Environment and Forestry

Water demand in Abeokuta, Nigeria and bacteriological content of public water supplied by the Ogun State Water Corporation, major water supplier in Abeokuta; is assessed in this paper. The water demand of the population was estimated for ten years based on the 2006 National Population Census result, using the geometric projection method. Forty sampling locations were also randomly selected in the city of Abeokuta. Water samples were collected - during the rainy and dry season. The samples were analyzed for total and faecal coliform count using the Most Probable Number method. The presence of Escherichia coli was detected in 39 of a total of 80 samples collected in both seasons. Water demand ranges from 2.01 x 10-7 m3 - 2.48 x 10-7 m3 per year. However, the current volume of water supplied, about 82 million litres per day (2.99 x 10-7 m3 per year), that is when the public utility is in operation is only sufficient to meet the current water demand of the population. The paper argued the need for urgent expansion of the water scheme to adequately meet the present and future water needs of the population and by extension the targets of the Millennium Development Goals by 2015. The paper concludes on the need for periodic monitoring of the state of water from the distribution pipe network from source to the point of use, as well as the water quality parameters that are necessary to ensure the safety of water.

Locally produced fruits (mango, pineapple and banana) were sampled and purchased from farms and markets within the Yilo and Lower Manya Krobo districts and analyzed for pesticide residues by gas chromatography equipped with an Electron Capture Detector (GC-ECD). In all, 80 samples made up of 40 mango samples and 20 samples each of pineapples and bananas were extracted and analyzed for mainly organochlorine residues (?-HCH, ?-HCH, aldrin, dieldrin, heptachlor, ?-chlordane, endosulfan s, p, p’-DDE etc.) and synthetic pyrethroid residues (allethrin, bifenthrin, fenpropathrin, permethrin, cyfluthrin etc.). Analysis indicates that about 88% of the mangoes sampled from the farms contained one or more of these pesticide residues. 75% and 65% of the pineapples and bananas respectively from farms and markets had one or more of the analyzed pesticide residues. The data revealed that about 6.2% of the fruit samples analyzed contained organochlorine pesticide residues of ?-HCH (0.013mg/kg and 0.038mg/kg respectively in mangoes and pineapples); ?-HCH [0.014mg/kg (mango) and 0.024mg/kg (pineapple)]; methoxychlor [0.027mg/kg (mango) and 0.048mg/kg (pineapple)]. Synthetic pyrethroid residues of cyfluthrin [0.078mg/kg (mango) and 0.059mg/kg (pineapple)] and fenvalerate [0.025mg/kg and 0.028mg/kg respectively for mango and pineapple] were also found above their respective maximum residue limits whereas 78.2% of detected pesticide residues were below the MRLs. Nonetheless, the continuous consumption of these fruits with even the modest pesticide levels can result in accumulation that could result in deadly chronic effects. In assessing the consumers’ perception of pesticide residues in fruits, about 69% of the respondents were aware of pesticide residues in fruits and the corresponding adverse effect on human health. Some have experienced pesticide poisoning after fruit consumption. Thus many wish pesticide usage in fruit and crop cultivation in general is curbed or minimized to only those who can ensure reduced levels.

The main objective of this study was the determination of optimum energy requirement and potential of greenhouse gas (GHG) reduction of eggplant production by non-parametric method of data envelopment analysis (DEA) in Guilan province, Iran. The BCC and CCR models of DEA were applied to energy optimization. The results showed the 29, 39 and 30 units had the score equal one in technical, pure technical and scale efficiency, respectively. Also, the average of technical, pure technical and scale efficiency was calculated as 0.771, 0.956 and 0.806, respectively. The total saving energy was about 2830 MJ ha-1 and diesel fuel had the highest share of total energy saving with 48.49%. The energy use efficiency of target units was more than present units about 26%. The GHG emissions analysis indicated that total GHG emissions of present and optimum units were about 515 and 401 kgCO2eq. ha-1, respectively. So, the total potential of GHG emissions reduction was found about 115 kgCO2eq. ha-1. Moreover, the diesel fuel had the highest percentage of GHG emissions reduction by 58.58%; followed by machinery with 17.24% and nitrogen with 15.12%. Generally, it can be said the DEA approach was appropriate methods for energy optimization and reduction of GHG emissions in eggplant production.

