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Investigations are available concerning the toxicity of cumene to aquatic organisms from different systematic classes including also non-standard tests: Short-term and/or long-term effects of cumene were investigated in fish, aquatic invertebrates, aquatic algae, aquatic macrophytes and aquatic microorganisms. The effects on fish and invertebrates were tested using freshwater and saltwater species.

 

For assessing short-term effects in fish, reliable 96 h LC50 values are available from 4 tests with several fish species. The 96-hour LC50 values are in the range of 2.7 and 4.8 mg/L. Two flow-through studies were conducted according to EPA OTS 797 with a freshwater and a marine species under GLP conditions and the complete study reports are available. The LC50 values based on mean measured concentrations obtained in the GLP studies were considered most relevant for the aquatic hazard assessment:

96 h LC50 Oncorhynchus mykiss 4.7 mg/L and 96 h LC50 Cyprinodon variegatus 4.8 mg/L. The data indicate that there is a comparable sensitivity of freshwater and marine fish.

Studies on long-term effects on fish are not available. As cumene is considered as a non polar narcotic and the similar range of acute toxicity data is observed for fish, invertebrates and algae, it was previously accepted by the TM that, in order to reduce testing with vertebrates, the chronic toxicity studies should be conducted only with Daphnia and algae, while QSAR calculations should be employed for the estimation of chronic toxicity on fish after checking the validity of this approach. Chronic NOECs for fish and daphnia have been calculated by the rapporteur of the EU RAR (2001) following the QSAR equations for non polar narcosis included in the Technical Guidance Document (Part III, according to Verhaar et al., 1995).

The results are 0.38 mg/L for fish (QSAR for Early Life Stage toxicity, exposure 28 -32 d) and 0.32 mg/L for Daphnia. The comparison of the measured (0.35 mg/L) and calculated (0.32 mg/L) Daphnia NOEC indicate the validity of the approach and the NOEC for fish of 0.38 mg/L will be used in the assessment.

Out of the nine reliable short-term tests with aquatic invertebrates, five studies were performed with freshwater and four studies with marine species. Focusing on studies with measured concentrations and standard exposure times only, three 48 hour EC50 values for D. magna are available (2.14, 4.0 and 10.8 mg/L). For marine invertebrates three EC50 values based on measured concentrations are reported: 96 hour EC50 values for Mysidopsis bahia of 1.2 and 1.3 mg/L and for EC50 values for Artemia salina of 110 mg/L (24 h) and 7.4 mg/L (48 h).

Two GLP studies were conducted according to EPA OTS 797 under flow-through conditions with a freshwater and a marine species and the complete study reports are available. The EC50 values based on mean measured concentrations of these studies were considered most reliable and relevant for the aquatic hazard assessment: The 48 h EC50 for the freshwater species Daphnia magna is 4.0 mg/L and the 96 h EC50 for the marine Mysidopsis bahia is 1.2 mg/L. The most recent study of P&D (2010) was conducted in closed vessels under static conditions. The EC50 value is based on mean measured concentrations. Out of the freshwater studies the lowest EC50 value obtained by P&D is considered most relevant. As for fish, the data indicate that there is a comparable sensitivity of freshwater and marine crustaceans.

Freshwater: 48 h EC50 Daphnia magna 2.14 mg/L

Marine: 96 h EC50 Mysidopsis bahia1.2 mg/L

For the aquatic hazard assessment both, freshwater and marine, the loewest EC50 value of 1.2 mg/L obtained withM. bahiashould be used.

For assessing long-term effects of cumene on Daphnia magna one study is available performed according to OECD 211/Draft, conducted under GLP. The effects on reproduction of D. magna were studied under static renewal conditions in sealed flasks. Mean measured concentrations were used for the evaluation. The 21 day NOEC for effects on reproduction based on mean measured concentrations is 0.35 mg/L. The study is classified as acceptable and valid and satisfies the guideline requirements for a chronic toxicity study with freshwater invertebrates. Measurements of body length of parents, observation of presence of males or ephippia were not conducted as required in the current guideline. However, as the reported NOEC for reproduction could be confirmed by QSAR modelling (EU RAR 2001 using equation of TGD Part III => EC50 0.32 mg/L), it is concluded that the NOEC of 0.35 mg/L can be used for the assessment of long-term risk for aquatic invertebrates.

Three reliable studies on long-term effects of cumene on aquatic green algae are available performed according to OECD 201 and two of the studies were conducted under GLP (P&D 2010, APA/CEFIC 1998). The effects were studied using sealed flasks due to the volatility of cumene. Mean measured concentrations were used for the evaluations. The 72 h EbC50 values based on biomass are 1.29 (P&D 2010), 2.6 (Galassi et al., 1988) and 2.6 mg/L (APA/CEFIC 1998). The ErC50 and ErC10 for growth rate was 2.01 mg/L and 1.35 mg/L, respectively, and the NOEC relevant for the long-term assessment, was 1.49 mg/L in the GLP study of P&D (2010).

Using the data from the GLP study (APA/CEFIC 1998) the ErC50 was calculated to be 4.27 mg/L and the ErC10 was 3.36 mg/L. The NOEC for growth rate was recalculated by the reviewer to be 2.4 mg/L. The results support the findings obtained in the study of P&D (2010). The data of the latter study are used as key values for the chemical safety assessment, since they are the most reliable and the lowest values out of the available studies (ErC50 2.01mg/L and NOEC 1.49 mg/L).

In the respiration test according to OECD 209, cumene exhibited no significant toxic effects towards activated sludge at concentrations up to 2000 mg/L. Therefore, the EC10 is determined to be 2000 mg/L.