Evaluation of Fundamental Concepts in Environmental Science and Technology

Definitions:

Environment
- All external factors, living and non-living (chemical and energy), that affect you or any other organism.

Environmental Science
- "is the science of the complex interactions that occur among the terrestrial, atmosphere, aquatic, living and anthropological environments."

Manahan defines Environmental Science in this way
" the study of the earth, air, water, and living environments and the effects of technology thereon."

Alternative definition-
The study of how life forms interact with each other and with the non-living environment of matter and energy.

Goals of Environmental Science
- To learn how the earth works and how to sustain it and the living organisms (including us) that live on it.

Popular Viewpoints:

Which world view do you feel is most correct?

Sustainability Defined

Sustainable
- From the New American Heritage Dictionary
  1. To keep in existence or effect; maintain.

  2. To supply with necessities or nourishment.

  3. To keep from falling or sinking.

  4. To support the spirits or resolution of.

  5. To endure or withstand: sustain hardships.

  6. To experience or suffer (loss or injury).

  7. To affirm the validity or justice of: Sustain an objection.

  8. To prove or corroborate; confirm.

    [ Latin sustinere, to hold up.]


Pollution

"Any undesirable change in the characteristics of the air, water, soil, or food that can adversely affect the health, survival, or activities of humans or other living organisms"

Pollutant

"A substance present in greater than natural concentration as a result of human activity that has a net detrimental effect upon its environment or upon something of value in that environment.

Pollute - To make impure or unclean, to contaminate

Types and Sources of pollution:

Natural Pollution

Nature is not perfect and contributes to what we define as pollution

Anthropogenic Pollution

Pollution from man is termed anthropogenic pollution

Pollution Prevention

Two methods of attack:

Prevention is always less expensive and exposes less people to hazard. It does require cooperation.

Examples of water, air and geological pollution are evident and we will study several of these complex interactions

Why is environmental chemistry difficult to predict and comprehend at first?

  1. Previously only one concept has been studied at a time

  2. Nature mixes all phases, interactions, interdependencies and media together for the final result simultaneously

Almost nothing in nature can be isolated

Figure 1.1, Illustrates the interaction between the five environmental "spheres"
water, air, earth, life, technology.

Figure 1.1. Illustration of the close relationships among the air, water, and earth environments with each other and with living systems, as well as the tie-in with technology.

(hydrosphere, atmosphere, geosphere, biosphere, and technology which is strictly an anthropogenic development)

Classical spheres and the related environmental spheres outlined

Hydrosphere

Earth's water is contained in this layer and phase

It cycles in the hydrologic cycle

70% of earth's surface is covered by water

Water is essential and required for all life

Medium in which most life sustaining chemical reactions occur

Water takes part in many life sustaining reactions and many environmental transformations

Atmosphere and air

Protective blanket

Oxygen supply (ultimate oxidant for life)

Lithosphere temperature moderator (0-100°C)

Gas transport (O2, CO2, O3, NH3, NO2)

Part of the hydrologic cycle

Complex interactions in air pollution including chemically participating in reactions

Transparent and absorbent to different electrochemical energy

Geosphere (Earth)

Earth's solid material including core and rock and soil.

Lithosphere a 50-100 km outer mantle and the surface crust containing soil that supports life.
It also contains the natural waters, streams, Rivers, lakes, ground water and subsurface aquifers.

Minerals required for life support of plants, animals and some bacteria

Water is involved with soil conversion and mineral formation also

Soil, the substrate for continental plant, growth and ultimately the recipient of energy input from the Sun.

Support for much of the animal life since plants are the start of the food chain for much of the biosphere.

Biosphere (Life)

All living things on earth comprise the biosphere

Interspersed as integral part of all spheres including the Geosphere, Hydrosphere, and Lithosphere
Also involved in producing soil from rock as well as the plant life in the soil and in the water

biotic and abiotic

All living organisms and the environmental aspects pertaining to them are referred to as biotic

abiotic is all other environmental aspects.

The discipline that deals specifically with the effects of environmental chemical species on life is environmental biochemistry.

Toxicological chemistry is the chemistry of toxic substances with emphasis upon their interactions with biological tissue an living organisms.

Life in the biosphere requires advanced and complex chemical reactions and interactions

Life is totally dependent on its interaction with its environment for its maintenance and growth.

In human terms also the quality of life

Cycles

These spheres are involved in many cycles and are involved each other

biogeochemical cycles is the term used to describe this interrelated interaction of cycles

Technology

A modern concept and environmental change based on engineering and scientific principles.

Technology sustainable applied is a productive and appropriately applied endeavor.

Applied at the degradation of its surrounding environment, it degrades its environment.

Until very recently technological advances were made without heed to environmental impact.

Now environmental consequences and a sustainable environment are a consideration.

Environmental Chemistry - is a technology that is used to evaluate, understand, predict, model, and assist in the correction of anthropogenic environmental interactions.

