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Leachate Characterization, Pollution Load Assessment, and Waste

Management Infrastructure Policy for an Unregulated Open

Dumpsite in a Tropical Peri-Urban Environment: Evidence from

Benin City, Nigeria

Osayande, A. D*

; Okojie, M.E

and Offiah, E.N³

1,3

Department of Geology and Mining Technology, University of Port Harcourt, P.M.B 5323

Choba, Port Harcourt Nigeria

Department of Geology, Faculty of Physical Sciences, University of Benin, P.M.B 1154, Benin

City, Nigeria.

DOI:

https://doi.org/10.51583/IJLTEMAS.2026.150500249

Received: 27 May 2026; Accepted: 01 June 2026; Published: 23 June 2026

ABSTRACT

The leachate resulting from improperly managed and unregulated open dumpsites acts as a proximate and

immediate link between waste accumulation and resultant groundwater and soil contamination; however, it has

received relatively little attention in terms of analytical studies within the Nigerian environmental literature

compared to the resultant endpoints of contamination. This study seeks to provide a comprehensive

characterization and pollution load assessment of the leachate from the Upper Ekehuan/Asoro open dumpsite in

Ovia North-East LGA, Edo State, Nigeria, with a focus on two leachate samples obtained from active zones of

seepage within the site, employing the Pollution Load Index and Nemerow Pollution Index models. The results

showed that the leachate was of extreme pollution potential with Iron concentrations of 66.65–103.85 mg/L or

67–104 times over the WHO limits; Nickel concentrations of 4.73–7.37 mg/L or 237–369 times over the WHO

limits; Cadmium concentrations of 0.87–0.93 mg/L or 174–186 times over the WHO limits; and Hexavalent

Chromium concentrations of 1.98–3.08 mg/L or 40–62 times over the WHO limits. The PLI value ranged from

62.4 to 94.7, indicating that both leachate samples fall within the 'Extremely Polluted' category. Comparatively,

this study found that the leachate from this site compares favorably with the most polluted leachate from landfill

sites across Africa. A conceptual model of a Source-Pathway-Receptor relationship was employed to illustrate

the pathway of contamination resulting from the leachate. This study concludes that no investment in soil and

groundwater remediation will be effective if the pathway of leachate contamination and infiltration is not first

addressed and halted. This study also offers policy recommendations to NESREA, the Federal Ministry of

Environment, and the SWMA of Edo State.

Keywords: leachate characterization, pollution load index, Nemerow pollution index, source-pathway-receptor

model, waste management hierarchy, dumpsite remediation, open dumpsite, Nigeria

INTRODUCTION

The World Waste Management Problem is, at Its Most Fundamental Level, a Leachate Problem. Every Ton of

Waste with Organic Matter Entering a Land-Based Waste Disposal Site Creates Leachate – the Complex, Highly

Polluted Liquid Created as Precipitation, Surface Water Runoff, and Moisture Leach through the Waste

Materials (Kjeldsen et al., 2002; Renou et al., 2022). The Composition of Leachate is the Complete Set of Waste

Chemicals – Organic Acids, Ammonia Nitrogen, Dissolved Heavy Metals, Chlorinated Solvents,

Pharmaceuticals, and Pathogenic Microbes – which Combine to Create a “Chemical Cocktail” so Highly

Polluting that when Leachate Reaches the Groundwater Table, the Groundwater is Made Unusable for Decades

to Centuries (Naveen et al., 2022; Youcai, 2021).

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In the African Context, the Leachate Problem is Particularly Acute. Waste Segregation is Minimal, so Organic

Waste is Mixed with Electronic Waste, Medical Waste, Industrial Chemicals, etc., to Create Leachate with a

Chemical Complexity Unlike Anything Seen Outside the African Continent (Asante-Duah, 2022; Kaza et al.,

2021). The Prevalence of Open Dumpsites with No Liner, No Leachate System, and No Cover Means Leachate

Immediately Leaches into the Soil and Groundwater (Wilson et al., 2021). The Tropical Climate Conditions

Accelerate the Rates of Waste Decomposition and Leachate Generation (Renou et al., 2022).

