Quiz #4 - The Lithosphere and Its Pollution

GEOSPHERE

• all metals, rocks, minerals, soils, landforms, etc., comprising the solid earth from crust to core
  

• inner core: solid Fe-Ni alloy

• outer core: liquid Fe-Ni

• mantle

• crust

LITHOSPHERE

• rigid outer layer of the geosphere

• all metals, rocks, minerals, soils, landforms, etc. from the upper mantle to the crust

• mostly solid until seismic triggers force magma towards the surface as lava

• magma: hot fluid made up of minerals and elements

• convection currents and tectonic plate shifts cause magma to push up towards the surface

COMPOSITION

• oxygen (O) and silicon (Si) are the dominant elements in the lithosphere
  

• mantle

• thickest, densest, magnesium (Mg) and iron (Fe) rich

• oceanic crust

• thinner,  denser, magnesium (Mg) and iron (Fe) rich

• continental crust

• thicker, less dense, aluminum (Al) and silicon (Si) rich

MINERAL GROUPS

• naturally-occurring, crystalline, inorganic solids with a specific chemical composition and a highly ordered atomic structure

• fundamental building blocks of rocks and are the primary sources of elements used in environmental and industrial processes

• minerals are grouped based on the anionic constituent within their chemical formula

• ore: naturally-occurring solid material from which a metal or mineral can be profitably extracted

MINERAL GROUPS
silicates: SiO₄^4- 

• comprise ~90% of Earth’s crust

• leads to different structures with varying ratios of silicon (Si) to oxygen (O)

• silicates can form a variety of different structures because it coordinates as a tetrahedron

Mining

• strip/open-pit mining
  

Ore Preparation

• crushing → washing → sorting

Processing

• refined for aluminum production
  

Use

• aluminum cans, aircrafts, ceramics, clays, construction

Concern

• land disturbance; high energy use

MINERAL GROUPS
carbonates: CO₃^2-

• lime/concrete

• calcium carbonate (CaCO₃)

• calcium magnesium

• carbonate CaMg(CO₃)₂

• iron ore

• iron (II) carbonate (FeCO₃)

• iron(III) carbonate (Fe₂(CO₃)₃)

Mining

• quarry blasting & cutting

Ore Preparation

• crushed → sorted by size

Processing

• heated for lime/cement; smelt Fe carbonates

Use

• construction; soil buffering; steel production

Concern

• dust; CO₂ release from heating; weathering

MINERAL GROUPS
oxides: O^2–

• iron ore

• iron (III) oxide (Fe₂O₃)

• iron (II,III) oxide (Fe₃O₄)

• aluminum ore

• aluminum (III) oxide (Al₂O₃)
  

• chromium ore

• iron (II) chromite (FeCr₂O₄)

Mining

• large-scale open-pit or underground

Ore Preparation

• crushing → magnetic/gravity separation

Processing

• smelting in furnaces

Use

• steel production

Concern

• tailings, greenhouse gases

MINERAL GROUPS
sulfides: S^2–

• cooper ore

• copper iron sulfide (CuFeS₂)
  

• lead ore

• lead sulfide (PbS)
  

• zinc ore

• zinc iron sulfide (Zn,FeS)

• nickel ore

• iron nickel sulfide ((Fe,Ni)₉S₈)

Mining

• underground/open-pit

Ore Preparation

• crushing → milling → flotation

Processing

• smelting/refining

Use

• Cu wiring/pipes, Pb batteries, Zn galvanizing

Concern

• acid mine drainage, toxic tailings

MINERAL GROUPS
sulfates: SO₄^2–

• hydrous sulfates

• calcium sulfate dihydrate (CaSO₄•2H₂O)

• anhydrous sulfates

• calcium sulfate (CaSO₄)

• barium sulfate (BaSO₄)

Mining

• surface quarrying

Ore Preparation

• ground to powder

Processing

• minimal, as it is often used directly

Use

• cement, plaster, drywall, drilling fluid

Concern

• dust; habitat disturbance

MINERAL GROUPS
halides: F^–, Cl^–, Br ^–, etc.

