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Uranium concentration in the groundwater samples from the district of Tiruvannamalai, Tamil Nadu, was measured using an LED fluorimeter. Grid sampling technique was used for the collection of water in the study area. The basic physical parameters of water such as EC, TDS and pH were also determined and their levels have been compared with standard limits. All the samples qualified as potable water from the radiological perspective. Though some samples showed mild chemical toxicity they are still safe for ingestion. Different risk coefficients were calculated and they were compared with recommended safety limits specified by various agencies. Software tools such as QGIS 15 and Surfer 15 were employed for developing maps and plots.

The spatio-temporal distribution of geochemical fractions of phosphorus and its bio-availability for Asia's largest brackish water lake has been carried out. One way ANOVA analysis revealed that both iron bound phosphorus (Fe-P) (p central sector (42.22%) > outer channel (36.63%) > southern sector (29.27%) of total phosphorus (TP). This is supported by the fact that bioavailable P is comparatively higher in the freshwater zone than in the brackish water zone. The principal component analysis (PCA) revealed a good relationship between dissolved phosphate concentrations of water column with benthic population density. It showed that TP availability in the sediment of the lake is mostly bounded with Al, Fe and organic matter (OM). Positive association of total carbon (TC), total nitrogen (TN) and OM with negatively loading of Eh indicates towards the fact that, deposition of TN and TC is largely governed by OM availability in sediment.

The current study focuses on the vertical profile of different geochemical fractions of phosphorus - loosely bound (Lo–P), aluminium bound (Al–P), iron bound (Fe–P), calcium bound (Ca–P), and organic bound phosphorus (O–P) along with ecological risk assessment of sediment cores from Chilika Lake, east-coast of India. The percentage contribution of the different fractions to the sedimentary phosphorus in the sediment column of the whole lake are on the order: O–P (33.2%) > Ca–P (20.3%) > Fe–P (18%) > Al–P (6.7%) > Lo–P (0.35%). The Phosphorus Pollution Index (PPI) revealed the contamination of lake sediment with phosphorus. The principal component and cluster analyses highlighted the anthropogenic contribution of phosphorus. The negative loading of Ca–P with Ca points towards its origin from marine shells. The discriminate analysis showed that the variables like Ca–P, bio-available phosphorus (BAP), and pH were able to effectively discriminate the sectors in a significant manner.

The Chilika Lagoon is the largest brackish water ecosystem in the Asian continent and is a Ramsar site. Here, the sorption–desorption study was standardized simulating the environmental condition of the Chilika, to ascertain whether phosphorus (P) is the source or sink for sediments of the coastal ecosystem. The sorption behaviour of sediment phosphorus was better fitting into the modified Langmuir model. The effects of salinity, pH, and temperature on phosphorus sorption were found to be better understood by nonlinear relationships. The sorption was recorded to increase at its lower concentrations with increasing of mentioned parameters, when it decreased beyond some threshold values. The maximum phosphorus sorption capacity (Qmax) was more (258 mg/kg) in the freshwater stretch of the lagoon; Northern Sector compared to the relatively saline stretches, i.e., Outer Channel (219 mg/kg) and Southern Sector (237 mg/kg) (p

The study signifies the first work on natural radioactivity and to identify the associations as well as influence of geochemical properties on it. The determination of the natural radioactivity such as: 226Ra, 232Th, and 40K were carried out by gamma spectrometer and the median activities were found to be 26.27, 81.61, and 620.09 Bq kg−1, respectively. The geochemical parameters are pH, sand, silt, clay, organic carbon (OC), calcium carbonate (CaCO3), magnesium (Mg), potassium (K), calcium (Ca), sodium (Na), iron (Fe), phosphorus (P) and nitrogen (N) has been determined. The lagoon was mostly dominated by muddy-type sediment which is nearly 60% of the total sample and the high pH noticed in the NS (7.58) of Chilika, which is due to the presence of grass and weeds, by their photosynthesis process, which may cause the lake slighter alkaline. The high Fe concentration (2.53%) in the NS may be due to rapid relies of iron, whereas the enrichment of Ca in CS (1.02%) in the sediment may be from land runoff. The influence and relations between geochemical and natural radionuclides of the sediment were evaluated through geo-statistics, such as correlation matrices, factor analysis, and cluster analysis.

