Source apportionment and health risk assessment of nitrate in foothill aquifers of Western Ghats, South India.

The present research reports the level of nitrate (NO3-), associated health risks and possible sources of contamination in groundwater from south India. Many samples (32%) are above or approaching the recommended level of NO3- for safe drinking water. The correlation analysis indicates different sources of NO3- contamination in different regions rather than a common origin. The isotopic measurements provide information about potential nitrogen sources contributing NO3- to the groundwater. Based on isotope analysis, the sources of NO3- in the groundwater of this region are likely to be from (a) septic sewage (b) organic nitrogen (animal and livestock excreta) (c) sewage (domestic & chemical fertilizers). Among the sample analyzed sewage, manure and septic sewage contribute 46%, 23% and 31% NO3- to groundwater. The HQ > 1 indicates non-carcinogenic health risk due to consumption of high NO3- in drinking water. Among the studied age groups, infants are exposed to higher risk than children and adults. Results indicate that groundwater of this region is polluted with NO3- due to anthropogenic activities. Continuous consumption of such water may pose serious health risk to the residents.

Case series of COVID-19 with spontaneous pneumomediastinum.

Spontaneous pneumomediastinum is a rare condition in viral pneumonia. However, it can arise spontaneously in COVID-19 patients with no other risk factors. Here we present four cases of spontaneous pneumomediastinum in patients with COVID-19 pneumonia with no other precipitating factors.

Clinical severity of COVID-19 with omicron variant predominance in relation to vaccination status, age, comorbidities- a single center in Selangor, Malaysia.

INTRODUCTION: Recently, the rapid surge of reported COVID-19 cases attributed to the Omicron variant of severe acute respiratory syndrome coronavirus (SARS-CoV-2) created an immediate concern across nations. Local information pertaining to the new variant of concern (VOC) is lacking. We aimed to determine the clinical characteristics of COVID-19 during a period of Omicron prevalence among patients hospitalised from February 1 to 21, 2022 at Sungai Buloh Hospital and to estimate the risks of disease progression presumably caused by this variant in association with gender, age, comorbidity, and vaccination status. MATERIALS AND METHODS: In this retrospective, singlecentered, retrospective cohort study, all hospitalised adults with laboratory-confirmed COVID-19, aged 18 and above, were recruited from February 1 to 21, 2022. Clinical characteristics, investigations, and outcomes were assessed. RESULTS: A total of 2279 patients aged 18 years and above with laboratory-proven COVID-19 were recruited and analysed, excluding 32 patients owing to incomplete data. Majority of the study population had a mean age of 41.8 ± 17.7, was female-predominant (1329/2279, 58.6%), had completed a primary series of vaccination with a booster (1103/2279, 48.4%), and had no underlying medical conditions (1529/2279, 67.4%). The risk of COVID-19-related disease progression was significantly lower in hospitalised patients under the age of 50 who were female, had no comorbidity, and had completed two doses of the primary series with or without a booster. [respectively, OR 7.94 (95% CI 6.16, 10.23); 1.68 (1.34, 2,12); 2.44 (1.85, 3.22); 2.56 (1.65, 3.97), p< 0.001]. CONCLUSION: During the period of Omicron prevalence, a favourable outcome of COVID-19 was strongly associated with female gender, age below 50, a comorbidity-free condition, and having completed immunization. With this new observation, it could help improve public health planning and clinical management in response to the emergence of the latest VOC.

Identification of warning signs in Malaysian patients having COVID-19 infection who progress to severe form of the illness.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is an infectious disease caused by a novel coronavirus, now widely known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has caused 3 major pandemic waves in Malaysia. We aimed to identify the warning signs as indicators that predict the progression of disease. MATERIALS AND METHODS: This is a retrospective cohort study of adult patients more than 12 years of age presenting with laboratory-confirmed COVID-19 admitted in three separate hospitals around the country. RESULTS: Of the 228 patients initially admitted with mild illness, 47 had progressed requiring oxygen. The median time from admission to deterioration was 3 days (IQR 2 - 5). Age more than ≥50years old (median age = 42.5, IQR = 28.8 - 57.0), higher temperature (mean = 37.3, IQR 36.8 - 38.0), MEWS score >3 (9, 19.1%), Neutrophil-to-lymphocyte ratio (NLR) >3.13 , (18, 38.3%) C-reactive protein (CRP) >5. (12, 27.3%), multiple zonal involvement on the chest radiography on admission (2, IQR 1-3) were more common in the deteriorated group on admission. On multivariate analysis, multiple comorbidities (HR = 7.40, 95 percent CI 2.58-21.2, p0.001), presence of persistent fever (HR = 2.88, 95 percent CI 1.15 - 7.2, p = 0.024), MEWS scoring >3 (HR of 6.72 ;95 percent CI 2.81-16.0, p0.001) were associated with progression to severe illness. CONCLUSION: In our cohort, we found that several factors were associated with the severity of COVID19. Early detection of these factors could correctly identify patients who need more intensive monitoring, and early referral for ICU care.

