What’s missing? Reactions/degradation Air Water Octanol A gas is a gas is a gas T, P Fresh, salt,...
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Transcript of What’s missing? Reactions/degradation Air Water Octanol A gas is a gas is a gas T, P Fresh, salt,...
W et (rain , snow )D eposition
G as
P artic les/aerosols
D epos ition to te rrestria l su rfaces
D ry pa rtic leD epos ition
A ir/w a te r/snow G as exchange
D irec t depos ition to w a te r/snow
S now m e lt& runo ff
D isso lved phase
P artic le bound
P artic le sedim en ta tion
S ed im en t bu ria l
P hytop lankton -inve rteb ra tes-fo rage fish
Aquatic food w ebs
M arine m am m alsP iscivorous fish
W ate rfow l,sea b irds
Terrestrial food webs
L ichen - ca ribou
P lan ts - ca ttle (m ilk, m ea t)
Stra tosphere - ozone layer dep letion
Troposphere - increased U V solar rad iation
CFC , CO 2 , CH 4 G loba l warm ing
Relatively long atm osphere life tim esCO 2 , CFC , CH 4 , P O Ps, m ercury, C l 4 ,C l5 P CDD /FsS PM 2.5
Relatively short atm ospheric life tim esS O x, NO x, CO , VO C s, HC FCs, h igh M W P CD D/Fs, S PM 10, heavy m eta ls
V O Cs, N O xO zone
reac tions w ithH O rad ica l
S O 2 , NO xA cid ic p rec ip ita tion
H 2O
Anthropogenic Sources
N atu ra l S ources
H um ans
H um ans
123
A quatic -Terres tria l-A tmospheric E c osys tem L inkages to Chemic al Cyc les
S .J . E isenreic h (M odified from D. M uir, 1997)
What’s missing? Reactions/degradation
Air
Water
Octanol
A gas is a gas is a gasT, P
Fresh, salt, ground, poreT, salinity, cosolvents
NOM, biological lipids, other solvents T, chemical composition
Pure Phase(l) or (s)
Ideal behavior
PoL
Csatw
Csato
KH = PoL/Csat
w
KoaKH
Kow = Csato/Csat
w
Kow
Koa = Csato/Po
L
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:
• Henry’s Law constant
• Kow
• Aqueous solubility• Reactivity
These (few) properties will determine the chemical’s ultimate fate
malathion
phenol
atrazine
CCl4 carbon tetrachloride
Tetrachlorobiphenyl (a PCB)
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):
• 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
• 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
H, S, G
Resources available to you:
• Your book: it’s marvelous! (check out the appendixes!)
• However, notation can be difficult
• Online resourceshttp://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
• 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
Why the interest?
Classes of compounds
• BTEX
• PAHs, including methylated PAHs
• Halogenated C1 and C2 compounds
• PCBs
• Chlorinated pesticides
• Brominated flame retardants
• Formed from small ethylene radicals “building blocks” produced when carbon based fuels are burned
• Sources are all types of burning
PAHs
Sources of PAH in New Brunswick
Other20%
Gasoline Motor Vehicles6.7%
Diesel Motor Vehicles5.7%
Natural Gas24%
Uncombusted Petroleum/Evaporative Emissions
18%
Surface-Air Volatilization19%
Oil4.7%
(Gigliotti et al, 2003)
Some PAH structures
anthracene
phenanthrene
fluoranthenenaphthalene
benz(a)anthracene
benzo(a)pyrene [BaP]
• 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 (Ames-TA98+s9)
• methyl PAHs are often more biologically active than PAHs
PAHs
• 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
Polychlorinated biphenyls (PCBs)
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 > pentaPre-dated 9/11 in sedimentsVery little is known about toxicity
sample tetra penta unitsRector St., 9/14 5500 1010 pg/LRector St., 9/20 14 <0.1 pg/LNC Sludge, 9/19 28 4.3 ng/kgNC Sludge, 9/25 14 1.1 ng/kgWTC N 1.4 <0.1 pg/LWTC S 1.6 <0.1 pg/LWTC W 0.26 <0.1 pg/LWTC South St 0.2 <0.1 pg/LWTC GW Bridge <0.1 <0.1 pg/LArthur Kill Sediment, 1998 57 15 ng/kg
PBDEsOffice buildings contain brominated flame retardants in computers, furnishings, and upholstery. Little is known about toxicity and background concentrations of these chemicals.
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1-Mono 2-Di 3-Tri 4-Tetra 5-Penta 6-Hexa 7-Hepta 9-Nona 10-Deca
rela
tiv
e a
bu
nd
an
ce
590,000 ng/L, 9/14/01
220 ng/L, 9/20/01
Rector St. run-off contained high levels of deca-PBDE on 9/14