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Envr 725Tues. and Thurs- 3 credit hours11 am to 12:15 pm

snow days call me at 942 4880 orcell 919 614 4730

room 0015 MHRChttp://www.unc.edu/courses/2007spring/envr/725/001/Envr725.html

Rich Kamens; 966 5452kamens@unc.eduhttp://airsite.unc.edu/~kamens/

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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 quantifyprocess 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 = γi Xipi*pure liquid

RT ln fi hx /fio

pure liq = RT lnfi H2O /fiopure liq

fi hx = fi H2O

ln Kp = a 1/T+b

6amb

ambmfusiL T

TTRS

pp is)()(

lnln ** −Δ+=

Vapor pressure

)]()( ln.*lnTT

TTp bb

iL 58119 +−=

How to calculate boiling points

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Vapor pressure and Henry’s law

K PC P Viaw

i

iwiw

satsat

satsat

iL*

iw= = γ

Solubility and activity coefficients

Octanol-water partitioning coefficients

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Additional PrinciplesOrganic 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, examsTo 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 problemswhich 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 IssuesGlobal 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

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?

Polynuclear Aromatic HC (PAHs)DioxinsKetonesPCBsCFCsDDTO3, NO2, aerosols, SO2

Some examples of environmental chemicals

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 dieselsc) open burningd) barbecued meat??

PAHs

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Combustion Formation of PAHBadger and Spotswood 1960

(I) (II) (III) (IV)

C

C

C

C

C

C

CC

CC

CC

(VII) (VI) (V)

Benzo a Pyrene

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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

Professor Gernot Grimmer extracted different types of smoke particlesHe then took the extract and applied it to mouse skinand implanted it into rat lungs

How did he obtain extracts?How did he fractionate his extracts??

Carcinogenic tests with PAHs

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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 withchemicalsfrom the particleson 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

HPLC

PAH 2&3 rings

Total

PAHs>3 rings

Total

Total-PAHs

uv orfluorescencedetector

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skin painted miceimplanted rat lungs

What did Grimmer see when exposed rats and mice to the different fractions?

0

10

20

30

40 %

can

cers

TotalTotal-PAHs

PAHs 2&3 ringsPAHs > 3 rings

rat lungs Mouse-skin

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Analysis of reaction products

soxhlet extraction for 3 hours– blow up with dry gentle flow of nitrogen to

about 0.5 to 1 mlevaporation to about 0.5 to 1 ml1 to 2 ul injected directly to GC-MS (EI and CI)The remainder solution: derivatization

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In environmental samples why don’t 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

FF

F

F F

CH2 O NH2

H2O

PFBHA

R1

C

O

R2

CH2

F F

F

FF

ONCR1

R2

acetone or ketone

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Pentafluorobenzyl bromide (PFBBr)derivatization for carboxylic and hydroxyl groups

CH2 C

O

OH

H3C CH3

C

O

H O

FF

F

F F

CH2Br

C CH2

O

HO C O CH2

F F

F

FF

OH3C CH3

HBr

PFBBr

C CH2

O

O C O CH2

F F

F

FF

OCH3 CH3

CH2

FF

F

F F

2 HBr

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BSTFA for carbonyl, hydroxyl, and/or carboxylicBSTFA

R OH

carboxylic acid or alcohol

C N

Si(CH3)3

CF3

O(CH3)3Si

C O

H2N

F3CRO(CH3)3Si

C NH

Si(CH3)3

CF3

O

+

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CompoundMw, g mol-1

Structure m /z (EI) CompoundMw, g mol-1

Structure m /z (EI)

α-Pinene oxideMw=152

67 (100)10983152

NopinoneMw=138

83 (100)5595109

β-Pinene oxideMw=152

79 (100)7141152

MenthoneMw=154

83 (100)56112140

Limonene-2-oxideMw=152

67 (100)9410879137

CamphoreMw=152

95(100)8110955152

d-LimoneneMw=136

9379136

MyrtenolMw=152

79 (100)91108152

2-Hydroxy-3-pinanoneMw=168

71 (100)99168

cis -VerbenolMw=152

94 (100)10981137

CineoleMw=154

84 (100)71108154139

trans -Pinane-1,10-diolMw=170

82 (100)675570152

MyrtenalMw=150

79 (100)107135150

trans -p-Menth-6-en-2,8-diolMw=170

109 (100)59 79

O

C O H

O

O

O

H

O HO

OC

C H O

OH

O

O

O H

C O H

HOOH

GC-EIMS for Oxygenated Terpenoids

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Thermal desorption particle beam mass spectrometry (Paul Ziemann)

Particle generator or smog chamber

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

Chlorinated dibenzo dioxins and Furans

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Combustion Formation of Dioxins from Polychlorinated phenol

O H

PolychlorinatedPhenol

Flame

OH .

