Asian Journal of Environment & Ecology

Mammalian Toxicity of Some Commercially Commonly Used Plant Growth Regulators: A Comprehensive Review

Krishnanjana V.J. — 2025-10-22

Plant growth regulators (PGRs) have become an integral part of modern agriculture for enhancing the yield and quality of crops. Plant growth regulators, or exogenous plant hormones, are a class of artificial compounds that behave physiologically similar to endogenous plant hormones. However, concerns persist regarding their residue level in crops and potential adverse effects on mammalian health. Persistence of plant growth regulator residues in crops raises apprehensions about their consumption by humans and livestock. Various studies have identified hepatotoxic and nephrotoxic effects, reproductive toxicity, carcinogenicity linked to specific plant growth regulators, emphasising the importance of understanding the mechanisms and dose-response relationships involved, which is an essential part for assessing the risks and designing mitigation strategies. Further research is imperative to bridge knowledge gaps, ensuring the judicious and safe use of PGRs in modern agriculture. As awareness of the hazardous effects of PGRs grows, there is a growing interest in sustainable and environmentally friendly alternatives for plant management, which can be provided by biostimulants.

From Tremors to Threats: A Systematic Review of Nigeria’s Earthquake Vulnerability, Urban Exposure and Governance Readiness (1990-2025)

Bello Hafisat Omodasola — 2025-10-11

Earthquake risk in Nigeria has historically been underestimated, yet recurrent tremors over the past decades reveal emerging vulnerabilities that demand systematic attention. This review synthesizes evidence of seismic vulnerability in Nigeria between 1990 and 2025, with emphasis on hazard patterns, urban exposure, socio-economic drivers, and governance frameworks.

Aim: To synthesize evidence of seismic vulnerability in Nigeria (1990-2025), examining hazard patterns, urban exposure, socio-economic factors, and governance frameworks.

Study Design: Systematic review guided by PRISMA.

Place and Duration of Study: Nigeria; literature published between 1990 and 2025.

Methodology: Guided by PRISMA standards, ≈200 records were initially identified from multidisciplinary databases and institutional repositories. After screening and eligibility checks, 61 studies were retained and thematically coded across four domains: seismic hazard characterization, urban and infrastructural exposure, socio-economic vulnerability, and policy/governance. Comparative insights were drawn from African and global contexts, supported by Geographic Information System (GIS) overlays.

Results: Findings show seismic hotspots in southwestern cities (Ibadan, Akure), central hubs (Abuja, Kaduna), and southern zones (Bayelsa, Edo). Isolated tremors in Bauchi, Maiduguri, and Enugu highlight under-monitored risks. Most events are low-magnitude, yet impacts are amplified by rapid urbanization, fragile building stock, weak enforcement of codes, and limited preparedness. Comparative insights from East Africa, Brazil, and Nepal emphasize how governance and community resilience are as critical as geophysical hazards.

Conclusion: Nigeria’s seismic risk, though low frequency, is significant due to compounded vulnerabilities. Strengthening monitoring networks, embedding hazard-informed urban planning, enforcing building codes, and promoting community preparedness are urgent priorities. Future research should integrate advanced tools such as GeoAI and remote sensing for high-resolution hazard modeling and multi-scalar vulnerability mapping.

Optimization of Seed Quality, Germination and Nursery Performance of Butea monosperma (Lamk.) Taub. for Sustainable Propagation and Conservation

Manish Kumar Vijay — 2025-09-25

Butea monosperma (Lamk.) Taub. is an ecologically and economically important tree, yet its propagation is hindered by inconsistent seed quality, variable germination, and lack of standardized nursery and storage practices. This study examined seed maturation, germination ecology, nursery propagation, and storage behavior to optimize seedling performance and conservation strategies. Fruits and seeds were collected at successive stages of development and evaluated for morphological and physiological traits, germination responses, and seedling vigor. Results indicated that optimum maturity occurred at 70–80 days after anthesis, with seeds showing maximum germination and vigor. Germination was strongly influenced by temperature, light, and substrate, with favorable conditions enhancing early seedling growth. Nursery trials revealed that a Soil: Sand: FYM mixture (1:2:1) produced the most vigorous seedlings with superior growth and biomass. Storage experiments demonstrated that drying seeds to ~3–4% moisture and maintaining them at 5 °C preserved viability and vigor effectively over time. Seed source variation had minimal influence on germination and early growth, indicating wider applicability of the optimized protocols. This study provides practical guidelines for seed collection, propagation, and conservation of B. monosperma, supporting large-scale regeneration, ecological restoration, and sustainable management of this valuable species.

