ASSESSMENT OF THE EFFECTS OF DUMP SITE ON GROUNDWATER QUALITY IN BARIKIN-SALE, MINNA NORTH-CENTRAL, NIGERIA

ABSTRACT

Discharge of leachate from refuse dumpsites is a source of groundwater pollution within its immediate environment of location. Geophysical investigation of an uncontrolled open solid waste dumpsite located at Barikin-Sale area of Minna was carried out for possible contamination of groundwater.   The investigation was aimed at delineating groundwater contamination due to leachate percolation thereby assessing the quality of groundwater from hand dug wells and boreholes within the dumpsite and the surrounding environment. A total  of  ten (10) Vertical  Electrical  Sounding  (VES) points  with  maximum  current electrode spacing of 20 m and two (2) 2D Subsurface Electrical Imaging were investigated within and outside the dumpsite to assess leachate migration in the area. Schlumberger configuration was used for the VES while the Wenner configuration was used for the subsurface imaging. The VES data were analysed and a maximum of three (3) geoelectric sections were identified; the top soil, weathered basement and the fractured/fresh basement. The obtained apparent resistivity for those layers were between 19.4 Ωm and 122.6 Ωm for the first layer, 18.2 Ωm and 33.4 Ωm for the second layer and 93.5 Ωm and 166.4 Ωm for the third layer respectively. The range of thickness for the first layer is 0.9 m and 1.8 m and for the second  layer are 4.0  m  and  5.3  m  respectively.  The 2D resistivity data  were processed and inverted using the RES2DINV software. The inverse resistivity models of the subsurface from the 2D subsurface electrical imaging revealed low resistivity value <20 Ωm which is taken to be leachate derived from decomposed waste while these wastes that cannot decompose are occurring as isolated parts with slightly higher resistivity value of >20 Ωm. The areas with the highest resistivity value of >100 Ωm were further interpreted to be chemical weathering product of crystalline bedrock considered to be regolith. Sieve analysis of sixteen (16) soil samples from four (4) pits was carried out; the result shows that the soils are fine to medium sand and the hydraulic conductivity was computed from it using the HydrogeoSieveXL software. From the estimated hydraulic conductivity (K), the values range between 1.97 x 10-4 and 2.52 x 10-5 m/s. This further clarifies the geophysical investigation results. The physicochemical analyses of ten (10) water samples from hand dug wells and boreholes were carried out. The results show that the median and mean concentration of conductivity at 1290 µs/cm and 1616 µs/cm, TDS at 864.5 mg/l and 1078.7 mg/l and nitrite at 0.039 mg/l and 0.4929 mg/l all exceed the permissible limits of 1000  µs/cm,  500  mg/l  and  0.2  mg/l  of  NSDWQ  (2007)  and  WHO (2010)  indicating groundwater contamination. Although, at some locations the analysed parameters exceed the permissible limits but their median and mean concentrations are generally inside the permissible limits. From the results, it could be concluded that leachates are concentrated within the lower part of the dumpsite; therefore the surrounding environment groundwater sources are vulnerable to leachate contamination from the dumpsite.

CHAPTER ONE

1.0      INTRODUCTION

1.1       Background to the Study

Groundwater forms an important part of the water resources across the world particularly in the arid regions. It is used for household functions because it is of high quality and require slight or no remedy prior to usage. According to Martins (2001), bacteria, fungi and other biological  contaminants  are in  nature  filtered  and  attenuated  as  the  water infiltrate  or permeate across the soil.  Another reason why groundwater is made use of domestically is that the providing clean water through the scheme of water made available is hideously insufficient for the requirements of the public.   The result of lackadaisical management and/or  discarding  of  hazardous  materials  have  greatly  decreased  fresh  groundwater supplies.   The setback of ecological contamination is a major concern of earth scientists today, and investigators from other associated disciplines across the world.

