4,4'-isopropylidenedi-2,6-xylol

Short-term toxicity to aquatic invertebrates

Description of key information

The 48-h EC50 is 3.1 mg/L in aquatic invertebrates (D. magna).

Additional information

A GLP compliant study was performed, according to OECD guideline 202, to estimate the acute toxicity (EC50) of tetramethyl bisphenol A to Water Fleas (Daphnia magna) under static test conditions. Based on a preliminary test and consultation with the study sponsor, nominal concentrations of 0.31, 0.63, 1.3, 2.5, 5.0 and 10 mg/L were selected for the definitive exposure. Daphnids, less than 24 hours old, were impartially selected and distributed to intermediate vessels. Each test concentration contained 4 replicate test vessels with 5 daphnids per vessel for a total of 20 daphnids per exposure concentration.The test was initiated when the daphnids from each intermediate vessel were added to each exposure vessel.The number of immobilized daphnids in each replicate test vessel was recorded at 0, 24 and 48 hours of exposure. Biological observations and observations of the physical characteristics of each replicate test solution were also made and recorded at 0, 24 and 48 hours. The pH, dissolved oxygen concentration and temperature were measured at 0 and 48 hours. Following 24 hours of exposure, immobilization of 5, 0, 0, 0, 25, and 80% was observed among daphnids exposed to the 0.32, 0.48, 1.2, 2.3, 4.9, and 9.2 mg/L treatment levels, respectively. Three daphnids exposed to the 2.3 mg/L treatment level were observed to be lethargic. Several daphnids exposed to the 4.9 mg/L treatment level were observed to be lethargic. Several daphnids exposed to the 4.9 and 9.2 mg/L treatment level were observed to be on the bottom of the test vessel. Following 48 hours of exposure 5, 0, 5, 10, 100 and 100% immobilization was observed among daphnids exposed to the 0.32, 0.48, 1.2, 2.3, 4.9 and 9.2 mg/L treatment levels, respectively. The immobilization (5%) observed in the 0.32 mg/L treatment level, is not considered an adverse response from exposure to the test substance as the next higher concentration (i.e. 0.48 mg/L) was observed to have no effect. No immobilization or adverse effects were observed among daphnids exposed to the 0.48 mg/L treatment level, control or the solvent control. Several daphnids exposed to the 2.3 mg/L treatment level were observed to be lethargic. The calculated 24 and 48 hour EC50 (95% confidence intervals) values were 6.5 mg/mL (4.7-8.9 mg/L) and 3.1 mg/L (2.7 – 3.5 mg/L), respectively. The No-observed-effect concentration (NOEC) was determined to be 0.48 mg/L. The highest concentration producing 0% toxicant related immobilization was 0.48 mg/L and the lowest concentration producing 100% immobilization was 4.9 mg/L.