Science of Environmental Risk


Hi all Dr. Clark here again today for
natural resources we’re going to talk about environmental risk so we talked
about environmental health we talked about toxicology and now we’re going to
talk about the science of environmental risk where’s the science behind things
like heavy-metal bioaccumulation or toxic chemicals in the water system
and and things like that how do scientists evaluate these systems what
are the regulations around some of these and just kind of a brief overview of how
scientists go about environmental risk estimates okay so first of all we’re
going to talk a little bit about bioaccumulation so bioaccumulation
happens when often happens when things like nonpolar toxins are stored in fat
so it can also happen with polar substances but often it’s nonpolar
substances gets stored in fat tissue of different organisms and it accumulates
now from small organisms to large organisms and the effects accumulate on
that so for example let’s say we have a toxin like DDT which was used to be used
to as an insecticide on fields and you know in the 50s it was created and in
the 40s for World War 2 but then when after World War 2 DDT was used for a
good period because it’s an excellent insecticide I mean it kills all the
insects but it can accumulate in the bottom of rivers and streams and lakes
and things like that small insects can then pick it up and that really does
nothing to the small insects after it’s you know in the system does really
nothing to them fish then eat those small insects fish it depends on the
fish species times they’ll have some effects to the
fish species but then the birds will eat the fish and then you get this huge
accumulation in the tissues this is exactly what was happening to
fish-eating birds in the 60s when you know books like Silent Spring Rachel
Carson’s work on you know birds came out when Jim Greer’s work on bald eagles
came out it was due to you know DDT their work was mainly DDT work but it
was because the bioaccumulation was happening at these higher trophic levels
so where you weren’t seeing much science in the fish and the insects in the
system that’s what we were looking we knew the runoff was going out of the
fields so we check on the fish and the insects and stuff in these water systems
and there wasn’t a huge affect on them but we we had to draw that connection
between that and say bald eagle nesting and what happens when DDT accumulates in
the tissue it gets into the bird system and then it gets it reacts with the
capability of the bird to lay down shell material on the eggs and so it caused
the egg shells to be really thin and so the egg would come out very very thin
and sometimes it come out and just you know shatter when it hits the nest okay
but other times the burden moves on the nest or it might just barely touch it
with their toe and it would shatter the egg and the eggs were so porous and so
devoid of calcium that they’re just falling apart and that’s when you know
we saw huge declines and birds that eat fish and the connection between that was
drawn by Carson and and Jim Greer and a bunch of other biologists in the 60s so
bioaccumulation is you know that toxins accumulating in the tissue okay
biomagnification is normally when those toxins accumulate and become a burden a
more toxic to the individual as you move up trophic levels okay and so you can
get accumulation and biomagnification working together like DDT where you
accumulate these concentrations and eventually over time the toxicity builds
up and then it becomes toxic alright persistence so persistence is
basically like I talked about before the half-life the chemical or how long does
a chemical persist in the environment is it persisting in the tissues like the
fatty tissues of organisms is a persisting in the soil does a persistent
plants and you know how long is it stable in the environment when we’re
creating chemicals for herbicides and pesticides and things like that we want
them to degrade very rapidly okay we don’t want them to buyout cumulating bio
magnified at all and we already learned our lesson with DDT well I hope but so
most modern pesticides they they degrade very rapidly once once they’re in the
system what they’re exposed to water and things like that now there are things
though that we still constantly use that have you know persistence for a long
time metals and whether that be LED or you know mercury is still used in some
such systems so there are definitely metals that can leach into aquatic
systems and persist for a long period of time but I think the main system that
we’re interested now or Baxter PPA BPA’s and that’s particulate
matter that’s normally coming off of plastics and so whether that D actually
be physically the plastic or the chemicals that are laid to keep plastic
from deteriorating and things like that they can be toxic and they can be stored
in the environment for a long period of time I mean for example we’re you know
there’s a lot of restaurants and a lot of places that are banning straws and
some of these well these straws have BPA’s and so they do persist in the
environment for a long period of time and you know it’s really coming about
from you know the photographs of tortoises and things like that that got
straw straw stuck in their nose and and whatnot but even more than that the
science suggests even once the straw breaks down you still have my neat
microscopic plastic particles all over in the environment that can you know
bind up other organisms bodies so you know insects and things like that that
can digest these they can’t actually break them down so they’ll bring it into
