Integrated hydrochemical and geophysical studies for assessment of groundwater pollution in basaltic settings in Central India

The Pithampur Industrial sectors I, II, and III, located approximately, 45 km from Indore in Central India have emerged as one of the largest industrial clusters in the region. Various types of industries ranging from automobiles to chemicals and pharmaceuticals have been set up in the region since 1990. Most of the industries have effluent treatment plants (ETP) for treating wastewater before its disposal on land and/or in water body. The present study is an attempt to assess the groundwater quality in the watersheds surrounding these industrial sectors to develop the baseline groundwater quality in order to enable the policy makers to facilitate decisions on the development of industries in this region. The industries are located in two sub-watersheds, namely, Gambhir river sub-watershed and Chambal river sub-watershed. Geologically, the study area is located in the Deccan traps of Cretaceous to Paleocene age. The different basaltic flow units underlie clayey soils varying in thickness from 2–3 m. The aquifer is mostly of unconfined nature. Samples have been collected from a network of observation wells set up in the watersheds. The water quality analysis of the groundwater samples has been carried out six times during three hydrological cycles of 2004, 2005, and 2006. The results indicate that a few observation wells in the vicinity of the industrial clusters have very high TDS concentration and exceed the Bureau of Indian Standards (BIS) guideline for TDS concentration. The contamination of groundwater has been more severe in the Gambhir watershed as compared to the Chambal watershed. The presence of the impermeable clay layers has resulted in a slow migration of contaminants from the sources. The findings reveal that there is no significant groundwater contamination in the Pithampur industrial sectors except in the vicinity of the industrial clusters, which indicates that there is good environmental space available for the expansion of industrial units in the Pithampur industrial hub.     

A Multivariate Time Series Approach to Study the Interdependence among O3, NO x , and VOCs in Ambient Urban Atmosphere

A multivariate time series approach vector autoregression (VAR) along with impulse response function and variance decomposition technique has been employed to look into the interrelationship among O₃, NO, NO₂, and volatile organic compounds (VOCs, namely, benzene, ethylbenzene, toluene, and xylene in the present study) using 3 months long continuous time series data of 1 h average concentration of these pollutants at one of the traffic sites in Delhi, India. It is found that the VAR of order 2 (i.e., past two lagged values of 1 h interval) is sufficient to represent the observed time series at the station studied. The impulse response function and variance decomposition analysis indicate that O₃ concentration shows an immediate rise and persists for a longer duration (typically 8–10 h) once the impulse of NO₂, benzene, ethylbenzene, or xylene is given in the ambient environment. However, in case of toluene, the reverse effect has been observed. Since O₃ forms in the troposphere due to photolysis of NO₂, it is not surprising that its impulse triggers O₃ formation in the ambient environment. However, in case of VOCs, this has been attributed to their tendency to show higher inclination toward intermediary reactions leading to the formation of O₃ rather than their (VOCs) reaction with O₃. Among VOCs, only toluene has been observed to show higher inclination toward its reaction with O₃. Apart from this, variance decomposition technique also reveals that the relation of NO with NO₂ is more important than the relation of NO with O₃ creating a conducive atmosphere for O₃ formation in the present scenario. Thus, the multivariate time series approach provides significant insight about the role played by the dominant individual VOCs and NO _x in influencing the O₃ concentration in ambient urban atmosphere whereas a photochemical modeling approach gives an overall view of NO _x and VOCs behavior with respect to O₃ by using the O₃ isopleth technique.     

