High fluoride in groundwater and associated non-carcinogenic risks at Tiruvannamalai region in Tamil Nadu, India.

The present investigation in the Tiruvannamalai region is about high fluoride contamination of groundwater samples from bore wells and open wells. About 75% of groundwater samples were found predominantly containing the fluoride content greater than the acceptable limit of 1.5 mg/L in the ranges 1.51 - 2.00 mg/L (23%), 2.01 - 3.00 mg/L (36%) and greater than or equal to 3.01 mg/L (16%) as per WHO. The other water quality parameters were found within the permissible limit of WHO. Taking the groundwater sources into consideration, the non - carcinogenic risk due to high fluoride concentration in groundwater sources revealed that teen - aged (98%), Children (92%) and Infant (98%) categories were at greater risk than those under Men (50%) and Women (69%) categories. The mapping was done on the spatial distribution of fluoride concentration in groundwater and the associated health risk by Ordinary Kriging. The correlation coefficients among the parameters witnessed that the hydro-chemical facies are interdependent. Box - Whisker plots illustrated the dispersion of various water quality parameters. The WQI data represented the quality of groundwater in view of potable nature due to dissolved ions. The Gibbs, bivariate mixing and the scatter plots ascribed the dissolution of carbonate and silicate minerals which dominate the groundwater chemistry. The factor analysis detailed the extracted loadings of different parameters of groundwater sources and differentiated the percentage variance values between bore well and open well sources.

Micro-plastic pollution along the Bay of Bengal coastal stretch of Tamil Nadu, South India.

In the present-day context, micro-plastic particles in a marine environment are increasingly ubiquitous and of considerable persistence. In line with the micro-plastic pollution, the present contribution is devoted to the investigation of micro-plastic particles (MPs) along the urban sandy beach called Marina, the renowned longest beach in India. Along the sea coast of about 5 km, the quantification of micro-plastic particles using optical microscope evidenced the granular, filamentous, filmy and tubular fragments in a total of 72 marine samples including those filtered in the marine water column (WAT; 24 samples), those found in wet sediment (WET; 24 samples) and those found in dry sand (DSS; 24 samples). The filamentous-typed plastics of 79%, 57% and 52%, respectively in WET, WAT and DSS dominated over the other granular and tubular types. The micro-plastic particles were in the range of 60-820 items per m3, 60-1620 items per kg and 20-1540 items per kg for WAT, WET and DSS, respectively. The standard deviation for the microplastics abundance were 193.1, 396.6 and 364.6 for WAT, WET and DSS respectively. Upon visual inspection, the micro particles were observed in eight different colors and most of the samples were found to contain two different fragment types. Apart from the optical microscopic examination, the micro-plastics particles were studied by scanning electron microscope (SEM) coupled with elemental analysis by energy dispersive spectroscopy (EDS). The energy spectral graphs displayed that the micro-filaments and micro-tubular particles contained polyesters and fluoro-polymers. The presence of few micro-filaments of polypropylene and polyethylene was also evidenced from their atomic percentage values of carbon of about 88% and 93%, respectively. The presence of fluoro-polymers and polyesters was also confirmed by Fourier Transform Infra-Red (FTIR). Excepting the fluoro-polymers, the micro-plastics particles contained elements arising from sea water (Na, Cl, S, Mg, Ca, K). Heavy metals such as Cu, Mn, Mo, Ru and Rh were observed in micro-tubular fragments. Fe and Ti elements were detected with the highest atomic percentage of 17.19 and 19.84 in micro-tubular fragments. All the observations and analyses give a photography of the nature and the spatial distribution of MPs along this Indian beach.