Environmental Chemistry

Manahan defines as:
- the study of the sources, reactions, transport, effects, and fates of chemical species in water, oil, and air environments and the effects of technology thereon.

environmental chemistry "is more complicated and difficult than 'pure' chemistry."

Traditional chemists usually deal with "clear-cut concepts of relatively simple, well-defined, though often unrealistic systems, they may find environmental chemistry to be poorly delineated, vague, and confusing."

"More often than not, it is impossible to come up with a simple answer to an environmental chemistry problem."

Chemical Analysis, Analytical Chemistry and Environmental Chemistry

Manahan's perspective

"Thus, chemical analysis is a vital first step in environmental chemistry research."

The significance of chemicals in the environment span a range form % levels to trace quantities such as parts per trillion (ppt).

"Analytical chemistry is a fundamental and crucial part of that endeavor but is by no means all of it."

"... a 'brute-force' approach to environmental control, involving attempts to monitor each environmental niche for every possible pollutant, increases employment for chemists and raises sales of chemical instrumentation, it is a wasteful way to detect and solve environmental problems, degenerating into a mindless exercise in the collection of marginally useful numbers."

What he is trying to get at is - analysis is necessary and important but the use of analytical data and their relationships are far more important than just the measurement of a component of a very complex system in the environment.

Perspective

Therefore: Analysis is important, but it is not as important as understanding the relationships of the many chemically active and interactive components in environmental systems.

Ecology

The science that deals with the relationships between living organisms and with their physical environment and with each other.

ref.
Smith, R. L, Elements of Ecology, 3rd ed., (NY: Harper Collins Pub., Inc., 1992)

Applied ecology - the branch of ecology that deals with predicting the impacts of technology and development and mass recommendations to minimize adverse impact

Habitat - the environment in which a particular organism lives.

Niche - the role of an organism in a habitat

Terrestrial environment - is based on land

Freshwater environment - fresh water ecological systems
standing water and running water habitats

Marine environment - ocean habitats
neritic zone - shallow water and continental shelf
oceanic region - deeper water of the ocean

Energy and Cycles of Energy

The Earth receives approximately 1 kw (kilo watt) of energy per square meter per day.

The electromagnetic radiation has a bandwidth covering ultraviolet - visible - infrared radiation wavelengths

Its maximum flux density is at 500 nm with approximately 86% in the visible range with approximately 7% in UV and 7% in IR regions.

Relationship between electromagnetic characteristics

Wavelength and frequency are related to the energy of a photon, E, by Planck's constant h, 6.62x10-34J sec,
and c, the velocity of light (3.00 x 108 m /sec) in a vacuum.


Relative Energy

The higher energy radiation has, the smaller wave length and the higher frequency - thus - in order of decreasing energy

g-ray > x-ray > ultraviolet > visible > infrared > microwave > radio-frequency

Example of visible light energy in this region using the yellow visible light of the Na line

The most well known line in the Na spectrum is 589nm (5890.0 Å ) near the Sun's maximum energy flux

Changing to electron volts as units:


Some electromagnetic energy considered to be in a category called ionizing radiation

What happens when you are Irradiated with ultraviolet frequencies such as at the beach?

Let us examine the bond energy of some molecules.
Molecule Bond Bond Energy in kJ/mol
Methane H-CH3 438.4 ± 1
CH3-C6H5 317.1 ± 6.3
CH3-CH2CCH3 308.4 ± 6.3
Ethyl alcohol H-OC2H5 436.0 ± 4.2
F-CF2Cl 490 ± 25

Energy conversion of light energy into biomass and the start of the food chain

water, air, and even soil are recycled in various cycles

Energy however is a one way process that starts with the input from the Sun to the Earth.

CO2 + Water + El. Radiation (Sun) ----> Biomass

This is not an efficient process and losses occur in the conversion process due to the effects described in the thermodynamic laws

Biomass eventually degrades and energy is lost as low grade energy, usually IR radiated from the Earth.

Fossil fuels (oil, coal, nat. gas) is stored biomass from energy originating from the Sun and converted over millions and billions of years.

In the last 2 centuries we (humans) have switched form biomass energy use to stored fossil fuels for 90% of our industrial energy need. This excludes food production which is still solar based.

Figure 1.2, Describes the conversion of the Sun's electromagnetic energy into biomass.

Figure 1.2. Energy conversion and transfer by photosynthesis.

Technology

Provides
  1. alterations in the environment and pollution problems

  2. alternatives, evaluation and solutions

Major ways modern technology has contributed to environmental alterations and pollution

Technological processes are now being designed with environmental factors considered

Figure 1.3, Depicts a manufactured process with key environmental impacts identified.

Figure 1.3. A manufacturing process viewed from the standpoint of minimization of environmental impact.

New applications of technology that assist in making them more environmentally compatible.

Environmental designs consider minimization of material use, pollution and energy consumption

Recycling of materials, energy process waters. Energy and material closed loops are not attainable but are being approached

Use of best available technology including advanced catalysts and computerized control to optimize



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Revised 4/23/99.