When we talk about environment,  first
of all we think about pollution. Pollution
is an environmental factor, which affects
everyone. Things like climatic change
can be something which people do not
feel immediately. Pollution is usually
felt immediately. And what is pollution?
Pollution is any substance or factor
occurring in the amount that makes
nuisance to humans or environment.
Nuisance means something unpleasant,
something not necessarily immediately
affecting health, but something that
makes your life uncomfortable. So
the fact whether something is
pollution or not, often depends on the
context. For example in some areas, let's
say sand.... Sand on the beach will be okay,
but sand in the street - not necessarily.
Pollution can be divided depending on
the factor, which makes pollution.
Pollution can be mechanical, like dust,
sand or some solid pieces, chemical - all
the chemical substances,
biological. Biological
pollution would be parasites, bacteria and
also viruses, so now we are affected by
biological pollution with the pandemic.
Pollution can also be  waves: radiation
like like radioactive radiation, but also
acoustic waves, like noise; noise is also
a kind of pollution, and even ordinary
light can be also polluting factor.
Pollution can also be divided into
natural and anthropogenic. This is an
example of natural pollution of water,
which is mud or silt, which is in the
river; and because of that the river is
muddy. In this example (this is from
Canada from the province of Nova Scotia)
this is the river, which as you
might notice, it looks as if it flew
backwards, because of the tide.  it's
the river mouth and you can see as if it
went backwards but that's not related to
the pollution. The pollution is
natural with this mud. And here we can
see the decantation pond
in the Nowa Huta. From the steelworks
all the metal pollutants are going to
the water into the decantation pond;
and this red color is from the iron,
from the compounds of iron.
Wastewater has to be treated and here is the example of
the wastewater treatment plant or sewage
treatment plant in Kraków - Płaszów; and
here you can see wastewater which is
brought in special containers, but
obviously most of wastewater is coming
through the sewage system and there are
several stages of wastewater treatment,
basically we can divide wastewater
treatment into mechanical and biological,
and there is also chemical treatment.
Chemical wastewater treatment is simply
coagulation of iron compounds so that
water does not contain iron and does not
have this rusty colour.  Mechanical
treatment is simply separation of wastes
and also sedimentation
and it is carried out in decantation
ponds. Biological treatment is based on
natural processes. The consortium of
microorganisms feed on the compounds of
nitrogen and also phosphorous; so they
feed on nutrients, because household sewage
contains  a lot of
nutrients; so then the bacteria and other
microorganisms simply remove nutrients
and in the biological part there is
anaerobic, aerobic and anoxic chamber; and here, with bubbles there is obviously
aerobic chamber or aerobic pond; and here
the activated sludge works in the
conditions with oxygen in an anaerobic
part there is no oxygen. And the effect
is clean water. Well, technically speaking
it is still sewage, but it has much
better or maybe not much, but better
parameters, or some parameters are better
than the parameters in the river to
which the wastewater is released; and in
this particular case this is River Drwina.
The sludge remaining
after mechanical treatment has to be
compacted, dehydrated and then it is
incinerated, together with the excess of
activated sludge, which also has to be
dehydrated, and so on.
The whole process of the management and
control of the work of the wastewater
treatment station is automatic.
We will not be talking about soil pollution
right now, but I would like to say something about
air pollution in the context of the
present situation, where there are much
less motor vehicles, much less cars in
the city of Krakow, and here the
information is that in spite of drastic
reduction in the number of cars,
there is still bad quality of the
air. Some people call it smog, some people
do not say that it is smog, 
nevertheless the air quality is bad and
the the cause might be, or at least there is
the hypothesis that it is because of
the neighboring municipalities,
where coal is still used for heating and
the city of Krakow is situated in the
valley, so the air is not circulating
freely and that's why the quality of air
is still bad. So car traffic is not
really that important for the quality of
air.
Industry that used to be one of most
polluting factors now is not that
significant in its contribution to air
pollution,
at least now, in Poland, the role of
industry in polluting the environment is
diminishing. This is because of the
regulations, stricter regulations
requiring some standards, air quality
standards and the due to the
modernization the problem is diminishing.
Here we have the example of the
cogeneration plant. Cogeneration and
power plant in Łęg.
Cogeneration plant is is a plant were both electricity is produced and heat is produced; and heat
is used for heating flats and
electricity is obviously used
for various purposes; so heat is not
released there simply to the water,
although it also happens. Releasing [hot] water to the river is also regarded pollution,
as I told you before, but here the heat
is not lost. The heat is used for heating
flats and various measures were taken to
get rid, for example, of sulphur in
the output
of the plant.
