Which method describes bioassay used in water quality testing?

The bioassay method involves using living organisms to evaluate the toxicity of water samples. This approach assesses how different organisms respond to the chemical and biological characteristics of the water, providing insight into its overall quality and potential hazards. By observing the effects on these indicator organisms, researchers can gauge the levels of pollutants or toxic substances present in the water. This method is especially valuable because it integrates the biological impact of contaminants, rather than just measuring chemical concentrations.

Using indicator organisms highlights the bioavailability of harmful substances and their effects on ecosystems, making this method particularly relevant in environmental monitoring. Other approaches, such as random sampling, measuring physical properties, and analyzing dissolved oxygen levels, may provide useful data but do not specifically address the biological impact of toxic substances in a direct way like bioassays do.