COLERM Proceedings

Title Page

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Editorial Board of the Environmental Management Conference 2011

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Chairpersons of Technical Sessions

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Citation

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Group Photography

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Opening Address by the Vice- Chancellor, Prof. Oluwafemi Olaiya Balogun

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Table of Content

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LAND DEGRADATION, WATER AND AIR POLLUTION

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Soil Physical Properties and Hydraulic Conductivity of Compacted Sandy Clay Loam Planted with Maize Zea Mays

A. J. Adesigbin — 2012-04-05

Land degradation from soil compaction has a major influence on the hydraulic conductivity, total porosity (PT), micro porosity (MIC), macro porosity (MAC), roots growth and grain yield. Field experiment was conducted in a tilled and compacted sandy clay loam soil under different machinery passes to determine compaction effects on soil bulk density, total porosity (PT), micro-porosity (MIC), macro-porosity (MAC), hydraulic conductivity and growth characteristics of maize. Four plots; A, B, C and D, each of area 5 x 10 m² were used. Plot A was tilled with a tractor-mounted disc plough and the remaining three plots; B, C and D were subjected to 5, 10 and 15 passes, respectively of heavy duty Mercy Fergusson tractor model 4355 (3.82 Mg ). Compacted plots progressively increased in bulk density between 1.63g to 1.90 g, while total porosity decreased from 38 to 28.3 % in plots under 5 and 15 traffic passes, respectively. Soil micro-porosity decreased from 9.6 % to 7.84 % and from 17 % to 9.17 % in the soil superficial layer (0-10 cm) and at the 10-20 cm layer, respectively while the macro porosity ranged from 28.64 % to 20.45 % and 24.3 % to 19.12 % in the 0 - 10 and 10 - 20 cm soil layers, respectively. At suction of 2 cm s^-1, tilled plot had the highest cumulative infiltration rate of 3.42 cm s^-1and hydraulic conductivity of 9.09 x 10^-3. Results show that different machinery passes poses different restrictions to rooting depths of maize.

Sustainable Management of Mangrove Coastal Environments in the Niger Delta Region of Nigeria: Role of Remote Sensing and GIS

O. H. Adedeji — 2012-04-05

Wetlands, which include the coastal mangroves, are amongst the Earth’s most productive ecosystems. They support millions of people and provide a wide range of direct and indirect goods and services or functions. Despite the wide range of important ecosystem goods and services provided by the wetlands they are under serious threat to extinction worldwide. Due to mainly: erratic and haphazard physical developments, externalities from users (e.g. agriculture, oil and gas industry. In Nigeria, 21,342 hectares of mangrove vegetation was reported to have been lost between 1986 and 2003 due to urbanization, dredging activities, and pollution from the oil and gas industries. Recognizing the continuous degradation of the region, mangrove (or wetland) goods and services must be given a quantitative value if their conservation is to be well appreciated. GIS and RS offer opportunities in accurate monitoring and assessment of environmental changes and effects taking place in the mangrove areas. It also helps to identify the driving forces of the environmental changes. GIS mapping will assist in assessing the spatial distribution and ecological change of the environment, identifying the baseline data of the region such as vegetation types and densities, the land use types. GIS and RS will complement many existing cases of wetland (including mangrove restoration developments) and provide government and all stakeholders involved in the development of the region with strategic framework for identifying and calculating projects and programs for the restoration of degraded mangroves and development of conservation action Plans for the sustainable management of Niger Delta mangroves.

