10. Safe Drinking Water: Science and Law

10. Safe Drinking Water: Science and Law


Prof: Today I want to
talk about water and the law that surrounds drinking water,
to talk about its quality, talk about what your rights are
to clean water. To also give you a sense of
what key threats are to drinking water,
what your exposure might be, and what we might do about it
both legally but also personally.
Water is a critical component
of our environment and our bodies.
Your body is close to seventy
percent water. You can go for several weeks,
two to three on average, without food.
You can only go for about four
minutes without air. And you can go for maybe four
or five days without water before you die.
So water is absolutely critical.
And one of the key arguments I
want to make today is that it’s a largely neglected area of
environmental law, given the rapid increase in our
knowledge about chemical threats to water quality and where those
threats come from. So what are the major
challenges in water on a global scale?
Clearly one is water-borne
diseases. Diarrheal diseases are
recognized to kill between four and five million people per year
in Africa. Aquifers that cross property
and jurisdictional boundaries are a critical issue.
So many rivers form the
boundary between nations or between states.
The Connecticut River is a very
good example, separating Vermont from New
Hampshire. Point source control versus
surface runoff. We’ve had a long history in the
last half of the twentieth century of trying to control
point sources or pipe releases to water supplies,
as opposed to thinking about how chemicals may accumulate on
the surface and then be washed into rivers that are used for
drinking water sources following serious rain events.
Ground water depletion,
the Ogallala Aquifer in the Southwestern part of the United
States and in the western part of Texas,
is being rapidly depleted. And its contamination is well
recognized. Aquifers around the nation and
most industrialized countries are now more intensively tested
than they had been before. And it’s recognized that they
contain chemicals that never were anticipated to persist or
to migrate. Private wells.
The Safe Drinking Water Act has
been established in the United States to require testing and
control the chemical content only in water systems that
supply more than fifteen households,
fifteen or more households. So if you grew up perhaps in a
rural part of the nation or you live outside of New Haven,
you may have your own well, as I do.
So I have a 600-foot-deep well.
And when I purchased my house,
I was quite happy with that prospect,
thinking that water on the surface would need to be
filtered down through the soil before it got down into the
well. And it was quite striking,
I had quite a lesson from a well driller.
My well went dry one day,
I didn’t know what happened. So I called the well driller
and he came out and it was a pretty remarkable lesson for me.
Within forty-five minutes,
he had pulled up the well head, he had coiled the water,
coiled the pipe, and I recognized that I hadn’t
paid any attention to the fact that the casing that surrounds
the well could convey water that had been contaminated on the
surface down the side of the casing and into the underlying
water supply. I’ll tell you more about the
plastics side of that story in a few weeks.
So wells that service greater
than fifteen households are regulated under the Safe
Drinking Water Act, which means that if a chemical
is listed on the EPA’s list, then community supplies have to
test for the presence of that chemical.
And if a maximum contaminant
level has been set, that means that the provider
has to demonstrate that that ceiling has not been breached,
or he or she would have to install some sort of filtration
system. So within Connecticut,
by the way, that means that approximately thirty to forty
percent of the Connecticut population is getting water that
is not managed in any way by the Safe Drinking Water Act.
Surface water in the United
States is generally believed now to be undrinkable for a variety
of reasons, mostly because of biological
contamination, the threat of E.
coli, but also giardia,
which is carried by both humans and by animals in their wastes.
Monitoring and surveillance
needs much improvement. I’ll talk more about the
monitoring system that is currently in place and why it’s
deficient. Public water infrastructure
also is inadequate. How many of you know the way
that water moves from its source to your tap?
What kind of equipment does it
go through? What kind of filtration does it
go through? What kind of land uses are
allowed in the watershed that surrounds the lakes that provide
New Haven’s water supply? And what about the pipes that
convey the water to wherever your tap is?
Do you know what they’re made
out of? Are they plastic?
Are they copper?
Are they bronze?
Are they metal?
Are they leaded?
There are many connectors in
many cities that are quite old that are no longer allowed to be
installed that connect the water main itself into your apartment
or into your house. But they exist and remain
because it’s extremely expensive to dig up every connector and
replace it with one that does not contain lead.
How about your faucet itself?
What’s your faucet made out of?