Yet Leachate Characterization Research from Nigeria is Wanting, with the Majority of Existing Research Simply

Assuming the Existence of Leachate without Exploring the Issue Further (Longe & Balogun, 2021; Nwachukwu

et al., 2021). The Problem This Study Seeks to Address is: What is the Classification of Pollution Load and the

Intensity of Contamination of Leachate at Upper Ekehuan, How it Relates to the Source-Pathway-Receptor

Model of Groundwater Contamination, and What Waste Management Infrastructure and Policy Interventions

are Necessary to Break the Chain of Contamination?

THEORETICAL FRAMEWORK

The primary theoretical framework is the Waste Management Hierarchy (WMH) as stipulated in the European

Union Waste Framework Directive (2008/98/EC) and adopted as a guiding principle in the UNEP Global Waste

Management Outlook (Wilson et al., 2021). The hierarchy ranks waste management strategies in descending

order of environmental preference as follows: Prevention > Reuse > Recycling > Recovery > Disposal. Open

dumping is the least preferred option. The WMH is underpinned by the priority principle of source control,

which dictates that interventions to prevent contaminant generation are always preferable to interventions to treat

contaminants after their release. Remediation of soil or groundwater pollution will be only temporarily and

partially successful as long as the leachate source continues to generate and infiltrate without hindrance. The

Source-Pathway-Receptor (SPR) model is the complementary theoretical framework to the WMH (DEFRA,

2012; Nathanail & Bardos, 2021). The SPR model conceptualizes the process of environmental contamination

as requiring the presence of three elements: a Source (the dumpsite leachate), a Pathway (the infiltration through

the vadose zone and the aquifer), and a Receptor (the human consumer of the borehole water). Interruption of

any of the elements will prevent the harm.

Study Area

The Upper Ekehuan (Asoro) dumpsite is located at 6°19'20"-6°19'40"N Latitude and 5°35'0"-5°35'20"E

Longitude in Ovia North-East LGA of Benin City, Edo State Nigeria. The dumpsite is situated in a basin-shaped

depression with a gentle slope to the terrain such that surface runoff from the adjacent roads and residential areas

is channeled into the waste deposit site. Two leachate seepage zones were identified: L1 at the central depression

and L2 approximately 20 meters to the north of L1. The dumpsite accepts mixed municipal solid waste with no

provision for source segregation. The average annual temperature is 27-32°C with 1,800-2,200 mm average

annual rainfall, providing a highly active decomposition environment with high leachate production rates year-

round.

Groundw

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Figure 2 Map of Ovia North East

MATERIALS AND METHODS

Leachate Sample Collection

Two leachate samples were collected from active seepage accumulation zones with wide-mouthed pre-cleaned

HDPE containers. The leachate samples were collected in duplicates and preserved according to parameter-

specific protocols (APHA, 1993): immediately acidified to pH < 2 with trace metal-grade HNO₃ for heavy metal

analysis; and chilled to 4°C for COD and nutrient analysis.

Analytical Methods

Physicochemical parameters were analyzed according to standard protocols: pH and EC with a digital pH/EC

meter; Turbidity with a HACH DR 2010 spectrophotometer; Total Dissolved Solids with a gravimetric method

according to Ademoroti (1996); Total Hardness and Alkalinity with a titrimetric method; Sulphate with a

turbidimetric method; Nitrate and Chloride with a colorimetric method according to APHA (1993); Phosphate

with an ascorbic acid reduction method according to ASTM (1990); COD with a dichromate reflux method; and

Heavy Metals with an AAS method according to BUCK SCIENTIFIC Model 210 VGP, USA.

Pollution Load Index

PLI = (CF₁ × CF₂ × CF₃ × ... × CFₙ)^(1/n), where CFᵢ = Cᵢ/Cᵢ_background (Angulo, 1996; Zhang et al., 2021).

