Southwest India Research Articles

The Influence of Land Use and Land Cover Transitions on Hydrology in a Tropical River Basin of Southwest India

The Influence of Land Use and Land Cover Transitions on Hydrology in a Tropical River Basin of Southwest India

Fractionation of Sediment-Bound Nitrogen: Bioavailability and Contamination Status of the Nutrient in Thrissur Kole Wetlands, Southwest India

ABSTRACT Fractionation of sediment-bound nitrogen (N) in Thrissur Kole wetland was carried out to assess the mobility, bioavailability, and nutrient contamination status. Various N fractions were extracted using KCl equilibrium extraction method, and the concentration of each N fraction was analyzed by spectrophotometric method. Dominance of ammonia during all seasons was due to dissimilatory NO3 − reduction to NH4 + and direct inputs from agriculture fields. Enrichment of urea during post-monsoon (181.78 ± 8.47 ppm) was attributed to fertilizer sources. NO3 −-N deficit at central zone of the study area (monsoon and post-monsoon) was due to the anoxia. Comparatively higher values of NO2 −-N during monsoon (0.07 ± 0.02 ppm) was due to the land run-off, leaching of fertilizers from agriculture fields, and higher rate of denitrification. Elevated content of total N [1819.94 ± 40.20 ppm (pre-monsoon); 3061.62 ± 13.21 ppm (monsoon); 2763.44 ± 9.65 ppm (post-monsoon)] reflected the inputs from in-situ production, agriculture, terrestrial run-off, waste disposal, and guano as well as carcass of birds. Average contribution of bioavailable N to total N was higher (36.16%) indicated the possibility for eutrophication risk during pre-monsoon. Agriculture dominated regions recorded severe contamination and eutrophication risk as indicated by organic pollution index, organic nitrogen index, and phosphorous pollution index.

Understanding mobility and immobility choices in vulnerable coastal settlements: insights from southwest India

ABSTRACT This study explores the influence of social, environmental, governance, and other household factors on migration decision-making in hazard-affected coastal areas in southwest India. Through nearly 900 interviews with households residing in these vulnerable areas and with households that have migrated elsewhere, this paper analyses the determinants that influence the propensity for migration versus staying, as well as for voluntary immobility versus involuntary immobility. Logistic regression was used to distinguish significant factors. The results showed that governance factors and the extent of impact were the most influential in migration decision-making, while social and household factors were the most relevant in determining voluntary non-migrants. The decision to migrate was found to be strongly influenced by post-disaster rehabilitation assistance by the government, while the decision to stay was influenced by the kind of coastal protection measures that were in place. These insights have significant implications for migration and planned relocation policies and can be leveraged to design more effective interventions for both immobile and migrating populations.

Insights into the seasonal distribution of microplastics and their associated biofilms in the water column of two tropical estuaries

The present study describes the seasonal distribution of microplastics (MPs) and their associated biofilms in the water column of the Netravathi-Gurupura estuary, southwest India. An average abundance of 8.15 (±3.81) particles/l and 1.14 (±0.78) particles/l was observed during the wet and dry seasons, respectively. Fibres, films, and fragments accounted for majority of the microplastics. Polyethylene terephthalate, polyethylene, polyurethane, polyester, polystyrene, and high-density polyethylene were the major polymers. The risk assessment revealed a low Pollution Load Index, but the Polymer Hazard Index showed higher toxicity. Diatoms from nine genera were observed attached to the microplastic samples with Amphora and Navicula spp. reported in both estuaries during both seasons. The considerable diversity of diatoms, along with other microbial groups, in microplastic-associated biofilms in this study, highlights the urgent need to understand the structure and development of microplastic-associated biofilms and their role in the vertical and horizontal transport of microplastics in tropical estuaries.