Well, many faucets are made out
of brass. And increasingly,
they’re made out of plastic, plastic that is painted to look
like it’s metal, painted silver.
You have to be really careful
when you buy a faucet system or you put in a drinking water
supply system to really think deeply about the source of the
materials and their leachability into your supply.
The leachability is driven by a
variety of factors. It could be heat.
So for example,
you certainly would not want to make a cup of tea by turning
your hot water tap on and then putting a tea bag in the water.
Or you want to feed infant
formula to a small child by putting powder,
for example, in a glass, and then filling it
up with hot tap water, because the hot tap water is
likely to leach more compounds from the pipe or whatever the
conveyance system is than cold water would.
How long do you wait to let the
water run before you take a drink out of your tap?
Makes sense not to drink water
that has been sitting in your tap overnight or you come back
from vacation for a couple weeks.
We now recognize that water
that sits in pipes takes up contaminates from the conveyance
system. So all of these issues are
worth thinking about in terms of infrastructure.
How about water rights?
Really, what are your rights to
clean water? And the core question of this
lecture is really how safe is safe enough?
And how do we define safe,
particularly using the language of the Safe Drinking Water Act?
And finally,
how does land use affect water supply?
So many people are not at all
thoughtful about where watershed boundaries in the vicinity of
where they live. They’re not thoughtful about
how chemicals can migrate long distances.
I worked in California in the
Central Valley near Fresno for a while on a project where
chemicals were recognized to migrate more than five miles
from their point of application to an agricultural field into
underlying aquifers. So it depends very much on the
underlying surficial geology, the soil structure,
the bedrock, the groundwater regime,
how fast a chemical will move. Some move really quite quickly,
others move really quite slowly if they can bind to organic
matter. So once again,
the Safe Drinking Water Act covers supplies that have more
than fourteen connections or more than twenty-four
individuals. There are 53,000 water systems
in the United States, and 43,000 of those rely on
groundwater and about 10,000 rely on surface water.
And they’re roughly split
fifty-fifty, public and private. And there are 15 million wells
in the United States that serve individual residences,
and roughly 45 million people, maybe fifteen percent of the
population in the nation are drinking water that is
completely unregulated by the Safe Drinking Water Act.
I wondered about this and I
wondered about what we could find out about well water
vulnerability. And also if a casing surround a
well is cracked, that means that chemicals
applied to the surface have a higher chance of migrating down
the inside of the casing. So I asked the Department of
Environmental Protection and the Department of Health here in
Connecticut if I could get a hold of their database–
GIS, Geographic Information System that they had that
identified the location of all wells in Connecticut,
all wells that had been mapped and geo-coded.
And then I overlaid that data
with surficial geology. And then I started looking at
old air photos, wondering about former land
uses. And a pattern started to emerge
that in many areas that had been former agricultural lands,
these had been developed into residential areas and wells had
been dug into those areas and provided unregulated water
supplies to almost a million people in the state of
Connecticut. It’s kind of an interesting
story. When I asked for that database,
I was denied access to it. This was post-9/11,
because they were worried about releasing the geo-coded data on
precisely where the wells where. So I had to sign a paper that
promised that I would be legally responsible for securing that
data and maintaining its confidentiality and I would not
release it to anybody who could do something nasty to a public
water supply. So what about compliance?
How are we doing in the area of
compliance? Well, 30 million people drink
water each year. A little hiccup there for some
reason. Thirty million people drink
water each year from systems that report violations of
health-based standards. There are about ninety-three
chemicals that are not now on the Safe Drinking Water list,
that have maximum contaminant levels assigned to them.
So 30 million people,
ten percent of the population, drinking water that the systems
have reported are in violation. Ten thousand systems violated
health-based drinking water standards and about eighty
percent of the public water systems have reported no
violations. And EPA has issued 86,000
violations of federal requirements to monitor or to
report results. So the overwhelming number of
violations are associated with the failure to monitor and the
failure to report. So if you don’t look,
if you don’t monitor, you can’t find a problem.
And if you find a problem and
you’re a municipal supplier, that’s going to cost a lot of
money. You’re either going to try to
pass that cost back on to consumers as increased prices
per gallon for their water. But certainly,
you’re not going to want to–there’s commonly a delay in
reporting. So what is an MCLG?