the system but they can’t get rid of it sometimes they you know binds up and you
can find these BPA’s in the system much longer so other persistent organic
pollutants that we’ve seen issues with things like flame retardants whether
that be clothing or just materials and walls or coatings that go on to
different things we know that they can be extremely harmful for the nervous
system and and now we’re seeing it all over the world that be peds are
persistent and we use them mainly in flame flame returns to prevent fire
other things that you know we now know it was a good idea when we had a
nonstick plastic coatings they’ll be seen like pans and things like that they
can definitely cause liver damage and are known carcinogens they can persist
in your blood for a long period of time in the environment in the water system
for a long period of time and so you’ll start to see that these nonstick plastic
coatings at least certain types of them are no longer used but like I said
before it really takes this we utilize these it was a good idea you know
different types of flame retardants and the different plastic coatings and
things were good ideas they make people’s lives much more advantageous to
have these things around but it takes a few years – for us to find whoa hold on
a second when they break down just a little bit even their huge problem and
they can really be a health pollutant violates these are again you know found
in plastics and they can mimic our estrogen and they can increase you know
estrogen and males which can cause them to you know be more female like we’ve
seen this a lot in animals like frogs and things like that but there is some
evidence that suggests that has a direct effect on humans – so there’s lots of
ways that these things work and one way that we’re more interested in when we
talk about the science of toxicology or the science of environmental health
really comes with chemical interaction this is kind of the new kind of process
– to wrap our minds and wrap our hands around these ideas of you know chemicals
that we’re using constantly every day to preserve things to store things you know
to make things smoother so coatings and things
that what happens to them when they break down and so you can have different
types of reactions you know like antagonists reactions where one material
will interfere and affect another material so you might have a material
that causes another material to break down when they come into contact with
each other you can have additive reactions where two chemicals that
normally aren’t you know normally not together but when they come together
they have an additive effect which can be toxic and then you can have
synergetic reactions things like you know asbestos and smoking so you know
asbestos exposure increase the risks of lung cancer by 20 percent or 20 times
sorry and smoking is 20 times also but when you combined someone who works with
removal of asbestos and they’re exposing themselves to that and they smoke there
about a 400 times the risk of a normal individual from the for developing lung
cancer it’s almost a guarantee pretty much that you’re going to develop lung
cancer if you’re a smoker and you work with asbestos
these are synergetic centered gistic reactions where they’re multiplied so
they multiply the toxicity of whatever it is and so you know this this example
is well-documented and all asbestos workers should be getting in the
document that says you know you are at risk developing lung cancer if you work
with asbestos if you smoke your risk is now this
that’s pretty well-documented piece of information so we often want to
introduce ways at which we can minimize the toxic effect we know that we’re
exposing ourselves to toxicities constantly every single day I mean from
you know a candy bar with a plastic wrapper on it you know how much of this
exposure from just being in a plastic wrapper is an issue or you know the
drinking water that you’re getting out of drinking fountain or out of your tap
what kind of exposure are you exposing yourself to is it better to drink
bottled water which has BPA’s in it or has the potential that BPA is in it you
know it depends it depends on the individual and so we often are
interested in will minimizing the toxic effects of things and like I said before
every material can be toxic or poisonous under certain conditions you know you
can actually poison yourself with water you could drink enough water that you
could kill yourself you can drown yourself in the water so even the most beneficial product probably on the
planet water it can be poisonous at certain concentrations now the issue
often is can we keep these toxins under a certain threshold and so we need to
set thresholds and that’s what you know scientific environmental health agencies
and organizations like the EPA they set certain thresholds based on laboratory
research on mice and rats and things like that and frogs and other things
they set these scientific thresholds and we need to be under those sometimes it’s
wrong I’m not gonna I’m not gonna I’m not going to sugarcoat it in any of any
way sometimes that threshold is not correct mice are a good model for humans
but they’re not a perfect fit for us and so when we concentrate on doing
these laboratory studies to look at toxic
effects we’re doing it with laboratory animals not on humans and humans have
different metabolisms there are different exposures to different things
and we’re often also not not figuring out well what’s the cumulative effect so
maybe we’re after I knew maybe as a new plastic coating a new polymer that we’ve
