Asian Journal of Environment & Ecology

Delineating Ecologically Important Fish Habitats Using Ichthyoplankton Assemblages in the Coastal Waters of Tam Hai, Central Vietnam

Tran Cong Thinh — 2026-08-28

Fish eggs and larvae provide biological information for identifying areas associated with spawning and early development, yet ichthyoplankton remains poorly documented in tropical estuarine–coastal systems. This study examined ichthyoplankton at 16 stations in the coastal waters of Tam Hai, central Vietnam, during the dry season (April 2022) and rainy season (December 2022) to assess taxonomic composition, abundance, spatial organisation, seasonal variation, and associations with surface salinity. A total of 20,888 fish eggs and 1,812 fish larvae were collected, with 24 larval families identified. Mean fish egg density was substantially higher in the dry season than in the rainy season (634.30 ± 157.10 versus 60.18 ± 25.23 eggs/100 m³), while mean larval density was 50.28 ± 15.03 and 20.20 ± 5.71 ind./100 m³, respectively. Larval assemblage composition showed marked seasonal turnover and spatial differentiation across mangrove, transitional, and coral reef-associated habitats. Salinity was significantly associated with the abundance of four larval families: Gobiidae showed a negative association, whereas Nemipteridae, Dorosomatidae, and Terapontidae showed positive associations. The spatial separation between egg-rich and larva-rich stations indicates that early-life-stage distributions may reflect processes operating after spawning as well as habitat conditions. These findings provide baseline information for identifying areas associated with fish spawning and early development and for supporting fisheries conservation and ecosystem-based coastal management.

Assessment of Pest Pressure and the Severity of Attacks by Rice (Oryza sativa L.) Insect Pests in the Maniema Production Basins, Democratic Republic of the Congo

Adiyo Sumbu Henriette — 2026-08-28

Rice (Oryza sativa L.) production in the Democratic Republic of the Congo faces significant biotic constraints, particularly attacks by insect pests that hinder yield stability.

Aims: To evaluate the spatial variability of agro-morphological traits, pest pressure, and the severity of damage caused by insect pests to rainfed rice (Oryza sativa L.) across major production basins in Maniema Province, Democratic Republic of the Congo, to inform targeted integrated pest management strategies.

Study Design: A multi-site comparative field evaluation combining agro-morphological measurements with a quantitative phytosanitary diagnosis.

Place and Duration of Study: Agricultural fields across the production basins of Kailo, Kasongo, and Kibombo, Maniema Province, Democratic Republic of the Congo, during the crop maturity phase.

Methodology: A two-stage stratified sampling scheme was implemented across 384 rice fields (128 per basin), with 10 randomly selected plants evaluated per field (N = 3,840 plants). Recorded agronomic parameters included plant height, collar diameter, tiller count, and panicle grain load. In situ visual counts were used to assess pest abundance, infestation rate, and attack incidence. Qualitative canopy sweep sampling (n = 176) was used to identify pest taxonomic structure. Foliar and panicle attack severity were scored on a 0–9 scale to compute McKinney’s severity index (I_s). Data were analysed using ANOVA, Tukey’s HSD test, Pearson’s chi-square (χ2) test, and ecological diversity indices in R.

Results: Plant height was homogeneous across basins (1.25 to 1.31 m; p = 0.0351), whereas collar diameter, tiller count, and grain load showed significant spatial variation (p < 0.001). Orthoptera dominated the entomofauna (60.80%), led by Oxya hyla (31.25%), followed by Hemiptera (15.34%). Kailo achieved the highest grain load (139.13 ± 23.92 grains/panicle) but had high grain damage (3.66 ± 1.72 grains/sample). Kibombo emerged as the primary epidemic hotspot, exhibiting the lowest Pielou evenness (J’= 0.68), the highest mean pest abundance (1.16 ± 1.46 ind./plant; p = 8.37 times 10-13), a 57.97% infestation rate, 88.05% attack incidence, and an alarming McKinney index of 53.03% (compared to 18.05% in Kailo and 20.56% in Kasongo).

Conclusion: Entomological pressure and damage severity in rainfed rice are highly spatially dependent in Maniema. Kibombo requires urgent, localised intervention focusing on cultural controls and targeted biopesticides during tillering, whereas Kailo requires monitoring against sucking pests during grain filling.

Length-weight Relationship and Condition Factor of Labeo rohita (Hamilton, 1822) and Oreochromis mossambicus (Peters, 1852) Reared in a Floating-Raft Aquaponics System

Vikas Kumar Ujjania — 2026-09-03

Aims: To evaluate and compare the length-weight relationship and modified condition factor of rohu (Labeo rohita, T₁) and Mozambique tilapia (Oreochromis mossambicus, T₂) reared in a floating-raft aquaponics system.

Study Design: Comparative experimental evaluation of biometric performance and body condition of two fish species under floating-raft aquaponics conditions.

Place and Duration of Study: Research Laboratory (Wet Lab), Department of Aquaculture, College of Fisheries, Maharana Pratap University of Agriculture and Technology, Udaipur, Rajasthan, India, for 60 days.

Methodology: One hundred fingerlings of each species were stocked separately in 400-L fibre-reinforced plastic tanks integrated with tomato (Solanum lycopersicum) saplings on floating rafts. Total length and body weight were recorded to establish the length–weight relationship using the power function W = aLᵇ. The coefficient of determination (R²) and regression coefficient (b) were estimated through log-transformed linear regression, and the modified condition factor (K) was calculated from the estimated b value.

Results: A positive length–weight relationship was observed in both species. The coefficient of determination was higher in L. rohita (R² = 0.8554) than in O. mossambicus (R² = 0.7432), indicating a stronger length–weight association in rohu. The b values were 1.9681 and 1.8742, respectively, indicating negative allometric growth in both species. The relationships were statistically significant (p < 0.05). The modified condition factor was higher in L. rohita (2.94) than in O. mossambicus (1.95).

Conclusion: Both species performed satisfactorily under the tested floating-raft aquaponics conditions, with L. rohita showing a stronger length–weight relationship and higher modified condition factor than O. mossambicus. These findings demonstrate the feasibility of rearing both species in floating-raft aquaponics, with rohu exhibiting comparatively better biometric performance.