The Spatio- Temporal Changes in Water Quality and Influences on the Phytoplankton, Zooplankton and Fish Species in Four Large Riverine Ecosystems in Lake Victoria Basin, Kenya

Job Mwamburi — 2025-09-26

Rivers and streams in the Lake Victoria Basin (Kenya) (LVBK) are vital for aquaculture, irrigation, hydropower, domestic use, and biodiversity conservation. However, increasing population, urbanization and pollution, and changes in landuse/landcover are factors that contribute to the modification of the riverine habitats which also serve as fish breeding areas. There are increasing concerns on the potential loss of biodiversity juxtaposition the expanding anthropogenic pressures but gaps exists on information available. This study was conducted during the persistent heavy short rains (November 2019) and dry conditions (March 2020), and was used to assess the environmental conditions of rivers Nzoia, Yala, Awach and Nyando using indices of physico-chemical parameters, nutrient levels, plankton, aquatic macro-invertebrate assemblages and fish species composition and abundance. Structural and abiotic differences were found in selected site habitats due to the high gradient variation from the lake shore areas. River drainage basins are extensive and under heavy agricultural and human activities with reduced soil cover which contributes to increasing loading of eroded soils and materials which impact the quality of surface water. We identified significant spatio-temporal variations in nutrient levels, biodiversity, and water quality indices across four major rivers, highlighting hotspots of eutrophication and biodiversity vulnerability. Sampled rivers exhibit high turbidity with variable concentrations of nutrient elements downstream. Results show seasonal and anthropogenic influences on the water quality in all the river channels, which is likely to impact resident species. The high abundance of diatoms and chlorophytes as dominant phytoplankton families, is an indication of cultural eutrophication. Turbidity favors the dominance of diatoms especially centric diatoms which are able to attach on detritus. Eight fish families (with 19 fish species) were found and were dominated the Cyprinidae group. We recommend improved catchment management, agricultural practices and protection existing forest areas with long-term river monitoring program.

Geo-Environmental Impacts of Gully Erosion in Ezeoke Nsu, Southeastern Nigeria

Umueni Uchenna Elizabeth — 2025-09-27

In southeast Nigeria, gully erosion is one of the worst types of land degradation, presenting serious problems for the geoenvironment, the economy, and the infrastructure. Examining the geoenvironmental effects of gully erosion in Ezeoke Nsu, a village in Imo State, southeast Nigeria, where intensive land use practices, high rainfall, and weak geology have made soil loss more common, is the focus of this study. The study used GIS tools, laboratory analysis, field surveys, and soil sampling to determine the extent, causes, and effects of gully erosion in the region. Gully start and expansion are largely caused by unconsolidated sandy soils, steep terrain, and human activities such deforestation, inadequate land management, and unplanned settlements, according to the results.Gully erosion in Ezeoke Nsu has a variety of effects. In terms of the environment, it causes biodiversity loss, disturbance of natural drainage systems, and the loss of fertile topsoil. Gully extension has harmed highways, wrecked farmlands, endangered residential buildings, and made communities more susceptible to flooding. In terms of the economy, it damages agricultural output, lowers household income, uproots families, and fuels food insecurity. Additionally, the community's settlement stability and sustainable development are at long-term risk due to the gullies' ongoing growth.The study comes to the conclusion that in order to lessen the damaging impacts of gully erosion, immediate, integrated erosion control measures—such as reforestation, check dam construction, and appropriate land-use planning—are required. Policymakers, environmental managers, and local stakeholders can utilize the findings to inform the development of sustainable land management plans that safeguard livelihoods and the environment in southeast Nigeria.

