>>In this lesson we're going to talk about damaged water or polluted water. Previously
we've talked about water quality issues from natural human activities: wastewater, excrement,
and also animal activities. We also talked about water quality issues from naturally
occurring compounds in groundwater. But in today's lesson we're going to talk about damaged
or polluted water, and this is a result of industrial activities that occur in a nation
as a nation industrializes more chemical processes. And there are a number of sources of potential
water quality concerns that emerge from those activities, and we'll talk about three categories.
We'll talk about nutrients. We'll talk about toxic organic compounds. And we'll talk about
heavy metals.
So the first category of compounds of concern, contaminants are nutrients, specifically nitrogen
and phosphorus. And how these often get into the environment are through, for example,
agricultural activities, fertilizers. Fertilizers are high in nitrogen phosphorus, and that
help the plants to grow. However, if not all that nitrogen phosphorus that's supplied gets
taken up by the plants, some of that can end up getting into the into the water, the surface
water, the groundwater. And this can cause several concerns. First, let's look at nitrogen.
Nitrogen can get into the water and can go from ammonia to nitrate. And nitrate in groundwater
specifically can cause a health concern, a concern that we call methemoglobinemia. I'll
say that again, methemoglobinemia, or otherwise known as blue baby syndrome. The nitrate can
get into the body and can affect the oxygen-carrying capacity of the blood, and can actually cause
a a blue appearance, and thus the name blue baby syndrome. And this can be fatal in infants
if the nitrate level is sufficiently high. And so this is a concern that can come from
nutrients in the environment.
The second nutrient of concern is phosphorus, and phosphorus can go into a receiving body
of water, for example, a lake. And the phosphorus may be the limiting nutrient to algae growth,
and so you may see a a massive growth of algae that we call an algal bloom. And this can
impact the environment in several ways. As the algae grow, and then diurnally daily a
daily cycle they grow, and then they die, and as they go through this process, they
can consume the oxygen in the water and can make the water not so attractive. It can even
result in death of fish, for example, and so that can be due to the phosphorus. The
phosphorus can come from fertilizers. The phosphorus historically can come from detergents,
laundry detergents. We would add a compound called tripolyphosphates to help bind the
hardness in the water, hardness calcium and magnesium could precipitate the soaps and
reduce the cleaning efficiency of the soaps, the detergents. And so this tripolyphosphate
would bind that calcium and magnesium and thus prevent the precipitation of the soap.
And thus we call that water hard water because of its impact on the the soap. So nitrogen
and phosphorus are two nutrients that can result from human activities, fertilizers,
that can have a negative impact upon water quality. And when that fertilizer is spread
out on the field, the farmland, we call that a nonpoint source of water pollution. It's
a nonpoint because you can't point and say, that right there, that's the pipe or that's
the place that's causing the water contamination. It's a very dispersed or widely spread out
or nonpoint source of pollution.
In contrast, the next compounds that we'll talk about are toxic organic compounds, and
we might think of compounds like PCBs, polychlorinated biphenyls. These are compounds that were discovered
as part of the organic chemistry revolution that occurred in the 20th century. So these
PCBs had very favorable properties. They were great insulators, and so they were used widely
in electrical systems as insulators. And they also had a low potential to ignite, to cause
flames, to combust, and so these were very desirable properties and made them very popular.
However, what we didn't realize at the time was that these compounds could also be potential
carcinogens, could potentially cause the formation of cancers. And so we recognized initially
the positive aspects without yet understanding some of the negative aspects.
Another class of compounds that fall into a similar category is pesticides. And one
of the better-known pesticides in this category would be DDT, dichlorodiphenyltrichloroethane.
Again, a chemical that came out of the organic chemistry revolution and very effective insecticide,
very effective at killing mosquitoes, and that's actually proved to save a lot of lives.
You see, mosquitoes carry malaria, and malaria can cause a lot of deaths and and does around
the world. And so the DDT that kills mosquitoes prevented the spread of malaria, and so it
was widely hailed as a wonderful advance, saved a countless number of lives. What we
didn't realize at the time was that DDT also affected the reproduction in the bird population,
and all of a sudden as a result of DDT being used in the environment, the number of birds
began to decline. And Rachel Carson wrote a famous book called Silent Spring, Silent
Spring. In the springtime it was silent because the bird population had declined to the point
where there weren't so many birds to be singing in the spring, and this was a side effect
of the use of DDT. So once again, we initially understood the positive effects, but it wasn't
until later that we begin to recognize the negative effects.
