Environmental Mapping of Potential Habitats for Anthropod Vectors of Trypanosomiasis in Northern Nigeria

This paper presents analysis of a cost effective methodology using remotely sensed data analysed within a geographical systems (GIS) environment for mapping out potential habitats of anthropod vectors responsible for trypanosomiasis in northern Nigeria. These geographical locations are areas with high population of livestock in Nigeria. Animal Trypanosomiasis is considered as an arthropod-borne viral disease which is endemic in about 37 countries of the sub-Saharan Africa and in particular northern Nigeria. This anthropod-borne viral disease remains a threat to both humans and livestock in many communities, and the outbreak of such diseases is shown to relate to fluctuations in the changing climate mostly experienced whenever there are changes in global precipitation which also relates to changes in sea surface temperatures otherwise known as “El Niňo Southern Oscillations” (ENSO). Monthly Satellite imageries in the form of Normalised Difference Vegetation Index (NDVI) at 250 meters spatial resolution obtained from NASA-MODIS/CMD were subjected to principal component analysis utilizing the standardized principal components within a GIS environment and supplemented with Digital Elevation Model (DEM) data in the analysis. Results from the maps showed that pockets of probable habitats of these anthropod vectors responsible for trypanosomiasis mostly located around forest islands characterized by dry woodland and savanna, and in some cases around gallery forests and few lowland and riverine areas. This study provides baseline information for policy makers in Nigeria and other stakeholders as a cost effective measure for mapping potential habitats for anthropod vectors responsible for trypanosomiasis in Northern Nigeria. Further studies are encouraged so as to clearly understand the magnitude and actual locations of the habitat of this vector and find ways of targeting their locations for minimizing or even eradicating these vectors.

Multisensor Comparisons for Validation of MODIS Vegetation Indices

Vegetation indices （Ⅵ） are one of the standard science products available from the Moderate Resolution Imaging Spectroradiometer （MODIS）. Validation of MODIS-Ⅵ products was an important prerequisite to using these variables for global modeling. In this study, validation of the MODIS-Ⅵ products including single-day MODIS, level 2 （gridded） daily MODIS surface reflectance （MOD09）, 16-day composited MODIS （MOD13） was performed utilizing multisensor data from MODIS, Thematic Mapper （TM）, and field radiometer, for a rice-planting region in southern China. The validation approach involved scaling up independent fine-grained datasets, including ground measurement and high spatial resolution imagery, to the coarser MODIS spatial resolutions. The 16-day composited MODIS reflectance and Ⅵ matched well with the ground measurement reflectance and Ⅵ. The Ⅵ of TM and MODIS were lower than the ground Ⅵ. The results demonstrated the accuracy, reliability, and utility of the MODIS-Ⅵ products for the study region.

Spatial Assessment of Flood Vulnerability in Aba Urban Using Geographic Information System Technology and Rainfall Information

This study investigated the relationship between topographic information and trends in rainfall in Aba urban, South Eastern Nigeria. GIS data were applied to generate topographical information on?runoff characteristics, the slope, the contour, the aspect and the digital elevation model. The Mann-Kendall Trend was applied to the rainfall data to show if a monotonic increase, decrease or stability trend exist for the rainfall data of Aba metropolis for the period 2000-2010. Results showed that virtually all parts of Aba were liable to floods expect Ogbor hill axis. The flood vulnerability map indicated that 71.65% of the study area was vulnerable to flood. Rainfall trend showed a decrease in six out of the ten year period. Since within this period, flood intensity had generally remained the same, we concluded that topography, poor drainage infrastructure and non-compliance with building, planning and environmental regulations rather than rainfall trend were the key cause of flood problem in the study area.

Coupling of zero valent iron and biobarriers for remediation of trichloroethylene in groundwater

This study attempted to construct a three series barrier system to treat high concentrations of trichloroethylene （TCE; 500 mg/L） in synthetic groundwater. The system consisted of three reactive barriers using iron fillings as an iron-based barrier in the first column, sugarcane bagasse mixed with anaerobic sludge as an anaerobic barrier in the second column, and a biofilm coated on oxygen carbon inducer releasing material as an aerobic barrier in the third column. In order to evaluate the extent of removal of TCE and its metabolites in the aquifer down gradient of the barrier system, a fourth column filled with sand was applied. Residence time of the system was investigated by a bromide tracer test. The results showed that residence time in the column system of the control set and experimental set were 23.62 and 29.99 days, respectively. The efficiency of the three series barrier system in removing TCE was approximately 84% in which the removal efficiency of TCE by the iron filling barrier, anaerobic barrier and aerobic barrier were 42%, 16% and 25%, respectively. cis-Dichloroethylene （cis-DCE）, vinyl chloride （VC）, ethylene and chloride ions were observed as metabolites following TCE degradation. The presence of chloride ions in the effluent from the column system indicated the degradation of TCE. However, cis-DCE and VC were not fully degraded by the proposed barrier system which suggested that another remediation technology after the barrier treatment such as air sparging and adsorption by activated carbon should be conducted.