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Ninety-nine benthic foraminiferal species belonging to 41 genera, 26 families, 17 superfamilies and 5 suborders have been identified from 84 samples which were collected from beach (23 nos), offshore (24 nos), estuaries (8 nos), inland (23 nos) and one pit sample (6 nos), between Cuddalore and Nagapattinam in the tsunami affected coastal environment. Out of 99 species, only 20 species are living ones. The following species are appreciably distributed in different stations, namely Ammonia beccarii, Elphidiumcrispum, Rosalina globularis, Asterorotaliatrispinosa and Pararotalianipponica. The total distribution of foraminifera is higher at Cuddalore and Nagapattinam whereas at Pudupettai and Samadanpettai it is noticed in the lower order. Organic matter and living species show positive relation. No relationship is observed between dead species and the organic matter, which suggests that the dead species recorded in the sediment, must have been primarily drifted/transported as empty calcareous shells. From the sand/silt/clay ratios, it is inferred that the sediments are normally sandy in nature but silty sand dominates at deeper depths. Carbonate content establishes a positive correlation with all parameters. A fluctuation of salinity values in offshore regions indicates the influx of fresh water from Colleroon river. From the overall studies of foraminiferal distribution in this region, it may be inferred that the species distribution in the offshore region is mainly derived from the inner shelf region. To observe the earlier changes in climactic condition in marine environment mainly based on information from marine sediments. The collected samples from our study area marine sediments contain a variety of foraminifera, which archive climactic information from both planktonic and benthic assemblages and in their sedimentological compositions. [ABSTRACT FROM AUTHOR]

We use electrical resistivity data arrayed in a 2715 km region with 30 locations to identify the saline water intrusion zone in part of Cauvery deltaic region, offshore Eastern India. From this dataset we are able to derive information on groundwater quality, thickness of aquifer zone, structural and stratigraphic conditions relevant to groundwater conditions, and permeability of aquifer systems. A total of 30 vertical electrode soundings (VES) were carried out by Schlumberger electrode arrangement to indicate complete lithology of this region using curve matching techniques. The electrical soundings exhibited that H and HK type curves were suitable for 16 shallow locations, and QH, KQ, K, KH, QQ, and HA curves were fit for other location. Low resistivity values suggested that saline water intrusion occurred in this region. According to final GIS map, most of the region was severely affected by seawater intrusion due to the use of over-exploitation of groundwater.The deteriorated groundwater resources in this coastal region should raise environmental and health concerns. [ABSTRACT FROM AUTHOR]

Marina beach in Chennai metropolitan city attracts numerous tourists from all around the world, and it is an important ecological habitat for many life forms. Rapid urbanisation and industrial developments have led to excessive use of plastics and increased the amount of plastic waste generated in the natural environment. This first baseline study evaluates the microplastic (MP) accumulation in beach surface sediments of Marina and Pattinapakkam beaches through FTIR, AFM and SEM analyses. Sediment samples were collected from 40 stations and different types of MP polymers were identified. On average, 459 (60.8%) and 297 (39.2%) MP particles were found in the samples from Marina and Pattinapakkam beaches, respectively. We found that polyethylene types and additives are the dominant MPs in both areas. This study provided us with new insights into the human activities and natural processes in these marine environments. To solve the problem of plastic accumulation in the marine environment, the government should first play an active role in addressing the problem of plastic waste by introducing laws to control the sources of plastic waste and the use of plastic additives. [Display omitted] • This research evaluates the properties of MPs in surface beach sediments. • MPs ratio from Marina and Pattinapakkam beaches are 60.8 and 39.2%. • Polyethylene types and additives are the dominant MPs in both areas. • MPs originate from natural and human influences. [ABSTRACT FROM AUTHOR]

Surface sediment samples from the Tirumalairajan river estuary were studied for grain size pattern, organic matter, and heavy metals (Fe, Mn, Zn, and Pb) using the sequential and bulk metal extraction methods to evaluate metal behavior. Ten surface sediment samples were collected during the monsoon and summer seasons of the year 2009. The observed orders of concentrations of heavy metals in the sediments were as follows: Fe > Mn > Zn > Pb. The results obtained from sequential extraction showed that, among the metals studied, a larger portion of the metals were associated with the residual phase, although they are available in other fractions. The low concentration of metals available in bioavailable phases indicated that the sediments of Tirumalairajan river estuary were relatively unpolluted. Correlation analysis was also carried out to understand the associations of metals in different phases with sand, silt, clay, and organic matter. To understand the risk of heavy metals to sediment-dwelling organisms, the data were compared with risk assessment code and sediment quality values using the screening quick reference table. The main source of metals to the estuary is from the irrigation field and its associated activities in the study area. [ABSTRACT FROM AUTHOR]

Distribution and ecological risk assessment of heavy metals in surface sediments of Vellar, Coleroon and Tirumalairajan estuaries were investigated. Fifteen sediment samples from five locations in each estuary were collected during March 2010, and organic matter, grain size and metal contents (Al, Fe, Mn, Zn, Cu and Pb) were characterized. Mean metal levels in three estuaries were followed in a descending order as Al > Fe > Zn > Mn > Cu > Pb (Vellar and Coleroon) and as Al > Fe > Zn > Cu > Mn > Pb in Tirumalairajan estuary sediments. Concentration pattern revealed that the mean values of Vellar estuary are enriched with Al (20,528 μg/g), Fe (16,368 μg/g), Zn (102.7 μg/g), Mn (63.5 μg/g), Cu (47.6 μg/g) and Pb (7.9 μg/g). Coleroon and Tirumalairajan surface sediments concentration suggested Al (4813 μg/g), Fe (2734 μg/g), Zn (47.6 μg/g), Mn (34.2 μg/g), Cu (23 μg/g) and Pb (9.2 μg/g) and Al (5348 μg/g), Fe (2257 μg/g), Zn (36 μg/g), Cu (23.5 μg/g), Mn (21.9 μg/g) and Pb (3.7 μg/g), respectively. Correlation analysis and two-way joining cluster analysis clearly exhibited the good relationship of grain size and organic matter with metals. Geo-accumulation index (Igeo) revealed that the values of Zn (2) and Cu (1) were slightly higher in Vellar estuary when compared to the other two estuaries. The enrichment factor (EF) and pollution load index values showed that the Vellar estuary was more contaminated by Zn, Pb and Cu than the Coleroon and Tirumalairajan estuaries. This study suggested that heavy metal input to the Vellar estuary should be regulated in the near future, particularly with regard to Zn, Cu and Pb on the basis of threshold effect level and effects range low benchmarks when compared to the other two estuaries. Comparative results with three estuaries suggested anthropogenic input rather than a natural process as a contamination source. This study will help in developing the effective strategies of pollution control and sediment remediation of the estuarine and marine environments. [ABSTRACT FROM AUTHOR]