According to Ige (2013), there is disproportionate increase in waste generated in Nigerian cities with increase in social-economic development. Rapid industrialization and the unrestrained escalation of the city population effect in the creation of substantial noxious solid remains. Municipal desecrate items, principally household trash, are habitually thrown away improperly on surfaces of land, superficial excavation, drainage, channels of river and stream thus making the groundwater susceptible to pollution. Solid trash landfills represent an essential piece of the hydrological structure of the soil (Rosqvist et al., 2003), therefore poses a severe danger of infecting mutually the groundwater and the surface water downstream.  Therefore,  there  is  need  of  understanding  and  quantifying  the  landfills hydraulic behavior.  Groundwater pollution happens generally as a result of the percolation of  fluvial  water  and  the  penetration  of  pollutants  into  the  soil  underneath  a  garbage dumping sites.  The noxious waste is a liquid resulting from the putrefaction of municipal solid wastes.   Contamination takes place when the leaking aqueous liquid, known as the leachate reaches the groundwater table, consequently affecting the quality of the groundwater. The ecological contamination and healthiness risk related to exposed dumpsites cannot be overemphasised (Aderemi et al., 2011).

United Nations Environment Programmed (UNEP, 2002), said that 0.5 kg of solid trash is generated by each person daily on the average.   Accordingly, in Barikin-Sale area, the municipal waste and refuse generated daily are in thousand metric tonnes.  The Barikin- Sale waste disposal site is an open dump type (it has no top protector which stop rain water from inflowing forming leachate and base coat to avoid the leachate departure in the site of waste dump), and it is situated between populated residential areas which consequently creates severe problems to local ecological value and community health.   As a result, Barikin-Sale area might encounter serious crisis of contamination of groundwater assets in future if the dilemma of indiscriminate dumping of waste at the dumpsite is not sufficiently tackled.

An essential frequent need in city areas includes identifying the locality and degree of pollution spaces in laces occupied by landfills.  Within this context, applying geotechnics, hydrogeology and geophysical approaches gives a significant means in the estimation and categorization of pollutants created by urban remains (household and/or industrial).  

The particle size grading of soils underlying the dumpsite will give an insight into the rate of movement  and  percolation  of leachates  across  the area.  Geotechnics  and  geoelectricalmethods have been found very appropriate for such type of ecological studies.  

This is because usually, ionic intensity of leachate from landfill is a lot beyond that of groundwater and thus as soon as the leachate penetrates the aquifer, a great difference in electrical properties will be experienced and the methods will recognize these regions as an irregularity and it allows the detections of the leachate trail. The use of geology, hydrogeology, geotechnical and geophysical methods as used in the studies of landfills are documented properly (Ige et al., 2011; Rowe, 2011; Porsani et al., 2004; Karlik and Kaya, 2000; Mukhtar et al.,2000, Fatta et al., 2000 and Benson et al., 1997).

The setback of environmental contamination is a major concern of planet scientists today, and investigators from associated area of study all over the globe. Haphazard dumping of untreated garbage is harmful to health since it produces unhygienic surroundings which have bad effects for city inhabitants. Wherever sanitary services are in short supply, domestic solid garbage is likely to be combined with fecal material; thereby complexing the health risks. Most of these waste disposal sites are located in open spaces within the vicinity of human settlements where several wells and boreholes are found. Indiscriminate dumping and inappropriate managing of household and industrial wastes will affect harmfully the environment and wellbeing of the inhabitants. Transmittable infections associated with deprived ecological setting exterminate one in every five African children, with acute respiratory diseases and diarrhea as the two main cause of death (WHO, 1979). Ailments like typhoid, cholera, guinea worm, trachoma, bilharzias, polio, hookworm, and tapeworm are related to drinking of poor quality water and sanitation (Boadi and Kuitunen, 2005). As a result of industrial advancement and urbanization in recent time, there is tremendous increase in the population of people living in Barikin-Sale, and this has led to exceptional  increased  in  the  waste  generation,  therefore  refuse  dumpsites  become  a common feature in the city.