Microplastics in the Surface Waters and Sediment in an Agrarian Part of Vembanad-Kol Wetlands, the Largest Ramsar Site—Southwest India

Microplastics in the Surface Waters and Sediment in an Agrarian Part of Vembanad-Kol Wetlands, the Largest Ramsar Site—Southwest India

Dental Erosive Wear Assessment amongst Different Age Groups Utilising Basic Erosive Wear Examination: An Epidemiological Study

Introduction: The study aims to assess the prevalence of erosive tooth wear and risk levels amongst different age groups utilising Basic Erosive Wear Examination (BEWE) amongst the population of South West Coastal India. Materials and Methods: One hundred and sixty healthy people participated in the research (n = 32 per group). Using sextants and the BEWE, index (0–18) allowed for the evaluation of erosive tooth wear. Questionnaires supplemented clinical data. Each participant was assigned to groups based on the severity of their erosive wear: high (BEWE sum ≥ 14), moderate (BEWE sum 9–13), low (3–8) and none (0–2). Results: There is no significant difference in the degree of erosive tooth wear across different age groups (χ2– 20.11, P – 0.067 [not-significant]). There is a significant difference in response to questions across different age groups (χ2 – 487.21, P – 0.01 [significant]). Conclusion: The prevalence of erosive tooth wear grows as individuals age. Older age groups, patients who are at a higher risk level require a more comprehensive form of treatment. The aetiology of dental erosion remained unknown to the patients, indicating a deficiency in their understanding of erosive tooth wear.

Exploring extended-spectrum beta lactamase resistance in Vibrio parahaemolyticus and Vibrio cholerae within the tropical mangrove ecosystem of southwest India.

Multidrug-resistant pathogenic vibrios are a crisis of concern as they cause multiple illnesses, including gastroenteritis in humans and acute hepatopancreatic necrosis in aquaculture. In the current study, we investigated the prevalence of the beta-lactamase gene CTX-M-group 1 in Vibrio spp. (Vibrio cholerae and Vibrio parahaemolyticus) from the water and sediment of urban tropical mangrove ecosystems of Kerala, southwest India. A total of 120 isolates of Vibrio spp. were tested for antibiotic susceptibility to 14 antibiotics. In water, ampicillin resistance was very high in isolates of V. cholerae (94.1%, n = 17) and V. parahaemolyticus (89.1%, n = 46). 26.9% of V. parahaemolyticus and 14.2% of V. cholerae harbored the CTX-M-group 1 gene in water samples. Compared to V. cholerae, the CTX-M-group 1 gene was exclusively hosted by V. parahaemolyticus (49%) in sediment samples. A significant difference in the prevalence of the CTX-M-group 1 gene was observed among Vibrio spp. in both water and sediment samples (p < 0.05). The results revealed the presence of multidrug-resistant and beta-lactamase harboring Vibrio spp. in mangrove ecosystems, which may have evolved as a consequence of the misuse and abuse of broad-spectrum antibiotics as prophylaxis in human health care and aquaculture.

Seasonal shift in trophic status induced by bacterial metabolic activity in tropical mangrove-dominated estuaries of Southwest India

Seasonal shift in trophic status induced by bacterial metabolic activity in tropical mangrove-dominated estuaries of Southwest India

Evaluation of InBios Scrub Typhus Detect IgM Rapid Test in Acute Fever Cases from Southwest and East India.

Scrub typhus is clinically undifferentiated from other aetiologies for acute febrile illness such as enteric fever, dengue, malaria, and leptospirosis. Rapid ELISA tests are being used as an alternative to immunofluorescence assay in tropical countries. In this study, we compared and evaluated commercially available InBios Scrub Typhus Detect IgM Rapid Test (USA) for diagnosing human scrub typhus infection using archived and prospectively collected samples against the reference standard, InBios Scrub Typhus Detect IgM ELISA (USA). The data analysis of archived samples on rapid test revealed a moderate sensitivity of 53.92% and a specificity of 100%. Meanwhile, prospective serum samples demonstrated higher sensitivity and specificity of 96.4% and 94.6%, respectively. The InBios Scrub Typhus Detect IgM rapid test can be a good point-of-care assay during surveillance, outbreak investigations, and case identification.