The significance of temperature and geothermal gradient in relation to hydrocarbon occurrence in the BARA Field, western Niger Delta was studied using bottom hole temperature logs. The average depth to the floor of the oil generative window (7182.3m) shows that commercial hydrocarbon accumulation still lies below the final drilled depth in the field. The average geothermal gradient of 1.74 oC /100m shows that the field is thermally mature for commercial accumulation of hydrocarbon. This is evidenced in the occurrence of hydrocarbon in the wells drilled within the field. The geothermal gradient decreases radially from the centre of the field to the edges based on the position of the five wells in the field, this is confirmed by the average thermal conductivity which tends to increase radially from the centre to the edges. Areas with high shale percentage show high geothermal gradient values while areas with high sand percentage show low geothermal gradient values. Significant hydrocarbon occurrence lies below the top of the calculated depth of oil ceiling (3508.89m) and within the oil generative window of the worldwide catagenesis range (50oC to 200oC). Rapid change in geothermal gradient occurs in intervals where there are hydrocarbon accumulation showing that, changes in geothermal gradient can be used to enhance exploration activities. The occurrence of hydrocarbon within the oil generative window in terms of temperature and depth, suggests that adjacent shales of the Agbada Formation are possible source rock.

The aim of this study was to determine greenhouse gas (GHG) emissions and indicators for energy use and to evaluate energy sensitivity of seed and grain corn production in Pars Abad Moghan, Iran. The data was collected by a face-to-face interview method from 144 corn farms during 2011 year. Most of energy consumption in seed and grain corns was related to diesel fuel and chemical fertilizers. The net energy, energy productivity, energy intensity and GHG emission were -4688.77 MJ ha-1, 0.06 Kg MJ-1, 16.4 MJ Kg-1 and 1810.11 kg CO2eq ha-1 for seed corn and 58330.63, 0.18, 5.53 and 1490.13 kg CO2eq ha-1 for grain corn, respectively. The percentage share of renewable, nonrenewable, direct and indirect energies were 3, 97, 46 and 54 for seed corn, and 2, 98, 50 and 50 for grain corn, respectively. The highest value of GHG emission belonged to diesel fuel with share of 64.22% and 66.66 % of total emission for seed and grain corn, respectively. An econometric model was also developed to estimate the impact of energy inputs on yield by using Cobb-Douglas production function. For this purpose, seed and grain corn yields were assumed to be functions of energy inputs.

There is a depletion of Vitellaria paradoxa populations mainly due to agricultural encroachment, seasonal fires and over exploitation notwithstanding its numerous benefits. This has affected natural regeneration and altered population structure of the species. The objectives of the study were 1) to determine the density of regeneration, saplings and mature V. paradoxa under different land use types 2) to determine stand structure of V. paradoxa under various land use types and 3) to compare the population structure of saplings and mature trees. Fifteen plots each of 20*20m were established using systematic random sampling in different land use types: Cultivated fields, fallow land and virgin land for the measurement of tree heights, diameters and number of individuals. Fallow land recorded higher regeneration and saplings density compared to the other land uses. Mature V. paradoxa was dominant in cultivated land. Fallow land had more stable population with better regeneration compared to cultivated land and virgin land. Height of regeneration in cultivated land was significantly different (p?0.05) compared to the other land use types. There was no significant difference between saplings stand structure. Mature Vitellaria paradoxa stand structure in cultivated fields was significantly different (p?0.05) compared to the other land use types. This study confirms that different land use types influence the population structure of Vitellaria paradoxa and there is anthropic selection.