1212570_28446780.jpg logo_mu_cerne.gif ‹#› RECETOX, Masaryk University, Brno, CR holoubek@recetox.muni.cz; http://recetox.muni.cz 6th Summer School of Environmental Chemistry and Ecotoxicology Brno, Czech Republic, 28 June – 03 July, 2010 Fate of toxic compounds in the environment Ivan Holoubek, Jana Klánová SC_logo (2)_transparen kytka 1212570_28446780.jpg logo_mu_cerne.gif ‹#› 2 RECETOX - EU Centre of Excellence - http://recetox.muni.cz/ SC Regional POPs Centre for Central and Eastern Europe 1212570_28446780.jpg logo_mu_cerne.gif ‹#› logo_OP_VaVpI_EN CEITEC_Kampus_MU_v01 The building of facilities and research within the project CETOCOEN is funded by the European union and Ministry of Education, Youth and Sports of Czech republic. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› http://recetox.muni.cz RECETOX research team 15 teachers and professors 20 Ph.D. researchers 50 Ph.D. students 10 senior researchers and post-docs 6 technical and administrative stuff I represent a team of the Centre RECETOX – round 20 scientists, more than 50 PhD students and 30 MSc students 1212570_28446780.jpg logo_mu_cerne.gif ‹#› RECETOX Toxic Substances in the Environment Environmental Fate Harmful Effects Ecological and Human Risk Assessment Environmental Policy and Management Data Evaluation and Interpretation International Conventions – Stockholm Convention on POPs The RECETOX research is focused on the fate and biological effects of toxic substances in the environment. It supports – among others - implementation of international conventions on chemical substances like the Stockholm Convention on Persistent Organic Pollutants. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Study of the fate and harmful effects of environmental toxic compounds VGAutospecMphoto1 Koncentrace_PAHs Outstanding equipment allows top research in the field covering both, controlled laboratory and field studies. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Persistent organic pollutants ÄPersistent ÄBioaccumulation ÄToxicity ÄLong-range transport oteplovani_i Deponie Grube Antonie 1975 Persistent organic pollutants are until now the main subject of our scientific interest. These substances represent long-term problem which is connected with the production, application, disposal of many chemicals. These pollutants can be presented in the environment for long time, can be accumulated in sediments and soils and fatty tissues of man and wildlife, they have a very broad spectrum of harmfull effects and can be transported from the production or application sites to the regions where never been produced or used (polar regions, high mountains). We can find huge amounts of obsolete waste of these chemicals round the Globe, but on the other hand trace contamination of human and wildlife which can represent very serious problems. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Study of impacts of global changes to the fate and effects of toxic environmental pollutants Ice flowers ice5 Photochemistry and fate of POPs polar areas These pollutants can be transported to vulnarable arctic environments, can be cumulated there for long time. Our research there is focused on phototransformation in the polar snow and ice and the potential effects of their mobilization due to the global warming. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Bioassays for acute and chronic toxicity – air, water,soil Hormonally active xenobiotics in waste waters Blue-green algal (cyanobacterial) toxins Ecotoxicology and harmull effects of pollutants soutok ZELIVKA9_99 Estradiol types_of_contraceptive_pill Our ecotoxicology division develops and uses series of biological tests to study toxic impacts of these chemicals on both aquatic and soil organisms. Other part of research activities also covers the problem of nutrient-polluted waters and carcinogenic toxins produced in blue-green algal water blooms. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› ÄInternational conventions and programmes ÄMonitoring on the regional and local scales ÄEnvironmental chemistry and ecotoxicology ÄHuman and ecological risk assessment ÄCo-operation with government, regional and local authorities and industry ÄEducational activities RECETOX activities Persistent, bioacummulative and toxic substances – Relationship between their environmental levels and their biological effects – ecological risk assessment 1212570_28446780.jpg logo_mu_cerne.gif ‹#› RECETOX Educational programme Masaryk University Faculty of Science 8 other faculties Chemistry + 4 other sections Biology RECETOX + 5 others Faculty of Science Chemistry Biology + 4 others Environmental chemistry Ecotoxicology Mathematical Biology Structure Education RECETOX Environmental chemistry Ecotoxicology Mathematical Biology Ph.D. M.Sc. Bc. M. Sc. Bc. M.Sc. Bc. CBA RECETOX Education 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Ecological risk assessment Environmental chemistry Ecotoxicology RECETOX Conceptual approaches 1212570_28446780.jpg logo_mu_cerne.gif ‹#› ÄFate concept: physical, chemical, biological mechanisms ÄProperties, abiotic & biotic degradation mechanisms Fate of toxic compounds in the environment 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Hippocrates (460-377 BC) scientist-hippocrates-mb-l “Whoever wishes to investigate medicine properly should proceed thus…We must also consider the qualities of the waters, for they differ from one another in taste and weight, so also do they differ much in their quality” So… Hippocrates appreciated the significance of human health in context of the characteristics of the natural environment Chemicals in the environment: nothing new…. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Cause - effect paradigm: nothing new…. nWhat is there which is not a poison? n ÄAll things are poison and nothing without poison. Ä ÄSolely the dose determines that a thing is not a poison.’ n 2 Paracelsus (1493 - 1541) 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Metabolites Pharmaceuticals antibiotics, betablockers, anti-epileptics, analgetics) ~ 50000 producs, ~ 2900 effective substances Human care products (cosmetics, perfumes (~300), chemicals for hair bleaching and permanents, UV-filters) (n=???) Pesticides (herbicides, insecticides,fungicides…) ~ 1004 effective substances registered) Industrial chemicals ( ~ 80000 registered by EPA, ~ 4000 neurotoxins) Tensides, detergents (~ 800 substances) R. Triebskorn Nowdays environmental chemicals 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Subject of interest POPs = Persistent organic polutants PTS= Persistent toxic substances PBTs = Persistent, bioaccumulative and toxic substances 1212570_28446780.jpg logo_mu_cerne.gif ‹#› POPs (Persistent organic polutants) God created 90 elements, man round 17, but Devil only 1 – chlorine (Otto Hutzinger) corner1 JThe group of most fascinating pollutants (Kevin C. Jones) LGhost of the past (Terry Bidleman) 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Environmental fate of chemicals 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Environmental chemistry and photochemistry 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Environmental interface 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Systems, environmental system ÄIsolated ÄClosed ÄOpened ÄOpened 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Environmental fate of POPs ? How well do we understand the fate of POPs ? To give you a better picture of the situation with wildlife at the end of the last century, I would like to take you on a kind of global trip. For this we selected a number of wildlife species in the Northern Hemisphere. I realize that within the short time available here I can not be complete and we have chosen case studies with which we ourself are most acquainted with. So we had to make a selection, hoping that it would be a fair representation for the wildlife situation that we are going to cover in various parts of the world. For this we have chosen Seals in the Baltic and North Sea in North Western Europe, Cormorants and Common Tern in the Rhine and Meuse estuaries, Bald Eagles in the Great Lakes, Blue Herons in British Columbia and Albatrosses on Midway Island in the Pacific 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Environmental fate of POPs ? Fate of POPs – environmental transport and transformations Study of environmental processes: ÄPhysical-chemical properties of POPs ÄEnvironmental properties ÄEnvironmental distribution To give you a better picture of the situation with wildlife at the end of the last century, I would like to take you on a kind of global trip. For this we selected a number of wildlife species in the Northern Hemisphere. I realize that within the short time available here I can not be complete and we have chosen case studies with which we ourself are most acquainted with. So we had to make a selection, hoping that it would be a fair representation for the wildlife situation that we are going to cover in various parts of the world. For this we have chosen Seals in the Baltic and North Sea in North Western Europe, Cormorants and Common Tern in the Rhine and Meuse estuaries, Bald Eagles in the Great Lakes, Blue Herons in British Columbia and Albatrosses on Midway Island in the Pacific 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Environmental fate of POPs ? Fate of POPs – environmental transport and transformations Study of environmental processes: ÄLaboratory experiments ÄField experiments ÄMonitoring ÄModelling To give you a better picture of the situation with wildlife at the end of the last century, I would like to take you on a kind of global trip. For this we selected a number of wildlife species in the Northern Hemisphere. I realize that within the short time available here I can not be complete and we have chosen case studies with which we ourself are most acquainted with. So we had to make a selection, hoping that it would be a fair representation for the wildlife situation that we are going to cover in various parts of the world. For this we have chosen Seals in the Baltic and North Sea in North Western Europe, Cormorants and Common Tern in the Rhine and Meuse estuaries, Bald Eagles in the Great Lakes, Blue Herons in British Columbia and Albatrosses on Midway Island in the Pacific 1212570_28446780.jpg logo_mu_cerne.gif ‹#› soil Soil can be a source or sink of POPs Air-surface exchange Direct applications Physical mixing – ‘dilution’ with depth Biodegradation ‘Occlusion’ K. C. Jones We have always said that soil can be a source or a sink for POPs, depending on atmospheric concentration (and also properties of the soils and the POP in question aswell as ambient temperature). It looks from the results that I’ve just shown that the soil holds on to PCBs and makes them no longer available for exchange with the atmosphere. But soil concentrations reflect usage / air concentrations… Let’s have a look at al the different uptake and loss mechanisms of POPs in the soil… - POPs can be added to the soil directly of through air-surface exchange - Occlusion – formation of bound residues - biodegradation - not many studies have looked at this. - Physical mixing to deeper layers so that air-surface exchange cannot take place 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Risk assessment Exposure Atmospheric Deposition Erosion & Runoff Untreated discharges Predicted Exposure Concentration (PEC) Effects bosmina FISH Laboratory (and field) studies Ecotoxicity tests sample56 lab2 Predicted No Effect Concentration (PNEC) faCTORY1 WWTP j0173962 EUSES 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Three Types of Processes ÄPhase partitioning: uDescribed by partition coefficients (Henry‘s law constant, octanol-water partition coefficient, etc.) and intermedia mass transfer coefficients ÄDegradation: uDescribed by first-order rate constants, representing biological and chemical degradation ÄTransport: uDescribed by air and water flow velocities or macroscopic eddy diffusion coefficients 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Phases in the Atmosphere nWhat phases do organic chemicals associate with in the atmosphere? n ÄGas phase ÄParticulate matter ÄWater ÄIce/Snow 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Surfaces in the environment nWhich surfaces are important for exchange of organic chemicals with the atmosphere? n ÄWater ÄSoil ÄVegetation ÄSnow/Ice 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Velocity of losses of the chemical in environmental compartments can be described by the equation of the 1. order: d[A] / dt = - kT * [A] . . ln [A0] / [A] = kT * t If [A0] / [A] = 2, t = const., then: t1/2 = ln 2 / kT cA in time t = 0 cA after time t Half life – characteristics of the pollutant persistence in environmental compartments under specific conditions Environmental persistence 1212570_28446780.jpg logo_mu_cerne.gif ‹#› The ability to resist degradation in various media, e.g. air, soil, water, sediment, measured as half-life of the substance in the medium. Persistence reflects the ability of the substance to resist physical, chemical or biological degradation. The overall persistence of a chemical in the environment depends on how it is emitted to the environment (i.e. to air, water, or soil) and on how it subsequently migrates between media. The implication is that a substance may be quite short-lived if discharged to air, but long lived if it is discharged to water. Furthermore, a long half-life in a medium may be relatively inconsequential if the substance is not emitted to that medium or is likely to transfer to it. For example, an accurate half-life for reaction in air may not be needed for a relatively involatile chemical which is unlikely to evaporate into the atmosphere. Environmental persistence 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Persistence is described by half-live (t1/2), when the concentration of compound decreases on the half of original amount in given environmental compartments – after 5 cycles the level decreased on 3 % Waters - t1/2 = 6 days – during 1 months; if t1/2 = 70 days, removal during ca 1 year Environmental persistence 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Persistence under environmental conditions depends: Äproperties of compound Äproperties of environmental compartments: - sun irradiation - concentrations of OH radicals - composition of microbial communities - temperature Environmental persistence 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Volatility Chemicals with a volatility of less than 1000 Pascals are considered as a POPs. The volatility criterion is applied together with persistence in air, and/or data on presence in remote regions. It should be noted that even chemicals with a low to very low volatility may be transported over long distances in sufficient quantities to cause risks to human health and the environment in remote regions. Velocity of volatilization – VV [mol.l-1.hod-1]: VV = dCW / dt = kVw*CW Water concentration [mol.l-1] Velocity constant of volatilization [hod-1] 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Henry’s Law Constant H = p/CW P = partial pressure, Pa CW = water concentration, mol/m3 KAW = CA/CW = air-water partition coefficient = H/R*T Sometimes KAW is called the dimensionless Henry’s Law constant, H’ 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Vapour pressure (VP) 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Water solubility (WS, S) 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Partition coefficient n-octanol-water (KOW, P) Partition coefficient n-octanol-water KOW – the ratio of the concentration of a solute between water and octanol as a model for its transport between phases in a physical or biological system: KOW = COW / CW Because the n-octanol is a good surrogate phase for lipids in biological organisms, a KOW represents how a chemical would thermodynamically distribute between the lipids of biological organisms and water. It further represents the lipophilicity and the hydrophobicity of the chemicals. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Partition coefficient n-octanol-water (KOW, P) 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Transfer of compound cross the interface octanol – air can be described by Whitman two-resistance coefficient of mass transfer (MTC), which used the conception of two resistance – in boundary layers of octanol and air. Mass transfer if directed by molecular diffusion and the result is slower diffusion. Overall mass transfer coefficient derived from particular MTC: 1 / k = 1 / kA + 1 / (kO * KOA) Partition coefficient n-octanol-air (KOA) 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Environmental equilibria 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Environmental equilibria 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Equilibrium air - water 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Exchange Processes nWhat processes can transfer organic chemicals from the atmosphere to surfaces? n ÄDeposition of water (wet deposition of dissolved chemical) ÄDeposition of ice/snow ÄWet deposition of particulate matter ÄDry deposition of particulate matter ÄGaseous deposition 1212570_28446780.jpg logo_mu_cerne.gif ‹#› nWhat processes can transfer organic chemicals from surfaces to the atmosphere? n ÄAerosol generation ÄVolatilisation Exchange Processes 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Phase Distribution in the Atmosphere nBetween the gas phase and water: n ÄAccording to the Henry’s Law constant (KAW=H/RT) ÄDependent on temperature ÄEquilibrium generally reached, but perhaps not locally ÄSurface adsorption can contribute to levels in very small water droplets (fog) 1212570_28446780.jpg logo_mu_cerne.gif ‹#› nBetween the gas phase and particulate matter: n ÄCombination of dissolution, surface adsorption, and absorption in organic matter ÄAbsorption believed to dominate for POPs, described by: n n KPA = VP * fOC * KOC/KAW n ÄTemperature dependent ÄEquilibration believed to be rapid, but not much experimental evidence Phase Distribution in the Atmosphere 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Phase Distribution in the Atmosphere (III) nBetween the gas phase and snow: n ÄSurface adsorption ÄDependent on surface area of snow (0.01-0.1 m2/g) ÄLittle experimental evidence on magnitude and kinetics of partitioning 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Two resistent concept of mass transfer of a chemical between air and water 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Soil and atmospheric processes which determine volatilization of soil applied chemicals 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Chemical compounds are transported from the atmosphere on water or soil by atmospheric deposition. Atmospheric deposition: Äwet Ädry Wet atmospheric deposition – sum of rain washing (rain out) a washout (under clouds) process. Dry atmospheric deposition – sum of aerosol deposition and gas absorption. Dry and wet atmospheric deposition 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Dry and wet atmospheric deposition 1212570_28446780.jpg logo_mu_cerne.gif ‹#› free vapour absorption liquid-surface adsorption vapour-surface adsorption aerosol core liquid-like layer non- exchangeable material Particle - gas interactions 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Particles in the Atmosphere Whitby, K., Sverdrup, G., Adv. Environ. Sci. Technol. 10, 477 (1980) 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Rainout, washout and aerosol deposition – one direct advection transport processes – chemicals are removed from atmosphere to waters and soils – this mechanism is realized if compound has a higher fugacity in water or soil. Absorption of gases has a diffusive mechanism – absorption of compound from gaseous phase by water or soil is realized in the fugacity of chemical is higher in air than in water or soil. If the fugacity in water or soil is higher, the result is a opposite – the volatilization is coming. Dry and wet atmospheric deposition 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Transport of chemical compounds from air to the waters and soils by dry deposition can be described resistance. Velocity of deposition vd indirectly depends on the three resistances which represent three various steps of process: vd = 1 / (ra + rb + rc) Where: ra = atmospheric resistance rb = resistance of laminar layer rc = resistance of surface covering ra, rb – depend on atmospheric stability rc - depends on chemical composition and physical structure of acceptor surface and deposited material. Dry atmospheric deposition 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Sorption In the interface of two phases the transition area is created the concentrations of individual components are generally different than inside the phases. The different properties if inter-phase are done by the existence of inter-surface powers. If based on the effect of these powers, the concentration of one component increased in the comparison with the concentrations inside the phase – this cummulation is described as a sorption. The contact of gases or solutions with solid phase is described as adsorption. Adsorbent – adsorbate. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Surfaces Electric double-layer Iont exchange 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Sorption Colloids Surfaces 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Two types of adsorption: Physical – van der Waals intermolecular powers act between the solid phase and molecules of adsorbate: ÄBond is relatively weak, reversible ÄConsists from more than 1 layers ÄAdsorption energy - 0,3 – 3 kJ.mol-1 ÄAdsorption equilibrium is constituted relatively quickly ÄExample: adsorption of gases on active carbon Physical sorption 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Chemical – nature are powers much more stronger, comparable with the powers which are leading to the production of chemical compounds: ÄProduction of surface compound ÄOne layer ÄAdsorption energy – 40 – 400 kJ.mol-1 ÄIn the range of low temperature – mostly irreversible, we need for removal chemisorbed gas from the surface higher temperature ÄAdsorption of ions – electrostatic powers – electro-adsorption. Adsorption is not a simple process – combination of interactions. Chemical sorption 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Freundlich isotherm: Adsorption isotherms log CS = log Kd + n * log CW 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Sorption 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Equilibrium water – solid phase (sediments, suspended sediments, soils) 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Atmospheric transport ÄSubstantial transport of the volatile and semi-volatile POPs ÄSignificant seasonal variations for some POPs reflecting differences in usage, transport mechanisms and degradation (e.g. trans-chlordane, g-HCH) ÄChange in congener/isomer distribution due to differences in deposition and photo-chemical processes (e.g. PCB, HCH and chlordane profiles) 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Long-range atmospheric transport nPersistent Organic Pollutants (POPs) n nMainly due to LRT, but also some regional use and releases of pesticides and industrial chemicals (e.g. PCBs and HCB) S06079-1 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Principles and consequences of long-range transport ÄDistribution and transport of stable contaminants across long distances ÄMajor distribution routes: atmosphere, oceans, rivers and sea ice ÄTransport and accumulation in pristine ecosystems ÄUltimately, significant impact on indigenous people DSC00024 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Long-range transport elucidation Evaluation tools ÄEstimation of meteorological, hydrological, oceanographic conditions during the transport event (e.g, air mass back trajectories) ÄPhysico-chemical properties and characterisation ÄCompound pattern elucidation ÄAssessment of concentration levels including ratio evaluation between different contaminant types ÄTransport and fate modeling 2000040100 1212570_28446780.jpg logo_mu_cerne.gif ‹#› The „Grasshopper Effect“ 1212570_28446780.jpg logo_mu_cerne.gif ‹#› PTS Transport Pathways Äpersistence increases the relative importance of transport relative to transformation in controlling a contaminant's fate Ädistribution characteristics leading to significant presence in different environmental media (air, water, soil) atmospheric transport (gas phase, particles, cloud water) transport by migratory animals oceanic transport (dissolved phase, particles) riverine transport (dissolved phase, particles) anthropogenic transport (products, waste) F. Wania 1212570_28446780.jpg logo_mu_cerne.gif ‹#› “grass-hopping” high latitudes deposition > evaporation low latitudes evaporation > deposition mid latitudes seasonal cycling of deposition and evaporation long range atmospheric transport degradation and permanent retention long range oceanic transport Temperature gradients in space in combination with atmospheric mixing will favour gradual transfer from warm to cold regions on both global and regional scales Because rates of deposition and evaporation are temperature-dependent, hopping is enhanced by periodic temperature changes Long-range transport of PTS, e.g. HCB F. Wania 1212570_28446780.jpg logo_mu_cerne.gif ‹#› The Chemical Partitioning Space gas phase KOA KAW KOW aqueous dissolved phase organic dissolved phase defined by equilibrium phase partition coefficients between air, water and octanol 3 4 5 6 7 8 9 10 11 12 -4 -3 -2 -1 0 1 2 3 log KOA decreasing volatility 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Biaccumulation – basic definitions The process by which the chemical concentration in an (aquatic) organism achieves a level that exceeds that in the water (soil), as a result of chemical uptake through all possible routes of chemical exposure (dietary absorption, transport across the respiratory surface, dermal absorption, inhalation). Bioaccumulation takes place under field conditions. It is a combination of chemical bioconcentration and biomagnification. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Biaccumulation 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Bioconcentration – basic definitions The process in which the chemical concentration in an (aquatic) organism exceeds that in water (soil) as a results of chemical exposure to (water)borne chemical. Bioconcentration refers to a condition, usually achieved under laboratory conditions, where the chemical is absorbed only from the water (soil) via the respiratory surface (e.g. gills) and/or the skin. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Biomagnification – basic definitions The process in which the chemical concentration in an (aquatic) organism exceeds that in the organism´s diet, due to dietary absorption. The extent of chemical biomagnification in an organism is best determined under laboratory conditions, where organisms are administered diets containing a known concentration of chemical, and there is no chemical uptake through other exposure routes (e.g. Respiratory surface, dermis). Biomagnification also can be determined under field conditions, based on chemical concentrations in the organism and its diet. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Biomagnification 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Bioaccumulation 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Bioaccumulation 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Elimination process Analogically of the process of intake also the process of elimination can be directed mainly by passive diffusion and active transport. Main part of hydrophobic compounds are eliminated by passive diffusion to water or excrements. Concentration of compound is also diluted by the process of organism growing. Other possible elimination process is breathing or transfer of chemicals to the eggs. Biotransformations, especially of mote hydrophilic compounds is other possible proces of elimination of compound from organism. Fish Growing Intake Reproduction kr Elimination ke Biotransformation km Bioaccumulation, biomagnification 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Intake and elimination of compounds by aquatic organism: Exposure by pollutant Exposure is finnished Elimination: dC0/dt = - ke * C0 C0 Time Intake: dC0 / dt = kw * Cw – ke * Ce Equilibrium: dC0 / dt = 0 Bioaccumulation, biomagnification 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Bioaccumulation 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Bioaccumulation factor (BAF) is the ratio of the chemical concentration in an organism (CB) to the concentration in water (CW): BAF = CB / CW Because chemical sorption to particulate and dissolved organic matter in the water column can reduce substantially the fraction of chemical in water that can be absorbed by aquatic organisms, the BAF also can be expressed in terms of the freely dissolved chemical concentration (CWD): BAF = CB / CWD Bioaccumulation factor 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Bioconcentration factor (BCF) is the ratio of the chemical concentration in an organism (CB) to the concentration in water (CW): BCF = CB / CW BCF, like the BAF, also can be expressed in terms of the dissolved chemical concentration (CWD): BCF = CB / CWD The exposure under steady state conditions is considered. Bioconcentration factor 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Biomagnification factor (BCF) is the ratio of the chemical concentration in an organism (CB) to the concentration in the organism´s diet (CW): BMF = CB / CD Biomagnification factor 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Relationship between BCF and log KOW 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Bioaccumulation in terrestric vegetation 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Relationships among the environmental parameters Compartment Parameter Compartment Water (more mobile) KOW Soil, sediment, animals (less mobile) KOC KD BCF WS Water H Air VP 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Bioavailability processes can be defined as the individual physical, chemical and biological interactions that determine the exposure of organisms to chemicals associated with soils and sediments. Bioavailability – key issue K. Semple 1212570_28446780.jpg logo_mu_cerne.gif ‹#› In both soil and sediment, processes that determine exposure to contamination include release of a solid-bound contaminant (A) and subsequent transport (B), transport of bound contaminants (C), uptake across a physiological membrane (D), and incorporation into a living system (E).(A, B, C, D – bioavailability processes) Bound contaminant Released contaminant Association Dissociation A D C D Biological membranes Adsorbed contaminants in organism Site of biological response E Bioavailability Ehlers and Luthy, 2003 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Chemicals in the living organisms 176 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Toxic effects of chemical compounds 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Environmental transport and transformation processes 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Chemical transformation processes Processes – reactions, when attend to the disappearance of chemical bonds and origin of new ones: ÄAbiotic (without present living organisms) – the result is a new compound: •chemical (redox, hydrolysis), •photochemical: §direct photolysis (direct absorption of light) §indirect photolysis (reaction with reactive particles – free radicals, singlet oxygen) ÄBiotic: •biological (microbial degradation) – it can leads to the environmental mineralisation. 