Metal partitioning in sediments and risk assessment of a ramsar site-Cochin estuary, South West India

Geochemical partitioning of sediment bound metals in Cochin estuary were determined by sequential extraction to unravel the processes controlling their distribution, mobility and contamination status. Most of the metals recorded higher content at residual and exchangeable fractions. Abundance of Cd, Zn and Mn in bioavailable form (promoted by surface adsorption on fine grained sediments) was sourced to industrial operations, municipal sewage and agriculture effluents. Pyrite formation effectively controls the fraction distribution of redox sensitive elements- Mn and Fe. Scavenging by Fe-Mn oxide was dominant process regulating the accretion of metals -Zn, Ni, Cr, Co, Cd, Mn whereas organic matter complexation facilitate the accumulation of the metals-Mn, Co, Cu and Zn. Contamination due to Zn and Cd was substantiated by enrichment factor (range for Zn: 4.42–57.22; range for Cd: 0.02–0.37), contamination factor (range for Zn: 0.51–22.19; range for Cd: 3.30–60.67 and geoaccumulation index (range for Zn: 0.10–4.45; range for Cd: 0.66–12.18). Elevated PLI (Range: 0.19–1.58) indicated metal inputs from anthropogenic activities. Potential ecological risk values >40 implied that Cd, Zn and Pb can induce risk to the ecosystem.

Tracing the Late Quaternary coastal evolution of Central Kerala, India, around the lost ancient port Muziris using multi-proxy study of the sedimentary archives

The Central Kerala coast in Southwest India serves as a valuable natural archive for studies of the Late Quaternary coastal evolution, palaeoclimate, and maritime trades. The coast is an archeologically and culturally significant region in South India, located in the mouth of the longest river in Kerala, the Periyar River. The riverbank of the Periyar at its mouth is believed to host the ancient port Muziris, whose remnants are found in the areas around where the Periyar River joins the Arabian Sea. Sea level oscillations and climate variabilities in the past have played a pivotal role in the destruction of the Muziris port. Recent excavations unearthed many artifacts from nearby areas of the river confluence; however, the exact location of the port remains unresolved. The present study is an attempt to trace out the coastal evolutionary processes and palaeoclimatic conditions that prevailed in the area during the Late Quaternary period using three drilled cores retrieved from this stretch of the coastal lands. A multi-proxy approach, combining geochemical, mineralogical, palynological, and geochronological tools was used in the study. The Holocene deposit in the study area is composed mainly of sand and clay-dominant sediments that fall within an age range of 1.1–8.1 cal kyr BP, whereas the underlying sedimentary sequence dates to a maximum of 31.5–37.9 cal kyr BP. The inorganic and organic elemental compositions, together with the textural and palynological attributes, indicate that Holocene sedimentation occurred here under fluctuating environmental conditions with significant changes in climate and sea level positions. The upper part of this section bears the signature of the humid depositional environment that prevailed during the Late Holocene when sand-dominated sediments were deposited and brought in under the influence of longshore drift. The sediments from the lower part of the section carry the signature of the Holocene transgression when deposition took place under submerged conditions with considerable marine influence but receiving significant terrestrial inputs. The study highlights the location of the historically significant lost ancient port of Muziris at Kodungallur near the mouth of the Periyar River. A three-fold evolutionary model proposed for the coastal segment revealed that the location of the Muziris port was part of the Periyar River near Kodungallur, as mentioned by the historians, and the settlement near Pattanam may be considered a satellite township of the ancient Muziris port.

Drivers and mechanisms of heatwaves in South West India

Drivers and mechanisms of heatwaves in South West India

Microplastic pollution in the Chapora River, Goa, Southwest India: spatial distribution and risk assessment.

The amount of information available on the microplastic (MP) contamination in Goa's riverine water systems is currently limited. The abundance, size, colour, and polymer composition of microplastics in Chapora River surface water were investigated in this study. MPs in Chapora River surface water ranged from 0.1 particles/L (station 13) to 0.47 particles/L (station 5). The mean (± standard deviation) MP concentration was 0.25 (± 0.13) particles/L. Fibre was the dominant shape (77.15%), followed by fragments (12.36%), films (9.36%), and foam (1.12%). Most MPs were found in the 0.1-0.3mm size range, then in the 0.3-1mm and 1-5mm. The dominant type of polymer studied was polyethylene terephthalate (PET; 46%), followed by high-density polyethylene (HDPE; 14%), polypropylene (PP; 5%), and polystyrene (PS; 1%). The risk assessment study indicated high risk with respect to PHI, while PLI shows low risk in the area. The source of MPs was mostly anthropogenic in nature in the region. When compared with other tropical rivers, MP pollution was relatively lower in the Chapora River. Nevertheless, the baseline data will help the local administration take mitigation measures to reduce the impact of MP pollution in the region.

