Objective 5

Objective Five: To understand environmental impact, environmental change, and pollution.

This course is concerned with the interactions between the sociosphere and the earth's four natural systems. These interactions frequently results in impacts of the earth's natural physical environment. We know that humans have impacted the environment for a long time. Some of this impact is deliberate. Clearing a grassland to plant crops is a deliberate alteration of the environment and if the decision is whether to have food to eat or starve, or alter the natural environment, this is a pretty easy decision for most, if not all, humans to make. However, at the same time, there may be unintended environmental impacts with clearing fields. Depending of the slope of the ground, valuable topsoil may runoff into nearby waterways, thereby over time making the field less productive for food and possibly choking waterways with sediment.

There is a formula used for estimating or calculating the level of environmental impact. Environmental impact is a function of three things.

Number One - The population or number of people utilizing the natural environmental or resources. The more people there are in a place, the more likely that environmental impact will occur.

Number Two - The greater the level of consumption of natural resources -- such as water, energy, minerals, land, rocks and trees - the greater the likely environmental impact.

Number Three - The type of tools, techniques, processes, or technologies used by humans to provide a service or material good also effects the level of environmental impact.

While this formula is simplistic, it is nonetheless a valuable tool for understanding the relationship human activity and environmental impact.

There are different levels and types of environmental impact, many of which will be covered over the course of the semester. There are, however, two major categories of environmental impact, environmental change and pollution.

Environmental change refers to the unintended consequences of human activity that result in a change or alteration of the natural environment. For example, clearing a grassland to plant crops, as discussed in section 5.0, is a deliberate change of the natural environment. If the same crops, however, are planted in that field year after year, that plot of ground will lose many of its nutrients. This loss of nutrients is considered to be unintended change. If techniques are not used to control soil erosion, valuable topsoil may runoff the field, another unintended environmental change.

Nature, however, operates in such a way so that natural systems can be used and will replenish themselves as long as they are not over-utilized. If that same field is left fallow, or unused, for a period of time, the nutrients may be restored. Leaving the field unused for a longer period of time, may help to replenish some of the topsoil lost. Irreversible environmental changes can result, however, if the land is continuously over-utilized, by human activity, thereby leaving the field worthless to humans to produce food as well as permanently altering the chemical or structural composition of the soil. The difficult part is finding the right balance to use the field in such a way without permanently altering its' natural components as well as providing a long term food. This type of approach is known as a "sustainable" approach.

Over-utilization of natural systems, that is to say, not using them in a sustainable way, is not the only manner in which humans can impact the natural environment. The other way in which humans impact the environment is pollution. Pollution refers to unwanted solid, liquid, or gaseous chemicals produced as by-products or wastes when a resource is extracted, processed, made into products or used. Pollutants don't always have to be chemical in nature. Pollution can also take the form of excessive heat, noise, light, or radiation.

Pollutants can enter the environment naturally. Volcanic ash, for example, can be viewed as a "natural" pollutant. Most natural pollution, however, is dispersed over a large area and is often diluted or broken down to harmless levels by natural processes. In contrast, human generated, or anthropogenic pollution tends to occur where there are lots of humans, such as in or near industrial areas where large volumes of pollutants are concentrated in small volumes of air, water, and soil. Some pollutants contaminate the areas where they are produced. Others are carried by wind or flowing water far away from their original sources.

Some environmental pollutants come from single, identifiable sources, such as a smokestack or sewer pipe. These are referred to as point sources of pollution, because they come from a single point or location.

Other pollutants enter the air, water, or soil from dispersed sources called non-point sources. Examples of non point sources include automobile exhaust, runoff of fertilizers and pesticides from lawns and farms, and the flow of various sorts of chemicals and oil from urban streets and parking lots into nearby rivers and streams.

Three factors determine how severe the effects of a pollutant will be. They include:

There are three ways in which humans deal with pollution. Remember we stated, that pollution is the unwanted solid, liquid, or gaseous chemicals produced as by-products or wastes, though pollution can also refer to excessive heat, noise, light, or radiation.

The first way humans deal with pollution is to create pollution, release it into the environment, and then, at some point, decide to clean it up. This is known as pollution remediation. Remediation of pollution can be extremely costly because materials or chemicals are initially paid for and wasted and because removing pollution from natural systems can be very expensive.

The second way in which deal with pollution is to create it, and then capture or change its' form, before releasing the remaining liquid, material or chemicals into the environment. This is known as pollution control. Pollution control technologies include the catalytic converter on your car and the carbon activated water filter on your sink.

The third and final way in which humans have learned to deal with pollution is pollution prevention. Pollution prevention refers to providing the desired service or material good without creating the pollution in the first place. An example of pollution prevention would be switching to a organic, citrus based cleaner for your kitchen sink or bathroom instead of using a caustic chemical. Of the three ways in which humans deal with pollution -- remediation, control and prevention, pollution prevention has emerged as the most preferred as well as often the least expensive.

The Community College of Baltimore County
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Catonsville, MD 21228

EI =	Population X	Consumption X	Technology
Env. Impact	(Number of People)	(Amount of Resources Consumed)	(Tools or Techniques Used)