Environmental Impact of Cement Production in Nigeria

Environmental Impact of Cement Production in Nigeria
1. Introduction
Nigeria has emerged as Africa's largest cement producer, with an estimated installed capacity of approximately 70 million tonnes per annum and current demand of about 33.9 million tonnes . The industry has transformed from an import-dependent sector into a regional production hub, with investments exceeding US$6 billion . This rapid industrialization, however, has brought significant environmental consequences that affect air quality, water resources, soil health, vegetation, and public health across communities hosting cement facilities.
The environmental impact of cement production in Nigeria is particularly pronounced due to the convergence of several factors: the concentration of production facilities in specific geological regions, the proximity of communities to mining and processing operations, and the challenges of regulatory enforcement in a rapidly industrializing economy. The Nigerian cement industry is dominated by major players including Dangote Cement, BUA Cement, and Lafarge Africa, with significant operations in Ogun, Kogi, Cross River, and Edo States .
This assessment examines the multifaceted environmental impacts of cement production in Nigeria, drawing upon recent scientific studies and field investigations to characterize the nature, magnitude, and spatial distribution of these impacts. The analysis addresses air quality degradation, water pollution, soil contamination, vegetation damage, and human health risks, while also considering the industry's contribution to greenhouse gas emissions and the emerging policy responses aimed at mitigation.
2. Air Quality Degradation
2.1 Particulate Matter Emissions
Air quality degradation represents the most visible and extensively documented environmental impact of cement production in Nigeria. Field studies conducted around major cement facilities have consistently found particulate matter concentrations that substantially exceed both Nigerian regulatory standards and World Health Organization guidelines.
A comprehensive assessment of airborne particulate pollution in communities surrounding the Dangote Cement Manufacturing Plant at Obajana, Kogi State, found PM₂.₅ concentrations ranging from 41.2 µg/m³ to 291.6 µg/m³, while PM₁₀ concentrations ranged between 45.4 µg/m³ and 230.1 µg/m³ . These values significantly exceed the WHO 2021 annual guideline for PM₂.₅ of 5 µg/m³, with maximum concentrations approaching sixty times the recommended limit. The study further revealed that communities within 0.5–2 km of the plant recorded the highest pollutant loads, underscoring the influence of proximity on exposure intensity .
The spatial distribution of particulate pollution follows patterns consistent with atmospheric dispersion from point sources. Communities immediately downwind of kiln stacks and material handling operations experience the highest concentrations, with levels declining with distance but remaining elevated well beyond the plant perimeter. The study at Obajana calculated hazard quotient values exceeding unity for most sampling locations, indicating potential non-carcinogenic health effects for exposed populations .
2.2 Fugitive Dust from Mining and Material Handling
Beyond stack emissions, fugitive dust from limestone quarrying, crushing, and material transport represents a significant and often under-regulated source of particulate pollution. Community protests at Tse-Kucha in Gboko Local Government Area of Benue State highlighted the severity of this problem, with residents reporting that limestone dust from Dangote Cement's quarrying operations covers their trees, contaminates water sources, and causes structural damage to buildings through the reverberations of daily blasting .
The environmental manager for Ogun State acknowledged this distinction between stack and fugitive emissions, noting that while stack emissions at the Ewekoro facility were found to be within permissible limits, the mining site presented a different challenge: "They were not able to precipitate the dust from their mining site, not from the stack" . This observation highlights the need for comprehensive dust management strategies that address both point-source and diffuse emission pathways.
2.3 Gaseous Emissions
Cement production also generates gaseous pollutants including carbon monoxide, carbon dioxide, nitrogen oxides, and sulfur dioxide. A study examining the effect of cement production processes on dry atmospheric chemistry at the Lafarge Holcim cement processing plant in Cross River State used mobile real-time air quality monitors to evaluate levels of CO, CO₂, and other pollutants . While specific concentration data were not available in the search results, the study's focus on "monthly variations of air quality" suggests significant temporal variability driven by production cycles and meteorological conditions.
3. Water Resources Contamination
3.1 Surface Water Quality Impacts
The discharge of liquid effluents and contaminated stormwater runoff from cement facilities poses significant risks to surface water resources. A two-year study conducted at Ewekoro, Ogun State, investigated the environmental impacts of cement production on the Akinbo River, which receives the industry's liquid waste and effluents . The water quality analysis revealed elevated concentrations of calcium and iron, with the latter exceeding the recommended limit of 5.0 mg/L for discharge into inland waters .
The elevated iron concentrations were attributed to the leaching of iron ions from particulate matter generated during production processes . This finding demonstrates the interconnected nature of environmental impacts, as airborne dust deposited on land surfaces can subsequently contaminate water resources through runoff and leaching.
3.2 Stormwater Runoff Quality
Analysis of stormwater runoff from a cement facility revealed additional water quality concerns. While most physicochemical parameters fell within limits set by the National Environmental Standards and Regulations Enforcement Agency (NESREA), exceptions included elevated pH values above 9.0 in several samples, exceeding the NESREA limit of 6.0–9.0 . Sulfate concentrations in three samples exceeded the 250 mg/L NESREA limit, reaching values as high as 540 mg/L .
Heavy metal contamination in stormwater runoff was also documented. Copper, zinc, and lead concentrations in one sample exceeded recommended limits, with lead at 0.08 mg/L compared to the NESREA limit of 0.05 mg/L . Iron concentrations reached 19.73 mg/L in one sample, nearly four times the permissible limit. These findings indicate that cement production facilities can serve as sources of heavy metal contamination to receiving water bodies even when individual process streams comply with discharge standards.
3.3 Groundwater and Drinking Water Risks
The contamination of water sources extends beyond surface waters. A study assessing heavy metal contaminants in water and soil at the vicinity of United Cement (UNICEM) in Mfamosing, Cross River State, examined tap water and soil samples from three locations near the factory . While most physicochemical parameters of water fell within WHO limits for potable water, exceptions included elevated levels of phosphate. The heavy metal concentrations in water ranked as Cr > Ni > Cu > Zn > Cd > Pb .
Critically, the calculated cancer risk and total cancer risk values exceeded the acceptable range limit of 1×10⁻⁶ to 1×10⁻⁴, indicating a predisposition to toxic metal toxicity and potential cancer development . This finding has significant implications for communities relying on groundwater or surface water sources for drinking and domestic use.