developed and we’re looking at the toxic effects well what happens if you you
know scrape a little of that off and you mix it with this other polymer we often
don’t do those kind of experiments we don’t do the additive experiments which
can be really concerning because that’s what’s going to happen in real life
you’re not just going to be exposed to one chemical one toxin you’re gonna be
exposed to many toxins at the same time often and through many different sources
of material so you know we can look at metabolic degradation and this is often
how we do these kind of studies we take mammals typically mice or rats and we
expose them to different toxins and then we look at how degraded or how much
degradation their liver has had over a certain period of time we also try in
some cases to reverse the process so is there ways at which you can
reverse it so if you supply and apply this toxin to the individual and then
you remove that toxin so a good example is like Flint Michigan so exposure to
lead in the water system these kids are all exposed to it not knowing the danger
of of the system they’re exposed to it now let’s say the water is clean I’m not
saying the water is clean you okay because there’s reports that say it’s
not clean but let’s say that water gets cleaned up and the kid you know
is now you know was two years old and now they’re six years old four years
later we finally get the water system cleaned up is that individual going to
recover over their lifetime or do you get these degradation that happened for
those four years or really for the exposure of one year was that enough to
cause a toxic effect a detrimental effect to the individual for the rest of
their life we try to do that in the laboratory with mice and we’re often
interested in in those products where like I said before you know this product
is a great product maybe it’s a new product and it’s been tested the product
itself been tested many times and it passes with flying colors great it’s
good stuff but then it breaks down over a long period of time or over some other
chemical being exposed to it it breaks down and now it produces a harmful
chemical or a toxic chemical and those are ones that were really interested
excretion and repair like I said before if these are hydrophilic toxins a lot of
times they can be excreted through the urine of an individual this can be
helpful but this can also be detrimental depending on where that toxin is being
excreted into if it’s excreted into a sanitary system like we have in
developed countries that’s probably good okay that water’s going to be treated
before it’s dumped into the river if it’s excreted into a non sanitary center
form so it’s just extreme it goes directly into the water source and then
it’s drink again this can be a huge issue or if it’s excrete mint from wild
or from domesticated animals wild animals are going to drink that up
there’s lots of situations where the environmental toxins can be excreted but
then picked up and cause even more problems
you can also excrete things by breathing so you excrete carbon dioxide we excrete
some of the chemicals that you would be picking up from air and you can excrete
it right back out now I talked about this a little bit before when I talked
about mutagens so we have a DNA repair system that’s called p53 protein 53 and
that is a repair system that looks at your DNA and looks for mistakes in your
DNA it looks for thymine dimers or just wrong base pairings and then it’ll turn
on a repair system repair enzymes to come in and cut that out put new stuff
in so we have these built in repair systems sometimes though the exposure to
different things different toxins and different carcinogens and things like
that can affect the repair system so if you break the repair system then there
is no repair going on and you can develop cancer and lead to cancer and so
that’s often well what we’re really concerned with when it comes to
carcinogens is what’s the chance that the carcinogen will affect the repair
system and prevent any repairing of mutated cells or mutated DNA for the
future of that organism so over a long period of time that increases the
chances that the individual will develop cancerous cells so how do we measure
toxicity like I said before first off we do a lot of animal testing whether this
be good bad indifferent for individuals now realize that animal testing is done
on animals that are bred for the animal testing
so we breed mice we breed rats we breed frogs insects different things for the
testing purpose now I know if you’re you know of certain religions or certain
beliefs that all organisms are are sacred and that no matter what we
shouldn’t be killing organisms for the benefit of anything except for maybe for
you know nutritious benefits to keep another organism alive but for testing
of chemicals and things like that or for scientific testing people have issues
with this problem unfortunately right now this is the method that we use in
the future it will not be the method that we use currently there is a lot of
research in creating synthetic tissues and creating synthetic organs so you’re
just really recreating the genetics and you’re creating the synthetic thing so
no organism actually has to die you just create the synthetic tissue in a petri
dish or in a test tube and then you’re testing the toxicity against that we
have those capabilities we currently do some of that but it’s not to the measure
of the animal testing that’s going on so we have to really be able to create an
entire system and basically create life from nonliving things which is possible
