Weathered granite soil (WGS) is highly water-sensitive and widely distributed across southern China, where the region's rainy climate contributes to geological hazards such as collapsing erosion, landslides, and ground subsidence. This study aims to elucidate the impact of this rainy climate on the deterioration of WGS by investigating the suffosion characteristics of granite residual soil (GRS) and completely weathered granite (CWG) at various stages of weathering. The research explores how suffosion affects their mechanical properties and microstructural features. A series of suffosion tests were conducted under controlled water pressure, followed by one-dimensional consolidation tests, cyclic triaxial tests, scanning electron microscopy, X-ray diffraction, and X-ray fluorescence analyses to analyze the deterioration mechanisms at both macro- and micro-scales. The results show that suffosion leads to the loss of fine particles and overall settlement of the soil samples. Microscopically, Mica is almost entirely lost, iron cementation is disrupted, and clay minerals, along with quartz and feldspar debris, are eroded, causing microstructural damage. The loss of minerals at the micro-scale exacerbates the formation of pores and cracks, increasing WGS porosity and promoting the progression of suffosion. On the macro-scale, suffosion alters the physical properties of WGS, with fine particle migration and loss leading to soil skeleton deformation, reduced stiffness, and decreased compressibility. Furthermore, a suffosion index is proposed, correlating microstructural changes with macroscopic mechanical parameters. This study has practical and theoretical significance for slope stability, collapsing erosion prevention, and surface subsidence mitigation in WGS in southern China.

Profenofos is one of the most widely used toxic organophosphate insecticides used in crop fields against various insect pests. The pesticide may spread into the environment through various sources, such as air, water, soil, etc. Therefore, there is a high risk of ingestion for animals and aquatic fauna. The present study aimed to assess the profenofos-induced hepatotoxicity, genotoxicity, and haematological abnormalities of the freshwater fish Channa punctatus, which can indicate the probable threat of this pesticide to other species, including humans. Freshwater fish Channa punctatus were exposed to two sub-lethal concentrations of Profenofos (0.078 and 0.157 mg/L). After 7 days of consecutive exposure, changes in haematological parameters, hepatic tissue histology, and genotoxic effects were evaluated. The total count of red blood cells (RBCs), white blood cells (WBCs), and haemoglobin (Hb) % was done. Along with the histological changes in hepatic tissues, genotoxic studies were also carried out. The study showed that profenofos induces different changes in the liver's haematology and histology and nuclear abnormalities in the erythrocytes of treated fish. The results indicate significant differences in RBC and Hb%, whereas marked elevations in WBC count were recorded. The histopathological study of the liver in the treated fish revealed some substantial changes like cell damage, distorted cell shape, vacuolations, etc. Some significant genotoxic effects of profenofos in the erythrocytes were observed, such as the induction of micronuclei, lobed nuclei, irregular-shaped nuclei, notched nuclei, and distorted nuclei. The results were statistically significant at the p < 0.05 level. The study explores the toxic effects of pesticides on the overall health of the fish species. Moreover, the study tried to focus on making decisions about using a tolerable prescribed dose of chemicals to minimize the risk of pesticides. People will also learn that the contamination of the insecticide profenofos is harmful to the aquatic ecosystem, and therefore indiscriminate measures should be avoided.

Pesticide contamination has become a major environmental concern with organophosphates such as chlorpyrifos emerging as major pollutants posing significant risks to both ecosystems and human health. Chlorpyrifos is widely used in agriculture to control pests, however due to its persistence, its accumulation in soils can lead to long-term environmental damage. The objective of this study was to isolate and characterize chlorpyrifos-degrading bacteria from a tobacco field exposed to intensive pesticide use in T & uuml;rkiye. To achieve this, a selective enrichment strategy was employed to promote the growth of chlorpyrifos-degrading microorganisms. Two distinct experimental setups were established to target both normally growing and slower-growing bacteria: the first involved a 4-week incubation with weekly subculturing as described in the literature, while the second applied an 8-week incubation with biweekly subculturing. At the end of the enrichment period, bacterial loads were compared between the two groups. Four of the nine bacterial isolates were obtained from the newly tested long-term setup. Among all isolates, members of the genus Pseudomonas exhibited the best adaptation to the prolonged enrichment conditions. Additionally, isolates belonging to the genera Klebsiella, Sphingobacterium, and Peribacillus were isolated from the normally growing group. Two isolates (AB4 & AB15), identified as Sphingobacterium thalpophilum, were determined to be novel chlorpyrifos degraders. This is the first reported study from T & uuml;rkiye focusing on the biodegradation of chlorpyrifos by native soil bacteria. The findings revealed that various ecological areas, constitute potential sources for new microbial metabolic processes and these bacterial strains can be used in bioremediation studies.

