sign in sign up
<<
Home , Environmental chemistry

1/25/2021

Introduction to Environmental

CHEM 196 Giuseppe Petrucci

Spring 2021

1

Introduction Introduction Environmental Compartments The Atmosphere • Environmental Chemistry deals with the origins, transport, reactions, The Hydrosphere The Lithosphere effects and fates of chemical species in the water, air, terrestrial and living The environments. Natural Cycles in the Environment Hydrologic Oxygen Nitrogen • overlaps different branches of chemistry, Phosphorous Environmental Chemistry Terminology including organic, analytical, physical, biological, photo- and geo-chemistry. Contaminant Receptor Sink Dissolved Oxygen (DO) • Environmental Chemistry involves widely different fields, such as (COD) , life , agricultural sciences, medical sciences, public health, policy Biological Oxygen Demand (BOD) and engineering. Threshold Limit Value (TLV)

2 1/25/2021 Introduction CHEM 196 Petrucci 2

1 1/25/2021

Environmental Compartments

3

Introduction Environmental Compartments The environment consists of various compartments, including The Atmosphere The Hydrosphere The Lithosphere The Biosphere Natural Cycles in the Environment Hydrologic • Oxygen Atmosphere Nitrogen Phosphorous • Hydrosphere Terminology Pollutant • Lithosphere Contaminant Receptor Sink • Biosphere Dissolved Oxygen (DO) Chemical Oxygen Demand (COD) Biological Oxygen Demand (BOD) Threshold Limit Value (TLV)

4 1/25/2021 Environmental Compartments CHEM 196 Petrucci 4

2 1/25/2021

Introduction The Atmosphere Environmental Compartments • Protective blanket of gas surrounding the earth (0 – 50 km) The Atmosphere The Hydrosphere The Lithosphere • Absorbs infrared (IR) radiation emitted by the sun and re-emitted from the The Biosphere earth Natural Cycles in the Environment • Controls temperature of the earth Hydrologic Oxygen • Nitrogen Allows transmission of significant amounts of radiation from near UV (300 nm) Phosphorous to near IR (2500 nm) Terminology Pollutant • Blocks transmission of damaging UV radiation (<300 nm) Contaminant Receptor Sink • Source of CO2 for plant photosynthesis and O2 for respiration Dissolved Oxygen (DO) Chemical Oxygen • Source of nitrogen (N2) for nitrogen fixing bacteria and ammonia producing Demand (COD) Biological Oxygen plants Demand (BOD) Threshold Limit Value (TLV) • Transports water from ocean to land

5 1/25/2021 Environmental Compartments CHEM 196 Petrucci 5

Introduction The Hydrosphere Environmental Compartments • Collective term for all different forms of The Atmosphere The Hydrosphere water, including oceans, seas, rivers, lakes, The Lithosphere The Biosphere streams, reservoirs, glaciers, and ground Natural Cycles in waters. the Environment Hydrologic Oxygen • Only ~1% of global water supply is fresh Nitrogen water! Phosphorous Terminology • Primary uses of available fresh water include Pollutant Contaminant Receptor Domestic uses, 7% Sink Industrial water uses, Dissolved Oxygen (DO) 13% Chemical Oxygen Thermal power Demand (COD) plants, 50% Biological Oxygen Irrigation, 30% Demand (BOD) Threshold Limit Value (TLV)

6 1/25/2021 Environmental Compartments CHEM 196 Petrucci 6

3 1/25/2021

Introduction The Lithosphere Environmental Compartments The Atmosphere The Hydrosphere • The Lithosphere Consists of Earth’s crust and upper mantle The Biosphere • Natural Cycles in The crust is the Earth’s outer skin that is the Environment accessible to humans Hydrologic Oxygen Nitrogen • The crust consists of rocks and (most Phosphorous important part to humans and the Terminology Pollutant environment) Contaminant Receptor Sink Dissolved Oxygen (DO) Chemical Oxygen Demand (COD) Biological Oxygen Demand (BOD) Threshold Limit Value (TLV)

7 1/25/2021 Environmental Compartments CHEM 196 Petrucci 7

Introduction The Biosphere Environmental Compartments • Refers to the realm of living organisms and their interactions with the The Atmosphere The Hydrosphere environment (i.e., other compartments). The Lithosphere The Biosphere • Large and complex. Natural Cycles in the Environment Hydrologic • Divided into smaller units called . Oxygen Nitrogen • An constitutes plants, animals and microorganisms that live in a Phosphorous defined zone along with physical factors such as soil, water and air. Terminology Pollutant • Contaminant Each ecosystem contains dynamic interrelationships between living forms and Receptor their physical environment Sink Dissolved Oxygen (DO) • These interrelations manifest as natural cycles, such as hydrologic, oxygen, Chemical Oxygen Demand (COD) nitrogen, phosphorous and sulfur. Biological Oxygen Demand (BOD) • The natural cycles operate in a balanced manner providing a continuous Threshold Limit Value (TLV) circulation of essential constituents

