Search

This research was carried out using the open-source database system along with the continuous air quality monitoring station results from global data sets during the COVID-19 pandemic lockdown in India and the global. Our purpose of this research is to study the improvement of air quality and human mortality rates in countries worldwide during the COVID-19 pandemic lockdown. Worldwide air quality data were collected from > 12,000 continuous air quality monitoring stations on six continents covering 1000 major cities from over 100 countries. Here, we discussed the implementation of the open-source data set of basic air pollutants such as PM 2.5, NO2, temperature, relative humidity, and Air Quality Index variation during the pre-lockdown and lockdown pandemic COVID-19 in India and described the global aspect. An average concentration of PM 2.5 (145.51 μg/m3), NO2 (21.64 μg/m3), and AQI index (55.58) continuously decreased. The variation of PM 2.5, NO2, normally shows more than 25 μg/m3 every year, but during the COVID-19 lockdown period (April 2020) continuously decreased below 20 μg/m3. Similarly, the AQI index and meteorological factors such as temperature, relative humidity, and wind speed variation decreased significantly in the many countries in the world. In Asian countries, air quality improved during the national lockdown especially in the most polluted cities globally such as Beijing, Delhi, and Nanjing and also in developed cities like Madrid, New York, Paris, Seoul, Sydney, Tokyo. Furthermore, the reduction of particulate matter was in about 46%, and other gaseous pollutants during the lockdown period were observed in a 54% reduction. We are witnessing pollution reductions which add significantly to improvements in air quality. This is due to the massive decrease in the use of fossil fuel, which in turn reduces production and traffic in general. People nowadays are now willing to see a comparatively healthier world with bleached skies and natural ecosystems. This research finding demonstrates potential safety benefits associated with improving air quality and mortality rates during the COVID-19 pandemic, resulting in decreases in mortality rates in India and around the world.

The present study focuses on the environmental radioactivity and multi-risk assessment of nearshore sediments as a source of marine pollution along the Bay of Bengal. The study examines the distribution of primordial radionuclides concentration using a Na(I)Tl detector-based gamma-ray spectrometer and Potentially Toxic Elements (PTE) through atomic adsorption analysis. Further, the data obtained and characterization radiological risks, ecological threats, and assessing the spatial distribution of toxic elements in nearshore sediments as a proxy for marine contamination. The active concentration of primordial radionuclides such as 238U, 232Th and 40K were found in ranged from ≤ 3 to 68 (11.4), ≤ 9.5 to 142.7 (41.2) and 85.2 to 603.4 (362) Bq kg-1. Results show that the concentration of the average radionuclides is less than suggested by UNSCEAR ranges. The concentration of potentially toxic elements (Fe, Cr, Ni, Pb and Zn) was higher in deeper water depth. This study exposes that the primary control of such elements is mud distribution. A decreasing order has been seen as follows by the ecological risk index of individual elements: Cu > Pb > Ni > Cr > Zn. The significant Pb, Cu and Zn concentration was polluted at most stations, possibly contributing the regional and terrestrial sources such as industrial activity, urban drainage, manufacturing, and farming. This research suggests that anthropogenic behaviours in nearby land are the source of the deposition of metals and radionuclides in coastal and marine sediments.

This paper employs widely used Water Quality Index (WQI), which synthesizes biological and physiochemical parameters into one single number that can be straightforwardly understood by decision makers and public. Rameswaram Island is one of the highly populated Islands of India, embraces with density of economically/ecologically important species and is most significantly located between Palk Bay and Gulf of Mannar. Water quality data obtained from 25 sampling sites around Rameshwaram Island between April 2011 and March 2012. The key parameters included for development of Water Quality Index were pH, temperature, turbidity, suspended solids, dissolved oxygen and biochemical oxygen demand using multiplicative water quality index. WQI lies in the “Good” category for all the seasons except summer, which falls under “Moderate”. Station 5B shows “Moderate” WQI in all the seasons because of the pilgrimage and tourism activities as well as the settlement at Rameswaram discharging municipal sewage. The use of the indices on a continuous basis provides long-term data which is helpful for decision making and management.

This study is performed to evaluate the potential sources and seasonal variation of atmospheric mercury (Hg) emissions from regional sources and other influences in India. To achieve this, using the gold amalgam technique with an automated continuous mercury vapour analyzer (TekranTM 2537B). To assess the total gaseous mercury in high altitude mountain peak station at Kodaikanal & coastal/urban air in Chennai region, the impact of changing weather conditions is also evaluated. To compare the past and recent reports of mercury at different locations in the world. The average total gaseous mercury value in Chennai is 4.68 ng/m3, which is higher as compared to Kodaikanal, where it is 1.53 ng/m3. The association between TGM with meteorological parameters in ambient air such as temperature, relative humidity, rainfall intensity, the direction of wind and velocity of was studied. The TGM concentration in India are compared with other nations, the TGM levels are similar to the east and Southeast Asian countries, and also Europe, Sub-Saharan Africa and North America are the averages and maximum concentration generally smaller. This research will help to establish more effective management approaches to mitigate the impacts of atmospheric mercury on the rural and urban environment.