Spatio-Temporal Assessment of Built-Up Expansion in Ghaziabad District, India Using the Normalized Difference Built-up Index (NDBI)

Sadaf — 2026-09-04

Background: Urbanisation in developing countries has considerably changed land surfaces, including through urban expansion and its effects on natural landscapes.

Aims: The present study investigates the spatial distribution and temporal variation of built-up regions.

Study Design: The Normalized Difference Built-up Index was used to map and quantify the spatial distribution and temporal variation of built-up spaces.

Place and Duration of Study: The NDBI was used to analyse spatio-temporal changes in urban expansion in Ghaziabad district, Uttar Pradesh, India, using multi-temporal Landsat imagery from 2013, 2018, and 2023.

Methodology: The Normalized Difference Built-up Index was used to assess built-up expansion in Ghaziabad district. To create NDBI maps and examine built-up growth trends, the satellite imagery was pre-processed and analysed using geospatial techniques.

Results: The findings show that substantial urbanisation occurred over the study period, especially in the vicinity of the main transport corridors and fast-growing urban and peri-urban centres. Urbanisation was associated with increased infrastructure development and land-use change, leading to declines in open space and cultivated land. The built-up space increased from 639.12 km² in 2013 to 678.70 km² in 2018 and further to 683.96 km² in 2023. Correspondingly, the number of built-up pixels increased from 710,134 in 2013 to 754,106 in 2018 and 759,961 in 2023. The total built-up space increased by 44.84 km² (7.02%) during 2013–2023, with an increase of 39.57 km² (6.19%) between 2013 and 2018 and 5.27 km² (0.78%) between 2018 and 2023.

Conclusion: The results offer important insights into the dynamics and intensity of urban expansion and may inform sustainable urban development, land management, and environmental protection in fast-growing areas.

Growth and Phenological Responses of Rice to Artificial Light at Night

V. P. Karthika — 2026-09-07

An experiment was undertaken at the Regional Agricultural Research Station, Pilicode, to study the effects of artificial light at night (ALAN) on the growth and phenology of rice. The experiment was laid out in a split-plot design, in which the absence and presence of artificial night illumination were considered main-plot treatments and five rice varieties, viz. ‘Rakthashali’, ‘Karuthanjavara’, ‘Chempav’, ‘Uma’ and ‘Jeerakasala’ were used as subplot treatments. Biometric observations were recorded on plant height, tiller number and panicle number. Crop phenological observations, such as duration to booting, heading and maturity, were also noted. The experiment was conducted over two seasons, and in both seasons, the variety ‘Karuthanjavara’ remained in the vegetative stage throughout the experimental period. Although ‘Chempav’ and ‘Jeerakasala’ reached the heading stage, they failed to achieve proper grain filling and did not produce quality seeds. In general, ALAN considerably increased the number of days required to reach the booting stage and extended the total crop duration, while reducing the duration from heading to harvest maturity compared to the non-ALAN-exposed plots. Among the five varieties evaluated, only ‘Rakthashali’ and ‘Uma’ produced harvestable grains under ALAN stress, although their crop duration was longer. ALAN also adversely affected early vegetative growth, resulting in reduced plant height and lower tiller production. One month after transplanting, the mean plant height in the ALAN-exposed main plot was 70.1 cm in autumn and 93.9 cm in summer, compared to 84.7 cm and 98.0 cm in the non-ALAN-exposed main plot. Similarly, the mean number of tillers in the ALAN-exposed plot was 6.4 in autumn and 17.9 in summer, whereas the non-ALAN-exposed plot recorded 15.5 and 28.4 tillers, respectively. In addition, panicle production was lower in the ALAN-exposed plots than in the non-ALAN plots. The ALAN-stressed main plot produced 23.4 panicles in autumn and 17.7 in summer, whereas the non-ALAN-exposed plot recorded 34.4 and 20.7 panicles, respectively. The study revealed that certain rice varieties are sensitive to extended photoperiods and confirmed that the transition from the vegetative to the reproductive phase in rice requires exposure to short-day conditions and relatively longer nights. This research highlights the negative impact of ALAN on rice growth and phenology. Even if improved cultivars tolerate minor night-light stress, extended exposure disrupts flowering schedules, grain filling and total yields in rice-based cropping systems.

Evaluation of the Physicochemical and Microbiological Quality of Borehole Water in the Urban Areas of Muzaffarpur, Bihar, India

Noor Fatma — 2026-09-08

This study evaluated the physicochemical and microbiological quality of borehole water during the post-monsoon period in Mushahari Block, Muzaffarpur, Bihar. Water samples were collected from 15 sites representing slum, residential, and industrial areas and analysed using standard APHA and BIS methods. The assessed parameters included pH, electrical conductivity, total dissolved solids, turbidity, total hardness, alkalinity, major ions, selected trace elements, and total coliforms. The borehole water was neutral to mildly alkaline, with pH values of 7.25–7.61. Total dissolved solids ranged from 466 to 1046 mg/L, while total hardness ranged from 308 to 520 mg/L, indicating substantial mineralisation and hardness. Calcium, magnesium, and alkalinity were also elevated at several sampling locations. Iron and nitrate represented the principal chemical concerns, with mean concentrations of 1.99 mg/L and 71.21 mg/L, respectively, and multiple samples exceeding BIS limits. In contrast, chloride, sulphate, fluoride, arsenic, and manganese remained within the applicable permissible limits. Total coliforms were detected in 6 of the 15 samples, demonstrating localised microbiological contamination. Overall, the observed groundwater quality reflects both geogenic and anthropogenic influences. The findings indicate that treatment, sanitary protection of water sources, improved waste-management practices, and regular monitoring are necessary before the borehole water is considered suitable for safe domestic use.

