Assessing the effects of pulsed waterborne copper toxicity on life-stage tilapia populations.

The impact of environmentally pulsed metal exposure on aquatic organisms is poorly understood experimentally. The purpose of this study was to provide an analysis methodology for assessing the effects of pulsed waterborne copper (Cu) on life-stage tilapia populations. We conducted 10-day exposure experiments to obtain toxicokinetic parameters for larva, juvenile, and adult tilapia exposed to pulsed Cu. We linked threshold damage model and biotic ligand model to assess the survival probability for tilapia populations to pulsed Cu exposure. Here we showed that the change in exposure patterns did change substantially survival rates for each life stage of tilapia. We indicated that an apparent difference in time course of survival probability between pulsed and constant Cu exposures was found in each life stage. We concluded that the life-stage factor needs to be incorporated into studies of species interactions under different disturbance regimes. This study suggested that life-stage-specific toxicokinetic parameters and adequate water chemistry might be important to consider in risk assessment of population survivorship for aquatic species under pulsed exposure scenarios.