Radioactive pollution is a
kind of physical pollution connected
with the release to the environment of
radioactive substances. Radioactive
substances are elements or the compounds
of elements containing elements which
are radioactive. Radioactive isotopes occur
naturally in the environment and
radiation can be natural, in some areas
there can be elevated level of natural
radiation, as well. Radioactive pollution
is affecting cells of living organisms;
and this has many harmful effects to humans,
animals and plants and any living
organisms.
Apart from natural sources of radiation
there are also artificial sources of
radiation.  Artificial or human-made;
and there are nuclear tests. Obviously
there are various moratoria on nuclear
tests and nuclear tests are not done on the
daily basis, nevertheless
they cause serious damage and pollution.
I'll give you an example: in the fifties
a movie was made on the Utah Desert and
this was close to the Nevada nuclear
testing place and the 90 people of the
of the staff working with the
movie, actors and other filmmakers died
of cancer and there were more than
200 people working in the Utah desert.
And their deaths, the high death rate is
associated with the nuclear testing which
were close to the place where the movie
was shot. Although some argue that the deaths
were very prolonged in time, so it was
not just immediately or a few years
after the movie was shot. It was for
example in case of the most famous actor
in this movie - John Wayne. He died
more than 20 years later, in 1979, so some
people say that it is just a legend,
coincidence; nevertheless it looks very
suspicious, and obviously cancer develops
over years, so there is high possibility
that the people who died
of cancer that they were affected by the
radiation from the Nevada testing place.
Power plants  are also source of nuclear pollution, of
radiation, and I mean not only nuclear
power plants, but also conventional power
plants are source of radioactive
pollution; and obviously, in case of
nuclear power plants we think about two
things: the possibility of disaster as it
was in Chernobyl or in Fukushima, so these most notorious disasters, but
also the problem of the deposition of
nuclear wastes also nuclear wastes can be
source of radioactive pollution, if they
are stored improperly. So the deposition
of the nuclear wastes is a problem,
nevertheless some people consider
nuclear power plants much safer than
conventional power plants, so there is
discussion about it. Light can be also
polluting factor. Obviously the light is
necessary, especially for us. We are
diurnal animals (let say), diurnal
organisms. It means that 
we live during the day. We are active
during the day and at night when
it's dark we sleep. And nocturnal animals just the
opposite - they sleep during the day and
they are active at night. And what does it mean
that we sleep at night? That we need
darkness to sleep and we sleep much
better when it's dark; and in big cities
usually there is no time of darkness
because as we can say that big cities
never sleep so we have 24 hours a day. So what does it mean as well? This also means 
mean as well it also means not pay
animals. it disturbs animals birds, bats
are particularly affected. Birds are
mostly (apart from owls) diurnal. And we know  that bats are
nocturnal.
When we are talking about bats, it is
worth mentioning about the town of Nieuwkoop
in the Netherlands. This town is
known of bats; and the City Council
decided to change street lights from
white to red because red light is not
noticed by bats; and this will be a
compromis between streets being visible
and safe for people who walk at night
and the bats which got distracted by
white or yellow lights, by  the lights
which are usually put in the streets. Some
residents of Nieuwkoop protested at first,
because they were... they thought about the red light district in Amsterdam, which we know
what it is but finally probably they got
we know what it is, but finally they got used to the red lights and they understood
that it was good for bats so they
decided to keep red lights. Look at the
lighta at the University of Science and
Technology, AGH University of Science and Technology.
You can see that the lights are yellow, the
shade is yellow instead of white. The
lights are not covered, they are
visible from the sky, but they are not
bright they are yellowish. This is enough
to make people feel safe but this does
not distract birds, bats and so on. When
we are talking about Kraków, there is a
decision by the board responsible for
roads that street lights will be turned
off from midnight till 4:00 o'clock in the
morning, due to the lockdown, and because
of the lockdown people do not move so
much, they do not move without the
necessity so they do not move at night,
so they decided to turn the traffic
lights off. The decision is controversial,
because of the safety and we will not
discuss it; but let's look at the map of
the world at the points, and we can see
bright points, where the light is on and
we can see darkness; and in Europe North
America East Asia there are bright areas
in South America only some cities like
Rio de Janeiro or Buenos Aires will be
bright, and in Africa Cape Town,
Johannesburg
and not much more, Cairo as well, but most
of Africa is dark and southern part of
Australia Sydney, Melbourne also are
bright and in this map Krakow will be
dark, but maybe we will be able to see
the stars in Krakow, because normally we
can't see the stars even in the middle
of the night.
Anyway thank you for your attention and
till next time!
