THE IMPACTS OF ANTHROPOGENIC ACTIVITIES
ON GROUNDWATER POLLUTION IN
DERNA REGION, LIBYA
JUMMA ARHOUMA JUMMA ELGALI
UNIVERSITI KEBANGSAAN MALAYSIA
THE IMPACTS OF ANTHROPOGENIC ACTIVITIES ON GROUNDWATER
POLLUTION IN DERNA REGION, LIBYA
JUMMA A RHOUMA JUMMA ELGALI
THESIS SUBMITTED IN FULFILMENT FOR THE DEGREE OF DOCTOR OF PHILOSOPHY
FACULTY OF SOCIAL SCIENCE AND HUMANITIES UNIVERSITI KEBANGSAAN MALAYSIA
BANGI
2013
IMPAK AKTIVITI ANTROPOGENIK KE PENCEMARAN AIR BAWAH TANAH DI WILAYAH DERNA, LIBYA
JUMMA ARHOUMA JUMMA ELGALI
TESIS YANG DIKEMUKAKAN UNTUK
MEMPEROLEH IJAZAH
DOCTOR FALSAFAH
FAKULTI SAINS SOSIAL DAN KEMANUSIAAN UNIVERSITI KEBANGSAAN MALAYSIA
BANGI
2013
|
|
Page |
||||
|
DECLARATION |
iii |
||||
|
ACKNOWLEDGEMENTS |
iv |
||||
|
ABSTRACT |
v |
||||
|
ABSTRAK |
vi |
||||
|
CONTENTS |
vii |
||||
|
LIST OF TABLE |
x |
||||
|
LIST OF FIGURES |
xii |
||||
|
LIST OF PHOTGRAPH |
xiv |
||||
|
LIST OF ABBREVIATIONS |
xiv |
||||
|
|
|
||||
|
CHAPTER
I |
INTRODUCTION |
1 |
|||
|
1.1 |
Background |
1 |
|||
|
1.2 |
Statement of the Problem |
6 |
|||
|
1.3 |
Research Questions |
8 |
|||
|
1.4 |
Aim and Objectives of the Study |
9 |
|||
|
1.5 |
Significance of the Study |
9 |
|||
|
1.6 |
Spatial Limits of the Study |
10 |
|||
|
1.7 |
Definition
of Terms |
10 |
|||
|
|
|
|
|||
|
CHAPTER II |
LITERATURE REVIEW |
|
|||
|
2.1 |
Introduction |
13 |
|||
|
2.2 |
Theoretical
Background |
13 |
|||
|
2.3 |
Groundwater Discharge and Recharge |
20 |
|||
|
2.4 |
Water Regions Distribution In Libya |
22 |
|||
|
2.5 |
Groundwater
Situation in Libya |
26 |
|||
|
|
2.5.1 |
Groundwater
in Al- Jabal Al- Akhdar (North-East
Libya) |
27 |
||
|
|
2.5.2 |
Evolution
of the groundwater situation in Al- Jabal
Al- Akhdar and Benghazi plain |
28 |
||
|
2.6 |
Groundwater Pollution |
31 |
|||
|
2.7 |
Groundwater
for Water Supply |
36 |
|||
|
2.8 |
Methods
Application in Groundwater Studies |
39 |
|||
|
2.9 |
Water
Quality Index |
45 |
|||
|
2.10 |
Conclusion |
48 |
|||
|
|
|
|
|||
|
CHAPTER III |
DESCRIPTION OF THE STUDY AREA |
|
|||
|
3.1 |
Introduction |
49 |
|||
|
3.2 |
Historical Overview of the Region
of Derna |
49 |
|||
|
3.3 |
Location of the Study Area |
50 |
|||
|
3.4 |
The Climate of the Study Area |
50 |
|||
|
|
3.4.1 |
Temperature |
51 |
||
|
|
3.4.2 |
Rainfall |
52 |
||
|
|
3.4.3 |
Relative Humidity |
54 |
||
|
|
3.4.4 |
Air Depressions And Winds |
54 |
||
|
3.5 |
Topography |
56 |
|||
|
3.6 |
Soil |
57 |
|||
|
3.7 |
Geological |
57 |
|||
|
|
3.7.1 |
Tertiary |
59 |
||
|
|
3.7.2 |
Quaternary Sediments |
62 |
||
|
3.8 |
Water Resources in the Region |
62 |
|||
|
|
3.8.1 |
Water Sources |
61 |
||
|
|
3.8.2 |
Water Consumption |
65 |
||
|
3.9 |
Population Growth of the Study Area |
66 |
|||
|
3.10 |
Conclusion |
67 |
|||
|
|
|
|
|||
|
CHAPTER IV |
RESEARCH METHODOLOGY |
|
|||
|