The PanSurg-PREDICT Study: Endocrine Surgery During the COVID-19 Pandemic.

BACKGROUND: In the midst of the COVID-19 pandemic, patients have continued to present with endocrine (surgical) pathology in an environment depleted of resources. This study investigated how the pandemic affected endocrine surgery practice. METHODS: PanSurg-PREDICT is an international, multicentre, prospective, observational cohort study of emergency and elective surgical patients in secondary/tertiary care during the pandemic. PREDICT-Endocrine collected endocrine-specific data alongside demographics, COVID-19 and outcome data from 11-3-2020 to 13-9-2020. RESULTS: A total of 380 endocrine surgery patients (19 centres, 12 countries) were analysed (224 thyroidectomies, 116 parathyroidectomies, 40 adrenalectomies). Ninety-seven percent were elective, and 63% needed surgery within 4 weeks. Eight percent were initially deferred but had surgery during the pandemic; less than 1% percent was deferred for more than 6 months. Decision-making was affected by capacity, COVID-19 status or the pandemic in 17%, 5% and 7% of cases. Indication was cancer/worrying lesion in 61% of thyroidectomies and 73% of adrenalectomies and calcium 2.80 mmol/l or greater in 50% of parathyroidectomies. COVID-19 status was unknown at presentation in 92% and remained unknown before surgery in 30%. Two-thirds were asked to self-isolate before surgery. There was one COVID-19-related ICU admission and no mortalities. Consultant-delivered care occurred in a majority (anaesthetist 96%, primary surgeon 76%). Post-operative vocal cord check was reported in only 14% of neck endocrine operations. Both of these observations are likely to reflect modification of practice due to the pandemic. CONCLUSION: The COVID-19 pandemic has affected endocrine surgical decision-making, case mix and personnel delivering care. Significant variation was seen in COVID-19 risk mitigation measures. COVID-19-related complications were uncommon. This analysis demonstrates the safety of endocrine surgery during this pandemic.

Microbial contamination and its associations with major ions in shallow groundwater along coastal Tamil Nadu.

Microbes in groundwater play a key role in determining the drinking water quality of the water. The study aims to interpret the sources of microbes in groundwater and its relationship to geochemistry. The study was carried out by collecting groundwater samples and analyzed to obtain various cations and anions, where HCO3-, Cl- and NO3- found to be higher than permissible limits in few samples. Microbial analysis, like total coliform (TC), total viable counts (TVC), fecal coliforms (FC), Vibrio cholera (V. cholerae) and total Streptococci (T. streptococci) were analyzed, and the observations reveal that most of the samples were found to be above the permissible limits adopted by EU, BIS, WHO and USEPA standards. Correlation analysis shows good correlation between Mg2+-HCO3-, K+-NO3-, TVC- V. cholerae and T. streptococci-FC. Major ions like Mg+, K+, NO3, Ca2+ and PO4 along with TS and FC were identified to control the geochemical and microbial activities in the region. The magnesium hardness in the groundwater is inferred to influence the TVC and V. cholerae. The mixing of effluents from different sources reflected the association of Cl with TC. Population of microbes T. streptococci and FC was mainly associated with Ca and Cl content in groundwater, depicting the role of electron acceptors and donors. The sources of the microbial population were observed with respect to the land use pattern and the spatial distribution of hydrogeochemical factors in the region. The study inferred that highest microbial activity in the observed in the residential areas, cultivated regions and around the landfill sites due to the leaching of sewage water and fertilizers runoff into groundwater. The concentrations of ions and microbes were found to be above the permissible limits of drinking water quality standards. This may lead to the deterioration in the health of particular coastal region.

P21-activated kinase 1 (Pak1) signaling influences therapeutic outcome in pancreatic cancer.

