All study systems caused significant D. magna mortality in undiluted whole effluent samples (100% treatment level; Fig. 3). Though D. magna survival and sublethal responses (growth, reproduction) were examined for each effluent discharge, the sublethal reproduction endpoint is almost always more sensitive to environmental contaminants and effluents than survival and somatic growth. Whereas D. magna mortality and growth endpoints exhibited identical NOECs (50% effluent) for MTP and ATS discharges, chronic toxicity was slightly greater in the ATS system: reproduction NOEC values were 50% effluent for the MTP and 25% effluent for the ATS systems, respectively (Fig. 3)