4.1 |
Introduction |
68 |
|||
|
4.2 |
Data
Collection Stage |
68 |
|||
|
|
4.2.1 |
Literature Research |
68 |
||
|
|
4.2.2 |
Field Study |
70 |
||
|
4.3 |
Data
Analysis Stage |
76 |
|||
|
|
4.3.1 |
Laboratory
Analysis |
76 |
||
|
|
4.3.2 |
Statistical
Analysis |
76 |
||
|
|
4.3.3 |
Geographic
Information System (GIS) Analysis |
77 |
||
|
|
4.3.4 |
Water
Quality Index (WQI) |
79 |
||
|
|
|
|
|
||
|
CHAPTER V |
GROUNDWATER
POLLUTION SOURCES
AND ITS PROPERTIES |
|
|||
|
5.1 |
Introduction |
82 |
|||
|
5.2 |
Groundwater
Pollution Source |
83 |
|||
|
|
5.2.1 |
Natural
Sources |
84 |
||
|
|
5.2.2 |
Anthropogenic Sources |
84 |
||
|
5.3 |
Quality of Groundwater In the Study Area |
95 |
|||
|
|
5.3.1 |
Microbiological Properties of Groundwater |
96 |
||
|
|
5.3.2 |
Chemical
Properties of Groundwater |
99 |
||
|
5.4 |
Comparing
of Means of Groundwater Parameters
Concentrations Among the Region's Sections |
102 |
|||
|
5.6 |
Conclusion |
122 |
|||
|
|
|
|
|||
|
CHAPTER VI |
THE
SPATIAL ANALYSIS OF GROUNDWATER QUALITY |
|
|||
|
6.1 |
Introduction |
117 |
|||
|
6.2 |
The Spatial
Distribution of Groundwater Pollution |
117 |
|||
|
6.3 |
Water
Quality Index (WQI) |
130 |
|||
|
|
6.3.1 |
Water
Quality Parameters |
131 |
||
|
|
6.3.2 |
Water
Quality Index Estimation |
131 |
||
|
6.4 |
Multivariate
Linear Regression (MLR) |
135 |
|||
|
6.5 |
Conclusion |
140 |
|||
|
CHAPTER VII |
CONCLUSION |
|
|||
|
7.1 |
Introduction
|
142 |
|||
|
7.2 |
Conclusion of he Finding of the Study |
143 |
|||
|
|
7.2.1 |
Key Factors of Groundwater Pollution |
143 |
||
|
|
7.2.2 |
Quality of Groundwater in the Study Area |
147 |
||
|
|
7.2.3 |
Comparing of Means of Groundwater Parameters Concentrations Among the Region's
Sections |
149 |
||
|
|
7.2.4 |
The Spatial Distribution of Groundwater
Pollution |
150 |
||
|
|
7.2.5 |
Water Quality Index (WQI) |
152 |
||
|
7.3 |
Recommendations |
153 |
|||
|
|
|
|
|||
|
REFERENCES |
|
155 |
|||
|
|
|
|
|||
|
APPENDIXES |
|
167 |
|||
|
A |
A Questionnaire about Groundwater Quality of Agricultural
Area in the Region |
167 |
|||
|
B |
A Questionnaire About Groundwater Quality of Urban Area in the Region |
170 |
|||
|
C |
Climate Data |
173 |
|||
|
D |
Bacterial and Chemical Analysis of Water |
174 |
|||
|
E |
Statistical Analysis |
177 |
|||
ABSTRACT
In Libya, groundwater is the
main source of fresh water. The lack of water reduces the ability to maintain
quality, especially if there are multiple sources of pollution. The study aims
to provide information on the spatial characteristics of groundwater quality in
Derna Region, northeastern part of Libya. Specifically, the study focuses on
identifying the key factors that lead to groundwater contamination, its
suitability for human consumption and the spatial distribution of groundwater contamination.