A study of the inter-annual variability of the warming of the southeastern Arabian Sea (SEAS) during the spring transition months was carried out from 2013 to 2015 based on in situ data from moored buoys. An attempt was made to identify the roles of the different variables in the warming of the SEAS (e.g., net heat flux, advection, entrainment, and thickness of the barrier layer during the previous northeast monsoon season). The intense freshening of the SEAS (approximately 2 PSU) occurring in each December, together with the presence of a downwelling Rossby wave, supports the formation of a thick barrier layer during the northeast monsoon season. It is known that the barrier layer thickness, varying each year, plays a major role in the spring warming of the SEAS. Interestingly, an anomalously thick barrier layer occurred during the northeast monsoon season of 2012–2013. However, the highest sea surface temperature (31 °C) was recorded during the last week of April 2015, while the lowest sea surface temperature (29.7 °C) was recorded during the last week of May 2013. The mixed layer heat budget analysis during the spring transition months proved that the intense warming has been mainly supported by the net heat flux, not by other factors like advection and entrainment. The inter-annual variability analysis of the net heat flux and its components, averaged over a box region of the SEAS, showed a substantial latent heat flux release and a reduction in net shortwave radiation in 2013. Both factors contributed to the negative net heat flux. Strong breaks in the warming were also observed in May due to the entrainment of cold sub-surface waters. These events are associated with the cyclonic eddy persisting over the SEAS during the same time. The entrainment term, favoring the cooling, was stronger in 2015 than that in 2013 and 2014. The surface temperatures measured in 2013 were lower than those in 2014 and 2015 despite the presence of a thick barrier layer. The substantial decrease in net heat flux along with entrainment cooling has been identified as causes for this behavior.

To assess the textural variations and to elucidate the depositional processes along Kalpakkam-Mahabaliuram stretch, beach and seabed sediments were collected seasonally in 2010, i.e., January (Post-monsoon), May (Summer), August (Southwest monsoon) and October (Northeast monsoon). The samples were collected in a transect pattern viz. from beach, 200 m, 500 m and 1000 m into the sea from 12 stations, stretching from Sadras in the south to Mahabalipuram in the north, covering a coastal length of about 15 km. For textural characterization, the sediment samples were subjected to sieve analysis. Granulometrically, the sediments are coarse to fine grained, moderately to moderately well sorted, exhibiting positive and negative skewness. The shore normal variations in mean size show reduction in coarseness towards the sea. The apparent closeness in the mean of grain size statistics between beach and seabed is partly due to similarity in sediment source (eroding coastal plain) as well as the similarity in depositional processes. Kurtosis of beach and seabed sediment varies between very platykurtic to very leptokurtic implying that sediments, to an extent, have attained sorting in a high energy environment. For elucidation of depositional environment, sub-population analysis, bivariant plots (i.e., mean vs standard deviation, skewness vs mean, skewness vs standard deviation, skewness vs kurtosis, and kurtosis vs mean), and discriminant function analysis were carried out. The sediments along Kalpakkam-Mahabalipuram stretch reveal the dominance of beach and beach related processes, and influence of fluvial processes during deposition.

Plastic plays a major role in today’s human life; moreover, it becomes a part of our life, yet it is a most challenging threat for the freshwater ecosystems in the future. The present study identifies, characterizes, and quantifies the microplastics in groundwater samples around Perungudi and Kodungaiyur municipal solid waste dumpsites in South India. To evaluate and assess the microplastic abundance, characteristics (composite, size, colour, shape, and surface morphology), detection methods of plastic particles, and potential risk factors from the absorption of microplastic in groundwater. Further, the microplastic particle classification was performed using LB-340 Zoom Stereo Microscope with LED Illumination, ATR-FTIR fitted with SEM with EDX analyzer. The groundwater samples (n = 20) were found contaminated with microplastic particles in the range of 2–80 items/L with coloured particles, white (38%), black (27%), green (8%), red (18%), blue (6%), and yellow (2%). The polymer type was found to occur in the following order: nylon (70%), pellets (18%), foam (6%), fragments (3%), fibers/PVC (2%), and polythene (1%). In both sampling sites, 90% of microplastics are derived from the buried plastics and waste fragmentation which are predominantly of polypropylene (PP), polystyrene (PS). Micro and nano plastics abundance in groundwater is of paramount importance as it has a major impact on human health. This study throws light on the characteristics and quantification of the microplastics in groundwater that initiates further research by which microplastics enter into the environment.

