Post-monsoon Samples Research Articles

Distribution of environmental tritium in rivers, groundwater, mine water and precipitation in Goa, India

Tritium concentration in rivers, groundwater, precipitation and mine pits water, all over Goa state was characterized to find out spatial and temporal variability of tritium. Twenty four water samples were collected during pre-monsoon and post-monsoon and analyzed for their tritium concentration. The mean tritium concentration in surface and sub-surface hydrosphere is 2.5 (±0.6) TU. The mean concentration of tritium in rivers, groundwater, mines pits water and rain water are 2.9 (±0.5) TU, 1.95 (±0.5) TU, 2.5(±0.3) TU and 3.1(±0.1) TU respectively. The tritium distribution in all the samples shows modern precipitation (post-1950) component in surface and sub-surface hydrosphere of Goa. The HYSPLIT4.0 air mass trajectory model and atmospheric circulation pattern suggest that the moisture origin was from the Arabian Sea and this low tritium moisture is diluting the tritium concentration of surface hydrosphere near the coastal area. The tritium concentration in surface hydrosphere shows more and more enrichment as one move inland (i.e. away from the coast). Significant seasonal change is observed in the surface hydrosphere. The pre-monsoon samples showed higher tritium concentration than post-monsoon samples. This may be due to high rate of re-evaporation of water and a reduction in the supply of oceanic moisture during the summer (pre-monsoon).

Groundwater quality assessment of urban Bengaluru using multivariate statistical techniques

Groundwater quality deterioration due to anthropogenic activities has become a subject of prime concern. The objective of the study was to assess the spatial and temporal variations in groundwater quality and to identify the sources in the western half of the Bengaluru city using multivariate statistical techniques. Water quality index rating was calculated for pre and post monsoon seasons to quantify overall water quality for human consumption. The post-monsoon samples show signs of poor quality in drinking purpose compared to pre-monsoon. Cluster analysis (CA), principal component analysis (PCA) and discriminant analysis (DA) were applied to the groundwater quality data measured on 14 parameters from 67 sites distributed across the city. Hierarchical cluster analysis (CA) grouped the 67 sampling stations into two groups, cluster 1 having high pollution and cluster 2 having lesser pollution. Discriminant analysis (DA) was applied to delineate the most meaningful parameters accounting for temporal and spatial variations in groundwater quality of the study area. Temporal DA identified pH as the most important parameter, which discriminates between water quality in the pre-monsoon and post-monsoon seasons and accounts for 72% seasonal assignation of cases. Spatial DA identified Mg, Cl and NO3 as the three most important parameters discriminating between two clusters and accounting for 89% spatial assignation of cases. Principal component analysis was applied to the dataset obtained from the two clusters, which evolved three factors in each cluster, explaining 85.4 and 84% of the total variance, respectively. Varifactors obtained from principal component analysis showed that groundwater quality variation is mainly explained by dissolution of minerals from rock water interactions in the aquifer, effect of anthropogenic activities and ion exchange processes in water.

Assessment of potentially toxic trace elements contamination in groundwater resources of the coal mining area of the Korba Coalfield, Central India

Exploiting coal by open-cast mining often poses a threat to groundwater chemistry due to leachate of contaminants from the mine drainage water. In order to assess this, groundwater, river water and mine water samples were collected from Korba Coalfield and analysed for potentially toxic trace elements (PTEs) along with in situ parameters. Thereby, an integrated approach of pollution evaluation indices [heavy metal pollution index (HPI), heavy metal evaluation index (HEI) and contamination index (C d)] and statistical techniques are applied to the results. Paired-sample t tests reveal that the PTE concentrations of the pre-monsoon samples are higher than those of the post-monsoon samples. At a few locations, the concentration of Fe (56%), As (56%), Al (26%), Mn (19%) in pre-monsoon and Mn (46%), Ni (15%), Ba (15%), Pb (8%) in post-monsoon seasons exceeds the acceptable limit of Indian drinking standards. However, HPI values are below the critical pollution index value of 100 in both seasons in spite of an excess of these elements. The pollution indices evaluated by the multiple of the mean values approach reveal that 100, 94, 87% of the pre-monsoon and 92, 92, 85% of the post-monsoon samples belong to the “low-to-medium” category with respect to the HPI, HEI and C d indices. The thematic map depicting the spatial distribution of the contamination index (C d) testifies the role of a “dilution effect” that results in lower pollution loads in the post-monsoon samples than the pre-monsoon ones. The results of cluster analysis confirm that the quality of the water is mainly controlled by geogenic processes and anthropogenic inputs, besides dilution effects.

