725
Tues. Envr and Thurs- 3 credit hours 11 am to 12:15 pm
snow days call me at 942 4880 or cell 919 614 4730
room 0015 MHRC
http://www.unc.edu/courses/2007spring/envr/725/ 001/Envr725.html
Rich Kamens; 966 5452 [e-mail] http://airsite.unc.edu/~kamens/ 1
Introduction to Environmental Physical Organic Chemistry
Environmental chemistry may be defined as "the study of sources, reactions, transport, effects, and fates of chemical species in water, soil, and air environments, and the effects of technology thereon. Manahan, 1994
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Class objectives:
Highlight some important areas in environmental chemistry present some of the common techniques that environmental chemists use to quantify process that occur in the environment It is assumed that everyone has courses in organic and physical chemistry.
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Class objectives:
Partitioning is a thread that runs through the course Linear free energy relationships will be used to help quantify equilibrium and kinetic processes
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Thermodynamics
ui = uo1 +RT ln pi/p*iL fi = i Xipi*pure liquid
RT ln fi hx /fiopure liq = RT lnfi H2O /fiopure liq
fi hx = fi H2O
ln Kp = a 1/T+b
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Vapor pressure
Tb Tb ln p *iL =19(1 ) +8.5(ln )] T T
How to calculate boiling points
* ln piL = ln p* is
(S fus) (Tm Tamb) + R Tamb
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Vapor pressure and Henrys law
K
sat
iaw
P isat = C sat iw
=
sat
iw
* P iL V iw
Solubility and activity coefficients
Octanol-water partitioning coefficients 7
Additional Principles
Organic Acid-bases and LFERs diffusion chemical spills and mass transfer Organic reactions in the environment Solid- liquid interactions photochemistry
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Homework, quizzes, exams
To insure that most of us stay reasonably current with the lectures and readings, an option is to have 6-8 unannounced quizzes throughout the semester. They will take ~10 minutes. The first quiz will be on Chapter 2 since we will not cover Chapter 2. Quizzes will count 10% of your grade.
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Another option is a set of short questions to be answered and handed in before most lectures (5% of grade)your choice!
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There will be a homework problem set associated with each assigned chapter of the book. It is due a week after the completion of the book chapter. These problem sets should take between 3
and 10 hrs.
Answers will graded and returned to you as soon as possible. These will count for 25% of your grade.
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In addition, you are expected to work through the illustrative examples and problems which have answers in the test on your own. Some of these could appear on exams There will be three exams (70% of your grade ), 25% homeworks, 5%???
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Important Environmental Issues
Global warming and stratospheric ozone depletion Concentration of environmental pollutants at the poles; pesticides in foods, etc. Buildup of environmental chemicals in the oceans; contamination of soil and ground water Particle exposure, photochemical oxidant exposure, acid deposition Energy shortages
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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
Some examples of environmental chemicals
Polynuclear Aromatic HC (PAHs) Dioxins Ketones PCBs CFCs DDT O3, NO2, aerosols, SO2
PAHs
Formed from small ethylene radicals building blocks produced when carbon based fuels are burned Sources are all types of burning in ChiangMai, Thailand: a) 2-stroke motorcycle engines b) cars- light diesels c) open burning d) barbecued meat??
Combustion Formation of PAH
Badger and Spotswood 1960
C C C (I) C C C (II)
C
C C (IV) C C C
(III)
Benzo a Pyrene
(VII)
(VI)
(V)
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Some PAH structures
fluoranthene naphthalene
anthracene
benz(a)anthracene
phenanthrene benzo(a)pyrene [BaP] 18
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
Carcinogenic tests with PAHs
Professor Gernot Grimmer extracted different types of smoke particles
He then took the extract and applied it to mouse skin and implanted it into rat lungs How did he obtain extracts? How did he fractionate his extracts??
