M.K. Samantara

Bio: M.K. Samantara is an academic researcher from Indira Gandhi Centre for Atomic Research. The author has contributed to research in topics: Bay & Zooplankton. The author has an hindex of 6, co-authored 14 publications receiving 112 citations.

Heavy metal content in the beach sediment with respect to contamination levels and sediment quality guidelines: a study at Kalpakkam coast, southeast coast of India

Abstract: 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.

Groundwater nitrate contamination and use of Cl/Br ratio for source appointment

Abstract: Source appointment for groundwater nitrate contamination is critical in prioritizing effective strategy for its mitigation Here, we assessed the use of Cl/Br ratio and statistical correlation of hydro-chemical parameters to identify the nitrate source to the groundwater A total of 228 samples from 19 domestic wells distributed throughout the study area were collected during June 2011–May 2012 and analyzed for various physicochemical parameters Study area was divided into three spatial zones based on demographic features, viz, northern, southern, and central part Nitrate concentration in 57 % of samples exceeded the prescribed safe limit for drinking stipulated by the World Health Organization (WHO) and Bureau of Indian standards (BIS) The central part of the study area showed elevated nitrate concentration ranging from below detection limit (BDL) to 2635 mg/l as NO3 − and demonstrated high attenuation within the immediate vicinity thereby restricting diffusion of the nitrate to the adjacent parts Resolution of correlation matrix as statistical indicator for nitrate contamination was poor Seventy-seven percent of samples with high nitrate concentration (>45 mg/l as NO3 −) showed strong association with high Cl/Br mass ratio (350–900), indicating mixing of sewage and septic tank effluents with groundwater as a primary source for the nitrate in the studied area Nitrate level during monsoon (BDL, 2299 mg/l as NO3 −), post-monsoon (BDL, 2635 mg/l as NO3 −), and pre-monsoon (05–2231 mg/l as NO3 −) indicated additional contribution of surface leaching to groundwater

Seasonality in the distribution of dinoflagellates with special reference to harmful algal species in tropical coastal environment, Bay of Bengal

Abstract: A study was carried out in the coastal waters of Kalpakkam, southeast coast of India, to find out the seasonal variation in dinoflagellate community struc- ture. Samples were collected for a period of 4 years during 2006-2010. During the study 69 species of di- noflagellates were encountered among which Ceratium furca and Prorocentrum micans were most common during all the seasons. Genus Ceratium was found to be the most diverse one with 23 species which was followed by genus Protoperidinium with 16 species. Of 69 species, 27 species were considered as dominant based on their abundance during pre-monsoon (PRM), monsoon (MON) and post-monsoon (POM) periods. Relatively high density and diversity of dinoflagellates were encountered during the PRM period as compared to the MON and POM periods. Abundance pattern of dinoflagellates for three seasons showed the following trend: PRM>POM>MON. Salinity showed a positive correlation with dinoflagellate community showing its importance in dinoflagellate growth and sustenance. Ammonia and phosphate developed negative correla- tion with dinoflagellate density indicating the utilization of these nutrients by the dinoflagellate community. The presence of three dinoflagellate associations, broadly representing the three seasons experienced at this loca- tion, was evident from the cluster analysis. The study revealed presence of 19 relatively abundant toxic/red tide forming dinoflagellate species in the coastal waters of Kalpakkam.

New record of an epizoic diatom, Pseudohimantidium pacificum on two species of copepods from the Indian Ocean

