Thermal treatments are the primary technologies used to remove persistent organic pollutants from contaminated solids. The high energy consumption during continuous heating, required cost for treating the exhaust gas, and potential formation of secondary pollutants during combustion have prevented their implementation. A novel successive self-propagated sintering process was proposed for removing polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) from contaminated solids in a low-cost and environmentally friendly way. Nine laboratory-scale experiments involving different initial concentrations of pollutants and solid compositions were performed. Almost all PCBs (>99 %) and HCB (>97 %) were removed from solids under constant experimental conditions. Varying initial concentrations of PCBs and HCB in the contaminated solids did not influence the removal efficiency of the pollutants; however, the degradation efficiency of pollutants increased as their initial concentrations increased. Although varying levels of PCDD/Fs were detected in the effluent gas, they were all within the emission standard limit.

Catharanthus roseus L. plants were grown under ambient (375 ± 30 ppm) and elevated (560 ± 25 ppm) concentrations of atmospheric CO₂at different rates of N supply (without supplemental N, 0 kg N ha⁻¹; recommended N, 50 kg N ha⁻¹; and double recommended N, 100 kg N ha⁻¹) in open top chambers under field condition. Elevated CO₂significantly increased photosynthetic pigments, photosynthetic efficiency, and organic carbon content in leaves at recommended (RN) and double recommended N (DRN), while significantly decreased total nitrogen content in without supplemental N (WSN). Activities of superoxide dismutase, catalase, and ascorbate peroxidase were declined, while glutathione reductase, peroxidase, and phenylalanine-ammonia lyase were stimulated under elevated CO₂. However, the responses of the above enzymes were modified with different rates of N supply. Elevated CO₂significantly reduced superoxide production rate, hydrogen peroxide, and malondialdehyde contents in RN and DRN. Compared with ambient, total alkaloids content increased maximally at recommended level of N, while total phenolics in WSN under elevated CO₂. Elevated CO₂stimulated growth of plants by increasing plant height and numbers of branches and leaves, and the magnitude of increment were maximum in DRN. The study suggests that elevated CO₂has positively affected plants by increasing growth and alkaloids production and reducing the level of oxidative stress. However, the positive effects of elevated CO₂were comparatively lesser in plants grown under limited N availability than in moderate and higher N availability. Furthermore, the excess N supply in DRN has stimulated the growth but not the alkaloids production under elevated CO₂.

This paper is focused on the selection of cosolvents in the remediation of contaminated soils. The aim of this study was to investigate the combined effects of Triton X-100 (TX-100) and different cosolvents on the solubilization behavior of 4,4′-dibromodiphenyl ether (BDE-15) and the washing of BDE-15 from a contaminated soil.¹H NMR spectroscopies were used to elucidate the interactions among TX-100, cosolvents, and BDE-15 in aqueous micellar solution. Results showed that the solubility of BDE-15 was enhanced by the observed synergism among TX-100, BDE-15, and cosolvents, and the TX-100/dimethyl sulfoxide (DMSO) system exhibited the best performance in the solubilization of BDE-15. Similar synergism was further evidenced in the washing of BDE-15 from a contaminated soil. With 10 % (v/v) DMSO and 6.4 mM TX-100 solution added, considerable synergistic effect was achieved in TX-100/DMSO system, leading to the highest removal efficiency (92.9 %) of BDE-15 from the soil, relative to that of 67.3 % with TX-100 alone at the same concentration.

To our knowledge, this is the first report into trace elements accumulation in tissues of the short sea snake (Lapemis curtus). Lead (Pb), cadmium (Cd), copper (Cu), vanadium (V), nickel (Ni), and zinc (Zn) were determined in the kidney, liver, skin, and muscle tissues of short sea snake, L. curtus, from the Strait of Hormuz during October 2011. Skins generally displayed the lowest trace element burdens. Kidneys displayed the highest Pb, Cd, V, Ni, and Cu mean concentrations (0.89, 0.04, 1.66, 6.22, and 20.23 μg g⁻¹ dry weight, respectively), while muscle exhibited the highest Zn levels (493.32 μg g⁻¹ dry weight). Concentration ranges of the selected trace elements were compared with those reported in other studies. Data presented here may be considered as a baseline for further ecotoxicological studies in sea snakes.

