Reaction mass of 2,2'-[methylenebis(2,1-phenyleneoxymethylene)]bis(oxirane) and 2,2'-[methylenebis(4,1-phenyleneoxymethylene)]bis(oxirane) and 2-({2-[4-(oxiran-2-ylmethoxy)benzyl]phenoxy}methyl)oxirane

Short-term toxicity to fish

Description of key information

The 96-hour median lethal concentration (LC50) to golden orfe (Leuciscus idus) was calculated to be 5.7 mg/l with 95% confidence limits o f 4.7 - 6.8 mg/l. The no-observed-effect concentration (NOEC) was 3.2 mg/l.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

2.54 mg/L

Additional information

There are five studies for acute fish toxicity that have been performed with the substance described as “formaldehyde, oligomeric reaction products with 1-chloro-2,3-epoxypropane and phenol (CAS# 9003-36-5), Depending of the conditions of the reaction, the formation products can results oligomers up to the polymer molecular weight range and structure. 

 

The products tested for acute daphnia toxicity are a range of these oligomers, EPIKOTE 862 on the low molecular weight end and the TK 12225/D (two studies), DEN 438 and EPIKOTE 155 on the higher end of molecular weights. GPC of these substances are virtually identical with only slight indications to molecular weight range. The EPIKOTE 862 study had a high loading rate and a long mixing time, which had the potential to selectively extract more soluble impurities that could be more toxic. The 96 hour LC₅₀for rainbow trout was 0.55 mg/L. The study with DEN 438 and the two with TK 12225/D both used a solvent to create the test solutions, which created a cloudy suspension not necessarily representative of the toxic action of the substance. Some of the suspension at higher loading rate was observed to precipitate out. The DEN 438 and one of the TK 12225/D studies were performed in non standard species, golden orfe and zebra fish respectively. The 96 hour LC₅₀for DEN 438 using Tween 80-acetone was 5.7 mg/L for golden orfe and the 96 hour LC₅₀for TK 12225/D using DMF in rainbow trout was 2.0 mg/L and 1.9 mg/L in zebra fish. The EPIKOTE 155 study used a high loading rate (1000 mg/L) generate test solutions. The actual concentrations were not measured as the amount soluble in water would be below the level of detection. Even at this high loading rate there was insufficient test material solved in the test solution to exhibit any toxicity. This study reports a 96 hour LC₅₀of >1000 mg/L.

 

To reconcile these studies and develop a dose descriptor for this endpoint, the four studies with the products EPIKOTE 862, DEN 438 and TK 12225/D have been averaged in a weight of evidence approach to obtain the 96 hour LC₅₀and the EPIKOTE 155 study is used as a supporting study. An LC₅₀of 2.54 mg/L is used for this endpoint.