The potential adverse effects of pharmaceuticals and personal care products (PPCPs) on the environment and human health have attracted a lot of research interest due to their abundance in river systems. The temporal and spatial distribution of PPCPs in river water around China and India is comprehensively examined in the present study. Common sources of PPCPs, their behavior, and ultimate fate are discussed in detail, with reported concentrations of antibiotics, hormones, antimicrobial agents, biocides, and preservatives ranging from ng/L to μg/L, indicating their continuous discharge into riverine environments. This chapter examines the environmental impacts of PPCPs, emphasizing their persistence and the need for continued research and mitigation approaches.

This study investigates the seasonal dynamics and fluxes of dissolved organic carbon (DOC), dissolved silica (DSi) and dissolved nitrate in the Sharavati River catchment, Western Ghats, and their transfer to the estuary. DOC exhibited moderate seasonal and spatial variability, with maximum concentrations in pre- and post-monsoon (up to 5.66 mg/L) linked to leaching of forest litter and soil organic matter mobilization, while monsoon values were lowest due to dilution. DSi showed spatial control over its concentrations across different seasons. DSi concentrations were highest upstream (27 mg/L in pre-monsoon 2019) due to intense silicate weathering, but declined downstream under the influence of damming, biological uptake, and dilution. Nitrate concentrations exhibited strong seasonal as well as spatial control. Nitrate peaked during the enhanced monsoon by cyclonic events (up to 1.56 mg/L), reflecting runoff and agricultural inputs, whereas pre-monsoon levels were minimal due to reduced discharge and enhanced denitrification. The estimated annual fluxes to the estuary were 1,966 t yr⁻¹ for nitrate, 6,610 t yr⁻¹ for DOC, and 36,000 t yr⁻¹ for DSi. Relative to other west-flowing rivers of India, the Sharavati displayed lower nitrate and DOC fluxes (65 and 104 kg km⁻² yr⁻¹, respectively), consistent with its largely forested catchment, while its DSi flux (753 kg km⁻² yr⁻¹) was moderate, shaped by lithology and reservoir regulation. These findings underscore the role of monsoonal effects enhanced by cyclones and damming in controlling nutrient and carbon export. This study contributes to biogeochemical datasets assessing Arabian Sea ecosystem responses.

Arsenic pollution in groundwater is a global health concern that requires long-term cleanup techniques. This study presents Rhodopseudomonas palustris biomass as a unique, eco-friendly option for arsenic detoxification, achieving levels below the WHO/EPA limit of 10 mu g L--(1) through synergistic adsorption and enzymatic methylation. The biomass can successfully adsorb arsenate [As(V)] and arsenite [As(III)], with capacities of 92 +/- 0.5 mu g g(-)(1) and 127 +/- 0.5 mu g g(-)(1), respectively, following pseudo-first-order kinetics at near-neutral pH (6.7). HPLC-ICP-MS analysis showed that As(III) transforms into less dangerous dimethylarsinic acid (DMA) at 1.30 +/- 0.28 mu g L--(1), whereas As(V) displays minor methylation (<0.01 mu g L--(1) DMA) as estimated by mass balance calculations, thus emphasising As(III)'s higher reactivity. FTIR and FESEM-EDAX confirm that arsenic binds to carboxyl and phosphate groups on the biomass surface. The technique maintains 70 % efficiency after three repetitive adsorption cycles, increasing cost-effectiveness. Life Cycle Assessment reveals an environmental footprint of 2.34 kg CO2-eq/m(3), 0.015 kg PO43--eq, and 0.00015 kg 1,4-DCB-eq, offering a significant improvement over reverse osmosis (3.5 kg CO2-eq/m(3)) and adsorption-only systems (2.8 kg CO2-eq/m(3)) by leveraging biological methylation to minimize emissions and toxicity. This dual-functional strategy, which combines strong adsorption and biotransformation, provides a scalable, long-term sustainable solution for arsenic remediation in resource-constrained areas, aligning with global water safety goals and advancing bioremediation paradigms.

