DSpace Community:

A Systematic Review of Emerging Contaminants in Surface Waters

2025-11-08T08:28:49Z

Title: A Systematic Review of Emerging Contaminants in Surface Waters Authors: Saheedha, N. Abstract: Emerging contaminants (ECs) such as pharmaceuticals, personal care products, endocrine disrupting chemicals (EDCs), microplastics, and industrial additives are increasingly being discovered in surface waters globally. These unregulated and persistent pollutants originate from diverse sources including urban wastewater, agricultural runoff, and industrial effluents. Even though there have been extensive studies on ECs in marine and soil matrices, their presence, migration, and monitoring in surface freshwater systems remain a growing concern. The aim of this systematic review is to identify the major sources and types of ECs in surface waters, summarize their ecological and health impacts on humans, and assess conventional and emerging methods for monitoring ECs. The PRISMA guideline was used to ease the review process. Fourty peer-reviewed papers between 2010 and 2024 were examined, selected from Scopus, ScienceDirect, SpringerLink and Wiley Online Library databases using keywords including "emerging contaminants," "surface water," "monitoring techniques," "ecological impacts," and "wastewater pollution." The findings highlight wastewater outfalls, agricultural pesticides, and industrial effluents as dominant sources. ECs enter water bodies via runoff, leaching, sewer overflow, and atmospheric deposition. ECs pose grave health issues such as hormonal interference, reproductive disorders, and antibiotic resistance in human beings, as well as endocrine dysfunction and death in aquatic organisms. Classical methods such as gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC-MS/MS) are precise and costly and require a lot of time. New technologies such as biosensors and remote sensing approaches using UAVs are being developed as potential alternatives for bulk, real-time surveillance. EC pollution control requires a multi-dimensional approach, including regulation, technological advancement, and awareness among the public. This review necessitates the construction of sustainable water monitoring systems to ensure the integrity of aquatic ecosystems and human health.

Impact of Different Cover Crop Management Systems on Soil Properties

2025-11-08T08:27:29Z

Title: Impact of Different Cover Crop Management Systems on Soil Properties Authors: Prabha, H.A.V.R.; Indumini, U.K.A.; Hettiarachchi, R.P.; Liyanaarachchi, L.A.T.S.; Jayaneththi, U.; Nayanarangani, M.D.P. Abstract: Rubber (Hevea brasiliensis) is a vital plantation crop in Sri Lanka, contributing significantly to the agricultural sector. However, continuous rubber cultivation causes a decline in soil fertility, negatively impacting long-term productivity. The study aimed to characterize the soil chemical properties in immature rubber lands under different cover crop management practices. Eighteen soil samples were collected from 0 - 0.15 m depths in three different immature rubber lands (Blocks) situated within the Boralu soil series at Clyde estate. Each site represented a different cover crop condition (treatment): Fully Established Cover Crop, 12 months (FCC), Partially Established Cover Crop, 6 months (PCC), and Natural Vegetation Cover (NVC). Mucuna bracteata was utilized as a cover crop, and a consistent fertilizer application was employed across all sites. The collected soil samples were analyzed for key chemical properties, including soil pH, soil organic carbon (SOC), exchangeable potassium (Ex. K), exchangeable magnesium (Ex. Mg), total nitrogen (TN), and available phosphorus (Av. P). The study employed a Randomized Completely Block Design (RCBD), with data analyzed using analysis of variance (ANOVA) followed by mean separation using the Least Significant Difference (LSD) test. The experimental setup included three treatments (FCC, PCC, and NVC), with three sites considered as blocks. The results indicated that SOC (1.3 ± 0.09%), Av. P (20.17 ± 0.19 mg kg-1), Ex. K (59.3 mg kg-1), and Ex. Mg (24.25 ± 8.28 mg kg-1) was significantly highest under FCC, while TN (2.4 ± 0.19 mg kg-1) was highest under NVC. All measured soil chemical parameters exceeded the existing soil nutrient conditions in the Boralu soil, SOC (0.9–1.3%), Av. P (20–35 mg kg-1), Ex. K (40–60 mg kg-1), Ex. Mg (20–30 mg kg-1), and TN (0.09–0.13%). However, soil pH did not significantly differ among the three cover crop management practices. Overall, the FCC significantly improved most soil chemical parameters, except TN. These findings emphasize the potential benefits of cover crop management in enhancing soil chemical properties in immature rubber plantations in Sri Lanka.

