Natural resource abundance in Nigeria: From dependence to development

There are several strategies open to an economy in its attempt to attain sustainable economic development depending on its historical background and resource endowment. One of such is the resource-led strategy. Nigeria is superabundantly rich in crude oil and has reaped billions of petrodollars. However, the country seems to be facing the problem of successfully translating this huge oil wealth into sustainable development. This paper employs the vector error-correction methodology in examining the long-run impact of the huge oil wealth accruing to Nigeria on its economic development. Indicators such as per capita GDP (PGDP), household consumption, infrastructural development (electricity), and agricultural and manufacturing output growth rates are examined. The results suggest a significant positive long-run impact of per capita oil revenue on per capita household consumption and electricity generation, while a negative relationship is established for GDP, agriculture and manufacturing. Even for those variables with negative relationship at current period, there exist positive relationships at subsequent lags. Thus, oil revenue, if properly managed and invested, could be effectively used to induce oil-led development in Nigeria provided the current inhibitions of corruption, lack of transparency, accountability and fairness in its use and distribution are removed.     

The contribution of roadside soil to phosphorus loading in the eutrophic Lagos Lagoon, Nigeria

Roadside soils were sampled from the Lagos Lagoon catchment during the wet and dry seasons over the period 2005-2009. Lagoon sediment samples were also collected within the same period. All samples were digested with aqua regia to determine total phosphorus and extracted with 0.5 M sodium bicarbonate to determine the bioavailable fraction (Olsen-P). A segmented flow analyser method was used for analysis and good accuracy was demonstrated for two reference soils (SO-2 from CCMET and SRM 2711 from NIST). The Lagos Lagoon is a hypereutrophic water body (1270 ± 1170 μg P L(-1)), with significant areas of anoxia and water hyacinth growth. The total phosphorus concentrations in roadside soils (16 sites; mean ± 2 S.D.) were 285 ± 279 mg kg(-1) in the wet season and 424 ± 629 mg kg(-1) in the dry season, indicating that rainwater leaching is a major source of phosphorus in the lagoon. The bioavailable fractions were 5.17 ± 3.47 mg kg(-1) (2.1 ± 1.5% of the total) in the wet season and 13.0 ± 8.7 mg kg(-1) (4.3 ± 4.5% of the total) in the dry season.     

Risk assessment of landfill disposal sites--State of the art

A risk assessment process can assist in drawing a cost-effective compromise between economic and environmental costs, thereby assuring that the philosophy of 'sustainable development' is adhered to. Nowadays risk analysis is in wide use to effectively manage environmental issues. Risk assessment is also applied to other subjects including health and safety, food, finance, ecology and epidemiology. The literature review of environmental risk assessments in general and risk assessment approaches particularly regarding landfill disposal sites undertaken by the authors, reveals that an integrated risk assessment methodology for landfill gas, leachate or degraded waste does not exist. A range of knowledge gaps is discovered in the literature reviewed to date. From the perspective of landfill leachate, this paper identifies the extent to which various risk analysis aspects are absent in the existing approaches.     

Mapping Turbidity in the Charles River, Boston Using a High-resolution Satellite

The usability of high-resolution satellite imagery for estimating spatial water quality patterns in urban water bodies is evaluated using turbidity in the lower Charles River, Boston as a case study. Water turbidity was surveyed using a boat-mounted optical sensor (YSI) at 5 m spatial resolution, resulting in about 4,000 data points. The ground data were collected coincidently with a satellite imagery acquisition (IKONOS), which consists of multispectral (R, G, B) reflectance at 1 m resolution. The original correlation between the raw ground and satellite data was poor (R2 = 0.05). Ground data were processed by removing points affected by contamination (e.g., sensor encounters a particle floc), which were identified visually. Also, the ground data were corrected for the memory effect introduced by the sensor's protective casing using an analytical model. Satellite data were processed to remove pixels affected by permanent non-water features (e.g., shoreline). In addition, water pixels within a certain buffer distance from permanent non-water features were removed due to contamination by the adjacency effect. To determine the appropriate buffer distance, a procedure that explicitly considers the distance of pixels to the permanent non-water features was applied. Two automatic methods for removing the effect of temporary non-water features (e.g., boats) were investigated, including (1) creating a water-only mask based on an unsupervised classification and (2) removing (filling) all local maxima in reflectance. After the various processing steps, the correlation between the ground and satellite data was significantly better (R2 = 0.70). The correlation was applied to the satellite image to develop a map of turbidity in the lower Charles River, which reveals large-scale patterns in water clarity. However, the adjacency effect prevented the application of this method to near-shore areas, where high-resolution patterns were expected (e.g., outfall plumes).     

