Lesson 84: Perspectives on Water Pollution
In this lesson, we will learn about dead zones and eutrophication. Then, we
will discuss the federal government's efforts to control water pollution
through the Clean Water Act. We will also talk about the importance of
sanitation and look at some common forms of water pollution. Finally, we will
look at standards established by the EPA to maintain water quality.
A dead zone is an area lacking oxygen. All oxygen-breathing animals cannot
survive in such an area. The impact of nitrogen flowing into the Gulf of Mexico
in 1974 created a dead zone. Dead zones can occur in the water or on land. This
issue got national attention since the gulf fishery accounts for $2.8 billion
annually in commerce.
Nitrogen promoted the growth of phytoplankton and
harmful algae blooms. Nitrogen had leached into the water from
agricultural run off.
Eutrophication is the process of enrichment by nutrients. Vital water resources
like in the Gulf of Mexico example, cannot receive pollutants like nitrogen and
be expected to continue to deliver the same bounty of goods and services.
After the Cuyahoga River in Cleveland, OH caught fire in
1969 because of industrial pollution, people were outraged and public debate
ensued. This led to the passage of the Clean Water Act of 1972 (CWA) to restore
and maintain national waters.
The EPA is in charge of administering the CWA. The CWA has been far reaching and
effective legislation.
There are
two sources of water pollution- point and non-point. Point sources include
run-off from factories, sewage systems, oil and coal use. This can be
identified and traced easily.
Non-point sources occur from city streets,
suburbs and animal feedlots. These sources are less easy to
identify and see immediately.
Pathogens are
disease-causing bacteria, virus and parasites. Pathogens enter water through
contamination. They can infect human beings through contaminated food, water
and exposure to fecal waste.
Sanitation is essential for health. Public health efforts to
improve sanitation include the purification of water, collection of human and
animal waste, maintenance of sanitary standards and education in hygiene
practices. Sanitation is good medicine and considered more important than
modern medicine in controlling waterborne diseases.
In 2012, 780 million people did not have safe drinking water and
2.8 billion people lived in areas without good sewage collection or treatment.
Human and animal organic wastes can cause serious problems if they enter the
water untreated. This can be a huge problem if not addressed and leads to poor
hygiene and sickness.
Biochemical oxygen demand (BOD) measures how much organic material is in
the water. The higher the BOD, the greater the likelihood that
oxygen will be depleted while breaking down organic matter.
Chemical pollutants linger in
the water. They include petroleum products, heavy metals such as lead, mercury
and arsenic, acids, and road salts. When acidic water from mines containing
sulfides and iron enter natural water streams, they turn them orange and brown
and render them sterile, killing off all natural life.
The EPA formulated a list of criteria pollutants. These are 167 chemicals
listed by the EPA that are toxic. Lower levels of some these pollutants are
considered acceptable.
In 1974, the EPA established Drinking Water Standards and
listed 94 contaminants that could not be allowed in the water.
Two other water quality criteria in
use are
the NPDES and TMDL. The National Pollution Discharge Elimination System (NPDES)
addresses point-source pollution and issues permits that regulates discharges
from industrial power plants. The Total Maximum Daily Load (TMDL) program
evaluates all pollutants entering the water.