Extraction by soxhlet extraction starts with solvent (MeCl2) in a flask
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Hot solvent fills this chamber and bathes the filter
Heat
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The solvent in the filter chamber then drains back into the heated flask with chemicals from the particles on the filter
Heat
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The organic liquid in the soxhlet flask can be concentrated by evaporation by a dry nitrogen stream or rotary evaporation the extract can then be fractionated into different polarity compound groups
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Professor Grimmer fractionated the exhaust extracts
Total
HPLC
uv or fluorescence detector
Total PAH 2 PAHs> Total &3 rings 3 rings -PAHs 26
What did Grimmer see when exposed rats and mice to the different fractions?
skin painted mice implanted rat lungs
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40 30 20 10 0
% cancers
Total
PAHs 2&3 rings Total-PAHs PAHs > 3 rings
rat lungs
Mouse-skin
Analysis of reaction products
soxhlet extraction for 3 hours blow up with dry gentle flow of nitrogen to about 0.5 to 1 ml evaporation to about 0.5 to 1 ml 1 to 2 ul injected directly to GC-MS (EI and CI) The remainder solution: derivatization
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In environmental samples why dont we see some large highly oxygenated compounds that form in the atmophere??
Reverse reactions to the original aldehyde parent structures can occur during sample work up/solvent extraction procedures;
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PFBHA O-(2,3,4,5,6-pentafluorobenzyl)
-hydroxylamine for carbonyl groups
acetone or ketone
F
O
PFBHA
F
C R1 R2
F
CH2 O F F
NH2
F R1 C R2 F N O CH2
F
F
H2O
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F
Pentafluorobenzyl bromide (PFBBr)
derivatization for carboxylic and hydroxyl groups
PFBBr
O H3C CH3
F
O
F
HO
C
CH2
C
OH
F
CH2 Br
F F
O
F
F
H3 C
CH3
O CH2 F
HO
C
CH2 C O
HBr
F
F
F
F
F
F
O CH3
CH2
CH3
O CH2 F
F
O C
CH2 C O
2 HBr
F
F
F
F
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BSTFA for carbonyl, hydroxyl, and/or carboxylic
carboxylic acid or alcohol
R OH (CH3 )3 Si O
BSTFA
CF3 C N Si(CH3 )3
H2 N C (CH3 )3 Si O R F3 C O
+
CF3 C O NH Si(CH3 )3
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GC-EIMS for Oxygenated Terpenoids
Compound Mw, g mol-1 -Pinene oxide Mw=152 Structure
O
-Pinene oxide Mw=152
O
m /z (EI) Compound Mw, g mol-1 67 (100) Nopinone Mw=138 109 83 152 79 (100) Menthone Mw=154 71 41 152 67 (100) 94 108 79 137 93 79 136 Camphore Mw=152
Structure
m /z (EI) 83 (100) 55 95 109 83 (100) 56 112 140 95(100) 81 109 55 152 79 (100) 91 108 152
O
O C
Limonene-2-oxide Mw=152
O
H
O
Myrtenol Mw=152
CO H
d-Limonene Mw=136
2-Hydroxy-3pinanone Mw=168
OH O
71 (100) cis -Verbenol 99 168 Mw=152
Cineole Mw=154
O
Myrtenal Mw=150
CHO
84 (100) 71 108 154 139 79 (100) 107 135 150
trans -Pinane-1,10diol Mw=170
HO
trans -p-Menth-6-en2,8-diol Mw=170
C
94 (100) 109 OH 81 137 OH 82 (100) 67 55 70 152 109 OH (100) 59 OH 79
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Thermal desorption particle beam
mass spectrometry (Paul Ziemann)
Particle generator or smog chamber
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Chlorinated dibenzo dioxins and Furans
These are some of the most toxic organics in the environment - LD50 Created by burning organics which have chlorine; incineration is a big source of atmospheric dioxins and furans bleaching in making paper is another source
Combustion Formation of Dioxins from Polychlorinated phenol
OH OH .
Clx
.O
Clx Polychlorinated Phenol
Flame OH
+
C ly
O
+ OH
O
Clx
OH
Cly
Clx
O
Cly 37
Chlorinated dibenzo dioxin
Shaub & Tsang, ES&T 1983.
