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