8 1/25/2021 Environmental Compartments CHEM 196 Petrucci 8

4 1/25/2021

Natural Cycles in the Environment

9

Introduction Environmental Compartments Within the environment, natural cycles serve to continuously circulate The Atmosphere The Hydrosphere constituents essential to life and other processes on earth. The Lithosphere The Biosphere Natural Cycles in the Environment Hydrologic Oxygen Nitrogen • Hydrologic cycle Phosphorous Terminology • Pollutant Contaminant Receptor • Sink Dissolved Oxygen (DO) • Phosphorous cycle Chemical Oxygen Demand (COD) Biological Oxygen • Demand (BOD) Threshold Limit Value (TLV) •

10 1/25/2021 Environmental Compartments CHEM 196 Petrucci 10

5 1/25/2021

Introduction Hydrologic Environmental Compartments • Arguably the most important natural cycle. The Atmosphere The Hydrosphere The Lithosphere • Continuous exchange of water between The Biosphere environmental compartments. Natural Cycles in the Environment Hydrologic • 10% of evaporative losses from oceans Oxygen precipitate on land (groundwater). Nitrogen Phosphorous • Groundwater percolates by capillary action to Terminology Pollutant surface soil. Contaminant Receptor Sink Dissolved Oxygen (DO) Chemical Oxygen Demand (COD) Biological Oxygen Demand (BOD) Threshold Limit Value (TLV)

11 1/25/2021 Natural Cycles – Hydrologic 11

Introduction Oxygen Environmental Compartments • Ok, this one is important too... The Atmosphere The Hydrosphere • Important to , The Lithosphere The Biosphere geochemical transformation and life Natural Cycles in processes. the Environment Hydrologic • Energy Oxygen Nitrogen 퐶퐻4 + 2푂2 → 퐶푂2 + 2퐻2푂 Phosphorous • Degradation of organic material Terminology Pollutant 퐶퐻2푂 + 푂2 → 퐶푂2 + 퐻2푂 Contaminant • Weathering of minerals Receptor Sink 4퐹푒푂 + 푂2 → 2퐹푒푂3 Dissolved Oxygen (DO) • Photosynthesis Chemical Oxygen hν Demand (COD) 퐶푂2 + 퐻2푂 퐶퐻2푂 + 푂2 Biological Oxygen Demand (BOD) • Sun screen…(O ) Threshold Limit 3 Value (TLV) ′푂′ + 푂2 → 푂3

12 1/25/2021 Natural Cycles – Oxygen 12

6 1/25/2021

Introduction Nitrogen Environmental Compartments • Incorporation of atmospheric N2 into living The Atmosphere The Hydrosphere matter and chemically bound N in soil, water, The Lithosphere The Biosphere then back to atmosphere Natural Cycles in • Fixation by bacteria and algae the Environment + + Hydrologic 2푁2 + 3퐶퐻2푂 + 3퐻2푂 + 4퐻 → 3퐶푂2 + 4푁퐻4 Oxygen Nitrogen • Nitrification by nitrosomas and nitrobacter Phosphorous + − + Terminology 2푂2 + 3푁퐻4 → 푁푂3 + 2퐻 + 퐻2푂 Pollutant Contaminant Receptor • reduction by microbial action Sink − − Dissolved Oxygen 2푁푂3 + 퐶퐻2푂 → 2푁푂2 + 퐻2푂 + 퐶푂2 (DO) Chemical Oxygen − + + Demand (COD) 2푁푂2 + 3 퐶퐻2푂 + 4퐻 → 2푁퐻4 + 퐻2푂 + 3퐶푂2 Biological Oxygen Demand (BOD) Threshold Limit Value (TLV)

13 1/25/2021 Natural Cycles – Nitrogen 13

Introduction Environmental Compartments The Atmosphere The Hydrosphere The Lithosphere The Biosphere • Denitrification returns N to the atmosphere Natural Cycles in the Environment − + Hydrologic 2푁푂3 + 5 퐶퐻2푂 + 4퐻 → 2푁2 + 7퐻2푂 + 5퐶푂2 Oxygen Nitrogen Phosphorous Terminology • Perturbed by anthropogenic activity. Pollutant Contaminant combustion Receptor 푁2 + 푂2 + ⋯ 푁푂푥 + ⋯ Sink Dissolved Oxygen (DO) Chemical Oxygen Demand (COD) Biological Oxygen Demand (BOD) Threshold Limit Value (TLV)

14 1/25/2021 Natural Cycles – Nitrogen 14

7 1/25/2021

Introduction Phosphorous Environmental Compartments • Central to many processes, including The Atmosphere • Growth/maintenance of animal bones and teeth The Hydrosphere • Cell division involving production of DNA and RNA The Lithosphere The Biosphere • Sources include Natural Cycles in - - • Inorganic phosphorous, such as soluble H2PO4 , HPO4 the Environment and insoluble Ca (OH)(PO ) and Fe (PO ) •8H O Hydrologic 5 4 3 3 4 2 2 Oxygen • Organic phosphorous mainly from conversion of Nitrogen inorganic phosphates and Phosphorous • Terrestrial plants convert inorganic phosphate Terminology Pollutant salts organic phosphate Contaminant Receptor • Animals obtain phosphate by eating plants Sink Dissolved Oxygen • Upon death, is returned to soil (DO) Chemical Oxygen • Soil microorganisms convert returned phosphate Demand (COD) Biological Oxygen into soluble inorganic phosphate (mineralization) Demand (BOD) Threshold Limit • In water, P solubility is controlled by availability of Value (TLV) Fe and Al (under acidic conditions) and Ca (under basic conditions)

