It was found that some of the medicinal plants accumulate increased amounts of toxic elements like Cd or Pb. Less is known about the accumulation of other hazardous elements like arsenic (As) and antimony (Sb) in these species. The present paper investigated selected medicinal plants naturally growing on old mining sites in Slovakia, Central Europe, contaminated by As and Sb. Both these elements are nonessential for plants and, in higher level, might be phytotoxic. The soil concentration of As and Sb at three different localities extensively used for mining of Sb ores in former times highly exceed values characteristic for noncontaminated substrates and ranged between 146 and 540 mg kg⁻¹ for As and 525 and 4,463 mg kg⁻¹ for Sb. Extraction experiments of soils show differences between As and Sb leaching, as the highest amount of mobile As was released in acetic acid while Sb was predominantly released in distilled water. In total, seven different plant species were investigated (Fragaria vesca, Taraxacum officinale, Tussilago farfara, Plantago major, Veronica officinalis, Plantago media, and Primula elatior), and the concentration of investigated elements in shoot ranged between 1 and 519 mg kg⁻¹ for As and 10 and 920 mg kg⁻¹ for Sb. Differences in the bioaccumulation of As and Sb as well as in the translocation of these elements from root to shoot within the same species growing on different localities have been found. This indicate that efficiency of As and Sb uptake might vary between individual plants of the same species on different sites. Increased bioaccumulation of As and Sb in biomass of investigated plants might be dangerous for human when used for traditional medicinal purposes.

Although degradation data for herbicides are essential in understanding their potential to be contaminants and are indispensable inputs in computer-based modeling of their fate in environment, most available data only concern surface soils. Soil samples, collected at two depths from four representative sites of a 31.4-ha field located in Blue Earth County, MN, USA, were used to determine acetochlor dissipation under laboratory conditions. A field study was also carried out within a 16-ha watershed in Dakota County, MN, USA, where 38 locations were sampled to obtain sample representative of the full range of soil properties found within the watershed. Acetochlor DT50 values ranged from 6.51 to 13.9 days for surface soils and from 20.3 to 26.7 days for subsurface soils. DT90 values were a factor of four times longer than for DT50 values. Field DT50 values for acetochlor dissipation were not significantly different for the 2 years, 5.7 ±2.5 and 7.7±4.5 days. Dissipation was slightly faster in the field as compared to the laboratory; however, the difference seems insignificant in view of the wide range in soil properties inMinnesota. In both studies, acetochlor would be classified as slightly persistent. For acetochlor, laboratory dissipation studies can be considered representative of field dissipation for the soils and climatic conditions in this study. Inclusion of subsoil degradation data in mathematical models used for ground water risk assessment may improve their capability of predicting potential movement of acetochlor to groundwater. © Springer Science+Business Media Dordrecht 2013.

There are significant concerns about the impact of heavy metal contamination in soils as a consequence of urbanisation and industrialisation in developing countries. Routine chemical analysis of soils is used to measure the total concentration of metals from point source or diffuse activities, but this fails to put in context the bioavailability of the analyte or the potential toxicity of multiple contaminants. Bacterial biosensors provide a useful tool for assessing the toxicity of the bioavailable fraction of heavy metals in soils and for complementing chemical analysis. There are few examples of genuine environmental applications of biosensors for pollutant diagnosis. This study applied constitutively marked biosensors (which were comprehensively characterised) to soils collected from across Northern China (60,000 km²). The biosensors were responsive to soils impacted by As, Cd, Cr, Cu, Hg, Pb, and Zn when compared to ‘uncontaminated controls’. The response of the biosensor correlated with individual (or groups of) metals related to their concentration and source. The geo-accumulation index (I gₑₒ) assisted in explaining the biosensor response. The constitutively marked biosensors offered a focussed understanding of analyte bioavailability and placed in a relevant context the elemental analysis. When matrix-matched control samples can be collected, then such a biosensor procedure (as adopted here) is applicable to contrasting soils exposed to a wide range of contaminants. Biosensor applications complemented routine soil chemical analysis for this regional-scale study.

