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HUMAN HEALTH AND TOXICOLOGY

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Major health issues• May seem more important today than in the past• In part because of so many people

But are not new to the planet

TOXICITY

What is toxic? Chronic Acute

Can rank toxicity Some things are much more toxic than

other, but . . . Varies depending on individual

age health genes

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DOSE-RESPONSE

Too much of agood thing

Some things are bad for you -How much before harm is done?

Some things are good -How much is too much?

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LAB TESTS

Expose animals to potential toxics See how many die or get cancer or … Depending on dosage

LD50 = lethal dose for half the population

Of course Tough to translate to humans

And we can’t do human experiments

But, experiments confirm that very small amounts can be very bad

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TOP 10 MOST TOXIC SUBSTANCES (ARGUABLY)AND ESTIMATED LD50 FOR 200 LB PERSONBASED ON LAB EXPERIMENTS ON VARIOUS MAMMALS

tetanus (bacteria) 0.1 μgbotulinal neurotoxin (bacteria) 0.1 μgshigella (bacteria) 0.1 μgpalytoxin (coral) 6 μgdiphtheria (bacteria) 10 μg ricin (from castor beans) 0.1 μgaflatoxins (mold which grows on nuts, legumes, seeds) 0.1 μgshigella (bacteria) 0.1 μgsaxitoxin (shellfish) 0.3 μg tetrodotoxin (fugu pufferfish) 1 μgdiphtheria (bacteria) 0.2 μg

1 grain of salt is about 60 micrograms (μg)

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CANCER AND RELATED PROBLEMS

Carcinogens Cause cancer

Malignantmelanoma

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CANCER AND RELATED PROBLEMS

Mutagens Cause mutation

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CANCER AND RELATED PROBLEMS

Teratogens Cause birth defects Two-headed

kitten

Cancer, mutation, birth defects caused by exposure to toxics

But often hard to tell which

Some, such as cigarettes, are obvious

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ENDOCRINE DISRUPTERS

Act like hormones in the endocrine system Cause cancer, reduced sperm counts, immune problems . . .

Definitely affect animals – what about people? Very difficult to determine dose-response for humans Examples

DDT - pesticides PCBs - transformers Bisphenol A – epoxy, plastics PDEs - solvents Phthalates - plastics Many others

Male sperm counts have decreasedall around the world during the past15-20 years.

Cause is unknown.

But, at this rate there will be widespreadinfertility within decades.

Many suspect endocrine disruptors are the cause.

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WHAT ARE THE RISKS/COSTS/ODDS? Risk-benefit

Hard to evaluate risk And, how safe do we want to be?

Cost-benefit What is a human life worth? And, what is the cost of not doing something?

Precautionary principle

One major problem is that we knowthere are synergies, and antagonisticinteractions -- but it is almostimpossible to evaluate them.

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STARTED REALLY BEING CONCERNED ABOUT HAZARDOUS WASTE BECAUSE . . .

1977 Love Canal Niagara Falls New York Chemical company and school board Really brought concerns to forefront

Dioxins Next major issue Form during chemical manufacturing involving chlorine-

bearing compounds Also comes from burning waste that contains chlorine in

dumps or backyards Also produced by paper mills, production of PVC plastic, and

other industries Times Beach MO 1970s

PCBs PCBs are also chlorine-containing compounds Once used as coolants, flame retardants, lubricants . . . Now banned in US Manufacturers knew PCBs causes health problems since the

1930s and 1940s Many reports of serious health problems Did not become real concern until 1970s

Chlorine is a keycomponent in manytoxics – plastics,pesticides, etc.

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HAZARDOUS WASTE So, we have

RCRA 1976 Requires cradle to grave tracking

of toxics CERCLA and Superfund 1980

Passed in response to Love Canal And dioxin at Times Beach

And other such lawsSuperfund sites in US

• As of January 2013, there were 1,312 NPL sites in the U.S.

• None in North Dakota any longer

• Since 1980, <300 taken off the list

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BUT, MANY THINGS WE ENCOUNTER IN OUR DAILY LIVES ARE TOXIC

Pesticides Industrial chemicals PVC, etc. And more

And . . . Even cautious use releases

some stuff to the environment

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TOXICS ARE ALL AROUND US: PLASTICS

HDPEPVC

PET

LDPE

polypropylene

polystyrene

When we use them, we absorb some . . . although generally in small amounts.16

PLASTICS IN FOOD

FDA says all plastics put toxics in our food

Question is: how much, and how much is bad?

Manufacturers are required to “prove” safety

Which cannot be done

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PVC

In toys, clear food and non-food packaging (e.g., cling wrap), some squeeze bottles, shampoo bottles, cooking oil and peanut butter jars, detergent and window cleaner bottles, shower curtains, medical tubing, and numerous construction products

PVC has been described as one of the most hazardous consumer products ever created. PVC leaches di(2-ethylhexyl) phthalate (DEHP) or butyl benzyl phthalate (BBzP), depending on which is used as the plasticizer or softener (usually DEHP). DEHP and BBzP are endocrine disruptors mimicking the female hormone estrogen. This type of plastic has been strongly linked to asthma and allergic symptoms in children; may cause certain types of cancer; is linked to negative effects on the liver, kidney, spleen, bone formation and body weight. In Europe, DEHP and BBzP and other dangerous pthalates have been banned from use in plastic toys for children under three since 1999.