Assessment of Wetland Functional Responses to Cyperus papyrus Vegetation Biomass Harvesting Using Water Physicochemical Parameters and Macroinvertebrate Diversity in Saf Wetland, Kenya

Robert Juma Ogolla — 2026-09-09

Papyrus (Cyperus papyrus) is the dominant plant species in the floodplain and littoral wetlands of Lake Victoria, where harvesting by riparian communities may affect plant growth and wetland ecosystem functioning. This study evaluated wetland functional responses to papyrus harvesting by integrating surface-water physicochemical parameters with macroinvertebrate diversity metrics. A controlled factorial field experiment compared plots harvested frequently (monthly), moderately (every 2.5 months), and infrequently (every 3.5 months) with adjacent unharvested controls. Water temperature (WT), dissolved oxygen (DO), and electrical conductivity (EC) were measuredin situ, while triplicate samples were collected for total nitrogen (TN), total phosphorus (TP), and macroinvertebrate analyses. Data were analysed using robust two-way ANOVA in R (v4.6.0) because of heterogeneity and unequal sample sizes. Significant spatial variation was detected for EC (F = 12082.6, p = 0.001), WT (F = 31.168, p = 0.001), TN (F = 241.79, p = 0.001), and TP (F = 11.687, p = 0.006). Harvesting treatment did not significantly affect DO, EC, WT, TN, or TP. However, macroinvertebrate diversity was significantly affected by treatment (F = 4.766, p = 0.035), plot (F = 12.184, p = 0.005), and their interaction (F = 12.726, p = 0.004). Saf Wetland therefore maintained relatively stable physicochemical conditions after harvesting, although harvesting intensity influenced nutrient dynamics and macroinvertebrate diversity. Regulated harvesting is important for sustaining wetland ecological integrity and ecosystem-service provision in Lake Victoria papyrus wetlands.

Spatial Accessibility Modelling of Healthcare and Educational Facilities in Ikwerre and Emuoha Local Government Areas, Rivers State, Nigeria

Emeka-Kalu Silver Aku — 2026-09-12

Access to public healthcare and education facilities is a key indicator of improved health status, education, and the socio-economic development of the population. The World Health Organization (WHO) uses the percentage of the population living within 5 km of a primary healthcare facility as an indicator of spatial accessibility. Access to health and education facilities aligns with Sustainable Development Goals 3, 4, and 10. The study focused on modelling the spatial accessibility of public healthcare and educational facilities in Ikwerre and Emuoha LGAs of Rivers State, Nigeria. The study adopted a quantitative research approach to determine the coordinates of public healthcare and educational facilities using a GNSS positioning technique. Secondary data were obtained from Rivers State Ministry of Health, Rivers State Ministry of Education, Universal Basic Education Board, and other relevant agencies. Kernel Density Estimation was used to examine the spatial accessibility of the facilities. Proximity analysis was carried out using a 2 km buffer/radius search. Data were analysed using ArcGIS 10.7 and MS Excel 2019. The study identified 107 public facilities, out of which 82 were educational facilities and 25 were healthcare facilities. Ikwerre LGA had 60 (56%) public facilities while Emuoha had 47 (44%) public facilities. The nearest neighbour analysis of the educational facilities indicated that the facilities were randomly distributed, while KDE analysis identified Elele as the centre of attraction for educational facilities and Ogbakiri as the centre of attraction for healthcare facilities. The proximity analysis indicated that 72 (88%) of the 82 schools and 22 (88%) of the 25 healthcare facilities were located within the 2 km service radius of the communities. The study noted that educational facilities are more accessible than healthcare facilities in the study area. The provision of sufficient healthcare and educational facilities is imperative for improved accessibility.

EDTA-Enhanced Phytoextraction of Cd, Pb, and Cr from Industrially Contaminated Soil by Brassica juncea

Ruby Patel — 2026-09-12

Heavy metal contamination of industrial soils is a persistent environmental concern because of the toxicity and non-biodegradable nature of cadmium (Cd), lead (Pb), and chromium (Cr). This study evaluated EDTA-assisted phytoremediation using Brassica juncea in contaminated soils collected from the Bhiwandi industrial region, Maharashtra, India. Soil samples were characterised for physicochemical properties and metal concentrations, and B. juncea was cultivated under greenhouse conditions. A 0.1 M EDTA treatment was applied to enhance metal availability. Metal uptake was quantified by atomic absorption spectrophotometry, while chlorophyll content, antioxidant enzyme activities, bioaccumulation factor (BAF), translocation factor (TF), and removal efficiency were assessed. EDTA treatment increased the uptake and translocation of Cd, Pb, and Cr. BAF values ranged from 2.41 to 5.81, while removal efficiencies were 48.6% for Cd, 62.9% for Pb, and 40.7% for Cr. Heavy metal exposure was associated with reduced chlorophyll content and increased superoxide dismutase and catalase activities, indicating activation of antioxidant defence responses. The findings indicate that EDTA can enhance the phytoextraction performance of B. juncea under the conditions examined. However, the environmental persistence of EDTA and the potential mobility of metal–chelate complexes require careful consideration. Evaluation of biodegradable chelating agents under field conditions is therefore warranted before broader application of this approach.

Assessing the Level of Awareness of Solid Waste Management in Sampou Community

Herbert O. Stanley — 2026-09-15

The rapid growth of solid waste and its improper management pose severe health, environmental, and economic risks, especially in rural Nigerian communities such as Sampou, where data on public awareness and practices are lacking. This study aimed to assess the level of awareness of solid waste management (SWM) methods and their environmental impacts among Sampou residents, examine the influence of demographic factors on this awareness, and identify barriers to adopting proper waste-management practices. This descriptive cross-sectional study was carried out in Sampou Community, Kolokuma/Opokuma Local Government Area, Bayelsa State, Nigeria, between April 2024 and June 2025. A total of 382 household heads or their representatives were selected through systematic random sampling and surveyed using an interviewer-administered, semi-structured questionnaire. Data were analysed using SPSS Version 30.0, with descriptive statistics and chi-square tests. The results revealed that only 44% of respondents had heard of SWM, with 34.8% showing good awareness, 60.5% fair awareness, and 4.7% poor awareness. Disposal practices were dominated by dumping in water bodies (70.4%) and open spaces (27.2%), while 72.8% were aware of the dangers of improper SWM. Education (p = 0.0048) and income level (p < 0.001) were significantly associated with awareness. Key barriers included the absence of proper dumpsites (23.8%), lack of waste bins (16.8%), and inadequate knowledge (13.1%). Awareness and proper waste-management practices remain low despite high perceived risk, with education and income influencing awareness levels. However, where proper infrastructure is absent, appropriate waste-management methods cannot be practised, irrespective of awareness. To improve outcomes, the study recommends implementing community-based SWM education programmes, providing affordable waste bins and accessible disposal facilities, enforcing regulations on waste practices, and increasing government-community partnerships to promote sustainable waste management in Sampou.