A maximum contaminate level
goal? EPA established both the
maximum contaminant level, which is a legally enforceable
limit. But they also established a
maximum contaminant level goal, which is a health-based
ceiling. So you would hope that the
legal limit would be the same as the health-based limit.
But that’s really not the case.
So the Safe Drinking Water Act
creates the contaminate level limit as the highest
concentration of a contaminant that’s allowed.
And it also allows a
cost-benefit analysis that’s required under the Safe Drinking
Water Act to consider what the cost would be of meeting that
limit. If the cost is found to be
excessively high, they’ll set a goal that would
be higher to protect human health,
and allow a contamination level to be higher than that.
So here’s a chart that gets us
to really what our present level of regulation is.
And you see that after the Safe
Drinking Water Act was passed back in 1976 that no new
standards were enacted. It’s been kind of interesting.
So Congress basically gives EPA
the mandate to regulate and monitor water supplies,
but EPA doesn’t really do very much about it.
This period in the 1970s and
early 1980s was a period that EPA was concentrating on source
emissions from smokestacks as well as auto emissions and also
a variety of pesticides. But really, it was paying very
little attention to drinking water.
So it added seven volatile
organic compounds in 1987, about eleven years later.
Copper and lead were not
revised based upon new evidence of their toxicity from data that
had been collected back in the 1970s until 1991.
So remember,
I argued earlier that there’s often this delay between
recognizing that a compound is more hazardous than earlier
thought before the agency would take action and set a new limit.
We’re seeing the same thing
play out here. Well, Congress was upset at
this delay and they demanded that a variety of new chemicals
be added, including thirty-nine
pesticides, volatile organic compounds,
metals. So these were added in 1991.
And then during the period of
the 1990s, seven years, there were no new standards.
Well that’s kind of
interesting, because you might assume quickly that in a more
liberal administration that you’d have more rapid listing
chemicals, you’d have a more protective
character. This is not the case.
So that the liberalism or the
conservatism of the administration seemed to have
little influence on this rate of adoption.
So today we’re sitting here
with about ninety-three different chemicals.
And just to give you a sense of
how limited coverage and limited the protection level is,
think about this. That among the thirty-nine
pesticides that are monitored and have these maximum
contaminant limits, there are approximately 1,000
more that are completely neglected.
Nobody’s testing for them,
but they’re allowed to be used on agricultural crops.
And many of these have not been
fully studied to know how they move through different kinds of
ecosystems or different kinds of geologic systems and what their
potential is to contaminate the water supply.
Think also that more than 800
other chemicals, including industrial chemicals,
have been detected in water supplies by the U.S.
Geological Service.
And by the way, the U.S.
Geological Service is playing a
really unusual role in this regulatory process in that they
sit within the Department of the Interior.
They’re completely unrelated to
the Environmental Protection Agency.
But they’re playing a more
vigilant role in monitoring chemical content and hazards in
underlying aquifers, as well as surface waters,
than the Environmental Protection Agency had during
this period of time. So this is a history of
neglect, of limited surveillance,
and it’s being driven by one fundamental characteristic of
this statute. This is a listing statute,
which means that every time a new chemical is discovered and
EPA decides they hope to either set a goal or to set a limit,
they’re going to get a fight from all the municipal suppliers
or the private suppliers because the testing costs are going to
be passed on to them. And these testing costs are
often not minor. By the way, it’s interesting to
think about what the effect might be of establishing a new
chemical limit. Well, it may mean that you need
to conduct a brand new type of test.
It may also mean that you need
to install filtration equipment, perhaps activated carbon
filtration, which is extraordinarily expensive.
And the smaller the water
system is, the more expense it’s going to allocate per individual
household. So if New York City,
for example, is facing a new standard that
EPA has adopted, they can pass the cost of
monitoring and filtration on to a very broad group of people.
But if you have a much smaller
community, say in the rural west of a
couple hundred people in an isolated area,
that’s going to be much more difficult for them to comply.
So there’s been a trend towards
source protection instead of consumer protection.
And in part,
you can see this happening, what the public response to
this has been, which is to rely increasingly
on bottled water. And many people have the
perception that bottled water is much safer than tap water is.