The study focuses on the spatial mapping of naturally occurring radionuclides along entire Tamil Nadu coast, which constitute nearly 30% of the east coast of India. In view of this, a total of 37 beach sediment samples are collected, and spectral measurement was carried out by High Purity Germanium detector. The average activity concentrations were found to be in the range of 34.33 ± 32.94 Bq kg−1 for 238U, 51.55 ± 40.39 Bq kg−1 for 238Th and 282.59 ± 84.45 Bq kg−1 for 40K. The contour maps showed the spatial distributions of each radionuclide and were drawn using the kriging method. Box-whisker plot shows the variation of activity concentrations of radionuclides, which follows the order 40K > 232Th > 238U in all the sediment samples. To understand the complex relationships among the radioactive variables and its environmental classifications, a multivariate statistical technique such as correlation matrices, and cluster analysis were applied to the radioactive data sets.

This study focuses on the ecological health assessment of Chilika, a shallow lagoon present in east coast of India, through nutrient stoichiometry and trophic state index (TSI). Multivariate statistical analysis such as ANOVA, Pearson's correlation, Principal Component Analysis (PCA), and Discriminant Analysis (DA) were employed for data interpretation. Nutrient stoichiometry revealed that the Chilika Lagoon experiences phosphorus limitation with regard to nitrogen and silicate (N:P:Si = 16:1:16) throughout the study period. As per the computed TSI values, the southern sector (SS), central sector (CS), and outer channel (OC) were assigned with a mesotrophic status, whereas the northern sector (NS) was assigned with the eutrophic status. From PCA, total nitrogen was found to be negatively correlated with salinity and positively correlated with silicate, thus indicating that the major source of nitrogen in the lagoon was freshwater ingress by rivers with high silicate content. DA indicated that it was successful in discriminating the groups as predicted.

Socioeconomic developments and industrialization exert tremendous impact on beaches which is often neglected. Heavy metal (Cr, Mn, Co, Ni, Cu, Zn, Cd, and Pb) contents were estimated in the intertidal region from Kalpakkam to Mamallapuram (20 km), southeast coast of India covering seven locations. To evaluate the level of contamination of these metals; enrichment factor (EF), geoaccumulation index (I geo), contamination factor (CF), pollution load index (PLI) and modified degree of contamination (mCd) were applied. The results were also compared with the sediment quality guidelines (SQGs) to find out the eco-toxicity level. Metal contents in the beach sediment were observed in the order: Fe > Al > Mn > Cr > Cu > Ni > Zn > Pb > Co > Cd. Grain size distribution showed medium to coarse nature of the sediment. Significant positive correlation was found among the metals indicating their common source of input. Based on EF, minor enrichment of Mn and Zn and moderately severe to severe enrichment of Cr, Cu, Pb and Cd were observed which was further confirmed by I geo and CF values. Moreover, Mamallapuram showed a very high CF value for Cd (>6) indicating very high contamination accountable to anthropogenic sources. PLI and mCd in all the stations indicated unpolluted nature except M1 where the values pointed moderate degree of contamination. As per the SQGs, Ni and Cr values exceeded the probable effect limit value implying that these metals can have adverse impacts. None of the metals exceeded the effect range median indicating that the beach sediment is not very toxic.

This study focused on ecosystem responses to the environmental perturbations caused by the 2004 Indian Ocean Tsunami in a small lake that was a freshwater body in 1996, prior to the tsunami. The physicochemical and biological characteristics of Kokilamedu Lake (KKM) revealed drastic changes, compared with pretsunami conditions. Monthly average observations on water quality indicated the electrical conductivity of the water increased steeply to 17.41 mS cm−1 in 2009, from the lowest pretsunami value of 1.83 mS cm−1 (range of 1.83–5.25 mS cm−1). Simultaneously, the nitrate + nitrite (NO3 + NO2) values increased significantly from 0.49 μmol L−1 in 1996 to 74.47 μmol L−1 in 2006. Silicate (SiO4-Si) exhibited a dramatic increase in concentration, from an average of 64.87 μmol L−1 in the pretsunami period to 309.71 μmol L−1 the post-tsunami period (2009–2010). Inorganic phosphate had increased to a maximum of 9.59 μmol L−1 from a pretsunami maximum of 1.09 μmol L−1. The chlorophyll-α concentrations did not respond to the increased nutrient stoichiometry of the lake. There was a decreased chlorophyll-α concentration under post-tsunami conditions. The recent infilling of the lake with sediment during the tsunami, associated with wind-driven resuspension reduced the light penetration. There was a significant improvement in dissolved oxygen concentrations (2006–2010 average of 8.27 mg L−1) in the lake, however, compared with the pretsunami values (1994–1995 average of 5.94 mg L−1). The algal component is now dominated by blue-green algae, while green algae had dominated in the pretsunami period. Pre- and post-tsunami observations from a control site did not exhibit such dramatic shifts from the 1995 and 1996 conditions, whereas a shift was apparent in the case of KKM. Certain marine fishes have adapted to this altered ecosystem. These marine species encountered (Elops machnata, Cociella punctata, Sphyraena jello, Platycephalus indicus, Glossogobius giuris) might have been recruited during the intrusion of the tsunami waves.