Relationship between Diatoms and Zooplankton Distribution in Lake Dogodogo Located in Bujumbura Province, Burundi

Simon Buhungu — 2026-09-16

Lake Dogodogo supports diverse plankton communities that contribute to aquatic food-web processes. This study assessed the influence of planktonic diatoms on zooplankton distribution to inform sustainable management of the lake’s fishery resources. Sampling was conducted twice monthly from May to August 2022 at seven stations representing littoral and pelagic conditions. Zooplankton and diatoms were collected with a 50 µm plankton net by five successive immersions per station to form a composite sample, which was fixed with 5% formalin. Species were identified microscopically, abundances were determined, diversity indices were calculated, and differences among stations were evaluated using ANOVA. Redundancy analysis was used to examine relationships between diatoms and zooplankton. In total, 33 zooplankton species belonging to rotifers, copepods and cladocerans and 17 diatom species were recorded. Polyarthra vulgaris was the most abundant zooplankton species, whereas Epithemia cistula was dominant among diatoms. Several zooplankton taxa varied significantly among stations, while planktonic diatoms did not show significant spatial variation. Zooplankton was generally more diverse and abundant than diatoms. Redundancy analysis indicated that Gomphonema parvulum and Gomphonema truncatum significantly influenced zooplankton distribution. The observed decline in diatom abundance during periods of greater zooplankton abundance was consistent with grazing pressure. These findings show that Lake Dogodogo contains substantial plankton biodiversity and that diatom–zooplankton relationships are relevant to understanding its ecological functioning and conservation.

Socio-institutional and Policy Constraints Associated with Planned Grazing Adoption in Naibunga Community Conservancy, Laikipia County, Kenya

Donar Kwatukha Nalwere — 2026-09-16

Aims: This study aimed to examine the socio-institutional and policy-related constraints influencing adoption and long-term implementation of planned grazing within communally governed group ranches.

Study Design: The study adopted a mixed-methods embedded design in which qualitative data from key informant interviews were integrated with quantitative data from household surveys and ecological field measurements.

Place and Duration of Study: The study was conducted in Naibunga Conservancy located in Laikipia County, Kenya. This conservancy comprises nine group ranches. The study was conducted for a period of six months.

Methodology: Data were collected from 210 household heads drawn from six group ranches through structured survey questionnaires, supplemented by interviews with six key informants comprising group ranch chairpersons from adopting and non-adopting ranches. Quantitative data were analysed using descriptive statistics, chi-square tests with Cramér’s V, Cronbach’s alpha, and binary logistic regression, while qualitative data were analysed thematically.

Results: Group-ranch implementation status was significantly associated with adoption (OR = 10.17, 95% CI [4.98, 20.74], p < 0.001). A livestock-based livelihood (OR = 4.74, 95% CI [1.10, 20.35], p = 0.036) and cattle holding (OR = 1.44, 95% CI [1.00, 2.06], p = 0.048) were also significantly associated with adoption. Lack of awareness and education at the group-ranch level was the most frequently endorsed constraint, reported by 92.7% of respondents. Insufficient funding, inadequate infrastructure, inadequate technical support services and perceived input costs each received more than 80% endorsement. Ineffective policy implementation was the least frequently endorsed constraint, at 69.5%.

Conclusion: The findings indicate that constraints on the adoption of community-based grazing interventions are concentrated in group-ranch institutions and support services rather than in individual reluctance. Strengthening these institutions, securing sustainable financing and investing in supporting infrastructure are important if CBNRM approaches are to advance their social and ecological objectives in Kenya’s pastoral drylands.

Contribution to the Implementation of Ambient Gamma Radiation Mapping Using the PGIS-2 Detector in Abidjan, Côte d’Ivoire

Agba Dabo Salif Ignace — 2026-09-16

Background: Environmental radioactivity monitoring is important for assessing ambient gamma-radiation exposure and establishing local radiological baseline information. In Côte d’Ivoire, ambient gamma radiation has previously been measured using other techniques; however, the use of the PGIS-2 detector combined with Surfer-based spatial mapping has not been reported. This study therefore explores this approach for generating spatially resolved ambient gamma-radiation information in Abidjan.

Aims: This work contributes to the implementation of ambient gamma radiation mapping through familiarization with the PGIS-2 detector and Surfer software, with a view to using them to map this radiation in Côte d’Ivoire.

Place and Duration of Study: The study was conducted at “University Felix Houphouët Boigny” in Abidjan over a period of one week.

Methodology: The PGIS-2 detector was carried in a backpack worn by the experimenter. The latter moved across the study site at a pace of one step per second, that is, at a speed of less than 4 km/h, while the detector recorded the dose rate at one-second intervals, as well as the geographic coordinates (latitude and longitude) of each measurement point.

Five-minute measurements in a fixed position, with the detector placed 1 m above the ground, were carried out at three different locations. The data obtained served as normalization values for the other measurements performed more than one meter above the ground. Mapping of ambient gamma radiation was carried out using Surfer software to analyze the PGIS-2 data.

Results: The ambient gamma effective dose rates obtained ranged from (16 ± 4) nSv/h to (244 ± 16) nSv/h, with an average of (50 ± 7) nSv/h. The corresponding annual effective dose based on this average was (0.09 ± 0.01) mSv. From these data, a histogram was plotted and an isodose map was produced.