They have the following general structures
O Cly O
Clx
chlorinated dioxin
They have the following general structures
O Cly O
O Cly
Clx
chlorinated dioxin
Clx
chlorinated furan
More than 200 different structures are possible
Cl Cl O O Cl Cl
The most toxic is either the 2,3,7,8 tetrachlorodibeno dioxin or furan
These types of compounds produce toxic enzymes: arylhydrocarbon hydroxylase and 7-ethoxyresorufin deethylase
At low concentrations they may behave as environmental estrogens
Environmentally, they are unreactive and can be transported long distances They did not start to show up in the environment until the 1920s when there was a big increase in the production of chloro-organics (Professor Ron Hites, and students)
Environmental Fate of Chlorinated Dioxins and Furans
(Czuczwa and Hites, 1984)
Collected core sediment samples from southern Lake Huron in the USA Based on sedimentation rates they established age vs. concentration profiles for chlorinated dioxins and furans
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US coal consumption vs chlorinated aromatic production
700 800
US coal in 10^6 short-tons
500 400
600
Coal
400
300 200 100 0 1860 0 1980
chloroaromatics
200
1880
1900
1920
1940
1960
Year
10^6 lbs Cl-aromatics
600
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Chlorinated aromatic production vs dioxin and furan conc. in lake core samples
1200
Total dioxins and furans in ppt
800
600 800 600 400 200 0 1900 0 1980
chloroaromatics
400
chlorinated dioxins and furans
200
1920
1940
1960
Year
10^6 lbs Cl-aromatics
1000
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PCBs in the U.S. Great Lakes
PCBs were banned in the early 1970s In 1980 Eisenreich and co-workers estimated that still 85% of the PCBs in the US great lakes came from atmospheric sources.
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Polychlorinated biphenyls (PCBs)
Total Flux = Jair + Jrain + Jparticles Jair = vw ( Cw-P/KH) if resistance to mass transfer is in the water phase Jair = va (Cw KH - P)/RT if resistance is in the gas phase
In the late 1980s a fugacity model was used to represent the distribution of PCBs in different environmental compartments
RT ln fair /fiopure liquid = RT lnf H2O /fiopure
liquid
fair = f H2O
In 1990 Eisenreich and co-workers reported that ambient measurements over the great lakes were generally constant for the past 10 years. For the past 15 years sources to the lakes had declined because of the PCB ban. Based on mass transfer calculations it was proposed that during the summer months the lakes were actually a source of atmospheric PCBs. 49
Polychlorinated biphenyls (PCBs)
used as coolants - insulation fluids in transformers, capacitors , plastercisers, additives to epoxy paints are thermally stable and biologically stable can exist in the gas and particle phases
PCB structures
Cl x Cl y
Environmentally, they to used be considered unreactive, but there is evidence for some bio-degradation; they can be transported long distances 51
Up until the 1970s there was a lot of dumping of industrial wastes in the USA In one example, from 1950 to 1975 there were two capacitor manufacturing plants on the Hudson river in New York State, which discharged into the river.
Levels in the river sediments downstream from the plants exhibited concentrations of 10 ppm which was a factor of two higher than commonly found. Dredging was considered financially impossible it was also believed that is very difficult to bio-degrade PCBs with multiple chlorine atoms
Investigations in the 1980s revealed that PCBs in sediments were being slowly converted to the mono and dichloro forms via very slow anaerobic processes. {CH2O} + H2O + 2Cl-PCB---> CO2 +2H++ 2Cl-- +2H-PCB
What do we do now, when new compounds are introduced into the environment...??
toxicity?? low concentration health effects? damage to the ecosystem ? where will it show up in the environment? how is it transported in the environment and what is its lifetime?
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An example is a new compound called D5. It is a silicon-oxygen compound
It is used to make silicone plastics. It is possible that it could be used to replace toxic solvents like toluene and dichloro-methane. Before it can be put into use in the US, we need to know its toxicity, chemical reactivity , environmental half-life, etc.