The WHO drinking water guideline value served as the background reference for each parameter. PLI = 1

indicates pollution at background level; PLI > 10 indicates extreme pollution.

Nemerow Pollution Index

NPI = √[(Pavg² + Pmax²) / 2], where Pavg = average of all individual pollution index values (Pᵢ = Cᵢ/Sᵢ) and

Pmax = maximum individual Pᵢ. The NPI explicitly penalizes extreme individual parameter exceedances.

Classification: ≤ 0.7 (clean); 0.7–1.0 (slightly polluted); 1.0–2.0 (lightly polluted); 2.0–3.0 (moderately

polluted); > 3.0 (heavily polluted).

Source-Pathway-Receptor Ratio Analysis

L:GW ratio = C_leachate (mean of L1, L2) / C_groundwater (mean of GW1–GW3, proximal wells at 100–160

m). This ratio is a proxy for the dilution and attenuation factor between the leachate source and the near-field

receptor.

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RESULTS

Leachate Physicochemical Profile

The leachate pH of L1 (5.36) and L2 (5.24) is indicative of a strongly acidic environment, typical of acidogenic

degradation processes. This low pH level significantly increases the solubility of Cd, Ni, Pb, Cr, and Zn, thus

heightening the leaching potential of these metals (Kjeldsen et al., 2002). Similarly, the EC of L1 (210

microSi/cm) and L2 (176 microSi/cm) is also elevated. While the TDS of L1 (33.5 mg/L) and L2 (21.5 mg/L) is

also high, the leachate pollution hazard is largely from the inorganic toxic metals. Iron levels have the most

dramatic exceedance. L1 iron levels (103.85 mg/L) are 104 times the WHO guideline value of 1.0 mg/L.

Moreover, the iron level in L1 is 346 times the NSDWQ standard. L2 iron (66.65 mg/L) is a 67-fold exceedance

of the WHO standard. This extreme level of iron is typical of a leachate from a dumpsite where the waste includes

a substantial amount of structural iron from construction waste, scrap metal, and tin cans (Renou et al., 2022).

COD levels of L1 (58.29 mg/L) and L2 (37.41 mg/L) are relatively low. This would suggest that the dumpsite

is now in the methanogenic-transitional stage of decomposition, where the waste matter is largely decomposed

except for the inorganic waste matter (Youcai, 2021), implying that the dumpsite would continue producing

leachate for decades to come, even if there were no further waste being dumped.

Pollution Load Index and Nemerow Pollution Index

The calculated PLI values for the leachate samples were 94.7 for L1 and 62.4 for L2. These values were

extremely high compared to the ' polluted' limit of 10.0. The main contributing pollutants were Iron, which has

a CF = 346; Nickel, which has a CF = 369; Cadmium, which has a CF = 186; and Chromium(VI), which has a

CF = 62. The calculated NPI values were 226.4 for L1 and 148.9 for L2. This places the leachate firmly in the

“polluted' category, as the NPI is well above the 3.0 limit. Even if 18 out of the 20 parameters were within

acceptable limits, the very high Iron and Nickel concentrations make this leachate a high-priority environmental

hazard.

Comparative Analysis with African and International Leachate Benchmarks

Compared to Lagos Olusosun landfill leachate (Longe & Balogun, 2021), Upper Ekehuan shows lower COD

(58 vs. 1,200–8,500 mg/L) but higher Nickel (5.8–7.4 mg/L vs. 0.8–2.1 mg/L), suggesting a site-specific

geochemical influence from nickel-bearing waste materials. Against Accra's Kpone landfill (Fei-Baffoe et al.,

2020), Upper Ekehuan shows 3–5× higher Chromium, reflecting tanning and dyeing waste contributions.