Thirty-one water samples were collected and analyzed namely PH, EC, TDS, T.H,
Ca++, Mg++, Fe, NH4, C1, NO2, PO4 and E. coli. Chi square, one-way ANOVA and
regression analyses were employed to analyze the statistical data gathered from
the stratified relative sampling carried
out within the study area. The Geographical Information system (
ABSTRAK
Di
Libya, air bawah tanah merupakan sumber utama bekalan air. Kekurangan sumber
air akan mengurangkan keupayaan dalam stabilkan kualiti, terutama apabila
terdapat beberapa sumber pencemaran. Kajian ini bertujuan untuk memberikan maklumat mengenai ruang ciri kualiti
air bawah tanah di Wilayah Derna, bahagian timur laut Libya. Secara khususnya,
kajian ini memberi tumpuan untuk mengenal pasti faktor-faktor utama yang
membawa kepada pencemaran air bawah tanah, membincangkan kesesuaiannya untuk
kegunaan manusia dan taburan pencemaran air bawah tanah. Borang soal selidik
telah dibuat, dan 31 sampel air telah dikumpulkan dan parameter yang adalah
seperti PH, EC, TDS, TH, Ca + +, Mg + +, Fe, NH4, C1, NO2, PO4 dan E.coli. Chi square, ANOVA sehala dan analisis regresi telah digunakan untuk
menganalisis data statistik yang dikumpulkan dari pensampelan berstrata relatif
yang dijalankan di dalam kawasan kajian. Teknik Sistem Maklumat Geografi GIS
telah digunakan sebagai model untuk menghasilkan peta taburan kualiti air bawah
tanah.Status pencemaran dikira dan dibandingkan dengan Indeks Kualiti Air (WQI)
seperti yang diiktiraf oleh Pihak Berkuasa Air Besar di Libya. Hasil kajian
menunjukkan bahawa limpahan kumbahan, pengumpulan sisa racun perosak dan baja
sumber-sumber pencemaran air bawah tanah berdasarkan hasil analisis soal
selidik ini, di mana 67 % (n = 450) daripada jumlah penduduk mengesahkan bahawa
terdapat limpahan kumbahan, dan 65 % (n = 450) daripada mereka mendapati sisa
terkumpul. Sebaliknya, kajian telah menunjukkan bahawa lebih daripada dua pertiga
(2 / 3) petani telah menggunakan racun serangga dan baja. Chi square telah menunjukkan kaitan dua faktor di atas dengan perubahan
kualiti air. ANOVA sehala menunjukkan bahawa terdapat perbezaan dalam purata
jumlah E.coli antara bahagian-bahagian di rantau ini. Di Al-Belad yang
mempunyai purata tertinggi jumlah E.coli
(50/100 cm3) disebabkan oleh kepadatan penduduk tertinggi dengan yang dipakai
sistem pembetung. Analisis ANOVA
menunjukkan (nilai P = 0.814). TDS, TH, Cl dan E.coli telah melebihi jumlah yang dibenarkan dalam beberapa sampel
iaitu 8000 mg / l, 1700 mg / l, 1140 mg / l dan 100 kuman bagi setiap 100 cm3,
masing-masing. Peta penzonan GIS parameter kualiti air menunjukkan kepada
sebahagian besar daripada nilai-nilai parameter yang tinggi tertumpu di
bahagian utara dan barat laut rantau ini, di mana peningkatan kepadatan
penduduk dan pembandaran. Nilai WQI air bawah tanah antara 20,63-100, dan
mendedahkan bahawa 14.3% adalah air bersih (kelas Ia), 64.3% adalah air
sederhana tercemar(kelas Ib) dan 21.4%
air yang sangat tercemar(kelas IIIa&b), sebagai merujuk kepada indeks
kualiti air di Libya. Daripada keputusan Multivarian Regresi Linear (MLR)
penentuan (R2) adalah 0.914 yang bermaksud bahawa 91% daripada
variasi dalam pembolehubah bersandar (WQI) yang dijelaskan oleh set ramalan
(parameter WQ). MLR menunjukkan bahawa WQI didapati songsang yang berkait rapat
dengan kebanyakan parameter kualiti air (77.8% daripada mereka) yang
menunjukkan untuk meningkatkan kualiti air apabila kepekatan parameter air
menurun.