• sodium chloride (NaCl)

• calcium fluoride (CaF₂)

Mining

• room-and-pillar mining; evaporation ponds

Ore Preparation

• crushed → washed → sorted

Processing

• purified and packaged

Use

• table salt, water softeners, remove impurities in steel-making
  

Concern

• sinkholes; brine waste

MINERAL GROUPS
phosphates: PO₄^3-

• contains many other minerals; therefore, phosphates have plenty of chemical diversity 

• ions of similar size and charge can substitute for one another in the crystal structures
  

• calcium phosphate minerals

• apatite: Ca₅(PO₄)₃(OH,F,Cl)
  

Mining

• strip mining
  

Ore Preparation

• crushing → washing → flotation
  

Processing

• reaction with an acid

Use

• fertilizers, detergents, livestock feed
  

Concern

• eutrophication; radioactive byproducts

MINERAL GROUPS
native elements

metals

• platinum (Pt)

• iridium (Ir)

• osmium (Os)

• iron (Fe)

• zinc (Zn)

• tin (Sn)

• gold (Au)

• silver (Ag)

• copper (Cu)

• mercury (Hg)

• lead (Pb)

• chromium (Cr)

• platinum (Pt)

• iridium (Ir)

• osmium (Os)

• gold (Au)
  

siderophiles

• elements that sink to the core to dissolve in iron (Fe)

semimetals

• bismuth (Bi)

• antimony (Sb)

• arsenic (As)

• tellurium (Te)

• selenium (Se)

nonmetals

• sulfur (S)

• carbon (C) (diamond, graphite, amorphous)

Mining

• placer or hard-rock mining

Ore Preparation

• gravity sorting → crushing → milling

Processing

• smelting, refining, cutting/polishing
  

Use

• jewelry, electronics, lubricants, etc.
  

Concern

• cyanide (CN^-) or mercury (Hg) contamination, sediment disruption, water demand

IMPURITIES IN MINERALS

• color variations in minerals is due to impurities within the chemical composition

• “Impurities such as silicon dioxide (SiO₂), iron oxides (Fe_xO_y), and graphite (C) give marble its color and characteristic rich veining and clouding.” – Britannica

• Rutilated quartz, is made of silicon dioxide (SiO₂), with titanium dioxide (TiO₂).

• The trace presence of calcium (Ca), iron (Fe), zinc (Zn), chromium (Cr), magnesium (Mg), etc. give Himalayan salt its pink, reddish, or beet-red color.

• “All natural diamonds contain some nitrogen (N) impurities. The traditional classification of natural diamonds is based on their nitrogen (N) content.” – Chemical Review, 2020

ROCKS

• naturally-occurring aggregate of different minerals that fused together due to high pressures and temperatures over a long period of time

• rocks are grouped by how they were formed

Igneous

• magma (molten rock) that has either cooled slowly underground or quickly at the surface
  

Sedimentary

• the weathered products of other rocks accumulating at the surface and then buried by other sediments

Metamorphic

• igneous or sedimentary rocks that form new minerals (therefore new rocks) with heat and pressure

THE ROCK CYCLE IN ACTION

• examples:

• limestone is a sedimentary rock

• calcium carbonate (CaCO₃) fossils

• shells, sand, and mud deposited at the bottom of oceans and lakes solidify into rock

• marble is a metamorphic rock

• sedimentary limestone (CaCO₃) undergoes pressure and heat so that the grains recrystallize

• coloration is due to impurities within the chemical composition

ORGANIC MATTER

• percentage of soil that consists of decomposing plant and/or animal tissue

• primarily composed of carbon (C), hydrogen (H), and oxygen (O) with humus being the final product 

• humus: stable organic matter that is resistant to further degradation

• role in soil structure, water retention, and nutrients in the form of nitrogen (N)

NITROGEN CYCLE

• transformations of nitrogen (N) moving through the spheres

  • atmosphere, lithosphere, hydrosphere, and biosphere

• primarily driven by specialized bacteria

• nitrogen fixation converts atmospheric nitrogen (dinitrogen: N₂) into bioavailable forms

• triple bonds are shorter and stronger than double bonds 

• nitrogen (N₂) does not react readily because it is a strongly bonded, stable compound

