Oxygen Flux as an Indicator of Physiological Stress in AquaticOrganisms: A Real-Time Biomonitoring System of Water Quality

摘要

The detection of harmful chemicals and biological agents in real time is a critical need for protecting water quality. We studied t he real -time eff ects of fly e env ironmental c ontaminants with di ffering modes o f act ion (atrazi ne, pentachlorophenol, cadmium chloride, malathion, and potassium cyanide) on respiratory oxygen consumption in 2-day post-fertilization fathead minnow (Pimephales promelas) eggs. Our objective was to assess the sensitivity o f fathead minnow eggs using the self-referencing micro-optrode technique to detect instantaneous changes in oxygen consumption after brief exposures to low concentrations of contaminants. Oxy gen consumption data indicated that the technique is indeed sensitive enough to reliably detect physiological alterations induced by all contaminants. After 2 h of exposure, we identified significant increases in oxygen consumption upon exposure to pentachlorophenol (100 an d 1000 μg/L), cadmium chloride (0.0002 and 0.002 μg/L), and atrazine (150 μg g/L). In contrast, we observed a significant decrease in oxygen flux after exposures to potassium cyanide (5.2, 22, and 44 μg/L) and at razine ( 1500 μg/L). N o effects were detected after exposures t o malathion (200 an d 340 μg/L). We have al so tested the s ensitivity o f Daphnia magna embryos as another animal model for real-time environmental bio monitoring. Our results are s o far encouraging and support further dev elopment of this technology as a p hysiologically co upled bi omonitoring tool for t he detection o f environmental toxicants.