In the current scenario, microplastic, as a contaminant, is becoming an ecological threat to the freshwater ecosystem. The present study attempted to determine the quality and quantity of microplastic contaminants in water and soil samples at Veeranam lake in Tamil Nadu, India. It is very important to mention that the Veeranam lake in Tamil Nadu, is a major urban water source of the capital district of Tamil Nadu. Using Van Veen grab-sampling equipment and trawl methods, the study detected the presence of microplastics in 28 sediment samples and 31 water samples from the collected samples. In addition to this, the density separation was performed with zinc chloride solution using the Sediment-Microplastic Isolation (SMI) unit. The quantum of total plastic particle present in surface water were in the range of 13–54 items/km2 with a mean value of 28 items/km2. In the case of sediment samples, the amount of total plastic particle was found in the range of 92–604 items/kg with a mean value of 309 items/kg. The abundance of microplastic particles in water and sediments in various shape, colour, and composition as in the order of nylons > polythene > fibres/PVC > fragments > foam > pellets; dominant colours as white > red > black > green > blue and yellow at the sampling sites. In term of percentage of contaminant distribution, the study found that the collected water and sediment samples deposited with polymer type of plastic particles were nylon (39%), polyethylene (23%), polystyrene (19%), polypropylene (15%), and polyvinyl chloride (4%). The research work is a baseline study for the proposed site of Veeranam lake for microplastics contamination.

Coastal lagoon ecosystems are vulnerable to eutrophication, which leads to the accumulation of nutrients from the surrounding watershed over the long term. However, there is a lack of information about methods that could accurate quantify this problem in rapidly developed countries. Therefore, various statistical methods such as cluster analysis (CA), principal component analysis (PCA), partial least square (PLS), principal component regression (PCR), and ordinary least squares regression (OLS) were used in this study to estimate total organic matter content in sediments (TOM) using other parameters such as temperature, dissolved oxygen (DO), pH, electrical conductivity (EC), nitrite (NO2), nitrate (NO3), biological oxygen demand (BOD), phosphate (PO4), total phosphorus (TP), salinity, and water depth along a 3-km transect in the Gomishan Lagoon (Iran). Results indicated that nutrient concentration and the dissolved oxygen gradient were the most significant parameters in the lagoon water quality heterogeneity. Additionally, anoxia at the bottom of the lagoon in sediments and re-suspension of the sediments were the main factors affecting internal nutrient loading. To validate the models, R2, RMSECV, and RPDCV were used. The PLS model was stronger than the other models. Also, classification analysis of the Gomishan Lagoon identified two hydrological zones: (i) a North Zone characterized by higher water exchange, higher dissolved oxygen and lower salinity and nutrients, and (ii) a Central and South Zone with high residence time, higher nutrient concentrations, lower dissolved oxygen, and higher salinity. A recommendation for the management of coastal lagoons, specifically the Gomishan Lagoon, to decrease or eliminate nutrient loadings is discussed and should be transferred to policy makers, the scientific community, and local inhabitants.

The Gorgan Rod River, located in northern Iran in Golestan Province, is the largest watershed in the province, which its water quality is affected by natural and anthropogenic changes. Water samples were taken between 1984 and 2008 from 18 sampling stations, along the Gorgan Rod River. Determination of non-principal and principal monitoring stations was carried out for the Gorgan Rod watershed, south-east of the Caspian Sea. Water quality parameters including EC, TDS, bicarbonate, carbonate, chloride, total hardness, calcium, potassium, sodium, sodium adsorption ratio, sulfate, pH, and magnesium were measured. The graphic representations obtained underline that (i) PCA (principal component analysis) is associated with the natural and anthropogenic changes in the different stations; and (ii) the locations of the different stations studied are consistent with their apparent features. The results indicated that water quality in Basir Abad, Agh Ghala, Haji Ghochan, and Bagh Salian stations was of the poorest among other stations because of anthropogenic effects. The best water quality was observed in Ramian, Araz Kose, Nawda, Pas Poshtah, Lezore, Glikesh, and Tangrah stations because there were no changes in land uses.

Pulicat lagoon is the semi enclosed and second largest brackish water body in tropical India. The morphology, water quality and biological productivity of the lagoon had being subjected to noteworthy changes over the years under the influence of natural as well as human interference. Recent research have revealed that the lagoon losses its biological integrity due to more sedimentation from rivers predominantly in monsoon seasons, lagoon mouth closure, overfishing, pollution from various phenomena such as usage of motor boats, sewage disposal and aquaculture farms. In this work, evaluation of the status of this lagoon in terms of its biological, physical and chemical importance, its flourishing inheritance, the threats to this ecosystem and the knowledge gaps with the recommendations towards protection of its declining biodiversity are discussed.