Against EU Landfill Directive limit values, both samples fail comprehensively: Cd limit 0.2 mg/L vs. actual

0.87–0.93 mg/L (4–5× exceedance); Ni limit 0.5 mg/L vs. actual 4.73–7.37 mg/L (9–15× exceedance); Pb limit

0.05 mg/L vs. actual 2.27–3.82 mg/L (45–76× exceedance); Cr limit 0.05 mg/L vs. actual 1.98–3.08 mg/L (40–

62× exceedance).

Source-Pathway-Receptor Analysis

The L:GW ratios for the proximal boreholes (GW1-GW3) vary from 3.2:1 (Iron, indicative of rapid

precipitation) to 8.5:1 (Lead), to 13.3:1 (Nickel), to 22.4:1 (Phosphate). These values are much lower than the

attenuation factors reported for EU regulated landfills with clay barriers (where the typical dilution factors are

100:1 to 1,000:1), confirming the conclusion that there has been little attenuation in the Benin Formation. The

low L:GW ratio for Nickel, for example, indicates a 13.3:1 attenuation, and yet the resulting groundwater Ni

concentrations are still 143-500 times the WHO guideline value. This is why the remediation of groundwater

will be a futile exercise without the control of the leachate source. A 100-fold improvement in the attenuation

capability of the aquifer will still not be enough to lower the Ni groundwater concentrations to within 5-50 times

the WHO guideline value, so long as the leachate source continues to contribute the same concentrations to the

groundwater.

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DISCUSSION

The Decomposition Stage and Contamination Trajectory

The relatively high COD values, combined with the extremely high heavy metal concentrations, point to the

methanogenic/stabilization phase, during which all the bioavailable organic matter has been degraded, but the

inorganic metal contaminants continue to be leached from the waste matrix (Kjeldsen et al., 2002; Youcai, 2021).

This phase lasts for 15-40 years in the tropics (Renou et al., 2022). The contamination trajectory is not an organic

chemistry problem, for which biological treatment would be effective, but a heavy metal problem, for which

physicochemical treatment, such as precipitation, coagulation, and ion exchange, is needed, and for which there

is no infrastructure at the site.

Iron as a Geochemically Mediated Amplifier

Under the acidic and reducing environment, ferrous iron Fe²⁺ is soluble and leaches along with the leachate.

Upon being exposed to the oxidizing environment, Fe²⁺ precipitates out in the forms of ferrihydrite and goethite,

which have high sorption capacities for other heavy metals. However, the spatial decay analysis suggests that

the theoretical advantage is overshadowed by the high concentration of metals, the low co-precipitation surface

area of the sandy matrix, and the constant leachate production that maintains the reducing environment in the

near-source zone (Kjeldsen et al., 2002).

Phosphate Loading and Surface Water Eutrophication Risk

Phosphate leachate concentrations for the two leachates, i.e., L1: 11.34 mg/L, and L2: 8.66 mg/L, pose a risk to

surface water eutrophication, which has not been previously assessed for this dumpsite. The basin terrain and

high rainfall experienced during the rainy season imply a substantial amount of surface runoff into the Ogba

River. The risk assessment indicates that the leachate concentrations have the potential to cause eutrophication,

which will lead to the destruction of the Ogba River water as a supplementary water source for the inhabitants

in the catchment area.

Waste Management Hierarchy Implications

WMH provides a clear hierarchy for the intervention strategy. The hierarchy suggests that the immediate action

is the closure of the dumpsite. In the short term, the dumpsite will need a low-permeability surface cover. This

will involve the construction of a clay cover, which will reduce leachate production by 70–90%, as stated in the

study by Youcai, 2021. In the medium term, the dumpsite will need a leachate collection system. In the long

term, the dumpsite will need to be assessed for resource recovery. This hierarchy is similar to the Global Waste

Management Outlook report by Wilson et al. (2021) that suggests that dumpsite closure is the single most

important intervention that Sub-Saharan African countries need to make in the field of waste management for

the health benefits it will bring to the inhabitants in the catchment area.

