Transcript No Slide Title

Aquatic-Terrestrial-Atmospheric Ecosystem
Linkages to Chemical Cycles
Stratosphere
- ozone layer depletion
Troposphere
CFC, CO 2, CH4
- increased UV solar radiation
Global warming
Relatively long atmosphere life times
CO2, CFC, CH4, POPs, mercury, Cl 4,Cl5 PCDD/Fs
SPM 2.5
Relatively short atmospheric life times
SOx, NOx, CO, VOCs, HCFCs, high MW PCDD/Fs,
SPM 10, heavy metals
H 2O
SO2, NOx
3
2
VOCs, NOx
Ozone
Acidic precipitation
1
Anthropogenic
Sources
reactions with
HO radical
Gas
Natural
Sources
Particles/aerosols
Deposition
to
terrestrial
surfaces
Dry
particle
Deposition
Wet (rain,
snow)Deposition
Air/water/snow
Gas exchange
Direct deposition to
water/snow
Snow melt
& runoff
Terrestrial food webs
Plants - cattle (milk, meat)
Lichen - caribou
Humans
Dissolved phase
Particle bound
Aquatic food webs
Waterfowl,
Phytoplanktonsea birds
invertebratesforage fish
Marine
mammals
Particle
Piscivorous fish
sedimentation
Humans
Sediment burial
S.J. Eisenreich (Modified from D. Muir, 1997)
What’s missing? Reactions/degradation
KH = PoL/Csatw
Kow = Csato/Csatw
Koa = Csato/PoL
Air
A gas is a gas is a gas
T, P
Koa
KH
Octanol
Po L
Water
Fresh, salt, ground, pore
T, salinity, cosolvents
Csat
w
Kow
Pure Phase
(l) or (s)
Ideal behavior
NOM, biological lipids,
other solvents
T, chemical composition
Csato
Goals of this course
• To give you the tools necessary to
evaluate the fate of organic chemicals in
the environment in both a qualitative
and quantitative way
• To develop your “chemical intuition”
Chemical intuition means that by
looking at a chemical’s structure you
can guess something about its:
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Henry’s Law constant
Kow
Aqueous solubility
Reactivity
atrazine
malathion
phenol
These (few) properties
will determine the
chemical’s ultimate fate
Tetrachlorobiphenyl (a PCB)
CCl4 carbon tetrachloride
Estimation Techniques
• These important parameters can be
estimated (with varying degrees of success)
from LFERs or bond-contribution methods
(i.e. from the compound’s structure):
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Henry’s Law constant
Kow
Aqueous solubility
Reactivity
• The wildcard is toxicity—difficult to estimate
simply from a compound’s structure.
The whole world can be seen
as a war between
thermodynamics and kinetics
• In the first part of this course, we will concentrate
on thermodynamics, i.e. equilibrium
– Estimations of Kaw, Kow, solubility, etc, which determine
where a compound will ultimately end up.
• In the second part we will look at kinetics, i.e. the
rate at which a chemical is transferred from one
environmental compartment to another (or the
rate at which it is transformed)
– Air-water exchange, box models
Expect familiarity with:
• Chemical structures, bonding
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•
•
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Saturated, unsaturated, aromatic
Oxidation states
Polarity, hydrogen bonding
Functional groups containing O, S, P, N
Heterocycles
Electronegativity
If these terms aren’t familiar, review Chapter 2.
• Basic thermodynamics
DH, DS, DG
Resources available to you:
• Your book: it’s marvelous! (check out
the appendixes!)
• However, notation can be difficult
• Online resources
http://www.chemfinder.com/
http://webbook.nist.gov/
http://www.syrres.com/what-we-do/free-demos.aspx
http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
www.wikipedia.com
Why the interest?
