Are the existing guideline values adequate to protect soil health from inorganic mercury contamination?

© 2018 Elsevier Ltd Currently, data that guide safe concentration ranges for inorganic mercury in the soil are lacking and subsequently, threaten soil health. In the present study, a species sensitivity distribution (SSD) approach was applied to estimate critical mercury concentration that has little (HC 5 ) or no effect (PNEC) on soil biota. Recently published terrestrial toxicity data were incorporated in the approach. Considering total mercury content in soils, the estimated HC 5 was 0.6 mg/kg, and the PNEC was 0.12–0.6 mg/kg. Whereas, when only water-soluble mercury fractions were considered, these values were 0.04 mg/kg and 0.008–0.04 mg/kg, respectively

Effect of Nitrogen Rates and Foliar Spray of Micronutrients on Growth and Yield of Sesame (Sesamum indicum L.)

To find out optimum nitrogen (N) and micronutrients (MNs) doses for the growth and yield of sesame the experiment was undertaken at Sher-e-Bangla Agricultural University Research field, Dhaka, during April to July 2013 with three replications in a randomized complete block design (RCBD). Three different N levels viz. N0= without N, N1= 60 kg h-1, N2=120 kg h-1 and four micronutrients (MNs) levels viz. M0= without MNs, M1= 50 ppm MNs, M2= 100 ppm and M3= 150 ppm MNs. The N significantly increased morphological characters - plant height, number of  leaves plant-1, branch number plant-1, fresh and dry weight of shoot and root; yield contributing characters-  number of pod plant-1, pod diameter, pod length, seed weight plant-1, seed weight plot-1 compared to control (N0). The rate of application of N 60 kg ha-1 produced the highest seed yield (1.21 t ha-1) which is consisting with most of the vegetative growth of sesame. Foliar application of different concentration of micronutrients also improved the morphological characters and seed yield of sesame as N. Interestingly 1000-seed weight did not show any significant differences with both  N and micronutrients. The maximum number of pod plant-1, pod diameter, pod length, seed weight plant-1, seed yield (1.14 tha-1) significantly increased with 150 ppm micronutrients. Therefore, this experimental results suggest that the use of 60 kg Nha-1 and 150 ppm micronutrients have produced highest seed yield of sesame by adjusting in plant morphological characters and yield contributing characters of sesame

Bioremediation of mercury: not properly exploited in contaminated soils!

© 2017, Springer-Verlag Berlin Heidelberg. Contamination of land and water caused by heavy metal mercury (Hg) poses a serious threat to biota worldwide. The seriousness of toxicity of this neurotoxin is characterized by its ability to augment in food chains and bind to thiol groups in living tissue. Therefore, different remediation approaches have been implemented to rehabilitate Hg-contaminated sites. Bioremediation is considered as cheaper and greener technology than the conventional physico-chemical means. Large-scale use of Hg-volatilizing bacteria are used to clean up Hg-contaminated waters, but there is no such approach to remediate Hg-contaminated soils. This review focuses on recent uses of Hg-resistant bacteria in bioremediation of mercury-contaminated sites, limitation and advantages of this approach, and identifies the gaps in existing research

Current development and future perspective on natural jute fibers and their biocomposites

The increasing trend of the use of synthetic products may result in an increased level of pollution affecting both the environment and living organisms. Therefore, from the sustainability point of view, natural, renewable and biodegradable materials are urgently needed to replace environmentally harmful synthetic materials. Jute, one of the natural fibers, plays a vital role in developing composite materials that showed potential in a variety of applications such as household, automotive and medical appliances. This paper first reviews the characterization and performance of jute fibers. Subsequently, the main focus is shifted towards research advancements in enhancing physical, mechanical, thermal and tribological properties of the polymeric materials (i.e., synthetic or biobased and thermoplastic or thermoset plastic) reinforced with jute fibers in a variety of forms such as particle, short fiber or woven fabric. It is understood that the physio-mechanical properties of jute-polymer composites largely vary based on the fiber processing and treatment, fiber shape and/or size, fabrication processes, fiber volume fraction, layering sequence within the matrix, interaction of the fiber with the matrix and the matrix materials used. Furthermore, the emerging research on jute fiber, such as nanomaterials from jute, bioplastic packaging, heavy metal absorption, electronics, energy device or medical applications and development of jute fiber composites with 3D printing, is explored. Finally, the key challenges for jute and its derivative products in gaining commercial successes have been highlighted and potential future directions are discussed

Framework for Environmentally Sustainable Fashion and Textile Production to achieve United Nation (UN) Sustainable Development Goal (SDG) 12

A framework with three key actions - identify (I), act (A), and evaluate (E) to achieve complete environmental sustainability in fashion and textile production in line with SDG 12– has been developed as a part of a Global Challenge Research Fund (GCRF) project. Called as the ‘I-A-E framework’, it emphasises more on zero or near-zero waste generation at source and incorporating sustainability thinking in material and process selections, rather than post-production waste management after generating huge amounts of wastes and effluents. The first step involves ‘identifying’ present scenarios and points of action in context of resource consumption, air pollution and greenhouse gas emissions, water pollution, and solid waste generation in product development and production. The next step is to ‘act’ for sustainable development, which includes - incorporating a zero-waste philosophy during production, incorporating sustainability thinking into material selection and incorporating sustainability into production process, incorporating sustainability in resource and waste management. The third component of the framework is to ‘evaluate’ to celebrate and move forward by checking the eco-indices to amend targets or set new ones. This new framework was validated through stakeholders’ workshops and roundtable discussion. It is an easy-to-follow toolkit that the fashion and textile industry will be able to implement into their product development and production activities

A simple spectrophotometric method for rapid quantitative screening of arsenic bio-transforming bacteria

© 2020 A simple spectrophotometric technique for inorganic arsenic speciation of known total arsenic has been developed for application in quantitative screening of arsenite-oxidizing and arsenate-reducing bacteria from the wide range of environmental isolates. The technique is based on the spectrophotometric absorbance measurement of the color intensity in the arsenic and potassium permanganate mixture. Since arsenate does not react with potassium permanganate, the intensity of color decreases proportionately with the increasing concentration of arsenite in the total arsenic. The speciation method can be used over a pH range of 4–9. The validity of the results obtained from this spectrophotometric method was confirmed with the Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometry (LC-ICP-MS). This method has great potential for the screening of arsenite-oxidizing bacteria

As(V) removal from aqueous solution using a low-cost adsorbent coir pith ash: Equilibrium and kinetic study

© 2017 Elsevier B.V. In this study, the adsorptive removal of As(V) from aqueous solution by using a low-cost adsorbent coir pith ash (CPA) was analysed in a batch system. The adsorption capacity of CPA was investigated under different process parameters, these being pH, adsorbent dose, initial As(V) concentration and contact time. The CPA was found to adsorb As(V) over the initial solution pH range of 2–12, and the best adsorbent dose was 5 g/L. Adsorption kinetics data were best fitted to the pseudo-second-order kinetic model. The Langmuir and Dubinin–Radushkevich (D–R) isotherms represented the adsorption equilibrium data very well. The maximum adsorption capacity was 36.5 mg/g as per Langmuir isotherm at room temperature (25 °C). The mean free energy (8.64 kJ/mol) obtained from the D–R isotherm model revealed that the type of adsorption depends on the ion-exchange mechanism. The results showed that adsorbent CPA has great potential for removing As(V) from contaminated water