Village SDGs and Environmental Resilience: Evaluating Sustainable Development in Underdeveloped Villages, Manokwari Regency, West Papua Province, Indonesia

Yulianus Ayok — 2025-10-03

Development inequality and ecosystem vulnerability remain major challenges in achieving sustainable development in underdeveloped villages, particularly in West Papua Province. This study aims to evaluate the contribution of the Village Sustainable Development Goals (SDGs), specifically SDG 2 (Zero Hunger), SDG 6 (Clean Water and Sanitation), and SDG 10 (Reduced Inequalities), to the Environmental Resilience Index (ERI). The research was conducted in underdeveloped villages in Manokwari Regency using a case study approach and qualitative-comparative analysis based on 2023 Village SDGs data and the Village Development Index (VDI) status. Results indicate that villages classified as very underdeveloped (ERI 67.18 ± 2.25) and underdeveloped (65.56 ± 1.61) record similar resilience levels, although some very underdeveloped communities show unexpectedly high ERI scores, reflecting the influence of local socio-ecological assets. Food security (SDG 2) appears relatively strong in very underdeveloped villages due to reliance on traditional subsistence systems, while both categories face persistent deficits in water and sanitation (SDG 6). Inequality reduction (SDG 10) records the lowest performance overall. Regression analysis shows that SDG 2, SDG 6, and SDG 10 jointly exert a marginally significant influence on ERI (ANOVA, F = 2.830; p = 0.060, α = 0.10), explaining 26.1% of variation. Among them, SDG 10 has the strongest positive effect (β = 0.527, p = 0.012). These findings highlight the need for asset-based, cross-sectoral, and context-sensitive strategies to enhance resilience and reduce inequality in marginalized rural areas.

Assessment of Background Radiation Level at Dumpsites in Ogwashi-Uku and its Environs in Delta State, Nigeria

B.O. Ijabor — 2025-10-04

This study assesses background radiation levels at six dumpsites in Ogwashi-Uku and its environs in Delta State, Nigeria, using a calibrated Geiger-Muller counter. Obtained readings were used to calculate equivalent dose rate (EDR), absorbed dose rate (ADR), annual effective dose rate (AEDR), and excess life time cancer risk (ELCR). Measurements revealed that while average outdoor background ionizing radiation (BIR) and EDR was below recommended levels, absorbed dose rates (ADR), annual effective dose equivalent (AEDE) and excess lifetime cancer risk (ELCR) estimates exceeded global averages. The maximum outdoor BIR (0.018 mRhr^-1) was in Ogwashi-Uku market dump 1 and is above the United Nation Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) mean value of (0.013 mRhr^-1). The background ionizing radiation from these dumpsites were exactly same as the value recommended in the (UNSCEAR) report, but EDR, AEDE and ELCR were higher compared to recommended values highlighting urgent needs for improved waste management practices in order to reduce its effects on the local populace working and living around the dumpsites.

Human Health Risk Assessment of Polychlorinated Biphenyls (PCBs) in Fish from Eniong River, Nigeria

Rosemary Boniface Udombeh — 2025-10-06

Eniong River is an important source of seafood at commercial levels. Riverine communities also depend on it for other domestic uses. Potential human activities in the study area include boating, fishing, sand mining, and transportation, among others. These PCB-induced activities have been going on in the study area over the years, and there is no research data on PCB levels in fish in the area; hence, the need for this research. The objective of this study was to determine the concentration and distribution of PCBs in fish and sediment samples from the Eniong River. The determination of PCBs in fish samples from the river was done using standard procedures. Fish samples (96) (Clarias gariepenius) were collected from four sampling locations for twelve months. Extraction of samples was done using dichloromethane, hexane, and acetone. PCBs (28) congeners were determined using gas chromatography equipped with a mass spectrometer (GC-MS). The data obtained in this study were subjected to descriptive statistical analysis using the Statistical Package for the Social Sciences (SPSS). Analysis of variance (ANOVA) was used to test for significant differences in PCB concentrations across the sampling stations at P = 0.05. The results showed that the total PCBs (∑ 28 PCBs) concentrations in fish ranged from 30.26 to 107.07ngg^-1. The hazard index values for non-cancer risk were less than unity, while the total cancer risk values were less than 10^-6, indicating low risk. However, the toxic equivalent quotient of 12 DL- PCBs ranged from 4.6 E-03 to 2.7 E-02 ngg^-1, indicating values greater than the upper limit of 6.5 E-03 stipulated by the European Food Safety Authority (EFSA) for all Dl PCBs in fish. Although the homolog composition did not differ significantly between the two seasons (p > 0.05). Most of the homologues recorded higher values in the wet season compared with the dry season. As a precautionary measure, the results indicated the need for urgent intervention to prevent escalation in levels of the pollutants in the commercial fish.