• REMEMBER THIS IMAGE! Nitrogen cycle = creation of N₂

NITROGEN CYCLE: NITROGEN FIXATION

• atmospheric dinitrogen (N₂) converts to ammonia (NH₃) / ammonium (NH₄⁺)

• N₂ 🡪 NH₃ / NH₄⁺

• enzyme-catalyzed reduction by microorganisms

• microbes with the enzyme nitrogenase can use electrons and protons from the microbial metabolism to convert dinitrogen (N₂) to ammonia (NH₃)

NITROGEN CYCLE: NITRIFICATION

• ammonia (NH₃) / ammonium (NH₄⁺) to nitrite (NO₂^-) and then nitrate (NO₃^-)

• NH₃ / NH₄⁺ 🡪 NO₂^- 🡪 NO₃^-

• enzyme-catalyzed oxidation by microorganisms

NITROGEN CYCLE: ASSIMILATION

• ammonia (NH₃) / ammonium (NH₄⁺) and nitrate (NO₃^-) yielding organic nitrogen compounds (R-NH₂) 

• NH₃ / NH₄⁺ / NO₃^- 🡪 R-NH₂

• assimilated by bacteria, fungi, algae, and plants

• Amino acids: these organic nitrogen (N) compounds found in the environment can move up the food chain to higher organisms

NITROGEN CYCLE: AMMONIFICATION

• conversion of organic nitrogen compounds (R-NH₂) into ammonia (NH₃) /ammonium (NH₄⁺)

• R-NH₂ 🡪 NH₃ / NH₄⁺

• decomposed by fungi and microorganisms

NITROGEN CYCLE: DENITRIFICATION

• removing bioavailable nitrogen (N) and returning it to the atmosphere

• NO₃^- 🡪 NO₂^- 🡪 NO 🡪 N₂O 🡪 N₂

• anaerobic reduction by microorganisms
  

• Denitrifying bacteria:

• nitrate (NO₃^-)

• nitrite (NO₂^-)

• nitric oxide (NO•)

• nitrous oxide (N₂O)

• dinitrogen (N₂) 

SOIL TEXTURE

• determine soil class based on the percentage of clay, silt, and sand

• primarily composed of silicates (SiO₂)

• water retention

• porosity

• nutrient

• resource use

CLAY	< 2µm
SILT	4 – 20 µm
SAND	20 – 2000 µm
fine coarse	20 – 200 µm 200 - 2000 µm

• FOR EXAMPLE:

• 100% SOIL = 35% CLAY + 25 % SAND + 40% SILT

SOIL: COMPOSITION

• rock particles: 45-50%; contains minerals; mostly silicates

• air: oxygen (O₂) for plants and animals; water storage spaces

• water: sustains plant and animal life

• organic matter: nutrients

SOIL: FACTORS

• climate: temperature, rainfall, etc.

• organisms: flora and fauna

• relief: topography and slope stability

• parent material: type of bedrock

• time: how long in place

SOIL: SOIL CHEMISTRY

• Nitrogen Cycle

• Soil Texture Triangle

• Cation Exchange Capacity

CATION EXCHANGE CAPACITY

• capacity of the soil to hold on to cations

• held by negatively charged clay and organic matter particles in the soil via electrostatic forces

• cations are easily exchangeable with other cations

• (drier climate = higher salinity)
  

• calcium (Ca²⁺) - 

• magnesium (Mg²⁺)

• potassium (K⁺)

• 🡪 nutrient cations plants use in the largest amounts

• sodium (Na⁺)

• 🡪 higher [Na⁺] in drier climates
  

• iron (Fe²⁺)

• manganese (Mn²⁺)

• zinc (Zn²⁺)

• copper (Cu²⁺)

• 🡪 micronutrients for plants

• ammonium (NH₄⁺)  

• 🡪 low [NH⁴⁺] due to nitrification

• hydrogen (H⁺)

• aluminum (Al³⁺)