Greening Nigeria's economy for industrial and environmental sustainability: Polyurethane production as a test case

The study focused on Nigeria's polyurethane (PU) production process as a test case. Though it is currently insignificant when viewed from a global perspective, PU production in Nigeria is not eco‐friendly. Traditionally, PU is produced by reacting petro‐based polyol with a poly‐isocyanate, which is made from amines and phosgene and are currently imported into the country. These two materials are detrimental to the human health and environment, indicating that Nigeria's PU industries need to re‐examine their production inputs for environmental compliance. The objective of this study is to review the PU industry for nontoxic reagents that could be sourced locally vis‐à‐vis overcoming sustainable development (greening the economy) challenges in Nigeria. Non‐isocyanate polyurethane (NIPU) is preferred to petro‐polyurethane because, in comparison, NIPU has improved thermal and chemical resistance, porosity and water absorption, and is less toxic. Engaging local resources to produce PU is economically feasible; in addition, NIPU is relatively advantageous to human health and the environment. Aside from being economically feasible, production of NIPU in Nigeria has the propensity to greatly enlarge the growth of the existing PU industry to tremendous heights and contribute to diversifying and improving the overall economy.     

Decolourization, degradation and detoxification of textile dyes by Aspergillus species

Decolourization, degradation and detoxification of four textile dyes (Madonna Blue, Pagoda Red, Market Blue and Market Red) by four Aspergillus species was carried out. The decolourization/degradation ability of the isolates was analyzed on the fifth day using UV/Visible spectrophotometer and FTIR spectrophotometer, while detoxification of the dyes was determined using phytotoxicity test. At the initial concentration of 200 mg/L of the dyes, the percentage decolourization potential of the fungal isolates ranged between 80.89 and 86.26% for Madonna Blue, 71.38–84.76% for Market Red, 70.46–79.46% for Market Blue and 60.68–74.82% for Pagoda Red in decreasing order. Aspergillus fumigatus (8F) demonstrated consistently highest decolourization potential for all the dyes than other isolates. Decrease in percentage decolourization of the dyes was observed when the concentration of the dyes was increased gradually from 100 to 500 mg/L at 100 mg/L interval. Percentage decolourization of Pagoda Red reduced from 60.68 to 10.31%, 66.47 to 19.71%, and 74.82 to 26.19% with A. ustus (3D), A. fumigatus (3E) and A. fumigatus (8F) respectively. Degradation of the dyes moiety using FTIR spectrum showed loss of functional groups such as C=O, C=N, C=C and C–H stretch of benzene, with the formation of new functional groups such as N=O group, C≡C group and OH group of alcohol in the Madonna Blue and Pagoda Red samples treated with A. fumigatus (8F) when compared with untreated samples. Phytotoxicity study of the treated and untreated dye samples on maize germination showed the plumule and radicle length of positive control (water) to be 12.38 ± 1.20 and 5.62 ± 0.33 while untreated Madonna Blue was 6.68 ± 1.10 and 3.34 ± 0.92, A. fumigatus (3E) treated sample had 8.60 ± 0.59 and 4.32 ± 0.91 respectively. This study revealed the metabolic versatility of Aspergillus species to decolourize, degrade and detoxify textile dyes.     

Efficiency of cassava steep liquor for bioremediation of diesel oil-contaminated tropical agricultural soil

Soil artificially contaminated with diesel oil, treated with cassava steep liquor (CSL) and designated EXPS. Similar polluted soil without CSL amendment (CSS1) and uncontaminated soil (CSS2) served as controls. There were dramatic changes in the physico-chemistry of systems EXPS and CSS1 with utilization of the inorganic nutrients to near-depletion in the former than the latter. In contrast, the properties of CSS2 remained relatively stable throughout the investigated period. Similarly, the population densities of microflora in the polluted soils showed an initial decrease between days 0 and 5 before assuming an increasing trend with percent hydrocarbon-utilizers ranging significantly (P < 0.05) from 0.56 to 6.6, 0.1 to 2.46 and 0.56 to 0.26, respectively for EXPS, CSS1, and CSS2. In EXPS, the residual oil decreased from 98,045 to 1,102.3 mg/kg soil at day 35 representing about 98.88% degradation. The corresponding value for CSS1 was 98,106.1 to 52,110 mg/kg soil, amounting to 46.88% oil disappearance. The GC fingerprints of alkane fractions of the recovered oil reduced significantly by day 15 for EXPS with near-similar results of CSS1. However, by day 35, there was complete disappearance of all peaks including the pristane and phytane molecules in the former whereas in CSS1, there were no observable changes. The germination and growth profiles of maize seed plants as evidence of recovery of oil-impacted soils were poor in CSS1 (10%) with pronounced abnormal morphology when compared with the data obtained for EXPS (74%) and CSS2 (80%). These results suggest that CSL could be an indispensable tool in bioremediation of environments contaminated with hydrocarbons. The technology of application is simple, rapid and cost-effective and may be appropriate for use in developing countries to ameliorate the problems of petroleum pollution.