Human Immunodeficiency Virus Preexposure Prophylaxis Awareness and Acceptability among Men Who Have Sex with Men and Transgender Persons in India: Systematic Review and Meta-analysis.

With increasing importance being given to preexposure prophylaxis (PrEP) for human immunodeficiency virus prevention among men who have sex with men (MSM) and transgender persons (TG), we undertook a systematic review and meta-analysis of PrEP awareness and acceptability among these key populations in India, and their sociodemographic and behavioral determinants. The systematic review was registered with PROSPERO (CRD42023390508). Studies were included if they provided quantitative data on PrEP awareness or acceptability among MSM or TG in India. MEDLINE, Scopus, Web of Science, and Embase were searched from inception to February 29, 2024, using keywords and database-specific terms. Relevant websites were also searched. Critical appraisal was done using the Joanna Briggs Institute Checklist for Prevalence Studies. Random-effects meta-analysis was done for common outcomes reported by the studies. Reporting was as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 statement. Ten studies providing cross-sectional data, mostly from South West India, were included for qualitative synthesis. All were conducted in settings where PrEP was not available. The pooled prevalence among MSM and TG was 18.7% (95% confidence interval [CI] 8.7%, 28.7%) for awareness and 79.8% (95% CI 57.4%, 100.0%) for willingness to use daily oral PrEP. This review highlights the felt need for PrEP among MSM and TG in India. Further research is needed to understand user attitudes in different parts of the country.

‘Our team will definitely win the cup’: the Keralan support of Brazil and Argentina during Men’s World Cup 2022

ABSTRACT At the end of 2022, the FIFA Men’s World Cup took place in Qatar, and Argentina won its third title. Among thr worldwide supporters, India, a nation that had never played at the event, caught my attention. This study focuses on the state of Kerala, a mainly rural zone in Southwest India, and its massive support for Brazil and Argentina. After a literature review on football in India, the globalization of football, and team rivalries, the study analyzes a few English-written news articles to understand such manifestation of fandom in Kerala, and focuses on the giant cut-outs to find the answer as to why Brazil and Argentina are the teams who received the biggest support. It concludes that the said support has social, political, mediatic, identitarian, and religious roots. The article ends with the question as to how these manifestations differ in different countries, states, championships, and religions.

Hydrogeochemical characteristics of Thrissur Kole Wetland, Southwest India

ABSTRACT Surface water samples collected from Thrissur Kole wetland (UNSECO-protected Ramsar Site) were analysed for hydrogeochemical characteristics. The objectives of this work were to: (i) study the spatial and seasonal variability in water quality and (ii) analyse the hydrogeochemical characteristics of different water types and suitability status for irrigation. Remarkable season-wise and station-wise variation in salinity was attributed to the mixing of freshwater and seawater. Relatively lower values of pH during post-monsoon were due to the freshwater discharge and mineralisation of organic matter. Besides natural sources, agriculture activities, and droppings from birds also serve as sources of nutrients in the wetland. The average relative abundance of major cations and anions was Cl- > Na+ > Mg2+ > K+ > SO4 2- > HCO3 - > Ca2+. In addition, the contribution of dissolved ions from tidal ingression was established by the dominance of magnesium and sulphate. Based on Piper plot, three major hydro-chemical facies (Ca–Mg-HCO3 type, Ca–Mg-Cl-SO4 type, and Na-K-Cl-SO4 type) were identified. Irrigational suitability of water throughout the wetland was excellent during monsoon as per irrigational water quality indices. Piper plot indicated that the surface water chemistry was controlled by silicate weathering with contribution from seawater ingression and anthropogenic sources.

Clinical and seasonal pattern of dengue in a tertiary care hospital of South West India.

Dengue is an emerging global viral disease with an increase 30-fold in incidence in the past fifty years. In the past decade it was restricted to only few a states of South and Northern India but in the recent past it has affected almost all the states in India. The objective of this study was to assess the clinical profile, trends and outcome of dengue cases. This retrospective record based cross-sectional study was conducted in tertiary hospital, Mangaluru in Southern India. The study population included all dengue positive cases diagnosed either by IgM Capture ELISA or Dengue Non-structural Protein NS1 antigen over a period of five years. Information from pre-recorded case sheets were used for data collection. The data was analyzed using SPSS Version 20. Results from the analysis have been expressed in percentages, means and graphs. The study included 401 dengue cases. Most cases were in the age range of 20-40 years with a male to female ratio of 3:2. Overall seropositivity rate was 23.94% with High IgM prevalence. Monthly distribution showed a maximum cases were in the months of June and July and minimum were in January and February. Among the study participants, 91.5% of patients recovered completely and 1.7% of patients had died. 6.8% of patients were discharged against medical advice. Dengue continues to be major public health problem in this part of the globe affecting mainly the working age group. Low seropositivity with High IgM prevelance makes dengue an important differential for febrile illness of vague nature and invokes the need for robust public health response to curb the hyper-endemicity.

