This course covers chemicals in our environment and in our bodies and how they impact our health. It addresses policies and practices related to chemicals, particularly related to how they get into our bodies (exposures), what they do when they get there (toxicology), how we measure them (biomonitoring) and their impact on our health. Most examples are drawn from the US.
Lecture 15: Course Wrap-Up - Resnick and Burke
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Chemicals and Health
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Week 6: Case Studies
At this point you may be wondering: so how do all these pieces fit together? From chemicals in our natural world to production on a large scale, through exposure to health effects and policy . . . this module provides real world examples of how the general public, scientists, industry, governments and non-profit groups come together to effect change. Specifically, we’ll hear about tobacco, contaminated food, drinking water, nanotechnology & worker health. At some point this week (either before, after or in-between listening to the case studies), you’ll need to review, evaluate, and grade at least four of your classmates' submissions from last week. The final lecture offers a summary & conclusion, hopefully providing ideas for next steps for those of you interested in learning or doing more related to chemicals & health. Please let us know how we did and how we can improve!
Rencontrer les enseignants
Dr. Megan Weil Latshaw, PhDCo-Director of the Masters Programs in Environmental Health
Bloomberg School of Public Health
Beth A. Resnick, MPHAssociate Scientist
Health Policy and Management
[MUSIC]
Hello everyone.
This is Beth Resnick and I'm here in the studio with Tom Burke.
>> Hi.
>> We are here to give you the course wrap-up on the Chemicals and
Health course.
So, hope you guys have enjoyed the class so far.
The point of our session today is we really want to try to leave
you with the so what.
Like the main points of what we've been trying to cover over these last few weeks.
And leave you with the key messages of what we hope you can take from the course.
>> So as you know from listening to the previous sessions and
lectures, this is complicated stuff.
Chemicals on the one hand are essential to our bodies, our lives.
On the other hand, they do have health impacts.
So how do we, as a society, manage the risks, protect public health.
And at the same time make sure that we have the things we need for
our everyday life?
So just think about, think of all the ways that chemicals touch you in a,
in a given day.
From that water bottle you're drinking from, as you sit here.
To the disinfectants in that water.
To the personal care products you've used today from your shampoo to other things,
soap and perhaps disinfectants that may be in use.
To the things that your furniture is made of.
So, this course has been really an attempt to put it in perspective.
But to also underscore the importance of
understanding the health impacts of chemical exposures.
>> And I think that would be hard enough to do even if we had all the information.
But the fact that we're doing this with unknown information and so
many uncertainties makes that even harder.
And thinking about balancing the benefits of what the chemicals do for
us versus the potential health effects.
And trying to sort of balance all of that is a huge challenge that we
all face every day.
>> So if you take a look at this slide, and
actually this is, I've done an awful lot of teaching at Hopkins.
But I've never had a lecture that included anything about strippers.
Until this.
So, here is a slide, actually from today's news.
And this could be in the paper on any given day.
EPA identifies health concerns from chemical used in paint strippers.
Now paint strippers, we've probably all used them.
We know that they're an important part of a,
from cleaning graffiti off the sides of buses and subways.
To redoing, like I like to do, old oak furniture and refinishing things.
But we also know that the chemicals that we've used for solvents and
stripping have certain volatile organic components.
That may cause health effects.
And sure enough,
one that is a common chlorinated component of paint strippers was, just today.
As you see in the slide EPA released their assessment of it.
And here's something in very common use, used for cleaning and
stripping and, and getting grease off metals and things like that.
That has health implications for literally hundreds of thousands of workers.
And probably millions of consumers around the world.
On the other hand, there are benefits to having paint strippers, and so
how do we manage these?
This is a tough one.
But this is an example of a regulatory agency,
of a science agency, doing an assessment and putting information out there.
Because I hope one of the key messages about this course has been
the more information we have about health effects.
The more we understand how chemicals move through the environment.
How we're exposed to them.
The better we can do on a societal level and
a personal level because there are concerns about health effects.
>> And a key point here too as Tom said, workers and consumers, so
again that occupational health piece.
I think many of us are thinking about our own personal use,
but that workers are at an even more heightened risk.
In terms of that they are interacting with this on a daily basis in
their employment every day.
>> And it's not necessarily just industry workers.
Probably more than a few of you have wondered as you sat by the copy machine.
Whether things that perhaps are coming off the copy process are exposing you to
harmful chemicals.
So this is a, an issue that it's important to understand.
And it's important to put in perspective.
From a prevention perspective,
it's important to understand how we use chemicals, how we're going to market them.
And how were going to control exposures because of the health issue.