A Comparative Study of Portland Cement, Hydrated Lime and Lateralite as Stabilizing Agents of Quaternary Coastal Plain Sands North of Lagos Metropolis and as Road Construction Material

E. A. Meshida, — 2012-04-05

The Lagos end of the Lagos-Ibadan expressway has been constructed within a wetland terrain of South Western Nigeria. The section was constructed upon a thick deposit of relatively loose, silty and slightly clayey sand technically referred to as the Coastal Plain Sand. The formation is a major sedimentary deposit in Southern Nigeria, and it is a major road construction soil material in the northern environs of the Lagos metropolis that has been massively quarried by many road contactors as borrow materials for several years. Previous and present studies confirm the substandard geotechnical properties of the deposit as road construction material. It requires substantial improvement through stabilization by additives. This study examines the effect of three fluxes, namely Portland cement, Hydrated Lime and newly evolved “Lateralite’’ on the compaction and California Bearing Ratio (CBR) characteristics on several samples of the deposit. Lateralite offered the highest hope of stabilizing the deposit effectively for highway construction on account of its significant anti-shrinkage/swelling control and CBR enhancing effect on treated samples of Coastal Plain Sand deposit.

Aspects of the Hydrology of the Western Niger Delta Wetlands: Groundwater Conditions in the Neogene (recent) Deposits of the Ndokwa Area

I. A. Akpoborie — 2012-04-05

Groundwater conditions in the thin Neogene deposits of the Sombreiro-Warri Deltaic Plain and the Freshwater Swamp physiographic environments of the Ndowa area are not well understood. Physical examination indicates that the deposits are lithologically similar to those of the Benin Formation. All deposits exhibit a fining upwards cyclical sequence of fine, medium-coarse grained and pebbly quartz and feldsphatic sands and differ from each other only in the topmost superficial cover of approximately 6-10m thickness. The configuration of the water table as deduced from measurements in dug wells show that it mirrors the general topography. Ground water movement is unidirectional from the recharge mound centered on Urhonigbe towards the south and east of the area into a major ground water sink stretching from Ogume to Aboh and beyond. The sink evidently sustains the surrounding wetlands year round. Transmissivity of the multilayered aquifer is estimated at 71m² per day. Differences in the chemistry of groundwater from the three physiographic regions are reflected in elevated levels of lead and cadmium at an average concentration of 0.01mg/l and 0.13mg/l respectively in the Sombreiro-Warri Deltaic Plain terrain. Furthermore, while the order of cation abundance in Benin Formation outcrop groundwater is Ca>Mg>K>Na, it is Na>K>Ca>Mg in the Sombreiro-Warri Deltaic Plain and the Freshwater Swamps. Coliform bacteria occur in all samples tested. These findings have important implications for water and environmental management of the Ndokwa area that deserve further and closer examination.

Seasonal Mean Levels of Heavy Metals in Water and Associated Sediments from Ajawere River in Oke-Osun Farm Settlement, Osogbo, Nigeria

J. A. O. Oyekunle — 2012-04-05

The seasonal mean variations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn in the water and sediments of Ajawere River in Oke-Osun Farm Settlement, Osogbo, Nigeria were evaluated. Samples collected were analyzed for their heavy metal levels using Graphite Furnace Atomic Absorption Spectrophotometer (GF-AAS). Seasonal mean ranges of heavy metals in the river sediments (mg/kg) were 3.39 ± 1.34 Cd to 43.24 ± 6.15 Cr in the rainy season and 4.56 ± 1.21 Ni to 55.35 ± 4.29 As in the dry season. Seasonal mean levels of heavy metals (mg/L) in the river water ranged between 3.02 ± 0.72 As and 179.49 ± 21.45 Fe in the rainy season while the dry season mean levels ranged from 3.09 ± 1.65 Co to 278.81 ± 51.59 Fe. Wide seasonal variations were observed for Cr, Cu, Mn, Ni, V and Zn in the sediments and for all the other metals apart from As, Ni and V in the water samples. The I-geo values obtained indicated that the sediments were moderately polluted with respect to Cr, Cu and Pb, and was either heavily polluted or very heavily polluted with respect to As and Cd. Metal levels in the river water, in many cases, were above the specified guideline limits for natural waters. The results obtained from this study indicated that the river sediment and water samples from Oke-Osun Farm Settlement were contaminated with heavy metals in varied degrees and gave cause for concern.

