Lecture 2 Environmental Issues

1. Lecture 2Environmental Issues

2. Environmental Issues • Factors that affect environment and may cause environmental instability in the long run • Affect every part of our life • Overpopulation, climate change, conservation, biodiversity, water quality, groundwater contamination , soil contamination, natural resourcesdepletion, waste management,sustainable development, nuclear issues, energy, disaster reduction, air pollution, noise pollution, poverty • All these issues are interconnected and growing exponentially

3. We are increasingly becoming an urban species (large number & use of technology) and our effects on the environment are more and more of the effects of urban life As urban areas expand, wetlands are filled in, forests cut, and soils covered over and removed from productive use An urban world

4. Values and Knowledge • Values and knowledge are central to our understanding of environmental science • Knowledge tells us what solutions are possible • What we ultimately decide to do—which of the possible solutions we choose—depends on our values, i.e., how we value the environment

5. Pollution and Pollutants • Any undesirable change in the characteristics of air, water, soil and food that can adversely affect health, survival, or activities of human or other living organisms • A pollutant is a chemical or material out of place or present at higher than normal concentrations that has adverse effects on organisms • Pollutants can enter the environment naturally or through anthropogenic activities

6. Unwanted effects of pollutants • Almost every part of the human body is affected by one pollutant or another • Lead and mercury affect the brain, arsenic the skin, carbon monoxide the lungs, and cadmium the heart • However, a toxin that affects the brain, such as mercury, causes a variety of other problems as well • Unwanted effects include • Disruption of life support systems for humans and other species • Damage to wildlife, human health, property • Nuisance such as noise, unpleasant smells, tastes, and sights

7. Factors determining the severity of the pollutants • Type and nature of the pollutant (organic or inorganic, ionized or nonionized, solubility whether in water or fat) • Concentration • pH, Eh • Temperature, Wind, Persistence, Chemical forms, Volatility, Biodegradability, Water quality, Organic matter content, Soil properties, and many more • Bioaccumulation • Biomagnification • Chemical interactions (antagonistic or synergistic)

8. Resources • Anything obtained from the environment to meet human needs and wants • Three types—perpetual, renewable, nonrenewable • Solar energy is called a perpetual resource because on a human time scale it is renewed continuously • It is expected to last at least 6 billion years as the Sun completes its life cycle

9. Resources • Renewable resource can be replenished through natural processes as long as it is not used up faster than it is replenished, e.g., forests, fresh water, air, fertile soil, etc • Nonrenewable resources are in limited supplies and are depleted by use • Do not replenish within a reasonable period of time on the human time scale, e.g., Fossil fuels

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