Baseline Analysis of Ground Water Quality Around Open Dumpsites in Lagos, Nigeria: Focus on Polynuclear Aromatic Hydrocarbons Open Access

Dayo, Mayowa (2013)

Permanent URL: https://etd.library.emory.edu/concern/etds/x633f1286?locale=en
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Abstract

Background: Providing a sustainable means of waste disposal is one of the major problems in Lagos. For many years, the State government has used open dumpsites to dispose of the waste generated in the city. The physical, chemical and biological processes that occur simultaneously at open dumpsites can result in generation of leachate and other waste gases. The leachate and waste gases formed are the source of pollutants that can lead to environmental and health problems (Rushbrook, 2001). Therefore, communities that tap into polluted groundwater may be exposed to various levels of harmful chemical contaminants that can lead to chronic diseases such as cancer.

Objective: To evaluate groundwater contamination around open dumpsites, the presence of polynuclear aromatic hydrocarbon pollution in the study area was ascertained by sampling water from boreholes and wells in houses around open dumpsites.

Method : Water samples were collected from households around two open dumpsites in Lagos Nigeria. Samples were collected over a two-day period in 2012 and analyzed at a Lagos State Environmental Protection Agency Laboratory in Lagos. Coordinate points for each sample site were collected on field and used to evaluate the dispersion of total PAHs. Non-parametric methods were used for statistical data analysis and Monte Carlo Simulation (MCS) based analysis was used to impute non-detected values.

Result: Seven of the sixteen PAH compounds tested for were present in at least four sites of the fourteen sampling sites. Before MCS, four of the seven compounds were significantly higher than the maximum contamination level (MCL). After MCS all sites had PAHs level higher than MCL and maximum contaminant level goal (MCLG). Also, there was no difference in PAHs level between sites.

Discussion: A combination of the laboratory, statistical and geographic information analysis provided evidence of groundwater contamination at both study sites. The Lagos state government needs to improve on the waste management system to avoid contamination of groundwater aquifer that may pose future health risk.

Table of Contents

Table of Contents

Chapter 1: Introduction................. 1

1.1. Background........ 1

1.2. Significance........ 5

1.3. Objective........ 5

Chapter 2: Literature Review................. 6

2.1. Introduction........ 6

2.2. Waste Management in Lagos........ 6

2.3. Water sources in Lagos........ 9

2.4. Geology and Hydrogeology of the study area........ 11

2.5. Polynuclear aromatic hydrocarbons........ 12

2.6. Physical properties of PAHs that determine flow in groundwater........ 15

2.7. GIS and Public Health........ 16

2.8. Gaps in literature........ 17

Chapter 3: Methodology................. 19

3.1. Hypotheses........ 19

3.2. Study Design........ 19

3.3. Ethics........ 20

3.4. Field sampling........ 20

3.5. Laboratory Tools........ 21

3.6. Reagents........ 21

3.7. Extraction procedure........ 21

3.7. Concentration and Drying........ 22

3.8. Instrument........ 22

3.9. Experiment........ 23

3.10. Method validation........ 24

3.11. Statistical Analysis........ 24

Chapter 4: Results................. 26

4.1. Preliminary Analysis........ 26

Table 1: Total PAHs concentration by sampling site (mg/L).... 26

Table 2: PAHs concentration in groundwater samples in (mg/L), prior to MCS.... 27

4.2. Monte Carlo Simulation Analysis........ 27

Table 3: PAHs concentration in groundwater samples (mg/L), after MCS.... 28

Table 4: PAHs concentrations in groundwater samples by site (mg/L).... 28

Table 5: PAHs concentration in groundwater samples Control vs. Both Dumpsites (mg/L).... 29

Table 6: Total Uncertainty Interval for MCS (mg/L).... 29

Table 7: Non-detected PAHs concentration imputed by MCS (mg/L).... 29

Chapter 5: Summary................. 30

5.1. Discussion........ 30

5.1.1. PAHs Concentration.... 30

5.1.2. Physical Environment and PAHs.... 34

5.1.3. Limitations.... 35

5.2. Conclusion and Recommendations........ 36

5.3. Maps & Graphs........ 38

NE areas have higher PAHs concentrations..... 40

References................. 43

Appendix................. 47

Table1: Characterization of groundwater samples.... 47

Table 2: PAH analysis using GC-FID instrument.... 47

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