Slide 1

Chapter 1The Environment and Sustainability Science

Environmental Chemistry, 9th EditionStanley E. ManahanTaylor and Francis/CRC Press2010

For questions, contact:Stanley E. Manahanmanahans@missouri.edu1.1From the Sun to Fossil Fuels and Back AgainEarly 2000s have shown evidence of strain on Earth's support systemsShortages and high prices for fuel and materials in early 2008 Leading to economic collapseEvidence of global warming Glaciers melting Loss of Arctic ice capStress and depletion of Earth's natural capital Agricultural land depleted Water sources limited Wildlife habitat lost22The Brief But Spectacular Era of Fossil Fuels Began with coal in latter 1700s Coal-fired steam engine as a source of power Progressed to petroleum and natural gas Petroleum supplies will become exhausted within decades New supplies of natural gas are being found Natural gas is an ideal fossil fuel for many applications Not all coal can be used because of global warming potentialRelative to the time of human life on Earth, the era of fossil fuels must soon endHow it ends and what replaces it will largely determine the welfare of humankind for centuries to come 3Back to the Sun for Energy, Fuel, and Raw MaterialsDirect use for solar heating and solar voltaic power generationIndirect use for wind, biomass, hydroelectric (solar-powered hydrologic cycle)Photosynthetically-Produced Biomass for Synthetic fuelsFermentation of sugars to ethanolChemical conversion of lipids to synthetic diesel fuelChemical conversion of biomass to CO and H2 followed by chemical synthesis of hydrocarbons and alcoholsSeveral abundant sources of biomassCrop byproducts such as corn stoverDedicated crops such as hybrid poplar or corn stoverHighly productive algae, which may even be grown in brackish water41.2. The Science of SustainabilitySustainability or sustainable development is an economic and industrial system that meets the needs of the present without compromising the ability of future generations to meet their own needs (Bruntland Commission 1987) Maintenance of Earths ability to maintain an acceptable level of human activity and consumption over a sustained period of time.Nobel-level breakthroughs required to achieve sustainability (Chu, 2009)1.Solar energy capture and conversion to electricity to improve several-fold2.Improved electric batteries Capture and store electricity from intermittent renewable sources Practical driving range in electric vehicles3.Improved crops to convert more solar energy to biomass chemical energyNow less than 1% Genetic engineering should improve several-fold

5Environmental ScienceThe science of the complex interactions that occur among the terrestrial, atmospheric, aquatic, living, and anthropological systems that compose Earth and the surroundings that may affect living thingsGreen Science and TechnologyThe practice of sustainable science and technologyGreen ChemistryThe practice of inherently safer and more environmentally friendly chemical scienceGreen EngineeringEngineering practiced in a sustainable and environmentally friendly manner 67

Environmental chemistry has developed as a positive force for a clean environment Revealing problems such as by pollutant analysis Measures to control pollution Foreseeing problems before they develop Appropriate action to forestall environmental problemsSupport of other disciplines such as industrial ecology and green chemistry employed in environmental improvement

Toxicological chemistry relates the chemical nature of substances to their adverse effects on organisms81.4 WATER, AIR, EARTH, LIFE, AND TECHNOLOGYMuch of environmental chemistry deals with the interchange of materials among water, air, earth, and biological systems and the effects of technology thereonSee Figure 1.2 (next slide)Biogeochemical cycles describe the interchange of matter and energy among the various environmental spheres Effects of organisms Effects of humans (technology)

910

Water and the HydrosphereCovers 70% of Earths surface97% in oceansMost remaining fresh water in iceWater plays essential roles in all environmental spheresEssential to lifeTransfers plant nutrients from soil to rootsDissolves minerals and forms deposits in the geosphereTransfer of water and energy in the atmosphereMany industrial uses and transfer of energy (latent heat in steam) in the anthrosphere11Air and the AtmosphereSource of essential gasesOxygen for animals and other organismsCarbon dioxide for plant photosynthesisNitrogen converted to chemically combined form as a plant nutrientOxygen, nitrogen and argon for industrial usesProtective functionsFilters out damaging ultraviolet radiationRegulates Earths surface temperature within a range compatible with lifeAspects of Atmospheric ScienceMovement of air massesHeat balanceChemical properties and reactions12Earth: The GeosphereSolid iron-rich inner core/molten outer core/mantle/crustCrust is Earths thin outer skin (5-40 km thick)Interacts with other spheresProvides life support, food, minerals, fuelsGeology is the science of the geosphereConsiders mineral solidsInteraction with waterInteraction with atmosphereEffects upon and by living organismsEngineering geology considers human interactions with and modifications of the geosphere

