The response of the three brood Ceriodaphnia test to fifteen formulations and pure compounds in common use.

The three brood Ceriodaphnia dubia test was carried out on fifteen formulations and pure compounds presently in general use in a variety of treatment processes or as reference toxicants. The most toxic substances (LC50 (based on survival/EC50 (based on total progeny) less than 10 mg/L) were metallic Cu, tertiary dodecyl mercaptan, an antioxidant TIA-RCO T-424, Cu(NO3)2.3H2O, K2Cr2O7, NALCO 7139--a flocculent, DOWFAX 2EP--a surfactant, TB-66--an algicide and ammonia. Exposure to these compounds elicited the same response from C. dubia for the two endpoints examined--survival and reproductive success. Two antimicrobials, PROXEL GXL and DOWICIL 75, and the surfactant sodium lauryl sulfate, were slightly toxic (LC50/EC50 less than 100 mg/L) for both endpoints studied. Two coagulants, NALCO 7109 and NALCO 8120 and a flocculent PERCOL 757 were practically nontoxic (LC50 greater than 100 mg/L) to slightly toxic (LC50 less than 100 mg/L) when the survival endpoint was examined, but were moderately toxic (EC50 less than 10 mg/L) to slightly toxic (EC50 less than 100 mg/L) when the endpoint of reproductive success was examined. These formulations and pure compounds had generally a declining effect on mean brood size, though there were exceptions to this observation as the broods progressed in number.