Groundwater contamination caused by petroleum hydrocarbon (PHC) spills mostly from oil industry is a major environmental concern worldwide. However, infiltration into groundwater is decreasing due to the natural attenuation processes of PHCs in vadose zone, which acts as a safeguard of invaluable groundwater resource against contamination. This study was conducted to determine the retardation capacity of vadose zone and its influence factors based on investigations of a petroleum-contaminated site in NE China. Column leaching experiments in homogeneous and heterogeneous soils were utilized to simulate the actual infiltration process, which aimed to understand the variation of PHC compounds in vadose zone and to examine the effects of soil and water properties on the diversification of the compounds by using gas chromatography–mass spectrometry (GC–MS). The results showed that adsorption and biodegradation are dominant processes and 84 %, 76 %, and 66 % of the organic contaminants were entrapped in fine, medium, and coarse sands, respectively. This was mainly caused by the adsorption coefficient (K d ), which was linked with the soil properties; more specifically, smaller soil aggregates mean a higher K d value and such discrimination also exists among petroleum compounds. Real-time polymerase chain reaction (RT-PCR) and culture-based methods were applied to identify the degrading microorganisms. Results demonstrate that these microorganisms could degrade compounds such as chainalkanes (ChA), cycloalkanes (CyA), and aromatic (Ars) into asphaltenes (Asp). The microorganism population increased with biodegradation products and the consequence of biodegrading capacity was (from high to low): ChA, CyA, and Ars; chemical analyses in the heterogeneous soil experiment indicated that concentration of the biodegradation products in leachate was negatively correlated to dissolved oxygen (DO) as a consumption of oxidants but positively correlated to electrical conductivity (EC) and pH of water. Enzyme activities and microorganism population of soil were positively correlated to concentration of biodegradation products.

Mismanagement of soil and water resources may not only contribute to an escalation of global poverty but also jeopardize ecosystem services, with significant costs to the environment. Although not concentrated within one geographic location (3,500 million hectares), an equivalent of approximately 24 % of the earth's land surface is degraded land, and about 2 billion people (one third of the global population) lack access to safe and affordable water for domestic purposes. It is therefore critical to develop strategies targeted at the root causes of these problems. However, to do so would require a rapid and reliable information system that has been elusive because of the complexity of the environment and the limitations of the existing tools. The increased availability and development of remote sensing and geographic data analysis tools have opened up new possibilities for exploring and monitoring environmental variables influencing key land use and soil management options. Here, we explore the major concepts, describe the constraints, and the future potential of remote sensing for mapping and providing near real-time information on soil and water quality in the context of major land use practices employed at the global scale. © 2013 Springer Science+Business Media Dordrecht.

Surfactant-enhanced solubilization and subsequent biodegradation of phenanthrene and pyrene from aqueous solutions by Arthrobacter strain Sphe3 was investigated. The results show that growth of Arthrobacter strain Sphe3 was increased upon increase in concentration of Tween 20 and Tween 80. Inhibition of bacterial growth was observed with increasing Triton X-100 concentrations, whereas sodium dodecyl sulfate (SDS) totally inhibited this bacterial growth. Phenanthrene and pyrene solubilization was enhanced in the presence of surfactants and found to be linearly proportional to their concentrations, above the critical micelle concentration (CMC). In addition, Tween 20 and Tween 80 enhanced the biodegradation of phenanthrene and pyrene. The high correlation coefficient (R ²) values obtained at all the concentrations studied, suggest that biodegradation kinetics of both phenanthrene and pyrene in the presence of Tween 20 and Tween 80 follow first-order kinetic equation model. Experimental results suggest that Tween 20 and Tween 80 may have great potential for applications in bioremediation of these polycyclic aromatic hydrocarbon (PAH) compounds using Arthrobacter strain Sphe3.