Assessment of Environmental and Anthropogenic Drivers of Heavy Metal and Hydrocarbon Pollution in Oguta Lake, Nigeria: Seasonal Variability and Comparative Analysis

Ozoh Kingsley Chidiebere — 2025-10-07

This study assessed the environmental and anthropogenic factors influencing heavy metal (HM) and total petroleum hydrocarbon (TPH) pollution in Oguta Lake, Imo State, Nigeria, with Abadaba Lake serving as a control. A mixed-method approach was adopted, combining field sampling of water and sediments over one year (April 2023–February 2024) with a questionnaire survey of 271 residents. Samples were collected in both wet and dry seasons and analysed following APHA (1999) standards. Descriptive statistics, Chi-square tests, and two-sample t-tests were applied to evaluate patterns and seasonal variations. Survey results indicated that oil and gas activities (38%), agricultural runoff (24%), crude oil loading (20%), and domestic waste disposal (18%) were the major contributors to contamination. Laboratory findings showed that TPH concentrations ranged from 0.07–45.20 mg/L, with no significant seasonal difference (p > 0.05). In contrast, heavy metals displayed notable variations: Pb (0.42–1.15 mg/kg), Cr (0.31–0.89 mg/kg), and Cd (0.02–0.11 mg/kg) were significantly higher in sediments during the dry season (p < 0.05), while Ni (0.15–0.44 mg/kg) was elevated in the wet season. Iron (Fe) remained consistently high across both seasons. The results highlight sediments as a more reliable indicator of pollution trends, underscoring the urgent need for stronger regulatory control of oil-related activities and improved waste management practices around Oguta Lake.

Biodiversity of Bird Species in the Work Area PT. Sinar Mas Agro Resources and Technology Tbk., Papua Region

Basa T. Rumahorbo — 2025-10-13

The research aims to determine the biodiversity of bird species in the work area of PT. Sinar Mas Agro Resources and Technology Tbk., Papua Region. The research was conducted in July – December 2024 in the High Conservation Value Area (HCV) owned by PT. Sinar Kencana Inti Perkasa (SKIP) and PT Sumber Indah Perkasa (SIP) Papua Lereh Region, Kaureh District, Jayapura Regency. The results of the inventory of bird diversity and population density showed that there were 59 species of birds from the Acipitridae family, 7 species from the Psittaculidae family, and 4 species from the Columbidae family. The observation location with the highest number of individuals was found at station A, namely 24 types from 15 families; Station G as many as 18 types from 10 families; and Station B as many as 24 species from 13 families The bird diversity index values for all locations ranged from medium to high with a Shannon-Wienner index value H' = 2.590 – 3.681. The highest score was at station F with H'= 3.6811station I with H'= 3.543; and station B with H'= 3.201. Based on their conservation nature, 42 species of birds are in protected status based on applicable laws and regulations, 58 species are classified as LC and NT categories according to IUCN, 37 species are classified as Appendix I and II categories of CITES, 14 species are classified as endemic birds of Papua and 2 types of migratory birds. The Yellow Paradise Bird (Paradiseae minor) which is an endemic bird was found at 7 observation stations.