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PET

Soft drink, juice, water, beer, mouthwash, peanut butter, salad dressing, detergent and cleaner containers

Leaches antimony trioxide: workers exposed to antimony trioxide for long periods of time have exhibited respiratory and skin irritation; among female workers, increased incidence of menstrual problems and miscarriage. The longer a liquid is left in such a container, the greater the concentration of antimony is released into the liquid.

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PS = POLYSTYRENE

• In styrofoam containers, egg cartons, disposable cups and bowls, take-out food containers, plastic cutlery, and compact disc cases.

• Polystyrene leaches styrene, which is an endocrine disruptor mimicking the female hormone estrogen, and thus has the potential to cause reproductive and developmental problems. Long-term exposure by workers has shown brain and nervous system effects. Polystyrene is also present in secondhand cigarette smoke, off-gassing of building materials, and car exhaust. Styrene migrates significantly from polystyrene containers into the container’s contents when oily foods are heated in such containers.

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HDPE

In opaque milk, water, and juice containers, bleach, detergent and shampoo bottles, garbage bags, yogurt and margarine tubs, cereal box liners

Research on risks associated with this type of plastic is ongoing

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LDPE

In grocery store, dry cleaning, bread and frozen food bags, most plastic wraps, squeezable bottles (honey, mustard)

Research on risks associated with this type of plastic is ongoing

Nalgene

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PP = POLYPROPYLENE

In ketchup bottles, yogurt and margarine tubs, medicine and syrup bottles, straws, opaque plastic storage containers, baby bottles, clothing

Research on risks associated with this type of plastic is ongoing.

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PC = POLYCARBONATE

In most plastic baby bottles, clear plastic “sippy” cups, hard “sports” water bottles, three and five gallon large water storage containers, metal food can liners, some juice and ketchup containers, compact discs, cell phones, computers

Polycarbonate leaches Bisphenol A (some effects described above), and numerous studies have indicated a wide array of possible adverse effects from low-level exposure to Bisphenol A including chromosome damage in female ovaries, decreased sperm production in males, early onset of puberty, various behavioral changes, altered immune function, and sex reversal in frogs.

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CANCER RATES

Seem to be higher today Diet Life style Environment

Men Prostate Lung – accounts for 75%

of deaths Colorectal

Women Breast Lung – accounts for 40%

of deaths Colorectal

Cancer clusters?

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CANCER

Worldwide – about 12% of deaths are due to cancer

US has highest cancer rates in the world 4 in 10 people in US get cancer today Expected to increase in next decade

Due to continued smoking Aging population We have many products, including food, that contain toxics And especially poor diet and unhealthy lifestyles

Brain cancer cells

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WHY CANCER CLUSTERS?

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Prostate cancer

HOW SHOULD WE HANDLE TOXICS?

Ideally – use them safely But, we don’t know what that is, and . . . Routine use poses risk Even if only a little escapes into the environment . . . Small doses can be very bad For many toxics we don’t know risk Synergies and bioaccumulation not understood

Skeptics say we must prove risk Before doing anything

Precautionary Principle says the opposite

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Sadly, we mostly only act after catastrophe

e.g., Superfund after Love Canal and Times Beach

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POLLUTION AND HUMAN HEALTH

Are things getting better or worse? Cancer has reached epidemic proportions Billions of pounds of chemicals escape each year Other new things causing alarm

Endometriosis Emerging new problem affecting women’s uterus

ADD/ADHD 3% more victims each year

Asthma Doubled between 1980 and 1996

Sperm counts Falling rapidly

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POLLUTION AND HUMAN HEALTH What is cause of increase in problems? No certain answers but most experts

say 1. exposure to toxics 2. lifestyles

For example food is routinely sprayed with pesticides whose safety is in question

Pesticide residues show up on all foods unless organic

Delaney clause says no carcinogens can be in food

But is not well enforced

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COULD PROBLEMS BE GENETIC, NOT ENVIRONMENTAL?

Study identical twins Find that breast cancer rates do not match Instead correlate with environmental

factors Study adopted children

Find that cancer rates do not correlate with biological parents

Instead with adopted parents and exposure to toxics

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WHY NOT DO SOMETHING?