Dengue seroprevalence, seroconversion and risk factors in Dhaka, Bangladesh.

BackgroundDengue virus (DENV) activity has been reported in Dhaka, Bangladesh since the early 1960s with the greatest burden of dengue fever and dengue hemorrhagic fever cases observed in 2000. Since this time, the intensity of dengue activity has varied from year to year, and its determining factors remained relatively unknown. In light of such gaps in knowledge, the main objectives of this study were to determine the magnitude of seroprevalence and seroconversion among the surveyed population, and establish the individual/household level risk factors for the presence of DENV antibodies among all age groups of target populations in the city of Dhaka.Methodology/Principal findingsConsidering the lack of fine scale investigations on the factors driving dengue activity in Bangladesh, a prospective cohort study involving serological surveys was undertaken with participant interviews and blood donation across the city of Dhaka in 2012. Study participants were recruited from 12 of 90 wards and blood samples were collected during both the pre-monsoon (n = 1125) and post-monsoon (n = 600) seasons of 2012. The findings revealed that the seroprevalence in all pre-monsoon samples was 80.0% (900/1125) while the seropositivity in the pre-monsoon samples that had paired post-monsoon samples was 83.3% (503/600). Of the 97 paired samples that were negative at the pre-monsoon time point, 56 were positive at the post-monsoon time point. This resulted in a seroprevalence of 93.2% (559/600) among individuals tested during the post-monsoon period. Seroprevalence trended higher with age with children exhibiting a lower seropositivity as compared to adults. Results from this study also indicated that DENV strains were the only flaviviruses circulating in Dhaka in 2012. A multivariate analysis revealed that age, possession of indoor potted plants, and types of mosquito control measures were significant factors associated with DENV seroprevalence; while attendance in public/mass gatherings, and use of mosquito control measures were significantly associated with DENV seroconversion after adjusting for all other variables.Conclusions/SignificanceOur study suggests that there is a high level of endemic dengue virus circulation in the city of Dhaka which has resulted in significant DENV seroprevalence among its residents. Seropositivity increased with age, however, a substantial proportion of children are at risk for DENV infections. Our serological analysis also documents considerable DENV seroconversion among study participants which indicates that a large proportion of the population in the city of Dhaka were newly exposed to DENV during the study period (pre-and post-monsoon 2012). High levels of seroconversion suggest that there was an intense circulation of DENV in 2012 and this may have resulted in a significant risk for viral associated illness. Findings of our study further indicated that home-based interventions, such as removing indoor potted plants and increased bed net use, in addition to vector control measures in public parks, would reduce exposure to DENV and further decrease risk of viral associated disease.

