Ekotoxikologie vodních ekosystémů Úvod Tabulka 1 Rozložení vody v biosféře (podle různých autorů sestavil Wetzel« 1983) Objem X Doba v tis. km5 obnovení oceány 1 370 000 97,61 37 000 roků polární led a ledovce 29 000 2,08 16 000 roků podzemní voda (volně pohyblivá) 4 000 0,29 300 roků sladkovodní Jezera a Jiné nádrže 125 0,009 1-100 okú slaná Jezera 104 0,0 )8 10-1000 roků půdní vlhkost 67 0,005 280 dnů řeky U 0,000 09 12-20 dnů atmosférická vlhkost 14 0,000 9 9 dnů 1 km-* = ■___;_____i_____j______i_____j_____i______i_____i i i 500 1 000 km Rozloha některých velkých kontinentálních vodních nádrží (vše ve stejném měřítku): 1 jezero Athobaska, 2 Velké Medvědí. 3 Ladoga, 4 Aralské. S Balkaš, 6 Oněga, 7 Winnipeg, 8 Neusiedlerské, 9 Bajkal, 10 Velké Solné. 11 Velké Otročí, 12 Černé moře, 13 Kaspické moře, 14 jezero Čad, 15 Viktóriino, I6 Njasa, 17 Innaren. 18 Tanganjika, 19 Ženevské, 20 Vättern, 21 Titicaca, 22 Nicaragua, 23 Hořejší. 24 Michigan, 25 Huron. 26 Erie. 27 Ontario, 28 Tana, 29 Rudolfovo. 30 Mrtvé moře, 31 Balaton Ekotoxikologie ekosystémů: • Povrchových vod - Stojaté (lenitické) • Přírodní jezera, tůně • Přehrady (vodárenské, rekreační, technologické) • Rybníky, mokřady - Tekoucí (lotické) • Prameniště, potoky, řeky • Podpovrchové a podzemní vody Risk Assesment Interdisciplinary Aquatic Assesment Exposure Studies Groundwater Geohydrologist ! Surface water nvironmental chemists Fate Studies Modelers Effect Studies Field surveys Biologist reshold concentrations Toxicologists Effect Studies Aquatic toxicity lab Analytical chemistry Iah Statistician Library services Figure 1. Interdisciplinary team structure for typical aquatic assesment Chemistry Toxicology I Ecology Managerial aspects Major influences Ecosystems Risk assessment Humans Management of the environment Physiology . Biochemistry Other influences Limnology Genetics Microbiology Geology Meteorology Oceanography Mathematics ■ Modelling Komponenty oboru Ekotoxikologie vodních ekosystémů Aquatic Toxicology Integrated Processes •Toxicity testing •Chemical meaurement •Statistical analyses •Structure-activity relationships •modelling BIOLOGICAL STRUCTURE/FUNCTIONl • AQUATIC ECOLOGY • BEHAVIOR • PHYSIOLOGY • HISTOLOGY • BIOCHEMISTRY PHYSICAL FACTORS • MOLECULAR STRUCTURE • SOLUBILITY • VOLATILITY • SORPTION ENVIRONMENTAL CONCENTRATION DISTRIBUTION/FATE) CHEMICAL FACTORS • HYDROLYSIS • PHOTOLYSIS • OXIDATION/ REDUCTION BIOLOGICAL FACTORS • BIOACCUMULATlON • BIOTRANSFORMATION • 8IODEGRADATION Ekotoxikologie vodních ekosystémů je multidisciplinární věda Molecular level T J i ■ i r - 1 Celts Organs Individual organisms Populations Community Ecosystems i Increasing importance of data Increasing ease of obtaining data Increasing level of uncertainty Increasing time to complete research Present statjs of knowledg Relationships of aspects of the science of ecotoxicology and different levels of biological organisation c o Ü < o ni CZ a. o> y c CD o c CO v 0) o (T o x O Ü 1- Ä .5 ra -O O £ Dermal Food Inhalation Uptake from Site of Administration Biological Transport Metabolic Activation Other Aquatic Detoxication Reduced Toxicity Binding to Plasma Proteins CD 05 .c CL O E ca "O o o x o c c V-■ u en o ♦-* C o 2 cö J3 O concentration at Target Site (Ct) Physiological Responses Organism Adverse Effect(s) J i 1 1 1 Interaction of Toxicant at Site of Action 1 Molecular Biochemica! Response Overview of processes controlling toxicity within an organism. In the toxicokinetic phase, the organism is exposed to a substance by various routes: food, aquatic uptake, dermal, inhalation, etc. The substance is then transported within the organism and can be detoxified (leading to reduced toxicity), metabolically activated (leading to increased toxicity, or expressed directly as the original substance. In the process of reaching the