Conclusion: The average ambient gamma effective dose rate obtained at the measurement site was slightly above the global average ambient gamma radiation dose in outdoor air provided by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). However, the corresponding annual effective dose was well below the global ambient gamma radiation dose limit for the public recommended by the International Commission on Radiological Protection (ICRP).

The plotted histogram showed two sets of minimum and maximum dose values corresponding to the light and dark areas on the isodose map.

Soil Texture as a Determinant of Groundwater Recharge Potential in Semi-arid Hard Rock Terrain of Yadgir District, Karnataka, India

Pavankumar Deshetty — 2026-09-17

Aims: To determine whether the spatial distribution of soil textural classes across the Yadgir and Gurmitkal blocks can predict groundwater recharge conditions observed at borewell sites, using an infiltration-capacity-based suitability ranking.

Study Design: Spatial soil-texture mapping combined with a five-tier recharge suitability ranking, cross-validated against field-observed borewell hydrogeological parameters.

Place and Duration of Study: Yadgir and Gurmitkal blocks, Yadgir District, Karnataka, India, covering 1,711.6 sq. km and 45 target villages; geohydrological data collected under the Kalike programme, with rainfall records spanning 1995–2024.

Methodology: Soil texture governs infiltration rate, water-holding capacity, and porosity. These three properties directly control the volume of rainwater reaching the saturated zone in hard rock aquifers. Despite its recognised importance, soil texture has seldom been isolated as the sole explanatory variable in groundwater recharge potential assessments for the crystalline basement terrain of the Deccan Plateau. This study examines the spatial distribution of twelve soil textural classes across 1,711.6 square kilometres of the Yadgir and Gurmitkal blocks in the Yadgir District of Karnataka, India. It uses National Bureau of Soil Survey and Land Use Planning maps refined with IRS Resource SAT 2 LISS IV 5.8 m imagery.

Results: Mapped soil classes range from clay (167.65 sq. km) to clay loam (405.57 sq. km). Loamy sand is the most extensive class, covering 460.26 sq. km (26.9%). Sandy loam covers 327.31 square kilometres, and sand spans 75.85 sq. km. Minor occurrences include gravelly sand at 1.16 square kilometres and gravelly sandy loam at 8.38 square kilometres. A textural-class-based recharge suitability ranking is applied to the area. This ranking is grounded in published infiltration capacity hierarchies for Indian semi-arid soils. It is also cross-validated against hydrogeological observations from 247 borewells. Villages underlain by loamy sand and sandy loam show shallower first water strike depths at 30 to 60 feet below ground level. Their static water levels range from 11 to 40 feet below ground level. In contrast, clay-dominated areas have first water strikes and static water levels deeper than 60 feet below ground level. This confirms the field-level correspondence between coarser-textured soils and better recharge conditions. These findings have direct implications for prioritising artificial recharge structures and borewell siting in the selected intervention villages.

Conclusion: Soil texture, mapped at NBSS and LUP resolution and ranked by infiltration capacity, is a reliable, low-cost predictor of groundwater recharge potential in hard-rock, semi-arid terrain and can directly guide managed aquifer recharge structure siting.

Evaluation of Antagonist Effect of Trichoderma species against Vascular Wilt Causing Fusarium solani on Solanum melongena

Rajni Sen — 2026-09-17

Brinjal (Solanum melongena L.) is an economically important vegetable crop that is susceptible to a range of soil-borne fungal diseases, including vascular wilt caused by Fusarium solani. The present study investigated the in vitro antagonistic potential of Trichoderma isolates against F. solani and assessed their relative efficacy in suppressing the mycelial growth of the pathogen. Ten Trichoderma isolates were recovered from rhizospheric soil associated with healthy brinjal plants collected from different locations across the Bundelkhand region. The isolates were maintained in pure culture and assessed against F. solani using a dual-culture assay on potato dextrose agar. Mycelial discs of the pathogen and each antagonist were placed on opposite sides of Petri plates, which were incubated at 26°C for 9 days. Pathogen growth was assessed on the third, sixth, and ninth days, and percentage inhibition was determined relative to the control. All ten Trichoderma isolates exhibited antagonistic activity against F. solani, with differences in inhibitory performance among isolates. TCX5, identified as Trichoderma harzianum, showed the highest antagonistic activity, whereas TCX3 showed the lowest inhibition among the tested isolates. These findings demonstrate isolate-level variation in the antagonistic potential of Trichoderma against F. solani under laboratory conditions. The promising isolates require further molecular characterisation and validation under greenhouse and field conditions before their practical use in brinjal wilt management can be recommended.

A Composite Irrigation Water Quality Index and Leaching Requirement for Groundwater of Durg Block, Chhattisgarh, India

Kapil Verma — 2026-09-17

Irrigation water quality is conventionally reported as a set of separate indices: electrical conductivity, sodium adsorption ratio, soluble sodium percentage, residual sodium carbonate, Kelly's index, permeability index and magnesium adsorption ratio, each classified against its own limit. A water that is acceptable on every index taken singly may nevertheless be close to several limits at once, and that condition is invisible to the index-by-index reading. This study combines the seven indices into a single composite irrigation water quality index and converts the measured salinity into the extra water needed to keep the root zone below a target salinity, for ten observation wells in Durg block, Chhattisgarh. The composite index ranged from 11.8 to 58.3, placing seven wells in the no-restriction class, two in low restriction and one, Maroda, in moderate restriction. Maroda is not the most saline well in the block; its electrical conductivity of 0.79 dS m⁻¹ is below the block mean, and it passes every index individually, yet it stands simultaneously at 76, 83, 91 and 88 % of the permissible limits for soluble sodium percentage, Kelly's index, permeability index and magnesium adsorption ratio, and is the only well with a positive residual sodium carbonate. It is the sodicity profile rather than the salinity that sets it apart, and only the composite treatment brings that out. The leaching requirement, computed from the salinity of each well, ranged from 3.8 to 11.9 % of the applied water for a target soil salinity of 3 dS m⁻¹, the threshold for paddy, and from 1.9 to 5.6 % for 6 dS m⁻¹, the threshold for wheat, so a leaching fraction of about one-eighth of the applied depth is sufficient across the block for its principal crops. The two most saline wells, Durg and Anda, require the largest leaching fractions and are also those where a shift towards more salt-tolerant crops would be most economical.