Assessment of ground water quality for drinking purpose, District Nainital, Uttarakhand, India

The ground water quality of District Nainital (Uttarakhand, India) has been assessed to see the suitability of ground water for drinking and irrigation applications. This is a two-part series paper and this paper examines the suitability of ground water including spring water for drinking purposes. Forty ground water samples (including 28 spring samples) were collected during pre- and post-monsoon seasons and analyzed for various water quality constituents. The hydrochemical and bacteriological data was analyzed with reference to BIS and WHO standards and their hydrochemical facies were determined. The concentration of total dissolved solids exceeds the desirable limit of 500 mg/L in about 10% of the samples, alkalinity values exceed the desirable limit of 200 mg/L in about 30% of the samples, and total hardness values exceed the desirable limit of 300 mg/L in 15% of the samples. However, no sample crosses the maximum permissible limit for TDS, alkalinity, hardness, calcium, magnesium, chloride, sulfate, nitrate, and fluoride. The concentration of chloride, sulfate, nitrate, and fluoride are well within the desirable limit at all the locations. The bacteriological analysis of the samples does not show any sign of bacterial contamination in hand pump and tube-well water samples. However, in the case of spring water samples, six samples exceed the permissible limit of ten coliforms per 100 ml of sample. It is recommended that water drawn from such sources should be properly disinfected before being used for drinking and other domestic applications. Among the metal ions, the concentration of iron and lead exceeds the permissible limit at one location whereas the concentration of nickel exceeds the permissible limit in 60 and 32.5% of the samples during pre- and post-monsoon seasons, respectively. The grouping of samples according to their hydrochemical facies indicates that majority of the samples fall in Ca–Mg–HCO₃ hydrochemical facies.     

Assessment of daily intake of trace elements by Kakrapar adult population through ingestion pathway

Concentration of trace elements such as Fe, Cu, Ni, and Zn were measured in cereals, pulses, vegetables, fish, meat, milk, egg, and water samples collected around Kakrapar, Gujarat, India. A wide variation of the trace element concentration was observed among all the dietary matrices. The concentration of Fe is comparatively more in all the dietary matrices. The concentrations of these elements are translated into intake rates through ingestion pathways. Daily intake (milligrams/day) of Fe, Cu, Ni, and Zn by adult population of Kakrapar, Gujarat were 16.5 ± 6.2, 3.3 ± 1.2, 1.8 ± 1.0, and 3.6 ± 1.3, respectively. Dietary sources of Fe, Cu, and Ni by Kakrapar adult population are comparable with RDA. In case of Zn, the daily dietary intake is comparatively lower than that of RDA.     

The effects of meteorological parameters in ambient noise modelling studies in Delhi

The acoustic environment in urban areas has gained prominence in recent times due to rapid industrial and commercial development in metropolitan cities. Various attempts have been made to predict and model the trends in urban ambient noise levels using different statistical and dynamic models. The present study makes an attempt to examine the role of meteorological parameters affecting the ambient noise levels in Delhi. The results show significant improvement in overall noise scenario of Delhi since the introduction of compressed natural gas vehicles in public transport of Delhi. The noise level is significantly reduced by high vegetation cover as well as by low relative humidity over Delhi. The regression models developed for the present study clearly show the significant contribution of meteorological parameters in governing the ambient noise levels in Delhi.     

Modelling of lindane transport in groundwater of metropolitan city Vadodara,Gujarat, India

Migration pattern of organochloro pesticide lindane has been studied in groundwater of metropolitan city Vadodara. Groundwater flow was simulated using the groundwater flow model constructed up to a depth of 60 m considering a three-layer structure with grid size of 40?×?40?×?40 m³. The general groundwater flow direction is from northeast to south and southwest. The river Vishwamitri and river Jambua form natural hydrologic boundary. The constant head in the north and south end of the study area is taken as another boundary condition in the model. The hydraulic head distribution in the multilayer aquifer has been computed from the visual MODFLOW groundwater flow model. TDS has been computed though MT3D mass transport model starting with a background concentration of 500 mg/l and using a porosity value of 0.3. Simulated TDS values from the model matches well with the observed data. Model MT3D was run for lindane pesticide with a background concentration of 0.5?μg/l. The predictions of the mass transport model for next 50 years indicate that advancement of containment of plume size in the aquifer system both spatially and depth wise as a result of increasing level of pesticide in river Vishwamitri. The restoration of the aquifer system may take a very long time as seen from slow improvement in the groundwater quality from the predicted scenarios, thereby, indicating alarming situation of groundwater quality deterioration in different layers. It is recommended that all the industries operating in the region should install efficient effluent treatment plants to abate the pollution problem.     

