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OECD 203: Fish, Acute Toxicity Test

OECD 203 is an acute toxicity test that evaluates the toxicity of a test substance to different fish species.

Standard testing for OECD 203 exposes fish to a test substance for a period of 96 hours.
Mortalities are recorded at 24, 48, 72, and 96 hours, and the concentrations OECD 203 determine the toxicity of a test substance to freshwater fish; most commonly zebrafish and fathead minnowsthat kill 50% of the fish are determined when possible.

At least five test concentrations are analyzed during testing. A range finding test is conducted to help determine the appropriate test concentrations.

The most commonly requested test organism for OECD 203 is Zebra-fish, however, testing can be performed against a variety of method approved fish species. Please inquire with the lab regarding additional options*.

OECD 203 is recommended as a preliminary analysis for toxicology studies. Once the acute test has been conducted, many customers will proceed with Chronic Toxicity testing and Bioaccumulation studies.

For a full Ecological Effects and Environmental Fate analysis, customers will request Biodegradability determination, Acute and Chronic Toxicology testing, and Bioaccumulation Analysis.  These three categories together provide a comprehensive picture of how a test sample or product may affect and persist in the environment during use and after disposal.

Additional Testing Options

For a Chronic toxicity analysis, customers commonly request OECD 215; Fish, Juvenile Growth Test.

Additionally, OPPTS 850.1075; Fish Acute Toxicity Test, Freshwater and Marine is a requested acute fish toxicity test that can evaluate freshwater or marine fish toxicity.  The most common marine fish species for laboratory testing is the Sheepshead minnow.

For any toxicology testing, it is beneficial to have data on different properties of the material, including structural formula, water solubility*, purity of the substance, stability in water and light, Partition Coefficient*, and ready biodegradability.

Regulatory and Branding Information

For EPA Pesticide Registration, as part of Series 850: Ecological Effects, Technical Grade Active Ingredients (TGAI) and Typical End-Use Products (TEP) are required to submit toxicity data on one cold water and one freshwater fish species if the application is intended for aquatic, forestry, and/or residential outdoor uses. For indoor and greenhouse uses, testing is only required for one of either fish species.

Toxicology testing is commonly required for environmentally acceptable product label claims. For example, Lubricants trying to achieve the EU Ecolabel are required to undergo a variety of tests.  For the Toxicity component, OECD 203 is one of the recommended methods for the required data on a lubricant’s toxicity to fish.

Fish, aquatic plants, and aqueous invertebrate organisms are constantly at risk for exposure to lubricants through accidental spill, stern tube leakage, and discharge.  Lubricants that claim to be environmentally acceptable with the EU Ecolabel for Lubricants are highly accepted and gain a competitive edge in the market.

For any testing performed to meet regulatory or third party branding requirements, it is strongly recommended to review requirements prior to testing with the appropriate agency to determine which tests should be performed for label claims or regulatory acceptance.  

Situ Biosciences LLC offers consulting services for the determination, confirmation and testing to meet regulatory and third party branding requirements. 

* Please inquire with the lab to set up a GLP Toxicology Study.

* Some fish species require additional lead time prior to testing; please inquire with the lab prior to testing for specific fish species requirements.

* OECD 105: Water Solubility

*OECD 117: Partition Coefficient (n-octanol/water), HPLC Method

For more information on Toxicology testing, contact our Environmental test laboratory at 847-483-9950 or info@situtest.com.