reaction mass of isomers of: C7-9-alkyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

Bioaccumulation: aquatic / sediment

Description of key information

Slight bioaccumulation potential of Butyl 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoate (CAS 52449-44-2): BCF = 49, Mino, 2002). 

Key value for chemical safety assessment

BCF (aquatic species):

49 L/kg ww

Additional information

An experimental result is available for Butyl 3,5 -bis(1,1 -dimethylethyl)-4 -hydroxybenzenepropanoate (CAS 52449 -44 -2), which is used as a read-across possibility (Mino, 2002). The test was conducted according to the test method relating to New Chemical Substances (1974, amended 1998), which prescribes the procedure for testing new chemical substances as required by the Chemical Substances Control Law of Japan. Before starting the bioconcentration test , an acute toxicity test with Medaka (Oryzias latipes) was conducted for 96 hours and the 50 % lethal concentration (LC50) was determined. Afterwards, the bioconcentration study was carried out at two concentration levels not exceeding a hundredth and a thousandth of the LC(96h)-value.Cyprinus carpio(carp) was selected as test organisms with a total length of 8 +/- 4 cm and about 5 g body weight. As receiving the animals, visual observation was done and healthy fish were reared in an aquarium with water flowing through. The acclimatisation period was about 2 weeks, whereby the fish were kept without receiving medicine in the aquarium. The mortality during the last week before testing was less than 5 %. The bioconcentration test system was set up in triplicate. During the exposure period of 35 days, the concentrations of the test substance in water and fish were measured periodically. The bioconcentration factors (BCF) calculated from the results were used to evaluate the potential for the test substance to accumulate in the tissues of carp. The pH value was within the range 6.0 to 8.5. No abnormality in bodyshape or in swimming and feeding behaviour during the period of the test were recorded. The fat content was measured as 6.6 % (n= 3, 5.9 - 7.3 %) at the beginning and 5.6 % (n=3, 4.9 - 6.8 %) at the end (within +/- 25 % range of the average at the beginning of the exposure period). The concentration levels over the exposure period averaged 0.0483 mg/L at high concentration level and 0.00475 mg/L at low concentration level, satisfactorily close to the nominal values. The coefficients of variation were 4.2 % and 8.8 %, respectively. These concentrations of the test substance in the chamber were maintained within +/- 20 % of the mean of the measured values. The concentrations of the test substance in fish were 1.58-3.60 µg/g at high concentration level and 0.147-0.248 µg/g at low concentration level, and the bioconcentration factors (BCF) were 33-75 and 30-52 at steady state, respectively. On the basis of the BCF obtained, it can be concluded that the possibility for fishes to bioaccumulate the test substance is slight under the prescribed test conditions.

No experimental results are available for Benzenepropanoic acid, 3,5 -bis(1,1 -dimethylethyl)-4 -hydroxy-,C7 -9 branched alkyl esters (CAS 125643 -61 -0). However, the computer program Toxmatch (v1.07) was used to predict the bioconcentration factor of the substance (Chemservice S.A., 2011). The predefined set of 610 chemicals with known BCF was used to estimate a range of BCF for reaction mass of isomers of: C7-9-alkyl 3-(3,5-di-trans-butyl-4-hydroxyphenyl)propionate. The target test chemical was nonyl 3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate, C9 representative of isomeric mixture. The logBCF was predicted using descriptor based Euclidean distance method and two structural similarity methods (Hellinger distance and Tanimoto distance). The predicted logBCF based on Euclidean distance was predicted 1.90, based on Hellinger distance (atom environments) 1.63 and based on Tanimoto distance (fingerprints) 2.66.