Currently, there is a growing concern for human health with the rise of environmental pollution. Water contamination and health problems had been understood. Sanitation-related health issues have been overcome in the greater part of the world. Progressive industrialization has caused a number of new pollutants in water and in the atmosphere. It is a growing concern for the human health, especially upon the reproductive health. Current researchers provide a strong association between the rising concentrations of ambient pollutants and the adverse health impact. Furthermore, the pollutants have the adverse effects upon reproductive health as well. Major concern is for the health of a pregnant woman and her baby. Maternal-fetal inflammatory response due to the pollutants affects the pregnancy outcome adversely. Preterm labor, fetal growth restriction, intrauterine fetal death, and stillbirths have been observed. Varieties of pathological processes including inflammation, endocrine dysfunction, epigenetic changes, oxidative and nitrosative stress, and placental dysfunction have been explained as the biological plausibility. Prospective studies (systematic review and meta-analysis) have established that exposure to particulate matters (PM) and the nanoparticles (NP) leads to excessive oxidative changes to cause DNA mutations, lipid peroxidation and protein oxidation. Progressive industrialization and emergence of heavy metals, micro- (MP) and nanoparticles (NP) in the atmosphere and in water are the cause for concern. However, most of the information is based on studies from industrialized countries. India needs its own country-based study to have the exact idea and to develop the mechanistic pathways for the control.

Chlorpyrifos contamination is a currently on-going issue with significant environmental impacts. As such, rapid and effective techniques that remove chlorpyrifos from the environment are urgently required. Here, a strain of Pseudomonas nitroreducens W-7 exhibited exceptional degradation ability towards both chlorpyrifos and its major metabolite 3,5,6-trichloro-2-pyridinol (TCP). W-7 can effectively reduce the toxicity of chlorpyrifos and TCP towards a variety of sensitive organisms through its superior degradation capacity. W-7 demonstrated efficient soil bioremediation by removing over 50 % of chlorpyrifos (25 mg/kg) from both sterile and non-sterile soils within 5 days, with significantly reduced half-lives. Additionally, 16S rDNA high-throughput sequencing of the soil revealed that the introduction of W-7 had no significant impact on the soil microbial community. A pivotal hydrolase Oph2876 containing conserved motif (HxHxDH) and a bimetallic catalytic center was identified from W-7. Oph2876 was a heat- and alkali-resistant enzyme with low sequence similarity (< 44 %) with other reported organophosphorus hydrolases, with a better substrate affinity for hydrolysis of chlorpyrifos to TCP. The molecular docking and site-directed mutagenesis studies indicated that the amino acid residues Asp235, His214, and His282, which were associated with the conserved sequence HxHxDH, were crucial for the activity of Oph2876. These findings contribute to a better understanding of the biodegradation mechanism of chlorpyrifos and present useful agents for the development of effective chlorpyrifos bioremediation strategies.

As a class of emerging persistent organic pollutants (POPs), per- and polyfluoroalkyl substances (PFASs) are widely detected in the soil environment, posing a significant threat to the soil ecosystem and human health. Therefore, it is necessary to study the ecotoxicological effects of PFASs in soil. In this study, we conducted a comprehensive review of the toxic effects of PFASs on earthworms at the individual and sub-individual levels, including survival status, body weight, reproduction, oxidative damage, genes, metabolism, and so on. Results showed that earthworms exposed to certain concentrations of PFASs display various pathological symptoms on their body surfaces, a decrease in body weight and reproductive rate, and even death. The LC50 values of PFOS to earthworms (365-1404 mg/kg) are consistently lower than those of PFOA (544-1307 mg/kg) under the same exposure condition, indicating a higher toxicity of PFOS compared to PFOA. At the sub-individual level, PFASs may induce oxidative stress, DNA damage, aberrant gene expression, and metabolic disruption in earthworms. PFOS induced disruption of the nervous and metabolic system, PFHxS disrupted energy balance and elicited inflammation, and PFBS induced cell apoptosis in earthworms. Compared to PFOS, PFHxS may induce a greater degree of oxidative stress and damage, and 6:2 Cl-PFESA (F-53B) exhibited a greater propensity to disrupt the extracellular matrix and induce cellular ferroptosis and apoptosis in earthworms. At environmentally relevant concentration levels, PFOA induces significant dysregulation of pathways related to amino acid, energy, and sulfur metabolisms within earthworms. Bioavailability and bioaccumulation capacity of PFASs are important factors in determining their toxicological effects in soil, which is influenced by the molecular structure of PFASs and the combined effects of various environmental factors, such as soil organic matter composition and content, pH, PFAS concentrations and exposure duration. Finally, existing research deficiencies and future directions about the toxicological research of PFASs on earthworms are proposed, aiming to offer reference for ecological risk assessment of PFASs-contaminated soil.