we’ve done it before created life from nonliving cells but
are living cells from nonliving stuff but we’re a little bit off from creating
an entire organism and being able to do this in a laboratory so animal testing
still happens and it’s a concern it really is a humanitarian concern I’m
concerned when I see it and we have thresholds of how many organisms have to
be used and how many organisms can be used so you can so there’s kind of a
maximum number of organisms that should be used and a minimum number so we know
whether or not the testing is legitimate there’s lots of lots of situations like
I said before different individuals are going to have different sensitivities to
different toxins I mean just look at people that you know people that you
know associate with every day you can give them you know a little bit of grass
and some of them are gonna start sneezing and you give another friend you
know a vial with dog hair in and they’ll start sneezing and you know just in the
immune response to these benign things that we have in nature so many people
are sensitivities are very very different
that would also go for toxic things that we’ll see in the environment so for some
things toxicities piece of cake I’ll tell you for animal testing this is a
problem the animals that are used are almost always genetically identical so
there is no diversity of genes and because they’re all bred you know with
the purpose of hey we’re going to use these animals and then they’re going to
be cold off they’re going to die after the experiment so they’re all
genetically identical but that doesn’t no good if we have different
sensitivities from individuals that might be exposed to this chemical and so
that’s that’s a huge problem when it comes to animal testing now there is
complications in measuring toxicity but we often use what we call an ld50 okay
so when we’re doing an animal tests and ld50 means we’re interested in when or
what dosage does 50 percent of the population diet okay so you use a
certain dosage of a toxic chemical and when 50 percent of the animals dies that
is the ld50 okay now the ld50 is not where we hear like alright this is safe
enough for humans okay we don’t want 50% of the humans to die but
we’re after the ld50 so then we can calculate from there wasn’t except
except the bill toxicity right no humans are going to die
that’s an excess acceptable toxicity at least for most chemicals we don’t want
the individuals to die however there are some chemicals that we have out there
that we utilize that we know that the ld50 is you know higher and so it’s it’s
kind of a give and take because the more potent a chemical is so maybe we’re
talking about antibiotics we’re creating a new antibiotic we want that antibiotic
to destroy the bacteria that we’re interested in so we’re looking at an
ld50 of that antibiotic and so the more potent it is though the more bacteria
the faster it will clear someone of a bacterial infection but also the chances
that you might have complications with that and so we’re often interested in
ld50s and again like I said before if this is
done on mice if it’s done on rats if it’s done in frogs insects there’s very
different physiology very different metabolism plus you have those added
effects so an ld50 on a mouse is not an L not the same as an ld50 on a human but
there is no way and we don’t want to see this at least I don’t want to see this I
don’t want to see an ld50 done on humans where 50% of the humans are going to die
you know do that medical test you know most people are not interested in those
kind of tests so in the end measuring toxicity of new chemicals that are
coming out new products new preservatives new food types all these
things can be very difficult to estimate the risk to humans that’s why I said
before often what occurs is produce these products they are
seemingly safe 5 10 15 years later after they’ve degraded we now find out okay
they’re not safe anymore these are awful products and they caused
huge complications once they start combining with other things or once they
start degrading to a certain point so toxicity ratings are based on a certain
you know number of grams per kilogram of body weight and so we we have a certain
toxicity rating and it’s it’s based you know basically it’s just based on you
know if you have a hundred and eighty pound individual we’re going to convert
that to kilograms and then how many grams can that individual have to
produce a lethal dose that’s the toxicity rating that’s where we say okay
this is the lethal dose of this material from there we can classify them in
different ranking modes so very toxic materials is ten percent of that amount
so ten percent of whatever they lethal dose is is a very toxic material
extremely toxic material would require 1% of the amount a super toxic chemical
often it doesn’t even register on a percent it’s a it’s a microgram and you
know very very little of this material is lethal and so we’ll often rank things
based on moderate toxin very toxic extremely toxic super toxic and will
rank them based on those and give kind of a toxicity rain rating that’s based
on you know percentage of you know the lethal dose
all right so acute effects are normally exposed or single exposure and you get
health problems from it so maybe drinking water with lead in it is enough
to cause health exposure and then you only needed to do it one time right
chronic effects are often the result of long-lasting or repeat small dosage of
things you know repeat small dosage of like you know
carcinogens from smoking cigarettes is a good example but a chronic can also be
