Studies on soil parameters of sediments from the River Ganga phosphorus mobilization,interactions with sediment and the phosphorus cycle

Large quantities of sediment are transported by the River Ganga (The Ganges) particularly In its deltaic region. Attempts have been made to study the physicochemical parameters of the bottom sediments of the River Ganga at various depths at Kamarhati and along the banks of the River Ganga in the lower deltaic region. The results give vital information regarding the pollution load carried by the river and the enrichment of its sediments with nutrients such as P, N and other substances such as C and S (as sulphates). The mobilization of the P, N, C and S (as sulphates) in the sediments is compared with their natural abundance. The enrichment of the river beds with P, the interaction of the sediment and the characteristics of the sediments are ascertained. Some aspects of the phosphorus cycle and its importance are also discussed. The recycling and reuse of sediments for agricultural purposes have been proposed in order to restore ecological imbalances due to nutrient loss.Mrs M. Chattopadhyay (née Ray) and D. Mukherjee are both post-doctorate ex-senior research scholars within the Department of Chemistry, Kalyani University, where Professor S.C. Lahiri was until recently head of department. Mr S.K. Bhattacharya is director of the Ganga Action Plan Sector, Calcutta Metropolitan Development Authority, Unnayan Bhavan (1st floor), Salt Lake, Calcutta 700 091, India. The information given in this paper is supplementary to that provided by certain of the same authors inThe Environmentalist 13(3), 199–210.     

An experimental study to evaluate musculoskeletal disorders and postural stress of female craftworkers adopting different sitting postures

This study aimed to evaluate musculoskeletal disorders (MSDs) and postural stress among female craftworkers. The study was carried out on 75 adult female craftworkers in different districts of West Bengal. The prevalence of MSDs, body part discomfort (BPD) rating and body joint angles of the workers were evaluated with standard methods. Electromyography (EMG) of the shoulder and back muscles was recorded with the BIOPAC system. The prevalence of MSDs, BPD rating and deviation of joint angle were comparatively lower in the case of sitting on the floor with folded legs than squatting and sitting on the floor with stretched legs postures. The EMG and rms values of the shoulder and back muscles were comparatively lower in this posture. Therefore, it was concluded that sitting on the floor with folded legs was less hazardous and it imposed less postural stress in comparison to other sitting postures.     

Look before you leap: is risk of injury a foraging cost?

Theory states that an optimal forager should exploit a patch so long as its harvest rate of resources from the patch exceeds its energetic, predation, and missed opportunity costs for foraging. However, for many foragers, predation is not the only source of danger they face while foraging. Foragers also face the risk of injuring themselves. To test whether risk of injury gives rise to a foraging cost, we offered red foxes pairs of depletable resource patches in which they experienced diminishing returns. The resource patches were identical in all respects, save for the risk of injury. In response, the foxes exploited the safe patches more intensively. They foraged for a longer time and also removed more food (i.e., had lower giving up densities) in the safe patches compared to the risky patches. Although they never sustained injury, video footage revealed that the foxes used greater care while foraging from the risky patches and removed food at a slower rate. Furthermore, an increase in their hunger state led foxes to allocate more time to foraging from the risky patches, thereby exposing themselves to higher risks. Our results suggest that foxes treat risk of injury as a foraging cost and use time allocation and daring—the willingness to risk injury—as tools for managing their risk of injury while foraging. This is the first study, to our knowledge, which explicitly tests and shows that risk of injury is indeed a foraging cost. While nearly all foragers may face an injury cost of foraging, we suggest that this cost will be largest and most important for predators.     

Residual behavior and risk assessment of flubendiamide on tomato at different agro-climatic conditions in India

Supervised field trials were conducted at four different agro-climatic zones in India to evaluate the dissipation pattern and risk assessment of flubendiamide on tomato. Flubendiamide 480 SC was sprayed on tomato at 48 and 96 g active ingredient (a.i.) ha^?1. Samples of tomato fruits were drawn at 0, 1, 3, 5, 7, 10, 15, and 20 days after treatment. Quantification of residues was done on a high-performance liquid chromatography (HPLC) device with a photo diode array detector. The limit of quantification (LOQ) of this method was found to be 0.01 mg kg^?1 while limit of detection (LOD) being 0.003 mg kg^?1. Residues of flubendiamide were found below the determination limit of 0.01 mg kg^?1 in 20 days at both the dosages in all the locations. The half-life of flubendiamide at an application rate of 48 g a.i.?ha^?1 varied from 0.33 to 3.28 days and at 48-g a.i. ranged from 1.21 to 3.00 days. On the basis of data generated under the All India Network Project on Pesticide Residues, a preharvest interval (PHI) of 1 day has been recommended, and the flubendiamide 480 SC has been registered for its use on tomato by the Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of flubendiamide on tomato has been fixed by the Ministry of Health and Family Welfare, Government of India under Food Safety Standard Authority of India, as 0.07 μg g^?1 after its risk assessment.     