Shoreline defined as the physical interface of land and water is dynamic in nature and provides economic and social security to the coastal habitations. Tamil Nadu having a largest coastline i.e., approximately 1000 km faces multiple threats due to both natural and anthropogenic interventions as a result of disasters, rapid urbanization, industrialization, sand and coral mining etc. In the present study, an attempt was made to elucidate the accreting and eroding sites from multi temporal satellite images of Tamil Nadu coast (1978 to 2014) using geospatial techniques coupled with United States Geological Survey Digital Shoreline Analysis System (USGS DSAS). Rate of shoreline change were demarcated based on End Point Rate (EPR) and Linear Regression Rate-of-change (LRR). Wave characteristics and its pattern along Tamil Nadu coast were studied, since it plays a major role in configuration of the shoreline position. Prograding shorelines are noticed at Tuticorin, parts of Chennai, Vedaranyam etc. This study provides a synoptic outlook of the degree of potential threat to the coastal system, to prioritize actions and to develop suitable adaptation measures.

In the present study, the change in benthic community was identified in the coastal stretch from Ennore to Pulicat, total of 6 stations were identified to study benthic community. In order to understand the distribution of the benthic community structure with respect to macro fauna in the Buckingham canal benthic were collected from all the stations during high tide on Spring tide of each month from September 2004 to December 2005 from bed and bank. Higher nutrient concentration during summer coincides with high density of Polycheates and Molluscs and vice versa during monsoon season. Salinity is also an important factor for macro fauna distribution and growth. Salinity is high during pre-monsoon and summer which resulted in high production. From the Abundance and Biomass correlation it is inferred that Station 2 and 4 are grossly polluted. Stations 1, 3 and 5 are moderately polluted and Station 6 is less polluted.

The intention of this study was to appraise the spatial and temporal variations in the physico-chemical parameters of coastal waters of Rameswaram Island, Gulf of Mannar Marine Biosphere Reserve, south India, using multivariate statistical techniques, such as cluster analysis, factor analysis and principal component analysis. Spatio-temporal variations among the physico-chemical parameters are observed in the coastal waters of Gulf of Mannar, especially during northeast and post monsoon seasons. It is inferred that the high loadings of pH, temperature, suspended particulate matter, salinity, dissolved oxygen, biochemical oxygen demand, chlorophyll a, nutrient species of nitrogen and phosphorus strongly determine the discrimination of coastal water quality. Results highlight the important role of monsoonal variations to determine the coastal water quality around Rameswaram Island.

Wave climate of the nearshore region along Chennai, Southeastern coast of India was simulated using MIKE 21 Nearshore wave module (NSW). Assessment of longshore sediment transport between Pulicat and Ennore was carried out using LITPACK. Typical wave spectrums for the three seasons – pre-monsoon, monsoon and post-monsoon at 10 m and 4 m depths exhibit the sea condition during post-monsoon, swell condition during monsoon and the combined sea and swell condition during pre-monsoon. Simulation show reasonably good comparison with buoy data in terms of wave height with an underestimation of wave period and direction. The correlation coefficient for significant wave height is 0.42 and 0.82 during the transition period and non monsoon period respectively. The littoral drift assessment has given a clear picture on how the current speed and direction play a major role in sediment transport. Sediment transport of about 0.9 × 106 m3 towards north and 0.2 × 106 m3 towards south results with a net northerly littoral drift of 0.7 × 106 m3/annum.

Sediments from Kalpakkam in the southeast coast of India were analyzed to characterize heavy mineral distribution. The mineral deposits are fine-grained in nature, and temporal and spatial variations are observed in mineral deposits. Iron mineral peaks observed indicate that hematite is present in the samples. The abundance of iron-based minerals explains the occurrence of black grains in the beaches of Sadras and Kokillamedu. In the rest of the region, the mineral distribution is found to be poor and patchy. Uranium-based radioactive minerals are present in the study area, viz., Uranmicrolite, Dessauite, Dumontite, and Sedovite. The common light minerals are quartz and caminite and the heavy minerals that are not iron-rich are tungusite, charoite, glagolevite, mangazeite, falkmanite, augelite, and struvite. Heavy minerals concentrated in the intertidal tide zone show well-developed swash marks by their typical alignment during the process of swash and backwash. Caminite is formed due to the reaction of s...

Assessment of vulnerability is essential for identifying and recognizing the coastal livelihood, socio-economic and ecological security status. However, coastal vulnerability assessments require a complex dataset including human and socio-economic factors. In this study, we investigated coastal vulnerability index (CVI) to map the vulnerability of Tuticorin coast toward coastal erosion using remote sensing data and geographical information techniques based on a multi-indicator approach. Gulf of Mannar located along the southeast coast of India and declared as a marine national park with high ecological diversity faces threat due to anthropogenic interventions as a result of industrialization, sand and coral mining, etc. CVI highlights the vicinity where the physical effects may be the greatest. Beach width was considered as an additional parameter, since a large number of coastal habitations were present adjacent to the beach along the study area. Coastal erosion, slope and relative sea level rise are the major factors affecting the coastal vulnerability in Tuticorin. CVI scores were categorized into four classes, viz., low, moderate, high and very high risk. Out of 84-km coastal stretch, 15 % falls under high risk, 12 % moderate vulnerability and 73 % the low vulnerable category. This approach provides an insight to assess the vulnerability and the degree of potential threat to the coastal system in order to prioritize actions and to develop adaptation measures.