CHAPTER VII
CONCLUSION 7.1
INTRODUCTION
Provision of clean water to a population remains a major global
challenge, particularly in urban areas, where a large number of people and
different activities take place in a relatively smaller area, and it is one of
the measures of welfare. Furthermore, lack of rainfall and sources of surface
water exacerbate the problem especially in the arid and semi-arid regions.
This study addressed the issue of contamination of groundwater in the
region of Derna in the northeastern part of Libya. The study focused on the key
factors that cause the groundwater pollution by studying sample of the
residents regarding their perceptions of the environmental situation in the
region and the quality of ground water. This study also analyzed the chemical
and microbiological characteristic of the water. Also , the geographic
information systems (GIS) was used to determine the spatial distribution of
groundwater quality. The study had successfully demonstrated that the
application of GIS technique is a powerful tool in evaluating and describing
the spatial analysis, and mapping of the groundwater characteristics. The study
also discussed and determined the suitability of the groundwater for human consumption
based on the computed Water Quality Index (WQI).
The study, which was aimed to
provide information on the chemical and microbiological characteristics of
groundwater quality in the region, spatial distribution of groundwater quality
and its suitability for human consumption.
To reach these goals varieties of data were collected from
questionnaires and groundwater samples. Where, two comprehensive questionnaires
- counting on several important questions have a relationship with the subject
of the study - were designed and distributed to 450 (427 in Derna city and 23
in Al-Ftaih region) respondents as a sample of the study. Thirty one
groundwater sources samples were collected (wells and springs) and analyzed
for; PH, Electric Conductivity (EC), Total Dissolved Salts(TDS), as well as
Total Hardness(TH), Calcium (Ca++), Magnesium(Mg++), Iron(Fe), Ammonia(NH4),
Chlorides(C1), Nitrite(NO2), Phosphate(PO4), in additional to the Bacterial
analysis (E. coli).
The groundwater samples were analyzed in the Central Laboratory in the
General Water Authority, Derna to analyze the above parameters. The statistic
package of social science (SPSS) program was used to analyze the data to find
some of statistical relationships. The descriptive statistic and Chi square
were used to identify the relationship between the groundwater pollution
sources and the changes in the groundwater quality. The one - way analysis of
variance (ANOVA) was applied to compare means and the differences of
groundwater parameter concentrations among the region's sections, and Post Hoc
test was also used to unveil the differences between the means. Multivariate
Linear Regression (MLR) was employed to investigate the relationship between
each of the independent variables (water quality parameters) and the dependent
variable (Water Quality Index). Arc View software in Geographic Information
Systems (GIS) was employed as a tool for analysis and to produce maps of the
spatial distribution of concentrations of groundwater quality parameters. Also
Water Quality Index (WQI) was employed to determine the water quality status
and its suitability for domestic consumption.
7.2 CONCLUSION OF THE FINDINGS OF
THE STUDY
7.2.1 Key Factors of Groundwater Pollution
The summary of the study discussed the key
factors or the main sources of pollution of groundwater in the region of study.
Which were natural and anthropogenic. The 144 survey conducted for analyzing
the quality of groundwater and environmental conditions had identified the
following factors: a) Natural Factors
In the study area there are some natural impurity concentrations in the
ground water, which depend on the nature and type of the soil, sediment and
rock through which the groundwater moves, and the quality of the recharge
water, as well as the distance of the region to the seawater. Excessive
withdrawal of water from underground reservoirs near the coastal strip,
especially those which are shallow have led to the influx of saltwater from the
sea to compensate the losses in fresh groundwater, and thus the salinity of the
water has exceeded standards of drinking water.