Identification of erosional and inundation hazard zones in Ken?CBetwa river linking area, India, using remote sensing and GIS

Ken-Betwa river link is one of the pilot projects of the Inter Linking of Rivers program of Government of India in Bundelkhand Region. It will connect the Ken and Betwa rivers through a system of dams, reservoirs, and canals to provide storage for excess rainfall during the monsoon season and avoid floods. The main objective of this study is to identify erosional and inundation prone zones of Ken-Betwa river linking site in India using remote sensing and geographic information system tools. In this study, Landsat Thematic Mapper data of year 2005, digital elevation model from the Shuttle Radar Topographic Mission, and other ancillary data were analyzed to create various thematic maps viz. geomorphology, land use/land cover, NDVI, geology, soil, drainage density, elevation, slope, and rainfall. The integrated thematic maps were used for hazard zonation. This is based on categorizing the different hydrological and geomorphological processes influencing the inundation and erosion intensity. Result shows that the southern part of the study area which lies in Panna district of Madhya Pradesh, India, is more vulnerable than the other areas.     

A comparative study of biopolymers and alum in the separation and recovery of pulp fibres from paper mill effluent by flocculation

Recovery of cellulose fibres from paper mill effluent has been studied using common polysacchatides or biopolymers such as Guar gum, Xanthan gum and Locust bean gum as flocculent. Guar gum is commonly used in sizing paper and routinely used in paper making. The results have been compared with the performance of alum, which is a common coagulant and a key ingredient of the paper industry. Guar gum recovered about 3.86 mg/L of fibre and was most effective among the biopolyrners. Settling velocity distribution curves demonstrated that Guar gum was able to settle the fibres faster than the other biopolymers; however, alum displayed the highest particle removal rate than all the biopolymers at any of the settling velocities. Alum, Guar gum, Xanthan gum and Locust bean gum removed 97.46%, 94.68%, 92.39% and 92.46% turbidity of raw effluent at a settling velocity of 0.5 cm/min, respectively. The conditions for obtaining the lowest sludge volume index such as pH, dose and mixing speed were optimised for guar gum which was the most effective among the biopolymers. Response surface methodology was used to design all experiments, and an optimum operational setting was proposed. The test results indicate similar performance of alum and Guar gum in terms of fioc settling velocities and sludge volume index. Since Guar gum is a plant derived natural substance, it is environmentally benign and offers a green treatment option to the paper mills for pulp recycling.     

Fly ash scrubbing in a novel dual flow scrubber

Scrubbers are used as particulate emission control devices with the increase in stringency of old regulations or promulgation of new regulations. Scrubbing of fly ash in a novel dual flow scrubber, i.e., one water filled bubble section and one section with water-spray, is reported in this article. The presented system included a tapered section in order to achieve the bubble regime. On the other hand, a two-phase critical flow atomizer was used for the generation of spray regime with high degree of spray uniformity. Experiments were carried out for studying the behavior of the system in terms of various pertinent variables. The fly ash removal mechanism was explained in terms of various physical interactions. Electrostatic effect was found to have an insignificant influence on the collection efficiency of fly ash. The removal efficiency was found to decrease with the increase in inlet fly ash loading in the bubble section while it was increased in the spray section. A compromise must, therefore, be struck while operating the scrubber for achieving the desired performance. The effects of other operating variables studied on the removal efficiency remained similar in the regimes under investigation. The combined effect was, however, that the spray regime was dominating. Experimentation also revealed that the bubble section collected particles down to 20 microm size. Detailed experimentation revealed that almost 100% removal efficiency (zero penetration) of fly ash could be achieved in the dual flow scrubber at a QL/QG ratio of 3.0 m3/1000 ACM (actual cubic meter). Almost zero penetration of fly ash particles, clearly demonstrated that the dual flow scrubber with its staging operations met with the stricter emission regulations for particulate matter. Selection of any particulate control device is intrinsically related to the performance as a function of various pertinent variables of the system. Correlations were, therefore, put forward for the prediction of the performances of the bubble and the spray sections in terms of various pertinent variables of the system. The overall removal efficiency achievable in the dual flow scrubber was predicted with the help of these correlations. The predicted values were in excellent agreement with the experimental values (well within +/-5.0% deviation). Comparison of the performance of the present system with the existing systems indicated that the bubble and spray sections either alone or in combination (as in a dual flow scrubber), was energy and efficiency-wise much better than the existing systems. The novelty of the system is also described.     