Well, it’s not at all clear
that that is the case. Many people do not understand
the filtration techniques of bottled water companies.
We don’t really have clear
standards. And also, many of the companies
that are marketing heavily in the United States are now
foreign companies. So the public’s perception of
safety is really poorly founded in scientific evidence.
Also, there’s a story about
plastic. What about the potential of
plastic ingredients to migrate into water supplies?
I’ll give you one example.
About fifteen years ago,
I had bottled water in my house as we were putting in a new
water supply system. And so the bottled water came
in a jug that was polycarbonate, a five-gallon jug.
You probably have all seen
these, that you’d flip upside down.
And I had left that bottle
outdoors, actually had been away for the weekend,
it was delivered on a Friday during the summer months.
And the temperature had gone up
to about 102. And it was sitting on my
driveway in the sun when the ambient temperature was 102.
So it was really baking.
So when I opened the bottle and
put it on the stand, I found that it had a really
very acrid taste to it, a bitter, acrid taste.
So I called the water company
and I asked the bottling company what might that be?
And the response was,
“Oh, we’ll have a new shipment out to you right away.
It was probably just the
cleaning agent or the disinfecting agent that we put
the bottles through.” Well, I studied the problem
more intensely and found that they were using a disinfectant
that was actually a registered pesticide.
And also this was perfectly
allowable because it makes sense to try to disinfect water
bottles that are coming back that may have had stagnant water
within them. But somehow,
the rinsing process hadn’t effectively removed the cleaning
agent. Well, the bottled water problem
goes on in that I looked more carefully at the potential of
plastics to migrate from the polycarbonate into water.
And heat, solvents such as some
biocides are mixed with, also cracks in the bottles
themselves can cause the chemicals to migrate more
frequently. The offending chemical in this
case is bisphenol A, and we’ll talk more about that
later. If you look across the maximum
contaminant limits and you compare them to the public
health goal, this study by the state of
California found that the maximum contaminant limit,
the allowable concentration, was often two,
four, even sixteen times higher than the health goal,
which tells us that in many cases the agency is making a
determination that we can be exposed at a limit that they
believe is not health protective.
There are other studies that
have demonstrated a similar finding for other chemicals
besides the elements. So one of the ways to think
about the effectiveness of any statute is to think carefully
about how it’s monitored. So what sampling design should
be created in order to figure out whether or not we’re
effectively searching for chemicals that pose the greatest
threat? Well, I asked this question of
the New Haven Water Authority and found to my surprise that
systems of twenty-five to a thousand people are only
required to provide one sample per month.
And it’s pretty clear that
there are certain climatological events,
like very serious rain storms, that can wash contaminants off
of surfaces, whether it’s an agricultural
field or say a large shopping center parking lot,
into surrounding water supplies if they are nearby.
So thinking about the
importance of the sampling period is really critical.
And if recent reports have
demonstrated compliance with certain standards,
then EPA allows the testing to be limited to only four times
per year. And for some types of systems,
such as New Haven Water Company,
they have not found certain pesticides,
so they’re allowed to monitor only on an annual basis.
They can appeal to the
Environmental Protection Agency to reduce the periodicity of
their sampling. And this of course is very
important to them, because it saves them a lot of
money. Trizine herbicides provide a
really good example of this in the Midwest.
So trizine herbicides,
they’re known as pre-emergent herbicides.
And they’re commonly sprayed on
fields such as cornfields. And they’re sprayed during the
spring. And the spring in the
midwestern part of the United States is kind of famous for the
intensity of its rainstorms. So the sampling design relative
to the rain events really proved to be extremely important to the
findings. You can pay more attention to
the slide online, but these data demonstrate the
ways that increasing the stringency of standards passes
costs on to water supply companies and to people that are
served in really an inequitable way that is dependent upon the
size of the public water system. So I want to concentrate today
and tell you a story about this chemical.
This is a trizine herbicide and
now it’s about twenty-seven-year-old story.
But atrazine has become
infamous as one of the most heavily used herbicides in the
world. Its uses in the United States
include food crops: field corn, sweet corn,
sugar cane, sorghum, winter wheat,
guava, macadamia nuts. It’s used also on nonfood
crops, such as hay, pasturelands.
It’s also used in forestry.
