Ecotoxicology Part 1 - Introduction Ludek Blaha + ecotox colleagues Global anthropogenic threats ? A safe operating space for humanity & the nine planetary boundaries Rockstrom et al. 2009 (Ecology and Society 14(2): 32; Nature 461, 472-475) 1996 - Chemicals in the environment Do you believe that chemicals in products sold to consumers have been proven safe? Think again most chemicals in modern use have simply not been tested for their impacts on human, even very basic effects. … what about the effects in nature, then ? How we stand 20 years later? Environmental pollution Examples and ecological cosequences Contamination of water - chemicals ? Degradable „nontoxic“ organic material + nutrients / fertilizers (N/P) „Other“ chemicals HO OH HO OH HO OH Major anthropogenic threats – example: waters DirectIndirect Impacts • Loss of biodiversity Major impacts Changes in biodiversity Changes in biodiversity NATURE (2012) 482: 20 • Loss of biodiversity Major impacts • Impairment of ecosystem services – Unbalanced water cycles • Water scarcity • Draughts/floods – Impaired water quality • Drinking waters • Bathing waters • Toxicants in food chain – Shrinking of food supplies • Direct  lowering fish amounts • Indirect  crop yield Impacts on fish  decreased crop yields NATURE (2005) 437: 880 Impacts on biota  global effects Mixing oceans  cooling the atmosphere [Nature 447, p.522, May 31, 2007] Marine life supplies up to 50% of the mechanical energy required worldwide to mix waters from the surface to deeper cool layers [Dewar, Marine Res 64:541 (2006)] [Katija a Dabiri, Nature 460:624 (2009)] Ecotoxicology assessment o hazards and risks of chemicals in ecosystems Assessment of chemical hazards …to… Humans Other organisms (TOXICOLOGY) (ECOtoxicology) • Aim: to maintain the natural structure and function of ecosystems • Definitions:  ecotoxicology is concerned with the toxic effects of chemical and physical agents on living organisms, especially on populations and communities within defined ecosystems; it includes the transfer pathways and their interactions with the environment  science of contaminants in the biosphere and their effect on constituents of the biosphere, including humans’ (Newman & Unger, 2002)  science that provides critical information on effects of toxic compounds on living organisms which SERVE various practical aims (environmental protection) ECOTOXICOLOGY by definition CHEMICAL ENTERS THE ENVIRONMENT Bioavailable fraction “EXPOSURE” acute chronic Toxicokinetics biotransformation bioactivation excretion / sequestration Target site “EFFECT” LEVELS, FATE, PROCESSES CHEMICAL ENTERS THE ORGANISM biomonitoring Ecotoxic effects Escher, B. I., Behra, R., Eggen, R. I. L., Fent, K. (1997), "Molecular mechanisms in ecotoxicology: an interplay between environmental chemistry and biology", Chimia, 51, 915-921. Ecotoxicology - from molecules to ecosystems … and backwards From ecosystems  down the mechanisms From mechanisms (molecules)  up to effects and ecosystems OR ? 1962 © Patuxent Wildlife Refuge, MA, USA http://www2.ucsc.edu/scpbrg/ Bitman et al. Science 1970, 168(3931): 594 Biochemistry bird carbonate dehydratase In vivo: shell thinning In situ: bioaccumulation -> bird population decline 1) From molecules to individuals MECHANISMS OF TOXICITY 2) From molecules to individuals - AOPs ADVERSE OUTCOME PATHWAYS Ethinylestradiol HO OH Binds to ESTROGEN RECEPTOR Target genes - Proliferation/Apoptosis (sexual organs) - Synthesis of egg yolk (fish, amphibia) Effects - Females: reproduction regulation - Males: feminization (+ e.g. cancer promotion, development, immunomodulation) AOP Example: ethinylestradiol Kidd, K.A. et al. 2007. Collapse of a fish population following exposure to a synthetic estrogen. Proceedings of the National Academy of Sciences 104(21):8897-8901 Controls +Ethinylestradiol 5 ng/L (!) 7 years HO OH • Molecular  Nonspecific effects  Hydrophobic interactions with phospholipid membranes (baseline = narcotic toxicity)  Direct reactivity: electrophilic compounds  nucleophilic organism (e.g. oxidation of PROTEINS, lipids (membranes), DNA …)  Specific effects  Activation of ER, AR and other „nuclear receptors“  Inhibition of enzymes (e.g. CN- inhibits hemes in mitochondria/hemoglobin, insecticides …) Effects at different levels - molecular • Cellular  Effects on structure  Effects on metabolism (maintenance)  Effects on regulation Changes in functions (e.g. Ethinylestradiol) Repair, survival, growth Death (apoptosis or necrosis) Proliferation Differentiation Effects at different levels - cellular • Organism level – important in ecotoxicology (see Bioassays)  Effects on structure  Effects on metabolism (maintenance)  Effects on regulation Changes in functions (e.g. Ethinylestradiol) Repair, survival, growth Death Proliferation = Reproduction Effects at different levels - ORGANISM 3 key apical endpoints (reflected e.g. in regulations) Metabolism Control, Interactions with environment Defence against pathogens predators … Defence against toxicants Energy hv food Losses heat faeces Life (maintenance) Growth to sexual maturity Reproduction Chemical stress Metabolism Control, Interactions with environment Defence against pathogens predators … Defence against toxicants Energy hv food Losses heat faeces Life (maintenance) Growth to sexual maturity Reproduction Chemical stress Chemical stress  energy re-allocation  „insufficient“ resourses elsewhere Metabolism Control, Interactions with environment Defence against pathogens predators … Defence against toxicants Energy hv food Losses heat faeces Life (maintenance) Growth to sexual maturity Reproduction Chemical stress Chemical stress + ... another stress (food scarcity) • Population (… all the organisms that both belong to the same group or species (i.e. can sexually reproduce) and live in the same time within the same geographical area)  Effects on structure  elderly vs. young, males vs. females  Effects on maintenance & growth  Natality, mortality, reproduction fitness Effects at different levels • Community & Ecosystem (… a group of interacting living organisms sharing a populated environment)  Effects on structure  Loss of species, loss of biodiversity  Effects on functioning  (including „ecosystem functions“) Effects at different levels • Ecotoxicology as a science with close links to practical environmental protection – Understand the importance and links between BIODIVERSITY and ECOSYSTEM SERVICES • Understand keywords such as – Exposure – Bioavailability – Toxicokinetics – Toxicodynamics • From molecular events to higher levels – Be aware of different biological levels - from molecules to communities – Know examples of effects at these different levels – Know example(s) of „Adverse Outcome Pathway(s)“ WRAP UP … take home message