3 Major health issues May seem more important today than in the past In part because of so many peopleBut are not new to the planet
4 Toxicity What is toxic? Chronic Acute Can rank toxicity Some things are much more toxic than other, but . . .Varies depending on individualagehealthgenes
5 Dose-response Some things are bad for you - How much before harm is done?Some things are good -How much is too much?Too much of agood thing
6 Lab tests Expose animals to potential toxics See how many die or get cancer or …Depending on dosageLD50 = lethal dose for half the populationOf courseTough to translate to humansAnd we can’t do human experimentsBut, experiments confirm that very small amounts can be very bad
7 Top 10 most toxic substances (arguably) and estimated LD50 for 200 lb person based on lab experiments on various mammalstetanus (bacteria) μgbotulinal neurotoxin (bacteria) μgshigella (bacteria) μgpalytoxin (coral) μgdiphtheria (bacteria) μgricin (from castor beans) μgaflatoxins (mold which grows on nuts, legumes, seeds) 0.1 μgsaxitoxin (shellfish) μgtetrodotoxin (fugu pufferfish) μgdiphtheria (bacteria) μg1 grain of salt is about 60 micrograms (μg)
8 Cancer and related problems CarcinogensCause cancerMalignantmelanoma
9 Cancer and related problems MutagensCause mutation
10 Cancer and related problems TeratogensCause birth defectsTwo-headedkittenCancer, mutation, birth defectscaused by exposure to toxicsBut often hard to tell whichSome, such as cigarettes,are obvious
11 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 humansExamplesDDT - pesticidesPCBs - transformersBisphenol A – epoxy, plasticsPDEs - solventsPhthalates - plasticsMany othersMale 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.
12 What are the risks/costs/odds? Risk-benefitHard to evaluate riskAnd, how safedo we want to be?Cost-benefitWhat is a human life worth?And, what is the costof not doing something?Precautionary principleOne major problem is that we knowthere are synergies, and antagonisticinteractions -- but it is almostimpossible to evaluate them.
13 Started really being Concerned about Hazardous waste Because . . . 1977 Love CanalNiagara Falls New YorkChemical company and school boardReally brought concerns to forefrontDioxinsNext major issueForm during chemical manufacturing involving chlorine-bearing compoundsAlso comes from burning waste that contains chlorine in dumps or backyardsAlso produced by paper mills, production of PVC plastic, and other industriesTimes Beach MO 1970sPCBsPCBs are also chlorine-containing compoundsOnce used as coolants, flame retardants, lubricants . . .Now banned in USManufacturers knew PCBs causes health problems since the 1930s and 1940sMany reports of serious health problemsDid not become real concern until 1970sChlorine is a keycomponent in manytoxics – plastics,pesticides, etc.
14 Hazardous waste So, we have RCRA 1976 CERCLA and Superfund 1980 Requires cradle to grave tracking of toxicsCERCLA and Superfund 1980Passed in response to Love CanalAnd dioxin at Times BeachAnd other such lawsSuperfund sites in USAs of January 2013, there were 1,312 NPL sites in the U.S.None in North Dakota any longerSince 1980, <300 taken off the list
15 But, many things we encounter in our daily lives are toxic PesticidesIndustrial chemicalsPVC, etc.And moreAnd . . .Even cautious use releases some stuff to the environment
16 Toxics are all around us: plastics polystyreneHDPEPVCPETpolypropyleneLDPEWhen we use them, we absorb some although generally in small amounts.
17 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” safetyWhich cannot be done
18 PVCIn 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 productsPVC 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.
19 PETSoft drink, juice, water, beer, mouthwash, peanut butter, salad dressing, detergent and cleaner containersLeaches 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.
20 PS = polystyreneIn 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.
21 HDPEIn opaque milk, water, and juice containers, bleach, detergent and shampoo bottles, garbage bags, yogurt and margarine tubs, cereal box linersResearch on risks associated with this type of plastic is ongoing
22 LDPEIn 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 ongoingNalgene
23 PP = polypropyleneIn ketchup bottles, yogurt and margarine tubs, medicine and syrup bottles, straws, opaque plastic storage containers, baby bottles, clothingResearch on risks associated with this type of plastic is ongoing.
24 PC = polycarbonateIn 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, computersPolycarbonate 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.
25 Cancer rates Seem to be higher today Men Women Diet Life style EnvironmentMenProstateLung – accounts for 75% of deathsColorectalWomenBreastLung – accounts for 40% of deathsCancer clusters?
