Health risks associated with fluoride intake from rural drinking water supply and inverse mass balance modeling to decipher hydrogeochemical processes in Vattamalaikarai River basin, South India.

Preliminary investigation reveals that fluorosis is reported due to the continuous intake of fluoride-rich groundwater in Vattamalikarai River basin, Tamil Nadu, India. A detailed study was attempted for evaluating the health risks associated with the intake of fluoride-rich groundwater supplied to the rural community. Groundwater samples were collected from 60 and 58 dug and tube wells during winter and southwest (SW) monsoon seasons respectively. The samples were analyzed for the determination of fluoride and other chemical parameters to examine the fitness for drinking water. Spatio-temporal variation maps reveal that fluoride concentration is high during SW monsoon season when compared with the winter season in this region. The fluoride bearing minerals present in hornblende-biotite gneiss and charnockite rock formations leached into the groundwater during rock-water interaction. To understand the subsurface hydrogeochemical reactions, inverse mass balance model was developed using NETPATH code. The model output indicates that calcite dilution, silicate (hornblende and biotite) weathering, ion exchange (Ca/Na and Mg/Na) and illite precipitation are the dominant processes controlling the groundwater chemistry along the flow paths. Non-carcinogenic risks to children and adults (women and men) were evaluated by working out intake exposure of groundwater. Hazard quotient (HQ) based on fluoride intake was calculated for children and adults. It varied from 0.08 to 2.21 with an average of 1.07 for adults. For children, it varied from 0.01 to 2.99 with the mean of 1.44. About 78%, 69% and 61% of the samples fall under the risk category for children, women and men during winter season. However, more number of samples possessed health risks (83% of samples for children, 73% of samples for women and 64% of samples for men) during SW monsoon season.

Assessment of heavy metals in the surface sediments of the Emerald Lake using of spatial distribution and multivariate techniques.

The study aims to assess the heavy metals such as cobalt (Co), nickel (Ni), lead (Pb), chromium (Cr), cupper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) from 25 surface sediment samples at different sites of the Emerald Lake, Tamilnadu, India using spatial distribution and multivariate techniques like Pearson correlation matrix and principal component analysis. From the result, the ranges of Fe, Cu, Cr, Mn, Zn, Ni, Co, and Pb are noticed to be 78,128 to 132,876; 314 to 462; 336 to 523; 520 to 701; 20.1 to 53.21; 128 to 215; 91 to 129.9; and 151 to 158 µg g-1, respectively. The order of the average heavy metals concentration is Fe > Mn > Cr > Cu > Pb > Zn > Co > Ni. From the result, Ni, Cu, Cr, Pb, and Cd are found to be considerably correlated as they are usually related to anthropogenic activities, wastewater, and sewage. From the principal corresponding analysis (PCA) results retrieved from PC3 suggest that Fe, Mn, Cr, Cu, Pb, and Ni have common origin and are mainly due to anthropogenic input, inorganic fertilizers in agriculture, human activities, sewage effluents, traffic, and boat activities. The study relatively provides a significant approach for heavy metal pollution origin in the surface sediment in the Emerald Lake.

Energy production through organic fraction of municipal solid waste-A multiple regression modeling approach.