BACKGROUND: Therapeutic resistance to gemcitabine in pancreatic ductal adenocarcinoma (PDAC) is attributed to various cellular mechanisms and signaling molecules that influence as a single factor or in combination. DESIGN: In this study, utilizing in vitro p21-activated kinase 1 (Pak1) overexpression and knockdown cell line models along with in vivo athymic mouse tumor xenograft models and clinical samples, we demonstrate that Pak1 is a crucial signaling kinase in gemcitabine resistance. RESULTS: Pak1 kindles resistance via modulation of epithelial-mesenchymal transition and activation of pancreatic stellate cells. Our results from gemcitabine-resistant and -sensitive cell line models showed that elevated Pak1 kinase activity is required to confer gemcitabine resistance. This was substantiated by elevated levels of phosphorylated Pak1 and ribonucleotide reductase M1 levels in the majority of human PDAC tumors when compared with normal. Delineation of the signaling pathway revealed that Pak1 confers resistance to gemcitabine by preventing DNA damage, inhibiting apoptosis and regulating survival signals via NF-κB. Furthermore, we found that Pak1 is an upstream interacting substrate of transforming growth factor ß-activated kinase 1-a molecule implicated in gemcitabine resistance. Molecular mechanistic studies revealed that gemcitabine docks with the active site of Pak1; furthermore, gemcitabine treatment induces Pak1 kinase activity both in vivo and in cell-free system. Finally, results from athymic mouse tumor models illustrated that Pak1 inhibition by IPA-3 enhances the cytotoxicity of gemcitabine and brings about pancreatic tumor regression. CONCLUSION: To our knowledge, this is the first study illustrating the mechanistic role of Pak1 in causing gemcitabine resistance via multiple signaling crosstalks, and hence Pak1-specific inhibitors will prove to be a better adjuvant with existing chemotherapy modality for PDAC.

Lithological and hydrochemical controls on distribution and speciation of uranium in groundwaters of hard-rock granitic aquifers of Madurai District, Tamil Nadu (India).

Uranium is a radioactive element normally present in hexavalent form as U(VI) in solution and elevated levels in drinking water cause health hazards. Representative groundwater samples were collected from different litho-units in this region and were analyzed for total U and major and minor ions. Results indicate that the highest U concentration (113 µg l(-1)) was found in granitic terrains of this region and about 10 % of the samples exceed the permissible limit for drinking water. Among different species of U in aqueous media, carbonate complexes [UO2(CO3)(2)(2-)] are found to be dominant. Groundwater with higher U has higher pCO2 values, indicating weathering by bicarbonate ions resulting in preferential mobilization of U in groundwater. The major minerals uraninite and coffinite were found to be supersaturated and are likely to control the distribution of U in the study area. Nature of U in groundwater, the effects of lithology on hydrochemistry and factors controlling its distribution in hard rock aquifers of Madurai district are highlighted in this paper.

A multivariate statistical approach to identify the spatio-temporal variation of geochemical process in a hard rock aquifer.

A study has been carried out in crystalline hard rock aquifers of Madurai district, Tamil Nadu, to identify the spatial and temporal variations and to understand sources responsible for hydrogeochemical processes in the region. Totally, 216 samples were collected for four seasons [premonsoon (PRM), southwest monsoon (SWM), northeast monsoon (NWM), and postmonsoon (POM)]. The Na and K ions are attributed from weathering of feldspars in charnockite and fissile hornblende gneiss. The results also indicate that monsoon leaches the U ions in the groundwater and later it is reflected in the (222)Rn levels also. The statistical relationship on the temporal data reflects the fact that Ca, Mg, Na, Cl, HCO3, and SO4 form the spinal species, which are the chief ions playing the significant role in the geochemistry of the region. The factor loadings of the temporal data reveal the fact that the predominant factor is anthropogenic process and followed by natural weathering and U dissolution. The spatial analysis of the temporal data reveals that weathering is prominent in the NW part and that of distribution of U and (222)Rn along the NE part of the study area. This is also reflected in the cluster analysis, and it is understood that lithology, land use pattern, lineaments, and groundwater flow direction determine the spatial variation of these ions with respect to season.

Comparison of galvanic corrosion potential of metal injection molded brackets to that of conventional metal brackets with nickel-titanium and copper nickel-titanium archwire combinations.