Spatiotemporal analysis of glaciological phenomena provides a robust assessment of a glacier's health. Glacier surface facies (GSF) are direct indicators of the state of snow and ice within a glacier. However, long-term analyses of GSF via optical satellite products presents challenges stemming from data availability, weather conditions, and variations in mapping methodologies. In this study we present the first decadal analysis of GSF in Svalbard using optical satellite data. Utilizing unsupervised classification on images of the Vestre Broggerbreen glacier from 2013 to 2023, we identify and quantify the variations between facies observed on the images and their classified spatial distributions. The identified facies comprise of snow, firn, glacier ice, and dirty ice, with a fifth thematic class of shadowed snow. In certain imagery, snow and firn are labelled as 'snow 1' and 'snow 2' due to the derived reflectance and appearance of firn differing from established patterns in the literature, while remaining spectrally distinct from snow. Our analysis suggests that shadowed snow induces the most misclassification in overall assessment of GSF. Shadowed snow and dirty ice produce convoluted spectral reflectance that in combination with the overall darkening of the glacier severely misrepresented firn, underreported dirty ice, and produced inaccurate maps. Spatially, dirty ice was classified with a lower distribution in 2023 (0.49 km2) than in 2013 (0.58 km2). Moreover, firn/snow 2 was classified as a larger area in 2023 (1.01 km2). These results indicate a pressing need to identify long-term trends affected by scene-to-scene distortions. Our future experiments involve multi-decadal supervised analyses of GSF in the for refinement of supraglacial monitoring with multispectral data.

The seasonal changes of major ions in the aerosols around a coal-fired thermal power plant in southwestern India, is the primary objective of this study. Data collected during one-year period shows that both natural and anthropogenic sources have an impact on the samples. Sea salts from the Arabian Sea and the weathering of silicate rock, or mineral dust, have major impact on aerosol samples from natural sources, whereas contributions from fly ash, vehicular emission are anthropogenic. Principal component analysis and thematic maps support this finding. The distance-wise distribution of major ions and wind backward trajectory analysis indicated that anthropogenic activities have a significant impact on the pre-monsoon and post-monsoon samples than on the monsoon and early-monsoon seasons. Major Findings: 1. In the study area, major ions shows more temporal variations than spatial; the distance wise distribution of major ions, thematic maps and PCA analysis reflects that the samples are influenced by both natural and anthropogenic sources. 2. In monsoon season, the major ions show low concentration compared to pre-, early-, and post-monsoon seasons. This could be due to the impact of heavy rains resulting in the dilution in the concentrations.

Microplastics (MPs) have emerged as ubiquitous and persistent pollutants that impact all compartments of urban and mountain environments. However, studies combining abiotic and biotic components to assess MPs abundance and characterisation from remote mountain catchments of the Himalaya are still limited. This study examined abundance, types, and ecological risks of MPs in abiotic (surface water, water column, snow) and biotic (fish) components of Manasbal Lake, an ecological hotspot in the Kashmir Valley, western Himalaya. MPs were extracted using density separation and subsequently examined microscopically to determine their abundance, shape, color, and size. The concentration ranges were observed at 59–188 MPs/L in surface water, 8–15 MPs/L in water column, 11–18 MPs/L in snow, and 7–13 MPs/individual in fish samples. The MPs shape, color and polymer composition of biotic and abiotic components were dominated by fibers, transparent color and polyethylene terephthalate (PET) type, respectively. Most of the MPs observed were in the size range of 0.1–1 mm, with significant contributions from local pollution sources. We observed higher abundances of MPs away from stream inlets or residential areas, suggesting complex hydrodynamics and wind-driven surface transport in the lake. Risk assessment indices reveal that fibers exhibit the highest risk levels, posing a significant risk to the lake ecosystem. Further, a comparative analysis with other regional western Himalayan Lakes highlights the dominance of fiber MPs, emphasizing the need for multidisciplinary research efforts to address the growing concern for MPs contamination. This study underlines the necessity for integrated catchment-scale land-use planning while advancing our understanding of MPs pollution dynamics in lake ecosystems of the western Himalaya.

