Water Quality Index Scale
91-100:
Excellent water quality
71-90:
Good water quality
51-70:
Medium or average water quality
26-50:
Fair water quality
0-25:
Poor water quality
Fecal Coliform Bacteria Test
Fecal Coliform Bacteria are naturally
present in the human digestive track. This
bacteria should be rare or absent in
“unpolluted” waters. Coliform bateria
should not be found in sources of drinking
water. Their presence in water serves as a
reliable indication of sewage or fecal
contamination. Less than 1000 bacteria
colonies per 100 mL of water is acceptable
by the government for waters used for
swimming purposes, while less than 5000
BC/100mL are allowed for waters used for
boating or fishing. This test will indicate
if your sample has above or below 200
BC/100mL, thus indicating if fecal matter
has contaminated your sample.
Directions:
1.
Since this test requires a 48-hour
incubation period, all the water samples
have already been tested earlier this
week.
2.
Find the vial labeled with the same
letter as your beaker.
3.
Compare the color of the fluid inside
the beaker to the Coliform color chart.
4.
If your result is Negative your Qvalue is 100; if positive, your Q-value
is 65.
Dissolved Oxygen Test
This test measures the amount of oxygen
dissolved in the water. Dissolved oxygen
(DO) is important to the health of aquatic
ecosystems because all aquatic organisms
need oxygen to survive. The DO in water is
available to fish, invertebrates, and
aquatic plants. If the levels are low, then
the organisms might drown. Low levels of DO
in water are signs of possible pollution.
The percent saturation of dissolved oxygen
in water is an important measurement of
water quality. Cold water can hold more DO
than warm water; therefore, the temperature
of the water must be accounted for.
Directions:
1.
Record the temperature of your water
sample.
2.
Fill the small tube all the way to
the top with water from your sample.
3.
Drop 2 DO test tablets into the small
tube. It’s ok if some of the water
overflows. If water does not overflow,
you do not have enough water in your
tube!
4.
Screw the cap on the tube. More
water will overflow as the cap is
tightened. Make sure that there are no
air bubbles in the sample.
5.
Mix/shake the tube until the tablets
disintegrate.
6.
Wait 5 minutes for the color to
develop.
7.
Compare the color of your sample to
the DO color chart. This will give you
the ppm DO in your sample.
8.
Look at the % Saturation Chart. Use
the temperature and the ppm DO of your
sample to determine its % saturation.
9.
Now, determine and record the Q-value
using the 2nd Chart provided.
Nitrate Test
Nitrate is a nutrient needed by all aquatic
plants and animals to build protein. It is
a measure of the oxidized form of nitrogen.
The decomposition of plants and animals, as
well as the excretions from living animals
can release nitrates into the aquatic
system. An excess of this nutrient can
plant grow and decay and promote bacterial
decomposition, all of which can decrease the
amount of oxygen available in the water.
Sewage is the main source of excess nitrate
added to the water. Fertilizers and
agricultural runoff also contribute high
levels of nitrate.
Nitrates can be harmful to humans because it
affects the ability of our red blood cells
to carry oxygen. This is especially true
for infants or people with already weak
immune systems.
Directions:
1.
Fill the test tube to the 5mL line
with your water sample.
2.
Add 1 nitrate test tab.
3.
Cap tube and mix until the tab has
dissolved.
4.
Wait 5 minutes for the color to
develop.
5.
Compare the color of the sample to
the Nitrate Color Chart (if no color
develops at all, the result is 0ppm).
Record the ppm Nitrate.
6.
Determine the nitrate Q-value of your
sample.
ppm Nitrate
0
5
20
40
Q-value
98
95
73
36
Phosphate Test
Phosphate is a nutrient needed for plant
growth and animal growth. It is also a
fundamental element in metabolic reactions.
High levels of this nutrient can lead to the
overgrowth of plants, increased bacterial
activity, and decreased oxygen levels.
Phosphate comes from several sources,
including human and animal waste, industrial
pollution, and agricultural runoff. Phosphates can be present in the water in many
forms, so this test will give an estimate of
the total amount of phosphate potentially
available in a given water supply.
Directions:
1.
Fill the test tube to the 10 mL line
with your water sample.
2.
Add 1 phosphorus test tablet.
3.
Cap and mix tube until the tablet has
dissolved.
4.
Wait 5 minutes for the blue color to
develop.
5.
Compare the sample to the phosphate
color chart (if no color develops at all,
the result is 0ppm). Record the ppm
Phosphate.
6.
Determine the nitrate Q-value of your
sample.
ppm Phosphate
Q-value
0
98
1
92
2
37
4
14
pH Test
pH is a measurement of the acidic or basis
quality of water. Most forms of aquatic
life tend to be very sensitive to changes
in pH. These organisms are highly adapted
to a specific pH level and may die if the
pH of water changes even slightly.
The pH of natural water is usually between
6.5 and 8.2. The pH of seawater is usually
between 7.8 and 8.4.
Directions:
1.
Turn on palm and open up the Imagi
Probe Software.
2.
Make sure it is on Investigation 4
3.
Press New Trial and make sure the
sensor is set to test pH.
4.
Rinse probe with Distilled water from
Squeeze bottle and wipe dry with a Kim
Wipe. Place probe in sample.
5.
Press Preview on Palm, then press
Collect
6.
The probe will collect 5 pH readings
during one minute and display them (the
red numbers in the upper left). Record
the 5 pH readings on your data sheet.
Take the average and record this as the
pH reading for your sample.
7.
On the Palm, press Stop, Cancel, and
then Delete to prepare the probe for the
next group.
8.
Compare to the pH Water Quality
Values chart to determine the Q-value for
your sample.
pH Water Quality Values
PH
<2.0
2.0
3.0
4.0
5.0
6.0
7.0
7.5
8.0
9.0
10.0
11.0
12.0
>12.0
Q-value
0
2
4
8
24
55
90
92
85
50
50
22
7
2
Percent Saturated Dissolved Oxygen
Temp
oC
(unbolded numbers are the %
saturation for the associated ppm
Dissolved Oxygen ppm
and Temp)
0 ppm
4 ppm
2
0
29
4
0
31
6
0
32
8
0
34
10
0
35
12
0
37
14
0
39
16
0
41
18
0
42
20
0
44
22
0
46
24
0
48
26
0
49
28
0
51
30
0
53
8 ppm
58
61
64
68
71
74
78
81
84
88
92
95
99
102
106
% Saturated DO Water Quality Values
% Saturation
0
30
40
50
60
70
80
90
100
110
Q-value
0
20
30
43
56
77
88
95
100
95
Water Quality Index Data Sheet
Circle letter of your sample:
A
B
C
D
E
Group Members:
Test
Parameter
Test Results
Q-value
Total
Weighing
Quality
Factor*
Index
Temperature:
Dissolved
ppm DO:
Oxygen
% Saturation:
Positive
Fecal
Coliform Negative
0.27
0.25
Nitrates ppm Nitrate:
0.16
Phosphates ppm Phosphate:
0.16
pH
pH1:
pH2:
pH3:
pH4:
pH5:
Average pH:
0.17
*The weighing factor indicates the importance of each parameter to the
overall water quality. The parameters with higher weighing factors are
considered more important in determining water quality than the ones
Circle the Water Quality
with smaller factors.
of
this sample based on index
Overall Water Quality Index:_______
(Sum up values in last column) (use scale):
Guess where your sample came from:
Actual Location Where Sample Taken:
Excellent
Good
Medium/Average
Fair
Poor
(Ask mentor)