Dimethyl terephthalate

Endpoint summary

Additional information

Dimethyl terephthalate is only slightly soluble in water (ca. 31 mg/L at 20 degrees C) and this property limits the exposure conentrations that are achievable under the conditions of aquatic toxicity tests.

Acute toxicity

Seven guideline-compliant acute toxicity studies (Klimisch 1 or 2) are available for dimethyl terephthalate, which provide endpoints for three key trophic levels (fish, invertebrates and algae). Fish are most acutely sensitive to DMT. The findings of the acute aquatic toxicity studies are outlined below:

Fish

Zebra fish (D. rerio) 96 -h LC50 (semi-static): 13 mg DMT/L, 96 -h NOEC: 9.6 mg DMT/L.

In this study (Anonymous, 1994), the fish were exposed to DMT dosed from a saturated, filtered aqueous stock solution. The endpoints (mean measured) are based on non-specific analysis of dissolved organic carbon (DOC), converted to DMT-equivalents. Since the media were renewed with fresh solutions at 24 -h intervals and since other data are available to demonstrate that DMT would not have undergone abiotic transformation in this timeframe (stability confirmed in aqueous solution and under bright illumination for at least 72 h), the DOC measurements are considered adequate surrogates for the confirmation of DMT exposure.

Himedaka (O. latipes) 96 -h LC50 (semi-static): >5.37 mg DMT/L, 96 -h NOEC: 5.37 mg DMT/L.

In this study (Government of Japan, Ministry of the Environment, 2002a), the fish were exposed to DMT dosed from a stock solution prepared with terahydrofuran. The limit concentration (mean measured) represents the highest achievable dissolved DMT concentration under the conditions of the test.

Invertebrates

D. magna 48 -h EC50 (static): >23.5 mg DMT/L, 48 -h NOEC: 10.8 mg DMT/L.

In this study (Salinas, 2010a), daphnia were exposed to DMT dosed from a saturated, filtered aqueous stock solution. The endpoint (initial, measured) represents the highest achievable dissolved DMT concentration under the conditions of the test.

D. magna 48 -h EC50 (semi-static): >6.50 mg DMT/L, 96 -h NOEC: 6.50 mg DMT/L.

In this study (Government of Japan, Ministry of the Environment, 2002b), daphnia were exposed to DMT dosed from a stock solution prepared with terahydrofuran. The limit concentration (nominal, analytically verified) represents the highest achievable dissolved DMT concentration under the conditions of the test.

Algae

Desmodesmus subspicatus 72 -h ErC50 (static): >29 mg DMT/L, 72 -h NOErC: 29 mg DMT/L

In this study (Salinas, 2010b), algae were exposed to DMT dosed from a saturated, filtered aqueous stock solution. The limit endpoint concentration (initial, measured) represents the maximum achievable DMT concentration under the conditions of the test.

Desmodesmus subspicatus 72 -h ErC50 (static): >32.3 mg DMT/L, 72 -h ErC10: 20.1 mg DMT/L.

In this study (Anonymous, 1993b) D. subspicatus (formerly known as Scenedesmus subspicatus) was exposed to DMT dosed from a saturated aquatic stock solution. The endpoints are mean measured values, based on non-specific organic carbon analysis. The endpoint of 32.3 mg/L represents the maximum DMT concentration achieved under the test conditions.

Pseudokirchneriella subcapitata72 -h ErC50 (static): >6.50 mg DMT/L, 72 -h NOErC: 6.50 mg DMT/L.

In this study (Government of Japan, Ministry of the Environment, 2002d), algae were exposed to DMT dosed from a stock solution prepared with tetrahydrofuran. The endpoint (nominal initial, analytically confirmed) represents the highest achievable dissolved DMT concentration under the conditions of the test.

Long-term toxicity

A Klimish 1 study is available on the long-term toxicity of dimethyl terephthalate to aquatic invertebrates.

D. magna 21 -d NOECrepro (semi-static): 1.72 mg DMT/L, 21 -d EC50 repro: 3.67 mg DMT/L.

In this study (Government of Japan, Ministry of the Environment, 2002c), daphnia were exposed to DMT dosed from a stock solution prepared with terahydrofuran. The adult mortality LC50 was >6.01 mg DMT/L (measured, TWA), which represents the highest achievable DMT concentration under the conditions of the test.

Toxicity to microorganisms

Activated sludge 3 -h EC50 respiration: >1000 mg/L.

In this study (Voelskow, 1989), activated sludge from a predominantly domestic STP was exposed to nominal concentrations of 500 and 1000 mg/L, which both exceeded the solubility limit of the test substance. Slight (10%) inhibition of respiration was observed at 1000 mg/L. The inhibition of respiration remained at 0 % at 500 mg/L. Therefore, the NOEC is deemed to be 500 mg/L.

Pseudomonas putida, 4.5 -h EC50respiration: >2000 mg/L.

In this study (Anonymous, 1993c), performed according to an in-house Huels AG test procedure, the ubiquitous aerobic soil/water bacterium P. putida was exposed to nominal concentratiions ranging from 100 to 2000 mg DMT/L (all exceeding the solubility limit of the test substance).