Environment and Pollution

The Environment

• It is the sum total of human surroundings, consisting of the atmosphere, hydrosphere, lithosphere, and biota
• Humans are totally dependent on the environment for life
• The atmosphere provides air, the hydrosphere provides water, and the lithosphere provides soil to grow vegetables

Fouling the environment

• Fouling the environment (pollution) by the products of industrial society can have many harmful consequences
• Damage to human health is of greatest concern

Outdoor vs. Indoor

• There is increasing concern about exposure to harmful pollutants within the indoor environment at home and work
• Levels of harmful pollutants can often be higher indoors compared to outdoors
• This is especially true in workplaces where workers can be exposed to high levels of toxic substances

Function of an environmental analyst

• Pollution is mainly chemical in nature
• Environmental analysts are important to society
• They keep people informed about the quality of the environment
• They alert the public to major pollution incidents

Biosphere

• It is defined as the “sphere of living organisms distribution”
• It is the part of the environment where life exists
• It consists of the hydrosphere (oceans, rivers, lakes), the lower part of the atmosphere, the upper layer of the lithosphere (soil), and all life forms

Biogeochemical Cycle

• Spheres act as reservoirs of environmental constituents and are linked through physical, chemical, and biological processes
• There is constant exchange of material between them
• Chemical substances can move through the biosphere from one reservoir to another
• Transport of constituents is described as a biogeochemical cycle
• Biogeochemical cycles of many elements are linked to the hydrological cycle
• The hydrological cycle moves water-soluble nutrients and pollutants through the environment

Biogeochemical Cycle Continued

• If all components of the cycle are identified, amounts and rates of material transfer are quantified, then the term "budget" can be used
• Both beneficial and harmful pollutants are transported through biogeochemical cycles with far-reaching consequences
• Commonly discussed biogeochemical cycles are those of macronutrients like carbon, sulfur, nitrogen, and phosphorus

Box Model

• The cycle is illustrated as a series of compartments (reservoirs) and pathways between them
• Each reservoir can be viewed in terms of a box model
• If the input into a reservoir equals the output, the system is in a steady state
• If the input exceeds the output, there will be an increase in the amount of substance

Box Model Examples

• Pollution builds up in environmental systems since pollutants are often added at rates greater than the rate of natural processes that remove them
• An example is CO2 concentration on the Earth
• If the output is greater than the input, the amount of substance in a reservoir will decrease
• An example is the depletion of natural resources

Steady State of Natural Systems

• It is debatable whether natural systems tend towards some steady state or equilibrium in the absence of human activities
• Natural systems are dynamic, and both natural and human disturbances lead to change, although at different time scales
• Natural changes to biogeochemical cycles generally occur over geologic time scales and have maintained the balance of nature

Human-Induced Disturbances

• Since the industrial revolution, and especially in the last 50 years, human activities have caused significant perturbations in biogeochemical cycles
• Effects of these disruptions are becoming apparent and are likely to become more severe
• Serious environmental problems caused by disruptions of biogeochemical cycles include:
• Global warming
• Acid rain
• Depletion of the ozone layer
• Bioaccumulation of toxic wastes
• Decline in freshwater resources

Depletion of the Ozone Layer

• The 2015 Antarctic ozone hole area was larger and formed later than in recent years
• On Oct. 2, 2015, the ozone hole expanded to its peak of 28.2 million square kilometers (10.9 million square miles)
• That area is larger than the continent of North America

Decline in Freshwater Resources

• Populations of freshwater mammals, reptiles, amphibians, birds, and fish have declined by 76% since the 1970s

Major Human Impacts on Biogeochemical Cycles

• Some impacts on biogeochemical cycles include:
  • Fossil Fuel Combustion, Clearing of forests
  • Fossil Fuel Combustion
  • Fossil Fuel Combustion, Fertilizers
  • Detergents and Fertilizers
• These lead to:
  • Global Warming
  • Acid Rain
  • Acid Rain, Eutrophication
  • Eutrophication

Industrial emissions of some toxic substances

• The extent of human impacts on biogeochemical cycles can be illustrated by comparing the contribution of anthropogenic emissions to the atmosphere with natural emissions
• For some toxic substances, the contribution of industrial emissions is even more striking
• The ratio of anthropogenic to natural emissions is:
  • 3:1 for arsenic
  • 5:1 for cadmium
  • 10:1 for mercury
  • 28:1 for lead

Environmental Pollution

• It is defined as the addition of a substance by human activity to the environment that can cause injury to human health or damage to natural ecosystems
• The definition excludes "natural pollution", although natural processes can release harmful substances as well
• Different categories of pollution:
  • Chemical
  • Physical
  • Biological
  • Radioactive
  • Aesthetic

Natural and Synthetic Pollutants

• Most substances considered pollutants are natural constituents that are harmless in natural concentrations
• Sources of pollution are:
  • Domestic
  • Industrial
  • Agriculture
  • Transportation
  • Warfare

Geographical Scale of Pollution

• Pollution can be classified by geographical scale:
  • Local: affecting a single field, stream, or city
  • Regional: affecting part of a country, a whole country, or an entire continent
  • Global: affecting everywhere such as global warming due to CO2
• The distinction is not always clear-cut

Pollution and Growing Population

• The number of pollution sources is rising due to growing industrial development
• The growing population drives an increase in pollution
• The world's population has more than doubled over the last 50 years and is expected to increase by another 2–4 billion soon