AIM: The aim of the study is to investigate the galvanic corrosion potential of metal injection molding (MIM) brackets to that of conventional brackets under similar in vitro conditions with nickel-titanium and copper nickel-titanium archwires. MATERIALS AND METHODS: Twenty-five maxillary premolar MIM stainless steel brackets and 25 conventional stainless steel brackets and archwires, 0.16 inch, each 10 mm length, 25 nickeltitanium wires, 25 copper nickel-titanium wires were used. They were divided into four groups which had five samples each. Combination of MIM bracket with copper nickel-titanium wire, MIM bracket with nickel-titanium wire and conventional stainless steel brackets with copper nickel-titanium wire and conventional stainless steel brackets with nickel-titanium wires which later were suspended in 350 ml of 1 M lactic acid solution media. Galvanic corrosion potential of four groups were analyzed under similar in vitro conditions. Precorrosion and postcorrosion elemental composition of MIM and conventional stainless steel bracket by scanning electron microscope (SEM) with energy dispersive spectroscope (EDS) was done. RESULTS: MIM bracket showed decreased corrosion susceptibility than conventional bracket with copper nickeltitanium wire. Both MIM and conventional bracket showed similar corrosion resistance potential in association with nickel-titanium archwires. It seems that both brackets are more compatible with copper nickel-titanium archwires regarding the decrease in the consequences of galvanic reaction. The EDS analysis showed that the MIM brackets with copper nickel-titanium wires released less metal ions than conventional bracket with copper nickeltitanium wires. CONCLUSION: MIM brackets showed decreased corrosion susceptibility, copper nickel-titanium archwires are compatible with both the brackets than nickel-titanium archwires. CLINICAL SIGNIFICANCE: Clinically MIM and conventional brackets behaved more or less similarly in terms of corrosion resistance. In order to decrease the corrosion potential of MIM brackets, more precise manufacturing technique should be improved to get a more smoother surface finish.

Flowable composite an alternative orthodontic bonding adhesive: an in vitro study.

OBJECTIVE: To determine the clinical applicability of Ormocer based fowable adhesive (Admira fow) in comparison with BisGMA based adhesive (Transbond XT) and Ormocer based packable adhesive (Admira). MATERIALS AND METHODS: Sixty human premolars, divided into group I (n = 20) Transbond XT, group II (n = 20) Admira and group III (n = 20) Admira fow were bonded with metal brackets using adhesives. Brackets were debonded in shear on an Instron universal testing machine with a crosshead speed of 1 mm per minute. The mode of bond failure was determined by modifed ARI index. RESULTS: The results obtained from SBS evaluation and modifed ARI showed highest shear bond strength for Transbond XT (SD 11.64) 3.68 followed by Admira fow (SD 11.0) 2.87 and least for Admira (SD 9.42) 2.21. However, the difference was not statistically signifcant, but an intergroup comparison done using Independent student 't' test, showed statically signifcant difference between Transbond XT and Admira. Kaplan-Meier survival analysis showed least survival median value for Admira, but the survival median value is not statistically signifcant among the three groups. All groups had modifed ARI score of three (60-70%), suggestive of cohesive type of failure. CONCLUSION: The in vitro study showed that fowable Ormocer can be an good alternative to commonly used BisGMA based adhesive but the its effcacy needs clinical assessment through a survival analysis. CLINICAL SIGNIFCANCE: Admire fow can defnitely be considered as an alternative bonding system due to their comparable bond strength and debonding characters and reported properties of biocompatibility.

Assessment of metals distribution and microbial contamination at selected lake waters in and around Miri City, East Malaysia.

A baseline study was carried out to assess the metal concentrations and microbial contamination at selected Lake waters in and around Miri City, East Malaysia. Sixteen surface water samples were collected at specific Lakes in the environs of major settlement areas and recreational centers in Miri City. The Physico-chemical parameters [pH, Electrical Conductivity (EC) and Dissolved Oxygen (DO)], metals (Fe, Mn, Cu, Cd, Ni and Zn) and Escherichia coli (E. coli) were analysed. The concentrations of Fe, Mn and Ni have been found to be above the permissible limits of drinking water quality standards. The metals data have also been used for the calculation of heavy metal pollution index. Higher values of E. coli indicate microbial contamination in the Lake waters.

Adenoameloblastoma: a dilemma in diagnosis.

Adenoameloblastoma or adenomatoid odontogenic tumor (AOT) is an uncommon, benign, epithelial lesion of odontogenic origin. It is a rare benign odontogenic tumor of the jaw affecting mostly young individuals with predominance in female. It occurs mostly in maxillary anterior region. On the basis of clinical and radiographical picture, it is often misdiagnosed as an odontogenic cyst. We report on a rare case of a 13-year-old male patient with a follicular variety of AOT in mandibular left anterior region which is unusual for the same. Clinically and radiographically, the lesion was mimicking as a dentigerous cyst. Later surgical enucleation was done and specimen was sent for microscopic examination and was diagnosed as AOT along with a dentinoid-like deposits which is a rare finding.

