Organics Flashcards
What is different about Organic chemicals and metals?
- Non-radioactive metals
- Trace Metals
- Synthetic organic compounds
Non-radioactive metal traits
Can be transformed but not broken down to “inert substances” (not reactive)
Metabolic products of org. chemicals
- Mostly transformed to benign products
2. Rarely, more bio reactive and potentially toxic than parent compounds
Organic compounds
- Some are essential (AA, lipids, vitamins)
- Many metals have dissolved in seawater that are essential for some organisms
- Many are liphophilic
- End up in fatty tissue
Trace metals
Trace metals in ocean do not volatize from the ocean
- important process leading to transportation of POPs
- Exception- Hg and some metalloids
- high assimilation that gets built up food chain
What makes org contaminants marine pollutants?
- High bioaccumulation potential
- Low aqueous solubility (water dissolving)
- Small enough to pass membranes - High specificty or active sits of enzymes/receptors at membranes
POP’s are not drinking water pollutants
- Limited solubility
- water minor introduction - Absorb to soils, reducing concentration
- Want to stick to solids
- High Kd values
Biomagnification
- Increase in conc. of contaminant as you move up the food wed
- To biomagnify… org chemicals have to be hydrophobic and stable to transformations
- Chemical contaminant levels increase with age - Low excretion rates
Components of crude oil
Paraffins (alkanes) (least soluble)
Naphthenes (Cycloalkenes)
Mono-aromatic compounds and 2-ring naphthalene
Cyclic, often aromatic aromatic compounds that possess elements other than C and H are referred to as hetrocylci compounds
Halogens (I, Br, Cl, Fl)
Important in affecting likelihood org chemicals to be marine pollutants
Bonds are harder to break
Make more hydrophobic
Freons (Fluorines)
- C-Cl bond only broken in stratosphere
- Stable in the ocean
- Serves as oceanic water mass transport tracers
Modern pesticides
have H bonds with O,N,S
- Hydrogen bonding with water
- More soluble
- Less volatilization from water
- More persistent
Pyrethoids
-More hydrophobic
-More likely to accumulate in solid/sediment
Type 1— easily degradable
Type 2— Stable in env.
*Chrysanthemum
Brominated
Flame retardant
Persistent Organic Pollutants
- Stable molecules (persist for long)
- Transport via wind (long range)
- Can accumulate in organisms (biomag.)
- Pose risk to human health and env.
Stockholm Convention
Over 90 countries promise to reduce POP use
-info made to public, education, research, monitoring
Dirty dozen
Aldrin, Chlordane, DDT, Dieldrin, Endrin, Heptachlor,
Hexachlorobenzene, Mirex, Toxaphene, PCBs,Chlorinated dioxins and furans
**Polychlorinated hydrocarbons
-Stable
-Do not degrade to less toxic forms
-Low solubility in water
-Soluble in fats and lipid membranes
Octanol-water partition coefficient (Kow)
-Ratio of con. of chemical in octanol divided by conc in water
High Kow= higher bioaccumulation
Indicate how hydrophobic
*** Provide indication of tendency to accumulate in tissues
Fukushima
20k people died from explosion but none from radiation
Released 100 mill radioactivity
-Iodine
-Cesium (also naturally abundance in seawater)
Sampling radioactivity of fukushima
Used Zooplankton and anthropogenic radioisotopes