just one big large dose that’s going to have a lifetime of long-lasting exposure
that that can cause a lifetime of health problems typically acute effects are
immediate health problems you feel it today maybe it lasts a lot a lifetime
but it was due to a single exposure chronic effects could be that you’re
exposed to a large dose and then over your entire life you feel the results
from that or small doses that build up and then eventually cause whatever the
effect might be the problem that we often have is acute effects we know we
know really well because we can take a mouse and we can given an injection of a
certain toxin and we can look at it as immediate health problems boom next
couple 24 hours 48 hours 72 hours whatever it might be but we can see the
exact problem chronic effects though is very very difficult because we can
expose that individual to that chronic dosage or small repeated dosage over and
over and over and over again throughout their entire life and in some
individuals you’ll never see you’ll never see some health problems and in
other individuals it can look like an acute effect like you’ve been exposing
it to a small siege of a certain chemical and then on
day 30 boom now you see this in effect and so it’s hard to decide well is that
a chronic effect was it building up on their tissues or is an acute effect
because they’re now exposed to something else in the environment it’s really
difficult to study these kind of effects the other thing is as we know that as at
least I mean we know this for all organisms but as humans age our cells
deteriorate our DNA gets older so when you know you might have been young and
you might been able to be exposed to UV radiation constantly and never produce a
thymine dimer but now that you’re old and your DNA repair system is old now
all it takes is you know one sunburn and now we produce thymine dimers and now
you know you produce cancerous cells okay and so it’s kind of difficult to
kind of study these chronic effects also you know you can get very different
dosage response occur so like you know you could take these different mice and
we can put them in different groups and you know we might say that the dosage
could be you might get 20% response so you know maybe this is death okay or
maybe it’s a behavioral response you can say right at the beginning any dosage
anything that’s measurable 20% of the population is going to respond to it and
then you’re gonna get you know and up curve from that you know other things
other types of chemicals it doesn’t register at the beginning and it’s it’s
uniform straight up and then there’s other dosages that might not raise your
not register until you hit a certain threshold and then you see that upturn
right so different coke different chemicals different
toxins you know these kind of things can have very different response curves even
if you’re just changing the number of hydrocarbons in something are you just
changing the bonding of certain things whether it has a double bond or a single
bond very simple changes can cause a very different response curve and so for
all chemicals you kind of have to do these different response curves to
figure out well okay what’s the baseline at and you want to use genetically
identical mice in order to do this because you will never get a baseline if
you’re using diverse mites and so over time you know you might have a baseline
that’s down here for one genetic strain and baseline that’s up here for another
genetic strain and on and on now that’s what we really want to know because if
we’re gonna you know supply this to humans that are genetically diverse we
want to know what’s the extreme I mean can you get it could you get a baseline
clear it like 35% lethal versus you know 0% lethal are there is some people that
are exposed to this are they all going to die if they have a certain genetic
disposition or a certain genetic code is it going to cause them you know to
develop cancer if they’re exposed to it even though most my new amount versus
the baseline which most of people the majority of people know I’m gonna do
anything to them okay we’re interested in that but there’s no way to do that
there’s no way to go about calculating those out in a meaningful way so it’s
just not done even though it’s what’s interesting or what we need to know
alright so that brings me to kind of thresholds and what we call the Delaney
clause okay Delaney was a congressman who wanted to put a clause or put a act
together that forbidded any additions of any amount of material that’s known to
be a customer imogen in foods or drugs and so this
started I think in the 60s the Delaney closet might have been a little bit
later in the 70s and you know this was a clause this was passed at first
basically if we know it’s a carcinogen it can’t go into food and drugs well
that’s not possible okay so it’s impossible to meet that standard and it
was replaced in 1996 by non or no reasonable harm
okay requirement so now instead of any amount it’s been replaced with no
reasonable harm okay so less than one cancer for every 1 million people
exposed over a lifetime so the fact that I don’t have one handy but the fact that
people say you know like diet soda causes cancer it can’t I can’t
there is no scientific evidence that suggests that diet soda it causes cancer
now there are other things that it causes it can cause weight gain because
eventually the bacteria in your stomach will break down asperton and use it as a
sugar and so you might at first get this decrease in weight and then next you get
an increase in weight but it cannot be a carcinogen because well first of all