Groundwater contamination within a waste disposal site results from the infiltration of leachates through the soil. The leachates are created once rain falls on the landfill site, percolate into the garbage and carries pollutants as it leaches down (Egbai et al., 2015). The frequent thin aquifer found in the environments of basement complex is typically opened to external and near-external pollution (Aweto, 2011). Having been affirmed that immediately an aquifer is extremely exhausted or polluted, the harm is basically unending and pains to remedy the pollution are exceptionally expensive (Jegede et al., 2013). Within the study area and the surrounding environs, groundwater is gotten from boreholes and wells (hand- dug) at depths occasionally as thin as 5 m as the major supply of water for household uses in the area. The contamination becomes obvious resulting from the hydraulic link relating the harmful substances of the groundwater and leachate plumes (Nasir et al., 2010).

Basically, two distinctive methods can be used in investigating the level of contaminants in groundwater. Firstly, the destructive method which requires sampling utilizing soil auger/core sampler in which case the area’s geology is constantly altered. Secondly, the non-destructive method which makes use of geophysical method where the geology of the area is not disturbed (Oyedele, 2009). One of the recognized geophysical methods is the electrical resistivity method which gives beneficial and non-devastating course to recognize delineate and map the sub-surface defining leachate contaminant plumes from dumpsites. This method is based on leachate electrical conductivity which is likely to be above that of groundwater (Cristina et al., 2012). Researches have also proven that resistivity method is a tool for identifying, delineating and mapping of leachate contaminant plumes (Cristina et al., 2012; Porsani et al., 2004; Meju, 2000 and Loke, 1999;).

Direct Current (DC) electrical resistivity techniques of exploration geophysical are trendy and have proven to be thriving and dependable in the areas of geo-environment, hydrogeology, engineering’s and contaminant hydrology. Lately, a recent improvement is in the application of 2-D techniques of electrical imaging to map places having moderate to difficult geology (Griffths and Barker, 1993). Also, mapping of changes in the recorded resistivity in the vertical and also the horizontal trend, gives a more precise pattern of the underground in two-dimension (2-D). Electrical resistivity methods for contaminant studies have a broad range of function on thin resources of groundwater, and the advantages include the reduction in the require for intrusive methods and complete sampling, produces intrinsic properties (electrical conductivity/resistivity) of groundwater chemistry that gives information on contamination, reasonably economical, and optimization of the requisite amount of observation wells (Ebraheem et al., 1990; and EL-Mahmoudi, 1999). The objective of the study is to apply geoelectric technique implementing the vertical electrical sounding and the 2-D subsurface electrical imaging (2D resistivity tomography), employing the Wenner techniques to identify and outline leachate trail from an uncontrolled solid trash disposal site in Barikin-Sale Minna, North-central Nigeria.

1.2       Statement of the Research Problem

Water is a fundamental requisite of human and industrial development and it is the main fragile piece of the surroundings (WHO, 2010). Hence, a nonstop observation of quality of water is extremely necessary to ascertain the status of effluence in our rivers, hand dug wells and boreholes. Every human on earth has the tendency to generate waste, but the management of the waste produced has constantly posed a challenge to the society at large, mostly in developing nations such as Nigeria. The indiscriminate disposal of waste has seriously added to environmental degradation.

Contamination of water by bacteria and trace metals is a significant feature in equally environmental health and geochemical cycling of metal. Trace quantities of heavy metals are constantly existing in fresh waters of terrigenous supplies for example rock weathering which result to geochemical re-cycling of elements of heavy metal in these ecological units (Amadi et al., 2015). When the waste disposal site is not situated on an appropriate earth, it might allow the permeation and relocation of waste produced leachate into the resources of groundwater thus changing the water attribute harmfully. City waste resources, largely household trash, are frequently disposed off on surface ground, thin excavation, stream and river drains  which  put  the groundwater at  extreme  threat  of being  contaminated.  The significant increase in human population is apparently associated with the corresponding generation of huge amount of solid waste resulting from socio-economic activities within the metropolis. Solid trash landfills represent a vital element of the soil hydrological structure (Rosqvist et al., 2003), therefore, poses a severe risk of contaminating together the subsurface and downstream surface water.