We do, sometimes: e.g., Delaney Clause

But delays caused by: Scientific uncertainty Economic cost

And, sadly: Things may be worse than we think If we delay, it could be too late

Even worse: Politics: Government often will not do it even

when it is clear that action is needed

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AND, WHAT ABOUT (“NATURAL”) DISEASES

Lyme disease

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AND, WHAT ABOUT (“NATURAL”) DISEASES

Novel infections seem more common these days

Not necessarily due to toxics but there could be a connection

In part probably due to Better detection People no longer die of unknown causes People travel a lot more Food and other things are shipped all over Overuse of antibiotics means

Organisms are more virulent and resistant

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NEW (“EMERGING”) AND OLD DISEASES Legionnaire’s disease 1976 Caused by bacteria living in air conditioners Many people very ill Half died

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NEW (“EMERGING”) AND OLD DISEASES Legionnaire’s 1976 Aids

First recognized in 1981 30 million people infected worldwide Most in Africa Due to HIV virus Many new drugs

Prolong life but most victims still die

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NEW (“EMERGING”) AND OLD DISEASES Legionnaire’s Aids Exotic diseases from Africa

Lhasa fever Ebola virus Marburg infection

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NEW (“EMERGING”) AND OLD DISEASES Legionnaire’s Aids Lhasa fever Ebola virus Marburg infection Lyme disease

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NEW (“EMERGING”) AND OLD DISEASES Legionnaire’s Aids Lhasa fever Ebola virus Marburg infection Lyme disease Hanta virus

From Korea Killed people in southwest US in 1993

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NEW (“EMERGING”) AND OLD DISEASES Legionnaire’s Aids Lhasa fever Ebola virus Marburg infection Lyme disease Hanta virus Some old diseases seem to be coming back:

Malaria Tuberculosis

In part because they are becoming resistant to antibiotics41

FOOD POISONING

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FOOD POISONING

E coli Botulism Campylobacter Salmonella Bovine spongiform

encephalitis (BSE)

bacteria

bacteria

bacteria

bacteria

protein

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FOOD POISONING

E coli Botulism Campylobacter Salmonella

• Widespread organism• Many different types• Some very bad• Most associated with sewage

• Mostly due to improper food handling

• Found in raw poultry and meat,• Unpasteurized milk, untreated

water• Most common identified form of

food poisoning

• Found in raw poultry, dairy and meat,

• and unwashed vegetables,• In the gut and feces of animals

and humans

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FOOD POISONING

E coli Botulism Campylobacter Salmonella

• All of these got much worse because of:• Large centralized food production facilities• Intensive feed lots and agriculture• Overuse of antibiotics, etc• “Big box” food stores

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MORTALITY TODAY

In HDC countries Sanitation and drugs help Disease and pathogens (mostly) under control In U.S., leading causes of death: heart disease, cancer

Non-infectious, chronic, associated with lifestyle and aging

Not so In LDC countries Malnutrition Sanitation Water supplies Air pollution many infectious disease problems Cholera occurrences

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SHOULD WE BE SCARED?

Some people worry about pandemics There are some warning signs

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SHOULD WE BE SCARED?

Aids Out of Africa Most cases in Africa Many in US Many others in India, Asia, etc. Not curable, but can be slowed

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SHOULD WE BE SCARED? BSE

Bovine spongiform encephalopathy

a.k.a. mad cow disease Disease in cattle Especially in UK May be transmitted to people Leads to Creutzfeldt-Jakob

disease Causes brain degeneration in

people Contributing cause is that cattle

are fed meat and bone meal, causing disease to spread

Not necessary because cattle are herbivores

But cattle operators make more profits if fattened with animal based feed

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SHOULD WE BE SCARED? BSE Led to slaughter of entire

British dairy industry in late 1980s

But spread to Canada So, temporary bans put on

importing Canadian beef

So, how bad is it?

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SHOULD WE BE SCARED? Swine flu

a.k.a. pig flu or pig influenza Common in pigs Especially pigs in feed lots So, operators give lots of antibiotics to

pigs Which are the same antibiotics humans

use So, super strains of flu and other

pathogens develop that are antibiotic resistant

Pigs die And . . . humans catch disease that

originated in pigs CDC has warned for years that we need

to stop giving antibiotics to livestock But intensive livestock operations need

it So pig/cattle operators make more

profits

So, how bad is it?51

BUT, SO FAR, THESE DISEASE RISKS ARE SMALL COMPARE WITH RISKS FROM . . .

Cancer Second leading cause of death in US

(following heart disease) Many different kinds (>200) Can start in any type of body tissue Not a pandemic Many factors contribute

Most important Tobacco Diet/weight/physical activity Ultraviolet radiation Carcinogens

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SO . . . Don’t smoke (There are lots of reasons not to

smoke besides cancer . . .) Eat healthy foods and get exercise

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COSMETICS AND OTHER BEAUTY PRODUCTS

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AVOID CARCINOGENS? Carcinogens include

Antiperspirants Talcum powder Hair dyes, cosmetics, and

almost everything else in a beauty salon

Dry cleaning fluid Insect spray Food ingredients: aspartame,

bovine growth hormone, artificial colors and flavors

And many more common product ingredients

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EVERYTHING CAUSES CANCER . . . ?

A cop out Excuse not to think about

a very complex problem Some things are known to

be carcinogens (or possibly to be carcinogens)

Others are not Which do you want in your

life?

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They say:

SO, SHOULD YOU BE WORRIED?

Only if you haven’t thought about these issues . . .

And don’t plan to think about them now.

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