolamine (NDELA) which is carcinogenic in laboratory animals. 2-amino ethanol can react with an aldehyde to form DEA, and then can be nitrosated to form NDELA. The optimum pH for nitrosamine formation is variously reported to be between 1 and 6. However, in the presence of catalysts such as chloral or an aldehyde, nitrosation reactions may occur up to a pH of 11 (CIR 1994). Weeks et al. 1960 reported that the dominant effects of continuous exposure of dogs, guinea pigs, and rats to 5-6 ppm 2-amino ethanol vapor were skin irritating and lethargy. The inhalation of 2-amino ethanol vapor at concentrations of 12-26 ppm for 90 days did not result in any mortality in dogs or rodents. Some deaths did occur after 25 days in dogs exposed to 102 ppm 2-amino ethanol vapor, and after 24-28 days in rodents exposed to 66-75 ppm 2-amino ethanol vapor. Exposure to 66-102 ppm 2-amino ethanol vapor caused behavioral changes and produced pulmonary and hepatic inflammation, hepatic and renal damage, and hematologic changes in dogs and rodents. Inhalation by humans has been reported to cause immediate allergic responses of dyspnea and asthma and clinical symptoms of acute liver damage and chronic hepatitis (CIR 1994). CIR (1994) recommends that in products intended for prolonged contact with the skin, the concentration of ethanolamines should not exceed 5%. 2-Amino ethanol should be used only in rinse-off products. Classification 2-Amino ethanol is included in Annex 1 of list of dangerous substances of Council Directive 67/548/EEC and classified as Harmful (Xn) with the risk phrase R20 (Harmful by inhalation) and Irritant (Xi) with the risk phrases R36/37/38 (Irritating to eyes, respiratory system and skin). The Danish occupational exposure limit is 2.5 mg/m3 (Arbejdstilsynet 2000). 11.9 Dipropylene glycolEcotoxicology Dipropylene glycol (CAS No. 25265-71-8) is inherently biodegradable as 100% degradation was observed in a Zahn-Wellens tests (OECD 302B). In a closed bottle test (OECD 301D), only 16% ThOD was attained during 28 days (IUCLID 2000). Dipropylene glycol does not bioconcentrate in aquatic organisms as BCF values in the range 0.3-4.6 were observed in a 42 day bioaccumulation study with carp (Cyprinus carpio) (IUCLID 2000). A low bioconcentration potential is also indicated by the log Kow of -1.49. The toxicity of dipropylene glycol towards fish is very low with EC50 values > 1,000 mg/l (IUCLID 2000). There was no data found on the effects of dipropylene glycol towards algae and crustaceans. Human health Dipropylene glycol is of low acute oral and dermal toxicity in laboratory animals. Oral rat LD50 is 14,850 mg/kg (RTECS 1999). Ingestion of large amounts may give effects on the central nervous system and kidney, liver, lung and spleen damage. Dipropylene glycol is a mild irritant. Repeated applications of dilute solutions have not produced sensitization in volunteers (BIBRA 1991). No developmental toxicity was seen after oral exposure of pregnant rats and rabbits (NTIS 1992a; NTIS 1992b). Classification Dipropylene glycol is not included in Annex 1 of list of dangerous substances of Council Directive 67/548/EEC.
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