THE USE OF Ipomoea Pes-Caprae PLANT SPECIES TO MONITOR METAL POLLUTIONS OF THE COASTAL SOIL

In this study, biomonitoring technique was applied to evaluate metals pollution at selected beach site. Ipomoea pes-caprae species were used to monitor the concentration level of lead (Pb), aluminum (Al), iron (Fe), barium (Ba), and zinc (Zn). Besides studying the ability and effectiveness of this plant as biological indicators of metal pollution in beach areas, the study also aimed to characterize the possible contributors of the metals in the area. The selected plants were collected along the coastal areas of Balok, in Kuantan, Pahang Malaysia. The study area is directly connected to the fish landing jetty of the local residents. The samples were collected at six sampling stations along the polluted shoreline area in two seasons, pre-monsoon and post-monsoon; and were duplicated. The metal content in the Ipomoea pes-caprae was considered as the indicator of environmental pollution in the coastal area. Significant differences of metal concentrations were found in samples collected from different sampling stations with certain levels. A comparison of the metal contents to the control samples clearly proved that the area has been polluted with the studied metals. In general, lower metals concentrations were found in post-monsoon samples compared to pre-monsoon samples. The concentration of metal Al was found to be the highest in the plant samples; The plant samples were contained the highest concentration of metal Al; followed by Fe, Zn, Ba, and Pb. Based on the EF values, it is strongly suggested that all the metals uptake were via the root system. The results of the PCA clearly indicated that the elements of Al, Fe, and Ba were contributed by the soil origin; meanwhile the elements of Pb and Zn were correlated to anthropogenic sources.

Rock magnetic finger-printing of soil from a coal-fired thermal power plant.

We present seasonal rock magnetic data for 48 surficial soil samples collected seasonally around a coal-fired thermal power plant on the southwest coast of India to demonstrate how fly ash from the power plant is transported both spatially and seasonally. Sampling was carried out during pre-monsoon (March), early-monsoon (June), monsoon (September) and post-monsoon (December) seasons. Low- and high-frequency magnetic susceptibility (χlf and χhf), frequency-dependent magnetic susceptibility (χfd), χfd %, isothermal remanent magnetization (IRM), "hard" IRM (HIRM), saturation IRM (SIRM) and inter-parametric ratios were determined for the samples. Scanning electron microscopy (SEM) was used on limited number of samples. NOAA HYSPLIT MODEL backward trajectory analysis and principal component analysis were carried out on the data. Fly ash samples exhibit an average HIRM value (400.07 × 10(-5) Am(2) kg(-1)) that is comparable to that of soil samples. The pre- and post-monsoon samples show a consistent reduction in the concentration of magnetically "hard" minerals with increasing distance from the power plant. These data suggest that fly ash has indeed been transported from the power plant to the sampling locations. Hence, HIRM may perhaps be used as a proxy for tracking fly ash from coal-fired thermal power plants. Seasonal data show that the distribution of fly ash to the surrounding areas is minimum during monsoons. They also point to the dominance of SP magnetite in early-monsoon season, whereas magnetic depletion is documented in the monsoon season. This seasonal difference is attributable to both pedogenesis and anthropogenic activity i.e. operation of the thermal power plant.

The Himalayan cryosphere: A critical assessment and evaluation of glacial melt fraction in the Bhagirathi basin

The cryosphere constitutes an important subset of the hydrosphere. The Himalayan cryosphere is a significant contributor to the hydrological budget of a large river system such as the Ganges. Basic data on the cryosphere in the Himalaya is inadequate and also has large uncertainties. The data on glacial melt component in the Himalayan rivers of India also shows high variability. The Gangotri glacier which constitutes nearly a fifth of the glacierized area of the Bhagirathi basin represents one of the fastest receding, large valley glaciers in the region which has been surveyed and monitored for over sixty years. The availability of measurement over a long period and relatively small glacier-fed basin for the Bhagirathi river provides suitable constraints for the measurement of the glacial melt fraction in a Himalayan river. Pre- and post-monsoon samples reveal a decreasing trend of depletion of δ18O in the river water from glacier snout (Gaumukh) to the confluence of the Bhagirathi river with the Alaknanda river near Devprayag. Calculations of existing glacial melt fraction (∼30% at Rishikesh) are not consistent with the reported glacial thinning rates. It is contended that the choice of unsuitable end-members in the three component mixing model causes the overestimation of glacial melt component in the river discharge. Careful selection of end members provides results (∼11% at Devprayag) that are consistent with the expected thinning rates.