Hence, an increase in salinity rates in some of groundwater wells have
been identified, especially those which are close to the coastline. About 35.1%
of residents perceived that there is a significant increase in the groundwater
salinity rate, 54% of them have thought that seawater intrusion as the main
reason for the increase in salinity, while the remaining thought that declining
groundwater level and the nature of geological formations as the key factors.
b) Anthropogenic Factors
The anthropogenic sources of pollution are the result of human
activities, such as municipal, agricultural or industrial. These activities
generate waste in the form of liquid, solid or gaseous, and include the
followings:
I. Sewage Systems
Sewage systems are considered as the biggest source by the volume of
waste and pollutants discharged to the land. The wastewater leakage in the
region is either from septic tanks or through sewage network pipes and is considered
as a pollution source of groundwater. Accordingly, there are two means of
wastewater disposal in the region:
a. Black Reservoirs (Septic Tanks)
In the study area, most septic tanks are very poorly located,
constructed and designed, and are covered only from the top. This led to the
leakage of the sewage directly into ground water. Based on the survey, it was
found that about 72.2% of residents rely on septic reservoirs to dispose of
their wastewater, and approximately 40.5% of them did not discharge their
reservoirs.
b. Sewage Networks
The sewage networks system in Derna region was established in the
sixties of last century, and no longer able to accommodate the current
population density of the region and become dilapidated and spills out the sewage.
67% of the population surveyed indicated that, there is an overflow of sewage
from networks. This resulted in big ponds being formed of containing pollutants
on the ground, which caused soil pollution and eventually leaked into the
aquifer. At the same time, all sewage lift stations have been out of order and
are neglected and exposed to burglary and finally have become garbage landfill.
The sewage treatment plant, which was constructed in 1980, was not fully
completed hence it has been left to neglect and vandalized and is now at a
dilapidated stage with little actual value. All these led to leakage of sewage
into aquifers.
The statistical analysis revealed that there was a significant
association between the groundwater quality change and the overflowing of
sewage. 75.7% of respondents have indicated that there is a significant change
in the quality of groundwater in the areas that have an overflow of wastewater.
The analysis yielded a chi-square value of 27.407, which was significant at the
0.05 level (P value = 0.000). Therefore, this can be concluded that there is a
significant association between the groundwater quality change and the
overflowing of wastewater.
II. Solid Waste and Disposal System
In the city, on the average, 70 tons or about 25,550 tons per year of
solid waste are produced, which contain different kinds materials mostly
organic in nature (Environmental Protection Agency 2004). The region depends on
the traditional means of solid garbage disposal; the wastes are thrown in open
dumps and then burnt without any processing. Furthermore, what makes matters
worse is that, these dumps is not far from the residential areas, however, some
dumps are on the edge of the city’s border, especially in the east of the city,
where the main landfill is found. Besides that, wastes are thrown on the
streets, which accumulate and stack as garbage. About 65% of respondents have
noticed on this problem, this happens because of the underperformance of the
sanitary cleaning authority of the city and insufficient number of equipments
and machineries available for the task and the lack of follow-up to the daily
work of cleaning the city. These pollutants can leak with rainwater to
groundwater especially when most of geological formations are limestones which allow
leaks of contaminants to the aquifers.
Analysis of data showed that there was a significant association between
the groundwater quality change and the accumulated solid waste in most empty
places, where more than two thirds of the respondents have noticed that.
Therefore, the analysis yielded a Chi-square value of 1.096 at P value = 0.295.
III. The Excessive Use of Pesticides
and Fertilizers in the Farmland
The quantity of water used for agricultural purposes are estimated to be
25.6% of the total water use in the region, and this leads to decline the
groundwater level and thus increase of salinity rate.
