Evaluation of hexachlorocyclohexane contamination from the last lindane production plant operating in India

Purpose

??-Hexachlorocyclohexane (HCH), ??-HCH, and lindane (??-HCH) were listed as persistent organic pollutants by the Stockholm Convention in 2009 and hence must be phased out and their wastes/stockpiles eliminated. At the last operating lindane manufacturing unit, we conducted a preliminary evaluation of HCH contamination levels in soil and water samples collected around the production area and the vicinity of a major dumpsite to inform the design of processes for an appropriate implementation of the Convention.

Methods

Soil and water samples on and around the production site and a major waste dumpsite were measured for HCH levels.

Results

All soil samples taken at the lindane production facility and dumpsite and in their vicinity were contaminated with an isomer pattern characteristic of HCH production waste. At the dumpsite surface samples contained up to 450?g?kg^?1 ?? HCH suggesting that the waste HCH isomers were simply dumped at this location. Ground water in the vicinity and river water was found to be contaminated with 0.2 to 0.4?mg?l^?1 of HCH waste isomers. The total quantity of deposited HCH wastes from the lindane production unit was estimated at between 36,000 and 54,000?t.

Conclusions

The contamination levels in ground and river water suggest significant run-off from the dumped HCH wastes and contamination of drinking water resources. The extent of dumping urgently needs to be assessed regarding the risks to human and ecosystem health. A plan for securing the waste isomers needs to be developed and implemented together with a plan for their final elimination. As part of the assessment, any polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) generated during HCH recycling operations need to be monitored.     

Urbanization and its impact on groundwater: a remote sensing and GIS-based assessment approach

The perils of unplanned urbanization and increasing pressure of human activities on hydro-geomorphologic system often result in modification of the existing recharge mechanism, which leads to many environmental consequences. In the present research, an attempt has been made to investigate the applicability of remote sensing and geographical information system (GIS) in dealing with spatial and temporal variability of dynamic phenomena, like urbanization and its impact on groundwater. This paper covers primarily, quantitative and qualitative impacts of urban growth on the behavior of aquifer in Ajmer city (India). Urban growth of the Ajmer city in last 17 years has been estimated from the satellite images. Database related to urbanization and groundwater has been created in GIS. Groundwater recharge has been computed using a water balance approach known as Water Level Fluctuation Methodology. Recharge estimation methodology has been implemented in GIS to introduce the spatial variability of hydro-geological characteristics. Further, temporal and spatial variations in groundwater quality and quantity have been correlated with urban growth using overlay analysis in GIS. The study reveals a general decline in water table and quality with urbanization. Further, remote sensing and GIS technologies have been found useful in assessment of spatial and temporal phenomena of urbanization and its impact on groundwater system.     

Recycling polymeric waste from electronic and automotive sectors into value added products

The environmentally sustainable disposal and recycling of ever increasing volumes of electronic waste has become a global waste management issue. The addition of up to 25% polymeric waste PCBs (printed circuit boards) as fillers in polypropylene (PP) composites was partially successful: while the tensile modulus, flexural strength and flexural modulus of composites were enhanced, the tensile and impact strengths were found to decrease. As a lowering of impact strength can significantly limit the application of PP based composites, it is necessary to incorporate impact modifying polymers such as rubbery particles in the mix. We report on a novel investigation on the simultaneous utilization of electronic and automotive rubber waste as fillers in PP composites. These composites were prepared by using 25 wt.% polymeric PCB powder, up to 9% of ethylene propylene rubber (EPR), and PP: balance. The influence of EPR on the structural, thermal, mechanical and rheological properties of PP/PCB/ EPR composites was investigated. While the addition of EPR caused the nucleation of the β crystalline phase of PP, the onset temperature for thermal degradation was found to decrease by 8%. The tensile modulus and strength decreased by 16% and 19%, respectively; and the elongation at break increased by ~71%. The impact strength showed a maximum increase of ~18% at 7 wt.%–9 wt.% EPR content. Various rheological properties were found to be well within the range of processing limits. This novel eco-friendly approach could help utilize significant amounts of polymeric electronic and automotive waste for fabricating valuable polymer composites.

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Urban heat island (UHI) influence on secondary pollutant formation in a tropical humid environment

The combined action of urbanization (change in land use) and increase in vehicular emissions intensifies the urban heat island (UHI) effect in many cities in the developed countries. The urban warming (UHI) enhances heat-stress-related diseases and ozone (O₃) levels due to a photochemical reaction. Even though UHI intensity depends on wind speed, wind direction, and solar flux, the thermodynamic properties of surface materials can accelerate the temperature profiles at the local scale. This mechanism modifies the atmospheric boundary layer (ABL) structure and mixing height in urban regions. These changes further deteriorate the local air quality. In this work, an attempt has been made to understand the interrelationship between air pollution and UHI intensity at selected urban areas located at tropical environment. The characteristics of ambient temperature profiles associated with land use changes in the different microenvironments of Chennai city were simulated using the Envi-Met model. The simulated surface 24-hr average air temperatures (11 m above the ground) for urban background and commercial and residential sites were found to be 30.81 ± 2.06, 31.51 ± 1.87, and 31.33 ± 2.1ºC, respectively. The diurnal variation of UHI intensity was determined by comparing the daytime average air temperatures to the diurnal air temperature for different wind velocity conditions. From the model simulations, we found that wind speed of 0.2 to 5 m/sec aggravates the UHI intensity. Further, the diurnal variation of mixing height was also estimated at the study locations. The estimated lowest mixing height at the residential area was found to be 60 m in the middle of night. During the same period, highest ozone (O₃) concentrations were also recorded at the continuous ambient air quality monitoring station (CAAQMS) located at the residential area.