Estimation of Biomass and Carbon Storage in Trees of the Char Kukri Mukri Mangrove Forest in Bhola District, Bangladesh

Md. Ashrafur Rahman Bhuiyan — 2025-10-16

The estimation of biomass and carbon stored by the trees in the Char Kukri-Mukri mangrove forest ecosystem of Bhola district of Bangladesh, was conducted during 2023 to 2024. The total recorded values of AGTB, BGTB, TTB, and TCS 145.3 tonh^-1, 29.06 tonh^-1, 174.36 tonh^-1, and 63.21 tonh^-1 in site-1; 671 tonh^-1, 134.2 tonh^-1, 805.2 tonh^-1, and 291.88 tonh^-1 in site-2; 252.6 tonh^-1, 50.52 tonh^-1, 303.12 tonh^-1, and 109.88 tonh^-1in site-3; 378.9 tonh^-1, 75.78 tonh^-1, 454.68 tonh^-1, and 164.82 tonh^-1 in site-4; 394.9 tonh^-1, 78.98 tonh^-1, 473.88 tonh^-1, 171.78 tonh^-1 in site-5; 452.1 tonh^-1, 90.42 tonh^-1, 542.52 tonh^-1, and 196.66 tonh^-1 in site-6; 308.1 tonh^-1, 61.62 tonh^-1, 369.72 tonh^-1, and 134.02 tonh^-1 in site-7; 634.2 tonh^-1, 126.84 tonh^-1, 761.04 tonh^-1, 275.88 tonh^-1 in site-8. The total values of aboveground tree biomass (AGTB) of selected sites were found to show a range between 145.3 tonh^-1 and 671 tonh^-1. The maximum AGTB value 671 tonh^-1 was recorded from site-2, whereas the minimum AGTB value of 145.3 tonh^-1 was recorded from site-1. Similarly, the total values of belowground tree biomass (BGTB) of selected sites were found to show a range between 29.06 tonh^-1 and 134.2 tonh^-1. The maximum BGTB value 134.2 tonh^-1 was recorded from site-2, whereas the minimum AGTB value of 145.3 tonh^-1 was recorded from site-1. The values of TCS of selected sites were found to show a range between 63.21 tonh^-1 and 291.88 tonh^-1. The maximum TCS value 291.88 tonh^-1 was recorded from site-2, whereas the minimum TCS value of 63.21 tonh^-1 was recorded from site-1. As a coastal mangrove ecosystem, Char Kukri-Mukri possess high amount of biomass which indicates accumulation of good amount of carbon. This is a highly productive ecosystem that plays critical role to protect and stabilize the coastal mangrove zones of Bangladesh.

Short-Term Health Effects of Fine Particulates from Dust Events in Al-Ahsa, Saudi Arabia: A Simulation-Based Analysis

Zakiah Al-hajji — 2025-10-21

In the Eastern region of Saudi Arabia, dust events are common and pose serious threats to respiratory health. This study evaluated the short-term impacts on respiratory morbidity in Al-Ahsa, Saudi Arabia, of fine particles (PM₂.₅ and PM₁₀) during dust events. A simulation-based framework was used to assess hospital data from 2019 to 2022, by redistributing seasonal hospital visits into daily counts based on the intensity of dust events. The Copernicus Atmosphere Monitoring Service (CAMS-EAC4) provided the daily particulate concentrations, and negative binomial and distributed lag models (0–5 days) were used to assess the relationships between dust intensity, particulate matter, and respiratory visits. The findings indicated that while PM₁₀ showed modest but significant impacts (+8%), same-day increases in PM₂.₅ were strongly associated with higher respiratory visits (≈+16%, p < 0.001). Impacts that were delayed for more than a day were negligible, suggesting that morbidity maxima happen right after exposure. Urban and pediatric hospitals experienced the largest spikes during severe occurrences. Daily-level analysis better captures acute health impacts than seasonal models, which showed weaker or nonsignificant relationships. All things considered, the short-term pulmonary impacts of dust events in Al-Ahsa are primarily caused by fine particles, underscoring the significance of focused public health preparedness and integrated air-quality monitoring in Saudi Arabia.

