Lecture Outline 3

1
Lecture Outline 3

• Aqueous Env. Geochemistry
• Dr. K

2
Surface Reactions

• Electrostatic attraction of solute (mainly
  dissolved metals) to mineral grain (mainly to
  humus, clays, and iron oxy-hydroxides).
• Depends on chemical env. (pH/Eh), sorbent, and
  cations in question (ZngtMn)
• Importance and practical applications of sorption
• Sorption Isotherm Partitioning of dissolved
  masses btwn solution and solid surfaces
• S (Ci-C)(Sol. Volume)/Sed. Mass
• S mass sorbed in mg/L Ciinitial conc.
  Cfinal conc. In mg/L
• Freundlichs EqS KCn (done w/ varied conc.of
  a sol.)
• Kpartitioning coeff. (large K more sorption),
  n 0.7-1.2

3
Surface Reactions (contd)

• Sorption of Organic Compounds Like attracts the
  Like
• K KocFoc gtlogK log Koc log Foc
• log Koc 0.490.72 log Kow (i.e. tabulated value
  of Octanol-Water partitioning)
• Foc fraction of organics (LOI)
• Ion Exchange stoichiometric reversible
  chemical reactions between ion in a solution
  (solutes) and another ion with similar properties
  in immobile resin or crystal surfaces.
• Ca Na-clay 2Na Ca-clay
• VermgtMont.gtChlgtIllgtKaol. are - and attracts
  cations
• AlgtCagtMggtNH4gtKgtHgtNa (in order of strength)

4
Metals

• What is a metal? What are some common
  characteristics of metals?
• In what forms do metals occur in water? Give
  examples of those forms.
• Why do we need to know about metals? How do
  metals relate to human health and functionality,
  i.e. what are some health risks associated with
  various trace metals?
• Trace metals in estuaries, bays, and wetlands
• What are some natural and human-induced sources
  of metals? Which of the metals are important for
  drinking and irrigation waters?

5
Metals (contd)

• What biochemical processes and factors are
  important in mobility and metal chemistry?
• pH, Eh, DO, collides, humus, bacteria
• What are some health risks associated with trace
  metals? Know the MCL for imp. Metals in drinking
  water.
• As, Cr, Pb, Zn, Cu, Co, Ni, Cd, etc.
• Methods/procedures in analyzing metals
• AMD? What chemicals reactions and processes are
  involved in AMD affected areas?
• Dont forget the role of Al (from acidic clay and
  hydrolysis) Mn in acidity
• What are some treatment processes used in AMD
  affected areas?
• Active vs. passive treatment and their pros and
  cons
• Understand AMD treatment reactions and AMDTreat
  software to design treatment facilities

6
AMDTreat Software
7
Nutrients

• What is a nutrient? What are some examples of
  nutrients? Why are they important?
• What are some sources, pathways, and sinks of
  nutrients and why do we need to understand them?
• What are some components of the nitrogen and
  phosphorus cycles? What are some sources/sinks
  and forms of nitrogen and phosphorus that are
  parts of the cycle?
• What processes are important in nitrogen cycle?
• What are the forms of nitrogen and phosphorus
  that we analyze in the lab?
• Tot. N Org. (NH3 NH4) Inorg. (NO3NO2)
• Tot. P Org. Inorg. (Condensed meta poly P
  Ortho)

8
Nutrients (contd)

• What relationship exists between landuse and
  nitrogen availability? What about nitrate vs.
  time, nitrate vs. depth, nitrate vs. fertilizer
  used, etc. relationships?
• How can we use the natural (de)nitrification
  principles in treating watste-water using
  microbes? How much methanol is needed as required
  organics to do this?
• How can you better management nitrogen for crops?
  What are some BPMs used for efficient N and P
  use? What are some practical/local issues
  related to nutrient management plan?
• How to delineate the sources of nitrogen
  pollution?

9
Organic Chemicals

• What is an organic chemical? What are some
  characteristics of organic compounds?
• What are the sources of organic chemicals found
  in natural water?
• Org. decay (TOC/TOX), domestic/commercial (1000s
  of VOC/SVOC), Pesticide (SOC), Halogenated/Polychl
  orinated (PCB), disinfection by-prod (DBP)
• What are the common groups or categories of
  organic chemicals in terms of their behavior or
  properties? Know examples of each groups or
  category.
• Alipatic (chain) vs. aromatic (ring)
• What are some uses of organic chemicals. Give
  examples.
• Gasoline, pesticides, deodorant, pharma., septic
  tank, textile, dry cleaning, solvent, degreaser,
  indus. waste treatment, gums, glues, resins,
  MTBE, etc
• How can we get the organic chemicals in our body?
  What are the health risks associated with organic
  chemicals in drinking water?
• Variesfrom being a nuisance to toxic,
  carcenogenic, mutogents
• We can get them thru air, ingestion, water, food
  chain, absorbtion

10
Organics (contd)

• How are VOCs different from each other? Know the
  examples of different types of VOCs.
• Three groups petroleum prod (BTEX LNAPL)
• Halogenated VOCs solvent/degreaser (TCE, DCE
  DNAPL)
• DBP from water treatment THM, HAA, etc.
• Examples of uses health risks of VOC
• Benzene (in gasoline)
• MTBE (additive to gasoline)
• Toluene (solvent for paint, gums, resin)
• Xylene (in gasoline, solvent, pharma.)
• PCE TCE (solvent, degreaser, textile, dry
  cleaning
• DCB (deodorant in indus. wastewater treatment)
• CTC (carbon tetra-chlorine) in fire extinguisher,
  fumigants
• How the DBP form?
• Ammonia (NH3) from chlorination and HCl (from
  chlorine) NCl3 (toxic)
• THM includes chloroform, form during chlorination
• What are the health risks associated with DBP
  (THM HAA)?
• Affects kidney, liver, etc.

11
Biological Radioactive Pollutions

• Know the components of a water treatment facility
  and various chemicals that are used in such
  facility. What parameters are measured in a
  water treatment facility (H/O)?
• What are the most common groups disease-causing
  micro organisms?
• Bacteria salmonella, shigella, E. Coli,
  vibrio-cholerae
• Total coliformgtfecal coliform.E.coli
• Enteric virus polio-, rota-, astrovirus,
  hepatitis
• Protozoa giardia, cryptosporidium, BG-algae
• Fungi

12
Biological/radioactive Pollutions (contd)

• What are some common radioactive pollutions in
  water?
• Radon gas (4 pCi/L in air, 300 pCi/L in H2O)
• Uranium (20 ug/L in H2O)
• How do we prevent radioactive pollutions?

13
Water Resources Management

• What are the most important issues that you need
  to be aware of in geochemical sampling,
  preservation, and measurements both in field and
  lab?
• What are the most common methods/techniques used
  for remediation of contaminated soils and/or
  groundwater?