ABSTRACT
This study assessed the impact of open dumpsites on the
quality of groundwater within the vicinity of solid waste dumpsites in
Maiduguri. The problem of rapid urbanization
and poor waste management has resulted in an
increased of hand dug wells with some located within the premises of an open
dumpsites. The mean percentage composition of solid waste at the two
dump sites were earth/garbage (26%), metal (21%), glass (20%), plastic (19%),
polythene (13%), textile (7%), battery (5%) and paper (3%). Soil sampling was
conducted using soil auger for dry and wet season. Total of 34 soil samples and
4 water samples were collected and analysed for physico-chemical
characteristics; turbidity, temperature, total dissolved solids (TDS),
electrical conductivity (EC), pH, nitrate (NO3), dissolved oxygen
(DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), zinc (Zn)
iron (Fe), copper (Cu), cadmium (Cd), chromium (Cr), lead (Pb), arsenic (As)
and manganese (Mn). Particles size analysis was carried out using Bonyoucos
hydrometer method and the texture determined on the USDA triangle. The soil pH
and electrical conductivity was measured using Turbo pH/mV/temp. and EC meter
and the soil BOD was determined using Winkler method from the soil filtrate.
Potassium chloride (KCl) extraction method was used to determine the soil
nitrate (NO3). The heavy metals (Cu, Zn, Mn, Cd, Pb, As, Cr and Fe)
of the soil extracts were analysed using the multi-wave plasma atomic emission
spectrophotometer (MP-AES 4200). The textural class of soil samples analyzed
for dumpsites A and B were sandy loam with mean percentage ranged from 75-77%,
15.25-17.25% and 6.75-7.757% for sand, silt and clay respectively. The mean
concentrations of pH, EC, NO3 and BOD of the soil samples for
dumpsite A and B ranged from 6.8-8.17, 0.2-1.27 ds/m, 0.01-0.24 mg/Kg and
68-1180 mg/Kg in dry and wet season respectively, and all the mean
concentrations were within NES limit for soil quality. The mean concentrations
of Zn, Fe, Cu and Pb for dumpsite A and B ranged from 103-1412 mg/Kg, 3226-9670
mg/Kg, 10.72-55.7 mg/Kg and 8.21-81.4 mg/Kg for dry and wet season
respectively. The mean concentrations of As, Cd, Cr and Mn for dumpsite A and B
ranged from 71-134 mg/Kg, 0.31-2.67 mg/Kg, 24.91-62.5 mg/Kg and 172-474 mg/Kg
for dry and wet season respectively. All the mean concentrations were within
NES limit for soil quality except Zn and As for both seasons, while Cd for wet
season. The concentrations of temperature, turbidity, pH, EC, and TDS ranged
from 24.2- 30oC, 0.28-4.73 NTU, 7.35-9.8, 131-1329 μs/cm and 70-906
mg/l for dry and wet seasons respectively. All the concentrations were within
NSDWQ and WHO standard limit in the dry season except turbidity and pH in the
wet season. The concentrations of DO, COD, BOD ranged from 25-70 mg/l, 150-2000
mg/l, 4-30 mg/l and 1.18-53.62 mg/l for dry and wet seasons respectively. All
the concentrations were above NSDWQ and WHO standard limit except NO3. The
concentrations of Zn, Fe, Cu, and Pb ranged from 0.01-0.122 mg/l, 0.11-0.812
mg/l, 0.011-0.226 mg/l and 0.003-0.3 mg/l for dry and wet seasons respectively.
All the concentrations were within NSDWQ and WHO standard limit except Fe in
the wet season. The concentrations of As, Cd, Cr and Mn ranged from 0.029-514
mg/l, 0.001-0.24 mg/l, 0.001-0.184 mg/l and 0.001-0.357 mg/l for dry and wet
seasons respectively. All the concentrations were above NSDWQ and WHO standard
limit. The results obtained in this study shows that the leachate generated
from the solid waste dumpsites had impacted negatively on the soil.
CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
Groundwater is one of the most important natural resources which
contribute to the global freshwater supply. In Nigeria, groundwater provides
much of the public and domestic water supply, supports agricultural and
industrial economies, and contributes its flow to rivers, lakes and wetlands;
and this helps in maintaining balance in the ecosystem (Aizebeokhai, 2011).
Groundwater is the primary source of potable water in most parts of Nigeria,
particularly in rural areas, which rely on domestic (private) hand-dug wells
(Aizebeokhai, 2011). According to Kumar (2013) despite its reliability, this
precious and vital resource is under increasing threats attributed to above
ground anthropogenic activities related to uncontrolled urbanization, incessant
waste disposal and poor land use management. In addition, the usefulness of
groundwater to humans essentially depends on its chemical status, thus,
assessment of groundwater quality is important for the socioeconomic
development of most developing and developed countries of the world (Kumar,
2013).
Groundwater quality is an important factor in the context of
sustainable water management, the integrity of underlying aquifers is mainly
affected by pollution from above ground sources, particularly solid waste
disposal (Kumar, 2013). Uncontrolled urban growth and its resultant effect,
especially in developing nations like Nigeria, can adversely affect the quality
of underlying groundwater if not properly controlled (Putra and Baier, 2008).
With a rapid population growth of about 2.5% per annum, the demand
for water supply has progressively increased over the last
three decades. The provision of safe drinking water has actually deteriorated -
access in urban areas fell from 55 million people to 27 million people in 2002
in African cities (Jacobsen et al., 2012). This is largely due to poor
management, inadequate technical capabilities, lack of investment and
insufficient manpower and their training (Hanidu, 1990). Furthermore, the
institutions responsible for water supply in Nigeria are both ineffective and fragmented;
thus, a transition is needed to bring about a thorough and holistic change to
the current system (Jefferies and Duffy, 2011).