1.3       Justification for the Study

Groundwater is the major supply of potable water within the Barikin-Sale area and efforts should  be  geared  towards  protecting  it  from  contaminants.  latest  detections  of  many noxious chemicals in groundwater in the United States of America as a result of municipal solid waste leachate accumulation shows that 32 natural chemicals initiate cancer, 13 result to  birth  defects,  22  hereditary  effects  whilst  around  10  inorganic  chemicals  instigate ailments  such  as  nervous  systems  defects,  cancer of the bladder, kidney/liver  defects, central nervous system defects, circulatory system defects, and skeletal impairment US environmental protection agency (EPA,1994).

Furthermore, the World Health Organization (WHO) 1996 fact sheet no.112 projected universally that no less than a child died from a water connected illness each eight seconds and that annually over five million persons died from sicknesses connected to insecure intake water or poor hygiene. Ecological degradation and pollution of groundwater possibly owing to leachate produced from exposed dumpsites and several human actions (Oyediran and Iroegbuchu, 2013 and Amadi, 2009). The far recognized technique for solid waste dumping  that  requires  a  least  endeavor  and  expenditure  in  Nigeria  is  the  exposed dumpsites. Obstacles to such facilities are moderately obvious, particularly to those possessing the adversity of living near the dumpsites. Open dumpsite does not only pollute groundwater, they are also unattractive, unhygienic, and in general stinking.

1.4       Study Area

The location is Barikin-Sale area of Minna headquarters of Niger State (Figures 1.1). It is bounded by longitudes 6º 31′E and 6º33′E of the Greenwich Meridian and latitudes 9º34′N and 9º36′N of the Equators and the dumpsite is located within the area.

The investigated section lies in the Nigerian Basement Complex topography. This environment is illustrated by three lithofacies: i. the older granites, ii. the low metasedimentary schist and iii. the migmatite gneiss complex (Oyawoye, 1972 and Rahaman, 1976). Significant to the section is the granite-gneiss, granite and schist with residue of quartz trace and pegmatite’s as slight incursions fundamental to the area. Rocks of granite occupy almost 95 % of the section in study. The rocks are generally uncovered on the western segment of Minna Township. It appears as elevated batholiths that are broad in dimension. The granite exposures are foliated, fractured and jointed.

The rocks are comprised of minerals that are bright and dark in colour; quartz, feldspar and biotite-mica correspondingly. The mineral colour alteration describes the gneissose bands.

In  several  circumstances  the  rocks  are  fractured  and  weathered.  The  quartzite  and pegmatites veins appearing as small mineral invasive rock as well outline some part of the region. The rocks of granites and gneisses largely function as the mass rock on which the veins of quartzite and pegmatite minerals. They are delineated by coarse textures. In terms of minerals, they are made up of feldspars, quartz and various valuable minerals of prominent value which consist of aquamarine, emerald, epidotite and tourmaline (Ajibade, 1982 and Wright, 1985). The basement sections hydrogeology is easy given that there is an intrinsic restraint to groundwater occurrences. Although, where there is deep regolith and there are intense systems of fractures, the possibilities for the gathering of groundwater within the rocks of basement complex can raise. Preferably, the region can be separated into two components, that is, the aquiferous region found in the weathered overburden lying on the fresh basement rocks and the area of aquifer inside the extremely fractured systems of joint in the partly weathered basement (Omale et al., 2016).

1.4.1    Relief and Drainage

The relief of the research region is typically level lying, with rather rising and falling ridges contained by the area. There is no most important river that draws off the locale water but there are a number of petite streams running/traversing the region. The structure of drainage in the examined region is structurally restricted. The total streams found in the district are seasonal; they run all through the rainy season and withered as dry season sets in. The outline of drainage of the area can be described naturally as dendritic (Figure 1.2). The elevation of the area ranges from 219 to 245 m (Author’s fieldwork).

1.4.2    Climate and Vegetation

The investigated region  has an archetypal savannah climate with  diverse wet and dry seasons (Ajibade, 1982). The rainy season starts in April and stop within October which is roughly six months phase (Federal Meteorological Agency, Minna, 2011). Maximum of about 1,300 mm and minimum of about 1,000 mm respectively are the annual rainfall distribution pattern of the area. The area’s climate is predisposed by two wind systems, the south-west downpour emerging from the Atlantics.  The subsequent is the dry sandy wind of north-east also known as the “harmattan wind” which emerged from the Sahara Desert. The  maximum  temperature  is  at  (around  35  ºC)  between  March  and  June  and  at  its minimum (about 21 ºC) in December and January (Ajibade, 1982).

