Chapter 1 Flashcards
Acidity of water is
its quantitative capacity to react with a strong base to a designated pH.
Acidity is a measure of
an aggregate property of water
Acidity is a measure of an aggregate property of water and can be interpreted in terms of
specific substances only
Alkalinity is also known as
the buffering capacity of a stream
alkalinity refers
how well it can neutralize acidic pollution and resist change in PH
alkalinity measures
the amount of alkaline compounds in the water, such as carbonate, bicarbonates and hydroxides. these compounds are natural buffers that can remove excess hydrogen, or H+, ions
BOD means
The Biological Oxygen Demand
BOD means
the amount of oxygen consumed by bacteria in the decomposition of organic material.
BOD also includes
the oxygen required for the oxidation of various chemical in the water, such as sulfides, ferrous iron and ammonia.
dissolved oxygen test tells you
how much oxygen is available
BOD test tells you
how much oxygen is being consumed
BOD is determined by
measuring the dissolved oxygen level in a freshly collected sample and comparing it to the dissolved oxygen level in a sample that was collected at the same time but incubated under specific conditions for a certain number of days.
The difference in the oxygen readings between the two samples in the BOD is recorded in units of
mg/L
Unpolluted, natural waters should have a BOD of
5 mg/L or less
Raw sewage may have BOD levels ranging from
150 – 300 mg/L
conductivity is
a measure of how well water can pass an electrical current. It is an indirect measure of the presence of inorganic dissolved solids such as chloride, nitrate, sulfate, phosphate, sodium, magnesium, calcium, iron and aluminum.
It is an indirect measure of the presence of inorganic dissolved solids such as chloride, nitrate, sulfate, phosphate, sodium, magnesium, calcium, iron and aluminum. The presence of these substances increases
the conductivity of a body of water.
…………………………..like …………………………………………..do not conduct electricity very well, and thus have a ……………….conductivity in water.
Organic substances
oil, alcohol, and sugar
low
Inorganic dissolved solids are essential ingredients for
aquatic life
Inorganic dissolved solids are essential ingredients for aquatic life. They
regulate the flow of water in and out of organisms’ cells and are building blocks of the molecules necessary for life.
A high concentration of dissolved solids, however, can cause
water balance problems for aquatic organisms and decrease dissolved oxygen levels
Temperature: Oxygen is more easily dissolved in
cold water
Flow: Oxygen concentrations vary with
the volume and velocity of water flowing in a stream.
Usually streams with ……………………………………………………. are considered healthy streams.
high dissolved oxygen concentrations (greater than 8 mg/L for Ozark streams)
Usually streams with high dissolved oxygen concentrations (greater than 8 mg/L for Ozark streams) are considered healthy streams. They are able to support a greater
diversity of aquatic organisms
They are able to support a greater diversity of aquatic organisms. They are typified by
cold, clear water, with enough riffles to provide sufficient mixing of atmospheric oxygen into the water.
In streams that have been impacted by any of the above factors, summer is usually the
most crucial time for dissolved oxygen levels because stream flows tend to lessen and water temperatures tend to increase.
In general, DO levels less than ………are stressful to most aquatic organisms.
3 mg/L
Most fish die at
1-2 mg/L
Most fish die at 1-2 mg/L. However, fish can move away from
low DO areas
Water with low DO from ……………………….are considered hypoxic
2 – 0.5 mg/L
waters with ………………………….are anoxic.
less than 0.5 mg/L
Because the temperature of the stream can vary daily, and even hourly, it is important to
factor out the effect of temperature when analyzing the DO levels in a sample of water.
Because the temperature of the stream can vary daily, and even hourly, it is important to factor out the effect of temperature when analyzing the DO levels in a sample of water. This is achieved by
considering the saturation value.
This is achieved by considering the saturation value. Saturation is
the maximum level of DO that would be present in the water at a specific temperature, in the absence of other influences.
Once you know the temperature of the water in your stream you can use an oxygen saturation table to
determine the maximum DO concentration
if your stream temperature is 8 degrees C, your maximum saturation value would be 11.83 mg/L. If your DO reading was 8.5 mg/L, your percent saturation would be
8.50/11.83=71.9 percent
Since a healthy stream is considered to be ………………….percent saturated,
90-100
your sample indicates that something else besides temperature is affecting oxygen levels adversely (examples:………………………………….)
suspended or dissolved solids, or bacteria decomposition
Fecal Coliform
Human and animal wastes carried to stream systems are sources of pathogenic or disease-causing, bacteria and viruses. The disease causing organisms are accompanied by other common types of nonpathogenic bacteria found in animal intestines, such as fecal coliform bacteria, enterococci bacteria, and escherichia coli, or E. coli bacteria.
Fecal coliform, enterococci, and E. coli bacteria are
not usually disease-causing agents themselves.
Fecal coliform, enterococci, and E. coli bacteria are not usually disease-causing agents themselves. However, high concentrations suggest the
presence of disease-causing organisms
Fecal coliform, enterococci, and E. coli bacteria are used as
indicator organisms
ecal coliform, enterococci, and E. coli bacteria are used as indicator organisms; they indicated
the probability of finding pathogenic organisms in a stream.
To measure indicator bacteria
water samples must be collected in sterilized containers. The samples are forced through a filter and incubated at a specific temperature for a certain amount of time. The resulting colonies that form during incubation are counted and recorded as the number of colony producing units per 100 mL of water
Hardness is
frequently used as an assessment of the quality of water supplies. The hardness of a water is governed by the content of calcium and magnesium salts (temporary hardness), largely combined with bicarbonate and carbonate and with sulfates, chlorides, and other anions of mineral acids (permanent hardness)
The effects of metals in water and wastewater range from
beneficial through troublesome to dangerously toxic.
Some metals are essential, others may
adversely affect water consumers, wastewater treatment systems, and receiving waters.
Some metals may be either beneficial or toxic, depending on
concentration
The primary mechanism for toxicity to organisms that live in the water column is by
absorption to or uptake across the gills