Concentrations,input prediction and probabilistic biological risk assessment of polycyclic aromatic hydrocarbons (PAHs) along Gujarat coastline

A comprehensive investigation was conducted in order to assess the levels of PAHs, their input prediction and potential risks to bacterial abundance and human health along Gujarat coastline. A total of 40 sediment samples were collected at quarterly intervals within a year from two contaminated sites—Alang-Sosiya Shipbreaking Yard (ASSBRY) and Navlakhi Port (NAV), situated at Gulf of Khambhat and Gulf of Kutch, respectively. The concentration of ΣPAHs ranged from 408.00 to 54240.45 ng g^?1 dw, indicating heavy pollution of PAHs at both the contaminated sites. Furthermore, isomeric ratios and principal component analysis have revealed that inputs of PAHs at both contaminated sites were mixed-pyrogenic and petrogenic. Pearson co-relation test and regression analysis have disclosed Nap, Acel and Phe as major predictors for bacterial abundance at both contaminated sites. Significantly, cancer risk assessment of the PAHs has been exercised based on incremental lifetime cancer risks. Overall, index of cancer risk of PAHs for ASSBRY and NAV ranged from 4.11 × 10^?6–2.11 × 10^?5 and 9.08 × 10^?6–4.50 × 10^?3 indicating higher cancer risk at NAV compared to ASSBRY. The present findings provide baseline information that may help in developing advanced bioremediation and bioleaching strategies to minimize biological risk.     

Efficiency of Modified H2S Test for Detection of Faecal Contamination in Water

Faecal contamination is a major causative factor for incidence of water borne infectious diseases. Certain hydrogen sulfide (H₂S) producing enteric bacteria such as Salmonella sp. and Citrobacter sp., assosiated with coliforms, have been considered for rapid detection of recent faecal contamination in water. The basic H₂S test medium, modified by adding 0.25 gm/L of L-cystine HCl, was examined for its efficiency with 90 water samples collected from 40 pipe supplies, 20 open wells, 15 hand pumps and 15 different surface water bodies (river, streams and ponds). Sterilized modified culture medium in glass vials was inoculated with 100 mL of each sample and incubated at 20, 25, 30, 35 and 44 ^∘C for 18, 24, 42, 48, 66 and 72 h. Blackening of content in incubated vials was considered positive. For comparison, most probable number (MPN) of coliform and faecal coliform per 100 mL was also estimated in each sample by multiple tube fermentation (MTF) method. H₂S positive result was exhibited by 78% of samples. Coliform (> 10) and faecal coliform/100 mL were also detected in 59% of samples. Maximum H₂S positive results (100%) were found with well and surface water samples incubated at 30, 35 and 44 ^∘C for 18 h. Coliform (> 10) and faecal coliform/100 mL were also detected in most of these samples. Pipe supplies (60%) and hand pumps (73%) also exhibited considerable H₂S production. Coliforms and faecal coliforms were also found in significant number of these samples. Thus, the modified H₂S test may prove a useful alternative indicator of faecal contamination for water quality surveillance and screening of large number of water samples in short duration, particularly during any outbreak of water borne disease among rural population.     

Riverine pollution in some northern and north eastern states of india

Water samples from 30 rivers in northern and north-eastern hilly states of India were analysed for bacteriological and physicochemical parameters along with metals and pesticide residues. It was found that 34% of samples had >50 coliforms/100 ml, while 24% of samples demonstrated >50 thermotolerant (faecal) coliforms/100 ml. Among the metals, iron was found to be above maximum permissible limits in the rivers of all the states, while manganese was found to be above the maximum permissible limit in the rivers of Tripura and some northern states. Zinc, lead, nickel, chromium, copper, cobalt and cadmium plus physicochemical parameters and residual pesticides, however, were within their maximum permissible limits.     

Use of activated Chromolaena odorata biomass for the removal of crystal violet from aqueous solution: kinetic,equilibrium, and thermodynamic study

Environmental Science and Pollution Research - In the present study, biomass from the Chromolaena odorata plant’s stem was activated using sulfuric acid to adsorb crystal violet (CV) dye. The...     

UVR-induced toxicity of sludge and polycyclic aromatic hydrocarbons on seed germination and seedling growth of Triticum aestivum L.

The depletion of the ozone layer and enhancement of solar radiation may exert an adverse influence on the ecosystem. Phototoxicity of sludge and polycyclic aromatic hydrocarbons (PAHs) under ultraviolet radiation (UVR) to seedling was studied. Seeds of wheat (Triticum aestivum) were planted in sludge and PAHs (anthracene (An), benzo(a)pyrene (BaP) and pyrene (Py)) with and without UVR. Toxicity of sludge increased in the presence of UVR in wheat. UVB radiation was found to be more hazardous than UVA radiation. Results demonstrated that An, BaP and Py induced phototoxicity at various concentrations (1–10?µg/mL) under UVA (1.5?mW/cm²) or UVB (1.08?J/cm²) exposure. The pattern of phototoxicity was An?>?Py?>?BaP to shoot length, root length, and fresh weight; chlorophyll, protein content, enzyme activity of catalase and α-amylase were reduced while the activity of superoxide dismutase and starch was enhanced. Reduction in seedling growth and biochemical parameters may be related to less photosynthesis, less nutritional uptake, and distortion of root cap. Thus, the synergistic effect may be due to alterations in photosynthesis, phytohormones, or nutritional uptake.     