The study area flora is grouped in the savannah variety. The savannah plants are deemed as intermediary between the Guinea savannah of northern Nigeria and the southern rain forest correspondingly.  Rainfall reaches  a high  peak  in  August.  Somewhere else,  the  soil  is amenable to the farming of vegetables and other food crops plus foraging by animals.

1.4.3    Settlement and Land Use

The examined region is characterized by a nucleated settlement variety inhabited mainly by the Nupe speaking tribe with other dialect scattered among the population. There are supply of some essential public facilities sometimes such as supply of tap water, electricity and road systems within and communication set-ups. There major source of water supply is hand dug wells and boreholes. The major activities of the people within the area are farming, cultivation of crops like maize, groundnuts, guinea corn, yam and millet.

1.5       Scope the Study

The investigation is structured to assessing the effect of the dumpsite in Barikin-Sale on the groundwater within the area of study. The structure of the work is defining the geology of the area, geotechnical properties of soil samples collected from different locations in the field, geophysical and hydrogeological characteristics of the Barikin-Sale area.

1.6       Aim and Objectives

The  aim  of  the  research  is  to  investigate  leachate  infiltration  pattern  of  Barikin-Sale dumpsite.

The specific objectives of the study are to;

1.    Carry out geologic field mapping.

2.   Delineate the aquifer system and produce hydraulic distribution map.

3.    Determine the hydraulic conductivity beneath refuse dump.

4.    Investigate the behavior of leachate migration in the subsurface.

5.   Determine the suitability of the water for human consumption.

1.7       Regional Geological Setting

The geology of Nigeria is divided into three main litho-petro-stratigraphical units (Figure

1.3). They are the Precambrian aged Basement Complex; the Younger Granite which are

Jurassic and the Cretaceous to Recent in ages Sedimentary Basins.

1.7.1    The Basement Complex

Black (1980) affirmed that the Nigerian Basement Complex (Figure 1.3) resulted from the Pan-African movable belt. It is to the south of the Tuareg Shield, amid the Cratons of West Africa and the Congo. The development of the Basement Complex occurs over no less than events of four orogeny episodes, it consists of 2800 ± 200Ma Liberian, 2000 ± 200Ma Eburnian, 1100 ± 200Ma Kiberan and 600 ± 150Ma Pan-African (Oyawoye, 1972; Rahaman, 1976). The episodes of Liberian, Eburnian and Kiberan were connected to extreme warp and then by regional metamorphism. The Pan-African period of warp was complemented by a regional metamorphism, complemented by the processes of migmatization, granitization and gneisses formation (Abaa, 1983). Regional warp of fracturing and faulting discern the stop of the orogeny.  The Younger Granites of Jurassic age of Jos plateau has abundant ring complexes of calc-alkaline intruding the Basement complex.  The  Basement  Complex  is  overlaid  unconformably  by  the  Cretaceous  and younger sediments at numerous localities inside and all-around Nigeria (Olayinka, 1992 and Obaje, 2009).   Obaje (2009) said the 600Ma Pan-African orogeny influenced the Nigeria basement complex. There was an impact involving the dynamic Pharusian continental boundary and the West African craton inactive continental boundary. The continental impact is thought to be accountable for the Basement Complex creation (Burke and Dewey, 1972). The Basement Complex of Nigeria is illustrated in four petro- lithological sections, this includes;

a.   The Precambrian Older Granite b.   The Migmatite/Gneiss Complex

c.   Undeformed Acidic and Basic Dykes. d.   The Low grade Schist Belt

The stratigraphic succession of the Nigerian Basement Complex is exemplified in Table

1.1.