Clinical and seasonal pattern of dengue in a tertiary care hospital of South West India

Background Dengue is an emerging global viral disease with an increase 30-fold in incidence in the past fifty years. In the past decade it was restricted to only few a states of South and Northern India but in the recent past it has affected almost all the states in India. The objective of this study was to assess the clinical profile, trends and outcome of dengue cases. Methods This retrospective record based cross-sectional study was conducted in tertiary hospital, Mangaluru in Southern India. The study population included all clinical dengue positive cases over a period of five years. Information from pre-recorded case sheets were used for data collection. The data was analyzed using SPSS Version 20. Results from the analysis have been expressed in percentages, means and graphs. Results The study included 401 dengue cases. Most cases were in the age range of 20-40 years with a male to female ratio of 3:2. Overall seropositivity rate was 23.94% with High IgM prevalence. Monthly distribution showed a maximum incidence in the months of June and July and minimum incidence in January and February. Among the study participants, 91.5% of patients recovered completely and 1.7% of patients had died. 6.8% of patients were discharged against medical advice. Conclusions Dengue continues to be major public health problem in this part of the globe affecting mainly the working age group. Low seropositivity with High IgM prevelance makes dengue an important differential for febrile illness of vague nature and invokes the need for robust public health response to curb the hyper-endemicity.

Accumulation of microplastics in bivalves within the Chandragiri River in South-Western India

The pervasive presence of microplastics within river ecosystems has a profound and often underestimated detrimental impact. These minuscule yet persistent particles have infiltrated diverse biological habitats, making their detrimental effects on aquatic life increasingly concerning worldwide. The ability of microplastics to accumulate within aquatic organisms further exacerbates this concern. Consequently, the monitoring of microplastic pollution in surface water environments has emerged as a crucial endeavour, offering invaluable insights into the extent of this ecological threat. This study delved into the contamination levels of microplastics within two bivalve species, Perna viridis and Villorita cyprinoides, along the Chandragiri River in Kerala and Karnataka, South-West India, spanning eight distinct locations. The investigation yielded a significant discovery, with a total of 667 microplastic particles extracted from 288 individuals. On average, each individual bivalve harboured approximately 2.31 ± 0.93 microplastic items. Notably, these microplastic particles exhibited a wide range of morphological characteristics, underscoring their diverse origins and pathways into the ecosystem. Furthermore, five polymer types of microplastics were unequivocally confirmed through FTIR-ATR analysis, shedding light on the types of plastics that pose a threat to the riverine ecosystem. The findings of this study contribute to a growing body of evidence highlighting the global threat of microplastic pollution, urging international collaboration and innovative solutions to prevent further contamination and remediate existing microplastic burdens in aquatic environments.

Microplastics in Scylla Serrata: A baseline study from southwest India

Scylla serrata plays a crucial role in India's seafood exports yet there exists limited understanding on the occurrence of microplastics (MPs) in these crabs. In this baseline study, we examined the presence of microplastics in the digestive tracts of S. serrata collected from the Kota mangroves, southwestern coast of India. Our analysis revealed the presence of 264 MPs in all the samples with an average (± standard deviation) of 29.33 (±11.53) MPs/Individual. The most dominant categories were fibres (98.86 %) and fragments (1.14 %). Primarily 0.1–0.3 mm (50.90 %) and 0.3–1 mm (37.65 %) size range dominated. The predominant polymers were polypropylene (33.71 %), high-density polyethylene (31.44 %), and polyethylene terephthalate (17.80 %). Scanning electron microscopy revealed extensive weathering on the surface of the microplastics. Risk assessments indicated severe risks to S. serrata due to microplastic ingestion emphasizing the need to protect delicate ecosystems like mangroves and the biota within.