Nanoscaled Bi₂O₃ particles coated on ZnO nanorods (ZNRs) have been fabricated by combining hydrothermal technique with a chemical precipitation method. X-ray diffraction, field emission-scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and UV–vis absorption and photoluminescence studies were adapted to characterize the structure, morphologies, and optical properties of the nanocomposites. The results indicated that small Bi₂O₃ nanoparticles were well distributed on the surfaces of ZNRs. And the Bi₂O₃–ZNR nanocomposites showed high charge separation efficiency and •OH generation ability as evidenced by photoluminescence spectra. Under irradiation of a 55-W compact fluorescent lamp, the Bi₂O₃–ZNR nanocomposites demonstrated photocatalytic activities higher than pure ZNRs in the degradation of two endocrine-disrupting chemicals, phenol and methylparaben, which might be attributed to the high separation efficiency of photogenerated electron–hole pairs based on the cooperative role of Bi₂O₃ loading on ZNRs. Moreover, the Bi₂O₃–ZNR nanocomposite could be easily recovered and reused due to their one-dimensional nanostructural property. All these characteristics brought enormous benefits of Bi₂O₃–ZNR nanocomposites to the practical application in indoor environmental remediation.

Boric acid-treated and sulfur ion-doped multi-modified TiO₂ films with high photocatalytic activities were prepared on soda–lime glass (Na₂O · CaO · 6SiO₂) substrates via the sol–gel method. The as-prepared specimens were characterized using high-resolution field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence spectra, UV–vis diffuse reflectance spectroscopy, and Brunauer–Emmett–Teller surface area. The photocatalytic activities of the films were evaluated by degradation of organic dyes in aqueous solutions. Compared with boric acid treatment and sulfur surface doping, the integration of both methods gave the best results. It is believed that high photocatalytic activity is correlated with the microstructure of the TiO₂ film.

Petroleum hydrocarbons in the bilge water of small fishing vessels are continuously released into the environment. The bilge water samples usually contained low amounts of oil-degrading bacteria; therefore, this study examines application of polyurethane foam (PUF)-immobilized Gordonia sp. JC11, a known lubricant-degrading bacterial inoculum, for the treatment of bilge water. Batch microcosm experiments showed that the PUF-immobilized bacteria were more efficient at removing oil than indigenous microorganisms and were able to remove approximately 40-50 % of the boat lubricant (1,000 mg L-1). The immobilized PUF samples rapidly adsorbed oil from the bilge water inside a small fishing vessel; however, the uninoculated PUF contained more oil than the inoculated PUF at most time points. The hydrocarbon components were also different when comparing inoculated and uninoculated PUF. These results indicate that the oil accumulated inside the PUF containing immobilized bacteria was being degraded by the Gordonia sp. JC11. However, these bacteria gradually die off after repeated oil exposure, and it is suggested that PUF-immobilized cells be replaced at timed intervals. This technique is considered simple and cheap; thus, it could be used to reduce chronic oil pollution from the release of bilge water. © 2013 Springer Science+Business Media Dordrecht.

Arsenic (As) adsorption onto metal oxide-precipitated clinoptilolite was investigated by using response surface methodology (RSM). Box-Behnken experimental design combined with RSM was used to examine and to optimize major process parameters. The quadratic statistical model was defined by three independent variables namely, pH (3-7), temperature (25-65 C), and initial arsenate (As(V)) concentration (0.5-9.5 mg L-1) while adsorption capacities of modified zeolites were designated as dependent variables. The iron oxide-precipitated zeolite (ZNa-Fe) was found to be more effective adsorbent when compared with aluminum oxide-modified one (ZNa-Al). The maximum As(V) adsorption capacities for ZNa-Fe and ZNa-Al were observed at pH 3.0 and pH 4.96, respectively. In the chosen range, higher adsorption capacities were achieved with increasing temperature, indicating the endothermic behavior of process for both samples. Initial As(V) concentration had a marked favorable effect on the amount of As(V) adsorbed onto adsorbents in the selected field. The constructed polynomial model was found significant, as was evident from the model F values (FZNa-Fe = 414.95 and F ZNa-Al = 167.17). The coefficients of determination values of second-order polynomial regression models were found as 0.9981 and 0.9953 for ZNa-Fe and ZNa-Al, respectively, indicating the accuracy and general availability of the model. © 2013 Springer Science+Business Media Dordrecht.