And so, for
the next slide I wanted to actually, bring you back to my own personal past.
To something that was perhaps even today after a long career in
environmental health.
One of the more moving times in my life as a scientist and
as a public health professional.
So here you see a clipping from a New Jersey newspaper.
From August of 78.
A long time ago.
I was a young public health professional and
I was leading the investigation of a cluster of leukemia.
Now you know we've probably talked about the challenge of clusters in this course.
And people's concern, particularly with childhood cancers and
how chemicals in the environment may be related.
One of the more moving things that I've ever done was to
interview the parents of Jimmy.
Jimmy was a young baseball player in the town of Rutherford, New Jersey.
Rutherford, New Jersey, at the New Jersey Meadowlands actually.
Some of you may know where that is.
The Giants play there, the Jets play there.
And they say it's New York, but it's New Jersey.
And the Meadowlands which a lot of people don't know from watching football
was a host to heavy, heavy industry, for the past century.
And so, when there was a number of children in the same school,
the Pierrepont School in Rutherford, New Jersey, diagnosed with Leukemia.
Including poor Jimmy who lost his life.
There was a national concern about chemicals, the environment in New Jersey,
and the illnesses of these young children.
Today, this still remains a mystery.
But we've come along way in really understanding how we might
address some of these challenges, understand exposure and prevent exposures.
Do we know everything about environment and health?
Absolutely not.
Because it's complicated.
It's complicated because many of the influences comes together.
So the epidemiological triad we haven't talked specifically about this, but
we talked about the continuum.
From the hazard to the exposure to the host and to the outcome.
But in epidemiology and something important to understand in
environmental health, is that there are really three major factors.
This triad that affect our health.
There's an agent, so perhaps if you think of a classic case of an infectious agent,
Ebola, Salmonella, Smallpox.
The agent is very important to understand, but you don't have
disease without a host and in many cases you also need the environment.
So perhaps a good example of that agent, host,
environment thing is malaria which is mosquito-borne disease.
We don't have much malaria in the U.S. because our environment has changed.
With screens and
different measures that we've taken to reduce mosquito born disease.
We don't have the suitable environment for the whole triad to come together.
We do have host factors.
We're vulnerable to these kinds of things.
But in many instances, for instance if you've had vaccines against certain
diseases, the host factors can be worked upon to protect things.
And so, I wanted to talk about the epidemiological triad with a focus on
the environment.
Because in this course we learned about chemicals in the environment and health.
And that part of the triad is one where we have a tremendous potential to
reduce disease and reduce adverse effects.
If we can understand, control environmental exposures and
prevent them, we can take a component out of this triad.
And therefore, improve public health.
>> Which is great and we think about all the different policy implications and
types of regulation and the options that we might have.
That would focus in on that environment part of that triad.
And there's a lot of arguments about this Beth, sometimes people say,
well the environment really doesn't cause disease.
So what is it?
Well, actually, somebody once said, maybe it was Beth, I don't know.
All diseases are actually 100% genetics and 100% environment.
Think about that.
That's a good true false question, right?
So think about how important your own genetics are, your own susceptibility.
We talked a lot about that in this course.
Unfortunately some of us are more susceptible to disease than others.
Some of us are more resistant than others.
So, really, the key to a healthy life in a lot of ways is to have
really healthy parents, right?
But, the key to a healthy life is also to live in a healthy environments.
You can have the healthiest parents in the world, but
if you're drinking contaminated water that has pathogens in it.
You're going to have a problem.
So, I think it's important to kind of understand the triad.
Understand that balance of perspectives that genetics is important.
Host factors are important.
And environment is really important.
>> And thanks for giving me credit, Tom.
I don't think that was me saying that.
But the point is, we can argue about the numbers over and over and people do.
But the point is that it's a combination of both as you were saying.
So regardless of what percent it is.
Although people at Hopkins certainly like to think about percentages and
get those numbers right.
The, the bottom line is that, you know, it's all important and
we have to think about it holistically.
You can't only focus on one piece and not the other.
>> And from a personal level.
For instance, my father passed away from lung cancer.
Now, does that mean that I am susceptible?
Well, no, I can control my environment.
He, unfortunately, was, in the early part of his life,
as a soldier, was a heavy smoker.
There are things you can do from a behavioral perspective,
from an environmental perspective, that really change and improve public health.
So, to show just how complicated it is.
And I know we've had a number of diagrams.
And sorry about this, but, but let's get complicated for one slide here.
Think about exposure and
disease, and the various stressors that really contribute to our overall health.
Both as individuals and as communities.
So, how important in genetics, race, ethnicity, well it is really important.
We all know and, and actually I've already had my first cancer right?