The study aims for the quantitative assessment of chlorophyll concentration and their distribution in the coastal waters of Kalpakkam (Tamil Nadu, India) using the normalised water leaving radiance from the OCEANSAT-2 Ocean Colour Monitor (OCM-2) with in situ chlorophyll concentration. The site specific regional algorithm is based on the sigmoid relationship of the band ratio (nLw490/nLw555) and generates a polynomial relation. The validation of chlorophyll concentration yields a high correlation (r2 = 0.92) with 21 independent in situ samples. The study demonstrated the application potential of OCM-2 in assessing the biological conditions of coastal waters. The chlorophyll distribution predominates towards north depending on the local climatic conditions.

Pulicat is India׳s second largest brackish water lagoon with its mouth opening in the Bay of Bengal. The dynamics of the tidal inlet at Pulicat has been reported in this study on the basis of long term analysis using satellite remote sensing aided with Geographical Information System (GIS) and berm crest data. In addition, the short term analysis was carried out using monthly in situ Global Positioning System (GPS) profiling and sediment grain size analysis. The study of the shoreline dynamics along the inlet using the Linear Imaging Self – Scanning Sensor (LISS) – III along with the Survey of India toposheet of 1954 reveals that the inlet once with a single mouth is divided into two, over the period of time with the southern mouth migrating towards north with an inconsistent migration pattern of the northern mouth. The overall extent of migration is found to be within 3 km. The outcome of the 25 year berm crest data starting from 1978 revealed the coastline around Pulicat is eroding upto 1990 and thereafter it is accreting with the net shoreline erosion rate of 20.34 m/yr. The monthly in situ beach profiling studies from August 2004 to July 2005 revealed that the Pulicat inlet follows a variable migratory pattern with a shift of upto 914 m North during August to December with a reversal migration of 600 m thus leading to a net migration towards the north. The grain size analysis has unravelled the sediment transport around Pulicat inlet. The study of the inlet using satellite imagery during monsoon has clearly justified the dominant fresh water inflow regulatory force over the tidal forces and the positive influence of the Tsunami on opening the inlet during monsoon failure.

Mangrove forests are one of the most productive and biodiverse wetlands on earth. Yet, these unique coastal tropical forests are among the most threatened habitats in the world. Muthupet mangroves situated in the southeastern coast of India, has a reverse “L” shaped structure. Four cores were collected in 2008, sliced and subsampled at 2.5 cm length. The heavy metals (Mn, Cu, Zn, Ni, Pb, Cr, Cd) and other associated geochemical parameters were evaluated to determine pollution history of Muthupet. An evaluation of the status of heavy metal pollution through the index analysis approach was attempted by computing geoaccumulation index, anthropogenic factor, enrichment factor, contamination factor and degree of contamination, pollution load index and metal pollution index. To compensate for the natural variability of heavy metals in the core sediments, normalization using Al was carried out so that, any anthropogenic metal contributions may be detected and quantified. Results of the study reveal that significant metal contamination exists, and all the metals are found to be higher than continental crustal values. The fine sediments of Muthupet vary between uncontaminated and moderately contaminated with almost no enrichment (EF 10). On comparison, the core collected close to aquafarms and dense mangrove forest (C3) is the most polluted core and the core retrieved where minor rivers drain (C2) is the least polluted.

Kalpakkam, a tiny fishing hamlet dotting the east coast, halfway between Chennai and Pondicherry has become prominent due to the Madras Atomic Power Station. The present study aims at assessing the spatial and temporal distribution pattern of heavy metals (Cd, Pb, Zn, Cu, Ni, Cr, and Fe) from 12 stations along the inner shelf of Bay of Bengal, India, during pre-monsoon (PRM), monsoon, and post-monsoon (POM) seasons. The order of occurrence of the metals in sediments of Kalpakkam is Cr > Zn > Ni > Cu > Pb > Cd (excluding Fe since unit is in %) and exhibits a unique seasonal pattern with the highest values (average) during POM except for Cd which shows highest (average) concentration during PRM. In order to determine the sample association according to their geochemical composition and their granulometric characteristics, a correlation matrix was generated and sediment pollution indices viz., sediment enrichment factor and geoaccumulation index were computed. The results confirm anthropogenic input of Cd to nearshore sediments of Kalpakkam. Sources of Cd can be attributed to dredging activities at Edaiyur, direct dumping and sewage sludge from anthropogenic activities, which reach the study area through the Buckingham Canal opening at the backwaters—Sadras and Edaiyur, and extreme use of antifouling paints by fishing trawlers.