Pesticides have been widely used in the farms. The study has shown that
74% of farmers used pesticides to eliminate insects and weeds and to protect their
cultivation, which in turn leak and pollute the groundwater directly or
indirectly. On the other hand, 56.5% of farmers have noticed that there is a
significant change in the quality of groundwater in the agricultural areas, and
most of them have used pesticides in their farms. The analysis had revealed
that the Chi-square value was 4.960, which was significant at the 0.05 level (P
value = 0.026). However, it can be concluded that there is a significant
association between the groundwater quality change and use of pesticides.
Some of chemical compounds originating from fertilizers were reported to
be the primary source of groundwater contamination. Most of the farmers in the
region use many types of fertilizers, in order to improve the soil fertility
and thus increase production. There were about 65% of them who use fertilizers,
which affected the groundwater quality, and 80% of them had noticed that there
is a significant change in the quality of groundwater. The statistical analysis
had yielded that there is a significant association between the groundwater
quality change and the use of pesticides, where the Chi-square value was 6.626
which was significant at the 0.05 level (P value = 0.010).
7.2.2 Quality of Groundwater in the
Study Area
a) Microbiological Properties of
Ground water
In the study area, the largest concern for groundwater is bacterial
pollution. This may be due to the poor performance and lack of interest in the
sewage management, where most of the sewage networks are on run-down state as
well as relying on septic tanks in the disposal of sewage, especially in
selected areas and developing neighbourhoods.
Most of water samples collected are not suitable as drinking water,
because there was evidence of bacterial growth based on the Libyan standard
specifications for drinking water, and at the same time it has an effect on
human health. Accordingly, the source of pollution should be removed by
chlorination of water according to the prescribed ratios for water treatment.
In general, there was an increase in the coliform bacteria ratios, the highest
recorded coliform bacteria count was 100 in each 100 cm3, and thus it is not
suitable for drinking and other human uses.
b) Chemical Properties of
Groundwater
The chemical analysis showed results as the following:
a. The groundwater in the study area
was neutral to slightly alkaline as its pH varies from 6.8 to 8.1.
b. The maximum value of EC was 12050
μ
S/cm, and the minimum was 780 μ S/cm at the Spring of Abu-Mansour,
with a mean of 2630.417 μ S/cm, this was due to the increase
of salts.
c. The TDS values in some wells
exceeded the permissible maximum limits with an average of 1889.923 mg/l and
the maximum was 8000 mg/L. The high amount of TDS in groundwater may be due to
seawater intrusion and low water level resulting from increased withdrawal and
lack of rain particularly in the summer season.
d. Five wells high concentrations of
TH and exceeded the allowable maximum limit, where the highest value was 1700
mg/L.
e. The Ca++ concentrations in the
water samples are within allowed limits except one, which was 280 mg/L.
f. Fe, NH4 and NO2 concentrations
were found to be more than permissible limits for drinking water in some
samples.
g. One sample had very high
concentration of C1 which was 1140 mg/L, and the C1 permissible limit was
exceeded in about 28% of samples. PO4 was existent in three wells.
h. The springs are almost devoid of
high concentrations of chemicals that exceed the standard limit of drinking
water.
7.2.3 Comparing the Means of the
Concentrations of Groundwater Parameters Among the Sections in the Study Region
One-way analysis of variance (ANOVA) was used to determine the
differences in the concentrations of groundwater parameters within the region.
The analysis found that there were significant variations between the parameter
concentrations within the region’s sections, as follows:
· The average of E. coli count in
the region was 16.8065 in each 100 cm3, but the average for the eight sections
seemed to be different and most of them were more than the permissible limit of
the Libyan standards. The highest average was 50 counts in Al-Belad and the
lowest was 6.7 in Al-Sahil, and the ANOVA analysis showed P.value of 0.814.
· The mean of TDS concentrations in
the region was 1976.3571mg/L. The highest average of TDS concentration was 4320
mg/l in wells of Abu-Msafir, while the lowest was 605 mg/L in the springs. The
one-way ANOVA showed a significant result with F-ratio of 0.657, which was not
significant at the 0.10 level (P.value = 0 .687).
