2-3-1: Toxicology & Pollutants

murmerlastUrban and Civil

Nov 16, 2013 (3 years and 6 months ago)

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2
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3
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1: Toxicology & Pollutants


After this lecture you should be able to:


Define the terms toxic, pollution/pollutant, contamination,
synergism, and biomagnification, and identify examples if each.



Describe the source type of various pollutants.



Identify the classifications and characteristics of major
environmental pollutants.



Evaluate pathways by which pollutants move through an
ecosystem.

What is Toxic?


A disease is an impairment on an individual’s well
-
being and/or ability
to function.


Disease results from an inability of an individual to adjust to changes in
environmental conditions.


Toxins are substances that can lead to such impairment and/or
dysfunction.


Toxins can enter biological systems in a variety of ways including:


Consumption


Respiration


Physical Contact


Exposure

Pollutants & Contamination


Pollution refers to an unwanted change in the environment
caused by the introduction of harmful materials or the
production of harmful conditions.


Contamination occurs when pollutants make something unfit
for a particular use.


Synergism is a type of contamination where two or more
primary pollutants interact resulting in in a secondary condition
in which the impact is greater than the sum of the impacts of
the original pollutants.

Pollution Sources & Distribution


Pollutants can enter a system in
a variety of ways.


Point
-
source pollution can be
traced to its
point(s
) of origin.


Nonpoint
-
source pollution is
diffused over an area and can
not be traced back to a single
source.


Mobile
-
source pollution comes
from sources that may move
in/out of a system.

Biomagnification


While some pollutants can can
be processed by biological
systems, others persist.


These pollutants undergo
biomagnification, where by the
concentration of a particular
pollutant increases as it moves
through the food web.


Bioaccumulation is the
process by which higher
-
order consumers take in
more of a pollutant due to
the higher amount of
biomass they consume.

Types of Pollutants


Pollutants vary widely in their type and the effect they can have
on humans, other organisms, and the environment as a whole.


Major categories of pollutants include:


Environmentally Transmitted Infections Agents


Heavy Metals


Organic Compounds


Persistent Organic Pollutants


Hormonally Active Agents


Particulates

Types of Pollutants (Cont.)

Environmentally Transmitted
Infectious Agents


Description: Pathogens
(bacteria/viruses) that
spread when specific
conditions promote them.


Pathway: Person
-
to
-
person
contact, water, food, hosts,
“unclean” environments.


Examples:
Legionellosis

(air),
Cryptosporidium (water),
Malaria (host), Salmonella
(food).

Heavy Metals


Description: Metallic elements
with particularly high atomic
weights.


Pathway: Metals leech into soil
through mining, byproducts of
production and waste.


Examples: mercury, lead,
cadmium, selenium.


NOTE: All of these metals are
naturally found in the human
body, but are lethal at a certain
dose.

Types of Pollutants (Cont.)

Organic Compounds


Description: Carbon
-
based
compounds produced by living
organisms (or synthetically by
industry.)


Pathway: Biological processes
and consumption.


Examples: methane, urea.


Persistent Organic
Pollutants (
POPs
)


Description: Synthetic, fat
soluble, organic compounds that
contain highly reactive elements
(like chlorine), and are not easily
broken down.


Pathway: Fat solubility make
them prone to biomagnification
and sedimentation.


Examples: dioxins, many
herbicides and pesticides


Types of Pollutants (Cont.)

Hormonally Active Agents
(
HAAs
)


Description: A type of POP that
cause developmental and
reproductive abnormalities.


Pathway: Introduction to
biological systems result in
changes in biochemical
compounds and/or processes.


Examples: many herbicides,
pesticides, and plastics.


NOTE: Many suspected
HAAs

are under review, but very few
have direct causal proof.


Particulates


Description: Small particles
released into and suspended
in the atmosphere.


Pathway: combustion of
materials, volcanic
eruptions, etc.


Examples: soot, asbestos
(may include other
categories.)


What’s the MATTER with Pollution?


Not all pollutants are matter.


Different forms of energy can be considered pollutants and can
have an adverse impact on environmental systems and humans
alike.


Forms of energy pollution include:


Nuclear Radiation


Thermal Pollution


Electromagnetic Fields


Noise Pollution

Other Forms of Pollution

Nuclear Radiation


Description: Small, sub
-
atomic
particles (
a
/
b
) or energy waves
(
g
) that can move through
certain substances.


Pathway: Particles and energy
can collide with other
atoms/molecules causing
changes in structure and
function.


Examples: nuclear waste, x
-
rays, ultraviolet light.

Thermal Pollution


Description: Chronic or acute
releases of excess heat into air
or water.


Pathway: Changes in
temperature change living
conditions and can alter water
quality of aquatic ecosystems.


Examples: Electric power plants
release heated water.

Other Forms of Pollution (Cont.)

Electromagnetic Fields


Description: A zone generated
by the presence of electrically
charged particles.


Pathway: (unclear)


Examples: power lines & cancer
clusters”, cell phones &
Alzheimer’s.


NOTE: Much research has been
done to establish a causality
relationship between EMF and
various conditions, but are not
conclusive.


Noise Pollution


Description: Unwanted sound
that disrupts natural activities or
patterns.


Pathway: Anything that makes
noise can contribute to total
noise pollution.


Examples: Airplanes, vehicular
noise, industrial noise.


NOTE: Noise pollution can
contribute to human fatigue due
to sleep pattern disruptions, and
has been connections with
changes in mating and feed
patterns of other animals.


Not All Pollutants Are Created Equal


As demonstrated, each category of pollutant has a unique set of
characteristics that govern how it moves through and effects
environmental and biological systems.


However, each category has many specific agents, each of which
behave differently.


To toxicity of a particular pollutant is assessed by the size or
dose

of the pollutant that results in the impact or
response
.

End of
Lecture Objectives


Define the terms toxic, pollution/pollutant
, contamination,
synergism, and biomagnification, and identify examples if each.



Describe the source type of various pollutants.



Identify the classifications and characteristics of major
environmental pollutants.



Evaluate pathways by which pollutants move through an
ecosystem.