Environmental Geology
Environmental Geology

Chapter 16
Chapter 16
Water Pollution

Overview
Overview
•
General Principles
•
Industrial Pollution
•
Organic Matter
•
Agricultural Pollution
•
Reversing the Damage–Surface Water

Overview (cont.)
Overview (cont.)
•
Groundwater Pollution
•
Reversing the Damage–Ground Water

General Principles
General Principles
•
•
Most often, human activities increase the
rate-of-influx term, either by dumping of
concentrated wastes or through
accelerated weathering, as of mine
tailings.

Industrial Pollution
Industrial Pollution
•
Inorganic Pollutants–Metals
•
Other Inorganic Pollutants
•
Organic Compounds
•
Problems of Control
•
Thermal Pollution

Heavy Metals
What characteristic of the so-called heavy
metals causes them to be especially
hazardous to humans and other animals
high in food chains?
•
The heavy metals accumulate in the body;
they are not readily excreted. Therefore,

The main problem is that there are so many
synthetic organics and that we know so little
about the toxicity of the vast majority of
them. (It has also been discovered that
many are toxic in very low concentrations
and are persistent in the environment.)

Detection of Pesticides in Urban & Ag Areas
Figure 16.6A
16-5
Source: USGS Pesticides National Synthesis Project, 2000.

BOD (biochemical oxygen demand)
•
BOD, or biochemical oxygen demand, is the
amount of oxygen that would be required to break
down the organic matter in the water aerobically.
The higher the BOD, the lower the dissolved
oxygen concentration tends to be. Just below an
organic-waste source, there will be a drop (“sag”)
in dissolved-oxygen concentration, reflecting
increased BOD. Oxygen levels will be restored
downstream through reaeration and waste decay.