· The average of TH concentration in
the region was 536.4386 mg/L, but the averages for the all sections of the
region look somewhat different. The TH concentration in groundwater in three
sections was found to be higher than the permissible limit of the Libyan
standards. The highest average of TH concentration was 1010 mg/L and found in
Abu-Msafir, whereas the lowest concentration was 295 mg/L in the springs area.
The analysis of one-way ANOVA showed a significant result with F-ratio of 0.669
which was not significant at the 0.10 level (P.value = 0.680).
· The EC concentrations in the
region was 2586.79 μS/cm, however, the averages for the
all sections of the region did not seem to be of close approximates, where
there were minor differences. The highest average of EC concentration was 7962 μS/cm
in Al-Belad & Al-Jubaila in the central part of Derna city. Whereas the 150
lowest concentration was 219 μS/cm in the springs area. The
one-way ANOVA analysis revealed that F-ratio = 0.669 which was not significant
at the 0.10 level (P.value = 0.680).
· The mean of Ca concentration in
the region was 112 mg/L. The highest average of Ca concentration was 172 mg/L
in Abu-Msafir in the north-western part of the region. Whereas the lowest
concentration was 56 mg/l in Al-Sahil in the northeastern part of the region.
The analysis of one- way ANOVA showed that the Fratio = 0.657 at (P.value = 0
.687), it is more than the level of significance (0.10).
· The mean of Mg++ concentration in
all parts of the study area was 68.92 mg/L and it was lower than the
permissible limit. Most of the averages seemed to be of close approximates
except two sections; the Abu-Msafir area in the north-western part of the
region recorded the highest value of 153.5 mg/L, and the lowest concentration
was 21 mg/L in Al-Ftaih area in the southeastern part of the region. The
analysis of one- way ANOVA showed that the F-ratio = 1.064 at (P.value =.462).
· The mean of Cl concentrations in
all parts of the region was 266.67mg/L and it was slightly higher than the
permissible limit. However, the averages for the all sections of the region
seemed not to be of close approximates. The highest concentration of Cl in the
region was 650 mg/L in the Abu - Msafir area, and the lowest concentration was
120 mg/L in the north-eastern part of the region. The analysis of one-way ANOVA
showed that the F-ratio = .817 at (P.value =.579).
7. 2. 4 The Spatial Distribution of
Groundwater Pollution
According to the GIS zonation maps, spatial distributions of groundwater
parameters were as the following:
· The spatial distribution of total
hardness (TH) varied from 320 to 1700 mg/L. The highest values of TH were
concentrated in the north-western part of the study area, which exceeded the
allowable maximum limit.
· The pH values ranged from 6.8 to
8.1. The GIS map of spatial distribution showed that the highest value of pH
was 8.1 and observed in the southern part of the region in the Spring of
Abu-Mansour.
· Most of TDS concentration in the
groundwater samples in the region ranged between 640 mg/L and 1300 mg/L, and
was higher than the permissible limit in 35.5% of samples. The highest
concentration of TDS was observed in the northwestern part with 8000 mg/L and
some other sporadic parts of north and east of the region.
· The highest value of EC was
concentrated in the north-western part of the region and the lowest in the
south and east. The EC values had ranged between of 790 to over 12000 μ
S/cm.
· The Ca++ map indicated the
presence of the highest value also in the north-western part of the region with
a range of 124 – 280 mg/L. The next higher range of Ca++ with 93 - 187 mg/L,
and was found in the central part of the city.
· Mg++ values in the region varied
from 10 to 243 mg/L. Only 7% of samples showed Mg++ above the permissible
limit, and were concentrated in the northwestern section of the region.
· There was a slightly high
concentration of the Iron observed in the central and eastern part of the
region. The Fe values ranged between 0 – 0.2 mg/L. · There was a slightly high
concentration of NH4 found in the west of the central part of the study area.
The values of NH4 varied from 0 to 0.2 mg/L.
· The Cl values ranged between 80 to 1140
mg/L, and about 28% of the study samples were higher than the permissible
limit. The maximum of C1 value was observed in the western part of the region,
as well as at other high point in the center of Derna city and the village of
Al-Ftaih.
