Application of GIS and DRASTIC Modeling for Evaluation of Groundwater Vulnerability near a Solid Waste Disposal Site

The study aims at evaluating the groundwater vulnerability to contamination in the vicinity of a solid waste disposal site, Njelianparamba, a municipal dumping site in Kozhikode, Kerala, India, using DRASTIC model using Geographic Information System environment. Vulnerability maps are intended to show areas of most potential to groundwater contamination on the basis of hydrogeological conditions and human impacts. The DRASTIC model consists of seven hydrogeological parameters that affect groundwater quality. The ESRI GIS software, Arc Map 10.1 was used to create the groundwater vulnerability map by overlaying the seven layers. The resulting vulnerability map was then validated using chemical and bacteriological analysis of samples collected from nearby wells of the dumping site to assess the area which is of more potential risk to pollution. According to the vulnerability map, the study area was divided into three vulnerability classes ranging between a minimum value of 120 and a maximum value of 243. The vulnerability classes are moderate vulnerable, high vulnerable and very high vulnerable. The vulnerability map revealed that the eastern and south eastern portion of Njelianparamba dump site was very highly vulnerable to groundwater contamination. This is probably due to the lower sloped terrains towards the eastern portion which allows percolation of contaminants into the groundwater.

Geospatial and Statistical Assessment of Groundwater Contamination Due to Landfill Leachate—A Case Study

This study was conducted to measure the impact of a municipal solid waste landfill on groundwater quality around Njelianparamba, a solid waste dumping site in Kozhikode district, Kerala state, India. One of the major problems associated with dumping of municipal solid waste landfill is the release of leachate and its impact on surrounding groundwater. In this study, physico-chemical and bacteriological parameters of groundwater samples collected from the region surrounding the leachate area during the pre- and post-monsoon seasons were analysed. The majority of the groundwater samples contained contaminants at a level beyond the permissible limit set by the Bureau of Indian Standards for drinking water quality. The Geographic Information System software of the Environmental Systems Research Institute, (USA) ArcMap 10.1 was used to prepare spatial distribution maps of different parameters and Leachate Pollution Index and Water Quality Index in the study area were applied to assess the overall quality of groundwater. Characterisation of leachate and groundwater samples revealed that, water in the domestic wells has been deteriorated in response to the percolation of leachate. Additionally spatial and correlation analysis revealed that contamination was present maximum within 300 m radius around the landfill site.

Defluoridation of water using biosorbents

Contamination of drinking water due to fluoride is a severe health hazard problem. Excess of fluoride (>1.5 mg/l) in drinking water is harmful to human health. Various treatment technologies for removing fluoride from groundwater have been investigated. The present study showed that Vetiveria zizanioides, a herbal plant of Kerala—commonly known as Vetiver is an effective adsorbent for the removal of fluoride from aqueous solution. Phosphoric acid activated Vetiver root showed good adsorption capacity than the fresh powdered Vetiver root. Batch sorptive defluoridation was conducted under variable experimental conditions such as pH, agitation time, dose of adsorbent and particle size. Maximum defluoridation was achieved at pH 6;there is a greater possibility of columbic interaction between fluoride ion and adsorbent surface at this pH. The percentage of fluoride removal in- creases with adsorbent dose and time at a given initial solute concentration. The surface and sorption characteristics were analyzed using SEM techniques. Freundlich as well as Langmuir isotherm were plotted and kinetic constants were determined.

Biotic Stress Induced Biochemical and Isozyme Variations in Ginger and Tomato by <i>Ralstonia solanacearum</i>

This unique study evaluates the effects of Ralstonia solanacearum (Rs) induced biotic stress in two cultivars, Zingiber officinale (ginger) and Lycopersicon esculentum (tomato). They were grown in pots and hydroponic systems with controls;to induce biotic stress, about 8 × 104 colony forming units of Rs suspension was injected into the healthy test plants. Upon induction of Rs stress, highly significant (p 0.01) biochemical changes (%) were noticed in respect to controls: carbohydrate content was generally high in both plants;while they showed decreased starch and protein contents;phenolics showed a swing of decrease or increase between pot and hydroponic systems;and all plants in general showed higher (3-6 fold) proline content upon induction of biotic stress. Regarding oxidative stress isozymes (OSE), superoxide dismutase (EC 1.15.1.1) isozymes were normally 3, but treated hydroponics had 4 with comparable relative mobility values;peroxidase (EC 1.11.1.7) isozymes were generally 2, except for treated hydroponic tomato. Briefly, Rs induced biotic stress caused wilt symptoms in ginger, but did not affect tomato though its biochemical and OSE patterns especially in those grown as hydroponics were elicited to significantly higher levels.

