33
D. Kar, Wetlands and Lakes of the World,
DOI 10.1007/978-81-322-1023-8_3, © Springer India 2013
Water is a basic substance on which the dynamics
of a water body and thereby the life of the biota in
it depends. To a limnologist, fishery scientist and
a fish farmer, the study of water is a prerequisite
for the welfare of the water body and the fishes
and to know their environment. Further, agencies
like Public Health Engineering Department
(Water Works), Pollution Control Board and various
industrial organisations require to analyse water/
wastewater samples. The methodology recommended by APHA (1995) is largely followed and
are given below.
The main purposes of physical and chemical
examination of water are as follows:
(a) To know the exact composition of the sample
at the particular point of time of sample
collection
(b) To classify water with regard to the general
level of gaseous and mineral constituents
(c) To ascertain the presence or absence of constituents affecting various beneficial uses of
water
(d) To determine the level of organic impurities
(e) To determine the degree of clarity and to
ascertain the nature of matter in suspension
After the analyses are over, the results may be
interpreted to suit different purposes for different
organisations (according to the aim of the work),
e.g. surveillance of water quality, effluent quality
and farming.
Among the physico-chemical characteristics,
the following parameters are generally studied in
a water body by a limnologist:
3.1
Physical
Temperature, turbidity and transparency.
3.1.1 Temperature
In limnological studies, water temperature, as a
function of depth, is often required. Water temperature readings are related to the study of pH,
dissolved oxygen, salinity, conductivity, etc.
However, heated-water discharges into the water
body generally have detrimental effects.
3.1.1.1 Principle
Water temperature could be measured with the
help of good-quality mercury-in-glass precision
thermometer (−5 to 50 × 1/10 °C) having minimal
thermal capacity to facilitate rapid equilibration.
It could be checked and calibrated (if required)
against a precision thermometer certified by the
National Bureau of Standards (ordinary thermometers may have errors up to 3 °C).
Temperature of both air and surface water
could be measured directly. However, bottom
water temperature could be measured by collecting the water samples from various depths
with the help of a 5-l capacity Kemmerer sampler. Alternatively, water temperature at depths
may be most conveniently and accurately measured with the help of a thermistor or with the
help of a less-expensive reversing thermometer
or thermophone.
3
Lentic Water (Physico-chemical
Characteristics of Water)
D. Kar, Wetlands and Lakes of the World,
DOI 10.1007/978-81-322-1023-8_3, © Springer India 2013
Water is a basic substance on which the dynamics
of a water body and thereby the life of the biota in
it depends. To a limnologist, fishery scientist and
a fish farmer, the study of water is a prerequisite
for the welfare of the water body and the fishes
and to know their environment. Further, agencies
like Public Health Engineering Department
(Water Works), Pollution Control Board and various
industrial organisations require to analyse water/
wastewater samples. The methodology recommended by APHA (1995) is largely followed and
are given below.
The main purposes of physical and chemical
examination of water are as follows:
(a) To know the exact composition of the sample
at the particular point of time of sample
collection
(b) To classify water with regard to the general
level of gaseous and mineral constituents
(c) To ascertain the presence or absence of constituents affecting various beneficial uses of
water
(d) To determine the level of organic impurities
(e) To determine the degree of clarity and to
ascertain the nature of matter in suspension
After the analyses are over, the results may be
interpreted to suit different purposes for different
organisations (according to the aim of the work),
e.g. surveillance of water quality, effluent quality
and farming.
Among the physico-chemical characteristics,
the following parameters are generally studied in
a water body by a limnologist:
3.1
Physical
Temperature, turbidity and transparency.
3.1.1 Temperature
In limnological studies, water temperature, as a
function of depth, is often required. Water temperature readings are related to the study of pH,
dissolved oxygen, salinity, conductivity, etc.
However, heated-water discharges into the water
body generally have detrimental effects.
3.1.1.1 Principle
Water temperature could be measured with the
help of good-quality mercury-in-glass precision
thermometer (−5 to 50 × 1/10 °C) having minimal
thermal capacity to facilitate rapid equilibration.
It could be checked and calibrated (if required)
against a precision thermometer certified by the
National Bureau of Standards (ordinary thermometers may have errors up to 3 °C).
Temperature of both air and surface water
could be measured directly. However, bottom
water temperature could be measured by collecting the water samples from various depths
with the help of a 5-l capacity Kemmerer sampler. Alternatively, water temperature at depths
may be most conveniently and accurately measured with the help of a thermistor or with the
help of a less-expensive reversing thermometer
or thermophone.
3
Lentic Water (Physico-chemical
Characteristics of Water)