Groundwater is one of the most widely distributed resources of earth and is also
an essential source of drinking and irrigation water in Bangladesh. It is also considered
as one of the most important resources because of the physiological needs of man,
animals, plants, stream, navigation, fisheries, salinity control, dilution of pollution and
water required for ecological protection and wetland preservation. So the quality of
groundwater is as important as is its quantity. All groundwater contains salts in solution that
are derived from the location and past movement of the water. The quality required of
a groundwater supply depends on its purpose; thus, needs for drinking water,
industrial water, and irrigation water vary widely.
The field parameters of water quality, hydrochemical analysis for 25 parameters
of groundwater, suitability of the shallow tube well water for domestic, industrial and
irrigation use, and comparison of analytical results with national and international standards
for drinking and irrigation purpose are the main objectives of this study.
A total of six samples of groundwater from six Shallow Tube Wells (STW) of one
each upazilla were collected in clean plastic bottles (500) at different sections in dry
season. Before collecting the samples, each well was pumped for 10 min and then two
water samples were collected in a new plastic bottle of 500 mL capacity, which was
immediately airtightened with stopper tops to protect air bubbles from forming inside. One of
the samples was treated with Hydrochloric Acid (HCl) up to the achievement of pH value
of 4.0 to avoid any sort of precipitation of the dissolved ions. All samples were stored in
a refrigerator. The field parameters, such as Temperature, pH, Redox potential (Eh),
Specific Electrical Conductance (SEC), alkalinity and Dissolved Oxygen (DO),
were determined during fieldwork by portable instruments. Temperature was measured in the field
using a Scientific Thermometer. pH and Eh were measured by using Bench Meter (Hanna
pH 211, Portugal). SEC was measured using EC Meter (Lutron CD 4301, Japan). The
Arsenic concentrations were investigated using field test kit during
work. To carry out a detailed hydrochemical analysis for major parameters such as
Ca2+, Mg2+, Na+,
K+, Cl_,
CO32_,
HCO_3,
SO42_,
NO3_,
NO2_,
NH4_, Fetotal,
Mn2+, B+, F_,
I_, PO42_, DO, TDS and SAR, water
samples from 6 DTWs were selected on the basis of the
results of SEC survey and study of geomorphic features. The chemical analysis of cation and anions were carried out in the
Hydrogeology Laboratory of the Department of Geology and Mining, University of Rajshahi and
Central Science Laboratory, University of
Rajshahi, SRDI and government recognized
laboratories. The chemical parameters were determined in the laboratory following
the standard analytical procedures. |