Data from satellites are invaluable for applications including long-term climate studies and engineering design. Most present applications of wind-wave research for coastal engineering and environmental purposes involve the use of numerical models that simulate the evolution of directional wave energy spectra in time or space or both which can be used to forecast climate change, currents, and waves. Using NCEP winds, the wave climate over the offshore region was simulated from January 2004 to December 2005 using MIKE 21 offshore spectral wave module (OSW). Three cyclones Baaz, Fanoos and 7B occurred in 27 November–3 December (2005), 5–12 December (2005) and 15–24 December (2005), respectively, happen to fall during the period of study. Hence, the applicability of this model in the prediction of wave conditions during cyclones was carried out. The significant wave heights in the North Indian Ocean are in the range of 1.0–1.5 m increasing to a maximum of 3.3 m during cyclonic conditions. The results have proved the suitability of OSW Model in the prediction of the offshore wave climate during extreme conditions.

Muttukadu Backwater, located on the east coast of Tamilnadu, is one of healthiest estuarine environments in the region. A study pertaining to seasonal variations in physico-chemical properties in water was conducted at nine sites of Muttukadu Backwater for a period of one year (January to December 2009). Multivariate statistical techniques, such as cluster analysis and principal component analysis (PCA), were applied to evaluate the variation in water quality of Muttukadu Backwater and to identify pollution sources. In order to analyze water quality, a geographic information systems (GIS) software package, Arc GIS version 9.3, was used (Esri, Redlands, California). An interpolation technique, inverse distance weighting, was used to produce the spatial distribution of water quality parameters over the backwater. The purpose of the technique was to aid in protection of the environment and ecology of the estuary and aid in effective management. In the present study, observed values of salinity, nitrite, nitrate, ammonia, total nitrogen, phosphate, and silicate were significantly high in the estuarine zone. PCA resulted in three factors explaining 75.9% of the total variance. Principal component 1 exhibited a high correlation with significant physico-chemical variables representing the influence of tidal action and sandbar formation. Principal component 2 represented natural pollution as a result of surface runoff. Principal component 3 represented natural pollution as a result of nutrient pollution.

Sediments from Kalpakkam, southeast coast of India were geochemically analyzed to document the provenance, tectonic setting, and role of chemical weathering. The sediments are dominated by quartz (Si), and the higher concentration of Si suggests the presence of quartz (±feldspar) dominated terrigenous sands. The study demonstrates that the sediments are derived from the granitic to gneissic or from a sedimentary source. Beach sediments are deposited in a passive continental margin setting and seabed sediments are deposited in active continental margin. In the A–CN–K diagram, most of the samples fall in the lower part, i.e., below the plagioclase feldspar joint which indicates a low degree of alteration. Only S6 falls just above the plagioclase feldspar joint, close to the AK boundary suggesting a slightly advanced weathering of sediment and source. Beach and seabed sediments lie close to CNK and FM region suggesting the presence of ferromagnesian minerals (likely to be pyroxene) except S6 which falls in the inner triangle of the minerals feldspar, garnet, and biotite in A-CNK-FM diagram. Both CIA and CIW values depict the unweathered nature of the sediments under humid to semi-humid climatic conditions.

The coastal zone is one of the nation's greatest environmental and economic assets. The present research aims at studying the shoreline changes along Vedaranyam coast using conventional and modern techniques including field sampling, remote sensing, and geographical information system (GIS). The study area was divided into three zones. Dynamic Land/Sea polygon analysis was performed to obtain the shore line changes at different time periods between 1930 and 2005. From the multidate shoreline maps, the rate of shoreline change was computed using linear regression rate and end point rate. Further, the shoreline was classified into eroding, accreting, and stable regions through GIS analysis. The eroding, accreting, and stable coastal stretch along Vedaranyam is observed as 18 %, 80.5 %, and 1.5 %, respectively. Net shoreline movement is seaward, i.e., the coast is progressive with an average rate of 5 m/year. A maximum shoreline displacement of 1.3 km towards the sea is observed near Point Calimere. During the Asian Tsunami 2004, the eastern part of the study area showed high erosion. Sediment transport paths derived from the grain size analysis of beach sediments collected during different seasons help to identify the major sediment source and sinks. Point Calimere acts as the major sink for sediments whereas Agastiyampalli and Kodiakkarai are found to be the major sources for the sediment supply along the Vedaranyam coast. Shoreline change study from field and satellite data using GIS analysis confirms that Vedaranyam coast is accreting in nature.

Trihalomethanes, produced as a result of chlorination of drinking water, are considered a potential health hazard. The trihalomethane formation potential (THMFP) of a raw water source may indicate the maximum trihalomethanes (THMs) that are likely to be produced when chlorine reacts with natural organic matter (NOM) present in the water. A study was conducted to evaluate the THMFP in even different drinking water sources in the vicinity of Kalpakkam, a rural township, on the east coast of India. Water from seven stations were analysed for THMFP. THMFP was compared with surrogate parameters such as dissolved organic carbon (DOC), ultraviolet absorbance ( UV254 ) and bromide. The data showed that THMFP was high in water from open wells as compared to closed bore wells, possibly due to more photosynthetic activity. Proximity to sea, and consequently the levels of bromide, was an important factor that influenced THM formation. THM surrogate parameters showed good correlation with THMFP.