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New compounds are introduced into the environment ... Toxicity? Where will it go?
H3C Si O Si H3C
CH H3C 3 Si O Si O CH 3
CH 3
H3C Si
CH H3C 3 Si O Si O CH 3
OH
O CH 3 Si
OH.
H3C CH 3
O Si O CH H3C 3
O CH 3 Si CH 3
O CH H3C 3
D5
D4TOH D4D'OH 57
Some examples of environmental exposures
In 1976 there was a significant industrial explosion in the town of Seveso, Italy that spewed out chlorinated dioxins. 735 people were evacuated from the immediate vicinity. Now excess cancers are showing up.
Seveso, Italy Dioxin release
Over the past eight years the birth ratio has changed from 106 males: 100 females to 26:48 observed increases in cancers decline in number of males born
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A similar observation has been made in the bird population
In the Great Lake region of the USA during the 1980s, hatchlings of crested cormorants with a crossed bill deformity were almost always female Male birds did not show the deformity Scientist speculate that the chemicals causing the deformity were also killing the males before they hatched. 60
1. There is a general concern that if we observe abnormalities in wildlife, similar kinds of mechanisms may exist in humans.
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Mercury poisoning off the coast of Minamata, Japan is an example
Fishermen in the 1950s noticed sea birds were dying and feral cats that scavenged fish from the docks were stiff legged Cerebral palsy and mental retardation started showing up in children.
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2. Toxic loads
Scientists have hypothesized that the fetus is sharing the mothers toxic load, and may actually provide some protection to the mother by reducing her internal exposure.
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2. Toxic loads
Children get 12% of their lifetime exposure to dioxins during the 1st year. Their exposure is 50 times greater than an adult during a very critical developmental period.
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2. Toxic loads
Firstborns from dolphins off the coast of Florida usually die before they separate from their mothers
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2. Toxic loads
It is speculated that mother dolphins unload 80% of their accumulated pollutants into their calves, probably during nursing. The greatest exposures occurs with the 1st born Does this have any implications for humans?
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3. Pesticide exposures
Children of farm families in the western Minnesota area of the US have significantly higher rates of birth defects than the general population. The highest rates are among children conceived in the spring when spraying of pesticides is most intense; male babies had far more birth defects than females
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4. The end points may not only be cancer, but compromised immune systems and generally poorer health.
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4. Immune systems & Mothers milk
In the Netherlands researchers have found that children with higher levels of dioxins and PCBs in their bodies have more health problems (immune system and hormonal changes) than children with lower levels. This was linked to levels of PCBs in Mothers milk.
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4. Mothers milk
Overall, however, it was concluded that nursing was still of greater benefit than bottle feeding babies, but that even mild exposures may weaken immunity
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4. Mothers milk
Mothers milk from Inuit Indians in the Canadian Arctic has 7 times the PCBs as mothers milk from women in the urban industrialized areas of southern Quebec.
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4. Mothers milk
During the first year, Inuit babies suffer through 20 times more colds than babies in southern Quebec. Acute ear infections are rampant.
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4. Mothers milk
Babies nursed by mothers with the highest contamination levels in their milk are afflicted with more acute ear infections than bottle fed Inuit babies. Many of these children dont seem to produce enough antibodies for childhood vaccinations to take.
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5. PCBs and lower intelligence
There is evidence of lower intelligence in babies exposed to PCBs. In adults, a blood-brain barrier insulates the brain from many potentially harmful chemicals circulating through the body In a human child this barrier is not fully developed until 6 months after birth.
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5. PCBs and lower intelligence
In 1979 in Taiwan, more than 2000 people were exposed to PCBcontaminated cooking oil. In the 1st 3 months many babies died outright. As the surviving children grew up, many were slower intellectually than other kids their age, were hyperactive and had behavioral problems.
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5. PCBs and lower intelligence
Similar observations were made in "high-PCB kids" in the Lake Michigan area. This was associated with mothers eating salmon and trout from the Lake during the years before their children were born.
