Ecotoxicological Risk Assessment PDF

Ecotoxicological Risk Assessment 1. Risk and hazard 2. Chemical legislation  New chemicals  Pesticides 2. Risk assessment approaches  SSDs  Assessment factors  Ot...

Ecotoxicological Risk Assessment 1. Risk and hazard 2. Chemical legislation  New chemicals  Pesticides 2. Risk assessment approaches  SSDs  Assessment factors  Other approaches 1 Prognosis or predictive risk assessment Assessing risk of new or existing chemical Derivation of risk limits (environmental quality criteria or safe levels) based on available data 2 1  Risk = Hazard x Exposure 3 4 2  Risk = Hazard x Exposure Hazard – Intrinsic chemical property (MoA) – Qualitative (Hazard characterization) E.g. chemical is reducing fertility – Quantitative (Effect assessment) E.g. LC50, EC50, EC10, NOEC … Exposure – Quantitative measure of presence of a hazard – Exposure assessment E.g. concentration (mg/kg soil; mg/L water) Risk – Probability a negative effect will occur 5 General principle of (eco)toxicological risk assessment Chemical in the environment Exposure Effect PEC PNEC Predicted environmental (LC50/EC50/NOEC) concentration PEC/PNEC ratio = probability of effect 6 3  Legislation of chemicals: 1. New chemical substances - EU guideline (1981) - Notification required in country of introduction or use - No registration (so, no direct possibility to ban use) - Information requirement dependent on volume - REACH  started in 2008 with (re)registration of all chemicals in use - Coordination by ECHA (European Chemicals Agency) 7 REACH EU (2003) plan for a comprehensive system for Registration, Evaluation and Authorisation (and restriction) of CHemicals - Accepted by European Parliament in 2007; - Shift of responsibilities for performing risk assessment from governments to industries; - Aims at assessing risk of all chemicals in use, but also at reducing number of test animals by using Read Across, QSARs and in vitro techniques 8 4  REACH (EU 1907/2006)  Sustainable development Industry responsible for safe use of substances Authority controls compliance of industry  Priority for data collection Manufacturing / marketing according to quantity (1000 – 100 – 1 tonnes/year) CMR properties (Carcinogen;Mutagen;Reprotox) (high priority) Potential PBT/vPvB properties > 100 tonnes/year (Persistent; Bioaccumulative;Toxic / very Persistent;very Bioaccumulative) 9 REACH: main elements Registration of all substances Scope: > 1 t/yr evaluation required > 100 t/yr selective evaluation < 100 t/yr decisions for additional information proposal for authorisation proposal for restriction measures Evaluation by competent authorities Restriction measures for Authorization of certain substances of concern hazardous substances Other concern substances outside the scope of registration requirement of REACH 10 5  Tasks of Manufacturers & Importers Responsibility of Manufacturer/Importer  Data required (dependent on quantity range) physical-chemical data (eco)toxicological data emission / exposure data (also for use downstream)  Chemical Safety Assessment  Chemical for use/production on site Safety Report for intended uses downstream 11 Ecotoxicological information required Tier 1: > 1 t/yr Short-term Aquatic: algae; daphnid Tier 2: > 10 t/yr Short-term Aquatic: fish Activated-sludge respiration inhibition Tier 3: > 100 t/yr Long-term Aquatic: daphnid, fish (ELS, growth) Short-term Soil: invertebrates, microbes, plants Tier 4: > 1000 t/yr Long-term Soil: invertebrates, plants 12 6  Legislation of chemicals 2. Pesticides - Registration only when no un-acceptable risk - Harmonized at EU level since 1991  approval of active substances by EFSA (European Food Safety Authority)  regulation of formulated products by member states  environmental criteria: - persistency - groundwater protection Protection goals: - toxicity for aquatic organisms Protecting Biodiversity - toxicity for non-target arthropods and Ecosystem Services - etc. - More or less ‘fixed’ package of data required 13 Ecotoxicity tests for pesticide registration (tier 1) Birds - LD50 acute oral - LC50 (5d) feeding test Aquatic organisms - acute toxicity for algae, Daphnia and fish (48-96h, NOEC/LC50) Bees and beneficial arthropods - 24-28h LD50 acute oral and contact for honeybees - several tests with beneficial arthropods Soil organisms - toxicity for earthworms (4 wk, EC50 reproduction) - 4-6 wk inhibition of soil nitrification For products reaching soil also asked for: - toxicity to springtails (4 wk, EC50 reproduction) - toxicity to predatory mites (2 wk, EC50 reproduction) 14 7  General principle of Risk Assessment hazard Risk quotient: Ratio of dose or predicted environmental concentration (PEC) and no effect level (PNEC) Risk = hazard * exposure For an interesting video on risk: https://www.youtube.com/watch?v=PZmNZi8bon8 15 Estimating exposure Emission estimated from chemical production and use pattern Distribution estimated using box model (new chemicals) Exposure estimated using more refined models (pesticides) 16 