Geological archives can be examined via multiple proxies to uncover significant information about historical environmental changes. In comparison to single proxy approach, the use of multiple proxies can provide better resolution of the paleoenvironmental record. Thus, in the present study, to understand the paleoenvironmental conditions in the Kali coast in southwestern India, sedimentological, geochemical and isotopic (210Pb, 137Cs) proxies were used. The findings demonstrated that, in previous decades, the sedimentation rate varied from 0.5 to 1.0 cm/year under conditions with relatively higher hydrodynamic energy that were more common and fluctuating, allowing for larger sand particle deposition. However, in more recent years, finer particle deposition towards the surface has been observed under conditions with lower and more stable hydrodynamic energy, with a sedimentation rate of 1.87 cm/year. Additionally, the finer fractions displayed a strong correlation with the metal distribution, which was mostly governed by Fe-Mn oxides. Furthermore, it can be revealed that the environment was warm, humid, and marine-like between 1995 and 2000 based on chemical weathering intensity values and Rb/K ratios. A subtle shift to a freshwater habitat with relatively less warm, less humid climate occurred between 2000 and 2020. Therefore, similar research with longer depositional histories coupled with multiple proxies can help predict the future climatic shifts in decadal time scales.

Arsenic contamination continues to pose a critical challenge to environmental safety and public health due to its widespread presence in natural resources such as groundwater, soil, and air. Long-term exposure to arsenic is linked to a range of health issues, including various cancers, skin disorders, neurological dysfunction, infertility, and cardiovascular disease. While natural geological processes contribute to its release, human activities, such as mining operations, excessive use of agrochemicals, and industrial effluents, significantly amplify arsenic levels in the environment. This article explores bioremediation as a sustainable and effective approach for arsenic removal. Specific microbial strains, including Rhodopseudomonas palustris, Bacillus, and Shewanella, demonstrate strong arsenic resistance and detoxification capabilities through enzymatic processes such as methylation, oxidation, and reduction. Key enzymes, such as ArsM and AioBA, enable these transformations. Moreover, advances in genetic engineering further enhance microbial efficiency, achieving arsenic elimination rates nearing 99.7%. Additionally, rhizospheric technologies that combine plant-microbe interactions with nanomaterials such as nano zero-valent iron (nZVI) offer promising solutions for treating contaminated agricultural soils and aquifers. Despite these innovations, environmental uncertainties and the need for scalable, long-term implementation remain pressing concerns. This review highlights the potential of integrated microbial and biotechnological methods to support safer, more resilient remediation strategies and urges cross-sector collaboration to address arsenic pollution holistically and sustainably.

The emergence and spread of antimicrobial resistance (AMR) pose global health threats, with wastewater treatment plants (WWTPs) as hot- spots for its development. Horizontal gene transfer facilitates acquisition of resistance genes, particularly through integrons in Escherichia coli. Our study investigates E. coli isolates from hospital and municipal WWTPs, focusing on integrons, their temporal correlation along with phenotypic and molecular characterization of AMR. Samples from hospital and municipal WWTPs were collected over two seasons, pre-monsoon (March-May) and post-monsoon (December-February). From the hospital (hWWTP) and municipal (mWWTP) influents, 45 and 172 E. coli isolates were obtained, respectively. E. coli from hWWTP exhibited significantly higher resistance rates than mWWTP to most tested antimicrobials except tetracycline. The hWWTP isolates showed a higher prevalence (86.7%) of multidrug resistance (MDR) compared with mWWTP (48.3%). The proportion of MDR isolates from mWWTP nearly doubled in the post-monsoon season. Integron positivity was 17.7% (hWWTP) and 19.7% (mWWTP) with common gene cassettes conferring resistance to trimethoprim and aminoglycosides. Phylogroup analysis showed a predominance of group A in hWWTP and group B1 in mWWTP. The study highlights the role of hospital and municipal wastewater in disseminating AMR, with high rates of MDR E. coli and class 1 integrons detected.