13The Biosphere: Living OrganismsBiology is the science of lifeDeals largely with macromolecules synthesized by organismsUltimate environmental concern is interaction with lifeToxic substances in the environment affect organisms including humansEnvironmental biodegradation of toxic substances14Technology and the EnvironmentWays in which humans do and make things with materials and energy How humans construct and operate the anthrosphereProduct of engineering based on scienceChallenge is to integrate technology with considerations of the environment and ecologyProperly applied technology can benefit the environmentPollution control technologyConstructed environmental features such as artificial wetlandsEfficient energy conversion processesRenewable energy resource utilizationProduction of goods with minimum wasteHigh-speed, minimally polluting transportation systems151.5ECOLOGY, ECOTOXICOLOGY, AND THE BIOSPHEREThe biosphere is in a thin layer at the interface of the atmosphere with the geosphere and hydrosphereStrong mutual interactions between organisms and the other environmental spheres Earths oxygen produced by organisms Atmospheric CO2 removed by photosynthesis Biological processes largely determine aquatic chemistry Geospheric rocks weathered by organismsSequestering solar energy and carbon as biomass, represented {CH2O}, by photosynthesis: CO2 + H2O + hn {CH2O} + O2Biodegradation of biomass by organisms: CO2 + H2O + hn {CH2O} + O2 16EcologyDeals with the relationships between living organisms with their physical environment and with each otherEcosystemGroup of organisms interacting to mutual advantage and with their environment Cycles of material in ecosystems An organism lives in its habitat in the environment The role it plays is its nicheA population consists of the numbers of a particular species in a habitat 17EcotoxicologyToxicology refers to the detrimental effects of poisonous chemical species (toxicants) on organismsEcotoxicology refers to the detrimental effects of toxicants on ecosystemsAt several levels ranging from biological effects to effects upon whole populations

181.6. ENERGY AND CYCLES OF ENERGY19Earth receives solar energy at 1,340 watts/meter2 at the top of the atmosphere Enormous amount of incoming energy largely in visible region of the electromagnetic spectrumMust re-radiate this energy to outer space as longer-wavelength infrared radiation Light and Electromagnetic Radiation20Electromagnetic radiation carries energy through space at 3.00 x 108 meters/second (c, speed of light)In order of shortest wavelength (more energetic) to longer wavelength (less energetic): gamma>X-rays>ultraviolet>visible>infraredCharacteristics of wavelength (l, meters), amplitude, and frequency (n, s-1 or Hertz) nl = cEnergy: E = hn where h is Plancks constant

Dual wave/particle nature of electromagnetic radiationEnergy Flow and Photosynthesis in Living SystemsFigure 1.3. Energy conversion and transfer by photosynthesis

21

1.7 HUMAN IMPACT AND POLLUTIONPollutant: Substance in greater than natural concentration that is detrimentalContaminants cause deviations from normal concentration but are not pollutants unless they have adverse effects22

1.8 CHEMICAL FATE AND TRANSPORTInterchanges of contaminants released from the anthrosphere among various segments of the other environmental spheres and illustrations of pathways involved in chemical fate and transport. 23

Fate and transport of contaminants controlled largely byPhysical transport: Movement without reacting or interacting with other phasesReactivity: Including chemical or biochemical reactions or physical interactions with other phases24Three Major Environmental Compartments Considered in Chemical Fate and Transport25

Physical Transport(1) Advection: Movement of masses of fluid that simply carry pollutants with them Vertical advection of air or water is called convection(2)Diffusive transport: Molecular diffusion, the natural tendency of molecules to move from regions of higher to lower concentrations Also called Fickian transport Approximated by turbulent mixing such as in flowing water26Reactivity Chemical reactions Biological uptake Binding to and release from surfacesTwo broad categories of reactivity(1)Chemical reactions(2)Interphase exchange In water, binding of soluble species to suspended particles In air, includes evaporation and condensation of species Includes biological processes

27Illustration of the Mass Balance Relationship for a Pollutant with Respect to a Specified Compartment of the EnvironmentSteady state applies when there is not net change of mass of pollutant within the control volume28

Distribution Among Phases Partitioning between major compartments Partitioning between phases within a compartmentPartitioning between water and a solid depends upon a substances solubility or hydrophilicityPartitioning between water and air depends upon vapor pressureSorptionAdsorption onto material surfaceAbsorption within body of material

291.9 CHEMICAL FATE AND TRANSPORT IN THE ATMOSPHERE, HYDROSPHERE, AND GEOSPHEREPollutants in the Atmosphere Volatile organic compounds transported in atmosphere Partitioning between air and atmospheric particlesPollutants in the Hydrosphere More hydrophilic compounds tend to stay in water30

Soil water partition coefficient, Kd, where Cs and Cw are concentrations on solids and in water, respectively

Partitioning of organics onto solids depends upon organic fraction of solidsPollutants in the GeosphereTransport of contaminants depends upon porosity, nature of geospheric solids, nature of contaminants

1.10 ENVIRONMENTAL MISCHIEF AND TERRORISMChemistry can be used for harmful acts Explosives, corrosives, and otherwise damaging substances Toxic substancesChemistry can be used to combat terrorism Instruments to detect harmful substances Protective materialsSome environmental incidents have resembled terrorist attacks1984 Bhopal, India, release of methyl isocyanate that killed 3,5002003 release of toxic hydrogen sulfide with natural gas that killed over 200 in ChinaMeasures that are good practice of environmental chemistry tend to reduce terrorist threats31Protection Through Green Chemistry and EngineeringGreen chemistry is safe and sustainable chemistry Avoids hazards that can be used to do harm Reduces vulnerability such as interruption of materials supplies Avoids use, generation, or storage of hazardous substances Avoids severe conditions that may pose hazards Carefully monitor conditions for trouble

321.11 ENVIRONMENTAL FORENSICSEnvironmental forensics deals with the legal and medical aspects of pollutionImportant in several areas Health effects Legal liabilities Determining responsibilities for terrorist attacks Assessment of hazardous waste sites Suitability of sites for brownfields restorationImportant aspects regarding environmental incidents Source Timing Extent33