Evaluation of different CHP options for refinery integration in the context of a low carbon future

This study presents a comparison of different concepts for delivering combined heat and power (CHP) to a refinery in Norway. A reference case of producing high pressure steam from natural gas in boilers and electricity in a combined cycle power plant, is compared to a: (1) natural gas fueled CHP without any CO₂ capture; (2) hydrogen fueled CHP with hydrogen produced from steam methane reforming (SMR); (3) hydrogen fueled CHP with hydrogen produced from autothermal reforming (ATR); and finally (4) natural gas fueled CHP with postcombustion CO₂ removal. The options are compared on the basis of first law efficiency, emissions of CO₂ and a simplified cash flow evaluation. Results show that in terms of efficiency the standard natural gas fueled CHP performs better than the reference case as well as the options with carbon capture. The low carbon options in turn offer lower emissions of greenhouse gases while maintaining the same efficiency as the reference case. The cash flow analysis shows that for any option, a certain mix of prices is required to produce a positive cash flow. As expected, the relationship between natural gas price and electricity price affects all options. Also the value of heat and CO₂ emissions plays an important role.     

Evaluation of bactericidal efficacy of silver ions on Escherichia coli for drinking water disinfection

Purpose

The purpose of this study is the development of a suitable process for the disinfection of drinking water by evaluating bactericidal efficacy of silver ions from silver electrodes.

Methods

A prototype of a silver ioniser with silver electrodes and control unit has been fabricated. Silver ions from silver electrodes in water samples were estimated with an atomic absorption spectrophotometer. A fresh culture of Escherichia coli (1.75?×?10³ c.f.u./ml) was exposed to 1, 2, 5, 10 and 20?ppb of silver ions in 100?ml of autoclaved tap water for 60?min. The effect of different pH and temperatures on bactericidal efficacy was observed at constant silver ion concentration (5?ppb) and contact time of 30?min.

Results

The maximum bactericidal activity (100%) was observed at 20?ppb of silver ion concentration indicating total disinfection after 20?min while minimum bactericidal activity (25%) was observed after 10?min at 01?ppb of silver ions. Likewise, 100% bactericidal activity was noticed with 2, 5 and 10?ppb of silver ions after 60, 50 and 40?min, respectively. Bactericidal activity at pH?5, 6, 7, 8 and 9 was observed at 79.9%, 79.8%, 80.5%, 100% and 100%, respectively, whereas it was 80.4%, 88.3%, 100%, 100% and 100% at 10°C, 20°C, 30°C, 40°C and 50°C, respectively.

Conclusion

The findings of this study revealed that very low concentrations of silver ions at pH?8?C9 and temperature >20°C have bactericidal efficacy for total disinfection of drinking water. Silver ionisation is suitable for water disinfection and an appropriate alternative to chlorination which forms carcinogenic disinfection by-products.     

Activity Accounting Technique for Environmental Noise Assessment in Mechanized Surface Mining

The authors have developed the Activity Accounting Technique for predicting far field noise levels due to operation of specific set of mining machinery. The technique is based on the breaking down of the mining operations into a number of activities and establishing their duration and average location. By estimating the noise levels due to these activities, the overall noise field near a surface mine can be predicted. Experiments were undertaken at a quarry to validate the model developed based on this technique. Results of these experiments are discussed in this paper. The Activity Accounting Technique has the scope of elaborate application for prediction of environmental noise near mining sites. In a system where the activities involved and their duration can be estimated one can develop a noise quality prediction model based on near field spectrum of the sound pressure levels due to the activities. However, this method will be more useful if an acoustic database can be evolved for all the possible activities for different alternative equipment system.     

Statistical inferences from measured data on concentrations of naturally occurring radon,thoron, and decay products in Kumaun Himalayan belt

Environmental Science and Pollution Research - Regional averages of radon, thoron, and associated decay product concentration are reported to be higher than their respective global averages in...     

Effective oil removal from water by magnetically driven superhydrophobic and oleophilic magnetic titania nanotubes

Development of efficient techniques to combat the harmful effects of oil spill is an emerging field, where fabrication of new sorbents for selective removal of oil has become a hot topic for environmental scientists. The present study reports the preparation of superhydrophobic/oleophilic magnetic titania nanotubes via a facile hydrothermal method, followed by the treatment with octadecylamine, as potential magnetically driven sorbent for selective removal of oil from water surface. The magnetic nature (superparamagnetism at 300 K) of the nanotubes enabled magnetic removal of the oil-sorbed material from water surface. Wettability test of the material depicted a static water contact angle of 166 ± 1°, indicating its superhydrophobic character. Oil uptake experiments and contact angle measurements revealed its superoleophilicity with maximum oil sorption capacity >1.5 g/g for a variety of oils. In addition to the ease of magnetic removal, the nanotubes possess sufficient buoyancy, high selectivity, and quick rate of oil uptake and is more than five times reusable.