Flow-through biomonitoring applied to a power plant effluent, with emphasis on arsenic bioaccumulation [300 fathead minnow, Pimephales promelas, 300 bluegill, Lepomis macrochirus]

Continuous flow-through effluent biomonitoring studies were conducted at a steam electric station (SES) for 128 days with 300 fathead minnow (Pimephales promelas) and 300 bluegill (Lepomis macrochirus). Fishes were exposed in a mobile environmental research lab ("MERLin") to three water types: 1) Control—from the receiving stream; 2) Effluent—undiluted SES wastewater; and 3) Mixed—from the receiving stream below the point of SES discharge. Various physicochemical and biological parameters were measured. During the study, subsamples of fishes were removed at 30-day intervals to assess condition and growth and for whole-body arsenic analysis by neutron activation techniques. At the end of 128 days control mortalities were 13% and 24% for fathead minnow and bluegill, respectively; while Effluent mortalities were 8% and 24%, respectively. Significant increases in growth occurred in both species over the 128 days, and for both Effluent vs. Control waters. Whole-body analysis for arsenic indicated Effluent fishes contained higher levels than did Control fishes and fathead minnow accumulated arsenic to higher levels than did bluegill. Both fish species survived and grew in the undiluted SES effluent and mixed waters, and did not appear adversely affected by effluent water or arsenic bioaccumulation. Higher bluegill mortalities in both Control and Effluent waters appeared to be related to dominance behavior.