It’s also used in residential
and industrial and recreational areas.
On residential turf,
within parks and on institutional turf.
Also on golf courses.
And it’s used for landscape
maintenance. And the whole idea behind an
herbicide is to kill other species of plants so that they
don’t rob nutrients away from the desired or highly valued
plant. So it’s also sprayed on
roadways. And this is an interesting idea.
It would be a great student
project. Think about the number of miles
of roadways in the United States that are treated with
herbicides. My town is a good example,
little town of Killingworth. They don’t like to cut the
vegetation next to the guardrails.
So what do they do instead?
They come along with a truck
and they just spray the side of the road.
Next time you get on Amtrak,
take a look at the vegetation that goes along the track,
and you’ll see almost nothing. You’ll see it devoid of
vegetation. How do they do that?
Is it just that they didn’t
plant anything? No.
Because seeds would blow into
the area and they would grow unless chemicals were applied.
So along major highways in the
United States, along state highways in many
communities in areas that have guardrails,
along corridors that are used for power lines or rail on the
runways of many airports, pesticides are applied.
So if you count up the total
area in the nation where these herbicides are applied,
you can quickly get up to hundreds of millions of acres of
the landscape. It’s really quite striking.
So, you know,
finding a chemical such as this in the water supply really
should not be that much of a surprise.
But no one has really looked
systematically at where concentrations of applications
are going on. But I’ll give you one example
of where you might conduct this kind of a study.
And that’s with golf courses.
So that about $225 million per
year in the United States are spent on chemical treatments of
golf courses. There is almost no landscape
that I could imagine, including agricultural lands,
that are treated more intensely than golf courses,
and particularly putting surfaces.
So about $1,300 per acre of
35,000 acres of putting surfaces are receiving quite a variety of
different biocidal compounds. As a nation,
we need to think about where are we applying chemicals the
most. And we’re doing it
predominantly to field crops: field corn–
about 59 million acres of field corn is treated,
sorghum, sugar cane, sweet corn–in both processed
and fresh form. So large percentages of these
crops are treated with atrazine. So if you map out the
concentration of atrazine in streams in the United States,
you see it centered on the Midwestern part of the country,
and this is the primary corn-growing region.
So what you find is
concentrations in the microgram per liter level,
which is a part per billion level.
And the maximum concentration
level, the MCL for atrazine is, I believe it’s three or point
three. Excuse me, parts per billion.
And if you look across the
nation to the number of people now that the Environmental
Protection Agency think are drinking residues of this
chemical in the water supply, you see this adds up to
millions of people. So large circles,
like the one around Texas, represent more than 8 million
people. Circles around Florida
represent about 4 million people.
So you see that they’re finding
it in the water where it’s most heavily used for agricultural
purposes. So this was first registered in
1958. And by registered I mean it was
given a license, it’s like a driver’s license.
So atrazine,
it’s regulated under the Safe Drinking Water Act,
it’s regulated under the Clean Water Act as well,
and EPA began a Special Review that reserve for chemicals that
they have particular concerns about in 1994.
Now Special Review has had a
rather infamous history inside EPA.
And I have a good friend who
graduated from Yale who has worked her way up to a high
level inside the agency. And she refers to EPA’s parking
lot. And the parking lot is a place
where EPA stores chemicals, not literally,
but figuratively, when it decides it’s not going
to take any regulatory action on them.
So atrazine was put in the
parking lot, so to speak,
receiving little attention for much of the 1980s,
when these data came out, when people realized that the
concentrations were going up. When the parking lot fills up
with additional chemicals, it basically means that the
chemicals take longer and longer to receive review,
and you have a lower and lower probability that health-based
standards are going to be set in response to new evidence of
serious contamination or risk. Another problem with atrazine
is that it’s structurally so similar to other kinds of
herbicides, including simazine and propazine.
And it produces similar
chlorinated metabolites. Metabolites are byproducts that
the compound, the original compound,
breaks into. That it makes sense to think
about how we might be exposed to clusters of these compounds,
instead of treating them individually.
So remember my argument earlier
that EPA’s attention is focused chemical at a time.
So they’ll make a decision on
atrazine without thinking about simazine or propazine.