Sediment Quality Assessment of Kavvayi Wetland in South Coast India with Special Reference to Phosphate Fractionation and Heavy Metal Contamination

Sediments play an important role in elemental cycling in the aquatic environment;it can be sensitive indicator for monitoring contaminants in aquatic environments. The heavy metal prominence, the amount and different forms of phosphorous present in the surface sediments of Kavvayi Wetland, which is in the south west coast of India was studied and reported in this paper. A total number of 10 surface sediment samples were taken from various regions of Kavvayi Lake and were subjected to heavy metal analysis and also phosphorous fractionation. Phosphorous forms in the sediment samples were determined by the modified sequential extraction procedure and among the inorganic phosphorous pool;Fe and Al bound phosphorous constituted the major portion while the Ca-bound phosphorous constituted the minor part only. Higher concentration of organic phosphorous was also detected in all the samples. The sediment samples were analyzed for heavy metals such as Fe, Mn, Cu, Pb, Cd, Ni, and Zn and the results showed comparatively higher concentration than the background values. The degree of contamination for each station was determined. Sediment pollution load index (PLI) values of the studied area ranged from 0.39 to 2.55 which indicated that the wetland sediments were polluted. Multivariate statistical techniques were applied to evaluate and characterize the analytical data. Spatial distribution maps of phosphorous fractions and heavy metals would help to identify the pollution sources and vulnerable sites.

Sanitation Mapping of Groundwater Contamination in a Rural Village of India

Availability of clean water and adequate sanitation facilities are of prime importance for limiting diarrheal diseases. We examined the spatial information on the groundwater quality and sanitation facilities of a village in southern India using Geographic Information System (GIS) tools. Place of residence, position of wells and latrines were mapped and well water samples were tested for microbial contamination (Total Coliform Counts (TCC), Fecal Coliform Counts (FCC) and Fecal Streptococcal Counts (FSC)). A well structured questionnaire was administered to 50 residents of the selected areas to elicit information on water collection, handling and storage. The location and distances of wells from latrines were determined using the Global Positioning System (GPS) device and a tape rule respectively. Data on 170 cases of various water-borne diseases were collected from primary health centers in the study area. Groundwater in the village was found to be microbiologically unfit for consumption. Analysis using direct observations supplemented by GIS maps revealed poor planning, design of the wells and improper siting of wells from latrines which were found to be the possible reasons of groundwater contamination. There was a significant difference in TCC between covered and uncovered wells (p < 0.01) but no significant differences were observed in the FCC, FSC and well covering. The mean distance (6.44 ± 2.37 m) of wells from the latrines in the study area was below the limit (15.24 m or 50 ft) set by United State Environmental Protection Agency (USEPA). TCC and FCC increased with a decrease in distance between the wells and latrines with a significance (p < 0.01). A moderate negative correlation (r = -0.593, r = -0.470) was ensued between the distance from latrine and coliform count. This study accentuates the need to set standards for the siting of wells from latrines and need for treatment.

<i>Ralstonia solanacearum</i>Induction Causes Biochemical and Oxidative Stress Isozyme Variations in Mangroves without Wilt

We evaluated the effects of Ralstonia solanacearum (Rs) induced biotic stress in three mangroves, viz., Avicennia officinalis, Derris trifoliata and Excoecaria agallocha. These plants were grown in pots as well as hydroponic systems with sufficient controls, and about 8 × 104 colony forming units of Rs suspension was injected into the healthy test plants (saplings). The plants were subjected to biochemical and isozyme analyses. Upon induction of Rs stress, highly significant (p 0.01) biochemical changes (%) were noticed in respect to controls: carbohydrate content was generally high (24-36) in all plants;hydroponic mangroves showed higher starch content, mangroves under hydroponic system showed increased reducing sugars (29-46), almost all mangroves showed increased protein content;phenolics showed a swing of decrease or increase between plants grown in pot and hydroponic systems;and all plants in general showed higher proline content. Regarding oxidative stress isozymes (OSE) and superoxide dismutase (EC1.15.1.1), mangroves showed 1 or 2 additional isozymes with comparable relative mobility;similarly 1 or 2 additional peroxidase (EC1.11.1.7) isozymes were found in mangroves grown under hydroponic system. Briefly, Rs induced biotic stress did not cause any wilt symptom in all the 3 mangroves tested, but their normal biochemical and OSE patterns, especially of those grown as hydroponics were elicited to significantly higher levels.

