Lecture 8B: After 40 Years, a New Toxic Substances Control Act

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Из курса от партнера Johns Hopkins University

Chemicals and Health

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Johns Hopkins University

Chemicals and Health

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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.

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Week 5 - Chemicals Policy: What do we do about chemicals & health?

So far we’ve covered: how chemicals get into our bodies and how we measure them, what our bodies do with them and what they do to our bodies, and how that ultimately impacts our health. Now we turn to policy and how society addresses the impact of chemicals on health. We will hear from a non-profit group that works to change policies such as laws & regulations related to this area. Then we’ll hear how such changes have impacted our health and environment historically, looking specifically at air quality regulation in the US. After you view the lectures in Module 5, there is a second peer-reviewed writing assessment that aims to gauge your shift in understanding the complex relationship between chemicals and health (again grade each other generously).

Lecture 8A: After 40 Years, a New Toxic Substances Control Act4:26

Lecture 8B: After 40 Years, a New Toxic Substances Control Act9:14

Lecture 8C: After 40 Years, a New Toxic Substances Control Act10:00

Lecture 8D: After 40 Years, a New Toxic Substances Control Act11:27

Lecture 8E: After 40 Years, a New Toxic Substances Control Act3:54

Познакомьтесь с преподавателями

Dr. Megan Weil Latshaw, PhD
Co-Director of the Masters Programs in Environmental Health
Bloomberg School of Public Health
Beth A. Resnick, MPH
Associate Scientist
Health Policy and Management

So I want to step back a little bit for a few moments and

describe some of the drivers that led to this final reform of TSCA after 40 years.

What caused it to get onto the national agenda and actually cause Congress to act?

Well, the first thing is simply the fact that chemicals are everywhere.

And increasingly, there are questions being raised about their safety.

About 10 trillion pounds of chemicals are produced every year in the US.

And you can imagine wearing a 90-pound backpack on your back.

And then at the end of the day putting that one aside and

the next morning picking up another one.

That is literally how much in the form of chemicals that are regulated under TSCA,

we produce and use every day.

They're used to make just about everything around us.

96% is an estimate.

That excludes a few things like wood and other natural materials.

But just about everything we touch and

use is made of synthetic chemicals regulated by TSCA.

Now, we don't actually know how many chemicals are in US Congress but

we have some ball park figures.

We know that 85,000 chemicals have been in Congress

at some point since TSCA originally passed in 1976.

We know that not all of those are in commerce today but

we don't know how many actually are.

In fact when TSCA passed in 1976 there were about 62,000 chemicals on the market.

And those were put on to what is called the TSCA Inventory.

And then 23,000 new chemicals were added.

At a rate of between 500 and 1,000 a year.

So there really are a lot of new chemicals coming in the market,

replacing old ones, and some of the old ones simply are no longer being used.

So, we'll get to how TSCA reform

deals with getting a better handle on that in a moment.

Some of the reasons why TSCA reform suddenly became a priority for

the Congress, is because of a series of findings and scientific research,

that began to connect the dots between our use of chemicals and

diseases that are on the rise in the human population.

We know that certain diseases such as certain childhood cancers,

infertility, asthma,

reproductive effects are all on the rise, and they're on the rise in manner

that really can only be explained as a result of environmental factors.

And, increasingly,

there's evidence that chemical exposures are one of those factors.

We know that because in laboratory studies, and

sometimes even in human epidemiological studies, certain chemicals have

been linked to the same diseases that are on the rise in the human population.

And finally,

we now know that many of those same chemicals actually are in our bodies.

We have been exposed to them through the products we use, through the food, and

air and water that we consume.

Those chemicals can be found now in our blood.

Some of the diseases that I mentioned before that have been linked in

scientific studies to direct chemical exposures, include this really long list.

Many of the major chronic effects in humans that we worry about and

that we are doing a lot to try to reduce, chemicals have a role.

It's often hard to quantify, some chemicals have a very strong link,

other ones less clear.

However, increasingly there's a worry that the use and widespread

nature of chemical exposures is resulting in health effects in the human population.

We know that, in part, because we better understand how chemicals

get from where they're being used, or made, to our bodies.

We know now that chemicals can be transported very long distances.

For example, the arctic regions of the world actually

have some of the highest concentrations of certain synthetic chemicals.

And they got there, not because people are using products containing them but

because those chemicals were released to the environment and

then transported long distances through the air or the water.

And also through the contamination of wildlife that

moves long distances as well.

So marine mammals in the Arctic have some of the highest concentrations of

certain synthetic chemicals found on Earth.

We know that chemicals can get out of products that they're used in and

into the environment and into people.

And let me just mention two brief examples.

If you go out on a parking lot and you look at the surface of that,

it's often sealed with a very dark or black coating.

That is intended to keep rain water out and make that driveway last longer.

Well it turns out that those sealants contain chemicals and

those chemicals don't just stay put.

They actually run off into water during rain events.

And they are actually now known to be picked up by one's shoes,

when you walk across a parking lot or your driveway, and they are brought into your

house and end up as a contaminant in the dust in your house.

And this has now been scientifically shown by researchers at the US Geological Survey

to be a significant source of exposure to some very dangerous chemicals,

chemicals we know cause cancer in people.

The other example are so-called brominated flame retardants that have been used for

a number of decades in the furniture that we sit on, in the upholstered furniture.

And it's specifically put into the foam as an effort to try to

reduce the fire risk, should that furniture catch on fire.

What we now know however is they don't just sit in that foam.

They actually are emitted or released from the foam over time.

Every time you sit on it and

compress it, a little bit of dust comes out through the upholstery.

And that dust is laden with these brominated flame retardants.

And we know from animal studies and sometimes now human studies that some of

those chemicals can adversely affect our health.

We also know that we're not all exposed to chemicals at the same level or

in the same way.

In fact, some people are more exposed than others because of where they live,

what kinds of products they buy and can afford to buy.

And other factors like that, that are differential across the population.

And this is part of a much broader set of issues

that goes under the words environmental justice.

Because some people who live in poor neighborhoods,

in sub-standard housing, less access to healthcare and

the like, may also suffer from disproportionate exposures

to chemicals from the environment and even from products that they use.

We know some of this because of advances in science,

that include the ability to actually monitor human beings for

the presence of chemicals in our bodies.

And this is a called biomonitoring and

the advent of that really goes back a couple of decades.

But the more chemicals that we have looked at and we do so through

a government program that looks at several thousand people every couple of years.

The more chemicals we look for, the more we find.

And we know that some of those chemicals are in fact toxic.

So that is another connecting of the dots here, that those chemicals that are in

use, that are linked to diseases are actually being found in our bodies.

And finally,

there's a large body of evidence that suggests that probably the most

vulnerable period of time to be exposed to chemicals is during very early life.

In utero, a pregnant woman who's exposed to chemicals can pass some of those

chemicals through the placenta to her developing fetus.

And in early infancy, when children's metabolism is changing,

when many of its systems are being developed,

its neurodevelopmental system, its immune system, and so forth.

Chemical exposures during that window of vulnerability

can be particularly troubling.

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