Impact of Heating Temperature on Water Repellency and Functional Group Alterations of Leaf Litter Ash from Japanese Cedar (Cryptomeria japonica) and Japanese Cypress (Chamaecyparis obtusa)

2025-11-08T08:25:05Z

Title: Impact of Heating Temperature on Water Repellency and Functional Group Alterations of Leaf Litter Ash from Japanese Cedar (Cryptomeria japonica) and Japanese Cypress (Chamaecyparis obtusa) Authors: Rajapaksha, R.A.N.D.; Leelamanie, D. A.L.; Mori, Y.; Liyanage, T.D.P. Abstract: Water repellency (WR) is a phenomenon where soil resists wetting due to the presence of organic matter (OM). Compositional and structural changes in this OM can alter the degree of WR, subsequently affecting the bio physicochemical properties of soils. Forest fires can transform biomass into ash with varying hydrophobicity levels, which in turn affect the soil hydrology by reducing water infiltration and disrupting moisture distribution. However, limited information exists on how temperature variations affect WR and functional groups of litter ash during heating. This study investigated the temperature influences on WR and functional groups in leaf litter ash of Japanese cedar (CED) and Japanese cypress (CYP). The litter of these two coniferous species are rich in hydrophobic resins and waxes to induce WR and are susceptible to wildfires. Leaf litter was heated at 100, 200, 300, 400, 500, and 600 °C for 20 min in a muffle furnace, with a control sample at 28 °C. The degree of WR (contact angle; θ) and functional group changes were measured with the molarity of ethanol droplet test and Fourier transform infrared spectroscopy (FTIR), respectively. The control samples of both species were highly water-repellent (θ = 125° and 119°) for CED and CYP, respectively. Litter WR decreased with increasing temperature to become wettable at 600 °C (θ = 90°). In FTIR analysis, three absorbance peaks of B, C, and E were recorded (wavenumbers = 3020–2800 cm–1, 1640–1600 cm–1, 1170–950 cm–1, respectively), which consist of hydrophobic functional groups causing ash WR. These peaks disappeared at 300–400°C, parallel to the disappearance of ash WR. Simultaneously, peaks D and F (wavenumbers = 1400 cm–1 and 872 cm–1, respectively) appeared, which may not cause ash WR. These findings highlighted the heating effect on WR and the functional groups of litter ash, providing insights into post-fire soil hydrology. To reflect real field conditions, further studies should focus on variations in oxygen availability, heating rates, and moisture conditions.

Effect of Different Types of Soil Amendments on the Soil Aggregate Stability in Eleusine coracana-Grown Soil

2025-11-08T08:22:45Z

Title: Effect of Different Types of Soil Amendments on the Soil Aggregate Stability in Eleusine coracana-Grown Soil Authors: Wijeysingha, I.S.; Leelamanie, D.A.L.; Liyanage, T.D.P. Abstract: Stability of aggregates plays a crucial role in determining the physical health of soils. Soil amendments applied in agriculture may induce various properties, such as soil water repellency (SWR), which can influence the stability of aggregates. This study examined the effects of different soil amendments and their SWR on aggregate stability in Eleusine coracana (finger millet) grown soil. Cattle manure (CM), water-repellent leaf litter (Casuarina equisetifolia, CE), CE-derived biochar (BCCE), and quick lime (CaO) were mixed with sieved surface soil (3% CM, 3% CE, 3% BCCE, 1% CaO). Only soil was used as the control. The experiment followed completely randomized design with treatments in triplicate. Soil mixtures were filled into polybags (3750 g per bag) while maintaining the homogeneity of the bulk density for treatments. The moisture content was initially maintained at 80% of the field capacity of soil (450 cm3 per polybag) to ensure initial homogeneity. Germinated E. coracana seeds were transplanted and kept in a protected house. Initially, the SWR of mixtures was determined using the water drop penetration time (WDPT) test. At the 10th week, all aggregates were separated into two-equal (7 cm) layers (TL: top layer and BL: bottom layer) of each polybag and the percentage of water stable aggregates (% WSA) was determined using wet sieving apparatus. The 3% CE amended sample showed slight SWR, while others were non-repellent. The 3% CE amended sample showed the highest % WSA (TL: 99.21% and BL: 99.23%, p<0.05) due to the high initial hydrophobicity of CE. The control showed the lowest % WSA (TL: 76.17% and BL: 75.52%, p<0.05). Results showed that the slightly repellent 3% CE significantly enhanced the % WSA. SWR reduces the water entry into the aggregates and lowers pressure buildup, enhancing their resistance to disruption. Results validation under field conditions is required to ensure field applicability.