Lecture toxicity testing
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This document discusses toxicity testing of chemicals in marine environments. It defines aquatic toxicity, degradability, and bioaccumulation as key properties to assess the potential hazards of chemicals. The goal of toxicity tests is to determine the concentration of a chemical that causes unacceptable negative effects. Toxicity data from species in three trophic levels (algae, invertebrates, fish) is used to calculate the predicted no-effect concentration (PNEC). The document outlines how to determine toxicity through dose-response relationships and endpoints like median lethal concentrations and no observed effect concentrations.
Lecture toxicity testing
- 1. Marine Pollution and Ecotoxicology – 2008 Introduction to Toxicity testing of chemicals Practical course
- 2. Marine Pollution and Ecotoxicology – 2008 The role of toxicity testing in ecotoxicology Aquatic toxicity: The negative effects of a substance on the living organisms (obtained from testing on aquatic animals and plants) Degradability: The persistence of the substance in the environment (dependent on molecular chemistry of the chemical) Bioaccumulation: The accumulation of a substance in living organisms, which may or may not lead to a toxic effects (often obtained by experimenting and /or modeling or use of bioconcentration factors (BCF) or bioaccumulation factor (BAF). Toxicity is among 3 specific properties of a chemical used to describe its potential hazard to the aquatic environment
- 3. Marine Pollution and Ecotoxicology – 2008 The goal of toxicity tests To determine the level (concentration) of a chemical in the water that will cause unacceptable negative effects on the environment How do you calculate PNEC from toxicity data? PEC PNEC Risk Quotient = Remember… ERA
- 4. Marine Pollution and Ecotoxicology – 2008 In the case of aquatic ecotoxicology, preferably toxicity data should be obtained from species representing 3 different trophic levels PNEC is traditionally calculated from toxicity studies algae invertebrate fish PrinciplePrinciple How is toxicity data presented?
- 5. Marine Pollution and Ecotoxicology – 2008 Some terminologies Effects: e.g. Accumulation, Cellular, Mortality, Behaviour, Ecosystem, Physiology, Biochemical, Growth, Population, Reproduction End-point: Concentration of the chemical in the water at which a certain Level of the Effect is observed e.g. Concentration in the water at which 50% of the experimental organisms are dead in 48h or LC50 (48h) Concentration in the water at which 5% of the new born have deformations or EC5
- 6. Marine Pollution and Ecotoxicology – 2008 The best data set should include results from 3 trophic levels (algae, invertebrates and fish) Long-term end-points are preferred i.e. NOEC If no long-term data is possible or available then use short-term toxicity data i.e. LC50 or EC50. Data needed to calculate PNEC
- 7. Marine Pollution and Ecotoxicology – 2008 Available data Assessment / application factor At least one short-tern L(E)C50 from each of three trophic levels of the base-set (Fish, Daphnia and Algae) 1000 One long-term NOEC (either fish or Daphnia) 100 Two long-tern NOECs from species representing two trophic levels (Fish and/or Daphnia and/or algae) 50 Long-term NOECs from at least three species (nornally Fish, Daphnia and algae) representing three trophic levels 10 Calculation of PNEC based on available toxicity data Use of toxicity data
- 8. Marine Pollution and Ecotoxicology – 2008 General principal: Dose versus Effect relationships Dose-effect curves and how to determine NOEC Dose / exposure concentration effect individual Population Ecosystem
- 9. Marine Pollution and Ecotoxicology – 2008 Determine a dose / concentrations at which no significant toxic effect is observed How to determine toxicity Dose / exposure concentration effect No Observed Effect Concentration (NOEC)
- 10. Marine Pollution and Ecotoxicology – 2008 Toxicity of essential and non-essential substances
- 11. Marine Pollution and Ecotoxicology – 2008 How to determine toxicity Dose / exposure concentration effect Effects and End-points 1. Acute effect • Mortality End-points LC values i.e LC50 2. Chronic effects • reproduction • growth e.t.c. • species distribution • biodiversity e.t.c end-points EC values i.e. EC50 NOEC
- 12. Marine Pollution and Ecotoxicology – 2008 • Determine the LC50(24h) of copper or cadmium on artemia salina • For reporting compare and discuss the toxicity of these two heavy metals. Practical exercise