Assessment of Water Quality Status of Guruvayur Municipality

Groundwater is an essential and vital component of our life support system. The deterioration in the groundwater quality due to geogenic and anthropogenic activities has drawn great attention as it is the major alternate source of domestic and drinking water supply. Groundwater and surface water samples collected from various locations in Guruvayur were analysed for selected physico-chemical and bacteriological parameters by adopting APHA standard methods. The results of the analysis indicated the chemical and bacteriological contamination due to the disposal of solid, organic and septic wastes in the surface water samples of Chakkamkandam, Palayur and Edappally which are the various locations in Gurauvayur. Also the groundwater samples of Guruvayur were contaminated. The study revealed that, the water samples examined were found to be above the permissible limits of Bureau of Indian Standards (BIS). The sewage inlets that open directly to the water body are the major source of pollutants. The monitoring of various water bodies indicates the importance of taking appropriate measures to treat the water resources before either discharged to wetlands or consumed by human beings. It is also recommended to continue the monitoring periodically to assess the pollution status of the area.

Remediation of Endosulfan by Biotic and Abiotic Methods

Endosulfan is a persistent, toxic broad-spectrum organochlorine insecticide and acaricide used on food and non-food crops. To overcome the problem of hydrophobicity of endosulfan, surfactants play a major role in soil remediation. A concentration of 1 g/L tween 80 released 83.89% ± 1.22% of endosulfan from the soil in 24 hours and a total of only 13.96% ± 0.14% was found remaining in the soil. Phytoremediation is an emerging technology that promises effective and inexpensive cleanup of contaminated hazardous waste sites. The potential of aquatic plant species Salvinia molesta and the terrestrial plant species, Spinach (Spinacia oleracea) and Tomato (Solanum lycopersicum), to remove persistent organochlorine pesticide endosulfan from contaminated water and soil respectively were investigated. Remediation of endosulfan in water using different aquatic plants showed that Salvinia molesta is more efficient in endosulfan removal as the percentage removal of endosulfan obtained was 97.94% ± 0.33% in 21 days (with an initial concentration of 123 μg/L endosulfan). Among the selected terrestrial plant species, Spinach and Tomato, percentage removal of endosulfan was found to be higher with tomato. On Day 21, complete removal of pesticide (with an initial concentration of 140 μg/Kg endosulfan) occurred in the soil in which phytoremediation was done with tomato while spinach took about 28 days for complete removal of endosulfan. Microbial degradation offers an effective approach to remove toxicants from the environment. Microbial degradation of endosulfan was studied and Pseudomonas species was able to completely degrade endosulfan in 16 days. The technologies developed can be utilized for the complete removal of endosulfan from a contaminated area. The surfactant enhanced recovery and phytoremediation will help to decontaminate the polluted water and soil. The recovered endosulfan in the surfactants and plants can be subjected to biodegradation by bacterial species using a bio reactor.

Nano-Phytotechnological Remediation of Endosulfan Using Zero Valent Iron Nanoparticles

Endosulfan, an organochlorine pesticide, is known for its toxicity and ability to accumulate in the environment. In India endosulfan was banned only in 2011 and hence toxic residues are still persistent in the environment. The abilities of three plant species Chittaratha (Alpinia calcarata), Tulsi (Ocimum sanctum), and Lemongrass (Cymbopogon citratus) to remove endosulfan from soil in the absence and presence of zerovalent iron nanoparticles (nZVIs) (1000 mg/Kg of soil), i.e., by phytoremediation and nano-phytoremediation, were determined. Extracted soil samples from the experimental plot were analyzed using Gas Chromatograph with Electron Capture Detector (GC-ECD) and final dehalogenated product was confirmed by Mass Spectrometer (MS). A. calcarata had the best efficiency compared to the other two plant species and the efficiency decreased in the order A. calcarata > O. sanctum> C. citrates. The initial endosulfan removal rate was high (82% was removed within 7 days) when nano phytoremediation experiments were conducted with A. calcarata but then gradually decreased, probably because the activity of nZVI decreased over time. The nZVI endosulfan degradation mechanism appears to involve hydrogenolysis and sequential dehalogenation which was confirmed by GC-MS analysis. Only small amounts of endosulfan were accumulated in the plants because the added nZVIs might have promoted the reductive dechlorination of endosulfan.

Hydro-hypsometric analysis of tropical river basins,Southwest Coast of India using geospatial technology

The key aspect in planning and management of water resources is to analyze the runoff potential and erosion status of the river basin.For the detailed investigation of hydrological response freely available Cartosat-1(IRS-P5) data was used for the preparation of digital elevation model(DEM).The runoff potential and type of erosive process of 22 river basins originating in the global biodiversity hotspot of Western Ghats,was inferred through hypsometric analysis.Several parameters like Hypsometric integral(HI),maximum concavity(Eh),coordinates of slope inflection point(I) given by a* and h* and normalized height of hypsometric curve(h) were extracted from the hypsometric curves and used for understanding the hydrological responses.From the hypsometric curves,the landform evolution processes were inferred.Contribution of diffusive and fluvial processes in slope degradation of the river basins was understood.Basins with lesser area(<100 km^2) were found to have a positive correlation between hypsometric integral and basin area,whereas for large basins no such correlation exists.Based on the study,river basins can be prioritized for the appropriate conservation measures.