Table 1.1: Succession of stratigraphy of the Nigeria Basement Complex (McCurry, 1976)

PERIOD             LAYERING                       COMPOSITION

Recent to Tertiary     Surface                 Laterite, clay and alluvial sand-silt

Cambrian to Upper

Precambrian

Metasediment       Phyllite,       quartzite              hornfels, semi-pelticschist, schist amphibolites

Precambrian              Crystalline            Migmatite          complex,          gneiss, feldspalthic quartzite, calcareous schist

1.7.1.1 The Older Granite

The Nigerian older granite (Figure 1.3) intersects the gneiss/migmatite complex and the belts of schist. They are believed to be formed in the magmatic phases that come with the 750–450 Ma orogeny of Pan-Africa. They are made up of broad minerals varieties (Obaje, 2009). The older granite is the mainly distinct of the whole episode of Pan-African orogeny (Rahaman, 1988). Rahaman (1988) classified the suites of the Older Granite on the bases of their petrofabric attribute below.

a) The migmatite granite;

b)  The granitic gneiss;

c)  The early on pegmatitic and fine grained granite;

d)  The uniform to coarse porphyryl granite;

e)  Pegmatitic aplites that are to some extent distorted with veins of quartz; and f)   Undeformed pegmatite, two-micaceous granites and quartz intrusion.

On a universal degree, the older granites are believed to be intrusions of elevated height (Rahaman, 1988).

1.7.1.2             The Migmatite/gneiss Complex

The age of the migmatite gneiss complex varied from 600 Ma Pan-African to around three billion years Eburnean. It is a united component made up series of metamorphosed rocks that are basic and ultrabasic, migmatites, orthogneisses and paragneisses (Obaje, 2009). The migmatite-gneiss mineral composition is considered to being recrystallized by the incomplete melting process that influenced the basement complex. The migmatic-gneiss complex encompasses around 60 % of the exterior area of the Nigerian basement complex. Proof of its domination can be noted in the Nigerian Northwest and North-south (Rahaman, 1988 and Obaje, 2009). The migmatic-gneiss complexes rocks are related to the three main episodes of geological which includes;

a.   Natural  crust  development  and  growth  of  crustal  an  outcome  of  orogeny  and sedimentation 2,500 Ma.

b.   The 2,000 ± 200 Ma Eburnean, manifest by granitic gneisses of Ibadan variety and

c.   The 900 to 450 Ma Pan-African episodes (Rahaman and Ocan, 1978; Rahaman and Lancelot, 1984).

1.7.1.3 The Low Grade Schist Belt

The Nigeria Schist is understood in age as Upper Proterozoic. They are infolded into the complexes of the migmatic-gneiss-quartz (Figure 1.3). They are made up of meta-volcanic and meta-sedimentary rocks of low grade (Obaje, 2009). They are suitably uncovered in the Nigerian western half which trend in the of north-south bearing (Figure 1.4).

Nigerian  northwest  has  been  ascribed  ten  sheet  belts  including  the  Anka,  Kazaure, Kushaka, Kusheriki, Maru, Wonaka, Zungeru-Birnin-Gwari, and Zuru. The Nigerian south western section is ascribed the below sheet belts; Egbe-Isanlu, Ife-Ilesha, Igara, Isheyin- Oyan, Iwo, Kabba-Lokoja (Turner, 1983; Woakes et al., 1987).

1.7.1.4 Undeformed Acidic and Basic Dykes

The acidic and basic undeformed dykes as documented by Obaje (2009) are interrelated to incident  of  Late  to  Post  tectonic  Pan-African  episode.  They  go  through  the  previous elements of the family of the basement complex including; the migmatic-gneiss complexes, the older granites and the belts of schist. The acidic and basic underformed dykes are classified into two categories;

i.    Felsic dykes that are around 580-535 Ma. They are associated to the granitoids of the Pan-African. On a broader level they are connected with rocks and minerals for instance the   pegmatites   influencing   alites,   beryl,   microgranites,   muscovite,   syenite   and tourmaline (Obaje, 2009).

ii.  The basic dykes age is considered to be roughly 500 Ma. They are considered as the youngest element in the Nigerian Basement Complex. They comprise dykes of lamprophite, dolerite and felsite (Obaje, 2009).

₦8,000.00 – DOWNLOAD FULL PROJECT DOWNLOAD FULL PROJECT Added to cart

---

---

---

---

Related Project Topics :