Geochemical Appraisal of Fluoride Laden Groundwater in Suri I and II Blocks, Birbhum District, West Bengal

The present study has been carried out covering two blocks – Suri I and II in Birbhum district, West Bengal, India. The evaluation focuses on occurrence, distribution and geochemistry in twenty six water samples collected from bore wells spread across the entire study area homogeneously. Quantitative chemical analysis of groundwater samples collected from the present study area have shown that samples from two locations – Gangta and Dhalla contain fluoride greater than the permissible limit prescribed by WHO during both post monsoon and pre monsoon sampling sessions. Significant factor controlling geochemistry of groundwater has been identified to be rock – water interaction processes during both sampling sessions based on the results of Gibb’s Diagrams. Geochemical modeling studies have revealed that fluorite (CaF2) is indeed present as a significant fluoride bearing mineral in groundwaters of this study area. Calcite or CaCO3 is one of the most common mineral with which fluorite remains associated and saturation index calculations have revealed that the calcite – fluorite geochemistry is the dominant factor controlling fluoride concentration in this area during both post and pre monsoon. High fluoride waters have also been found to be of ‘bicarbonate’ type showing increase of sodium in water with decrease of calcium.

Assessment of bioavailable metals in the sediments of Yamuna flood plain using two different single extraction procedures

Abstract Though flood plains are considered as most fertile areas across the world but they have come under severe stress due to the flow of untreated domestic and industrial effluents and therefore, needed attention for its characterisation and subsequent treatment plans. The sediment samples, collected at 0–15, 15–35 and 30–60 cm depth levels during pre and post monsoon season from east and west sides of the river Yamuna around the national capital region of Delhi, were assessed for bioavailability of lead (Pb), zinc (Zn) and nickel (Ni) using Ethylene Diamine Tetra Acetic Acid (EDTA) and acetic acid. The average concentrations of Zn (25 ± 6 mg kg −1 ) and Pb (33 ± 6 mg kg −1 ) leached in EDTA were higher than that of in acetic acid (Zn: 22 ± 6 mg kg −1 ; Pb: 24 ± 5 mg kg −1 ) whereas Ni (24 ± 6 mg kg −1 ) leached more in acetic acid compared to EDTA (Ni: 21 ± 4 mg kg −1 ). The bioavailable concentrations of metals were comparable among 0–15 and 15–35 cm depth samples but decreased in 35–60 cm depth samples. The post monsoon samples contained lower amounts of total metals in comparison to pre-monsoon samples, an indication of washout/dilution effects of flood/high water flow during monsoon season. The percentages of metals, with reference to their respective total concentrations, in the flood plain sediments as extracted by EDTA were in the range of 14–47% for Pb, 17–54% for Zn, and 15–39% for Ni. The Zn, Ni and Pb were soluble in acetic acid in the range of 12–39%, 16.7–36.5% and 14–36%, respectively. The chemical nature of extracting agent affected the metal leaching. Acetic acid, a weak acid, extracted the metals that were present in exchangeable fraction and easily movable whereas EDTA, hexa-dentate complexing agent, extracted metals from carbonate and organically bound fractions of the sediment samples. This could result in metal accumulation in the floodplains, biomagnification, adverse effects on water quality, sediments, aquatic lives and the vegetables grown in the flood plains. Steps should be taken to stop the direct flow of untreated waste into the river to safeguard the floodplains and life forms.

Sources apportionment and spatio-temporal changes in metal pollution in surface and sub-surface soils of a mixed type industrial area in India