Sequential chemical extractions were used to study the spatial and temporal distribution of different forms of phosphorus (P) in the surface sediments of Chilika, the largest brackish water lake in Indian subcontinent. Sediments were analyzed for different forms of phosphorus along with some sedimentary parameters such as sand, mud, and organic carbon. The lake sediments are found to be mostly sandy near outer channel, whereas other parts of the lake are muddy sand type. Among the inorganic phosphorous fractions, calcium-bound P (Ca-P) emerged as the most dominant fraction contributing 55 and 37 % of the total phosphorous (TP) respectively in pre- and post-monsoon seasons, respectively. Contribution of loosely bound phosphorus (Lo-P) to the TP in lake system was the lowest (

Formation character of brominated-trihalomethanes (Br-THMs) in chlorinated seawater and its dependence on applied chlorine dose, reaction time, and temperature were investigated in the laboratory. Seawater was collected from the east coast of India and a chlorine dose of 1, 3, 5, and 10 ppm was each applied at a temperature of 20, 30, and 40 degrees C to investigate the yield and kinetics of Br-THMs formation. Qualitative and quantitative estimation of THM formation at various intervals of time ranging from 5 min to 168 h was determined by a gas chromatograph equipped with an electron capture detector (GC-ECD). Chlorine dose, chlorine contact time, and reaction temperature positively affected the load of THMs. The ratio of chlorine dose to halogen incorporation decreased from 12% to 5% with increasing applied chlorine dose from 1 to 10 ppm. Significant levels of THMs were found to be formed within 0.5 h of reaction, followed by a very slow rate of formation. Elevated temperature favored both increased rate of formation and overall THM yield. The formation order of different trihalomethane species at all studied temperatures was observed to be bromodichloromethane (CHCl2Br) < dibromochloromethane (CHClBr2) < bromoform (CHBr3). Formation of chloroform was not observed, and bromoform was the dominant (96% to 98%) among the three THM species formed.

MOHANTY, P.K.; PATRA, S.K.; BRAMHA, S.; SETH, B.; PRADHAN, U.; BEHERA, B.; MISHRA, P., and PANDA, U.S., 2012. Impact of groins on beach morphology: a case study near Gopalpur Port, east coast of India. Gopalpur Port is being developed as an all-weather open seaport from a fair-weather port which has existed since 1987. Two groins, a 530-m south groin and a 370-m north groin, were constructed during the periods from August 2007 to November 2009 and October 2007 to September 2008, respectively, on the north and south of the 500-m jetty which existed earlier. Port authorities are planning to construct a southern breakwater and a series of seven northern groins. Therefore, it is essential to assess the impacts of coastal structures on beach morphology and shoreline change in the present context and to predict future trends. To achieve this, a long-term observational programme has been conducted since May 2008. Observations include beach profile, shoreline change (berm position), littoral environment ...

The geochemical association of some trace metals (Fe, Mn, Ni, Cu, Cr, and Pb) were sequentially extracted from bulk sediments of the Chilika lagoon, India. The low elemental concentration, except Pb, in the exchangeable phase suggests poor availability to bottom dwellers. However, slightly higher abundance of Pb in the exchangeable phase at station 4 (9.9%) and station 6 (9.5%) is mainly related with waste from major fishing jetties. The carbonate-bound phase reflects heavy metal distribution of detrital origin along with biological decomposition in the lagoon. A relatively higher percentage of Mn in the reducible phase is attributed to the flocculation of its colloids. The concentrations of Cu, Ni, and Pb show their higher affinity to the organic-bound fraction. The absolute metal concentrations in the residual fraction was Fe > Mn > Ni > Cu > Pb > Cr, which reflects the predominance of physical weathering, a high erosion rate, and a high sedimentation rate in the lagoon. According to Risk Asses...

