Reaction mass of divinylbenzene and ethylstyrene

Endpoint summary

Additional information

A total of six acute toxicity studies with freshwater fish, four acute toxicity tests and one chronic toxicity test with the freshwater invertebrate, Daphnia magna, and one toxicity test with a freshwater algae were performed using different grades of the reaction mass of divinylbenzene and ethylstyrene. Based on a review of the ecotoxicity values from the acute studies, the DVB-HP grade (approximately 80% divinylbenzene/20% ethystyrene) exhibited greater toxicity as compared to the other grades of divinylbenzene and ethylstyrene (DVB-55: approximately 55% divinylbenzene/ 45% ethylstyrene) and DVB-63: approximately 63% divinylbenzene and 37% ethystyrene). Thus, toxicity data for DVB-HP was used as a worst case approximation of toxicity for all other existing grades of the reaction mass. A 14 -day LC50 of 1.78 mg/L DVB-HP in medaka was the lowest acute endpoint for fish. For aquatic invertebrates, the lowest acute toxicity value of 1.14 mg/L DVB-HP was calculated as a geometric mean from two high quality studies with Daphnia magna. One high quality toxicity study with Selenastrum capricornutum was performed with DVB-HP. The 72-hour NOEC (based on biomass) was 0.81 mg/L DVB-HP, and the 72-hour EC50 (based on biomass) was 1.73 mg/L DVB-HP. Based on all the aquatic toxicity data for DVB-HP, the lowest acute toxicity value was 1.14 mg/L, which was based on two acute studies with Daphnia magna. The chronic toxicity values of 0.353 and 0.81 mg/L for DVB-HP were based on a 21-day NOEC(reproduction) in Daphnia magna and a 72 -hour NOEC(biomass) in Selentastrum capricornutum, respectively. The NOEC(reproduction) for Daphnia magna was the lowest toxicity value for DVB-HP and therefore, this value was used to derive predicted no effect concentrations in freshwater.