I'm an Irish guy with fair skin and a bald head.
And I spent my summers at the Jersey Shore and I got lots of good sunburns.
So I have had a skin cancer already.
Ethnicity part of that?
You bet.
Environment, part of that?
You bet.
All right.
And personal behavior too.
Tom, you knucklehead.
Why didn't you wear hats?
Well I used to have really long cool hair.
>> [LAUGH] >> Now I wear hats believe me.
But location is important too.
Are people in Baltimore people healthier than people in live in more rural areas?
Well it depends.
Perhaps they have more asthma, they have more air pollution exposure.
But they may have less pesticide exposure.
Location matters, not just for value of your home, but
also the quality of your life.
Neighborhood resources,
community stressors, structural factors in your neighborhood.
Is it well lighted?
Do you get fresh air?
Are you near the water?
Is it really densely populated with heavy industry.
There are community level vulnerabilities that the top of this slide talk about,
that combine to give what we call that community stress level.
So we all know that our most high risk communities.
Whether it be for health effects from social diseases or health effects
that are related to poverty, or health effects related to poor environment.
There are community aspects that are important to
prevention that are important too.
So as a community member,
you also have opportunities to safeguard things environmentally.
To make sure your drinking water is tested.
To make sure that there are policies in
your community to reduce exposures to harmful chemicals in the environment.
And then, there's that individual level.
>> So part of this diagram, even though it is so
complicated, I guess depends on how you look at things.
You could get overwhelmed and say there's so
much to do, especially when we look at some of our low resource neighborhoods.
Where they have issues and needs in all of these areas.
On the other hand, you could also think optimistically about how many avenues we
have to really make changes and try to make things better.
And I guess the important piece in these policy debates is sometimes people try to
focus in on only one box.
And not really think holistically about how can we improve our health.
So my sense is,
you can't do these things in a vacuum, you gotta start thinking about all the pieces.
But on the other hand,
you gotta be realistic where there's a feasible opportunity to make change.
And not pigeonhole yourself that if you're not doing everything,
you can't do anything.
So, trying to make sure that you can address these things to
hopefully sort of shift the whole risk that we might face.
>> And I want to point out for
a minute here the purple boxes in this presentation of this slide here.
Of the kind of interaction of environment and health.
And that is, should look familiar throughout the course.
That's that environmental health continuum.
From the hazard itself, the environmental haz, or the chemical.
Now, no adverse effects happen when a chemical exists.
The process begins when there's exposure.
All right, and so we've talked about the continuum.
Exposures are very much mediated impacted by factors in the community.
Are you near a source?
Do you have clean drinking water?
Are you near major smoke stacks and emitters, and things like that?
Or are there factors in your community that would increase your exposure
from poor quality housing to lead painting housing.
To a variety of things that we've talked about in this course as case examples?
So tracking those purple boxes then.
You see, you go from the environmental hazard or the pollutant to exposure.
But then, there's important factor to consider.
That internal dose.
All right?
Exposure itself doesn't necessarily lead to an adverse affect.
Until you reach an internal dose that may be sufficient to cause harm.
So do we have to be concerned about every little molecule of exposure?
Well really, it's that internal dose that biologically effective dose that can
begin to turn the little switches on and off.
Within our cellular systems,
within our receptors in our body, that really begin to make a difference.
And that's when we get below the line into the issues of individual stressors.
That's where who your parents were, your overall state of health,
your state of nutrition.
Those individual factors are so important.
So you can see how this all comes together.
Once we reach that biologically effective dose.
Well that's when we'll begin to see the health effects.
But hopefully we'll be looking at this big picture continuum you can
see how everything kind of comes together.
From a community perspective, from an individual perspective, from
an exposure perspective and a biological perspective to lead to health effects.
The positive side of this slide is think of all the places we
can intervene to reduce risks and have healthy communities.
>> So when we think about it in a framework as to all right,
what do we do about this?
This is a lot of information.
How can we actually process this and think of a way to sort of address these things?
So this slide is really sort of thinking about how do you understand that
chemical risk?
And we've talked a lot about this throughout the course, but
here is our sort of key points, takeaways of what would you do?
So you're starting to think about the chemical in the first place.
So you gotta define do we even have a problem?
What is that problem?
What is the hazard?
And what's the severity of that effect?
So really starting to think about this in a systematic way when you're thinking
about how you might address a chemical.
>> And what is the effect of dose?
The presence of a chemical in the environment does not necessarily mean
that the cascade of harm begins.
But are we at a level of exposure with the population where we
have a dose of concern?
And do we have people in the community.
Who are very vulnerable and susceptible.