Soil Moisture Distribution Pattern and Yield of Jute Mallow (corchorus olitorius) under Three Different Soil Fertility Management

A. T. Ogunrinde — 2012-04-05

Field experiment was conducted to determine the soil moisture distribution pattern and yield of Jute mallow (Corchorus olitorius) in a sandy clay loam soil of the tropical rain forest of Akure, Nigeria, under three different soil fertility management. The treatments were: zero fertilizer application plus rain fed condition (control); 1.79 ton ha^-1 of poultry manure plus rain fed condition; 0.54 ton ha^-1 of urea fertilizer application plus rain fed condition. The three treatments were replicated three times in a completely randomized block design. During the period of the plant development, the moisture content of the soil increases with increase in the depth of the soil. The highest mean value for the depth of the water stored occurred in the plots under urea treatment with value 9.243 ± 2.96 cm. Measured plant parameters showed the best Corchorus olitorius yield components in plots under urea treatment. The mean plant height at 6 weeks after planting (WAP) was 106.13 ± 5.55 cm, mean number of leaves at 7WAP was 54.90 ± 6.71, while the mean leaf area and leaf area index at 6WAP were 572.26 ± 7.53 mm² and 0.16 ± 0.02, respectively. Biomass yield at 4 WAP was 1.99 ton ha^-1 for plants in urea treated plots, 1.577 ton ha^-1 under poultry manure and 1.445 ton ha^-1 in the control experiment. There was no significant difference between the yields of the different treatment plots during the early stage of the plant development. The organic matter content was 2.1%, 2.15% and 2.25% in treatment plot under urea application, poultry manure and control experiment respectively. The nitrogen (N) content were 1.3%, 1.5% and 1.4% in treatment plots under urea, poultry manure plot and the control experiment respectively. Magnesium (Mg) content of treatment plots were 2.50 cmol kg^-1, 2.65 cmol kg^-1 and 2.70 cmol kg^-1 in plots under urea, poultry manure and the control experiment, respectively. At 7 WAP, the total biomass yields were 6.78 ton ha^-1, 5.58 ton ha^-1 and 3.27 ton ha^-1 for plants under urea and poultry manure application and control, respectively. The urea fertilizer and poultry manure applied, improved the chemical properties of the, soil which led to the significant increase in the biomass yield of the plant.

Spatial Variation of Acid Rain and its Ecological Effect in Nigeria

S. I. Efe — 2012-04-05

The study is aimed at examining the spatial variation of acid rain and its ecological consequences in Nigeria. The study covers Nigeria. A total of two hundred and twenty eight rainwater samples were collected; an average of nineteen samples per month. The water samples were analysed in the laboratory and multiple regression analysis used to ascertain the level of variation and relationship with distance from the source of gas flare. Results of the Hydro chemical analysis revealed moderately low pH values of <4.99 for rainwater sources in Nigeria. The pH values however decrease from the north to the south. Also the pH value of rain water samples correlated significantly (r = 0.97) with latitudinal variation and is ascribed to the influence of gas flaring and other anthropogenic activities carried out in the Nigeria environment. There is the intrusion of acid rain into other sources of water, which led to mild acidity of these water sources in Nigeria. The need to extinguished gas flaring is recommended and Nigeria should embrace environmental laws and policies in order to adapt to the changing environment.

Hydraulic Conductivity and Infiltration of Soils of Tropical Rain Forest Climate of Nigeria