But in terms of your exposure,
in terms of its behavior inside your body,
there is a presumption that chemicals that are so similar in
structure will behave similarly in your body and pose a similar
threat. So as a society,
we want the government to pay attention to these mixtures,
particularly if there’s a plausible reason that we might
be exposed to the mixtures. So in 1991, the MCL was set at
three parts per billion. And the MCLG was set at three
parts per billion as well. And the compliance was
determined based upon a running annual average,
with quarterly samples required by EPA or a single average
sample. Also in the late 1980s,
this was classified as a possible human carcinogen.
But then the Environmental
Protection Agency reviewed it as not a likely human carcinogen.
Now, how do they make these
choices? Well, they submit evidence to
what they call a scientific advisory panel.
And I’ve had the experience of
sitting on EPA scientific advisory panels for nearly a
decade and reviewing new evidence of risk.
And the decision on the part of
the panel to recommend a classification as a carcinogen
or not a carcinogen or a chemical of high concern or low
concern, it really depends very much
upon who is asked to sit on the scientific advisory panel.
And I want to recommend to you
the work of a professor at Harvard, Sheila Jasanoff.
Sheila came here as a visiting
professor for a while. And her work has been very
important on what she calls the fifth branch of government,
which are these advisory panels.
So evidence is often so complex
that an agency is not really clear what they’re going to do.
Is the risk higher?
Is it lower?
Should we regulate?
Should we just warn people?
How are we going to manage this
chemical? They’ll submit this question to
a scientific advisory panel to gain their advice.
Well, the political makeup of
these panels makes a terrific difference in guiding the
ultimate outcome. So the Food and Drug
Administration, the Occupational Safety and
Health Administration, EPA, most regulatory agencies
rely very heavily on these scientific advisory panels.
But just because a scientific
advisory panel makes a recommendation,
doesn’t mean that you ought to believe it.
Prior regulation,
they looked at the chemical more intensely and they found
that prior regulation was insufficient.
So that they deleted rangeland
millet in pineapple uses. So instead of prohibiting the
chemical outright, they would look at the
particular uses, probably uses that did not have
a very high economic value, and decided to go after those
to prohibit or further restrict those.
They also used what they called
a restricted-use classification. And pesticide law,
FIFRA, the acronym Federal Insecticide, Fungicide,
and Rodenticide Act, it has this restricted-use
classification. And this is an interesting idea.
I was telling a section last
night that it’s similar to the idea of a pharmacist.
In other words,
in the world of pharmaceuticals,
we had this intervening layer of expertise so that the
pharmacist plays a role of interpreting exactly what the
appropriate dose is for you. So the physician doesn’t give
you the drug directly normally. Although this happens in a
hospital often. But in a pharmacy,
you get access to a chemical that poses certain risks because
experts are there behind the counter to make sure that you’re
getting the proper dose and that you understand that there could
be drug interactions or that there may be certain side
effects that you should be aware of.
So this same concept was built
into pesticide law, but in a very different way of
training licensed applicators. So if a chemical is classified
as being restricted use because it is more toxic or it’s more
persistent or it poses a certain kind of a health threat,
then someone has to be trained before they’re allowed legally
to apply it. And within the pesticide
regulations there is a provision so that supposing I went and I
got my license. So I was licensed to apply
dangerous pesticides, particularly in,
say, restricted areas that were ecologically vulnerable or maybe
inside schools or hospitals. So that I have the legal
authority to delegate that responsibility to you.
And if you have no training at
all, makes no difference. And I would tell you what to
do, I would tell you to follow the label directions very
carefully. But remember what I was saying
about literacy and background literacy.
So how do you mix say a quarter
ounce of a toxic substance in, say water or in kerosene or
some other solvent that it’s supposed to be sprayed in?
And how do you know that you’ve
got exactly the right concentration?
Well, it takes some
mathematical skill to do that. And I’ve run across a couple of
cases that I was describing last evening where people that were
delegated this authority not only had a minimum level of
literacy, but also had virtually no
mathematical capacity to make these kinds of judgments.
So EPA realized this eventually
and they started requiring containers that were in a sense
foolproof, so that you would tip it,
they call it a tip-and-pour mechanism.
So you could pour out only the
correct proportion of the active ingredient.
And then all you had to figure
out was whether or not you had to add one or two gallons to it.