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Chemical transformation processes 1212570_28446780.jpg logo_mu_cerne.gif ‹#› ÄOne or more reactions of given compound is ongoing under given environmental conditions and what reaction products can be expected ? ÄWhat is a kinetic of different reactions ? ÄHow is a effect of important environmental variables such as a temperature, pH, redox conditions, ionic power, presence of other dissolved compounds or concentration and type of solid phases on the behaviour of given compound during the transformation process ? For answering of these questions - we need to the reaction mechanism of compound transformation. Chemical transformation processes 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Reaction of the first order: d[A] / dt = - k * [A] Integration from [A] = [A]0 in time t = 0 to [A] = [A]t in time t = t: [A]t = [A]0* e-kt Half-life of the 1.st order reaction: t1/2 = ln 2 / k = 0,693 / k Reaction of the second order: d[A] / dt = - k´ * [A] * [B] t1/2 for losses of compound A = ln 2 / k´[B] Velocity constant of the 1. order Chemical transformation processes – reaction kinetics 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Nucleophilic substitution of halogens on the saturated C atom SN2 mechanism SN1 mechanism Hydrolysis 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Process, where electron-deficient particle (oxidant) receives electrons from substance, which is oxidized. Examples of oxidants present under environmental conditions in sufficient high concentrations and react quickly with organic substances: Äalkoxy radicals (ROŸ) Äperoxy radicals (ROOŸ) Ähydroxyl radicals (OHŸ) Äsinglet oxygen (1O2) Äozone (O3) Most of these oxidants are directly or indirectly generated from compounds after interaction with sun light via excited form of molecule (photochemical excitation). Oxidation is a main transformation process for the most or organics in troposhere and surface waters. Oxidation 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Oxidation 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Reduction 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Reduction 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Photochemical transformation processes 1212570_28446780.jpg logo_mu_cerne.gif ‹#› radio microwave infrared visible UV X-rays g-rays E g (nm) 1012 1010 108 106 104 102 1 10-2 10-4 Photochemistry 1000 800 600 400 200 infrared visible a b c ultraviolet g (nm) Photochemical transformation processes 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Photochemical transformation processes 1212570_28446780.jpg logo_mu_cerne.gif ‹#› How well do we understand the sources, transport and ultimate fate of POPs in ice ? Photochemistry of organic pollutants in solid matrices 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Chlorobenzene - unique transformation pathways in ice matrix Klán P., Ansorgová A., Del Favero D., Holoubek I. Tetrahedron Lett. 2000, 41, 7785-7789. Ice Photochemistry of organic pollutants 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Toxicity increases in ice upon photolysis Induction of dioxin-like toxicity by photoproducts of p-chlorophenol in water ice (comparison with the toxic potency of 2,3,7,8-TCDD) Blaha et al., 2004 1212570_28446780.jpg logo_mu_cerne.gif ‹#› pozadi3 Environmental consequences Klán P., Holoubek I.: Chemosphere, 2002, 46, 1201-1210 1212570_28446780.jpg logo_mu_cerne.gif ‹#› OH radicals in the atmosphere W.-U. Palm 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Biodegradation 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Biodegradation 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Types of biotransformation reactions Two types: Phase I – non-synthetic reactions – hydrolysis, oxidation, reduction – molecules of compound are changed by introducing of polar group (-OH, -COOH, -NH2) – products are reactive compounds easily conjugated in the phase II Phase II – synthetic reactions – conjugation – production of conjugates such are glucuronides, sulphates, acetyl and glutathion conjugates – results is conjugated product which can be eliminated by excrements Mechanisms of biotransformation of the xenobiotics in the living organisms 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Mechanisms of biotransformation of the xenobiotics in the living organisms Environment Xenobiotics in organism Superhydrophobic Hydrophobic Polar Hydrophilic Accumulation in fatty tissue Phase I Bioactivation or detoxication Oxidation, reduction, hydrolysis Phase II Bioactivation or detoxification Conjugation Excreation 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Biotransformations 1212570_28446780.jpg logo_mu_cerne.gif ‹#› Biotransformations