Background Antimicrobial resistance (AMR) is a global threat driven mainly by horizontal gene transfer (HGT) mechanisms through mobile genetic elements (MGEs) including integrons. The variable region (VR) of an integron can acquire or excise gene cassettes (GCs) that confer resistance to antibiotics based on the selection pressure. Escherichia coli plays a significant role in the genetic transfer of resistance determinants to other Gram-negative bacteria. Current study is aimed to detect and compare integron-mediated resistance in clinical isolates of E. coli . Unique isolates of E. coli from urine or blood cultures were studied for their antimicrobial resistance patterns and integrons were detected using polymerase chain reaction assays followed by Sanger sequencing of GCs. Results During the study period, a total of 470 E. coli isolates were obtained, 361 (76.8%) from urinary and 109 (23.1%) from bacteremic sources. Class 1 integrons were detected in 66 (18.2%) and 26 (23.8%) isolates respectively. Urinary isolates of E. coli harbouring Class 1 integrons demonstrated significantly higher rates of resistance ( p < 0.05) for most antibiotics (12/16, 75%) compared to integron negative isolates. Although not statistically significant, similar differences were observed in bacteremic isolates. Among the urinary isolates, 27 (40.9%) had a VR, in which the most common GC array detected was DfrA17-AadA5 ( n = 14), followed by DfrA5 ( n = 4) and DfrA12 ( n = 3). Among bacteremic isolates, only 4 (15.3%) had a VR, all of which were carrying DfrA17 . The detected GC array correlated with the respective isolates’ phenotypic resistance patterns. Conclusion We found a strong correlation between integron positivity and trimethoprim resistance among E. coli from urinary sources. Although higher rates of resistance were observed in bacteremic isolates, they mostly carried empty integrons.

This study discusses the metal concentrations and sedimentological data from Lake L55, a dried, land-locked lake from Schirmacher Oasis, East Antarctica. Toxic metals in sediments are a major threat to the environment. Twenty-five surface sediment samples were analyzed for the presence of fifteen metals. The sedimentological data indicates that the sediments are predominantly sandy with low concentrations of silt and clay. The chemical weathering index for the sediments reflects low degree of weathering. Negligible concentrations of organic content were present in the sediments owing to the cold and dry conditions of the study area. The environmental pollution indices indicate elevated concentrations of Ba, Zn, As and Pb in the sediments. Barium could be supplied by the weathering of the quartzofeldspathic catchment rocks, while Zn, As and Pb could be supplied from the fuel burning for power generation and logistical activities, paint residue, and battery waste. The sediment quality guidelines were calculated for the sediments, and they indicate that the sediments have a 21% risk of being toxic. The pollution load index, potential ecological risk index (PERI) and toxic risk index (TRI) values suggest low toxic risk in the sediments of the lake.

We present a high-resolution record of environmental changes during the Mid-Late Holocene obtained from a lake sediment core covering the past 4.87 cal kyr BP in the Schirmacher Oasis, East Antarctica. The magnetic signal of Lake L6 was found to be primarily controlled by catchment-derived ferrimagnetic minerals. The period between 4.87 and 3.35 cal kyr BP is marked by several episodes of cold and warm conditions. Warm and wet conditions prevailed in the region from 3.35 to 2.43 cal kyr BP. Magnetic susceptibility values remained generally low indicating the pedogenic formation of fine magnetic grains. The high values of the chemical weathering indices reflected the warm and wet conditions conducive to chemical weathering. A transition to cold and dry conditions was observed at around 2.43 cal kyr BP, representing the Neoglacial cooling, with high values of magnetic concentration-dependent parameters. Following the Neoglacial period, a return to warm and wet conditions was observed at 1.63 cal kyr BP, coeval with the Medieval Climate Anomaly. Our record shows a Late-Holocene cooling marked by a sudden increase in magnetic susceptibility values, which could represent the Little Ice Age, followed by a shift to warmer conditions near the core top.

