Publications by authors named "Hema Achyuthan"

El Niño Southern Oscillation (ENSO) is one of the dominant climate modes influencing global precipitation and temperature. ENSO has a large impact on the monsoonal precipitations over the Indian subcontinent and thereby influences hydrological conditions. Due to dearth of long-term instrumental records of the hydrological parameters on sufficient spatial resolution, it is difficult to assess the impact of ENSO on regional hydrology.

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The present study was carried out to determine the characteristics, distribution, and abundance of plastic debris in 25 sediment samples collected from the Poompuhar beach, southeast coast of India. The result reveals that the mean plastic debris abundance was 42 ± 27 particles/m dry weight (dw) (1 SD, n = 25) with higher concentrations in the river mouth. The dominant shapes in the study area were fragment (70.

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South Asia hosts the world's youngest Acheulean sites, with dated records typically restricted to sub-humid landscapes. The Thar Desert marks a major adaptive boundary between monsoonal Asia to the east and the Saharo-Arabian desert belt to the west, making it a key threshold to examine patterns of hominin ecological adaptation and its impacts on patterns of behaviour, demography and dispersal. Here, we investigate Palaeolithic occupations at the western margin of the South Asian monsoon at Singi Talav, undertaking new chronometric, sedimentological and palaeoecological studies of Acheulean and Middle Palaeolithic occupation horizons.

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Inevitable use of plastic materials in our day-to-day life has led to the entry of microplastic into aquatic environments, which are plastics less that than 5 mm. Microplastic is of great concern in recent years due to its impact on humans and aquatic organisms since they absorb organic contaminants and pathogens from the surrounding media due to higher surface and volume ratio. This is the first study attempted to study the distribution and source of microplastic contamination in Red Hills Lake which is one of the freshwater systems supplying water to the North of Chennai city.

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Concentrations of eight bisphenol analogues (BPs) including BPA, BPS, and BPF were determined in surface waters collected from select rivers in Japan, Korea, China, and India. BPA was found at a concentration in the range of several tens to several hundreds of nanograms per liter in most of the rivers surveyed and some of the highest concentrations (54-1950 ng/L) were found in rivers in Chennai, India. Concentrations of BPF were one to two orders of magnitude higher than those of BPA in river and sea waters collected from Japan, Korea and China, which suggested that BPF is a major contaminant in surface waters in several Southeast Asian countries.

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Heavy metals disposed through anthropogenic activities find their way into the oceans and seas through the rivers or through direct fall out from factory effluents. These heavy metals resuspend back into the water column along with the sediments and are known to affect the marine animals. Marine animals like fish, prawn, crab and mussel were collected along the East Coast (off Pulicat lake to Chennai Harbour) to evaluate trace metal concentrations in various tissues.

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