millions of people drink diet soda and we have the stipulation in 1996 it was
put on things one cancer in every 190 people exposed to or a lifetime you
can’t have that okay so if it’s a known carcinogen you can’t sell that you
cannot sell diet soda if it was a known carcinogen so risk and assessment again
a little bit about this risk is the possibility of suffering harm or loss risk assessment is analyzing things
benefit versus risk kind of situation you know a risk assessment a true risk
assessment if a team’s doing this they’re gonna first identify what the
risk is okay and then they’re gonna identify what’s the response or what
kind of response should we have to that risk is this a dosage risk assessment so
how much toxicity is there pollutants or things like that or is it a risk to
bodily harm okay running a chainsaw or something like that and then they’re
gonna say well how many exposures are you going to have are you gonna do this
every single day and then they can classify that risk and certain
classification how risky is this job and so a lot of people will look up like oh
what’s the most dangerous job this is how a risk assessment is done they look
at identifying the risk what’s the dosage if it’s chemically based what’s
the exposure and how do we classify that risk but risk assessments they’re not
really rational I they downplay risk to suit their agenda
okay so interested parties you know let’s say you know companies that really
want people to work for them they will downright downplay the risk of being
exposure I mean how many people who mind for a living know that black lung is a
legitimate concern but they’re their boss will downplay it no matter what
they’re going to downplay how many people are affected by it because you
know they’re the interested party they want you to work for them they’re going
to downplay it now are they going to give you safety of procedures and other
materials and things like that and have you checked and give you limits on how
much time you can expend spend exposed to things absolutely because they don’t
want you to sue them but they’re still going to downplay
we often also tend to tolerate certain risks in depends you know their risk
depends on what we want to do the risk of you know lung cancer for someone that
smokes well it depends do you like to smoke okay if you enjoy smoking and you
know something that you like to do then you’re going to tolerate the risk for
that you know this just depends on lots of things individuals that like to drive
fast they get you know a thrill out of driving vehicles extremely fast
there is a risk behind them with they tolerate that risk even though they know
that driving speeds of 100 miles per hour or more if you wreck the odds are
pretty good that you’re not going to survive that wreck I mean this is this
is often you know the risk assessment and not non rationale between based on
those British assessments the other thing is that most people don’t
understand probability very well so when I say that one out of every two people
every two males is going you know has a potential to get cancer the probability
of you developing cancer is 50% people don’t understand that they don’t
understand probability of injury or risk that’s involved there’s also lots of
things I mean I don’t know how many times people as you know in live
lectures have told me well my grandma smoked for 90 years and never developed
cancer okay that’s a personal experience right that
doesn’t mean that you can smoke for 90 years and not develop cancer you know
it’s a probability still I’m not saying if you smoke or I’m not saying if you
drink alcohol I’m not saying if you you know drive at a hundred miles per hour
you’re going to record you’re gonna die or you’re gonna develop cancer I’m just
giving you the probabilities and that’s where risk assessment falls apart is
because people really don’t want to look at the probability I mean most people
consider themselves above average drivers but this is not
case is not true you’re not an above-average drug I know some people
are above average drivers but you know most people are actually probably
average drivers and quite a few of those that think they’re average they’re
probably below average drivers so often we overestimate things the media over
reports sensitive things we have a irrational fear for some things so for
some things the overestimation is extremely
dangerous I mean for example most people are extremely afraid of rattlesnakes
rattle snakes you know they’re poisonous and venomous oh man they’re gonna attack
you I’m not going to go to a region I’m not going on a hike where there might be
rattlesnakes and rattlesnakes in the United States
maybe maybe kill one person a year maybe I mean you know it’s the risk is there
of course black widows people are deathly afraid of black widows black
widows never killed a human on record never
no one’s ever died from a black widow boy but we we over exaggerate the risk
that is applied with black widows okay does it hurt if you get bit do you have
to go to the hospital you don’t have to you’re gonna lose tissue if you don’t
but yeah there’s risk involved with it but dogs domestic dogs the family dog
kill way more children than a black widow
black widows kill no one way more individuals than a black widow but
literally everyone accepts dogs into their house hardly anyone accepts a
black widow into their house so probability or tolerating probability it
depends on the risk okay so it depends on the individual you know great harm is
accepted only in very low levels of frequency so you know
if if you have a chance to say skydive or you have a chance to bungee jump or