Study region: Sharavati River, Karnataka, India. Study focus: A small mountainous river system, Sharavati, was selected to study the impact of river damming on the hydrological cycle. Sharavati river flow is regulated by two dams, Linganamakki and Gersoppa. Despite the Western Ghats' global significance in controlling local and regional climates, the effects of damming on its hydrological cycles have received limited attention. A stable water isotopic approach was employed in the study. New hydrological insights for the region: The line-conditioned excess (lc-excess) was primarily negative across all seasons. Notably, the pre-monsoon season exhibited comparatively higher evaporation with high negative lc-excess, while the postmonsoon lc-excess values approached zero, indicating minimal evaporation. The sampling points from the dams exhibited very high evaporation signals, the evaporative loss during the pre-monsoon season from the Linganamakki reservoir was estimated as 10 %, and from the Gersoppa dam was 6 %. Consequently, groundwater sampled near the dams, plotted along the local evaporation line indicating recharge from the evaporated reservoir water. Damming has affected the hydrological cycle of the heavily regulated Sharavati River, transforming the entire catchment into a connected, narrow lake-like structure, especially during the pre-monsoon season. Since the Western Ghat river systems are regulated by many large and small dams, it is pertinent to study the impact of damming on the hydrological cycles of the entire system.

Submarine Groundwater Discharge (SGD) is the flow of fresh groundwater and recirculated seawater to the sea. SGD plays a crucial role in the transport of solute-rich terrestrial groundwater as well as recirculated seawater. We conducted seasonal investigations for two years on a tropical, high-rainfall occurring coastline in southwestern India to quantify the SGD from the nearshore. A combination of subsurface seepage meters and porewater samplers was used for an entire tidal cycle to estimate the seepage rates and to understand the processes controlling the discharge. The estimated seepage rates from this region are one of the highest reported in the world. This could be due to the large span of the highly porous coastal aquifer and the high annual rainfall (over 450 cm) in this region. The seepage rates are 754 cm/day, 572 cm/day and 296 cm/day for the pre-monsoon (February 2020), post-monsoon (December 2020) and pre-monsoon (February 2021) seasons, respectively and showed high spatial and temporal variability. The end-member concentrations of groundwater and seawater were used to delineate the fresh and recirculated SGD from the total seepage. The recirculated SGD (rSGD) dominates during all the seasons taking up to 99 % of the total SGD during the pre-monsoon seasons (February) and 70 % during the post-monsoon (December) season. The fresh SGD (fSGD) is low (-1 %) during the premonsoon season and increases up to 30 % during the post-monsoon. A considerable amount (0.1-10 % of the total SGD) of salinity enrichment was observed at the upper saline plume. We suspect this could be due to the evaporation of recirculated seawater due to ambient weather conditions. The fSGD in the study area is mainly controlled by the high inland hydraulic head, and the rSGD is regulated by the tides. The subsurface seepage meters used in this study eliminate the instabilities in seepage measurements and can be replicated in less-studied tropical coastal zones to quantify the volume of SGD entering the world oceans. The inferences reported can benefit the public and decision-makers in managing coastal groundwater resources and are interesting to the researchers working on delineating the hydrological and geochemical processes in the nearshore.

Judicial use of submarine groundwater discharge (SGD) can be a potential water resource for countries facing water scarcity. Very few studies report the fluxes of SGD into the oceans, especially from those countries that are located in the tropics and facing water scarcity. Another dimension of the SGD is its potential to control the biogeochemical cycles of nutrients and trace metals and the anthropogenic impact on the oceans. This work attempts to give an overview of the challenges and limitations involved in achieving the above. We have reviewed 1628 published literature that reported SGD in different contexts in the last 21 years (the Year, 2000 to this date). Several studies exist in bits and pieces across the world's coastline, with different methodologies adopted for identifying and quantifying the SGD. This compilation has attempted to extract these findings and listed the challenges and limitations in estimating the SGD fluxes. Significant challenges in quantifying the discharge include inconsistent sampling strategies adopted by researchers, uncertainties in modeling, spatio-temporal variations in discharge, extreme weather conditions, and difficulty in quantifying discharge at inaccessible areas (mangroves, large tidal flats, etc.). Some limitations discussed in this work include insufficient knowledge of coastal aquifer data, geology, and lack of historical hydrological data. Based on the critical analysis of the published literature, we recommend a few solutions that can provide a better resolution in the quantification of SGD. Decision makers and water conservation professionals will benefit from this work as they can suitably plan the water management, pollution control, and sustainable extraction of the SGD. We suggest strategies calling for assessments of SGD in areas of potentially significant discharge and developing new monitoring networks and strict policies for groundwater usage.