Introduction - Elements of Environmental Engineering: Thermodynamics and Kinetics - page 2

of humans for a better life, and is generally increasing as well. The third term on the
right-hand side denotes the extent to which technological advances can be sustained
without serious environmental consequences. The third term can be made as small
as possible to limit the overall environmental impact and enable the transition to a
sustainableenvironment.Bothsocietalandeconomicissuesarepivotalindetermining
whether we can sustain the quality of life while at the same time mitigating the
environmental consequences of the technologies that we adapt.
The quality of our life is inextricably linked to industrial growth and improvements
in agricultural practices. Chemicals are used in both sectors, to sustain innovations in
the industrial sector and to improve agricultural efforts at maintaining a high rate of
crop production. Thus, the chemical manufacturing industry has been at the forefront
of both productivity and growth. During the twentieth century, the chemical manufac-
turing industry has shown phenomenal growth. Overwhelming arrays of chemicals
have been produced each year. Over the whole period of human history, one estimate
suggests that approximately six million chemical compounds have been created, of
whichonly1%areincommercialusetoday.Manyofthecompoundsareimportantfor
sustaining and improving our health and well-being, since they are starting materials
for various products that we use everyday.
1.2 ENVIRONMENTAL STANDARDS AND CRITERIA
There exist several Congressional statutes in the United States that are instrumental
in setting standards for drinking water, ambient water quality, and ambient air quality.
The Environmental Protection Agency (EPA) takes several steps before a stan-
dard is set for a specific compound in a specific environment. These include factors
such as the following: occurrence in the environment; human exposure and risks of
adverse health effects in the general population and sensitive sub-populations; ana-
lytical methods of detection; technical feasibility; and impacts of regulation of water
systems, the economy, and public health.
Environmental quality standards refer to maximum contaminant concentrations
allowed for compounds in different environmental media. These concentrations are
expected to be protective of human health and useful for ecological risk management.
It has long been recognized that a realistic assessment of the effects of chemicals
on humans and ecosystems is mandatory for setting environmental quality standards.
The implication is that our concerns for the environment should be driven by sound
science. A prudent policy with regard to environmental regulations should con-
sider the weight of evidence in favor of acceptable risk against potential benefits.
In fact, risk assessment should be the paradigm that is the basis for current and future
environmental legislation.
1.3 THE DISCIPLINE OF ENVIRONMENTAL ENGINEERING
Environmental awareness is the first step in understanding pollution problems. On the
one hand, we should better understand the potential impacts, so that we can focus our
resources on the most serious problems. On the other hand, we should also understand