Rapid development of nanotechnology in recent years has raised concerns about nanoparticle (NPs) release into the environment and its adverse effects on living organisms. The present study is the first comprehensive report on the anatomical and ultrastructural changes of a variety of cells after long-term exposure of plant to NPs or bulk material particles (BPs). Light and electron microscopy revealed some anatomical and ultrastructural modifications of the different types of cell in the root and leaf, induced by both types of treatment. Zinc oxide (ZnO) BPs-induced modifications were surprisingly more than those induced by ZnO NPs. The modifications induced by ZnO BPs or ZnO NPs were almost similar to those induced by excess Zn. Zn content of the root and leaf of both ZnO NPs- and ZnO BPs-treated plants was severely increased, where the increase was greater in the plants treated with ZnO BPs. Overall, these results indicate that the modifications induced by ZnO particles can be attributed, at least partly, to the Zn²⁺ dissolution by ZnO particles rather than their absorption by root and their subsequent effects.

Water quality trading (WQT) is supported by the US Environmental Protection Agency (USEPA) under the framework of its total maximum daily load (TMDL) program. An innovative approach is presented in this paper that proposes post-TMDL trade by calculating pollutant rights for each pollutant source within a watershed. Several water quality trading programs are currently operating in the USA with an objective to achieve overall pollutant reduction impacts that are equivalent or better than TMDL scenarios. These programs use trading ratios for establishing water quality equivalence among pollutant reductions. The inbuilt uncertainty in modeling the effects of pollutants in a watershed from both the point and nonpoint sources on receiving waterbodies makes WQT very difficult. A higher trading ratio carries with it increased mitigation costs, but cannot ensure the attainment of the required water quality with certainty. The selection of an applicable trading ratio, therefore, is not a simple process. The proposed approach uses an Economic TMDL optimization model that determines an economic pollutant reduction scenario that can be compared with actual TMDL allocations to calculate selling/purchasing rights for each contributing source. The methodology is presented using the established TMDLs for the bacteria (fecal coliform) impaired Muddy Creek subwatershed WAR1 in Rockingham County, Virginia, USA. Case study results show that an environmentally and economically superior trading scenario can be realized by using Economic TMDL model or any similar model that considers the cost of TMDL allocations.

The distribution characteristics of pollutants released at varied rates and different vertical inlet positions of an open channel are investigated via a three-dimensional numerical model. Pollutants are injected from time-dependent sources in a turbulent free-surface flow. Numerical computations were carried out using Fluent 6.3, which is based on the finite volume approach. The air/water interface was modeled with the volume of fluid method (VOF). By focusing on investigating the influences of the flow on pollutants, it is found that with an increase of the injection rate, the pollutant concentration increases along the channel and the longitudinal dispersion is higher. On the other hand, it is noted that the point of injection modifies significantly the dispersion pattern of pollutant. These findings may be of great help in cost-effective scientific countermeasures to be taken into account for accident or planned pollutants discharged into a river.

Industrial activities and urbanization have had a major consequence for estuarine ecosystem health and water quality globally. Likewise, Sydney estuary has been significantly impacted by widespread, poor industrial practices in the past, and remediation of legacy contaminants have been undertaken in limited parts of this waterway. The objective of the present investigation was to determine the effectiveness of remediation of a former Pb-contaminated industrial site in Homebush Bay on Sydney estuary (Australia) through sampling of inter-tidal sediments and mangrove (Avicennia marina) tissue (fine nutritive roots, pneumatophores, and leaves). Results indicate that since remediation 6 years previously, Pb and other metals (Cu, Ni and Zn) in surficial sediment have increased to concentrations that approach pre-remediation levels and that they were considerably higher than pre-settlement levels (3–30 times), as well as at the reference site. Most metals were compartmentalized in fine nutritive roots with bio-concentration factors greater than unity, while tissues of pneumatophores and leaves contained low metal concentrations. Lead concentrations in fine nutritive root, pneumatophore, and leaf tissue of mangroves from the remediated site were similar to trees in un-remediated sites of the estuary and were substantially higher than plants at the reference site. The situation for Zn in fine nutritive root tissue was similar. The source of the metals was either surface/subsurface water from the catchment or more likely remobilized contaminated sediment from un-remediated parts of Homebush Bay. Results of this study demonstrate the problems facing management in attempting to reduce contamination in small parts of a large impacted area to concentrations below local base level.

This study, based on the N-shaped cubic model of the environmental Kuznets curve, analyzes the evolution of per capita greenhouse gas emissions (GHGpc) using not just economic growth but also public budgets dedicated to energy-oriented research development and demonstration (RD&D) and energy intensity. The empirical evidence, obtained from an econometric model of fixed effects for 28 OECD countries during 1994–2010, suggests that energy innovations help reduce GHGpc levels and mitigate the negative impact of energy intensity on environmental quality. When countries develop active energy RD&D policies, they can reduce both the rates of energy intensity and the level of GHGpc emissions. This paper incorporates a moderating variable to the econometric model that emphasizes the effect that GDP has on energy intensity. It also adds a variable that reflects the difference between countries that have made a greater economic effort in energy RD&D, which in turn corrects the GHG emissions resulting from the energy intensity of each country.