26 Cancer Worldwide – about 12% of deaths are due to cancer US has highest cancer rates in the world4 in 10 people in US get cancer todayExpected to increase in next decadeDue to continued smokingAging populationWe have many products, including food, that contain toxicsAnd especially poor diet and unhealthy lifestylesBrain cancer cells
28 How should we handle toxics? Ideally – use them safelyBut, we don’t know what that is, and . . .Routine use poses riskEven if only a little escapes into the environment . . .Small doses can be very badFor many toxics we don’t know riskSynergies and bioaccumulation not understoodSkeptics say we must prove riskBefore doing anythingPrecautionary Principle says the opposite
29 Sadly, we mostly only act after catastrophe e.g., Superfund after Love Canal and Times Beach
30 Pollution and human health Are things getting better or worse?Cancer has reached epidemic proportionsBillions of pounds of chemicals escape each yearOther new things causing alarmEndometriosisEmerging new problem affecting women’s uterusADD/ADHD3% more victims each yearAsthmaDoubled between 1980 and 1996Sperm countsFalling rapidly
31 Pollution and human health What is cause of increase in problems?No certain answers but most experts say1. exposure to toxics2. lifestylesFor example food is routinely sprayed with pesticides whose safety is in questionPesticide residues show up on all foods unless organicDelaney clause says no carcinogens can be in foodBut is not well enforced
32 Could problems be genetic, not environmental? Study identical twinsFind that breast cancer rates do not matchInstead correlate with environmental factorsStudy adopted childrenFind that cancer rates do not correlate with biological parentsInstead with adopted parents and exposure to toxics
33 Why not do something? We do, sometimes: e.g., Delaney Clause But delays caused by:Scientific uncertaintyEconomic costAnd, sadly:Things may be worse than we thinkIf we delay, it could be too lateEven worse:Politics: Government often will not do it even when it is clear that action is needed
34 And, what about (“natural”) diseases Lyme disease
35 And, what about (“natural”) diseases Novel infections seem more common these daysNot necessarily due to toxics but there could be a connectionIn part probably due toBetter detectionPeople no longer die of unknown causesPeople travel a lot moreFood and other things are shipped all overOveruse of antibiotics meansOrganisms are more virulent and resistant
36 New (“emerging”) and old diseases Legionnaire’s disease 1976Caused by bacteria living in air conditionersMany people very illHalf died
37 New (“emerging”) and old diseases Legionnaire’s 1976AidsFirst recognized in 198130 million people infected worldwideMost in AfricaDue to HIV virusMany new drugsProlong lifebut most victims still die
38 New (“emerging”) and old diseases Legionnaire’sAidsExotic diseases from AfricaLhasa feverEbola virusMarburg infection
39 New (“emerging”) and old diseases Legionnaire’sAidsLhasa feverEbola virusMarburg infectionLyme disease
40 New (“emerging”) and old diseases Legionnaire’sAidsLhasa feverEbola virusMarburg infectionLyme diseaseHanta virusFrom KoreaKilled people in southwest US in 1993
41 New (“emerging”) and old diseases Legionnaire’sAidsLhasa feverEbola virusMarburg infectionLyme diseaseHanta virusSome old diseasesseem to be coming back:MalariaTuberculosisIn part because they are becoming resistant to antibiotics
44 Food poisoning E coli Botulism Campylobacter Salmonella Widespread organismMany different typesSome very badMost associated with sewageE coliBotulismCampylobacterSalmonellaMostly due to improper food handlingFound in raw poultry and meat,Unpasteurized milk, untreated waterMost common identified form of food poisoningFound in raw poultry, dairy and meat,and unwashed vegetables,In the gut and feces of animals and humans
45 Food poisoning E coli Botulism Campylobacter Salmonella All of these got much worse because of:Large centralized food production facilitiesIntensive feed lots and agricultureOveruse of antibiotics, etc“Big box” food stores
46 mortality today In HDC countries Sanitation and drugs help Disease and pathogens (mostly) under controlIn U.S., leading causes of death: heart disease, cancerNon-infectious, chronic, associated with lifestyle and agingNot so In LDC countriesMalnutritionSanitationWater suppliesAir pollution many infectious disease problemsCholera occurrences
47 Should we be scared? Some people worry about pandemics There are some warning signs
48 Should we be scared? Aids Out of Africa Most cases in Africa Many in USMany others in India, Asia, etc.Not curable, but can be slowed
49 Should we be scared? BSE Bovine spongiform encephalopathy a.k.a. mad cow diseaseDisease in cattleEspecially in UKMay be transmitted to peopleLeads to Creutzfeldt-Jakob diseaseCauses brain degeneration in peopleContributing cause is that cattle are fed meat and bone meal, causing disease to spreadNot necessary because cattle are herbivoresBut cattle operators make more profits if fattened with animal based feed
50 Should we be scared?BSELed to slaughter of entire British dairy industry in late 1980sBut spread to CanadaSo, temporary bans put on importing Canadian beefSo, how bad is it?
51 Should we be scared? Swine flu a.k.a. pig flu or pig influenza Common in pigsEspecially pigs in feed lotsSo, operators give lots of antibiotics to pigsWhich are the same antibiotics humans useSo, super strains of flu and other pathogens develop that are antibiotic resistantPigs dieAnd humans catch disease that originated in pigsCDC has warned for years that we need to stop giving antibiotics to livestockBut intensive livestock operations need itSo pig/cattle operators make more profitsSo, how bad is it?
52 But, so far, these disease risks are small compare with risks from . . . CancerSecond leading cause of death in US (following heart disease)Many different kinds (>200)Can start in any type of body tissueNot a pandemicMany factors contributeMost importantTobaccoDiet/weight/physical activityUltraviolet radiationCarcinogens
53 So . . .Don’t smoke(There are lots of reasons not to smoke besides cancer . . .)Eat healthy foods and get exercise
55 Avoid carcinogens? Carcinogens include Antiperspirants Talcum powder Hair dyes, cosmetics, and almost everything else in a beauty salonDry cleaning fluidInsect sprayFood ingredients: aspartame, bovine growth hormone, artificial colors and flavorsAnd many more common product ingredients
56 Everything causes cancer . . . ? They say:A cop outExcuse not to think about a very complex problemSome things are known to be carcinogens (or possibly to be carcinogens)Others are notWhich do you want in your life?
57 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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