Assessment of Faunal Biodiversity and Its Ecological Role in the Yamuna River, Delhi NCR, India

Parkash Singh — 2026-09-18

The Yamuna River is an ecologically important freshwater system that is increasingly affected by urbanisation, sewage discharge, industrial effluents, and other anthropogenic pressures. Such disturbances can alter water quality and adversely affect aquatic communities. Because fish, zooplankton, macroinvertebrates, and benthic fauna respond to changes in environmental conditions, their diversity and distribution can provide useful indications of river ecosystem health. The present study was conducted to comparatively assess faunal diversity, water quality, and anthropogenic disturbance at three selected sites along the Yamuna River: Palla Ghat, Jhangola Ghat, and Kashmiri Gate Ghat. The findings revealed considerable spatial variation in aquatic faunal diversity and environmental conditions among the study sites. Palla Ghat recorded high faunal diversity, good water quality, and low anthropogenic disturbance, indicating relatively favourable conditions for aquatic organisms. The fish community included Labeo rohita (Rohu), Catla catla (Catla), Cirrhinus mrigala (Mrigal), Channa spp., and Clarias spp. The zooplankton community comprised rotifers, cladocerans, and copepods, while macroinvertebrates and benthic fauna included oligochaetes, chironomid larvae, molluscs, and other aquatic invertebrates. Jhangola Ghat exhibited moderate faunal diversity, moderate water quality, and moderate anthropogenic disturbance. Its fish assemblage was represented mainly by Labeo rohita, Catla catla, and Cirrhinus mrigala, along with rotifers, cladocerans, copepods, annelids, molluscs, insect larvae, and other benthic organisms. In contrast, Kashmiri Gate Ghat showed low faunal diversity, poor water quality, and high anthropogenic disturbance. The fish community was comparatively limited, with Labeo rohita and Catla catla recorded, while the zooplankton community was dominated by cladocerans and copepods, and the benthic community consisted mainly of insect larvae and other benthic organisms. Overall, the study demonstrates a clear association between water quality, anthropogenic pressure, and aquatic faunal diversity.

Seasonal Abundance, Spatial Distribution, and Environmental Determinants of African Trypanosome Vectors in Two Protected Areas of Southwestern Nigeria

S. A. Abioye — 2026-09-24

Aims: This study investigated the seasonal abundance, spatial distribution, and environmental determinants of African trypanosome vectors (ATVs) in Omo Biosphere Reserve (OBR) and Oba Hills National Park (OHNP), southwestern Nigeria.

Study Design: The study was conducted from November 2023 to August 2025 across dominant vegetation types in OHNP and OBR. In OHNP, sampling sites comprised secondary forest, savannah woodland, and riparian forest, while OBR sites included primary forest, secondary forest, and riparian forest.

Methodology: Entomological surveys were conducted across major vegetation types using 24 Nzi traps set along a 1-km transect during wet (May–October) and dry (November–April) seasons. Relative humidity, altitude, temperature, and precipitation were recorded, and their associations with vector abundance were assessed using regression analyses.

Results: Of 3,589 biting flies collected, 732 (20.4%) were ATVs, comprising three families, seven genera, and 15 species. OBR accounted for 57.9% of ATVs and OHNP 42.1%. Vector abundance was significantly higher during the dry season, with wet-season abundance reduced by 47.4% (β = 0.53, p < 0.001). Glossina spp. comprised 44.8% of ATVs, with 81.1% occurring in OBR. Relative humidity was negatively associated with vector abundance (β = 0.97, p = 0.004), whereas altitude showed a positive association (β = 1.01, p = 0.004).

Conclusion: Abundance was highest in riparian forests of OBR and savannah woodland of OHNP. These findings highlight the importance of habitat-specific surveillance and integrated vector management for protecting biodiversity, wildlife health, and public health in protected ecosystems.

Spatial Distribution, Environmental Associations and Geographical Mapping of Microscopy-confirmed Malaria Cases among Children under Five in Nigeria

Charles Olalekan Collins — 2026-09-29

Aims: This study assessed the prevalence and geographical distribution of microscopy-confirmed malaria among children aged 6–59 months in Nigeria, examined selected environmental associations and spatial clustering, modelled cluster-level malaria probability, and identified geographical areas with comparatively higher model-predicted probabilities.

Study Design: Cross-sectional secondary analysis of nationally representative survey data integrated with environmental and geospatial datasets.

Place and Duration of Study: Nigeria; analysis used data from the 2021 Nigeria Malaria Indicator Survey and environmental datasets corresponding to the survey period.

Methodology: Data for 10,655 children from 567 survey clusters were analysed using survey-weighted prevalence estimation and complex-samples logistic regression. Cluster locations were linked with environmental data, and Local Moran’s I was used to identify statistically significant spatial clusters and outliers. Model-predicted probabilities were aggregated to cluster level and used to identify intervention-priority areas.

Results: National malaria prevalence was 22.3%, ranging from 2.6% in Lagos to 49.2% in Kebbi. Prevalence was higher in rural than urban areas (26.7% versus 10.5%; P < .001). Annual rainfall was associated with malaria in one alternative model, while elevation and built-up land coverage showed inverse associations. Local Moran’s I identified 193 significant clusters and outliers, including 45 High–High hotspots and 107 Low–Low coldspots. Model-predicted probabilities of malaria across the survey clusters ranged from 1.7% to 37.3%; 272 of 567 clusters (48.0%) were classified as higher categories of model-predicted probability. Bauchi and Jigawa had the highest intervention-priority percentages (87.5% each), followed by Ebonyi (84.6%), Katsina (82.4%) and Kebbi (80.0%).

Conclusion: Childhood malaria risk in Nigeria shows marked geographical variation. The identified hotspots and priority areas can support population-level surveillance, resource allocation and targeted malaria control. Given the model’s modest predictive performance and displacement of DHS cluster coordinates, the estimates should not be interpreted as individual-level clinical predictions.