something like that people would normally say well the risk is well what
happens it’s the equipment fall fails okay but if you looked at the
probability of that happening it’s very very low you know people have a fear of
flying the probability of an airplane class crashed again very very low but
because that probability is very very low of that happening we accept great
horror you get an airplane and it crashes not always but you’re
dead okay I mean that’s great harm but the the fact that there’s very low of
frequency that that would ever happen or if you bungee jump and the line breaks
you’re dead great harm but very very low level so a lot of people will accept
that kind of risk okay so for most people a 1 and 100,000
chance of dying is threshold for changing behavior okay for some people
it doesn’t really matter whoops so if we look at something like
the Environmental Protection Agency the risk that environmental or the EPA must
provide is one in 1 million as acceptable for environmental hazards so
we already already told you that ok toxicity level of one note 1 in 1
million is acceptable so 1 in 1 million will develop cancer from this exposure
to this chemical that’s an acceptable EPA regulation look at this ok their
risk of dying from lung cancer if you smoke is one in every four individuals
the risk of being killed by a shark is one in every 264 million people not very
many people when they walk outside and see someone smoking is afraid of that
individual and that individual clearly is not afraid of smoking but many people millions of people are afraid of sharks
okay and if anyone ever said there’s a shark in the water I’m guaranteed you’re
getting out of the water people focus on the lab focus on what they don’t know
alright so when it comes to risk assessment and management again like I
said before when I started this section okay it has to do with your social
economic status of where you act financially it has to do with politicals
and politics behind it has to do with maybe some religion it has to do with
the hazard that you’ve identified so how’s it hazard even been identified the
dosage do you know the dosage okay how much are you being exposed to it and
this will allow you to categorize the risk and take that risk
into account whether you’re going to expose yourself to that or not and you
know some of this stuff other factors can also be you know people chattering
in your ear okay these kind of things are from an
individual basis but it also can be regulatory decisions from EPA and other
things they can be definitely the result of Sociology and who’s the loudest in
the room to get these regulatory decisions applied okay so here real
quick you know these are the lifetime chances of dying in the United States
heart disease is number one cancer stroke motor or motor vehicle accident I
can ensure you sharks are not on the list
flaw floods dog bites bees wasps things lightning strikes I mean you know these
are the odds but you know the top four heart disease cancer stroke and
motorized vehicles okay all right so establishing health policies it’s it’s
difficult there’s so many hazards it out there’s so many risks and humans tend to
avoid risk or you know alter those risks based on situations I mean I know so
many times that you know people would never do something but because their
buddies are around or their friends or their family are around okay they’re
going to do it and they increase that risk because peer pressure
most people know situations where this happens so establishing health policies
around risk can be very very difficult but we do set standards the EPA has
standards and we should always concern ourselves with certain things first of
all combined effects of exposure right this has got to be key we have to know
what happens when you mix certain chemicals we have to know what happens
when the toxicities are mixed between things or after it’s been broken down
that product okay and we don’t have a very good wrap around this okay
different sensitivities I wish we do this different people are sensitive to
different things and we really should know these kind of things and then the
difference between chronic and acute exposure we often don’t consider these
things so we have work to do from the environmental protective agency when it
comes to toxicity and comes to the science and developing those regulations
and these three things are key to that now of course there it’s not reasonable
to say that we’re going to be protected from all contaminants
and there is going to be risk and just living that’s clear it’s but we can
minimize those risks as we develop new products as we develop new medicines new
types of packaging and things like that wait exposing or doing some scientific
research before those products are put out and allowed for the humans that are
not expecting to be part of a research project okay to be exposed to those
materials the other thing that we need to do is we need to look at this from an
eco toxicology point of view and that is we need to really look at what’s the
exposure what’s the risk to the other organisms in the environment we’re often
just concerned about humans and this is really destroyed a lot of ecosystems and
caused a lot of Natural Resources that we once had to be maybe not extinct but
at least to have decreased populations or be not available as a not natural
resource any longer alright so I refer the super long lecture but I wanted to
finish that topic up so we can move on to some other more pertinent topics to
looking at the management of Natural Resources next time