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| CATEGORY | QUALITY | THRESHOLD | OCCURENCE | REFERENCE |
|---|---|---|---|---|
| smell | hydrocarbon | water | details | |
| smell | hydrocarbon | 6.856e-2 µmol/L | water | details |
| Toxicity Summary |
|---|
| Link to the Distributed Structure-Searchable Toxicity (DSSTox) Database |
| Human Health. tert-amyl methyl ether (TAME) is absorbed efficiently from the rat intestine. TAME is rapidly absorbed from lungs; the respiration net uptake is 40 %. Studies with tert-methyl butyl ether (MTBE) suggest one third or less of a dermal TAME dose is absorbed. In rats, TAME is distributed evenly in the body. Urine is the main route of elimination. Based on human volunteer studies, the half-lives in blood varied between 1.2 and 6.3 hours. The main urine metabolites are 2-methyl-2,3- butanediol, 2-hydroxy-2-methylbutyric acid and 3-hydroxy-3-methylbutyric acid. Free and conjugated TAA (tert-amyl alcohol) and TAME were only minor metabolites in urine. The acute toxicity of TAME is not high. The LC50 value via inhalation is over 5.3 mg/l. The predicted oral LD50 was for females 1602 mg/kg, males 2417 mg/kg and combined 2152 mg/kg. Although no dermal studies were available, toxicity via skin is not likely to be higher than via oral route. TAME is not irritating to skin or eyes or sensitizing. The toxicity caused by TAME in repeated exposures is not severe. A NOAEC of 250 ppm (1060 mg/cu m) is selected for respiratory exposure based on the organ weight increases of liver, adrenals and kidneys seen in a 90 day study in F-344 rat with both sexes. Via oral route, a LOAEL of 125 mg/kg was established based on the adrenal weight increase in the male rats. TAME did not cause point mutations in bacterial assays or in Chinese hamster ovary cell. In Chinese hamster ovary cells in vitro, TAME caused a clear dose-related increase of chromosome aberrations, which increased when metabolic activation was present. However, a micronucleus study conducted in mice was negative at all sampling times. In the light of present data, TAME cannot be considered mutagenic. No reliable carcinogenicity studies were available In a 2-generation reproductive study, TAME was not toxic to reproduction in rat (NOAEC of 3000 ppm (12720 mg/cu m). In the same study, NOAEC of 250 ppm was found for offspring toxicity and for adult systemic toxicity. In a developmental toxicity study with rats, the only noted effect was foetal weight reduction at 3500 ppm. From a developmental toxicity study with mice, a NOAEC of 250 ppm (1063 mg/cu m) was selected for developmental effects based on malformations (cleft palate) seen at 1500 ppm and 3500 ppm. It is plausible that cleft palates are a secondary effect related to anesthesia and/or maternal stress. Taking into consideration that the cleft palates were seen only at very high TAME concentrations, and because there were no adverse developmental effects seen in rats, the effect noted in mice is not likely to be of consequence to humans. Environment. TAME is a volatile (vp. 90 hPa at 20 o C) liquid which is hydrolytically stable and moderately soluble in water (11 g/L at 20 oC). Static equilibrium partitioning between environmental compartments at 20 oC is as follows: air 95.6, water 4.25, sediment 0.001 and soil 0.038 (EQC ver1.1). TAME is very mobile in soil and may easily leach to groundwater (transported with water). TAME is easily volatilized into the atmosphere from top soil and surface water. Photodegradation in the atmosphere is the primary route of removal in the environment and degradation half-life is ca. 3 to 5 days. Biodegradation in soil, sediment, surface- and groundwater is very slow and TAME may be regarded persistent in these compartments. However, in industrial waste water sewage treatment plants having continuous TAME exposure, adapted microbial population capable of effectively degrading TAME may exist. It is unlikely that TAME would bioconcentrate in high extent or would accumulate in biota for long time periods. The measured log Kow is 1.55 and the calculated BCF in fish is 4. The lowest valid aquatic acute and (one) chronic toxicity test results for fish, daphnids, algae and bacteria are below. Terrestrial toxicity results are not available. (1): Oncorhynchus mykiss: 96 hr-LC50 = 580 mg/L (2): Daphnia magna: 48 hr-EC50 = 100 mg/L and Americamysis bahia: 96 hr-LC50 = 14 mg/L, 28-day NOEC = 3.4 mg/L (3): Pseudokirchneriella subcapitata: 72 hr-EbC50 = 230 mg/L; 72 hr-ErC50 = 780 mg/L; 72 hr-NOEC = 77 mg/L (4): Pseudomonas putida, cell multiplication inhibition test: 16 hr-EC10 = 25 mg/L; 16 hr-EC50 580 mg/L The aquatic PNEC is 0.068 mg/L based on the Americamysis bahia chronic test result (AF=50) and the PNEC for intermittent release is 1.4 mg/L (AF=10). The PNEC for micro-organism is 25 mg/L (AF=1). The terrestrial PNEC is 0.035 mg/kg wwt calculated from the aquatic PNEC using the equilibrium partitioning method. |
| Source: DrugBank or Hazardous Substances Data Bank (HSDB) |