Two other examples of toxic organic chemicals, and one would be chlorinated solvents. These
are solvents that are again an outgrowth of the organic chemistry revolution, for example,
tetrachloroethene or perchloroethylene, also known as PCE. Widely used as a solvent, very
effective at degreasing and paint stripping, widely used in many operations. And unfortunately
this, as with any chemical, this PCE as it was used found its way into the environment,
and it would be get into the groundwater, for example. And there is a movie from many
years ago that talks about this situation where this PCE got into the groundwater, and
it impacted the water supply of a community. And the the movie was called "Civil Action."
John Travolta starred in this movie, and so again it was an example of an organic chemical
that was very effective at its intended purpose, but it's also a potential carcinogen.
And then the final class of organic compounds we'll talk about are pharmaceuticals, drugs--the
active ingredients in drugs, or pharmaceuticals. And these obviously have great health benefits,
but these go through the body and come out of the body often unaltered. And they go through
the the wastewater treatment plant potentially unaltered, and they make their way into the
environment. And there's uncertainty about the long-term effects of low levels of these
pharmaceuticals in the environment. So in all these cases, we have chemicals that were
developed as a result of organic chemistry. And we see the positive benefits, but we also
have to be aware of the potential negative effects on the environment and on human health.
The third class of compounds we want to talk about are heavy metals. Heavy metals are used
widely in industrial activities, for for example, chrome-plated bumpers is the example that
comes to my mind. Metal plating, many times we metal plate, do metal plating, chromium
and other metals, copper plating that helps protect the surface of the metals and extends
their their usefulness and their lifetime. But these heavy metals can find their way
into the environment. And so just to cite one other movie. This one may is little more
recent, maybe people may remember this movie a little bit better than the "Civil Action"
movie. And that's the movie "Erin Brockovich," and this was a movie where chromium got into
the environment. It was used in a energy production process, and it got into the environment,
got into the groundwater. And it made it to the water supply of a community, and there
were elevated incidence of cancer in this community.
So we see the example of heavy metals getting into the environment and having a very positive,
beneficial use, but then also have to be aware of the potential health and environmental
concerns. In Northeast Oklahoma we have an area called Tar Creek, former lead and zinc
mines in the northeast part of the state. And as a result of those mining activities
and the aftermath of those activities, we have heavy metals that have gotten into the
the waters in the area around Tar Creek. And my colleague, Dr. Bob Nairn, is doing work
on engineered treatment wetlands to help take that water and help remove those metal in
engineered wetlands, so the water going into the receiving streams is of a much higher
quality and has less effect on the environment and human health, and so that would be an
example for heavy metals.
So we see in all of these cases that these chemical processes produce materials that
are very helpful to mankind, but there's potential side effects, and so this leads to the concept
that we call sustainable development. Development is good because development reduces infant
mortality. Development allows us to have longer lifetimes. But that development also can have
potential side effects. And so we need sustainable development, development where we benefit
from the positive aspects of the industrial activities, but we understand the potential
negative effects on the environment, and we learn from lessons of history so that when
we develop new products we take into account green chemistry, green processing as an effort
to as we develop new compounds that we make sure that we reduce the potential risk to
the environment and human health. But we certainly want the positive aspects, and so we certainly
want the development, but in a sustainable way.
And so an example I think of this is Thailand. We happen to be part of a cooperative graduate
program at Chulalongkorn University in Bangkok, Thailand. University of Oklahoma along with
several other universities helped to deliver a graduate programs in chemical engineering,
developing new chemical processes, helping to expand the chemical industry in Thailand,
but at the same time environmental engineering. Let's understand the potential consequences
to the environment. And while we're growing the industry, let's also grow the environmental
awareness so that we can have sustainable development. And this is a lesson that many
other countries can benefit from. As China, as India, as Brazil begin to expand their
industrial activities, they need to do it from a sustainable way so that they have the
benefits of development in the industrial sector, while mitigating, minimizing potential
concerns to human health and the environment.