Continued Pollution and Growing Population

• Demand for energy and resources to feed, clothe, and house a growing population causes a parallel increase in waste production
• Rising standards of living also place more stress on the environment
• Expect more widespread and severe pollution problems in the future unless measures are taken to control pollution
• The growing population and consumer society lead to depletion of non-renewable resources
• Resource conservation is important to leave enough for future generations

Antiquity Environmental Pollution

• Problems of environmental pollution have been known since antiquity, but are now being widely recognized
• Air pollution has been around since ancient humans used fire for heating and cooking
• In antiquity and the Middle Ages, town air was polluted by burning wood and coal, and by ore smelting
• Wastes were dumped into the streets leading to many epidemics

River Pollution

• The amount of Dissolved Oxygen (DO) is an indicator of the cleanliness of water
• Normal pollution load: self-purification of stream biota
• Over-loaded pollution: biota cannot handle it and die off, killing the stream

Industrial Revolution Pollution

• The Industrial Revolution accelerated the release of pollutants into the environment
• It originated in the north of England in the late 18th/early 19th century and spread
• Rapid industrialization continues throughout the world
• The variety and extent of pollution are now greater than ever
• Natural processes can no longer cleanse the environment
• Natural ecosystems can only accommodate a certain capacity of pollution before being overloaded
• Harmful consequences follow when pollution levels reach a critical limit

Technological Progress

• Technology provides enormous power over nature for better or worse
• Medical and technological advances improved healthcare, provided protection against disasters, increased living standards, eliminated dangerous jobs and improved work safety
• People now have the ability to destroy isolated ecosystem, all life, including human life

Environmental Problems of the 21st Century

• Global warming and climate change
• Stratospheric ozone depletion
• Acid rain
• Urban pollution
• Haze from forest fires
• Declining water resources
• Eutrophication
• Desertification
• Solid and toxic waste disposal
• Radioactive waste disposal
• Depletion of resources

Environmental Success Stories

• It is not all doom and gloom, there have been many environmental success stories
• Those successes have so far been mainly limited to the developed nations
• Air quality of most cities in Western Europe and North America has significantly improved
• Concentrations of SO2 and smoke have steadily decreased
• The introduction of catalytic converters has reduced the emissions of automotive air pollutants

Continued Environmental Success Stories

• Many countries have phased out the use of lead in petrol
• Strict controls have been imposed on the transport and disposal of toxic wastes
• There is increasing emphasis on "clean technologies"
• Concepts such as recycling, reuse, lifecycle analysis, sustainable development, energy conservation, "eco-safe" methods, and environmental impact assessment (EIA) are increasingly implemented
• There is considerable research in developing alternative, nonpolluting energy sources such as solar and wind energy

Developing Countries

• Improvements found in developed countries are not evident in developing countries
• The previously unspoiled environments have regressed
• there is cause for optimism

Effects Of Pollution

• It is multifarious, its impact on human health is of greatest concern
• Other concerns include impacts on natural ecosystems, effects on weather and climate

Pollutants

• May act as beneficial nutrients in small doses
• This effect of dose or concentration on health is described by a dose-response curve
• For many elements, there is a window of dose beneficial to health, while levels above this window are toxic
• For essential nutrients, concentrations below the beneficial window can lead to deficiency and illness
• Similar dose-response curves exist for plant nutrients

Environmental Toxins

• For many substances, there is a threshold level below which harmful effects are not apparent
• For many environmental toxins, especially carcinogens such as benzene, there is no threshold and any concentration is harmful

Synergism, Acute, and Chronic Effects Of Pollutants

• Extra problems in evaluating the toxic effects of pollutants include additive effects of several pollutants and synergism
• Synergism results in the combined effects of several pollutants producing an effect greater than the sum of the effects of the individual pollutants
• Health effects of pollutants can be classified as acute or chronic
  • Acute: when short-term exposure, usually to high concentrations of pollutants
  • Chronic: when from long-term exposure, usually to lower, ambient levels of pollution

Environmental Standards

• Whether a concentration of a chemical substance is harmful depends on many factors
• The maximum level of a substance that can be allowed without harmful effects is a standard
• The establishment of such standards is a complex and difficult process
• Many standards change frequently as new research sheds more light on pollution and its control
• The tendency is for standard values to decrease
• Most countries specify standards for air pollutants and water pollutants
• These standards are legally enforceable

Two Types of Standards

• Quality
• Emission

Quality Standards

• Refer to the concentration of a pollutant in the environment
• Set concentrations of pollutants in the atmosphere that are not to be exceeded
• Are used to maintain the environmental quality in an unpolluted state
• Are more difficult to enforce

Emission Standards

• Refer to the maximum levels of a pollutant that may be emitted from a pollution source
• Set concentrations of specific pollutants for an industry, that must be below the level

Guidelines

• Are not legally binding
• Are recommended levels of pollutants that, if exceeded, may result in harmful effects
• Environmental standards increase to keep up with industrial production

Job of Environmental Analyst

• Conduct tests for compliance with standards
• If permissible levels are exceeded, technological measures are required to reduce pollutant emissions
• Selection and design of pollution control technology are the job of environmental engineers
• Environmental analysts may be required to assess the efficiency of the control technology and adhere to legislative standards