OECD 202 Daphnia Acute Immobilisation Hazardous Waste Toxicity Test
The OECD 202 Daphnia Acute Immobilisation Test (AIT) is a standardized method used to assess the acute toxicity of chemical substances or mixtures in water, particularly relevant for hazardous waste and industrial effluents. This test is a critical component in environmental compliance evaluations and supports regulatory decision-making processes.
The OECD 202 AIT uses Daphnia magna, commonly known as water fleas, which are small crustaceans that inhabit freshwater ecosystems. These organisms serve as sentinel species due to their rapid response to toxicants and their sensitivity to environmental changes. The test provides a quick indication of the toxicity of a substance by measuring the mortality or immobilization rates of Daphnia in contact with the test solution.
The OECD 202 AIT is governed by ISO standard 11348-5:2009, which specifies procedures for testing the acute toxicity using the Daphnia AIT. This method is widely recognized and accepted globally due to its robustness and reliability in predicting adverse effects on aquatic organisms.
The test setup involves exposing Daphnia magna to a dilution series of the test substance, typically ranging from 100% (highest concentration) down to 0.5% (lowest concentration). The endpoints measured are the percentage of immobilized individuals and mortality rates over a 48-hour exposure period.
The OECD 202 AIT is particularly useful for hazardous waste disposal as it provides an early warning system for potential environmental impacts. It helps in assessing the risks associated with industrial effluents, sewage treatment plant discharges, and other sources of water contamination. By identifying toxic substances at an early stage, this test aids in implementing corrective measures to prevent broader ecological harm.
The Daphnia AIT is one of several OECD methods for evaluating chemical toxicity, complementing tests like the OECD 203 Fish Early-Life Stage Test or the OECD 414 Luminescent Lysate Assay. Together, these tests offer a comprehensive approach to understanding and managing environmental risks.
The test results are reported as EC50 (effective concentration for 50% immobilization) values, which indicate the toxicity of the chemical substance under test conditions. These values help regulatory bodies in setting appropriate discharge limits and in formulating risk management strategies.
Scope and Methodology
| Test Parameter | Description |
|---|---|
| Daphnia Magna Population | 24 individual Daphnia magna are used in the test. |
| Test Substance Concentration Series | The test substance is prepared in a series of dilutions ranging from 100% to 0.5%. |
| Exposure Time | The Daphnia magna are exposed to the test solution for 48 hours. |
| Endpoint Measurement | The percentage of immobilized individuals and mortality rates are recorded. |
The OECD 202 AIT is conducted in a controlled laboratory environment, ensuring the integrity and reliability of test results. The protocol strictly adheres to ISO standard 11348-5:2009, which specifies the conditions for conducting the test, including temperature control (20°C ± 1°C) and pH adjustment to neutral.
The test substance is typically prepared using high-quality reagents that meet international standards. The dilution series ensures a comprehensive evaluation of the substance’s toxicity across various concentrations. The Daphnia magna are acclimated for at least 24 hours before testing, ensuring they are in optimal health and capable of providing accurate results.
The test is conducted in triplicate to ensure reproducibility and reliability. This approach helps minimize variability in the results due to experimental errors or environmental factors. The use of Daphnia magna as the test organism ensures that the results are indicative of potential impacts on aquatic ecosystems, providing valuable insights for environmental risk assessments.
Benefits
The OECD 202 Daphnia Acute Immobilisation Test offers numerous benefits in the field of hazardous waste and chemical disposal testing. These include:
- Rapid Toxicity Assessment: The test provides a quick evaluation of the acute toxicity of chemicals, enabling timely interventions.
- Regulatory Compliance: By adhering to ISO standards, this method ensures that testing aligns with international regulatory requirements.
- Risk Management: It helps in identifying hazardous substances early, allowing for the implementation of preventive measures.
- Eco-friendly: The test aids in minimizing environmental risks by providing data on potential toxic effects on aquatic ecosystems.
- Data Integrity: Reproducible results ensure consistent and reliable data across different laboratories.
The OECD 202 AIT is a cornerstone of environmental testing, particularly for industries dealing with hazardous waste. It supports decision-making processes by providing actionable insights into the potential impacts of chemical substances on aquatic environments.
Use Cases and Application Examples
| Application Case | Description |
|---|---|
| Industrial Effluents: | Evaluating the toxicity of industrial wastewater discharged into freshwater bodies. |
| Sewage Treatment Plant Discharges: | Assessing the impact of treated sewage on aquatic ecosystems before release. |
| Hazardous Waste Management: | Determining the toxicity of hazardous waste during disposal or recycling processes. |
| New Chemical Substances: | Evaluating the toxicity of newly developed chemical substances before market release. |
The OECD 202 AIT is widely used in various industries, including manufacturing, pharmaceuticals, and environmental management. Its application spans from regulatory compliance to research and development (R&D) initiatives aimed at minimizing environmental impacts.
For instance, a chemical manufacturer may use the Daphnia AIT to assess the toxicity of a newly synthesized compound before it is introduced into the market or discharged into water bodies. Similarly, an industrial plant could employ this test to evaluate the effectiveness of its wastewater treatment processes and ensure compliance with environmental regulations.
The results of these tests are often integrated into broader risk assessment frameworks, providing stakeholders with a comprehensive understanding of potential risks and enabling informed decision-making.