I. E. Olorunfemi — 2012-04-05

Hydraulic conductivity (K_θ) is the single most important hydraulic parameter for flow and transport-related phenomena in soil. In this study, the effects of soil moisture contents, soil bulk density (BD), total porosity (PT), soil water holding capacity (WHC), organic matter content, and cation exchange capacity (CEC) on hydraulic conductivity of various sized aggregates of horizon A (0 – 20 cm soil layer) in five major cities (Ibadan, Ife, Akure, Owo and Ado-Ekiti) of the tropical rain forest zone of Nigeria was investigated. Hydraulic conductivity was determined by a steady-state flow using an infiltration device (mini-disk infiltrometer). Suction rates of 2 cm s^-1, 3 cm s^-1, and 4 cm s^-1 were chosen at different locations on the fields for the infiltration measurement and subsequent estimation of soil hydraulic conductivity. At 2 cm s^-1suction rate, the mean value of K_θ ranged from 0.0022 ± 0.001 cm s ^-1 to 0.00071 ± 0.0004 cm s ^-1. The highest and lowest mean bulk densities 1.5 g cm^-3 and 1.33 g cm^-3were observed in soils of Ife and Akure, respectively. Similarly, mean total porosity values ranged between 0.44 cm³cm^-3 and 0.5 cm³cm^-3. Statistical relationship between the total porosity and hydraulic conductivity gave a high correlation coefficient, r = 0.94 at p < 0.05. The correlation coefficient (r) between water holding capacity and hydraulic conductivity was 0.95. Results shows that Soil physical properties such as bulk density, total porosity and water holding capacity affect water infiltration characteristics of soils of the study area.

Interpretation of Observed Surface Ponds Water Quality using Principal Components Analysis and Cluster Analysis

A. O. Ayeni — 2012-04-05

Varieties of approaches are being used to interpret the concealed variables that determine the variance of observed water quality of various sources. A considerable proportion of these approaches are statistical methods, multivariate statistical techniques in particular. The use of multivariate statistical techniques is required when the number of variables is large and greater than two for easy and robust evaluation. By means of multivariate statistics of principal components analysis (PCA) and cluster analysis (CA), this study attempted to determine major factors responsible for the variations in the quality of 30 surface ponds used for domestic purposes in the 6 selected communities of Akoko Northeast LGA, Ondo State, Nigeria. It classifies the samples’ location into mutually exclusive unknown groups that share similar characteristics/properties. The laboratory results of 20 parameters comprising 6 physicals, 8 chemicals, 4 heavy metals and 2 microbial from the sampled ponds were subjected to PCA and CA for further interpretation. The result shows that 5 components account for 97.52% of total variance of the surface pond quality while 2 cluster groups were identified for the locations. Based on the parameters concentrations and the land uses impacts, it was concluded that domestic and agricultural waste strongly influenced the variation and the quality of ponds in the area.

Multivariate Statistical Analysis for the Assessment of Hydrogeochemistry of Groundwater in Agbabu Area, S.W. Nigeria.

T. H. T. Ogunribido — 2012-04-05

Investigation into the hydrogeochemistry of groundwater in Agbabu Area in S.W Nigeria using physical and chemical parameters has been carried out. Samples were collected from eighty water points, comprising fifty two samples in the dry season and twenty eight water samples in the rainy season. The physical parameters measured in the field were pH, temperature, electrical conductivity and total dissolved solids. Chemical constituents analyzed for includes, bicarbonate, chloride, sulphate, nitrate, phosphate, calcium, magnesium, sodium, potassium, iron, zinc, copper, chromium, cadmium, lead, arsenic, nickel, total hardness, calcium hardness, manganese, turbidity, alkalinity, oil and grease for groundwater and were determined using established standard method. Descriptive statistics, correlation matrices, factor analysis, together with cluster analysis were used to gain an understanding of the hydrogeochemical processes in the study area. Factor analysis identify six main processes influencing groundwater chemistry which are sea water intrusion, mineral precipitation and dissolution, seasonal changes, cation exchange processes, human activity and decay organic matter. These six factors accounted for 74.6% of total variance of the groundwater.

Impact of Urbanization on Wetland Degradation: A Case Study of Eleyele Wetland, Ibadan, South West, Nigeria