Examining Environmental Kuznets Curve for river effluents in India

This study aims to determine the trade-off between river pollution and the growth of the economy in the context of India using the concept of Environmental Kuznets Curve (EKC). According to EKC theory, environmental pressure tends to rise faster than income growth in the early stages of economic development and then declines in the later stages with further economic growth. The present study has used the cross-sectional time series data for river pollutants of Biochemical Oxygen Demand (BOD) and Dissolved Hydrogen Ions (PH) across various states of India for the period 1990–1991 to 2005–2006. This study shows why the conventional EKC model is not sufficient to ascertain the declining path of pollution as the economy grows in the second stage. The paper uses the modified EKC theory where the EKC curve is proposed to have 2 turning points. Our results indicated ‘tilted-S shaped’ relationship which contradicts EKC in the early stages. Most of the regions that were studied have crossed the first turning point but are still to cross the second turning point, which means that there will be an ascent in the pollution level in the future. This calls for more stringent environment policies complementing the desired growth path.     

From Bathymetry to Bioshields: A Review of Post-Tsunami Ecological Research in India and its Implications for Policy

More than half a decade has passed since the December 26th 2004 tsunami hit the Indian coast leaving a trail of ecological, economic and human destruction in its wake. We reviewed the coastal ecological research carried out in India in the light of the tsunami. In addition, we also briefly reviewed the ecological research in other tsunami affected countries in Asia namely Sri Lanka, Indonesia, Thailand and Maldives in order to provide a broader perspective of ecological research after tsunami. A basic search in ISI Web of Knowledge using keywords “tsunami” and “India” resulted in 127 peer reviewed journal articles, of which 39 articles were pertaining to ecological sciences. In comparison, Sri Lanka, Indonesia, Thailand and Maldives had, respectively, eight, four, 21 and two articles pertaining to ecology. In India, bioshields received the major share of scientific interest (14 out of 39) while only one study (each) was dedicated to corals, seagrasses, seaweeds and meiofauna, pointing to the paucity of research attention dedicated to these critical ecosystems. We noted that very few interdisciplinary studies looked at linkages between pure/applied sciences and the social sciences in India. In addition, there appears to be little correlation between the limited research that was done and its influence on policy in India. This review points to gap areas in ecological research in India and highlights the lessons learnt from research in other tsunami-affected countries. It also provides guidance on the links between science and policy that are required for effective coastal zone management.     

Genotoxicity of titanium dioxide (TiO2) nanoparticles at two trophic levels: plant and human lymphocytes

The environmental fate and behaviour of titanium dioxide (TiO(2)) nanoparticles is a rapidly expanding area of research. There is a paucity of information regarding toxic effect of TiO(2) nanoparticles in plants and to certain extent in humans. The present study focuses on the effect of exposure of TiO(2) nanoparticles in two trophic levels, plant and human lymphocytes. The genotoxicity of TiO(2) nanoparticles was evaluated using classical genotoxic endpoints, comet assay and DNA laddering technique. DNA damaging potential of TiO(2) nanoparticles in Allium cepa and Nicotiana tabacum as representative of plant system could be confirmed in the comet assay and DNA laddering experiments. In Allium micronuclei and chromosomal aberrations correlated with the reduction in root growth. We detected increased level of malondialdehyde (MDA) concentration at 4mM (0.9 μM) treatment dose of TiO(2) nanoparticles in Allium cepa. This indicated that lipid peroxidation could be involved as one of the mechanism leading to DNA damage. A comparative study of the cytotoxic and genotoxic potential of TiO(2) nanoparticles and bulk TiO(2) particles in human lymphocytes also reveal interesting results. While TiO(2) nanoparticles were found to be genotoxic at a low dose of 0.25 mM followed by a decrease in extent of DNA damage at higher concentrations; bulk TiO(2) particles reveal a more or less dose dependent effect, genotoxic only at dose 1.25 mM and above. The study thus confirms the genotoxic potential of TiO(2) nanoparticles in both plant and human lymphocytes.