Lesson 8: Environmental Health, Pollution, and Toxicology Big Question: Why Are Even Tiny Amounts of...

Lesson 8: Environmental Health, Pollution, and Toxicology

Big Question:

Why Are Even Tiny Amounts of Pollutants a Major Concern?

Lesson 8 / ESRM 100 / University of Washington

Some Basics

Volcanic gases spewing from Mt. St Helens adversely affected air quality.


Terminology

•Pollution refers to an unwanted change in the

environment caused by introducing harmful materials or

by producing harmful conditions.•Contamination implies making something unfit for a

particular use through the introduction of undesirable

material. •A toxin is a substance that is poisonous (toxic) to

people and other living things.•Toxicology is the science that studies chemicals that

are or could be toxic.•A carcinogen is a toxin that increases the risk of

cancer.


Synergism

Synergism is an important concept. It is the interaction

of different substances, resulting in a combined effect

that is greater than the effects of the separate

substances


How Do Pollutants Get into the Environment?

• Point sources• Area sources (also called non-point sources)


Mobile Sources


Categories of Pollutants

•Infectious agents•Toxic heavy metals•Organic compounds•Thermal pollution•Particulates•Electromagnetic fields•Noise


Heavy Metals


Toxic Pathways

One pathway is biomagnification: accumulation or increase in the

concentration of a substance in living tissue as it moves through a food

web--also known as bioaccumulation.


Pathways for Mercury


Mercury and Minamata, Japan

A strange illness began to affect animals and people in the middle of the

20th century.

It was first recognized in birds, cats, and then families of fishermen. A vinyl

chloride factory on the bay used mercury in an inorganic form. Methylation

increased absorption into fish tissue from the water by a factor of 100.

See the Wikipedia article on Minamata Disease.

The crippled hand

of a Minamata

disease victim.

(Photo Wikipedia)

http://en.wikipedia.org/wiki/Minamata_disease


Organic Compounds

DHMO home pagehttp://www.dhmo.org/


Chemical Example of Use

Aldrin* Insecticide

Atrazine Herbicide

DDT* Insecticide

Dieldrin* Insecticide

Endrin** Insecticide

PCBs* Liquid insulators in electric transformers

Dioxins By-product of herbicide production

Selected Common Persistent Organic Pollutants (POPs)

* Banned in the U.S. and many other countries** Restricted or banned in many countries

Source: Data in part from Ann Platt McGinn, "Phasing out Persistent Organic Pollutants," in Lester R. Brown et al., State of the World 2000 (New York: Norton: 2000).


Dioxin

Dioxin-contaminated site in South Park area of Seattle,

WA


Hormonally Active Agents (HAAs)

HAAs are also persistent organic pollutants. HAAs

include a wide variety of chemicals, such as some

herbicides, pesticides, and phthalates. Studies link

HAAs to reproductive abnormalities among wildlife,

including Florida alligators

Do HAAs play a role in human diseases? Is there a link

with breast cancer?


Thermal Pollution


Wet and Dry Cooling Towers


Particulates


Chrysolite Asbestos

Removal of chrysolite asbestos in homes and public

buildings is extremely expensive, and there is little

evidence that the asbestos actually poses a hazard.


Electromagnetic Fields

If you think that cell phones don't generate much

power, see the

information from the University of Pittsburgh Cancer Institute

.

http://www.upci.upmc.edu/news/upci_news/072308_celladvisory.cfm

http://www.upci.upmc.edu/news/upci_news/072308_celladvisory.cfm


Noise PollutionSound Source Intensity of Sound (dB) Human Perception

Threshold of hearing ~0 Threshold of human hearing

Rustling of leaf 10 Very quite

Faint whisper 20 Quiet

Average home 45 Quiet

Light traffic (30 m away) 55 Quiet

Normal conversation 65 Quiet

Chain saw (15 m away) 80 Moderately loud

Walkman at maximum volume 100 Very loud

Rock music concert (close) 110 Very loud

Thunderclap (close) 120 Uncomfortably loud

Jet aircraft takeoff at 100 m 125 Uncomfortably loud

Takeoff of fighter jet (close) 140 Threshold of pain

Rocket engine (close) 180 Traumatic injury

Note: chronic exposure to very loud sound levels can cause hearing problems such as "ringing" in the ears.


Voluntary Exposure to Toxins


General Effects of Pollutants


Dose and Response

Large amounts of any substance can be dangerous,

while an extremely small amount can be relatively

harmless.

This is even true for water!

Copper, chromium, and manganese are some chemical

elements required by animals in small amounts but toxic

in higher amounts.

DHMO web sitehttp://dhmo.org


Dose-Response


Risk Assessment

Risk assessment is the process of determining potential

health effects of pollutants. It involves the following:• Identification of the hazard• Dose-response assessment• Exposure assessment• Risk characterization


Risk Management

Risk management requires us to make scientific

judgments in conjunction with technical, legal, political,

social, and economic considerations.

Risk assessment and risk management can lead to

arguments since the scientific opinions may be open to

debate.

The appropriate action may be to apply the

Precautionary Principle.

Lesson 8: Environmental Health, Pollution, and Toxicology

Questions? E-mail your TA. [email protected]

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