15 1/25/2021 Natural Cycles – Phosphorous 15

Introduction Environmental Compartments • Atmospheric oxidation produces higher charge The Atmosphere states The Hydrosphere The Lithosphere • In hydrosphere and soil, S is present in many The Biosphere inorganic and organic forms with oxidation states Natural Cycles in from -2 to +6 the Environment Hydrologic • Most common forms of S include Oxygen • Sulfate (SO 2-), produced via a variety of pathways (e.g., Nitrogen 4 Phosphorous bacterial) + 2− Terminology 2퐻2푆 + 4푂2 → 4퐻 + 2푆푂4 Pollutant 2- Contaminant • Sulfide (S ), produced by reduction of sulfate in organic Receptor rich reducing aqueous environments Sink Dissolved Oxygen 2− + (DO) 푆푂4 + 2 퐶퐻2푂 + 퐻 → 퐻2푆 + 2퐻2푂 + 2퐶푂2 Chemical Oxygen Demand (COD) • Biological Oxygen Sources include Demand (BOD) - - • Inorganic phosphorous, such as soluble H2PO4 , HPO4 Threshold Limit Value (TLV) and insoluble Ca5(OH)(PO4)3 and Fe3(PO4)2•8H2O • Organic phosphorous mainly from conversion of inorganic phosphates and pesticides

16 1/25/2021 Natural Cycles – Sulfur 16

8 1/25/2021

Terminology

17

Introduction Pollutant Environmental Compartments • A substance whose concentration has increased due to human activity, The Atmosphere The Hydrosphere ultimately having detrimental effects on the environment The Lithosphere • Examples include sulfur dioxide (SO2), carbon dioxide (CO2), ozone (O3), Pb, Hg, excess heat, The Biosphere light and sound. Natural Cycles in the Environment Hydrologic Oxygen Nitrogen Contaminant Phosphorous Terminology • A substance that does not occur in , but is introduced into the environment Pollutant through human activity. Contaminant Receptor • A contaminant is called a pollutant when it exerts detrimental effects on human Sink health Dissolved Oxygen (DO) Chemical Oxygen Demand (COD) Biological Oxygen Receptor Demand (BOD) Threshold Limit Value (TLV) • Anything that is affected by the pollutant • Examples include bodies of water, humans, trees, animals and fish

18 1/25/2021 Terminology CHEM 196 Petrucci 18

9 1/25/2021

Introduction Sink Environmental Compartments • The medium that interacts and retains or converts them chemically The Atmosphere The Hydrosphere The Lithosphere The Biosphere Dissolved Oxygen (DO) Natural Cycles in the Environment Hydrologic • Oxygen dissolved in water Oxygen Nitrogen • Vital for aquatic life Phosphorous • Optimum levels in good quality water are 4 – 8 mg L-1 Terminology -1 Pollutant • Water with levels < 4 mg L is considered polluted and unfit for human or animal consumption Contaminant Receptor Sink Dissolved Oxygen (DO) Chemical Oxygen Demand (COD) Chemical Oxygen Demand (COD) Biological Oxygen Demand (BOD) • An index of the organic content of water Threshold Limit Value (TLV) • Most common sink of DO is oxidation of dissolved organic matter (DOM)

• COD of a water sample is determined by chemical oxidation of the DOM by K2Cr2O7 in 50% H2SO4 • Other oxidizable species also react with dichromate, so typically gives erroneously high measurements of DOM

19 1/25/2021 Terminology CHEM 196 Petrucci 19

Introduction Biological Oxygen Demand (BOD) Environmental Compartments • Indicates the capacity of the DOM in a sample of water to consume oxygen The Atmosphere The Hydrosphere • Determined experimentally by measuring DO at beginning and end of a 5-day period in a sealed The Lithosphere sample The Biosphere • Gives the measure of oxygen utilized as a result of oxidation of DOM present in the water sample Natural Cycles in the Environment Hydrologic Oxygen Nitrogen Phosphorous Threshold Limit Value (TLV) Terminology Pollutant Contaminant Receptor • Indicates the permissible level of a toxic pollutant in the atmosphere to which a Sink Dissolved Oxygen healthy individual can be exposed during an 8-hour day without adverse effects (DO) Chemical Oxygen • TLV is found by experimentation on animals, medical knowledge and Demand (COD) Biological Oxygen Demand (BOD) Threshold Limit Value (TLV)

20 1/25/2021 Terminology CHEM 196 Petrucci 20

10