||The amount of molecular oxygen dissolved in water is an important measure
of habitat availability for aquatic organisms. Low levels of oxygen result
from the introduction of organic waste pollution which increases the rate
and decreases the suitability for aquatic animal life. Sources include:
agricultural runoff, urban runoff, and wastewater treatment plants.
||pH is a unit that expresses the strength of a solution based on its
acidic or basic properties. Aquatic organisms can only function in a particular
range of pH, and become forced to relocate when the surrounding water changes.
Pollution from burning fossil fuels increases the amounts of sulfur and
introduced into the water, thereby increasing the overall acidity.
||The amount of suspended material in water can be measured by collecting
the solids or assessing the relative light transmission of the suspension.
The increased opaqueness is caused by increased sediment
which negatively affect many aquatic organisms. Both algal production and
fish reproduction and feeding can become diminished and some organisms,
like shell-fish (continual filter-feeders) can become choked by sediment
and eventually die in heavily turbid waters.
||There are many chemicals that have the capacity to travel throughout
a waterway. Many of these are pollutants and can cause significant distress
to the surrounding habitat. Solutions such as oil or antifreeze enter a
watershed from nearby runoff
sources and directly poison the surrounding aquatic environment. With appropriate
riparian vegetation, large surge concentrations of these chemicals can
be prevented from directly entering the water.
||Industrial effluents are major sources of heavy metals, and aquatic
environments are extremely sensitive to even the smallest concentrations
of these materials. Serious abnormalities have been reported in many aquatic
organisms. Arsenic and mercury are two common examples of heavy metals,
but other similar substances and compounds can also have significant effects
on an aquatic community.
||Additional nutrients, such as phosphorus and nitrogen, are added to
streams by many avenues, but primarily through human sewage, animal waste,
fertilizers and erosion. This area of water quality monitoring is greatly
affected by both urban and agricultural human practices. Runoff from any
inadequately covered lands can increase these nutrient loads and result
in eutrophication of the nearby aquatic habitat.