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5. PCBs and lower intelligence
At age 4 the high exposure group had poor short term memories. At age 11 the 30 most highly exposed kids had average IQ scores that were 6 points lower than the lowest-exposed group. biomarker-metabolites???
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6. DDT and immune system damage
In a recent study (1998), residents whose homes are within a mile of Aberdeen, Texas pesticide sites show elevated DDE levels in their blood.
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6. DDT and immune system damage
DDE is a byproduct of the bodys attempt to break down the pesticide DDT, which has been banned in the USA since 1972. Levels of plasma DDE in the study population overall were low (6ppb) compared to nationwide levels between 1976 and 1980, just after the DDT ban, (UNC, Prof. Vine)
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6. DDT and immune system damage
Younger Aberdeen residents those between ages 18 and 40 and people who lived there before 1985 when the plants were operating did show a twoto three-fold increased risk of herpes zoster, or shingles, which indicates modest suppression of the bodys immune system
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7. Sexual impairment
There is evidence for sexual impairment in both animals and humans from high PCB exposures and other environmental chemicals. Male beluga whales in the very polluted St. Lawrence River have exhibited female organs.
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7. Sexual impairment
Highly exposed humans, alligators and panthers exhibit smaller male sex organs and low sperm counts. Testicular cancers have nearly doubled among older teenagers in the US between 1973 and 1992. In previous lectures I have said these have been linked to toxic exposures....long way 82 from finding proof.
7a. Sexual impairment
In a new study (Hardwell et al, Environ Presp, 2003) woman whove had substantial exposure to certain environmental pollutants are more likely to bear sons who develop testicular cancers (men ~ 30 years of age) From 1973-1999 testicular cancers up 67% Men with test-cancers had high cis nona chloridane, not PCBs, etc Mothers, however, had high PCBs, HCB (hexachlorobenzenes) and cis nona chloridane 83
7b. Sexual impairment
These same mothers probably had high exposures when environmental contaminets peaked in Scandinavia in the 1970s Richard Sharpe of Edinburogh and Niels Skakkebek (Denmark) propose that exposure to endocrine disruptors before birth can alter testicular-cell development and some of these cells may be cancerous after puberty. This may also may explain rising rates of male infertility, and other sexual deformities
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8. Endocrine disrupters
These studies have led to the notion of environmental "endocrine disrupters". In the lock and key relationship between hormone and receptor molecules, these "hormone impostors" can:
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8. Endocrine disrupters
bind with receptors and trigger biological processes or bind with receptors and tie up an active hormone site Some of these have been called environmental estrogens
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9. Other chemicals
From a historical perspective, everyone is now carrying at last 250 measurable chemicals that were not part of human chemistry before the 1920s (Peter Myers, 1996) The most basic toxicity testing results cannot be found in the public record for nearly 75% of the top volume chemicals in commercial use in the USA
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9. Other chemicals
In other words, the public cannot tell whether a large majority of the highest-use chemicals in the United States pose health hazards or not (Amicus Journal, p23, Spring 1998).
An example are phthalates that go into many types of plastics which have been shown to reduce the sperm counts in mice.
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9. Other chemicals
Bisphenol-A (BPA) is an additive in polycarbonate plastics used in food liners, dental sealants, and dental fillings. BPA causes increased prostate size in mice exposed to tiny doses while in the womb. These doses were 25,000 times smaller than the EPA threshold.
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9. Phthalates
Exposure of female rates to 200 to 1000 mg/kg body weight results in much lower testosterone in male offspring ( L. Earl Gray. Jr. EPA, RTP, J. Tox and Ind. Health, Mar, 1999). Exposures to the herbicide linuron made the epididymis (sperm-storing organ in rats) much smaller in male rats.
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epididymus
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Recommendations
During the insecticide spraying season, farmers should not try to have children. Limit exposures to pesticides around the home. When possible, buy foods that were grown without pesticides. Governments must try to limit PCB introduction into the environment. If incineration is used, chlorinated plastics should be removed, along with modern technology.
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