Abstract: Introduction Adhesion of micro-organisms to the exoskeleton of crustaceans especially copepods is a very unique phenomenon and moreover, the exoskeleton of crustaceans constitute a convenient shelter for a variety of micro-organisms such as, bacteria, microalgae, protozoans, fungi etc. This phenomenon of adhesion is known as ‘epibiosis’ and in this process of interaction, the micro-organisms are epibionts and the crustaceans are basibionts ref. As a result of epibiosis, host and epibiont have both negative as well as positive effects. The disadvantages, mainly for the basibionts, in this relation involve a decrease in fecundity, perturbation of locomotion, increasing susceptibility to predation, lesions and diseases, increasing energy demands and faster sinking rate. Positive effects, mainly for the epibionts, include transfer of epibionts to food and oxygen enriched region and also by fixing themselves to moving bodies; they can easily avoid predation. It was reported that transfer of basibionts cause increase in the rate of sustenance for epibionts. According to Wahl, higher intensity of water flow facilitates the excreta to disperse and also regulates the dispersion of epibionts, subsequently improving the gene flow of their population. Among photosynthetic micro-organisms as epibionts, mostly pinnate diatoms (mostly benthic forms) have been found growing on the body of copepods. The first report on epizoic diatoms was revealed by Giesbrecht from the Adriatic Sea and later it was reported from different regions of the world. Very few numbers of reports from the Indian Ocean have recorded bacteria and protozoans as epibionts on various hosts. However, in this report, we found Pseudohimantidium pacificum, an epizoic diatom, on two copepod hosts i.e. Corycaeus Dana (Order-Poicilostomatoida; Family-Corycaeidae) and Euterpina acutifrons Dana (OrderHarpacticoida; Family-Euterpinidae), which to the best of our knowledge is the first report from the Indian coast as well as Indian Ocean. Among different epizoic diatoms, P. pacificum is one of the important one and was confirmed from our sample by detailed morphological investigations. Though the study on this epibiont was not done with an objective, we came across this phenomenon during our regular zooplankton monitoring program.

Biological productivity of the Indian Ocean

Abstract: India has a long coast line of nearly 6,000 km with the Andaman and Nicobar Islands and the Laccadive Archipelago lying beyond her shores. The geographical position of India with the peninsular portion extending deep into the central part of the Indian Ocean gives her a locational advantage in marine fishing activities. At present though India contributes about 4096 of the fish landings of the Indian Ocean, when viewed against the world production of 76 million tannes oJ marine fish, her share is only 1.6 million tonnes represent ing less than 2%.

GIS-based evaluation of groundwater geochemistry and statistical determination of the fate of contaminants in shallow aquifers from different functional areas of Agra city, India: levels and spatial distributions

Abstract: The quality of groundwater is very important in Agra because groundwater is the main source of water for drinking, domestic, agricultural and industrial uses. A groundwater geochemistry study was conducted in Agra where 28 samples were collected from shallow aquifers in May 2016 from different sites. The aim of this research was to assess the quality of groundwater for drinking purposes in the study area. Arc-GIS has been used to prepare geographic information system-based spatial distribution maps of different major elements. The groundwater quality was analyzed for various physico-chemical parameters, major cations and anions and some trace metals. The observed values were compared with BIS and WHO standards. Statistical parameters such as the mean, median, standard deviation, skewness and kurtosis were used to analyze the hydrogeochemical characteristics of the groundwater. Correlation coefficient analysis and principal component analysis (PCA) were performed to identify the sources of the water constituents. Our results showed that most of the samples exceeded the acceptable limit for drinking water standards. The sequence of abundance of the main cations was generally Na+ > Ca2+ > Mg2+ > K+, while the anions in order of abundance were HCO3− > Cl− > SO42− and NO3− > F−. All of the trace metals were within the permissible limit except for iron and manganese. The hazard index value of 5.7 × 10−2 indicated that there was no potential health risk in the study area. Ca2+, Mg2+, Cl− and SO42− were the dominant hydrogeochemical facies in the majority of the groundwater samples. Most of the parameters such as TDS, Cl−, HCO3−, SO42−, NO3−, Ca2+, Mg2+, Na+, K+ and TH showed strong correlations with each other, which were due to natural processes such as weathering, exchangeable ions and reduction/oxidation, as well as anthropogenic activity around the study area. The water quality index indicated that the water quality was poor at 46.43% of the sampling sites, very poor at 28.57% of the sites and unsuitable for drinking purposes at 25% of the sampling sites. Gibbs diagrams suggested rock weathering as a major driving force for controlling the groundwater chemistry in the study area, along with evaporation as a minor influence.