M. N. Tijani — 2012-04-05

Nigeria is richly endowed with both coastal and inland wetlands, many of which are being threatened by anthropogenic drivers such as land use activities, urbanization, agricultural activities in addition to the emerging threats of climate change. Therefore, this study highlights the environmental assessment of urbanization land-use impacts on degradation of Eleyele Wetland in Ibadan SW-Nigeria. For the study, a GIS-based remote sensing assessment was employed to characterize the temporal changes in land-use dynamics within the catchment areas of the Eleyele Wetland. In addition, about 40 water samples (from both the main Lake and feeding streams) and 25 bottom sediments samples were collected and subjected to chemical analyses of the major cations and trace metals using inductively coupled plasma mass spectrometer and atomic Emission spectrometer (ICP-MS /-AES) methods respectively. The GIS-based assessment revealed a reduction in the riparian wetland forest of 1.25 km² as at 1984 to 0.70km² by 2004 with a projected decline of 0.42 km² by 2014. These clearly signify considerable impact of human activities with loss of 45-70% of the wetland riparian and light forests due to about 70% increase in build-up areas between 1998 and 2004. The measured physico-chemical parameters of the water revealed relatively higher values in the feeder streams compare to that of the main wetland Lake with pH values of 6.5 to 8.8 and 6.7 to 10.1 and EC of 141 to 1252µS/cm and 142 to 424µS/cm respectively. The average Ca, Mg Na and K concentrations in the lake revealed values of 29.1, 9.3, 29.6 and 13.0 mg/l respectively while those of the feeder streams are 43.9, 9.9, 39.7 and 13.49mg/l respectively. The results of the trace metals such as Cr, Cd, Co, Cu, Pb, Ni, Fe, Al, Mn and Zn also show the similar trend of higher values in the feeder streams over those of the lake samples, a situation which could be attributed to impacts of urban waste water and effluent discharges to the feeder streams. However, the lower concentration in the main lake can be attributed to the dilution effect. The overall results highlight the negative impacts of the human-induced influence on the Wetland ecosystem through land-use and waste effluent discharges with attendant degradation / loss; hence, the need for Integrated Water Resources and Environmental Management in order to safeguard the overall quality of the wetland ecosystem.

WASTE MANAGEMENT AND HEALTH IMPLICATIONS

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Detection of Faecal Coliforms in Biofilms of Water Tankers in Odongunyan, Ikorodu - A Peri-Urban Lagos Settlement

O. N. Olaleye — 2012-04-05

Unavailability of public piped water in Odongunyan- a peri-urban community in Ikorodu Local Government of Lagos State, South West Nigeria compelled the people to seek water from other sources. Water transportation with the aid of commercial tankers is one of the means used to convey water from source to other areas of need within the community without adequate concern to its public health implications. This study investigated the presence of Escherichia coli- an indicator of faecal contamination in the biofilms of thirty water tankers in the community. Of the thirty tankers investigated for E. coli using the membrane filtration technique, all the tankers showed the presence of E. coli in their biofilms. The E. coli counts ranged between 1.3 x 10⁴cfu/cm² and 4.2 x 10⁴ cfu/cm². The total plate counts ranged between 5.1 x 10⁴cfu/cm² and 9.8 x 10⁴cfu/cm² and the pH of the water collected in all the tankers also ranged between 6.54 -7.03. The results showed that the water tankers biofilms are loaded with faecal contaminants and there is need for sanitation legislation at local levels to ensure regular disinfection compliance by commercial water hawkers.

Exploiting the Potentials of Inland Valleys of Nigeria for Poverty Alleviatio

S. O. Adigbo — 2012-04-05

Poverty is steering at the face of most developing countries particularly the Sub-Sahara Africa in spite of the abundance inland valleys which have the potential of growing three crops in sequence within a year without irrigation. Inland valleys show considerable potential for intensification and sustainable land use. The potential impact of this valley is related to the presence of water and total areas covered for the production of many food crops. However, they are only marginally utilized. The paper highlighted the abundance of this high potential natural resource, existing cropping systems in the inland valleys of Nigeria. It further elucidated (1) the potential of inland valley as a highly productive agricultural land source for resource poor farmer (2) the research interventions to increase productivity, and 3) other relevant issues pertaining to resilience of the systems, were reported. The yields of crops in inland valleys are generally much higher than on the uplands. The naturally abound inland valley in Nigeria is a high resource potential for food crop production. It is robust and resilient resource that could support triple cropping systems on sustainable basis without the fear of deterioration. Each component of the triple crops in the inland valley out yielded the single crop in the upland counterpart. Thus, for Nigeria and indeed Africa to be food sufficient, judicious management of wetlands may likely be the pathway to satisfactorily meeting the food supply of teaming population of a continent plagued by poor soils, drought and environmental destruction.

