Fish Bioassay: Contribution to Water Quality Monitoring and Ecosystem Health

What are the Purpose and Conditions of Fish Biomonitoring (ZSF)?

What is a Fish Bioassay (ZSF)?

A fish bioassay is an ecotoxicology test that examines the effects of contaminants in the aquatic environment on fish. This test includes various toxicity tests applied to fish to determine the effects of water on biological components. In the assessment of water quality, biological tests are used in combination with chemical tests to obtain more holistic and accurate results. Fish bioassay analyzes ecosystem health, especially by examining the effects of pollutants on organisms in aquatic ecosystems at the genetic, morphological and physiological level.

Various biological monitoring methods are used to understand the healthy functioning of aquatic ecosystems and to evaluate the effects of pollutants on water. Fish bioassay (ZSF - Zootoxicological Test) is one of these methods. Fish bioassay is a biological test widely used to monitor water quality and assess ecosystem health.

The fish bioassay is based on the principle of determining whether the fish will remain alive within 48 hours when the effluent is diluted with dilution water in certain proportions. The harmful substances contained in the wastewater adhere to the fins of the fish and pass into the respiratory epithelium and skin or digestive systems, causing poisoning.

The toxic effects of wastewater can be expressed based on the “Toxicity Dilution Factor (ZSF)”, which is expressed as the sum of the relative dilution water volumes per unit volume of wastewater, and the smallest dilution value at which fish can survive.

What are the Prerequisites for Fish Biomonitoring?

• Test fish should be kept in aerated aquariums with chlorine-free drinking water.
• Water circulation should be ensured.
• There should be maximum 5 fish in 1 liter of water.
• Lebistes Reticulatus, Lepomis Macrochirus, Oryzias Latipes, Pimephales Promelas and Poecilia Reticulata are used as test fish.
• Test fish should be 30 mm in length and weigh 0.3 g.
• Test fish should be adapted to 20 ^oC temperature for 48 hours.

How is Fish Bioassay (ZSF) Performed?

Fish bioassay testing is usually carried out by observing fish over a period of time in natural or contaminated water sources from which water samples are taken. The fish species used in the test are selected from species that are sensitive to water conditions and susceptible to toxins. The parameters monitored in the ZSF test are:

• Salinity, pH and temperature: These factors determine the overall quality of the water and show the effects on the health of the fish.
• Fish mortality: This tests whether contaminants in the water environment have a lethal effect on the fish.
• Behavior changes: Contaminants can change the behavior of fish. In this test, the normal mobility, feeding habits and social interactions of fish are examined.
• Physiological disorders: Pollutants can cause damage to fish organs. This is another important parameter observed during the test.

Nanolab Laboratories Group continues to provide services within the scope of Fish Bioassay. We also provide services in Chemical Analysis in Water.

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