Influence of Vehicle Traffic Emissions on Spatial Variation of Ozone and its Precursors in Air of Port Harcourt City, Nigeria

This study aimed at assessing the influence of vehicle traffic on spatial variation of ozone (O3) and its vehicular emission precursors in the air of Port Harcourt city. Sampling was carried out in ten (10) sites, eight (8) located within the high traffic density area (study sites) and two (2) located within the very low traffic density area (reference sites). The precursor pollutants measured were nitrogen dioxide (NO2), carbon monoxide (CO) and volatile organic compounds (VOCSs). Ozone and the precursor pollutants were measured in situ using AeroQUAL 500 series portable ambient air analyzer while traffic flow survey was achieved by direct counting. Measurements were carried out at morning, evening and off-peak traffic periods respectively. The mean concentrations of ozone and the precursor pollutants were significantly higher (p = 0.05) in the study sites than in the reference sites. Mean concentrations were higher at peak traffic periods than at off-peak traffic periods except for ozone that was higher at off-peak than at morning peak. There was significant correlation between traffic density and each of the pollutants including ozone. The spatial variability in concentration of pollutants was influenced by vehicular traffic. VOCs and NO2 levels were higher than the National Ambient Air Quality Standard (NAAQS) limit of 0.05 ppm and 0.04 – 0.06 ppm respectively, O3 concentration was below the standard limit (0.06 ppm) but was at the verge of exceeding. Traffic emission within the city was significant and could be mitigated through regular monitoring and control

Comparative evaluation of reproductive performance and some egg quality parameters of black and white skinned snails

One hundred sexually matured snails, fifty each of the black skinned and white skinned ectotypes were used in the evaluation of reproductive performance and egg quality traits in a study that lasted for eighty-four days. The reproductive performance traits measured included clutch size (number of eggs laid per clutch), incubation period (days) of eggs, percent hatchability, and percent mortality and survivability, while the egg quality traits evaluated included egg weight and length. Results obtained showed significant differences at different levels among parameters measured in the two ectotypes of snails studied. The results of reproductive traits showed that mean clutch sizes were 5 and 4 for black skinned and white skinned ectotypes respectively. Mean incubation periods were 25.8 days for the black skinned ectotype and 22 days for the white skinned ectotype. The values for mean percent hatchability were 26.8 % and 22.8 % for the black skinned and white skinned ectotypes respectively. Mean survivability values were 22.8 % for black skinned ectotype and 20 % for the white skinned ecotype. The mean egg quality parameters were 2.7 g and 2.4 g, weight for black skinned and white skinned ectotypes respectively. The mean egg lengths were 4.6 mm and 4.2 mm for black skinned and white skinned ectotypes respectively. Among the measured parameters, clutch size and egg length had very high significant difference (

Environmental factors forcing pattern of in-stream fish assemblages of the lower cross river estuary at Oron, southeast Nigeria

No Abstract

Utilization and fate of phosphorus of different sources applied to cohesive soil of Amazonian periphery

ABSTRACT In the Amazonian region, P is often a primary factor limiting sustainable agrosystems. We compared the efficiencies of local aluminous phosphate (ALP) and single superphosphate (SSP) under a cover of leguminous residues to determine the fate of P sources in an Amazonian soil with hardsetting characteristics. The experiment followed a randomized block design with four replications and the following treatments: ALPU, i.e. ALP plus urea (U); ALPL, i.e., ALP plus leucaena (L); SSPU, i.e., SSP plus urea; SSPL, i.e., SSP plus leucaena; and BS, i.e., bare soil (without residues). To assess the residual values of the P sources, we used a sequence of crops consisting of maize, cowpea and cassava. Both ALP and SSP exhibited low P efficiency in BS. The greatest amounts of P and N uptake in the plots where P sources and leucaena residues were added, as in those covered with leucaena residue, resulted in higher productivity levels. These differences are important for the adoption of beneficial soil management practices and the use of P sources to enhance efficiency in tropical soils. The use of residues increased the P use efficiency of both P sources, as it enhanced the uptake of both N and soluble P. The replacement of SSP with ALP may be advantageous in the second year of planting with high-demand crops, but the P of the SSP retained in the minus soluble fractions may be available if the SSP is used in P-depleting crops combined with no-tillage underneath a mulch of residues

Prevalence of urinary schistosomiasis in Nigeria, 1994–2015: Systematic review and meta-analysis

Introduction: The Global significance of schistosomiasis started waning over the years owing to its eradication in most developed societies, until the reawaking of global attention and it now occupies a prominent place amongst the neglected tropical diseases (NTD). The aim of our study was to accurately estimate the prevalence of schistosomiasis in Nigeria, and its six geo-political zones. Subjects and methods: We utilized electronic databases to search and select studies on prevalence across the geographical zones between 1994 and 2015. STATA 10 Random effects meta-analysis of observational studies was used to generate our estimates. Result: Sixty-seven studies met the inclusion criteria. The unified pooled population studied was 47,440 (n = 14,888 persons). The pooled prevalence]) of Schistosoma haematobium infestation was, for all regions = 34.7% (31.0–38.5) (95% confidence interval [CI)). Conclusion: Schistosomal infestations remain hyperendemic in Nigeria. Nigeria must, therefore, expedite the execution of resolution WHA66.12 adopted by the World Health Assembly on NTD