.OO H

C ly

+

O

O H

+ OH

Chlorinated dibenzo dioxinClx

O

O

Shaub & Tsang, ES&T 1983.

Cly

Clx

ClxCly

Clx

They have the following general structures

O

O Clx

Cly chlorinated dioxin

They have the following general structures

O

O Clx

Cly chlorinated dioxin

O Clx

Cly chlorinated furan

The most toxic is either the 2,3,7,8 tetrachlorodibeno dioxin or furan

More than 200 different structures are possible

O

O

ClCl

Cl

Cl

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)

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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

0

100

200

300

400

500

600

700 U

S c

oal

in 1

0^6

shor

t-ton

s

0

200

400

600

800

10^6

lbs

Cl-a

rom

atic

s

1860 1880 1900 1920 1940 1960 1980 Year

Coal

chloro-aromatics

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Chlorinated aromatic production vs dioxinand furan conc. in lake core samples

0

200

400

600

800

1000

1200 To

tal d

ioxi

ns a

nd fu

rans

in p

pt

0

200

400

600

800

10^6

lbs

Cl-a

rom

atic

s

1900 1920 1940 1960 1980 Year

chlorinateddioxins andfurans

chloro-aromatics

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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.

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)/RTif resistance is in the gas phase

Polychlorinated biphenyls (PCBs)

RT ln fair /fiopure liquid = RT lnf H2O /fiopure liquid

fair = f H2O

In the late 1980s a fugacity model was used to represent the distribution of PCBs in different environmental compartments

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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.

used as coolants - insulation fluids in transformers, capacitors , plastercisers, additives to epoxy paintsare thermally stable and biologically stablecan exist in the gas and particle phases

Polychlorinated biphenyls (PCBs)

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Cl y

Cl x

PCB structures

Environmentally, they used to be considered unreactive, but there is evidence for some bio-degradation; they can be transported long distances

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 impossibleit 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

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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 life-time?

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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?

Si

O

Si

OSi

O

O

Si

O

Si

CH3

CH3CH3H3CCH3

H3C

CH3 CH3H3C H3C

Si

O

Si

OSi

O

O

Si

O

Si

CH3

CH3CH3H3CCH3

H3C

CH3 OHH3C H3C

D5 D4D'OHD4TOH

OH.

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.

Some examples of environmental exposures

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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 1980’s, 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.

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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 retardationstarted showing up in children.

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2. Toxic loads

Scientists have hypothesized that the fetus is sharing the mother’s 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 loadsIt 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 & Mother’s 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 Mother’s milk.

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4. Mother’s 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. Mother’s milk

Mother’s milk from Inuit Indians in the Canadian Arctic has 7 times the PCBs as mother’s milk from women in the urban industrialized areas of southern Quebec.

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4. Mother’s 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. Mother’s 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 don’t 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 PCB-contaminated 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 body’s 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 two-to three-fold increased risk of herpes zoster,

or shingles, which indicates modest suppression of the body’s 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 doubledamong older teenagers in the US between 1973 and 1992.

In previous lectures I have said these have been linked to toxic exposures....long way from finding proof.

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7a. Sexual impairment In a new study (Hardwell et al, Environ Presp, 2003) woman who’ve 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 nonachloridane, not PCBs, etc

Mothers, however, had high PCBs, HCB (hexa-chlorobenzenes) and cis nona chloridane

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7b. Sexual impairment These same mothers probably had high exposures when environmental contaminetspeaked in Scandinavia in the 1970s

Richard Sharpe of Edinburogh and NielsSkakkebek (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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RecommendationsDuring 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.