To understand the influence of human disturbance on the sediment processes along Kalpakkam coast, India, beach and seabed sediments at 200 m, 500 m, and 1 km into the sea were collected monthly for one year and analyzed. Coarser material close to the tidal inlets (river) and manmade structures (sea wall) indicate the effect of these features in altering the grain size distribution from the general trend. The bivariant plots confirm the dominance of deposition under beach environment. The CM diagram (C — one percentile grain diameter, M — median) divulges that the deposition takes place by suspension and rolling of sediments with C < 1 mm. Linear discriminate function analysis for sediments at Kalpakkam indicates a shallow marine environment for all the samples collected. On the multigroup multivariant discriminant functions V1-V2 diagram, the bulk of the samples from Kalpakkam to Mahabalipuram fall in the field of beach deposition. These results show that reworked sediments, submerged during the Holocene marine transgression are being deposited on present-day beaches by waves, currents and rivers in the study area. Though a high wave energy environment is prevailing in the study area, dominant northward sediment transport along the Kalpakkam-Mahabalipuram coast is not altered due to human interventions. Beach building activity in front of the sea wall ensures the safety of Indira Gandhi Centre for Atomic Research (IGCAR) from wave actions without causing any significant changes to the coastal environment.

Five sediment cores were collected in July 2008 from Buckingham Canal, Ennore, India, a water body that is influenced by domestic and industrial effluents. Downcore variations in trace metal concentrations—Ni, Pb, Mn and Zn at every 2.5 cm increment was determined through acid extraction (hydro fluoric acid, nitric acid and sulphuric acid) and analysed by atomic emission spectrophotometer. The sandy clay environment is composed mostly of medium sized grains. Among the four trace metals studied in five cores, Mn and Ni are the highest and the least occurring metals respectively. Quantitative indices such as geoaccumalation index, anthropogenic factor, enrichment factor, contamination factor and degree and pollution load indices were computed. All these analyses classify Ennore as uncontaminated or moderately contaminated. Zn has the highest anthropogenic factor (2.29) indicating the increasing concentration of Zn in the recent times. Zn enrichment is observed only at surface sediments (top 7.5 cm) C4.

During the last two decades, the coastal environment of southeast India has experienced intense developments in industry, urbanization and aquaculture. Moreover, the 2004 mega tsunami has devastated this coast, thus affecting the coastal sediment characteristics. These two phenomena prompted a study to characterize the sediment, to understand the mechanisms influencing the distribution of heavy metals and to create baseline data for future impact assessment. Results showed that the coastal sediment was carpeted with a mosaic of sand and silty sand with a minor amount of clay. Heavy metal values showed maximum variation for Fe and minimum for Cd. Their average values showed the following decreasing trend: Fe > Cu > Zn > Pb > Cr > Ni > Cd. This study shows that the major source of metals at Kalpakkam coast are land-based anthropogenic ones, such as, discharge from industrial waste, agricultural waste, urban, municipal and slum sewage into the Buckingham canal, which in turn discharges into the sea through backwaters, particularly during northeast monsoon period. A clear signature of the role of backwater discharge increasing the concentration of a few metals in the coastal sediments during monsoon period was observed. Assessments of the degree of pollution, concentration factor (CF), geoaccumulation index (Igeo) and pollution load index (PLI) have been calculated. CF values and Igeo indicated that the coastal sediment is moderately polluted by Cu and Cd. Increase in Cu, Pb and Zn concentration during the monsoon period (October–January) compared to the rest of the year was noticed. Factor analysis and correlation among the heavy metals concluded that Cr, Ni, Cd and Fe are of crustal origin, whereas, Cu, Pb and Zn are from anthropogenic sources. Organic carbon content in the sediment increased during monsoon period, pointing to the role of land runoff and backwater discharge in enhancing its content. The study also elucidates the impact of the recent tsunami in depleting metal content in the coastal sediment as compared to the pre-tsunami period.

Seasonal observations on water-quality parameters and chlorophyll-a in the coastal waters off Kalpakkam, southeast coast of India, was carried out covering an area of about 30 km(2) to find out the variations in physicochemical properties during a monsoonal cycle of the year. Most of the parameters exhibited a significant spatial and seasonal variation. It revealed that the coastal water was significantly influenced by freshwater input from the nearby backwaters during North-east monsoon and post-monsoon periods. A marginal increase in pH from coast towards offshore was noticed during the observation. Relatively low salinity values were observed during pre and post monsoon when compared to summer. Bottom water was found to be highly turbid during summer and pre-monsoon conditions when compared to surface. This could be attributed to the strong northerly wind and northward current prior to the onset of southwest monsoon. N, P and Si based nutrients are relatively high in their concentration in the bottom water. Nitrate was significantly high during post-monsoon and contributed greatly towards total nitrogen as evident from the statistical correlation. Ammonia concentration was relatively high in the bottom samples during all the seasons except on a few occasions during post-monsoon. In general, phosphate and total phosphorous values remained low and particularly so in the surface water. Higher silicate concentration was observed in the bottom water, and there was a reducing trend towards offshore. High chlorophyll-a values were observed during summer and surface water was found to have higher pigment concentrations as compared to the bottom. Results show that phosphate acts as the limiting factor for phytoplankton production particularly during post-monsoon period whereas; none of the nutrients were found to be limiting the phytoplankton growth during other seasons.