Preliminary Study on Using Spent Mushroom Substrate (SMS) for Biodegradation of Plastic Waste by Weight Parameter

Nmom, F. W — 2025-10-27

Plastic waste pollution poses significant challenges and harm to both the environment and human health. Plastics accumulate in the environment and recent researches are focused on developing effective eco-friendly biological process to degrade and remove them. It is on this premise that this preliminary assessment of the ability of Spent Mushroom Substrate (SMS) to degrade plastics by weight parameter technique was carried out. Polyethylene terephthalate (PET) was dried at 24°C for 3 days and afterwards cut into bits of 0.06g. These were later immersed in conc. HCl and incubated in microcosm (micro boxes) containing 400g weathered SMS. These boxes were kept in humid dark environment and samples were collected and analyzed after 30 and 60 days. The results revealed that the SMS had significant effect on weight parameters after 30 and 60 days. Microcosm which had an initial weight of 1.20g was biodegraded to 0.16g and individual piece of the plastic in the box with initial weight of 0.06g decreased to 0.04g after 30 days incubation in SMS. Further incubation for 60 days resulted in the decrease of plastic in the box from 1.20g to 0.02g and individual piece from 0.06g to 0.008g. The control maintained the initial weight till the end of the experiment. This is an indication that the mushroom mycelia in the SMS may have had an interface with the plastic polymer. And this seem to be a promising ecofriendly alternative to deal with plastic waste pollution.

Assessment of Heavy Metal and Hydrocarbon Contamination in Sediment and Water of Oguta Lake, Imo State, Nigeria

Ozoh Kingsley Chidiebere — 2025-10-27

This study assessed the levels of Total Petroleum Hydrocarbons (TPH) and selected heavy metals (Pb, Cr, Cd, Ni, and Fe) in the sediments and waters of Oguta and Abadaba Lakes between April 2023 and February 2024, with Abadaba Lake serving as a comparative reference. 144 composite samples of water and sediment were analysed using an Atomic Absorption Spectrophotometer and a Gas Chromatography-flame Ionisation Detector (GC-FID), following American Public Health Association (APHA, 1999) standards. pH results revealed that Oguta sediments remained acidic (< 7.0) throughout the study, while Abadaba sediments shifted from acidic to alkaline conditions after October 2023. In both lakes, water samples were alkaline across the period. TPH concentrations were significantly higher in Oguta sediments (36.43 – 49.95 mg/kg) compared to Abadaba sediments (1.40 – 2.67 mg/kg). Similarly, heavy metals were consistently more elevated in Oguta sediments, with peak levels recorded in February 2024 for Pb (0.194 mg/kg), Cr (0.198 mg/kg), Cd (0.116 mg/kg), and Fe (134.73 mg/kg). Water samples showed lower concentrations of TPH and metals than sediments, but Oguta waters still exhibited higher contamination than Abadaba waters. Comparisons with Nigerian Upstream Petroleum Regulatory Commission (NUPRC) standards revealed that TPH and metal concentrations were within permissible limits in both sediments and water. However, two-sample t-tests showed statistically significant differences (p < 0.05) in contaminant levels between Oguta and Abadaba Lakes, confirming higher pollution in Oguta. These findings underscore the impact of anthropogenic activities around Oguta Lake and emphasise the importance of ongoing environmental monitoring.

Enhanced Sonochemical Degradation of Rhodamine B in Aqueous Solutions: The Role of Additives

Jahangir Hossain — 2025-10-28

In the last few years, the control of water pollution due to hazardous dyes has become increasingly important. Sonochemical degradation has recently been reported as an appropriate and attractive process for the treatment of toxic dyestuffs. This study investigates the breakdown of dye molecules in aquatic media using ultrasonic irradiation to clarify the degradation mechanism. Experiments were conducted in a 50–60 Hz ultrasonic reactor with 100 mL dye solutions at the concentration of 25 mg/L. The effects of various additives, including inorganic salts (FeSO₄, NaCl, Na₂SO₄, NaNO₃), hydrogen peroxide, carbon tetrachloride, Glucose, and Sucrose, the sonochemical degradation of Rhodamine B (RhB) was investigated.

Results showed that degradation was highly influenced by the initial concentration of the substrate and pH. Addition of FeSO₄ enhanced RhB degradation, while increased CCl₄ concentrations accelerated removal through oxidant chlorine species. Presence of H₂O₂ and Na₂SO₄ also improved the degradation efficiency. NaCl and NaNO₃ also enhanced the degradation. However, higher glucose and sucrose concentrations marginally decreased the breakdown efficiency, indicating that radiation from ultrasonic waves remains an encouraging approach for the removal of RhB, even in complex aqueous systems.