Regulatory and Governance Gaps

The presence of an operational dumpsite with generated leachate with a concentration of 62.4–94.7 mg/L

indicates a basic regulatory problem. The NESREA Act of 2007 prohibits indiscriminate disposal of hazardous

waste, and the National Environmental Regulations on Sanitation and Wastes Control of 2009 require leachate

collection and treatment infrastructure, which is absent at the dumpsite.

The economic rationale for intervention is compelling, as the cost of emergency water supply and medical

treatment for illness related to contamination is almost certainly greater than the cost of closing the dumpsite

and leachate collection and containment when the long-term effects of contamination are factored into the

decision. Therefore, there is a compelling need to close the dumpsite and contain the leachate. This is also in

line with the findings of Kaza et al. (2021).

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Policy Recommendations

The Upper Ekehuan dumpsite needs to be closed with the support of the Solid Waste Management Authority of

Edo State and enforced by NESREA. A cover system consisting of compacted clay or geomembrane needs to

be constructed over the waste deposit site within 12 months of closure to prevent leachate generation. A passive

leachate collection system consisting of a perforated pipe French drain network with collection sump needs to

be put in place to collect leachate before it infiltrates groundwater. Leachate treatment needs to be implemented

using a three-stage process consisting of coagulation/flocculation for suspended solids and heavy metal removal,

lime precipitation for heavy metal removal, and biological treatment using constructed wetlands or an aerobic

bioreactor for organic removal. The Federal Ministry of Environment shall formulate and promulgate the

Minimum National Standards for Leachate Management at Solid Waste Disposal Facilities, including the

requirements for the liners, leachate collection and treatment, and leachate quality monitoring, and the imposition

of sanctions on facilities discharging untreated leachate, all based on EU Landfill Directive requirements and

adapted to Nigerian tropical environments.

CONCLUSION

This study reports the first comprehensive characterization, pollution load assessment, and source-pathway-

receptor investigation on the leachate at the Benin City open dumpsite. The findings reveal the leachate to be of

extreme pollution strength (PLI 62.4–94.7, NPI 148.9–226.4) resulting from catastrophic exceedances of WHO

standards for Iron (67–104×), Nickel (237–369×), Cadmium (174–186×), and Chromium(VI) (40–62×).

Comparative study confirmed the Upper Ekehuan leachate to be among the most polluted urban waste leachate

reported in the African literature. The SPR study further confirmed the simultaneous activities of all three

components of the contamination chain: the source, the pathway, and the receptor. The Benin Formation provides

minimal natural protection to the proximal boreholes. This study, based on the Waste Management Hierarchy,

definitively proves that remediation efforts on the downstream contamination will be for naught without primary

intervention on the leachate source, i.e., the dumpsite.

Author Contributions

M.E.O.: Conceptualization, data collection, laboratory analysis, writing—original draft.

A.D.O. , methodology review, writing—review and editing.

O.E.N.,Preview and Review the final work.

ACKNOWLEDGEMENT

The author gratefully acknowledges the moral support provided by my supervisor Prof E.G Imeokparia for his

criticism and guidance.

Funding: This research received no external funding.

Competing Interests

The authors declare no competing interests in relation to this manuscript.

REFERENCES

1. Ademoroti, C. M. A. (1996). Standard methods of water and effluent analysis. Foludex Press.

2. Aghalino, S. O. (2022). Environmental law enforcement in Nigeria: Challenges and prospects. Journal of

Environmental Law & Practice, 35(2), 145–163.

3. Angulo, E. (1996). The Tomlinson Pollution Load Index applied to heavy metal mussel-watch data.

Science of the Total Environment, 187(1), 19–56.

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4. APHA. (1993). Standard methods for the examination of water and wastewater (19th ed.). American Public

Health Association.

5. Asante-Duah, K. (2022). Management of contaminated site problems (2nd ed.). CRC Press.

6. ASTM. (1990). Annual book of ASTM standards: Water and environmental technology. American Society

for Testing and Materials.

7. DEFRA. (2012). Model procedures for the management of contaminated land (CLR 11). UK Department

of Environment, Food and Rural Affairs.