Aflatoxins in Smoked-dried Fish sold in Abeokuta, Ogun State, South-west Nigeria

A. A. Akinyemi — 2012-04-05

This study estimated the aflatoxin contamination of smoked-dried fish samples of Alestes nurse (Silverside fish), Synodontis budgeti (Catfish), Ilisha Africana (West African Shad), Gymnallabes typus (Catfish), Ethmalosa fimbriata (Bonga), Chrysichthys nigrodigitatus (Siver Catfish), Schilbe uranoscopus (Butter fish), Cynoglossus browni (Sole), Clarias gariepinus (Mud Catfish), Calamoichthys calabaricus (Rope fish) in Abeokuta, Ogun State, Southwestern Nigeria. Fifty smoked-dried fish samples sold at two different markets in Abeokuta town, Lafenwa and Itoku in Abeokuta, Ogun State, Nigeria were found to be lightly contaminated with aflatoxin (P<0.05), after testing for their aflatoxin levels using Veratox quantitative aflatoxin test. The aflatoxin concentrations in the samples were between 0.030ppb-1.150ppb with a mean of 0.5980±0.1050 ppb. Rope fish had the lowest aflatoxin concentration while Mud catfish had the highest aflatoxin concentration. Aflatoxins are known to be carcinogenic (causing hepatoma – cancer of the liver), acute hepatitis, reduced red blood cell and decreased immune system in man. Prolonged intake of smoked fish with these metabolites may constitute potential public health hazard. Smoked-dried fishes stored for sale in Abeokuta markets were not heavily contaminated with aflatoxins.

Earthworm as Bio-indicator of Heavy Metal Pollution around Lafarge, Wapco Cement Factory, Ewekoro, Nigeria

O. T. Olayinka — 2012-04-05

Heavy metal pollution of terrestrial and aquatic ecosystems has long been recognized as a serious environmental concern. The use of earthworm as bio-index of soil heavy metal pollution was hereby examined. Using the Lagos/Abeokuta express road as transect, four replicates each of soil and earthworm samples were collected from five points: 100m north, 500m south, 1000m north, 1000m south, 2000m north of the Lafarge WAPCO cement factory, Ewekoro and a sixth point at the Arboretum, University of Agriculture, Abeokuta (control site). Using spectro-photometry method, heavy metal concentrations (Pb, Cu, Mn, Zn, Cd, Co) were measured in all samples of soil and earthworm. Histological studies were conducted on earthworm sections. All data obtained were subjected to analysis of variance and post hoc tests to establish significance at (p<0.05). Heavy metal concentrations in earthworm and soil decreased significantly (p<0.05) with increasing distance from the factory. The heavy metal concentrations in soil and earthworm around the factory were significantly higher than that obtained at the control site (P<0.05). Histological studies on the earthworm body wall revealed dark spots and patches on the tissues of the earthworm samples collected from the cement factory area compared with clear earthworm tissues at the control site. Bioaccumulation of heavy metal in soil and earthworm was noticeable around West Africa Portland Cement factory, Ewekoro, Nigeria and could serve as a possible bio-index of heavy metal pollution.

Tertiary Hospital Wastewater Treatment using Reed Bed Technology Planted with Vetiveria nigritana benth and Phragmites karka retz