Metals in the urban soils of industrial townships adversely affect human health and ecosystem. In the present work, surface and sub-surface soils collected at 0–10cm and 10–20cm depth, respectively, in pre and post monsoon seasons from twenty sites in an urban industrial area adjoining New Delhi are studied for the total metal concentrations (Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) seasonal changes and pollution sources. Both surface and sub-surface soils are affected by high metal pollution with the contamination factor (CF)>2 and the average pollution load index (PLI) of 2.77. The geo-accumulation index values of 6.6–8.2 (pre and post monsoon samples) for Zn, 6.7–8.2 for Cr and 5.6–5.1 for Cd in surface soils indicate extreme levels of pollution in the region. A total four metal sources, industrial emissions for Fe, Mn, Cu, Ni, Co and Cd, electroplating industry for Zn and Cr, geogenic for Al and V, and vehicular and biomass burning for Ba and Pb in the surface soils were identified using the principal component analysis. Industrial emissions, explaining 46% of data variance, are the major source of metals. Surface soils around small scale industries are more polluted with Zn, Cr and Cd (CFs=25–31), and Cu and Pb (CFs=7–11) and have high PLI (range: 3.28–8.77) compared to other sampling sites. Higher geo-accumulation indices and pollution load of metals in the urban soils are expected to have long term impact on human health, plants and crop productivity in this area.

Assessment of heavy metal concentrations in surface water sources in an industrial region of central India

Rapid industrialisation and resulting industrial solid waste from power plants and integrated iron and steel industries, have imposed an enormous environmental pressure on water resources of Chhattisgarh, a state in Central India. Rural population living nearby the study area is mainly depended on the available surface water in the form of lakes or pond in their vicinity. Therefore it is necessary to look after the surface water through leachate pollution caused by dumping and disposal of industrial solid waste. In the present study, ten surface water samples each for pre monsoon and post monsoon were collected for analysis from the surrounding areas of a major industrial region of Chhattisgarh. The AAS analysis of the surface water samples shows higher concentration of certain heavy metals above the permissible limits. In the pre monsoon samples the metals Mn and Cr resulted higher concentration and at the same time metals; Cu, Fe and Pb resulted in lower concentrations. Similarly, for the post monsoon samples, Mn, Cr and Fe found with higher concentration, while Cu and Pb resulted with lower concentration. The high amount of heavy metals were found in the analyzed samples shows that there is a real risk for population living in the nearby areas of the industrial region of Chhattisgarh. Therefore a huge amount of industrial wastes produced needs a proper disposal. Unscientific and poorly-managed disposal of industrial solid wastes containing heavy metals needs remediation before discharging into the environment.

Distribution pattern of freshwater cyanobacteria in Kaiga region of Western Ghats of Karnataka

This study deals with the identification of 59 cyanobacterial species belonging to 27 genera from different freshwater habitats of Kaiga in Uttara Kannada district of Karnataka during the period from June 2009 to May 2011. Samplings were made during pre-monsoon; monsoon and post-monsoon sampling have been carried out for the duration of 2 years. The study deals with the occurrence of cyanobacterial species in five different aquatic habitats in Kaiga region, with respect to a change in the physico-chemical properties of water. The cyanobacterial diversity is maximum in monsoon season compared to post-monsoon; it was least during pre-monsoon. Among cyanobacteria non-heterocystous filamentous forms were dominant followed by unicellular forms, whereas heterocystous forms were least in number. It was also found that the physicho-chemical properties of water have the influence on the richness of cyanobacterial community. This study indicates the maximum occurrence and abundance of Chroococaceae (23.73%) and Phormidaceae (18.64%) members in all the sites, whereas Stigonemataceae (1.7%) shows very less occurrence. Among the cyanobacteria identified non-heterocystous filamentous forms were dominant followed by unicellular forms; whereas heterocystous forms were least in number.

Evidences of Manure Driven and C:N Regulated Enhanced Carbon Status and Microalgal Productivity in Managed Aquatic System under Simulated Green House Conditions