Climate change associated with sea level rise (SLR) is one of the major environmental concerns of today. This paper presents an assessment of the impacts of sea level rise on the coastal zone of Kanyakumari District in Tamilnadu, India. Digital Elevation Model (DEM) combined with overlay techniques in GIS are used in determining the inundation zones along the coastal region. The analysis evaluated the impact on coastal fishing villages, landuse, tourist spots and sensitive areas under threat. The vulnerability of the coastal areas in Kanyakumari to inundation was quantified, based on the projected sea level rise scenarios of 0.5 and 1 m. Our findings reveal that approximately 13 km2 of the land area of Kanyakumari would be permanently inundated due to SLR. This would result in loss of land, alteration of the coastal zone and affects coastal ecosystem. From the study, the mitigation measures (engineering measures) and Coastal Zone Management practices that can be taken to protect human life and property from sea level rise are suggested.

An unusual near-surface warming was seen in observations from a moored buoy BD11 at 14°N/83°E, and a nearby Argo profiling float in the Bay of Bengal, during the passage of tropical cyclone Thane, during 25–31 December 2011. The cyclone induced a warming of sea surface temperature (SST) by 0.6°C to the right of the track. Heat budget analysis based on moored observations and satellite data rules out the role of horizontal advection and net heat flux in warming the surface layer. We find that vertical mixing/entrainment in response to the cyclone, in conjunction with a pre-storm temperature inversion (subsurface ocean warmer than SST) led to the observed warming. Pre-storm and post-storm salinity and temperature profiles from an Argo float close to the mooring BD11 have higher vertical resolution than the moored data; they suggest vertical mixing of the upper 70 m of the water column. The moored observations show that the thermal inversion, erased by storm-induced mixing, reappears in a few days.

The Serthalaikkadu creek in Muthupet mangroves region is the only E–W trending coastal strip in the SE coast of India and it also acts as a barrier to natural disasters. Natural, anthropogenic signals and accumulation of elements were studied by collecting sediments from two cores. Textural parameters were studied in detail and carbonates (CaCO3), organic carbon (OC), major (Si, Al, Fe, Na, K, Ca, Mg, P) and trace elements (Mn, Cr, Cu, Ni, Co, Pb, Zn) were determined. Textural parameters, CaCO3, OC and Al-normalized pattern of elements indicate depositional events in core samples that can be directly related to natural events during the last decade. The calculated enrichment, anthropogenic factors and comparison of data indicate that the observed trace metals (especially Pb, Co) are enriched mainly due to the anthropogenic activities in the land as well as in the coastal zone (Palk Strait).

Industrialization coupled with urbanizaton has led to stress in the Buckingham Canal which runs parallel to Bay of Bengal at a distance of around 1 km from the coastline. 4 sediment cores were collected along Ennore - Pulicat stretch to determine acid leachable trace metal concentration. Core samples were collected using gravity corer. The cores were sliced horizontally at 2.5 cm to determine the grain size, sediment composition, pH, organic matter, calcium carbonate, acid leachable trace metals; cadmium, chromium, copper, lead, zinc. The trace metals were extracted using acid mixture containing hydro fluoric acid, nitric acid and sulphuric acid and analysed by atomic emission spectrophotometer. In an attempt to infer anthropogenic input from geogenic input, several approaches including comparison with sediment quality guidelines - ecotoxicological sense of heavy metal contamination and classification by quantitative indexes such as geoaccumalation index, anthropogenic factor, enrichment factor, contamination factor and degree and pollution load index was attempted. Grain size analysis and sediment composition of core samples shows Ennore is sandy in nature having a neutral pH. Organic matter enrichment is observed to a higher extent in core 3. Core 2 at a depth of 5 cm shows organic matter of 9.4 %. calcium carbonate is totally absent at the surface sediments in core 2. Cores collected within the canal showed a higher heavy metal concentration than the cores collected from Pulicat lagoon and 2 km into the Ennore Sea. The trace metal concentration for cadmium, lead and zinc in Ennore does not pose a threat to the sediment dwelling fauna whereas chromium and copper are likely to pose a threat. Quantitative indexes place Ennore under moderately polluted. Ennore is likely to face a serious threat of metal pollution with the present deposition rates unless stringent pollution control norms are adopted.