Implications: An attempt has made to study the diurnal variation of secondary pollution levels in different study regions. This paper focuses mainly on the UHI intensity variations with respect to percentage of land use pattern change in Chennai city, India. The study simulated the area-based land use pattern with local mixing height variations. The relationship between UHI intensity and mixing height provides variations on local air quality.     

Effect of pressure and temperature on the hydropyrolysis of cotton residue

With growing concerns of fossil fuel resources availability and the volatility of crude oil price, it is becoming imperative day by day to utilize the renewable sources of energy in a sustainable, environment friendly and energy efficient manner. India is the world’s second largest producer of cotton after China. India also has several agricultural and forest residues, and cotton residue is one of the most abundant agricultural residues after rice and wheat residues. The hydropyrolysis of cotton residues has been carried out at various pressures (1, 20 and 40 bar) and temperatures (300, 350, 400 and 450 °C). The effects of temperature and pressure have been studied to understand their yield patterns, and it has been observed that 20 bar pressure and 400 °C are the optimum conditions. The thermogravimetric analysis shows that cotton residue has two significant decomposition temperatures. The SEM, XRD patterns and FT-IR spectra clearly indicate the decomposition of the macromolecular structure of the cotton residue and formation of low molecular weight hydrocarbons suitable for various applications.     

Pentachlorophenol dechlorination and simultaneous Cr6+ reduction by Pseudomonas putida SKG-1 MTCC (10510): characterization of PCP dechlorination products, bacterial structure, and functional groups

It is the first report in which a novel psychrotrophic Pseudomonas putida SKG-1 strain was evaluated for simultaneous bioremediation of pentachlorophenol and Cr⁶⁺ under various cultural and nutritional conditions. Pentachlorophenol (PCP) dechlorination products, bacterial structure, and functional groups were characterized by gas chromatography and mass spectrometry (GC–MS), scanning electron microscope and energy dispersive X-ray spectroscopy (SEM–EDS), and Fourier-transform infrared (FTIR) techniques. The strain was extremely tolerant to excessively higher individual concentration of PCP (1,400 mg l^?1) and Cr⁶⁺ (4,300 mg l^?1). Increasing concentration of PCP and Cr⁶⁺ exerted inhibitory effect on bacterial growth and toxicants’ removal. The strain exhibited growth, and concomitantly remediated both the pollutants simultaneously over a broad pH (7.0–9.0) and temperature (28–32 °C) range; maximum growth, PCP dechlorination (87.5 %), and Cr⁶⁺ removal (80.0 %) occurred at optimum pH 8.0 and 30 °C (from initial PCP 100 mg l^?1 and Cr⁶⁺ 500 mg l^?1) under shaking (150 rpm) within 72 h incubation. Optimization of agitation (125 rpm) and aeration (0.4 vvm) in bioreactor further enhanced PCP dechlorination by ~10 % and Cr⁶⁺ removal by 2 %. A direct correlation existed between growth and bioremediation of both the toxicants. Among other heavy metals, mercury exerted maximum and cobalt minimum inhibitory effect on PCP dechlorination and Cr⁶⁺ removal. Chromate reductase activity was mainly associated with the supernatant and cytosolic fraction of bacterial cells. GC–MS analysis revealed the formation of tetrachloro-p-hydroquinone, 2,4,6-trichlorophenol, and 2,6-dichlorophenol as PCP dechlorination products. FTIR spectrometry indicated likely involvement of carbonyl and amide groups in Cr³⁺ adsorption, and SEM–EDS showed the presence of chromium on P. putida surface. Thus, our promising isolate can be ecofriendly employed for biotreatment of various industrial wastes contaminated with high PCP and Cr⁶⁺ concentrations.     

Artificial neural network based carbon monoxide persistence models for episodic urban air quality management

This paper describes the development of artificial neural network (ANN) based carbon monoxide (CO) persistence (ANNCOP) models to forecast 8-h average CO concentration using 1-h maximum predicted CO data for the critical (winter) period (November–March). The models have been developed for three 8-h groupings of 10 p.m. to 6 a.m., 6 a.m. to 2 p.m. and 2–10 p.m., at two air quality control regions (AQCRs) in Delhi city, representing an urban intersection and an arterial road consisting heterogeneous traffic flows. The result indicates that time grouping of 2–10 pm is dominantly affected by inversion conditions and peak traffic flow. The ANNCOP model corresponding to this grouping predicts the 8-h average CO concentrations within the accuracy range of 68–71%. The CO persistence values derived from ANNCOP model are comparable with the persistence values as suggested by the Environmental Protection Agency (EPA), USA. This work demonstrates that ANN based model is capable of describing winter period CO persistence phenomena.