In the 21st century, people migrated from rural to urban areas for several reasons. As a result, the populations of Indian cities are increasing day by day. On one hand, the country is developing in the field of science and technology and on the other hand, it is encountering a serious problem called 'Environmental degradation'. Due to increase in population, the generation of solid waste is also increased and is being disposed in open dumps and landfills which lead to air and land pollution. This study is attempted to generate energy out of organic solid waste by the bio- fermentation process. The study was conducted for a period of 7 months at Erode, Tamilnadu and the reading on various parameters like Hydraulic retention time, organic loading rate, sludge loading rate, influent pH, effluent pH, inlet volatile acids, out let volatile fatty acids, inlet VSS/TS ratio, outlet VSS/TS ratio, influent COD, effluent COD and % of COD removal are recorded for every 10 days. The aim of the present study is to develop a model through multiple linear regression analysis with COD as dependent variable and various parameters like HRT, OLR, SLR, influent, effluent, VSS/TS ratio, influent COD, effluent COD, etc as independent variables and to analyze the impact of these parameters on COD. The results of the model developed through step-wise regression method revealed that only four parameters Influent COD, effluent COD, VSS/TS and Influent/pH were main influencers of COD removal. The parameters influent COD and VSS/TS have positive impact on COD removal and the parameters effluent COD and Influent/pH have negative impact. The parameter Influent COD has the highest order of impact, followed by effluent COD, VSS/TS and influent pH. The other parameters HRT, OLR, SLR, INLET VFA and OUTLET VFA were not significantly contributing to the removal of COD. The implementation of the process suggested through this study might bring in dual benefit to the community, viz treatment of solid waste and creation of energy.

Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India.

The present work is employed in Omalur Taluk (study area 538.10 km(2)), Salem District, Tamil Nadu, India. Eighty-nine groundwater samples were collected during pre-monsoon (May) 2011 and were analyzed for major cations and anions. The irrigational parameters like; EC, Kelley's ratio, sodium absorption ratio (SAR) values, Mg(2+) hazards, HCO3 (-) and residual sodium carbonate (RSC) have been worked out to know the suitability of the groundwater for irrigational purpose. Wilcox diagram indicates that out of 89 samples, 39 samples belong to good permissible category and Doneen diagram revealed that 98.88 % of the groundwater samples fall in Class I. The plotting of SAR values in USSL diagram indicates that all the samples have low SAR value. Out of 89 samples, 44 samples were in C3-S1 field. This implies that no alkali hazard is anticipated to the crops. In 44 locations (49.44 %), samples fall within C3-S1 category. This category is suitable for irrigation purpose. However, the concentration of bicarbonate was in significant amount showing 82 % of sites under "increasing problem" and the 4 % sites under "Severe Problem" zones. Finally, the above-said results are taken into a Geographic Information System (GIS) platform. To understand the spatial distribution of unsuitable zones, ArcGIS was employed. The present work reveals that groundwater in the Omalur Taluk is of good quality and is suitable for all uses including interbrain water transfer in the region.

Irregular shedding of Blastocystis hominis.

The shedding pattern of the protozoan parasite, Blastocystis hominis, is investigated in man and in experimental animal infections. The shedding pattern of the vacuolar and cystic forms of Blastocystis hominis in infected individuals have been shown in the present study to be irregular. The study shows that there is marked fluctuation in the shedding of the parasite from day to day, varying from as high as 17 to 0 per x40 microscopic field. The cystic stages when estimated in 8 Blastocystis-infected individuals ranged from as high as 7.4x10(5) cysts per gram of stool to 0. The shedding of cystic and vacuolar forms observed over a period of 20 days in experimentally-infected Wistar rats were not only shown to be irregular but the amount varied from host to host. The study has important diagnostic implications in that the stool samples must be collected more than once from patients showing clinical signs and symptoms to eliminate the cause of it to Blastocystis. The study also shows that there are asymptomatic individuals who pass a large amount of cysts as such individuals should be treated to prevent transmission to others.

Blastocystis in animal handlers.

The present study investigated whether people working closely with animals were at higher risk of getting infected with Blastocystis hominis. The prevalence of the parasite was determined in two population groups, i.e., animal handlers and normal healthy individuals who did not work with animals. In all, 105 stool samples were collected from animal handlers from 2 local research institutions, a local zoo, and a local abattoir and 163 stool samples were collected from normal healthy individuals residing in high-rise flats in the city. The in vitro culture method used in the study detected that 41% of 105 animal handlers and 17% of 163 flat-dwellers in the city were positive for Blastocystis. This statistically significant finding (P = 0.0000313) shows that people who work closely with animals do stand at risk of acquiring Blastocystis infection.