8. European Commission. (1999). Council Directive 1999/31/EC on the landfill of waste. Official Journal of

the European Communities, L 182, 1–19.

9. Fei-Baffoe, B., Nyankson, E., & Dankwah, J. R. (2020). Leachate characterization and pollutant content

of the Kpone landfill, Ghana. Journal of Environmental Chemistry and Ecotoxicology, 12(1), 1–9.

10. Kaza, S., Yao, L. C., Bhada-Tata, P., & Van Woerden, F. (2021). What a waste 2.0: A global snapshot of

solid waste management to 2050. World Bank.

11. Kjeldsen, P., Barlaz, M. A., Rooker, A. P., Baun, A., Ledin, A., & Christensen, T. H. (2002). Present and

long-term composition of MSW landfill leachate: A review. Critical Reviews in Environmental Science

and Technology, 32(4), 297–336.

12. Longe, E. O., & Balogun, M. R. (2021). Groundwater quality assessment near a municipal landfill, Lagos,

Nigeria. Research Journal of Applied Sciences, Engineering and Technology, 2(1), 39–44.

13. Nathanail, C. P., & Bardos, P. (2021). Reclamation of contaminated land. Wiley.

14. Naveen, B. P., Mahapatra, D. M., Sitharam, T. G., Sivapullaiah, P. V., & Ramachandra, T. V. (2022).

Physico-chemical and biological characterization of urban municipal landfill leachate. Environmental

Pollution, 220(Pt A), 1–12.

15. NESREA. (2007). National Environmental Standards and Regulations Enforcement Agency

(Establishment) Act. Federal Government of Nigeria.

16. Njeru, J. (2022). The urban political ecology of the Dandora municipal solid waste dumping site in Nairobi.

Journal of Eastern African Studies, 16(2), 248–268.

17. Nwachukwu, M. A., Feng, H., & Achilike, K. (2021). Integrated studies for dumpsite characterization.

Environmental Geochemistry and Health, 43(2), 611–626.

18. Renou, S., Givaudan, J. G., Poulain, S., Dirassouyan, F., & Moulin, P. (2022). Landfill leachate treatment:

Review and opportunity. Journal of Hazardous Materials, 150(3), 468–493.

19. Tomlinson, D. L., Wilson, J. G., Harris, C. R., & Jeffrey, D. W. (1980). Problems in the assessment of

heavy-metal levels in estuaries. Helgoländer Meeresuntersuchungen, 33(1–4), 566–575.

20. Wilson, D. C., Rodic, L., Modak, P., et al. (2021). Global waste management outlook. UNEP & ISWA.

21. Youcai, Z. (2021). Pollution control and resource recovery: Municipal solid wastes at landfill (2nd ed.).

Butterworth-Heinemann/Elsevier.

22. Zhang, C., Shan, B., Tang, W., & Dong, L. (2021). Heavy metal concentrations and pollution indices in

riparian soils. Environmental Monitoring and Assessment, 189(6), 291.

23. Adewole, M. B. (2023). Urban solid waste management and soil quality in southwestern Nigeria.

Environmental Science & Policy, 142, 45–58.

24. Adesuyi, A. A., Nnodu, V. C., Njoku, K. L., & Jolaoso, A. (2020). Nitrate and phosphate contamination

in groundwater of open dumpsites. Environmental Monitoring and Assessment, 192, 215.

25. Imasuen, O. I., & Omorogieva, O. M. (2013). Comparative study of heavy metals in Benin City. Journal

of Applied Sciences and Environmental Management, 17(3), 425–430.

26. Omorogieva, O. M., Imasuen, O. I., & Sanni, E. B. (2013). Heavy metals in a waste currency dumpsite.

Journal of Science Research, 12, 87–94.

27. Short, K. C., & Stauble, A. J. (1967). Outline of geology of Niger Delta. AAPG Bulletin, 51(5), 761–779.

28. FAO. (2022). The state of food and agriculture 2022. Food and Agriculture Organization.