The distribution of hydrological characteristics like temperature, pH, salinity, conductivity, DO, BOD, alkalinity, nutrients (NO 2 -N, NO 3 -N, PO 4 -P, SiO 4 -Si) along with depth, transparency and turbidity were studied in Chilika, the largest brackish water lagoon in Asia. The results exhibited pronounced spatial variation and distribution pattern, indicating large variations, possibly due to seasonal changes. The photosynthesis of weeds caused the lake water slightly alkaline due to uptake of CO 2 from water column and on the other hand, the formation of humic acid because of decaying of weeds in northern sector lowers the pH of the lake water. The low salinity in northern sector related to influx of more floodwater, which was not very much affected in southern sector. Addition and removal of fresh water, seawater intrusion and mixing bring out the change in salinity of the lagoon. The low DO and high BOD values were associated with the area near to large fishing jetties, where organic decomposition was more. Nitrite exhibited higher concentrations during May due to its release into the water column from the decomposed freshwater weeds. High nitrate during July and August were related to agricultural runoff through floodwater. Silicate concentration showed a well-defined pattern with higher during monsoon months, which was slightly removed at high salinities areas.

A study was carried out at Kalpakkam coast to find out the distribution of various fractions of phosphorus (P) in the marine sediment during pre-northeast monsoon period. Samples were collected from ten locations covering ~80 km2 of the inner-shelf region. Sedimentary parameters such as sand, silt, clay, and organic carbon percentage were analyzed in order to find out their relation with various P fractions. The sediment was found to be predominantly sandy in nature with low silt and clay content. Among all the fractions (loosely bound (LoP), calcium bound (CaP), iron bound (FeP), aluminum bound (AlP), and organic (OP)), CaP fraction constituted the largest portion (68.7 %) followed by organic fraction (16.3 %). The bioavailable P fractions ranged from 5 to 44 % of the total P (TP) content. Relatively high LoP content was observed at the offshore locations with comparatively high mud percentage as compared with the near-shore locations. As FeP and AlP concentrations were directly proportional to the amount of fine-grain sediment, the low levels of these fractions found in this coastal area were therefore attributed to the sandy nature of the sediments. The order of abundance of the major forms of P in the surface sediments of Kalpakkam coast was as follows: CaP > OP > LoP > AlP > FeP.

In the present study, concentration of some selected trace metals (Fe, Mn, Ni, Co, Pb, Zn, Cu, Cr and Cd) are measured in Brahmani, Baitarani river complex along with Dhamara estuary and its near shore. Chemical partitioning has been made to establish association of metals into different geochemical phases. The exchangeable fraction is having high environmental risk among non-lithogeneous phases due to greater potential for mobility into pore water. The metals with highest bio-availability being Cd, Zn and Cr. The metals like Mn, Zn, Cd and Cu represent an appreciable portion in carbonate phase. Fe-Mn oxides act as efficient scavenger for most of the metals playing a prime role in controlling their fate and transport. Among non-lithogeneous phases apart from reducible, Cr showed a significant enrichment in organic phase. Risk assessment code values indicate that all metals except Fe fall under medium-risk zone. In estuarine zone Cd, Zn, Pb and Cr are released to 32.43, 26.10, 21.81 and 20 %, respectively, indicating their significant bio-availability pose high ecological risk. A quantitative approach has been made through the use of different risk indices like enrichment factor, geo-accumulation index and pollution load index. Factor analysis indicates that in riverine zone, Fe-Mn oxides/hydroxides seem to play an important role in scavenging metals, in estuarine zone, organic precipitation and adsorption to the fine silt and clay particles while in coastal zone, co-precipitation with Fe could be the mechanism for the same. Canonical discriminant function indicates that it is highly successful in discriminating the groups as predicted.

The spatial distribution of natural radioactivity due to uranium, thorium and potassium was investigated in soils from the undisturbed areas in Yelagiri Hills, Tamilnadu, India by Isodose map. The radiological hazards due to natural radionuclides content such as representative level index (RLI), activity utilization index (AUI), excess lifetime cancer risk (ELCR) and internal radiation hazards ( H in ) of the soil samples in this area were calculated. The calculated radiological hazard parameters are compared with different countries of the world. The calculated range of ELCR is 0.326 × 10 −3 to 1.067 × 10 −3 with an average of 0.700 × 10 −3 for soils. This average value of ELCR is more twice than the world average (0.290 × 10 −3 ). A correlation analysis was made between measured dose rate and individual radionuclides, in order to delineate the contribution of the respective nuclides toward the dose rate. The U/Th concentration ratio in surface soil samples ranged from 0.05 to 1.72 with an average of 0.43 which is more higher (80%) than the world average of 0.26. The application of cluster analysis (CA) and principal component analysis (PCA), coupled with Pearson correlation coefficient analysis, were utilized to analyze the data, identify and clarify between the radiological parameters to know the existing relations. The CA and PCA results showed that the former method yielded three distinctive groups of the soil variables whereas the latter one yielded the number of variables into two factors with 94.47% variance explanation.