Suffusion, a process whereby water gradually carries away fine particles from soil, is thought to be one of the possible reasons for the settlement or inclination of bridge piers after a major flood (delayed displacement). The aim of this study is to offer fresh insights into suffusion and its mechanical impact on the affected soil, with a specific focus on how it relates to bridge pier failures. Riverbed material replicated with relatively larger fine particles than those used in past studies which focused on soil in embankments or dikes. Through both monotonic and cyclic loading tests on soil samples with varying initial fines contents, while maintaining a constant relative density of 79%, several important discoveries are made. The small strain stiffness of suffused soil fluctuates as erosion occurs, along with a decrease in shear strength and an increase in soil contraction under monotonic stress. Furthermore, the research simulates the train loading exerted on the base soil of bridge piers susceptible to suffusion by subjecting the soil samples to cyclic loading both before and after erosion, mirroring practical conditions. The key findings of this study reveal that the stiffness of soil drops during erosion with no significant deformation of the soil. This leads to a large strain accumulation in the soil specimens under subsequent cyclic traffic loading. These findings highlight that the delayed settlement or inclination of bridge piers under cyclic or train loading after major flood is possibly due to suffusion in the base soil of the piers. (c) 2024 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society. This is an open access article under the CC BY NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Fine-grained soils containing diatom microfossils exhibit unique geotechnical behavior due to their biological origins, but their strength properties controlled jointly by diatom content (DC) and stress history remain to be revealed. In this study, reconstituted diatomaceous soil was prepared by mixing pure diatom and kaolin powders in different proportions. These mixtures were subjected to undrained consolidated triaxial shear tests performed using the Stress History and Normalized Soil Engineering Properties (SHANSEP) procedures, revealing how the DC and stress history affect the soil strength. Adding diatoms improved the mixture strength, and a critical DC of approximately 20% was determined, beyond which the normalized undrained strength of the soil was considerably higher than that of common clay without diatoms. Also, a DC higher than 20% associates with the dilatancy of the studied soil with high OCR. Improving the strength of diatomaceous soil by adding diatoms differs essentially from the case of common clay because the plasticity index of the former remains almost unchanged. New formulas incorporating DC and OCR are proposed for predicting the strength of diatomaceous soil, and data for several well-studied soils confirm their validity. This study improves the understanding of fine-grained soils with biological origins and provides important data regarding the mechanical behavior of diatomaceous soil.

Long-term geotechnical slope deterioration, influenced by weathering and meteorological factors, presents stability challenges to infrastructure. Wetting and drying cycles lead to pore water pressure variations, causing deformations and slope failure. Studies on glacial tills which investigate deterioration in geotechnical slopes focus on variables like pore water pressure, soil water retention, compaction, freeze-thaw cycles and cracking. This research conducts a preliminary assessment of an Irish glacial till-cut slope, establishing a data-driven foundation for long-term slope behaviour studies. Data analysis, geospatial modelling and numerical simulations were performed on a cut slope in Castleblayney (Ireland), considering short-term/undrained and long-term/drained conditions. FLAC/Slope and Scoops3D were used for 2D and 3D slope stability analyses, applying the First-Order Second Moment (FOSM) probabilistic approach to assess how minor soil property changes affect slope stability, including long-term deterioration scenarios. The study underscores the importance of precise instrument placement within Irish glacial till geotechnical cut slopes, particularly at the uppermost part where shallow and deep failures coincide under long-term and short-term scenarios. This informs strategic instrument positioning for accurate slope deterioration investigations. This research lays the groundwork for understanding mechanisms driving geotechnical slope deterioration and provides insights for future studies on geotechnical asset deterioration models in Irish glacial tills.

In recent years, local scour has occurred on the pier foundations of river bridges during heavy rain and river flooding, often resulting in bridge collapse and outflow. This study focused on the characteristic displacement, called delayed displacement, of the river bridge pier. The critical displacement of the piers was first observed several days after the flood when the train passed and not immediately after the flood. The authors hypothesized that one of the possible reasons for the delayed displacement is the suffusion of the supporting ground beneath the pier foundation during the flood, followed by a compressive behavior due to the collapse of the soil skeleton under repeated traffic loads. Accordingly, this study performed erosion tests simulating flood and cyclic loading tests simulating train passage using a triaxial test apparatus to check the validity of this hypothesis. In some test cases, suffusion without any deformation occurred in the erosion test but deformed in the cyclic loading test just after the erosion test. This behavior matches the behavior of delayed displacement. It was also suggested that the risk of the delayed displacement becomes high when the soil skeleton was assumed to primarily comprise fine particles, and the void ratio and hydraulic gradient were high. By contrast, when the soil skeleton was assumed to primarily comprise coarse particles, suffusion occurred in the erosion test, but did not deform in the subsequent cyclic loading test. Thus, the risk of delayed displacement is considered to be low when coarse particles are dominant. Furthermore, clear relationship between suffusion and the consequent reduction in soil stiffness cannot be observed. This result indicates that no significant change in the stiffness occur in the supporting ground of the pier foundation at the stage immediately before the delayed displacement. Thus, identifying the deterioration in the stability of the piers through impact loading test, which is based on the concept that local scour reduces the natural frequency of the bridge pier, is difficult.