Solid waste dumpsites which have been identified as one of
the major threats to groundwater resources receive a mixture of municipal,
commercial and mixed industrial wastes. Moreover, studies on the effects of
unlined waste dumps on the host soil and underlying shallow aquifers have shown
that soil and groundwater systems can be polluted due to poorly designed waste
disposal facilities (Amadi et al., 2012). Groundwater contamination in a
dumpsite facility occurs mainly due to the contaminant potential of leachate
from the waste body. These leachates are solutions, essentially organic or
inorganic complexes of biodegradation components of solid wastes flowing from
the refuse dumps, saturated with rainwater (Kassenga and Mbluligwe, 2009).
As reported by Sankoh et al. (2013) open dumpsite approach as
solid waste disposal method is a primitive stage of solid waste management in
many parts of the world. It is one of the most poorly rendered services by
municipal authorities in developing countries as the systems applied are
unscientific, outdated and inefficient. Moreover, solid waste disposal sites
are commonly found both within and on the outskirts of developing urban
cities. According to Nguyen (2011), many cities in developing
countries face serious environmental degradation and health risks due to the
poorly developed municipal solid waste management system. The compositions of
municipal solid wastes are influenced by certain factors, which include the
area (residential and commercial), the economic level (differences between high
and low income areas), the season and weather (differences in the amount of rainfall
in a year and duration) and culture of people living or doing business in the
area (Napoleon et al., 2011).
1.2 Statement of Research Problem
The problem of rapid urbanization has lead to increase in
municipal solid waste generation because of increasing population and some
socio-economic factors in Nigeria. (Butu and Mshelia, 2014). Majority of the
municipal solid waste disposal sites in Nigeria are still open dumps. Moreover,
in most cases the landfills are not properly engineered and operated to accepted
world standards. Improper management of solid waste areas has resulted in
serious ecological, environmental and health problems. Such practices
contribution to widespread environmental pollution as well as spread of
diseases (Susu and Salami, 2011). Solid waste disposal by landfill poses a
threat to groundwater and surface water quality through the formation of
polluting liquids known as leachate (Mohammed et al., 2013). Although
groundwater quality within the aquifer varies, it is of high quality on the
average, with some decline from south to north in Nigeria. Total dissolved
solids are high in the Pliocene aquifer of Chad basin formation. Investigations
of water quality in the Upper, the Middle and the Lower aquifer in the
Maiduguri area (Nigeria) have found considerably high concentrations of
fluoride (BGS, 2003).
According to Kola-Olusanya (2011) the risk of groundwater
pollution is increasing both from disposal of solid waste and the widespread
use of potentially polluting chemicals in agriculture. In this study the
problem of acute water supply has resulted in the rapid increase of hand dug
wells with some located within the premises of an open dumpsites in Maiduguri.
This negative impact is significant in some of the areas within Maiduguri where
tons of residential and commercial solid wastes were inappropriately dumped.
These problems potentially pose a significant threat to the upper unconfined
aquifer system of the Chad Basin around Maiduguri and this aquifer is the major
water supply source for the city. This consequently poses health risks to the
local population, more especially the urban poor who largely depend on the
groundwater without any form of treatment (Bakari, 2014).
1.3 Significance of the Study
Understanding the quality of groundwater is a very important
factor in determining whether the source could be used to supply suitable water
for human consumption and use. As a scarce resource, groundwater requires
continuous monitoring through quality assessments and management for
sustainable use against contamination. Groundwater is the primary source of
potable water in most part of Maiduguri metropolis, which relies on domestic
(private) hand-dug wells from the upper aquifer (Bakari, 2014). The ability for
municipalities, particularly Maiduguri to ensure reliable protection of public
health and the environment through efficient wastes management, there is a need
to identify a relationship between the solid waste, soil and groundwater that
will help to understand the quality of the groundwater reservoirs in the study
area. This study will provide useful knowledge on water quality awareness to
reduce problems associated with water and its
implications on health related risks. Application of quality
assessments of groundwater in Maiduguri area has important implications in the
groundwater‟s potential as a resource and can indicate where negative impacts
may be mitigated and efficiency of water conservation programs can be
evaluated.
1.4 Aim and Objectives of the Study
The aim of this study is to conduct a water quality
assessment on some selected wells within the proximity of an open dumpsite in
Maiduguri with the following objectives;
i. To determine the composition of the solid wastes.
ii. To evaluate the Biophysico-chemical characteristics of the
soil at the open dumpsites.
iii. To evaluate the physico-chemical characteristics of the well
water near and way from an open dumpsites.
iv. To compare the physico-chemical characteristics of the soil
and water samples with National Environmental Standard of soil quality (USEPA)
and NSDWQ and WHO standard limit of water quality,
v. To determine the water quality index of the water samples
using Weighted Arithmetic Water Quality Index Method.
1.5 Scope and Limitation of the Study
The research work is mainly on groundwater quality of well in
relation to municipal solid wastes in Maiduguri. Two dumpsites at Kumshe and
Bakasi were identified to examine the characteristics of solid wastes,
physico-chemical characteristics of soil at the dumpsites and physico-chemical
characteristics of the wells within the proximity of the dumpsites. The time
frame for this research was conducted for eight months within which
the assessment of solid waste composition, soil samples
within the dumpsites and water samples for both the dry and wet seasons were
carried out. The research is limited to soil characteristics as leachate in
able to obtain from the dumpsites.
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