Changes in Streamflow Regime Due to Anthropogenic Regulations in the Humid Tropical Western Ghats, Kerala State, India

Regulation of streamflow by a reservoir creates a flow regime much different from the preimpoundment period flow regime. Hydro-Electric Projects(HEPs) commissioned in the Western Ghat regions of the Kerala State, India during the last four decades caused considerable changes in the flow regimes of the rivers of the Kerala State in southwest India. In this paper, the Indicators of Hydrologic Alteration(IHA) approach proposed by Richter et al.(1996) is used to analyze flow regime changes in the Periyar and Muvattupuzha Rivers, due to the construction of the Idukki(1976), Idamalayar(1987) and Lower Periyar(1997) HEPs in the high ranges of the Western Ghats. Normal rainfall years(annual rainfall values within mean ± 0.75 standard deviation limits) are only considered in the analysis to focus on hydrologic alterations due to human activities. The mean hydrologic alteration in the Periyar River(deviation from the pre-development hydrologic indicator values) after commissioning of three HEPs is 35%. Inter-basin water transfer after power generation from the Idukki HEP resulted in a higher discharge in the adjacent Muvattupuzha River, leading to considerable changes in the hydroenvironment(mean hydrologic alterations varying between 57 to 63%). IHA parameters showing hydrologic alterations above the 67 th Percentile werefurther analyzed. For each of the pre-construction hydrologic parameters ± 1 standard deviation from the mean is set as the upper and lower management target limits. The values of each IHA parameter beyond these targets are considered as nonattainment. Considerable hydrologic alterations are observed, especially for low flows in both basins. Inter-basin transfer induced larger changes in flow parameters compared to intra-basin regulations. The study shows that under a proper water release and diversion scheme, the non-attainment of IHA parameters(values fall beyond the target limits) can be reduced. The findings of the study will be greatly beneficial to regional water management and restoration of an eco-environmental system in the humid tropical region.

Morphometric analysis of the drainage system and its hydrological implications in the rain shadow regions, Kerala, India

The rain shadow regions requisite a comprehensive watershed development and management plan for sustainable water resources management. The Pambar River Basin （PRB） lies on the rain shadow region of the southern Western Ghats, India, where climate showed marked intra-basin variation. A morphometric analysis was done to evaluate the drainage characteristics of PRB using topographical maps and digital elevation data. PRB was divided into eighteen 4th order basins （SB1-SB18）, distributed along various climatic gradients. Lower order streams mostly dominate PRB and drainage pattern is a function of relief and structure. The terrain is highly dissected and prone to soil erosion during heavy storms and the elongated shape of PRB enables easier flood management. The influence of climate on drainage characteristics was evidently emphasized in basin morphometry. Four distinctively different classes were identified based on the morphometric similarities. The significance of morphometric analysis on the hydrological characterization is discussed and the relevance of the present study in water harvesting has been explicated.

Geospatial approach to elucidate anomalies in the hierarchical organization of drainage network in Kuttiyadi River Basin, Southern India

An assessment of anomalies in the hierarchical organization of the drainage network in the Kuttiyadi River Basin(KuRB),Kerala,has been performed by considering various morphometric parameters such as bifurcation index(R),hierarchical anomaly index(Δa),hierarchical anomaly density(ga),and stream gradient index(SL)in a geographical information system(GIS)platform.Further,a digital elevation model(DEM)of the area has been generated from Cartosat stereo pair data at 2.5-m resolution.The computed quantitative information about drainage characteristics reveals the highest drainage anomaly is observed in sub-watersheds(SW)III and IV.It is observed that neo-tectonic activity caused the development of younger stage drainage patterns of structural controls in the sub-watersheds of this river basin.The tectonic activityinduced diffusion,high energy fluvial erosion,and anthropogenic interferences altered the hierarchical organization of the drainage network of the sub-watersheds in mature to old stages of geomorphic evolution.The results of finding validated with asymmetry factor and ratio of the hierarchical index(Δa)with hierarchical anomaly number(A),bifurcation index(R),direct bifurcation ratio(Rdb),stream gradient index(SL),and denudation index(logTu).From the denudation index analysis,the sediment yield of the river basin is identified as 0.67 t·km^(−2)·yr^(−1).Moreover,the asymmetric factor(AF)in the KuRB shows the imprints of Paleo−Neo Proterozoic crustal tilting toward a NNW−SSE direction.