· The spatial distribution map of
NO2 showed that the NO2 values ranged between 0 to 0.2 mg/L. The highest
concentration was observed in the western part of Derna city, it decreased
gradually to the southward and eastward direction.
· PO4 concentrations map had shown
that its values ranged between 0 to 1 mg/L. The maximum was concentrated in the
west of the central and eastern parts of the Derna city (locality of Al-Maghar
and Al-Sahil), whereas the lowest concentrations were observed in the southern
part of the region.
· The spatial distribution of E. coli count
varies from 0 – 100 in each 100 cm3. The highest number of E. coli in the
groundwater were concentrated in the central and western part of the Derna
city, while the E. coli count was less than 33 in 100 cm3 southern and eastern
parts of the region.
7.2.5 Water Quality Index (WQI)
Pollution status was estimated using Water Quality Index (WQI) range and
water quality classes were evaluated using values of nine water quality
parameter for WQI. The nine parameters are pH, TDS, TH, Ca++, Mg++, Fe, Cl, PO4
and E. coli. The WQI values are very much dependent upon the value of PO4 in
water. The WQI values had revealed that, the groundwater quality in the region
was absolutely clean in only 14.3% of the groundwater samples; with WQI values
of 100. The slightly polluted in quality was found in about 64.3% of samples;
with WQI ranged between 88.50 and 99.81. Lastly, the groundwater quality in
21.4% of the samples were very poor and cannot be used for domestic purposes
especially for drinking.
The spatial distribution of the
overall groundwater quality in the region showed that the severely and
excessively polluted water are concentrated in two parts, central and western
parts of the Derna city, with slightly contaminated water in the middle part.
The quality of water begins to increase from south and east direction.
The statistical analysis found that, some of the independent variables
were medium to high positive correlated to each other. The dependent variable
(WQI) had an inverse correlation with some of independent variables such Fe,
PO4 and E. coli, implying the WQI decreases when Fe, PO4 and E. coli increase.
The derived MLR of determination (R2) is 0.914, which means that 91% of
variations in the dependent variable are explained by the set of predictors.
The analysis produced a significant regression model with F value of 4.697 at
the 0.10 level. The model can be written in following form:
WQI = 108.351-1.855 pH- .007 TDS -
.047 TH + .286 Ca - .186 Mg -152.587 Fe+ .075 Cl - 56.464PO4 - .145E.coli
The B
values were shown to inversely correlate with 77.8% of the water quality
parameters, and PO4 had the greatest influence on WQI. At the individual level
PO4 was the most significant variable in explaining variation in the WQI
followed by Fe. Clean water quality was associated with low concentrations of
pH, TDS, TH, Ma++, Fe, PO4 and E. coli. This indicates that increase in water
quality occurs when the concentrations of these water parameters were low.
7.3 RECOMMENDATIONS
Based on the findings discussed the recommendations of this study are as
follows:
Avoid using shallow water wells especially near coastal areas, and cut
down on the sinking wells in the region and try to find other sources of water
for the region, in order to maintain the groundwater level and as well as its
quality.
Laws are needed so that solid waste are not disposed of indiscriminately
near sources of water and special sites should be created for the disposal of
waste in a safe manner in order to maintain the environment as well as the
health of human.
Empty the septic tanks and reduce sewage
overflow by means of the establishment and maintenance of drainage networks in
all sections of the region. And also build of sewage treatment plants.
Reduce the use of pesticides and chemical fertilizers in the farmland
and use biological fertilizers instead in order to mitigate the leakage of
chemical pollutants to the aquifers.
Encourage the recycling of solid
wastes, and the awareness of the population regarding sorting of wastes so as
to reduce the quantity and the accumulation of these wastes. Also provide the
necessary modern equipments to water analysis laboratories as well as for the
preparation of specialized techniques to periodically monitor the water quality
sources.
download
👇
👇
👇
👇
👇
DOWNLOAD OPTIONS
\
ليست هناك تعليقات:
إرسال تعليق