Assessment of Heavy Metals in a Rural River Receiving Agricultural Effluents: Ecological Health Implications

L. A. Osagiede — 2026-09-30

Heavy metal contamination of freshwater ecosystems poses significant risks to aquatic organisms, human health and the sustainability of freshwater resources. This study assessed the concentrations, spatial variation, pollution status and potential ecological risks associated with selected heavy metals in the lower section of River Adofi, Delta State, Nigeria. Water samples were collected monthly from three sampling stations over nine months, from September 2025 to May 2026. Samples were analysed for copper (Cu), lead (Pb), silver (Ag), zinc (Zn) and cadmium (Cd) using atomic absorption spectrophotometry. Descriptive statistics, one-way analysis of variance, principal component analysis and hierarchical cluster analysis were employed to evaluate spatial patterns and relationships among the metals. Heavy Metal Pollution Index (HPI), Contamination Factor (CF), Pollution Load Index (PLI), ecological risk factor (Er) and Potential Ecological Risk Index (PERI) were used to assess pollution and ecological risk. Mean concentrations of Cu, Pb, Ag, Zn and Cd ranged from 0.5611–0.7533, 0.0299–0.0788, 0.4600–0.5867, 1.2167–1.6280 and 5.8633–6.0778 mg/L, respectively. Significant spatial differences were recorded for Pb (p = 6.2 × 10⁻⁶) and Zn (p = 0.00022), whereas Cu, Ag and Cd showed no significant differences among stations. The PLI values were 6.81, 5.36 and 5.65 for Stations 1, 2 and 3, respectively, indicating a substantial overall pollution load. HPI values were also extremely high at all stations, exceeding the critical value of 100. Cadmium exhibited exceptionally high contamination factors and was the principal contributor to the ecological risk, while Cu, Zn and Pb generally presented low individual ecological-risk values. The PERI values were 59,619.81, 58,650.23 and 60,800.87 for Stations 1, 2 and 3, respectively, indicating very high potential ecological risk. The findings demonstrate substantial heavy metal contamination of River Adofi, particularly from Cd, with implications for aquatic ecosystem integrity and human use of the river. Regular monitoring, pollution-source control and appropriate remediation measures are therefore required to protect the ecological functions and beneficial uses of the river.

Pharmaceutical Contaminants in Aquatic Environments: A Critical Synthesis of Sources, Ecological Risks and Bioremediation Strategies

Yogita Basene — 2026-08-28

Pharmaceutical residues are now routinely detected in wastewater-impacted aquatic environments because medicinal compounds and their metabolites enter sewerage, industrial effluents, agricultural drainage and receiving waters through multiple, often continuous pathways. Their environmental significance cannot be inferred from occurrence alone: risk depends on potency, exposure duration, mixtures, transformation products, species sensitivity and the capacity of treatment systems to reduce biologically active mass. This critical narrative review integrates evidence on sources, ecological effects and bioremediation, with emphasis on wastewater-impacted freshwaters and on technologies that rely substantially on microbial, fungal, algal or plant-associated processes. Literature was selected through live searches of multidisciplinary and environmental or biomedical scholarly sources, supplemented by citation searching and DOI verification. The strongest causal ecological evidence comes from whole-ecosystem work with endocrine-active pharmaceuticals, while laboratory and field studies also support concern for behavioural disruption, chronic sublethal effects and antibiotic-driven selection for antimicrobial resistance. Nevertheless, extrapolation remains difficult because monitoring is dominated by parent compounds and targeted analytes, whereas mixtures and transformation products are incompletely characterised. Conventional activated sludge provides variable and compound-specific attenuation; apparent parent removal may reflect sorption or transformation rather than mineralisation. Membrane bioreactors, adapted bacterial consortia, white-rot fungi, microalgae and constructed wetlands can improve removal under favourable conditions, but evidence is uneven across scales and frequently relies on high test concentrations or parent disappearance. The synthesis indicates that no single biological technology provides universal control. Risk reduction is more defensibly pursued through source control, robust biological treatment and targeted polishing, supported by mass balances, transformation-product screening, effect-based endpoints and antimicrobial-resistance assessment. Future research should prioritise trace-level, full-scale comparisons and standardised demonstrations that connect chemical removal to reduced biological hazard.

New Additions to the Flora of Orissa: An Updated Checklist on New Distributional Records of Plant Species to the State of Odisha from 1996 Onwards- A Literature Synthesis

Nabin Kishore Jena — 2026-09-10

Among the eastern Indian states, Odisha plays a vital role in the study of floristic diversity due to its unique geographical location, variation in geological factors, and diversity in floristic composition. The monumental work of H. O. Saxena & M. Brahmam during 1994-1996 documented a total of 2,727 species in the Flora of Orissa. In the present review, an attempt has been made to prepare a database of new distributional records of plant species in the flora of Odisha from 1996 onwards. To compile a comprehensive account of new distributional records, literature from the last 30 years (1996-2025) was searched in databases such as Google Scholar, ResearchGate, Wiley Online Library, JSTOR, Scopus, and Springer Nature using keywords such as “new additions to the flora of Odisha”, “new distributional record to Odisha flora”, “new records to the flora of Odisha”, “new records to Eastern Ghats”, and “note on the identity”. In addition, herbarium consultations were conducted at CSIR-IMMT, Bhubaneswar, RPRC-Bhubaneswar, and CNH-Kolkata. A total of 176 papers were accessed, of which 165 provided information on new distributional records of 222 plant species belonging to 71 families during the last three decades; consequently, the documented plant species composition has been updated to 2,949. Among the recorded plants, angiosperms were dominant, with 209 species (147 dicotyledons and 62 monocotyledons), followed by 11 pteridophytes in 5 families and 2 gymnosperms in 1 family. The authors of these studies deposited herbarium specimens in the herbaria of CNH, RPRC-Bhubaneswar, Utkal University, MSCB University, Berhampur University, RRL-B, CSIR-NBRI, and NBPGR. This literature synthesis serves as reference material for policymakers and conservation biologists regarding habitat protection and species conservation.