• 🡪 detrimental effects

LITHOSPHERIC POLLUTION

ACID DEPOSITION

• acidifying soils

• erosion, sinkholes, caves, and underground rivers

• leaching toxic metals and nutrients
  

MINING & EXTRACTING

• disturbance of soils and bedrock and habitats

• generation of tailings and mine waste

• acid mine drainage

• hydraulic fracturing
  

DOMESTIC WASTE

• solid municipal waste in landfills

AGRICULTURE

• fertilizers causing nutrient pollution

• pesticides, herbicides, etc. causing chemical pollution

DRY & WET ACID DEPOSITION

DRY DEPOSITION

• acidic gas, dust, or particles, typically from  SO_{x (g)} and NO_{x (g)} species, that deposit directly onto surfaces

• form acids in situ when in contact with surface moisture (dew, water films, wet leaves, etc.)

WET DEPOSITION

• acidic substances dissolved in precipitation (rain, snow, sleet, fog, or hail) that fall to Earth

• gases SO_{x (g)}, NO_{x (g)}, and CO₂ _(g) dissolve in atmospheric water droplets and react to form acids

• SULFUR OXIDES (SO_x)

• SO_{2 (g)}  🡪  SO_{3 (g)}  🡪  H₂SO_{4 (aq)}
  

• NITROGEN OXIDES  (NO_x)

• 2 NO• _(g)  🡪  2 NO_{2 (g)}  🡪  HNO_{3 (aq)}

• CARBON DIOXIDE

• CO_{2 (g)}  🡨🡪  H₂CO_{3 (aq)}

SULFATE (SO₄^2-) DEPOSITION IN THE U.S.

• using National Atmospheric Deposition Program (NADP) and Clean Air Status and Trends Network (CASTNET)

• reduced sulfate (SO₄^2-) deposition is a result of the Clean Air Act (1970) and its amendments (1990) 

NITRATE (NO₃^-) DEPOSITION IN THE U.S.

• using National Atmospheric Deposition Program (NADP) and Clean Air Status and Trends Network (CASTNET)

• “reduced” nitrate (NO₃^-) deposition is a result of the Clean Air Act (1970) and its amendments (1990) 

LITHOSPHERIC DISSOLUTION

• calcium sulfate: CaSO₄

• calcium nitrate: Ca(NO₃)₂

• calcium bicarbonate: Ca(HCO₃)₂

• Calcium carbonate (CaCO₃) reacts with acid deposition (H₂SO₄, HNO₃, or H₂CO₃) causing chemical weathering.

• Calcium bicarbonate (Ca(HCO₃)₂) is moderately soluble, releasing calcium (Ca²⁺) and bicarbonate (HCO₃⁻) ions into soils and waterways where they enhance carbonate weathering and influence the carbon cycle.
  

• CaCO_{3 (s)}  +  H₂SO_{4 (aq)}  🡪  CaSO_{4 (s)}  +  H₂O_(l)  +  CO_{2 (g)}

• CaCO_{3 (s)}  +  2 HNO_{3 (aq)} 🡪 Ca(NO₃)_{2 (aq)} +  H₂O_(l)  +  CO_{2 (g)}

• CaCO_{3 (s)}  +  H₂CO_{3 (aq)} 🡪 Ca(HCO₃)_{2 (aq)}

SINKHOLES, CAVES, & UNDERGROUND RIVERS

• “Map shows karst areas of the continental United States having sinkholes in soluble rocks (carbonates and evaporites), as well as insoluble volcanic rocks that contain sinkholes. The volcanic bedrock areas contain lava tubes that are voids left behind by the subsurface flow of lava, rather than from the dissolution of the bedrock.” – USGS 2020

• carbonate (CO₃^2-)

• evaporite: sulfates (SO₄^2-) and halides (Cl^-)

• volcanic: silicates (SiO₄^4-)

• (Sinkholes are showing that soluble carbonate rocks are dissolving due to dry and wet acids.)

LITHOSPHERIC LEACHING

NUTRIENT LEACHING

• sulfate (SO₄^2-), nitrate (NO₃^-), and carbonate (CO₃^2-) can attach to cations in soil making these cations unavailable, thus potentially removing nutrients

• hydrogen ion (H⁺) can then take the place of these cations, acidifying the soil

TOXIC CATION LEACHING

• hydrogen ion (H⁺) can displace toxic metal cations, acidifying the soil

• toxic metal cations are even more soluble and mobile in acidic environments and will continue leaching into biological systems
  

• The lithosphere is mostly made of silicates.

