1. Common Toxic Pollutants and Analytical Methods

2. Characteristics of “Contaminants of Concern”
TOXIC
- Makes you sick.
- Kills you.
- Gives you cancer.
- Endangers plants/animals
PERSISTENT
- Remains in the environment for “a long time”: Months, years.
Breaks down slowly or not at all
BIOACCUMULATIVE
“Builds up” in the tissues of organisms. Accumulates.
- May amplify up a food chain
(e.g., Hg in ocean -> tuna)

3. Toxicity EXPOSURE - Dose + Duration ACUTE Short-term, high dose
CHRONIC
Long-term, low dose
TOXIC ACTION
Example
Somatic failure
Kidney, liver failure, nervous system damage
Carcinogenesis
Cancer
Teratogenesis
Birth defects

4. Classes of Toxic Contaminants
Inorganic materials
Synthetic organic compounds

5. Inorganic Toxic Materials
Metals:
Transition metals on the periodic table
Mode of toxicity: Often substitute for or interrupt function of normal biological metals (e.g., Fe, Ca, Zn)
Main Toxic Metals in ~Order of Toxicity Hg Cd Pb
(Ag) Cu Zn

6. Other Toxic Inorganics
Metalloids
Arsenic (As)
Selenium (Se)
“Transient” compounds (easily break down, rarely persistent)
Ammonia (NH3)
Hydrogen sulfide (H2S)
Cyanide (CN-)

7. Inorganics: Key Characteristics
Cannot degrade or break down
E.g., Pb is Pb is Pb
Hence inherently “persistent”
“Speciation” often important
A metal may occur in various chemical forms or “species”
E.g., different redox states, or bound to various other materials
Different species may have very different properties

8. Examples of Speciation Effects
Metal Species
Toxicity
Mobility
Hg2+
Hg0
Hg(CH3)2
Less toxic
Toxic
Extremely toxic
Low mobility
Volatile gas
~High mobility
Cr3+ (trivalent)
CrO42- (hexavalent)
Low toxicity
High toxicity
High mobility

9. Total Metal vs Species Total metal = “analytical concentration”
More complicated: Individual species may be analyzed
Or, sometimes easier or necessary to calculate species with chemistry tools or computer model

10. AAS: Atomic Absorption Spectrometry

11. Flame AAS

12. Gas Chromatography

14. Gas Chromatography

15. Typical GC

16. GC Autosampler

18. GC

21. GC-Mass Spectrometry GCMS

24. GC (with Mass Spectrometry)

25. GCMS “Fingerprint”