Groundwater is indispensible for continuity of life and sustainability of ecosystem. It is needed in almost every sphere of human activity. Hence, this study is aimed at assessing the ground water quality in Rajnagar block, Birbhum district, West Bengal, India, with respect to drinking and irrigation uses. A total of 17 groundwater samples each for both post- and pre-monsoon periods have been collected. The physical parameters pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS) have been determined in the field itself. The samples were analysed for cations like Ca, Mg, Na, K and anions like Cl, HCO3 and SO4. Overall, the groundwater in the study area is found to be slightly acidic to basic (pH ranging from 6.32 and 7.26 in pre-monsoon and 6.3 to 7.33 in post-monsoon) and moderately hard to very hard (Total Hardness ranging from 109.39 mg/L and 2328.43 mg/L in premonsoon and 60.6 mg/L and 969.79 mg/L in post-monsoon) in nature. Concentration of sulphate is above the maximum permissible limit in seven of the post-monsoon samples. Piper’s diagram indicates groundwater is mostly of bicarbonate type. Groundwater of the study area is moderately suitable for drinking. Water Quality Indices (WQI) indicates 75% of pre-monsoon samples are excellent to good for drinking purposes whereas the value reduces to 56% during postmonsoon. The calculated values of Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC) and Soluble Sodium Percentage (SSP) indicate well to permissible range of water for use in irrigation. Magnesium Adsorption Ratio (MAR) and RSC values at some sites limit use for agricultural purposes. Ground water chemistry is controlled by rockwater interaction as expressed by Gibb’s diagram.

Rock magnetic properties of lateritic soil profiles from southern India: Evidence for pedogenic processes

We report here data on the pH, electrical conductivity (EC) and environmental magnetic properties (χlf, χfd, χARM, IRMs at different field strengths) of modern tropical lateritic soils from Aribail, Miyapadavu and Uliyathadka, all in the Kasaragod District of Kerala, southern India. This study aims to characterize the rock magnetic properties of lateritic soils that formed under tropical high-rainfall conditions and determine the effects of pedogenesis on soil magnetic properties in comparison with temperate soils. The profiles may be divided into two or three zones based on differences in magnetic mineral concentration, grain size and mineralogy. There is no magnetic enhancement of topsoil in any of the profiles studied. As the lateritic rocks in the region are ferruginous, the lateritic soils developed over them contain significant amounts of coarse grained lithogenic magnetite as well as hematite. Because of the presence of this ‘laterite-derived’ magnetite and hematite, the lateritic soils have much higher susceptibility values when compared to temperate soils. The upper zone is characterized by a higher proportion of lithogenic grains and the lower zone by superparamagnetic (SP) grains. This is probably because of iron reduction and dissolution of fine magnetic grains at the profile-top because of the excessively high rainfall (average=~3500mm/year) in the region. The slight increase in χlf and SIRM values toward the top of the Aribail and Miyapadavu profiles is due to the presence of coarse magnetic grains. This characteristic is common to all the three profiles irrespective of the topography. Compared to pre-monsoon samples, post-monsoon samples exhibit an increase in the proportion of SP grains. However, the magnetic grain size of lateritic soils from the three locations is similar to that of temperate soils.

Geochemical modeling to evaluate the mangrove forest water

The knowledge about genetic origin of the chemi- cal elements is important for the evaluation of hydro- geochemistry of aquatic ecosystem. In the present study, pre- and post-monsoon samples were collected to identify the role of rain and seawater in the hydro-geochemical processes. Geochemical model and multivariate statistical methods of data analysis were jointly used to define the variations and the genetic origin of chemical parameters of water in man- grove ecosystem. The geochemical model, WATEQ4F, was executed to compute the saturation indices of the minerals with respect to surface water. The interpretation of the satura- tion indices for minerals shows that the majority of samples fall inthe categoryof under saturationstate exceptfor fluorite. An increase in the concentration of various nutrients, namely, nitrate and phosphate, was observed. Suitability of water was checked on the basis of chemical categorisationby Aquachem software. Grouping of waters on the Piper diagram suggested a common composition and origins. Further results showed that pre- and post-monsoon samples mainly consist of Na-Cl and Ca-Cl water type indicating a significant contribution of cations and anions from terrestrial and marine inputs in the mangrove ecosystem.