You've all heard the warnings when we're going to have a heat wave,
that we reach out to those who are vulnerable.
The elderly, those with preexisting conditions, those who are susceptible.
It's the same for other aspects of environmental health.
We have to understand vulnerability and make sure we protect the susceptibles.
>> And as public health professionals that's really our duty that
the population exposure and the vulnerability and susceptibility.
Because you really need to be thinking about all parts of your population.
Not just a select few.
So as public health professionals, those are the ones that I
think are the key responsibilities and who you need to act on behalf of.
>> Now because we're public health, we love this word prevention.
It's much easier to prevent exposures, to prevent this cascade.
If you understand chemicals from the onset.
If you have sensible management of chemicals.
If you do lifecycle assessment of, what are we going to use this chemical for?
What are the potential toxic effects?
Will we have population exposures related to this?
And do we know how to really dispose of this chemical and
to control its presence in the environment so that we don't create long term hazards.
Prevention is a way of thinking.
And hopefully in this course by understanding the exposure aspects of
chemicals, the toxicity aspect of chemicals.
We can give you some good ideas how we go about managing risks and
working toward prevention.
>> And I think again the point of the whole course.
The more people we can have in the population that understand these
issues and have an education around it.
Regardless of what your job is or wherever you are in the world.
The more people that can really understand this whole continuum.
And can bring some reason to the process of discussing this and
figuring out how we collectively can move forward.
Again, balancing the risks and benefits of the chemicals.
>> So let's wrap this up Beth with the final slide.
First, I know that this sounds a little kind of like a commercial, but Beth?
>> [LAUGH] Chemicals really are essential to our way of life if we wanted to try to
get rid of all chemicals.
That's just not feasible or reality.
>> But understanding the risks are important.
Should we get rid of the really hazardous ones?
Well maybe we need them for certain key things.
And we really can't get rid of every drop of arsenic.
We can't get rid of every drop of certain harmful chemicals.
And we do need things like paint strippers.
We do need things plastics.
Plastic saved our lives.
If you've ever had a surgical procedure or a blood transfusion or anything like this.
Think of all the incredibly positive aspects of chemical compounds,
including pharmaceuticals, that have helped us.
But understanding risk is important, on a societal level and on an individual level.
>> And then this next one, I think, is just so important.
And not just around chemicals, but when we think about public health overall.
Communication is just so key.
It can get really complicated and in these areas where we don't know things.
So making sure that people are sharing information.
So yes, we need to promote more science and better science but
we also need to communicate the science that we already have.
And making sure that we're not talking past each other and
that we're really on the same page.
In terms of how we're explaining what the messages are and what we don't know and
what we do know.
>> That's one thing that frustrates me so
much sometimes, Beth, in our work that there are mixed messages.
That you hear different messages from manufacturers than you
hear from advocates and the scientific community.
And sometimes academic studies give us such conflicting results.
It's really important that we develop better strategies of communication.
But on the individual level, it's also important that people understand the very
many different sources of information.
And be educated consumers of communication to try and
understand what's the bottom line here?
And how might it effect me?
>> Well, and you raise a good point, Tom, and it is frustrating.
That the often times, the mixed messages are actually even from people that are on
the same side of the debate.
You can have scientists contradicting other scientists or
in, one industry saying one thing and another one.
So it's beyond just different sides.
It's just all everybody sort of making sure that we're speaking in
the same language.
And understanding what the other person is saying whether you agree with it or not.
But at least to have a good debate and conversation is the first step.
And being able to come to some type of solution or progress.
>> But I'm going to let you in on a little secret.
Being a great scientist doesn't necessarily mean you're
a great communicator.
>> [LAUGH].
And we really have to get better as academics, as scientists.
To really understand the variety of information and
what the public needs to make good choices.
And how we need to support regulations.
>> And that's what's so important about this course, educating more people.
So that we can all know what the information is that we need, so
we can ask the right questions.
And make sure that we're promoting the right ways to try to
get to that information to get the best answers that we can from what we know.
>> Which brings us to the bottom line for this course.
>> So bottom line is, right, we can't have a totally risk free world.
We know that, but we have to do more and
do our best to be able to manage what we have.
Manage our risks and ultimately, obviously,
we need to safeguard our health in the best way we can.
>> Millions at a time.
[LAUGH] >> So thank you all.
It's been great, I hope you enjoyed the course.
Hopefully, it's just whetted your appetite to learn more and
really start to dig into these issues.
We need smart people addressing these.
And look forward to maybe hopefully having you all get engaged in
these issues, yourself.
>> That'd be great, and I hope to see you in future courses.
Take care.
[MUSIC]
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