Investigating Gasoline Contamination Effects on Daphnia’s Heartbeat in a Simulated Lake

Gasoline evaporates quickly on the water's surface compared to other liquid agents. Gasoline, even in trivial amounts, can adversely affect fish and plants that live there. Its vapors may be toxic to birds and mammals at high concentrations. On land, spilled gasoline can rapidly diffuse into the soil, potentially causing groundwater or surface water contamination. And, the gasoline swept with water should be collected into the much larger water body such as lakes and rivers, in which Daphnia thrives while assisting the healthy ecology of so many other aquatic organisms.

This study used groups of beakers filled with gasoline-contaminated water, vegetable-ground organic materials, and a magnetic stirrer, simulating water currents and organic components in freshwater reservoirs. The effects of gasoline concentrations, organic matter existence, and temperature were investigated. The results showed that the gasoline was highly toxic for the survival of Daphnia, considering their death at a relative concentration of less than 0.1mL of 0.01 ml gasoline/water solution. The heartbeat change% and survival% in 1.0-hour incubation were mathematically proportional to the variables of gasoline concentration, temperature and organic matter amounts, and stirring forces in the gasoline-contaminated water. The dependency of each variable was quantitatively identified. Further study might be needed to understand deeper for mutual relationships of the variables.