A Comparative Study of Ion Chemistry of Groundwater Samples of Typical Highland and Midland Sub-watersheds of the Manimala River Basin, Kerala, South India

Results of the detailed study of the chemistry of ions present in the groundwater samples of Peruvanthanam and Valiyathodu sub-watersheds of the Manimala river basin are analysed using the AQUACHEM 4.0 software to understand general chemical characteristics and geochemical processes involved. The study reveals that cations, such as sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+) and anions, such as bicarbonate (HCO3-), sulphate (SO42-), chloride (Cl-), nitrate (NO3-) are present. Recognition methods such as (a) Box and Whisker diagram (b) Piper diagram (c) Durov diagram (d) Radial plot and (e) Stiff diagram were prepared to delineate the seasonal variations in chemical constituents. The major ionic concentration of the groundwater samples of Peruvanthanam sub-watershed is Mg2+>Ca2+>HCO3->Cl->SO42->NO3->Na+>K+ and that of Valiyathodu is Mg2+>Ca2+>HCO3->Cl->NO3->SO42->Na+>K+. A critical analysis of Piper diagram reveals that in Peruvanthanam sub-watershed the pre monsoon groundwater samples belong to the zone of bicarbonates, chloride and sulphates, the monsoon season samples belong to the bicarbonate and chloride zone and the post monsoon samples belong to the zone of prevailing bicarbonates. In Valiyathodu sub-watershed, the pre monsoon and post monsoon samples have dominant bicarbonates, while the monsoon samples show predominance of both bicarbonates and chloride. Radial plots and Stiff diagrams for Peruvanthanam sub-watershed show that Mg2+-Ca2+-HCO3-, Mg2+-Ca2+-Cl- and Mg2+-Ca2+-HCO3-- Cl- are the dominant water types during the pre monsoon season. Mg2+-Ca2+-HCO3--Cl-, Mg2+-Ca2+-Cl-- HCO3- and Mg2+-Ca2+-HCO3--Cl--SO42- are dominant during the monsoon and Mg2+-Ca2+-HCO3- and Mg2+-Ca2+-HCO3--Cl- are the dominant water types during the post monsoon season. In Valiyathodu sub-watershed during the pre monsoon - Mg2+-Ca2+-HCO3--Cl- and Mg2+-Ca2+-HCO3-, during the monsoonm - Mg2+-Ca2+- HCO3--Cl-, Mg2+-Ca2+-Cl-- HCO3- and Ca2+-Mg2+-HCO3--Cl-, and during the post monsoon - Mg2+-Ca2+-HCO3--Cl- and Ca2+-Mg2+-HCO3--Cl- are the dominant water types. DOI: http://dx.doi.org/10.5755/j01.erem.66.4.4037

Fluoride contamination mapping of groundwater in Northern India integrated with geochemical indicators and GIS

There are many incidents of increasing fluoride concentrations observed in India's groundwater. In the present study, the fluoride content was chemically analysed and integrated with geochemical model WATEQ4F sampled from Allahabad district, Northern India, with other water quality parameters. Geospatial technique was employed to depict the spatial distribution of fluoride concentrations, over this plain, normalized with WHO (World Health Organization) and BIS (Bureau of Indian Standards) standards represented in the form of spatially interpolated maps. Hydro-geological conditions, such as weathering, geochemical reactions, alkaline nature of water, ion-exchange and high variability in temperature range, were taken into account in describing the geo or anthropogenic contributions to fluoride in groundwater. A large database of available ancillary information on related factors, such as soil properties, geological settings and climatic and topographical information, on a local scale, were also taken into account to rationalize the results. The analysis implies that post-monsoon samples have elevated concentration of fluoride compared with the pre-monsoon samples, with several zones found severely contaminated with fluoride as compared with the set standards in both seasons. The correlation analysis revealed a high correlation of fluoride, with fluorite mineral saturation index, followed by calcite and magnesite, indicating that these minerals could be used as geochemical indicators for fluoride contaminated areas.

