Journal of Applied Physical Science International

Geological Occurrence and Distribution of Heavy Metals in Nigerian Coal and Clay: Industrial, Environmental, and Health Implications: A Review

Nsikan J. Etukudo — 2026-07-13

Heavy metals are naturally occurring elements that can become environmentally hazardous when present at elevated concentrations. Coal and clay are among Nigeria's most important geological resources, contributing significantly to energy production, industrial development, construction, and ceramic manufacturing. However, these materials also contain varying amounts of heavy metals that may be released into the environment during mining, processing, utilisation, and disposal. This review examines the geological occurrence, distribution, and concentration of heavy metals in Nigerian coal and clay deposits and discusses their industrial, environmental, and health implications. The reviewed studies reveal considerable variations in heavy metal concentrations across different deposits due to differences in geological setting, mineral composition, and depositional history. Nigerian coal deposits generally contain higher concentrations of heavy metals than clay deposits. Manganese concentrations in coal range from 6.06 to 783.93 mg/kg, nickel from 39.69 to 85.38 mg/kg, chromium from 7.14 to 36.57 mg/kg, copper from 67.21 to 94.93 mg/kg, and strontium from 24.08 to 383 mg/kg. In contrast, clay deposits typically contain lower concentrations, with copper ranging from 0.113 to 1.228 mg/kg, zinc from 2.972 to 4.755 mg/kg, lead from 0.731 to 2.193 mg/kg, nickel from 0.712 to 5.25 mg/kg, and cadmium reaching 2.80 mg/kg in some locations. Elevated mercury and cadmium levels have also been reported in certain edible clays. The findings indicate that coal poses a greater risk of heavy metal release through mining, combustion, and fly ash generation, whereas clay-related concerns are mainly associated with industrial applications and geophagic consumption. Continuous monitoring, effective environmental management, and stricter regulatory measures are therefore essential for sustainable resource utilisation and the protection of public health.

Data Flow Modeling Framework for Cloud-Native Systems Engineering: An Intelligent Approach for Microservices and Secure Data Pipelines

Tom Innocent Okpong — 2026-07-03

Cloud-native systems increasingly rely on microservices, container orchestration, distributed data pipelines, and continuous monitoring to support scalable and resilient software operations. However, the distribution of services across dynamic infrastructure environments creates persistent challenges in data flow management, latency control, security enforcement, anomaly detection, and resource utilisation. This study proposes an Intelligent Data Flow Modelling Framework for cloud-native systems engineering. The framework integrates Microservices Architecture, Secure Data Pipelines, and Artificial Intelligence Monitoring through an Intelligent Data Flow Management layer designed to improve Cloud-Native System Performance. A design science research approach was adopted to develop the framework as a conceptual engineering artefact. The proposed architecture consists of cloud-native infrastructure, intelligent data flow, secure pipeline, AI monitoring and analytics, and optimisation and decision layers. The framework incorporates mathematical components for anomaly detection, data flow efficiency, security risk assessment, and resource utilisation efficiency. Simulation-based analysis was used to illustrate the potential behaviour of the proposed framework under varying workload conditions. The results suggest that the integrated approach may support improved throughput, controlled latency, high availability, anomaly detection, and workload-aware resource use under the modelled scenarios. In addition, a structural validation model is presented to guide future empirical assessment of the relationships among architectural, security, monitoring, data flow, and performance constructs. The study contributes a unified conceptual framework for secure and intelligent management of data flows in cloud-native environments. The findings should be interpreted as simulation-based and illustrative and require further validation in real-world production systems.

Eco-friendly Bio-carbon Doped ZnO Thin Films: Structural, Optical, and Humidity Sensing Properties

Muatazbullah Ibrahim Abdullah — 2026-07-07

Bio-carbon-doped ZnO thin films were prepared using bio-carbon extracted from pomegranate peels and deposited on glass substrates by spray pyrolysis. The study examined the influence of bio-carbon doping, ranging from 0 to 7.5 wt.%, on the structural, morphological, optical and humidity-sensing properties of the films. X-ray diffraction analysis indicated that all films retained the hexagonal wurtzite structure of ZnO without secondary phases. Increasing bio-carbon content reduced the crystallite size from 29.5 to 25.4 nm and increased microstrain and dislocation density, indicating the introduction of structural defects and lattice distortion. FESEM and AFM analyses showed compact granular surfaces, reduced grain size and increased surface roughness, with roughness increasing from 5.20 to 9.80 nm. FTIR spectra confirmed the presence of Zn-O bonds and carbon-related functional groups, suggesting interaction between bio-carbon components and the ZnO surface. Optical measurements showed enhanced absorbance and a gradual reduction in the optical band gap from 3.28 to 3.09 eV. Humidity-sensing measurements demonstrated improved performance with increasing bio-carbon concentration. The film doped with 7.5 wt.% bio-carbon showed the highest sensitivity of 82% and response/recovery times of 14 s and 18 s over 20–90% relative humidity. The findings indicate that pomegranate-peel-derived bio-carbon can enhance ZnO thin-film properties for low-cost humidity-sensing applications.

Surface Water Characteristics and Trace Metals Concentration of Woji River, Port Harcourt, Rivers State, Nigeria

Ojutemieden, Daniel Onajite — 2026-07-10

Surface water quality in the Woji River, Port Harcourt, Rivers State, Nigeria, was assessed using selected physicochemical parameters and trace metals. Six surface water samples were collected from different points along the river and analysed using standard laboratory procedures. The measured physicochemical parameters showed spatial variation across the sampling points. The pH ranged from 4.0 to 4.8, indicating acidic conditions. Electrical conductivity ranged from 210.1 to 2817 µS/cm, while salinity varied from 3.5 to 5.1%. Alkalinity ranged from 350 to 403 mg/L, chloride from 385.8 to 458 mg/L, nitrate from 2.5 to 3.5 mg/L, phosphate from 0.7 to 1.5 mg/L, and hardness from 208.6 to 320.3 mg/L. Total organic matter ranged from 18.5 to 26.0%, total organic carbon from 10.7 to 15.0%, nitrogen from 2.1 to 3.2%, and oil and grease from 7.671 to 20.43 mg/L. Trace metal concentrations varied among sampling points, with copper ranging from 0.005 to 0.012 ppm, cadmium from 0.035 to 0.057 ppm, iron from 0.088 to 0.120 ppm, lead from 0.065 to 0.080 ppm, chromium from 0.015 to 0.031 ppm, cobalt from 0.175 to 0.219 ppm, vanadium from 0.081 to 0.112 ppm, potassium from 35.561 to 56.988 ppm, and nickel from 0.010 to 0.100 ppm. The pH, electrical conductivity, chloride, oil and grease, cadmium, lead, cobalt, vanadium, and nickel values were above the WHO regulatory limits in some of the analysed water samples. The findings indicate that Woji River is affected by anthropogenic inputs and requires regular monitoring to support environmental management.