target site (toxicodynamic phase, which involves probability of interaction), binding can occur to plasma proteins that reduces the blood concentration. Once reaching the target site (C,) interaction can take place leading to a molecular biochemical response (receptor interaction), which produces a cascade of physiological responses leading ultimately to observed whole-organism adverse effect(s). BIOLOGICKÉ SYSTÉMY V EKOTOXIKOLOGII Chemická látka vstupuje do živého systému a má charakteristický osud (organismus ~ další vnější prostředí) TOXOKINETIKA / TOXIKOKINETIKA - příjem / transport / distribuce / metabolismus / eliminace TOXODYNAMIKA / TOXIKODYNAMIKA - biochemické interakce s receptorovým místem Toxikologie látky na různých úrovních - molekulární, buněčná, orgánová .... organismální Ekotoxikologie - efekty na organismální úrovni se projeví na stavu populace, společenstva Table 1. Mammalian toxicology and ecotoxicology differ in many respects Mammalian toxicology Objective: to protect humans from exposure to toxic substances and materials at concentrations which are or may be associated with adverse effects Must almost always rely on animal models (e.g., rat, mouse, guinea pig, rabbit) since experimentation with humans is not feasible Species of interest (man) is known; thus degree of extrapolation is more certain Test organisms are homeothermic or warm-blooded (body temperature is relatively uniform and nearly independent of environmental temperature); thus, toxicity is predictable The dose of a test chemical usually can be measured directly and accurately, and may be administered by a number of routes. However, unless "absorbed dose" measurements are made via tissue dosimetry, the typical LD50 (e.g., oral bolus) estimate is an external or exposure dose Extensive "basic" research has been conducted; emphasis has been on understanding mechanisms of toxic action Test methods are well developed, their usefulness and limits well understood 'Organisms ;an include aquatic and terrestrial species including pia Adapted from Rand, 1991. Ecotoxicology" Objective: to protect populations and communities of many diverse species from exposure to toxic substances and materials at concentrations which ?re or may be associated with adverse effects Can experiment directly on species of concern (although there may be uncertainty on whether the most appropriate "indicator" or "sensitive" species is used) Not able to identify and test all species of concern; thus, degree of extrapolation is uncertain. Organism responses and toxicity may be different in more complex natural systems because c ^bioavailability of chemical, organic matter concentrations and other environmental interactions Test organisms (aquatic) live in a variable environment and most are Poikilothermie or cold-blooded (body temperature varies with the environmental temperature), birds and aquatic mammals being the exception; thus toxicity may not be sufficiently predictable The external or exposure "dose" is known in terms of the chemical's concentration in a medium (typically water, but also sediment and/or food) and the length of exposure to it; the actual "absorbed dose" is often determined now experimentally using bioconcentration/ bioaccumuiation and metabolism studies Much less "basic" research has been conducted, as emphasis has been on measuring toxic effects and generating media-based threshold concentration data, with an eye toward regulatory needs. More recently, emphasis has been on mechanisms of action and structure-activity relationships Many commonly used test methods are relatively new and some are formalized (standardized). However, their usefulness in many cases at predicting field impacts and protecting natural ecosystems is often uncertain . invertebrates, fish, birds, and mammalian wildlife.