So this reduced the error rate.
But if you are spraying a
pesticide, as an example,
and you’ve got a backpack on and you’ve got a spray wand,
I mean, I could be spraying the edge of this podium and walking
along. My cell phone could ring.
I could stop.
I could look at my watch,
and then I could move on. And the effect would be what?
Well, when I looked at my
watch, wherever the wand was pointing,
it would get a dose that probably would be dozens of
times higher than if I were walking in a uniform way.
There’s kind of an interesting
analog to that with respect to spray planes or tractors.
So you can imagine a tractor
that has a bar across the back end with holes on it,
such as it’s going to irrigate a field.
Well, the truck goes along,
gets to the end of the field. It turns around,
comes back this way. And eventually,
it covers the entire field. Well, if it has the same
application rate, the same emission rate from the
pipe regardless of the speed of the truck,
where in the field are you going to get the higher
concentrations? At the ends of the field,
where the truck slows to turn around.
Similarly, if you can think
about spray plane coming in and spraying the hypothetical field,
which is the platform up here. They pass this way,
then they come back and they pass another way.
I’ve seen farm workers in
California standing there with just shorts and a straw hat on
kind of waving as a marker for the spray plane,
being sprayed repeatedly. There’s an occupational side to
pesticide control that I don’t have time to express to you.
But then you get this overlap
of the spray in the field. So these kinds of practical
conditions have a really important implication for how
you set up your sampling design. So if you sampled in the middle
of the field that was treated by the truck,
or the tractor, you’re going to get a lower
level of concentration than if you sampled at the end of the
field. The same may be the case with
respect to spray planes and the way that they spray fields.
So the dance of regulation is
one where the government will say,
“Look, we’ve got to cut back your use,
we have to protect the water or we want to reduce worker
exposure.” And the industry that
manufactures it will say, “Well, you know what?
Don’t cut back in this area,
cut back and restrict its use on a specific commodity,”
probably one that is not an economically productive one for
them, or particular kind of use.
So the argument about what uses
are restricted as opposed to which ones are prohibited gets
quite technical quite quickly. So if a chemical comes back as
a recognized, serious threat to human health,
that doesn’t mean it’s going to be prohibited.
Prohibition is very unlikely.
I mean, there have been so few
bans in environmental history, probably fewer than 300 bans,
outright bans of chemicals. I’ve talked to you about a
couple of them, DDT is a good example.
And aldrin and chlordane,
these are all pesticides. But for the vast majority of
compounds, instead, you get this minor
revision in the way the chemical is allowed to be mixed or
applied, it’s put into the
restricted-use category. It’s allowed to be used on corn
but not on other crops, so that the market share can be
maintained. Here’s a graph of the seasonal
pulse of atrazine in water supplies that was recognized in
the Midwestern part of the United States.
You can’t see the years here,
but this is 1995,1996, 1997,1998.
And you see this pulse.
Because they apply it in the
spring and then the rains will wash it into the surrounding
water supplies. Well, so another sampling
design issue here that really is critical to the effectiveness of
the statute is that if you decided that you were going to
sample say in September of each year,
you’re going to miss this pulse. So it’s only by sitting down
and thinking about the method of application,
the timing of the application, and thinking about it in a more
systems or ecological manner that considers climate,
that you would be able to pick this up.
There was a very legal debate
as well about what this chemical is doing, where it’s moving.
And the U.S.
Geological Service found that
it travels actually hundreds of miles from its site of
application. So it’s running off the fields,
it’s getting into streams, and it’s getting into rivers,
such as the Mississippi River, and it’s moving long distances.
So this study found that some
states were receiving fifty percent of their pollution load
from out of state. So if atrazine is reaching say,
Louisiana but we know that it’s not applied in Louisiana,
what right do they have to sue the Environmental Protection
Agency for the failure to regulate that chemical’s
application up in Ohio or Illinois or in Minnesota?
And they do have the authority
to sue the Environmental Protection Agency or particular
chemical companies that are responsible.
So this trans-boundary movement
of these chemicals raises a very serious issue.
And also, you’ve got to think
about the fact that many of these cities get their water
supplies from these rivers. And they use filtration systems
that do not have the capacity to extract many of the pesticides
that are used. So water is typically filtered
by running it through sand to take out particulate matter.
