5 research outputs found
SALTWATER – FRESHWATER WETLAND ECOSYSTEM AND URBAN LAND USE CHANGE IN PORT HARCOURT METROPOLIS, NIGERIA
Urban development in wetland ecosystems for human settlement, transport networks, exploration /exploitation of
natural resources, agriculture and industrial development is one of the biggest menace to wetland change and
management. To estimate future urban expansion is very crucial for urban planners and environmental managers in
fastest growing cities. This study aims to examine the saltwater/freshwater ecosystem and urban land use change in
Port Harcourt metropolis, Nigeria. Sources of data for this study were acquired from a time series of landsat Thematic
Mapper (TM) and Enhanced Thematic Mapper plus (ETM+) with Thermal Infrared Sensor (TIRS) images were used to
derive land use and land cover maps of the Port-Harcourt metropolis. This study revealed that both freshwater wetland
and saltwater wetlands ecosystem occupied 46.99% (18837.1 Ha) of the total classes. This may be the result of wetland
being in an undisturbed nature without any conversion or alteration for use. The urban land use change of PortHarcourt metropolis had changed dramatically during the period of 29 years. The two wetlands (saltwater and
freshwater wetland) sum up to a total of 40% (16497.5 Ha) which indicates that there is pressure on wetland use such
as plant products harvested from fuel wood, human settlement, urban agriculture, sand dredging, sanitation, water
pollution and industrial activities from oil companies within the metropolis. Efforts should be made to increase
knowledge, sensitization, consultation, stakeholder’s participation and awareness on the wetlands values and wise use
economy through dissemination of information, using appropriate techniques and training of adequate staff as well as
the need for sound wetland policies, laws and legislation for sustainable use, management and control in conservation
of wetland
Some Physical Properties of Vernonia amygdalina and Garcinia kola Microspheres Prepared with High Molecular Weight Polyethylene Glycols
The effect of polymer concentrations on some of the physicochemical
properties of Vernonia amygdalina (Linn) and Garcinia kola (Heckel)
extracts loaded microspheres was evaluated. Microspheres of the aqueous
extracts was prepared by emulsion solvent evaporation using
polyethylene glycol (PEG) mixtures of molecular weight 4000 and 6000 at
different ratios of 1:0, 0:1, 1:1, 1:2 and 2:1 while the amounts of the
extracts incorporated was constant for all ratios. The microspheres
were evaluated for their particles sizes, yield, flavonoid content,
loading efficiency, moisture loss and flow properties. In-vitro release
studies were carried out by monitoring flavonoid release rate from the
microspheres. The microspheres were spherical and uniformly shaped and
exhibited good flow characteristics. Their size range, yield, loading
efficiency, moisture loss and flavonoid content were 76 - 83 \u3bcm,
49 - 76 %, 47 - 82 %, 2.18 - 4.60 % and 17.10 - 23.80 mg%, respectively
for V. amygdalina and 144 - 160 \u3bcm, 50 - 68 %, 51 - 68 %, 3.00 -
4.41 % and 20.00 - 28.70 mg%, respectively for G. kola. Flavonoids
release from the microsphere was up to 90 % within 1 h and it followed
a matrix release kinetic model with a super case-II transport
mechanism. The concentrations of the polymers affected the yield,
loading efficiency, moisture loss and the extent of flavonoid release
of the microspheres but had no effect on their particle sizes and
flavonoid content. These results may find useful application in the
delivery of V. amygdalina and G. kola extracts since the combination of
PEG of different molecular weights resulted in microspheres with good
physicochemical and release properties