Faster Dissolved Oxygen Test Kit


The purpose of my project is to determine if there is any significant
difference in dissolved oxygen (DO) levels as measured by the traditional HACH?
method or the newly developed CHEMets? test kit under typical field conditions.


My hypothesis is that there is no significant difference in dissolved
oxygen (DO) levels as measured by the traditional HACH? method or the newly
developed CHEMets? test kit under typical field conditions.

Review of Literature

"Ours is a watery world, and we, its dominant species, are walking sacks
of sea water. The presence of large amounts of liquid water on Earth make our
planet unique in the solar system." (Hill, 1992 p. 477)
People have recently become more concerned with preserving our earth for
future generations. Even the government pitches in to help save our earth by
enacting laws to help preserve our natural resources. There is local evidence
that improved sewage treatment means improvement in water quality. Monitoring on
a national level showed that large investments in point-source pollution control
have yielded no statistically significant pattern of improvement in dissolved
oxygen levels in water in the last 15 years. It may be that we are only keeping
up with the amount of pollution we are producing. (Knopman, 1993)
The early biosphere was not pleasant for life because the atmosphere had
low levels of oxygen. Photosynthetic bacteria consumed carbon dioxide and
produced simple sugars and oxygen which created the oxygen abundant atmosphere
in which more advanced life forms could develop. (Brown, 1994) The mystery of
how Earth's oxygen levels rose is very complex. Scientists don't agree when or
how the oxygen on earth got here, but we know we could not live without it.
(Pendick, 1993) Oxygen is crucial for humans to survive. Dissolved oxygen is
also crucial for most fish and aquatic organisms to survive. Dissolved oxygen
is for them what atmospheric oxygen is for humans. If humans have no oxygen to
breathe, they die. The same goes for fish. However, fish get their oxygen from
the water, and humans get theirs from the atmosphere. (Mitchell and Stapp,
Different aquatic organisms need different levels of dissolved oxygen to
thrive. For example, pike and trout need medium to high levels of dissolved
oxygen. Carp and catfish are the exact opposite, needing only low levels of
dissolved oxygen. (Mitchell and Stapp, 1992 ) Low levels of dissolved oxygen
inhibit the growth of Asiatic clams. ( Belanger, 1991) In the American River,
too much dissolved oxygen resulted in mortality of salmonoid fishes. (Colt,
Orwicz and Brooks, 1991) Brood catfish, or catfish raised on fish farms, are
especially susceptible to low dissolved oxygen. Since catfish are a major food
source for many people, their production is important. (Avault, 1993)
There are two main sources of dissolved oxygen: (1) the atmosphere -
waves on lakes, rapidly moving rivers, and tumbling rivers all act to mix oxygen
from the atmosphere with water; (2) aquatic plants - algae and benthic plants
(bottom-rooted plants) deliver oxygen into the water through photosynthesis.
The solubility of all gases, including oxygen, is inversely proportional
to temperature which means that the solubility of gases goes down as the
temperature goes up, and vice versa. The concentration of dissolved oxygen also
varies directly with atmospheric pressure and atmospheric oxygen concentration.
When the atmospheric pressure or atmospheric oxygen concentration goes up, the
level of dissolved oxygen goes up. (Roskowski & Marshall, 1993) D.H. Farmer
studied the fluctuation of dissolved oxygen content in a body of water before,
during, and after a storm. During the storm, the increased wave activity
increased the dissolved oxygen content. (Farmer and McNeil, 1993)
Turbulent flow in streams has caused most of the biocenogenesis (the
environmentally determined characteristics of an organisms) to be represented by
attached or benthic organisms. For this reason, a method of evaluating the role
of benthic organisms in the total dissolved oxygen balance was created. Benthic
plants play an important role in providing dissolved oxygen. These plants
respire oxygen through photosynthesis. Benthic plants are plants such as
cattail, bulrush, arrowhead, water lily, pond weeds, and muskgrass. (Nebel,
Many things can change the level of dissolved oxygen in a body of water.
Dissolved oxygen levels rise from morning through afternoon as a result of
photosynthesis. Photosynthesis stops at night, but animals and plants continue
to respire and consume oxygen. Water temperature and volume of water also
affect dissolved oxygen levels. Dry weather causes dissolved oxygen levels to
decrease and wet weather causes dissolved oxygen levels to increase. (Mitchell
and Stapp, 1990)
The breakdown of organic matter by bacteria decreases dissolved oxygen
in the water and yet enriches the water with plant nutrients. A reasonable
amount of breakdown is good, so the water won't become oligotrophic or nutrient
poor. But too much organic