| dc.description | Water is vital to the existence of al} living organisms, but this valued resource is increasingly
being threatened as human populations grow and demand more water of high quality for
domestic purposes and economic activities. Water abstraction for domestic use, agricultural
production, mining, industrial production, power generation, and forestry practices can lead
to deterioration in water quality and quantity that impact not only the aquatic ecosystem (i.e.,
the assemblage of organisms living and interacting together within an aquatic environment),
but also the availability of safe water for human consumption. It is now generally accepted
that aquatic environments cannot be perceived simply as holding tanks that supply water for
human activities. Rather, these environments are complex matrices that require careful use to
ensure sustainable ecosystem functioning well into the future. Moreover, the management of
aquatic environments requires an understanding of the important linkages between ecosystem
properties and the way in which human activities can alter the interplay between the physical,
chemical and biological processes that drive ecosystem functioning. | en_US |
| dc.description.abstract | Groundwater (70 samples from tubewells and shallow tubewells) and surface water (18
samples from 3 rivers in 18 sampling sites) collected from the Dinajpur Sadar Upazilla,
Dinajpur, Bangladesh in dry season of the year June, 2012 to Feb, 2013 and analyzed for its
quality and suitability for different purposes. Analyses included pH, EC, temperature,
Dissolved Oxygen (DO), Chemical Oxygen demand (COD), alkalinity, cations (Ca**, Mg”*,
Na’, K*, Zn**, Cu’*, Mn”* and Fe**), anions (CO;”, HCO;, NH3, NO2, NOs, SO,”, total
nitrogen, total phosphorus and Cl) and TDS. Several variables such as SAR, SSP, RSC and
hardness were also computed. Water samples contained Ca’*, Mg”* and Na‘ as the dominant
cations and HCO; and CI were the dominant anions. Most of the samples were suitable for
different purposes.
Water eutrophication has become a worldwide environmental problem in recent years, and
understanding the mechanisms of water eutrophication will help for prevention and
remediation of water eutrophication. In this study, recent advances in current status and major
mechanisms of water eutrophication, assessment and evaluation criteria, and the influencing
factors were reviewed. The assessment of water eutrophication has been advanced from
simple individual parameters like total phosphorus, total nitrogen, etc., to comprehensive
indexes like total nutrient status index. The major influencing factors on water eutrophication
include nutrient enrichment, hydrodynamics, environmental factors such as temperature,
salinity, carbon dioxide, element balance etc. and microbial and biodiversity. The occurrence
of water eutrophication is actually a complex function of all the possible influencing factors.
The mechanisms of algal blooming are not fully understood and need to be further
investigated. The decomposition of organic phosphorus in natural water is determined by a
large number of physical driven transformation processes. Many of these processes are
known in principle but often the decomposition rate into the aquatic environment in a number
of different forms, and have been described as being can hardly be measured with a sufficient
spatial and temporal resolution. Phosphorus is introduced present in the dissolved phase as a
small fraction of the total and in the particulate phase as a large fraction of the total. Each
fraction is made up of a large number of different components, most of which may change
between their dissolved or particulate state. The decomposition rate coefficients of POP and
DOP are 0.038 day” and 0.251 day respectively. These decomposition coefficients might be
suitable for modeling the water quality. | en_US |