Air Pollution and Human Health: A Comprehensive Narrative Review

Najmaldin Ezaldin Hassan — 2026-09-17

Air pollution is a major environmental and public-health concern associated with substantial adverse effects on human health and ecosystems. This narrative review synthesises evidence concerning the principal sources and categories of air pollutants, their reported health effects, vulnerable populations, geographical patterns, and available mitigation approaches. Major pollutants considered include particulate matter (PM₂.₅ and PM₁₀), nitrogen oxides, sulphur dioxide, ozone, carbon monoxide, and volatile organic compounds originating from transport, industrial activities, fuel combustion, household sources, and natural events. The reviewed evidence indicates associations between exposure to these pollutants and respiratory disorders, cardiovascular disease, neurological effects, cancer, and adverse reproductive and developmental outcomes. Children, older adults, pregnant women, individuals with pre-existing illnesses, and socioeconomically disadvantaged populations may experience greater exposure or susceptibility. Air-pollution patterns and associated health burdens vary geographically according to industrialisation, urbanisation, emission sources, regulatory frameworks, and socioeconomic conditions. The review further considers policy interventions, cleaner fuels, urban planning, catalytic converters, industrial emission-control technologies, indoor air purification, public education, and community participation as approaches to pollution mitigation. Persistent challenges include uncertainties regarding long-term low-level exposure, emerging contaminants, unequal exposure, economic constraints, and implementation barriers. Overall, coordinated regulatory, technological, monitoring, research, and community-level approaches are required to reduce pollutant exposure and support effective air-quality management.

A Critical Review of Microplastic Contamination in Agricultural Soils and its Potential Risks to Crops and Human Health

Ranjan Kumar — 2026-09-28

Microplastic contamination of agricultural soils has moved from a largely conceptual concern to an empirically documented component of terrestrial pollution. Agricultural plastic films, sewage sludge, compost and other organic amendments, irrigation water, atmospheric deposition, and diffuse litter can introduce plastic particles to soil, while tillage, weathering, bioturbation, and water movement redistribute and fragment them. This critical narrative review evaluates evidence on the occurrence and persistence of microplastics in agricultural soils, consequences for soil function and biota, uptake and toxicity in crops, transfer to edible tissues, and implications for human health. Literature published from 1 January 2012 to 17 July 2026 was identified through multidisciplinary and agriculture-, environmental-, and health-oriented scholarly sources and appraised for analytical validity, environmental realism, study design, and claim-source alignment. Field studies provide convincing evidence that repeated plastic mulching and sludge application can increase soil contamination, but cross-study abundance estimates remain poorly comparable because particle-size windows, extraction efficiencies, polymer identification, and reporting units differ. Controlled experiments show that microplastics can alter aggregation, porosity, water relations, microbial activity, soil fauna, plant growth, nutrient acquisition, photosynthesis, and oxidative balance; nevertheless, effect direction depends strongly on polymer, shape, size, concentration, soil, and crop. Evidence for true plant internalisation is strongest for nanoplastics and submicrometre particles, especially in controlled systems, whereas field-scale transfer of larger microplastics into edible tissues remains uncertain. Human biomonitoring demonstrates exposure to plastic particles through multiple routes, and emerging observational data raise legitimate health concerns, but no study has established a causal pathway from contaminated agricultural soil through crops to a defined human disease outcome. The most defensible risk interpretation is therefore pathway-specific: agricultural soil contamination is established, crop effects are plausible and increasingly supported, food-chain transfer is demonstrated under selected conditions, and human health risk from the soil-crop route remains insufficiently quantified. Progress depends on harmonised analytical methods, realistic field exposures, quantitative crop-transfer studies, and route-resolved human exposure assessment.

Methylmercury in Water Bodies Adjacent to Coal-fired Thermal Power Plants: A Global Critical Review of Pathways, Evidence and Uncertainties

Ruchita Salilmoy Haldar — 2026-09-30

Coal-fired thermal power plants remain one of the largest anthropogenic sources of mercury, yet the extent to which they raise methylmercury, the bioaccumulative and neurotoxic form, in nearby lakes, reservoirs, rivers, wetlands and coastal waters is contested. Atmospheric deposition, ash disposal, flue-gas desulphurisation wastewater and seawater desulphurisation discharges each deliver mercury to receiving waters, but methylmercury is formed in situ by anaerobic microorganisms, and its concentration in biota depends on local biogeochemistry and food-web structure as much as on inorganic mercury loading. This critical narrative review synthesises peer-reviewed field, experimental, isotopic and modelling evidence, together with authoritative institutional sources, published from 1990 to July 2026, to evaluate whether proximity to coal-fired plants predicts methylmercury in adjacent water bodies across North America, Europe, Australia, southern Africa, South Asia, East Asia and South America. Literature was identified through multidisciplinary scholarly indexes and citation searching and was appraised for design, analytical adequacy, source attribution and representativeness. The evidence is strongest for near-field enrichment of inorganic mercury in precipitation, soils and dated lake sediments, supported by stable-isotope fingerprints and historical sediment records that track plant commissioning and retrofitting. Evidence that such enrichment translates into higher methylmercury in water and fish is inconsistent. Several studies report no distance gradient or even lower fish mercury near plants, a pattern plausibly explained by plume reduction of oxidised mercury, co-emitted selenium, sulphur-mediated effects on methylation and ecosystem-specific methylation potential. Ash spills and ash-amended sediments can stimulate methylation, whereas outcomes of regulated wastewater and seawater desulphurisation discharges are site-dependent. Major gaps include the scarcity of methylmercury measurements in waters near plants in India, South-East Asia and much of Africa, the dominance of total mercury rather than methylmercury as the reported endpoint, and few before-and-after designs around plant retirement or pollution-control retrofitting. Source-resolved monitoring that pairs compound-specific isotopes with methylation rate measurements and food-web indicators is needed to determine where plant-level controls will most reduce exposure. The review concludes that coal-fired plants are a well-established regional and global driver of aquatic methylmercury, but that their local signature is conditional and cannot be assumed from proximity alone.