8  Risk limits Increase of risk Unacceptable risk Maximum permissible Risk reduction level required Negligible Negligible level risk 17 Risk characterization Deriving risk limits (environmental For ecosystem quality criteria or safe levels) based on available data to protect ecosystems 18 9  Instruments for deriving ecotoxicological risk limits Toxicity test (usually performed in lab.) Aim: determination of dose-response relationships (under standardised conditions, using selected species, applying standardised methods, etc.) Test parameters: survival, growth, reproduction Results: LC50, EC50, EC10, NOEC Main question: how to estimate risk of a chemical to an ecosystem based on such laboratory toxicity data? 19 EC10 values for Cadmium toxicity to soil organisms  not all species have same sensitivity -------------------------------------------------------------------------- Group Species EC10 (mg/kg dry soil) -------------------------------------------------------------------------- Plants Raphanus sativa 6.1 Hordeum vulgare 11.4 Microbes Soil respiration 88.0 Earthworms Dendrobaena rubida 75.4 Lumbricus rubellus 8.1 Eisenia andrei 7.5 Isopods Porcellio scaber 4.5 Collembola Orchesella cincta 25.1 Mites Platynothrus peltifer 1.3 Molluscs Helix aspersa 4.5 -------------------------------------------------------------------------- 20 10  Main assumptions in ecotoxicological risk assessment 1. Functioning of the system is protected when structure (= species) is protected 2. Sensitivity of ecosystem is determined by most sensitive species 3. Sensitivity of species in an ecosystem can be described by log-logistic or other statistical distribution 4. Maximum permissible concentration (MPC or HC5) corresponds to protection of 95% of the species 21 Statistical method: Species Sensitivity Distribution (SSD) 5% ln NOEC MPC = HC5 (Maximum Permissible Concentration = Hazardous concentrations to 5% of the species) 22 11  Use of SSDs: 1. Define risk limits (backward) each point is toxicity value for different species Chosen risk level (e.g. 5%) Risk limit (HC5) 23 Use of SSDs: 2. determine risk (forward) Risk = fraction of species affected Risk: 0.6 Risk: 0.3 Sample 1 Sample 2 24 12  SSD only applicable if at least 8 taxonomic groups are represented in data set 1. Fish (species often tested salmonids, minnows, bluegills etc.); 2. A 2nd family in the phylum Chordata (fish, amphibians, etc.); 3. Crustacean (e.g., cladoceran, copepod, ostracod, isopod, etc.) 4. Insect (e.g., mayfly, dragonfly, damselfly, stonefly,midge, etc.); 5. Family in phylum other than Arthropoda or Chordata (e.g., Rotifera, Annelida, Mollusca, etc.); 6. Family in any order or phylum not already represented; 7. Algae; 8. Higher plants. 25 Restrictions to the risk assessment method 1. Only applicable to toxicity data of same type  either NOEC/EC10, EC50 or LC50 values  when using LC50s or EC50s extra assessment factor(s) needed 2. For reliable calculation at least 8 values needed (but preferably 10-15) 3. Test organisms should be representative for ecological function, body design, physiology and route of exposure  so at least 8 taxonomic groups should be included  When < 8 taxonomic groups  extra assessment factor needed 4. Only applicable to species 26 13  When not enough data available, estimation of MPC or risk limit by: 1. Applying assessment factors (EPA method) 2. Applying the Equilibrium Partitioning (EqP) method to derive limits for soil based on data on aquatic organisms 3. Applying QSARs to estimate toxicity data or sorption values 27 EPA method Application of assessment factors (AF), e.g. for determination of MPC/PNEC for aquatic ecosystems: ----------------------------------------------------------------------------------- Available information Assessment factor ----------------------------------------------------------------------------------- At least one acute L(E)C50 for acute toxicity 1000 (=10*10*10)# One long-term NOEC (fish or daphnid) 100 Two long-term NOECs 50 Long-term NOEC for ≥3 species 10 SSD 5-1* Field data or model ecosystems 5-2* ----------------------------------------------------------------------------------- # factors 10 for acute  chronic, 10 for one  many species, 10 for lab  field *exact factor judged case-by-case (expert judgement) 28 14  Equilibrium Partitioning Concept (EqP) (main assumption: water is main route of exposure, also for soil organisms) Kd Soil or sediment (pore)water EC50/NOEC organism MPCsoil/sediment = MPCwater * Kd 29 Risk characterization SSDs AF method EqP Risk limits 30 15  Learning goals After this lecture you are able to: Explain the difference between hazard and risk Describe the main requirements for ecotoxicological data in regulatory frameworks for chemicals and pesticides Explain how safe levels of chemicals are derived from available toxicity data Understand the way Species Sensitivity Distributions (SSDs) are applied Explain the pros and cons of using SSDs versus the application of Assessment Factors for deriving risk limits 31 16