• Plant roots actively use an acid-driven process called cation exchange to acquire essential nutrients. However, an excess of certain acidic cations, like aluminum, can become toxic and cause plant death, especially in highly acidic soils. 

TOXIC METALS, LEACHING, & ACIDIFICATION

• soil acidification

• nutrient leaching

• toxic metal leaching

• loss of habitats and/or food sources, limiting biodiversity and causing food chain imbalances

• Critical pHs

• Frogs can survive at pHs ~4

• However, their food source (mayflies) will not survive at pH ≤ 5.5

ACID MINE DRAINAGE

• occurs primarily when sulfide (S^2-) minerals in mine tailings, waste rock, or exposed bedrock are oxidized by water (H₂O) and oxygen (O₂)

• release hydrogen ions (H⁺) which lower the pH (~2.5 – 4) and maintain the solubility of the ferric ion (Fe³⁺)

• dissolves heavy metals like copper (Cu) and mercury (Hg) into the groundwater and/or surface water

• if the pH were to increase, ferric ion (Fe³⁺) precipitates as iron(III) hydroxide (Fe(OH)₃)

DON’T have to know these reactions:

• 2 FeS_{2 (s)}(+ 7 O_{2 (g)} + 2 H₂O_(l) 🡪 2 Fe²⁺_(aq) + SO₄^2-_(aq) + H⁺_(aq)

• 4 Fe²⁺_(aq) + O_{2 (g)} + 4 H⁺_(aq) 🡪 4 Fe³⁺_(aq) + 2 H₂O _(l)

• FeS_{2 (s)} + 14 Fe³⁺_(aq) + 8 H₂O _(l) 🡪 15 Fe²⁺_(aq) + 2 SO₄^2-_(aq) + 16 H⁺_(aq) 

• FeS₂: iron disulfide (pyrite)

• Fe²⁺: ferrous ion

• Fe³⁺ : ferric ion

LANDFILLS

• landfill: large hole in the ground that holds solid waste and is covered by soil/clay

• leachate: water that leaches into a landfill and liquid that drains from a landfill

• methane (CH₄) and carbon dioxide (CO₂) are primary gases produced from the decomposition of organic matter

• 2 H₂S + 3 O₂ → 2 SO₂ + 2 H₂O

WET/DRY ACID DEPOSITION

• SO₂ →  SO₃  → H₂SO₄

COMPOSITION OF REFUSE

• refuse: solid waste (typically nonhazardous) that is collected and transported to a disposal site

• cellulose: a long chain of repeating glucose (sugar) molecules

• hemicellulose: made up of a variety of repeating sugars

• lignin: carbon-rich polymer that resists decay; main component of humus which is the final product of organic matter decomposition

• methane (CH₄) and carbon dioxide (CO₂) are primary gases produced from the decomposition of organic matter

FOUR STAGES OF LANDFILL DECOMPOSITION: AEROBIC PHASE

Four stages of decomp NOT on upcoming quiz!!!

• depletion of oxygen (O₂)

• temperature increase

• high carbon dioxide (CO₂) production

• minimal loss of solids

• pH is ~5.5 - 6.5

• (CH₂O)_N + H₂O  → (CH₂O)_n + (CH₂O)_n

• (CH₂O)_n is the empirical formula for most sugars 

• Where… “N” represents a long polysaccharide chain + “n” represents a smaller chain than “N”

• (CH₂O)_n  +  n O₂  →  n CO₂  +  n H₂O  +  heat

• Where… “n” represents a smaller chain than “N” for the long polysaccharide chain shown in previous slides

FOUR STAGES OF LANDFILL DECOMPOSITION: ANAEROBIC ACID PHASE

Four stages of decomp NOT on upcoming quiz!!!