A. A. Badejo — 2012-04-05

Tertiary hospital wastewater in Nigeria constitutes a risk to public health due to inadequate treatment. Reed bed technology using locally available macrophytes holds tremendous potentials for biological wastewater treatment. The use of Vetiveria nigritana and Phragmites karka in CW for the removal of organic and inorganic pollutants from tertiary hospital was therefore investigated. Characteristics of wastewater such as pH, Nitrates (NO₃^-), Phosphates (PO₄^3-) and Ammonia (NH₃) contents, Suspended Solids (SS), Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO) from the University College Hospital, Ibadan were evaluated using American Public Health Association’s (APHA) methods. The optimal dilution ratio of wastewater was determined by varying wastewater concentration (3:1, 1:3, 1:1, 4:0 and 0:4 wastewater to water) while monitoring growth rate of the macrophytes. Four 3.1 x 3.4 x 0.7 m Reed bed prototypes with Vetiveria nigritana and Phragmites karka planted on 0.2 m deep, 10-15 mm sized granite overlaid by 0.2m washed sand and control bed were evaluated. Composition of wastewater displayed considerable variability (pH 7.5 ± 0.3, NO₃^- 2 ± 0.1mg/L, 3 PO₄^3- 3.9 ± 2.5mg/L, NH₃ 19.5 ± 6.3mg/L, SS 204.1 ± 23.9mg/L, DO 0.9 ± 0.8 mg/L and BOD 310.6 ± 29.9 mg/L). The 1:3 waste water to water dilution ratios supported the most rapid growth of macrophytes. The prototype reed bed showed reduction of BOD 82.0% and 85.0%, TDS 72.0% and 73.0%, PO₄^3- 78.0% and 81.0%, NO₃^- 61.0% and 65.0% for V. nigritana and P. karka respectively. Vetiveria nigritana and Phragmites karka were found to be efficient in wastewater treatment using Reed bed Technology.

Assessment of Impact and Safety Status of Remediation of Lead Contaminated Soil using Excavation Method: A Case Study of Olodo, Ibadan, Southwestern Nigeria

I. A. Oyediran — 2012-04-05

This study aimed to assess the impact and safety status of the excavated waste site of a lead-acid accumulator factory. Soil samples (3 each) were collected from the five pits of depth 1 m each at four angles and one at the centre of the site at interval of 0.5 m. Five soil samples were also collected from five different locations outside the site as a control. All the samples were analysed after pulverisation and digestion using AAS analytical instrument for major, trace and heavy metals such as, Ca, Mg, K, Na, Mn, Cu, Fe, Zn, Co, Cr, Cd, Pb and Ni. Ten water samples were collected, four from shallow hand dug well and six from surface water around the site, and analysed for major ions and trace metals. Using Hakanson (1980) approach, contamination factor of Mn, Zn, Cr and Ni showed low to considerable contamination in A and C-horizon but low contamination factor in B-horizon. This is probably due to the fact that B-horizon could be more porous which served as medium for leaching into C-horizon. Fe, Cu, Cd, Co and Pb revealed considerable contamination factor to very high contamination factor which increase from A-horizon (surface soil) through B to C-horizon (subsurface soil). Degree of contamination show the soil is highly contaminated from top soil through B to C-horizon. Surface water revealed higher concentration of Pb, Cd and Fe in samples from the downstream of the dumpsite which could be due to wash-off by erosion into the rivers.

Distribution and Effect of some Heavy Metals in Selected Organs and Tissues of Albino Rats Exposed to Vehicular Exhaust Fumes

O. A. Ajayi — 2012-04-05

Vehicular exhaust fume has been greatly implicated as one of the major environmental pollutants all over the world, especially in developing nations. A study was carried out to investigate heavy metals distribution and effect on the soft tissues of Albino rats placed in close proximity to busy roads in Abeokuta. A total of 45 rats were randomly allotted to 3 groups of fifteen rats each. Two groups were placed in close proximity to busy roads while the third group (Control) was kept in Forestry Nursery of the University of Agriculture, Abeokuta Ogun State for 8 weeks respectively. The various organs were removed, digested by standard procedures and analyzed for heavy metals (Fe, Cr, Mn, Zn, Pd and Co) with Atomic Absorption Spectrophotometry. The result show a significantly higher concentration of heavy metals (Fe, Mn, Zn, Pd and Co) (p<0.05) in the lung, heart and liver tissues of the rats at busy roads compared to control. Histopathological examination of internal organs (heart, lung, kidney and liver) of rats at busy roads revealed histopathological damage as compared to the control. The results above indicated that vehicular exhaust fumes may have adverse physiological effects on the rats and hence humans living in close proximity to busy roads will be predisposed to automobile pollution.

