Reaction mass of 2,6-bis(1-phenylethyl)phenol and 2,4,6-tris(1-phenylethyl)phenol

Endpoint summary

Additional information

Due to the differences in the physicochemical characteristics of the components of the reaction mass of 2,4,6 -tris(1 -phenylethyl)phenol and Bis(1 -phenylethyl)phenol, any distyrenated phenol and tristyrenated phenol released to the environment will not behave as a single compound. Significant variation is expected in the toxicity of this compounds. As a consequence, it was considered more appropriate to conduct the aquatic toxicity assessment for each component, that is to say for Tristyrenated phenol (TSP) and Distyrenated phenol (DSP).

For freshwater fish, only one acute toxicity test is available (BAZZON, 1997), performed on a mixture of DSP and DSP (80% and 20% respectively). The results showed no mortality at the saturated concentration. Even if this study has been conducted according to the OECD guideline and the GLP, it is considered as reliable with restriction because no analytical monitoring has been performed. No long term toxicity data are available.

A fish sexual development test (FSDT) was performed with zebrafish (Danio rerio). The objective of this study was the assessment of effects of continuous exposure to 4-(1-phenylethyl)-phenol (4-MSP) on the early life stages and sexual differentiation of zebrafish (Danio rerio), following the OECD test guideline 234.

No significant effect was found at all tested concentrations for non-endocrine apical endpoints.

Based on the endocrine-related endpoints, a NOEC of 61.8 µg/L 4 -MSP (mean measured concentrations) was determined based on the decrease of the number of males in the highest test concentration. Furthermore, the mean values for the biomarker VTG indicated a statistically significant increase of the VTG concentration in the blood plasma of females and undifferentiated fish. These results suggests a strong estrogenic mode of action for the test substance.

For freshwater invertebrates, one acute toxicity test is available to Daphnia magna (LAMY, 1997), performed on a mixture of DSP and DSP (80% and 20% respectively). The results showed that the 48h EC50 value is higher than the saturated concentration. Even if this study has been conducted according to the OECD guideline and the GLP, it is considered as reliable with restriction because no analytical monitoring has been performed. Two long term toxicity studies to Daphnia magna are available. The first one (NOACK, 2008) has been performed on TSP and showed no statistically significant effects on reproduction, adult mortality and growth at saturated solution of 35 µg/L (arithmetic mean of the measured concentrations). The second study (NOACK, 2006) has been performed on DSP and showed a 21d NOEC of 115 µg/L for both reproduction and parental immobilisation. As both studies were performed according to the OECD guideline and GLP, they are considered as reliable without restriction and they are used for the hazard assessment of the substance.

For algae, two toxicity studies to Desmodesmus subspicatus are available. The first one (NOACK, 2010) has been performed on TSP and showed no statistically biologically significant effects on growth rate of the algae at saturated solution of 5.15 µg/L (geometric mean of the measured concentrations). The second study (NOACK, 2010) has been performed on DSP and showed a 72h NOEC of 140 µg/L and a 72h EC50 of 326 µg/L for growth rate. As both studies were performed according to the OECD guideline and GLP, they are considered as reliable without restriction and they are used for the hazard assessment of the substance.