Development of Water Quality Index (WQI) model for the groundwater in Tirupur district, South India

Groundwater quality of the Tiruppur district in Tamil Nadu was investigated in this study to develop a Water Quality Index (WQI) model. Hydrochemical parameters showed tremendous variation in certain location over the seasons. Ionic chemistry of groundwater suggested that textile industries and rock-water interaction are major threats to the water quality. Analysis of Na and Ca concentration indicates that direct as well as the inverse cation exchange controls the natural cation chemistry. NO3 concentration shows that the pre-monsoon samples were affected by the fertilizer usage in agricultural fields. Na-Cl type of the water was dominant throughout the study area except few locations. WQI showed that 55% of the pre-monsoon samples and the 47% of the post monsoon samples were classified as poor/very poor/unsuitable for drinking category. Leaching of the textile waste and their transport to the downstream was well observed during the post-monsoon season. The specific contribution of river Noyyal in the transport of the solutes to the discharge zones was proved by the hydrochemistry of the samples.

An appraisal of groundwater quality for drinking and irrigation purposes in southern part of Bathinda district of Punjab, northwest India

Groundwater is being used for drinking and irrigation purposes in the agricultural dominated Indian state of Punjab. Fifty-six groundwater samples were collected from Bathinda, a south-western district of Punjab, during the pre-monsoon (March 2010) and post-monsoon (October 2011) seasons. These samples were tested for major cations, anions and contaminants. Various classification systems were used to study the groundwater quality with respect to drinking as well as irrigation purposes. Total dissolved solids (TDS) and total hardness (TH) are generally used to determine the suitability of groundwater for drinking purpose. Considering TDS as a parameter, 54 and 57 % groundwater samples were found to be unsuitable for use during the pre- and post-monsoon seasons. A wide range of TH values were observed in the pre-monsoon and post-monsoon waters samples (mean 250 and 270 mgL−1). About 75 % of pre-monsoon and 79 % of post-monsoon samples exceeded the maximum permissible limit (MPL) of TH (150 mg L−1) proposed by WHO. In terms of contaminant ions, 40 % and 55 % of the pre- and post-monsoon water samples were unfit for drinking purposes w.r.t. fluoride (MPL 1.5 mg F L−1), 29 and 36 % were unfit w.r.t arsenic (MPL 10 μg L−1) and 33 and 45 % were unfit w.r.t nitrate (MPL 45 mg NO3 − L−1), respectively. To determine the suitability of groundwater of Bathinda for irrigation purpose, three classification systems proposed by different research workers were used. The parameters electrical conductivity (EC), sodium adsorption ratio, and residual sodium carbonate (RSC) were calculated on the basis of chemical data. Considering EC and RSC together, 32 % samples collected during pre-monsoon season were fit, 19 % were marginal and 49 % were unfit for use. However, during post-monsoon, samples fit for irrigation decreased to 17 % and samples unfit for irrigation increased to 70 %. Increases in the percentage of unfit samples for irrigation after monsoon indicates addition of salts along with the rain water percolated into the groundwater. The other two classification systems, i.e. US Salinity diagram and Wilcox diagram also showed the similar results.

Spatial and Seasonal Variation in Groundwater Quality in Parts of Cuddalore District, South India

An effort has been made to evaluate the groundwater quality in parts of Cuddalore district in Tamil Nadu. This study observed an alkaline nature of water for all the samples throughout the year. Classification of water based on TDS shows that majority of the samples were permissible for drinking. A wide range of values for hardness were exhibited by the groundwaters. However, pre-monsoon samples were much harder than the post-monsoon samples. Two distinct water types were present in the study area, samples from coastal areas found to have Na–Cl and the upper reaches showed a Ca–HCO3 type of water. Results suggest that the major processes controlling the groundwater chemistry are the seawater intrusion in the eastern coastal aquifers and the rock-water interaction in western part. Most of the samples exceeded the permissible limit of sodium percentage for irrigation purposes. Fluoride and nitrate concentration were below the permissible limits. Spatial distribution maps showed a clear gradation in the concentration of water quality parameters from the hilly terrains to the coastal areas. This study revealed that the groundwater quality at the eastern boundary of Cuddalore, Kurinjipetai, Parangipettai, Keerampalayam and Komaratchi Taluks were deteriorated by the seawater intrusion.