Review: Conservation of Matter• Matter cannot be created or destroyed it can only change form – The amount of matter in the universe is finite (unchanging) – Atoms (of certain elements) are recycled over and over again. – 92 naturally occurring elements make up nearly all matter. – Go through innumerable chemical reactions to both form and breakdown compounds. – For example some of the atoms that now make up your body may have once been part of a dinosaur, a rock, a tree, and a panda bear at one point in their existence.
Review: Biogeochemical Cycle • Bio = Biosphere (Living Things) • Geo = Geosphere (Rocks / Earth) • Chem= Chemical Factors • Biogeochemical Cycles: Track the repeating movement of atoms and energy through both the living and nonliving parts of the earth system. • Biogeochemical Cycles are the basis for nutrient recycling and support all life on earth!
Factors Affecting Cycles: Consumption• Consumption: The rate at which a particular resource is being used.• Recharge Rate: The rate at which a particular resource is replenished by the biogeochemical cycle.• Sustainable Use: When consumption is the same, or lower, than recharge rate. Can be maintained indefinitely. – Renewable Resource: A resource that can be used sustainably. Usually recharge quickly.• Mining (Over Consumption): When the rate of consumption for particular resource exceeds the recharge rate. Tap into stored reserves (reservoirs) that will eventually run out. – Non-Renewable Resource: A resource that is not used sustainably. Usually recharge very slowly.
Water Consumption• We’ve looked in depth at water consumption, in short most of the world’s water supply is not being sustainably managed.• This is important because we have a very limited supply of fresh water.• Excessive consumption is only half the problem however....
Pollution • The EPA defines pollution as the “presence of a substance in the environment that, because of its chemical composition or quantity, prevents the functioning of natural processes and produces undesirable environmental and health effects.” • Pollution: The contamination of air, water, or soil by substances that are harmful to living organisms and ecosystems. • Pollutant: Any substance that causes pollution.
Pollution is a Major Problem!• Contamination further reduces the limited amount of resources available for human use.• Water pollution for example renders much of, the already small amount, of the earth’s total fresh water unsafe for human consumption. – Water requires costly treatment and filtration before use.
Types of Water Pollution• Pollution can come from natural sources, such as volcanic eruptions, or from human actions, such as disposal of industrial waste.• There are 3 main types of water pollution that render fresh water unfit for human use: – Inorganic Pollutants: (Ex. Heavy Metals like Lead) • Chemical (Ex. Benzene) • Physical (Ex. Non-Biodegradable Materials like Plastic) – Organic Pollutants: (Ex. Fertilizer and Sewage) – Biologic Pollutants: (Ex. Bacteria and Viruses)• Heat and Sediment Load can also be a dangerous pollutants for aquatic organisms.
Natural Sources of Pollution• There are many naturally occurring pollution sources. - Sulfur springs - Oil Seeps - Sedimentation - Volcanoes• These pollution sources, however, have been around for millions of years. - Ecosystems have evolved to accommodate them. - Therefore, they represent less of a threat than anthropogenic sources.
Anthropogenic Sources of Pollution The Impact of Human Activity
Point vs. Non-Point Sources of Pollutants:• Point Sources involve the discharge of substances from specific areassuch as factories, sewage systems, power plants, underground coal mines, and oil wells.• Non-Point Sources are poorly defined and scattered over broad areas. Pollution occurs as rainfall and snowmelt move over and through the ground, picking up pollutants as they go. (agriculture runoff, storm-water drainage, and atmospheric deposition)
Point Sources:• Discharge from specific location directly into waterway o Drain pipes, sewer outlets, chemical spills.• Can be traced back to the source and dealt with. – Often use aerial or satellite imagery. – Trace concentration levels upstream.• Some sources are mobile.
Non-Point Sources• Runoff of pollutants into waterway• Farm runoff, feedlots, golf courses, lawns• Construction sites, logging areas, roads, parking lots.• Much more difficult to manage because they are diffuse (spread out).
What is a Physical Pollutant?• Physical or Macroscopic Pollution refers to pollutants that are large enough to be seen with the naked eye. – large visible items polluting the water. – Generally refers to human “garbage”. • Plastic is the most common
Plastic• Man-made from petroleum, produced through complex (and often dangerous) chemical processes.• The first fully synthetic plastic, Bakelite, was introduced by Belgian Chemist Leo Baekeland in the early 1900s.• Development of Modern Plastics• Today plastics have innumerable uses. – Over 100 million tons produced in the US per year.
Pros vs. Cons• Pro: – Easy to produce – Cheap – Malleable – Waterproof and Durable • Makes a good container• Con: – Not biodegradable. – Hard to recycle. • Costs more to recycle a plastic bag than to make a new one. – Production releases dangerous chemical pollutants. – Not very cheap when you factor in disposal costs. – Becomes dangerous pollutant.
Problems With Plastic• The vast majority of plastics are not biodegradable. – They cannot be broken down by the environment. – Stays in environment forever.• Despite the fact that the plastic itself endures for long periods of time most plastic products are treated as single use disposable items.• Less than 1% of the total plastic produced each year is recycled. – Americans throw away 2.5 million plastic bottles every hour.
Once this plastic is released into the environment it becomes a dangerous pollutant....