Waste Disposal Site Selection using Remote Sensing and GIS: A Study of Akure and its Environs, Southwest-Nigeria

Y. B. Anifowose — 2012-04-05

Waste disposal has been a serious challenge in Nigerian cities especially as rural-urban migration intensifies. While overwhelming scientific evidences abound that global warming is taking a significant toll on the Earth and its occupants, Nigeria is striving to join other countries in mitigating the effects. One way of intensifying the mitigation is through appropriate and environmentally-friendly waste disposal and management. All manners of wastes are usually disposed of without any serious consideration for the environment. Open incineration is a very common means of waste disposal in developing countries. In spite of the meager contributions of this group of nations to industrial growth, open incineration method of waste disposal hugely adds to the problem of climate change. It has been observed that there is the tendency to dispose wastes indiscriminately and in an uncoordinated manner, thereby resulting in unhealthy environment. In this study, a satellite imagery covering Akure and its environs was analysed using ArcView GIS 3.2a to develop a user interface for selecting a waste disposal site with special emphasis on geologically suitable conditions. This study aims at demonstrating the potential and efficiency of using GIS in selecting sites for the storage of biodegradable solid wastes. Results show suitable areas where landfill sites can be safely and aesthetically located within the study area, putting urban growth rate into consideration.

Evaluation of Sustainable Water Demand in a Coastal Environment using WEAP Model

Z. O. Ojekunle — 2012-04-05

Ogun river basin, located in southwestern Nigeria, is one of the major river basins under the management of Ogun-Oshun River Basin Development Authority. Different water uses, including domestic, commercial, industrial and agricultural takes place within the basin. As population and economic activities increase, water demand also increases, which makes it imperative for water resources planners to take into account the consequent water demand challenges. In this study, Water Evaluation and Planning (WEAP) model is used to evaluate the impacts of possible water demands on the water resources of Ogun river basin up to the year 2020. Two scenarios were simulated: the first concerns the previous and current accounts of water demand in the basin from 2006 to 2011 while the second simulates the future water demand in the basin from 2012 to 2020. The water demand utilization, unmet demand, demand site coverage, supply delivered, stream flows and water storage were analysed for each scenario by integrating various hydrological components, such as hydrological year cycles, precipitation and dams. Each scenario also made key assumptions with respect to the gross domestic product, population growth rate, irrigation efficiency and complementary sources of water. The results of the model for the previous and current scenarios indicate that the water demand for domestic, commercial, industrial and agricultural uses are 4.7 x 10⁹ m³, 9.5 x 10⁸ m³, 6.8 x 10⁸ m³ and 3.4 x 10⁴ m³ respectively while the corresponding values for the total water demand, supply required and supply delivered are 6.7 x 10⁹ m³, 7.7 x 10⁹ m³ and 3.6 x 10⁹ m³, thereby making the unmet total water demand to be 4.1 x 10⁹ m³.The model prediction for the years 2012-2020 indicates that the water demand for domestic uses will be the highest at 5.3 x 10¹⁰ m³. The demand from commercial, industrial and agricultural uses are 1.1 x 10¹⁰, 2.5 x 10⁹ and 1.4 x 10⁹ m³ respectively. The total water demand, supply required and supply delivered are 6.8 x 10¹⁰ m³ , 7.9 x 10¹⁰ m³ and 10 x 10⁹ m³ respectively resulting in unmet total water demand of 6.9 x 10¹⁰ m³, at an average annual rate of 7.7 x 10⁹ m³. The Ogun River therefore, may not be able to satisfy the future water demand of water users in the basin. To reduce unmet demand, waste water treatment, introduction of water meters to check wastage, building of new dams or increasing the capacities of existing ones, groundwater development, information dissemination and development of manpower in the field of water resources are recommended.

Communique

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Acknowledgement

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List of Registered Participants

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