• no oxygen (O₂) infiltration

• organic acids accumulate

• minimal carbon dioxide (CO₂) production

• possible hydrogen (H₂) production

• minimal loss of solids

• pH is ~5.0 – 6.0

• fermentation: microorganisms breaking down sugars to acetic, lactic, and formic acids (-COOH), alcohols (-OH), and gases (CO₂ and H₂)

• products are dependent on many variables

FOUR STAGES OF LANDFILL DECOMPOSITION: ACCELERATED METHANE PHASE

Four stages of decomp NOT on upcoming quiz!!!

• high methane (CH₄) production

• gas composition is 50:50 methane (CH₄)/carbon dioxide (CO₂)

• pH is ~7 - 8

• significant solid decomposition begins

• microorganisms decompose organic acids (-COOH) to methane (CH₄) and carbon dioxide (CO₂)

• 2 CH₃COOH  🡪   CH₄  +  3 CO₂

• acetic acid

• 2 C₃H₆O₃  🡪  3 CH₄  +  3 CO₂

• lactic acid

• HCOOH  🡪  H₂  +  CO₂

• formic acid

FOUR STAGES OF LANDFILL DECOMPOSITION: DECELERATED METHANE PHASE

Four stages of decomp NOT on upcoming quiz!!!

• decrease in methane (CH₄) production

• pH is > 7

• significant solid decomposition but slower rate
  

STABILIZATION

• degradable solids consumed

• oxygen (O₂) infiltrates

• geological timescale

CRUDE OIL & NATURAL GAS WELLS

• drilling: extraction of natural gas and/or crude oil (fossil fuels) from the lithosphere by drilling a hole to reach a reservoir, and then using tubing to pump the oil or gas to the surface

• conventional drilling: vertical well

• unconventional drilling: horizontal wells

• hydraulic fracturing (“fracking”): “crack open rocks deep below the earth’s surface to access trapped fossil fuel deposits” - Natural Resources Defense Council (NRDC)

FRACKING FLUID

• freshwater with proppants, base fluid, and additives

proppants: allows oil or gas to flow

• sand

• ceramic pellets

• small incompressible particles

base fluid: “applies pressure … to the fractures”

• water

• oil

• methanol

• liquid carbon dioxide

• liquified petroleum gas

additives: “maintain the integrity of the oil or gas” and equipment

• biocides: inhibit microorganism growth

• acids: dissolve minerals and debris

• pH adjustors

SEISMIC ACTIVITY

• high pressure injection of wastewater (and hydraulic fracturing fluid) and into naturally-occurring faults, as well as natural or man-made fractures

• Fractures can’t be controlled!

• Fractures can be upwards of…

• ~ 6 mm in width

• ~ 400 m in length

• ~100 m in height

• 1 meter = 3.28 ft

WATER USAGE & CONTAMINATION

• ground and surface water sources are drained

• large volume of wastewater is produced

• fractures cause groundwater and surface water contamination

• gas, oil, hydraulic fracturing fluid, and radionuclides

• radionuclides: “an unstable atom that releases high energy radiation as it breaks down to become more stable” – National Cancer Institute

• naturally-occurring radioactive materials (NORMs), such as uranium (U), thorium (Th), and radium (Ra), that are found in gas and oil deposits and can dissolve in water (H₂O)

SOIL PURIFICATION: BURIAL

• IN SITU: removal of the contaminant(s) while soil is in its original place

• EX SITU: removal of contaminated soil prior to removing the contaminant(s)

Burial & Capping

• migration of pollutants can occur by:

• rainwater moving through the soil

• surface water moving over the ground

• wind blowing across the site

• covers the area with concrete, asphalt, clay or a geomembrane material preventing the migration of pollutants from the contamination site
  

SOIL PURIFICATION: IMMOBILIZE

Solidification & Vitrification

• “… adds a binder to the media … change the physical properties of the media … results in a decrease in its permeability and an increase in its compressive strength."

• Federal Remediation Technologies Roundtable

SOIL PURIFICATION: MOBILIZE

SOIL PURIFICATION: DESTROY

Incineration & Bioremediation

• Phytoremediation = uses plants to remove or contain contaminants

CONTAMINANTS 

• metals

• pesticides

• solvents

• explosives

• crude oil and its derivatives

PLANTS

• mustard plants

• alpine pennycress

• hemp

• pigweed