A soil and water interface study evaluating toxicity of different hazardous chemicals using vibrio harveyi in an aquatic toxicity test

Abstract

Toxicity of thirty one different chemicals was evaluated in a soil and water interface environment using the bioluminescent marine bacterium Vibrio harveyi as the test organism. Toxicity was reported by the chemicals ability to reduce bioluminescence of the test organism by 50%, which is represented as an estimated median effective concentration (EC₅₀). Interaction of the chemical and sediment, soil, was performed for 24 hours, afterwards the test organism was added and allowed to interact with this interface mixture for 50 minutes. Toxicity was then evaluated by the amount of bioluminescence reduced by the interface mixture as compared to a control. Chemicals tested included representative metals, oxidizers/electron transport inhibitors and organics. Toxicity was reduced in this soil interface compared to other studies that used this procedure and test organism for soil and sand extractions with and without an acid wash, and water (buffer) alone. Overall, toxicity of these metals appears to be more effectively reduced than that of the oxidizers/electron transport inhibitors or organics. These data suggest that soil is binding the chemicals, thus reducing their availability to exhibit toxic effects on the test organism. Two statistical procedures, a confidence interval and a two‐fold difference, were used to evaluate effective concentration data from this study and other studies. Data from this study suggest that sediment can effectively reduce the toxicity to organisms and may act as a sink for these chemicals. The ability of sediment to influence the toxicity of chemicals is highly variable and each chemical appears to have its own toxicity characteristic to the test organism. Variability of toxicity is also dependent on the type of sediment and physical factors that are applied based on data in this investigation and similar studies. The importance of sediment as related to environmental toxicity in various ecosystems is discussed.

Keywords:

• Bioluminescence
• bioassay
• pollution
• toxicity testing
• sediment
• environmental toxicity