Diagnosing Breast Cancer Based on the Adaptive Neuro-Fuzzy Inference System.

In this work, a novel hybrid neuro-fuzzy classifier (HNFC) technique is proposed for producing more accuracy in input data classification. The inputs are fuzzified using a generalized membership function. The fuzzification matrix helps to create connectivity between input pattern and degree of membership to various classes in the dataset. According to that, the classification process is performed for the input data. This novel method is applied for ten number of benchmark datasets. During preprocessing, the missing data is replaced with the mean value. Then, the statistical correlation is applied for selecting the important features from the dataset. After applying a data transformation technique, the values normalized. Initially, fuzzy logic has been applied for the input dataset; then, the neural network is applied to measure the performance. The result of the proposed method is evaluated with supervised classification techniques such as radial basis function neural network (RBFNN) and adaptive neuro-fuzzy inference system (ANFIS). Classifier performance is evaluated by measures like accuracy and error rate. From the investigation, the proposed approach provided 86.2% of classification accuracy for the breast cancer dataset compared to other two approaches.

Current overview for chemical disinfection of dental impressions and models based on its criteria of usage: A microbiological study.

Objectives: The aims of this study were to compare the efficacy of two proven chemical disinfectants, glutaraldehyde and povidone iodine on dental impression and models by determining the reduction in the microbial load, and to compare changes in the physical properties of the models after adding the disinfectants. Materials and Methods: Irreversible hydrocolloid upper impressions of 90 patients were made and divided into 3 groups of 30 samples each; Group A--Control group; Impressions were run under clean tap water before pouring the model. Group B--2% Glutaraldehyde sprayed on the impression and left in situ for 10 min before pouring the model. Group C -10 ml of (5%) povidone iodine incorporated into the gypsum before pouring the model. Models from all three groups were subjected to microbiological assessment at three different time intervals, T0--24 h, T1--1 month and T2--3 months of storage by comparing the colony forming units (CFUs) of bacteria and fungi. The compressive strength of 5 models from each group was also analyzed in Newton's/mm2. Results: 2% Glutaraldehyde proved more effective than povidone iodine after 24 h of storage (T1), however at the end of 1 month (T1) and 3 months (T2) the Povidone group showed the maximum disinfection. Both the disinfectants caused a reduction in the compressive strength of the model with the povidone iodine group showing the maximum reduction. Conclusion: Although povidone iodine was the most effective disinfectant after 3 months, it showed a significant reduction in the compressive strength and caused discoloration of the model. 2% Glutaraldehyde proved to be the choice of disinfectant with minimal adverse effects.

To block, or not to block is it still the question? Effectiveness of alpha- and beta-blockade in phaeochromocytoma surgery: an institutional analysis.

INTRODUCTION: Phaeochromocytomas/paraganglioma (PPGL) surgery was historically associated with significant risks of perioperative complications. The decreased mortality (<3.0%) had been attributed in part to optimal preoperative alpha-blockade. The value of alpha-blockade in decreasing morbidity is being challenged. The aim of our study is to present an institutional experience of preoperative alpha-blocking of PPGL and its effect on cardiovascular stability and postoperative morbidity. METHODS: A retrospective study using data from our institutional database was conducted. All patients undergoing adrenalectomy for PPGL from October 2011 to September 2020 were included. All patients were routinely alpha-blocked. Intraoperative cardiovascular instability (ICI) was assessed through number of systolic blood pressure (SBP) episodes >160mmHg, SBP <90mmHg, the need for vasoactive drugs and volume of intraoperative crystalloids administered. Morbidity was also evaluated. RESULTS: A total of 100 consecutive patients undergoing surgery were identified of whom 53 patients had complete anaesthetic records available for analysis. Thirty-two patients (60%) had at least one episode with an SBP >160mmHg. Nine (17%) cases had no intraoperative hypotensive episodes, while 3 (6%) patients had >10 intraoperative episodes of an SBP <90mmHg. Twenty-one (40%) patients received vasoactive drugs during surgery. The median volume of intraoperative crystalloids was 2 litres (1-4). Postoperatively, no patient experienced cardiovascular complications, including arrhythmia or myocardial ischaemia. Only two were admitted to an intensive care unit (ICU) and one 30-day readmission occurred. CONCLUSIONS: Cardiac instability remained significant in PPGL surgery despite optimal alpha- and beta-blockade. While omitting blockade would appear empirically questionable, a randomised controlled trial (RCT) of surgery with and without alpha-blockade will provide an answer.