• There are more than 70,000 synthetic
chemicals that are in daily use:
– solvents
– components of detergents
– dyes and varnishes
– additives in plastics and textiles
– chemicals used for construction
– antifouling agents
– herbicides, insecticides,fungicides
Classes of compounds
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BTEX
PAHs, including methylated PAHs
Halogenated C1 and C2 compounds
PCBs
Chlorinated pesticides
Brominated flame retardants
PAHs
• Formed from small ethylene radicals
“building blocks” produced when carbon
based fuels are burned
• Sources are all types of burning
Sources of PAH in New Brunswick
Uncombusted Petroleum/
Evaporative Emissions
18%
Other
20%
Surface-Air Volatilization
19%
Oil
4.7%
Gasoline Motor Vehicles
6.7%
Diesel Motor Vehicles
5.7%
Natural Gas
24%
(Gigliotti et al, 2003)
Some PAH structures
fluoranthene
naphthalene
anthracene
benz(a)anthracene
phenanthrene
benzo(a)pyrene [BaP]
PAHs
• Naphthalene, phenanthrene and
anthracene are found in the gas
phase
• pyrene and fluoranthene are in both
the gas and particle phase
• BaA and BaP are mostly on the
particles, Why???
PAHs
• Metabolized to epoxides which are
carcinogenic; O PAH
• are indirect acting mutagens in
bacterial mutagenicity tests (AmesTA98+s9)
• methyl PAHs are often more
biologically active than PAHs
Polychlorinated biphenyls (PCBs)
• used as coolants - insulation fluids in
transformers, capacitors , plasticizers,
additives to epoxy paints
• are thermally stable and biologically
stable
• can exist in the gas and particle phases
• Banned in the early 1970’s but still a big
problem
Local PCB impacts
• GE ordered to spent approximately $450
million to dredge portions of the upper
Hudson
• The Federal courts have ordered that a
TMDL for PCBs must be established for the
Delaware River
• EPA Water quality criteria: 44 pg/L
• NY state Water quality criteria: 1 pg/L
• Typical levels in these two rivers:
1,000-10,000 pg/L
What else is out there?
When the World Trade Center was
destroyed USEPA and NYSDEC
investigated its impact on water quality
in New York Harbor
Simon Litten,
NYSDEC
The WTC contained about 1 gallon of PCB in the
transformers. Pyrolysis of this material would form
chlorinated dioxins and furans.
Work performed by the NYSDOH in 1981showed that
pyrolysis of PCB containing transformed fluid also
produces chlorinated biphenylenes.
A modern office building is expected to contain
PBDEs. Pyrolysis of PBDEs is expected to produce
brominated dioxins and furans.
PBDD/Fs released into the environment are expected to
undergo reactions where chlorines replace bromines. There
984 polyhalogenated (Br and Cl) dioxins/furans.
Tetra- and Pentachlorobiphenylenes
Tetra > penta
Pre-dated 9/11 in sediments
Very little is known about toxicity
sample
Rector St., 9/14
Rector St., 9/20
NC Sludge, 9/19
NC Sludge, 9/25
WTC N
WTC S
WTC W
WTC South St
WTC GW Bridge
Arthur Kill Sediment, 1998
tetra
5500
14
28
14
1.4
1.6
0.26
0.2
<0.1
57
penta
1010
<0.1
4.3
1.1
<0.1
<0.1
<0.1
<0.1
<0.1
15
units
pg/L
pg/L
ng/kg
ng/kg
pg/L
pg/L
pg/L
pg/L
pg/L
ng/kg
PBDEs
Office buildings contain brominated
flame retardants in computers,
furnishings, and upholstery. Little is
known about toxicity and background
concentrations of these chemicals.
1
relative abundance
0.9
0.8
0.7
0.6
590,000 ng/L, 9/14/01
220 ng/L, 9/20/01
0.5
0.4
0.3
0.2
0.1
0
1-Mono
2-Di
3-Tri
4-Tetra
5-Penta
6-Hexa
7-Hepta
9-Nona 10-Deca
Rector St. run-off contained high levels of deca-PBDE on 9/14