Then it’s treated with chlorine.
It’s not normally treated with
activated carbon, which could bind to these
chemicals. Now, that should ring bells in
your head if you’re concerned about your own water intake,
because water is the most consumed food in your diet.
It should ring a bell that you
should be concerned about the quality of water in your tap and
you should think carefully about the wisdom of using activated
carbon at the tap, because it’s not likely that
the government has kept it perfectly safe.
So I’m going to scoot ahead
here with one final aspect of this story.
The atmospheric transport of
some of these chemicals was a surprise to many,
inside the agency as well as the scientific community.
I ran into this in California,
when I found that a chemical, dibromochloropropane,
that had been injected into the soil in cotton fields,
had actually volatilized and gotten up into the fog.
Anybody here from the Central
Valley? Well, the Central Valley of
California, which is sandwiched between the coastal range and
then the Sierras, is a flat basin,
it’s a former lakebed. And climatologically,
it’s interesting because a fog will settle on that area and
stay there for a good part of January,
sometimes December, six to eight weeks.
So what they found was DBCP was
actually volatilizing and it was detectable in the fog.
They found toxaphene that had
been applied in Texas in the Great Lakes.
Then they found atrazine in the
Great Lakes as well. So point six percent of
atrazine is deposited, in one study,
in rainfall. And the concentration of
atrazine in precipitation in some areas where it had not been
applied, was one part per billion.
And what did I tell you the
maximum contaminant level was? Three parts per billion.
Fairly striking.
So it’s moving long distances
in clouds and raining down and perhaps acting as a pre-emergent
herbicide to areas where it was never intended to be used.
So the degradation of the
chemical in aquatic environments is increasingly of concern.
The half-life is between
forty-one and 237 days. An average half-life of the
chemical of 159 days. And Lake Michigan is a
repository for atrazine because of its use,
particularly in Minnesota and Michigan,
Indiana, Ohio, and the pattern of rainfall in
that area. So it’s cold water,
it’s low productivity, it’s high pH,
low nitrate, and low dissolved oxygen,
all contribute to increased persistence of the chemical.
So the estimated half-life in
Lake Michigan is about thirty-one years.
So EPA conducted a study that
found that when they tried to figure out what the mass balance
was of atrazine or is of atrazine.
So atmospheric wet deposition
is about 2,493 kilograms per year.
The watershed loading directly
and surface water runoff to the lake is about 5,000 kilograms
per year. 2,500 kilograms exported to
Lake Huron and exported to Chicago by water diversions,
a more minor amount. And even the lake itself is
volatilizing the chemical. So recognizing that the
agricultural practice of using atrazine as an herbicide and
EPA’s neglect of this compound and misunderstanding of its
ecological behavior could cause a gradual buildup to 182,000
kilograms of the compound sitting in the lake.
It was really quite striking.
So I’m going to just pause with
reflections on the work of Tyrone Hayes,
who is a former chemical company employee,
a scientist who worked for Syngenta.
And Tyrone Hayes has been
responsible for some controversial work.
So he took his students and he
rented a tractor-trailer. And they drove across the
country, taking a look at the concentrations of atrazine in
leopard frogs. And what was interesting about
his finding, because he sampled from areas of the country where
the leopard frogs lived but atrazine was not used.
And then he went into the heart
of the Midwestern atrazine-use belt and sampled in those areas.
And he found obviously higher
concentrations in the areas where it was used,
but he also found that these frogs had both ovaries and
testes. So his argument that this
chemical is hormonally active, at least in the African clawed
frog. And he also is claiming that
there are important lessons here for humans, that this compound
could be also hormonally active in humans.
“So atrazine (he argues)
in exposed males that have ovaries in their testes also had
much smaller larynxes.” And larynxes are important if
you’re a frog, because it’s a way that you can
understand where other frogs are or other frogs can understand
where you are for reproductive success.
And it’s also recognized to
lower the testosterone levels in frogs.
So I’m not going to go further
today, other than to suggest that there’s a whole emerging
area of concern now about hormonally active compounds.
And atrazine is a good compound
to pay attention to. Okay, that’s it for today.
Thank you very much.

Leave a Reply

Your email address will not be published. Required fields are marked *