To block, or not to block is it still the question? Effectiveness of alpha- and beta-blockade in phaeochromocytoma surgery: an institutional analysis.

INTRODUCTION: Phaeochromocytomas/paraganglioma (PPGL) surgery was historically associated with significant risks of perioperative complications. The decreased mortality (<3.0%) had been attributed in part to optimal preoperative alpha-blockade. The value of alpha-blockade in decreasing morbidity is being challenged. The aim of our study is to present an institutional experience of preoperative alpha-blocking of PPGL and its effect on cardiovascular stability and postoperative morbidity. METHODS: A retrospective study using data from our institutional database was conducted. All patients undergoing adrenalectomy for PPGL from October 2011 to September 2020 were included. All patients were routinely alpha-blocked. Intraoperative cardiovascular instability (ICI) was assessed through number of systolic blood pressure (SBP) episodes >160mmHg, SBP <90mmHg, the need for vasoactive drugs and volume of intraoperative crystalloids administered. Morbidity was also evaluated. RESULTS: A total of 100 consecutive patients undergoing surgery were identified of whom 53 patients had complete anaesthetic records available for analysis. Thirty-two patients (60%) had at least one episode with an SBP >160mmHg. Nine (17%) cases had no intraoperative hypotensive episodes, while 3 (6%) patients had >10 intraoperative episodes of an SBP <90mmHg. Twenty-one (40%) patients received vasoactive drugs during surgery. The median volume of intraoperative crystalloids was 2 litres (1-4). Postoperatively, no patient experienced cardiovascular complications, including arrhythmia or myocardial ischaemia. Only two were admitted to an intensive care unit (ICU) and one 30-day readmission occurred. CONCLUSIONS: Cardiac instability remained significant in PPGL surgery despite optimal alpha- and beta-blockade. While omitting blockade would appear empirically questionable, a randomised controlled trial (RCT) of surgery with and without alpha-blockade will provide an answer.

Environmental surface sampling of SARS-CoV-2 in selected hospitals in Malaysia.

COVID-19 has spread rapidly worldwide. The role of fomites in facilitating onward transmission is plausible. This study aimed to determine the presence of viable virus and its persistence on the surfaces of fomites in wards treating COVID-19 patients in Malaysia. This study was conducted in two stages. First, environmental sampling was performed on random days in the intensive care unit (ICU) and general wards. Then, in the second stage, samples were collected serially on alternate days for 7 days in two selected general wards. In Stage 1, a total of 104 samples were collected from the surfaces of highly touched and used areas by patients and healthcare workers. Only three samples were tested positive for SARS-COV-2. In Stage 2, three surface samples were detected positive, but no persistence of the virus was observed. However, none of the SARS-CoV-2 RNA was viable through tissue culture. Overall, the environmental contamination of SARS-CoV-2 was low in this hospital setting. Hospitals' strict infection control and the compliance of patients with wearing masks may have played a role in these findings, suggesting adherence to those measures to reduce occupational exposure of COVID-19 in hospital settings.

Study of evaluation of groundwater in Gadilam basin using hydrogeochemical and isotope data.

Gadilam river basin has gained its importance due to the presence of Neyveli Lignite open cast mines and other industrial complexes. It is also due to extensive depressurization of Cuddalore aquifer, and bore wells for New Veeranam Scheme are constructed downstream of the basin. Geochemical indicators of groundwater were used to identify the chemical processes that control hydrogeochemistry. Chemical parameters of groundwater such as pH, electrical conductivity, total dissolved solids, sodium (Na(+)), potassium (K(+)), calcium (Ca(+)), magnesium (Mg(+)), bicarbonate (HCO(-)(3)), sulfate (SO(-)(4)), phosphate (PO(-)(4)), and silica (H(4)SiO(4)) were determined. Interpretation of hydrogeochemical data suggests that leaching of ions followed by weathering and anthropogenic impact controls the chemistry of the groundwater. Isotopic study reveals that recharge from meteoric source in sedimentary terrain and rock-water interaction with significant evaporation prevails in hard rock region.