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INDUSTRIAL & ENVIRONMENTAL
BIOTECHNOLOGY
Course # KIBGE-707
AFSHEEN AMAN, Ph.D.
Assistant Professor
Industrial Biotechnology Section
Dr. A.Q. Khan Institute of Biotechnology & Genetic
Engineering (KIBGE)
University of Karachi
Pakistan
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BIOAVAILABILITY &
TOXICITY OF POLLUTANTS
Course # KIBGE-707
ECOTOXICOLOGY
 The
term ecotoxicology was coined by
Rene Truhaut in 1969
 Branch
of toxicology concerned with
the study of toxic effects, caused by
natural or synthetic pollutants, to the
constituents of ecosystems, animals
(including human), vegetables and
microbes”
 Ecology
in the presence of toxicants 3

A 5-steps understanding process useful for
research/regulation
• Release of pollutant into the environment
• Transport and fate into biota (with/out chemical
transformation)
• Exposure to biological and ecological system
• Understanding responses and/or effects
(molecular to ecological systems)
• Design experiments, remediation, minimization,
conservation, and risk assessment plans to
understand, eliminate, prevent or predict
environmental and human health pollutions
situations.
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Ecotoxicity
• Subject of study of the field of ecotoxicology
refers to the potential for biological, chemical or
physical stressors to affect ecosystems.
Such stressors might occur in the natural
environment at densities, concentrations or
levels high enough to disrupt the natural
aspects that comprise the ecosystem.
•Biochemistry
•Physiology
•Behavior
•Interactions of the living organisms
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Bioavailability of a pollutant

The extent to which a pollutant is available
to living things. Some compounds are very
bioavailable to plants and animals because
they are soluble in water; different
compounds are soluble to different
degrees.

If a substance is insoluble in water, or
hydrophobic, it is generally not
bioavailable.

Hydrophobic compounds have an
affinity for lipids and thus do not
associate with water.

Bioavailability will vary with soil
structure and organic matter content.

The higher the clay content of a soil,
the more likely a pollutant is to be
bound to the soil and therefore
unavailable for plant uptake.
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
Clay soils have a smaller particle size,
and thus more surface area. This high
surface area provides for more exchange
sites.

Organic compounds that have a charge
are subject to these exchange sites and
become less bioavailable.

High organic matter content in the soil
will bind lipophilic (i.e. hydrophobic)
compounds, making petroleum
hydrocarbons less available.
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TYPES OF POLLUTANTS
Greenhouse Gases:
Carbon dioxide and methane are two of the
most important of these gases, called
greenhouse gases because they trap heat
in the earth's atmosphere.
This is already causing severe problems
around the world and the situation will
only get worse.
The rising temperatures will likely lead to
more severe weather events, cause shifts
in natural communities, and probably lead
to greater species extinction rates, among
numerous other effects.
Pesticides:

A broad group of chemicals that enable
us to live more comfortable lives by and
large, but whose main purpose underlies
the central problem with pesticide
pollution.

A lot of these chemicals will wash into our
rivers and streams and cause direct
toxicity to fishes, and may work their way
up the food chain to affect birds, bears,
whales, and other predatory wildlife,
including humans.
Insecticides
 Fungicides
 Herbicides
 Plant-growth regulator
 Other compound

They are all poisons
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 Some
of these pesticides will persist
for long periods of time in the
environment.
 DDT
was a pesticide used for along
time in the US (and is still being
used in parts of the world for
mosquito control), but has been
banned in the US since 1972.
 Yet
we still find DDT in our
environment, sometimes at very
high levels.
Heavy metals:
 Metals are continuously released into the
biosphere by volcanoes, natural weathering
of rocks but also by numerous
anthropogenic acitivities, such as mining,
combustion of fuels, industrial and urban
sewage and agricultural practices.

On a global scale there is now abundant
evidence that anthropogenic activities have
polluted the environment with heavy metals
from the poles to the tropics and from the
mountains to the depths of the oceans.
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Most heavy metals, such as mercury, are
a natural part of the earth's crust, and
would be slowly released into the
environment over time just by weathering
of soils and rocks.
 However, our consumption of fossil fuels
has greatly increased the introduction of
heavy metals into our environment.

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
The world-wide emissions of metals to
the atmosphere by natural sources is
estimated as (thousand t yr-1):
Ni: 26,
Zn: 4,

Pb: 19, Cu: 19,
Cd: 1.0, Se: 0.4
As: 7.8,
Whereas, from anthropogenic sources
(thousand t yr-1):
Pb: 450, Zn: 320, Ni: 47,
As: 24, Cd: 7.5, Se: 1.1
Cu: 56,
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
It is estimated that half of the mercury
introduced into the environment today
is due to human sources.

The problem is mercury, as well as
other heavy metals, that cannot be
detoxified.

Once it is in the environment, it is here
for good. Toxic effects of heavy metals
vary.
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
Mercury is a potent toxin in people
targeting nervous tissue, but targets
other tissues in other animals.

The effects of heavy metals can also be
quite severe, since plants and animals
have no natural ability to deal with
heavy metals specifically and heavy
metals do not have any functions in our
bodies.
List of Environmental Issues





Climate change — Global warming • Fossil fuels •
Sea level rise • Greenhouse gas • Ocean
acidification
Conservation — Species extinction • Pollinator
decline • Coral bleaching • Holocene extinction
event • Invasive species • Endangered species
Dams — Environmental impacts of dams
Energy — Energy conservation • Renewable
energy • Efficient energy use • Renewable energy
commercialization
Intensive farming — Overgrazing • Irrigation •
Monoculture • Environmental effects of meat
production







Land degradation — Land pollution
• Desertification
Soil — Soil conservation • Soil erosion
• Soil contamination • Soil salination
Land use — Urban sprawl • Habitat
fragmentation • Habitat destruction
Nanotechnology — Nanotoxicology
• Nanopollution
Nuclear issues — Nuclear fallout • Nuclear
meltdown • Nuclear power • Radioactive
waste
Overpopulation — Burial
Ozone depletion — CFC
Toxins — Chlorofluorocarbons • DDT
(dichlorodiphenyltrichloroethane)
• Endocrine disruptors • Dioxin • Heavy
metals • Herbicides • Pesticides • Toxic
waste • Bioaccumulation
 Waste — E-waste • Litter • Waste
disposal incidents • Marine debris •
Landfill • Recycling • Incineration
 Genetic engineering — Genetic pollution
• Genetically modified food
controversies

THANK YOU
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