Nitrate pollution of wells: pollution prevention policy options

Irrigated agriculture is a major sector of agricultural economy where high value crops are grown with substantial input of fertilizers and pesticides. High concentrations of nitrate and pesticides have been observed in ground water beneath irrigated areas in humid regions, where irrigation is practiced on sandy soils that have low water-holding capacity. Data from these areas indicate that irrigation wells are typically screened in the bottom part of the aquifer (which contain coarser deposits) whereas the domestic wells are screened just below the water table. Monitoring results from several irrigated areas have shown the stratification of dissolved inorganic and organic chemicals in the aquifer. Nitrate in such systems is typically highest near the surface. This has serious health implications for the rural population that relies upon shallow ground water for drinking. Current environmental policy towards pollution reduction focuses on improved management practices to reduce the loading of the chemicals to ground water. However, an engineering issue, dealing with the design of the irrigation and domestic wells has not been addressed. A design modification for the irrigation and domestic wells can reduce the risk of high nitrate ground water being pumped by domestic wells. A proposal to convert a deep vertical irrigation well to a series of small-capacity shallow vertical wells or a large-capacity horizontal well and slight deepening of the domestic wells was examined through simulations. This can reduce the nitrate concentration of ground water in domestic wells dramatically and use the high nitrate water for crop irrigation.     

Nitrate pollution of wells: pollution prevention policy options

Irrigated agriculture is a major sector of agricultural economy where high value crops are grown with substantial input of fertilizers and pesticides. High concentrations of nitrate and pesticides have been observed in ground water beneath irrigated areas in humid regions, where irrigation is practiced on sandy soils that have low water-holding capacity. Data from these areas indicate that irrigation wells are typically screened in the bottom part of the aquifer (which contain coarser deposits) whereas the domestic wells are screened just below the water table. Monitoring results from several irrigated areas have shown the stratification of dissolved inorganic and organic chemicals in the aquifer. Nitrate in such systems is typically highest near the surface. This has serious health implications for the rural population that relies upon shallow ground water for drinking. Current environmental policy towards pollution reduction focuses on improved management practices to reduce the loading of the chemicals to ground water. However, an engineering issue, dealing with the design of the irrigation and domestic wells has not been addressed. A design modification for the irrigation and domestic wells can reduce the risk of high nitrate ground water being pumped by domestic wells. A proposal to convert a deep vertical irrigation well to a series of small-capacity shallow vertical wells or a large-capacity horizontal well and slight deepening of the domestic wells was examined through simulations. This can reduce the nitrate concentration of ground water in domestic wells dramatically and use the high nitrate water for crop irrigation.     

An investigation into the acid content of aerosols in the ambient air at the Taj Mahal, Agra

A chemical analysis of suspended particulate matter (SPM) collected near the world famous Taj Mahal monument at Agra has been carried out. SPM samples collected on glass fibre filters were analysed for water-soluble sulphate, nitrate, chloride and ammonium ions. The data were derived from over 200 samples (each of 24 h), collected continuously during the winter periods (October through to March) of 1984-1985 and 1985-1986. The SO(4)(2-) and NO(3)(-) components are acidic in nature causing corrosion and effects on visibility, and so were studied in more detail. Mean values for SO(4)(2-) and NO(3)(-) derived from two-year data are 7.2 microg m(-3) and 8.2 microg m(-3), respectively. The SO(4)(2-)/SO(2) and NO(3)(-)/NO(2) ratiosobserved indicate faster conversion of SO(2) to SO(4)(2-) than NO(2) to NO(3)(-), the maximum levels being in January. Thus, both SO(4)(2-) and NO(3)(-) results appear to offer more promising indices of air quality than do SPM data alone.