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.

The competitive adsorption of organic pollutants—phenol, aniline and n-heptane—from biologically treated coking wastewater on powdered activated carbon (PAC) was studied. Firstly, batch adsorption experiments of coking wastewater were conducted to investigate the effect of pH and temperature on their adsorption. Results showed that long-chain alkanes, benzoic, halogenated and phenolic compounds were adsorbed well under acidic condition, while amines were adsorbed well under alkaline condition; maximum co-adsorption amount of all kinds of organic compounds occurred at around pH 5. Then, Lagergren kinetic model and pseudo-second-order kinetic model were used to describe the adsorption process of phenol and aniline on PAC. The data were fitted very well with pseudo-second-order kinetics, and the adsorption capacity decreased with an increase in temperature, belonging to Freundlich multi-layer physical adsorption. The adsorption speed and capacity of phenol were superior to aniline in unitary and binary solution. The adsorption amount of n-heptane decreased by 26.6 % from ternary competitive absorption system of phenol, aniline and n-heptane compared with that in unitary solutions, which showed that phenol and aniline caused spatial adsorption steric hindrance to n-heptane.

Spring/summer surface ozone concentrations, [O3], in coastal environments were investigated: (1) by comparison of coastal and inland monitoring stations with data from a small island >5 km off the coast of southwest Sweden, (2) as a gradient from the coast towards inland in southernmost Sweden. Further, results from the chemical transport model MATCH were used to assess the marine influence on [O3]. It was hypothesised that [O3] is higher on the small island compared to the coast, especially during night and in offshore wind. Another hypothesis was that [O3] declines from the coast towards inland. Our hypotheses were based on observations that the deposition velocity of O3 to sea surfaces is lower than to terrestrial surfaces, and that vertical air mixing is stronger in the marine environment, especially during night. The island experienced 10 % higher [O3] compared to the coast. This difference was larger with offshore (15 %) than onshore wind (9 %). The concentration difference between island and coast was larger during night, but prevailed during day and could not be explained by differences in [NO2] between the sites. The difference in [O3] between the island and the inland site was 20 %. Higher [O3] over the sea, especially during night, was reproduced by MATCH. In the gradient study, [O3] declined from the coast towards inland. Both [O3] and [NO2] were elevated at the coast, indicating that the gradient in [O3] from the coast was not caused by NO titration. The conclusions were that surface [O3] in marine environments is higher than in coastal, and higher in coastal than inland areas, especially during night. © 2013 Springer Science+Business Media Dordrecht.

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.

Cadmium (Cd) is a non-essential heavy metal, considered a high-priority pollutant. It occurs naturally in the environment but anthropogenic activities may enhance its presence, with consequences to the biota. Metal research has been focused in the crustaceans but knowledge on estuarine isopods has been lacking. The aim of this study was to assess the bioconcentration kinetics in the estuarine key species Cyathura carinata. This isopod was exposed to different treatments of Cd, through aqueous pathway: control, low (I), medium (II) and very high (III) concentrations during 14 days, being collected along seven sampling times. After the end of the exposure period, the mean uptake rates were 0.023, 0.040 and 0.634 μg g⁻¹ day⁻¹ for each treatment, respectively. Statistical differences in accumulated Cd were recorded between treatments, except between control and treatment I. A linear pattern of accumulation through time was detected for all the concentrations, being most perceptible in the treatment III, where measured Cd in C. carinata’s tissues was significantly different between all the sampling times. Cd accumulation in treatments I and II was not so pronounced, being only noticeable at the end of the exposure period. In these treatments, final concentrations were two and almost four times greater than control, respectively, while in treatment III Cd concentration increased 60 times. Survival did not seem to be affected in the various treatments, suggesting the existence of a strategy for preventing toxic activity of Cd that needs further investigation.

Pot and field experiments were conducted to elucidate the phytostabilization potential of two grass species (Thysanolaena maxima and Vetiveria zizanioides) with respect to lead (Pb) tailing soil. Three fertilizers (Osmocote® fertilizer, cow manure, and organic fertilizer) were used to improve the physicochemical properties of tailing soil. V. zizanioides treated with organic fertilizer and cow manure showed the highest biomass (14.0±2.6 and 10.5±2.6 g per plant, respectively) and the highest Pb uptake in the organic fertilizer treatment (T. maxima, 413.3 μg per plant; V. zizanioides, 519.5 μg per plant) in the pot study, whereas in field trials, T. maxima attained the best performances of dry biomass production (217.0 ±57.9 g per plant) and Pb uptake (32.1mg per plant) in the Osmocote® treatment. In addition, both grasses showed low translocation factor (<1) values and bioconcentration coefficients for root (>1). During a 1-year field trial, T. maxima also produced the longest shoot (103.9±29.7 cm), followed by V. zizanioides (70.6±16.8 cm), in Osmocote® treatment. Both grass species showed potential as excluder plants suitable for phytostabilization applications in Pbcontaminated areas. © Springer Science+Business Media Dordrecht 2013.

Adsorption potentials of native and amine-modified plant biomass of Alyssum caricum for the removal of Reactive Green 19 (RG-19) and Reactive Red 2 (RR-2) dyes from aqueous solutions were studied. The adsorbents were characterized before and after modification process using Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and potentiometric titration analysis. Modification of the surface of A. caricum biomass with hexamethylenediamine (HMDA) showed an increase of 1.18-fold in its surface area. Batch studies illustrated that dye adsorption were highly dependent on different process variables, pH, initial dye concentration of solution, adsorbent dosage, and temperature. The maximum adsorption capacities of the native and amine-modified adsorbents were 27.6 and 63.4 mg/g adsorbent for RG-19 dye and 16.5 and 36.8 mg/g adsorbent for RR-2 dye, respectively. The adsorption of both dyes on the native and amine-modified plant biomass correlated well with the Langmuir and Temkin isotherm equations as compared to Freundlich and D-R equations. The calculated thermodynamic parameters for both native and amine-modified adsorbents showed that the adsorption was feasible, spontaneous, and exothermic. The information gained from these studies was expected to indicate whether native and amine-modified adsorbents can have potential to be used for the removal of other dyes from wastewaters. © 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.

Adsorption by low-cost adsorbents and biosorbents is recognized as an effective and economic method for low-concentration heavy metal. The purpose of this study was to investigate the possibility of the utilization of N,N′-bis(2, 5-dihydroxybenzylidene)-1, 4-diaminobenzene (DHDB)-immobilized sporopollenin (Schiff base-immobilized sporopollenin, Sp-DHDB) as a sorbent for removal of lead (II) ion from aqueous solution. The effects of different parameters (such as sorbate concentration, sorbent dosage, and pH of the medium) were investigated by differential pulse anodic stripping voltammetry (DPASV) technique. The experimental data were analyzed by the Freundlich, Langmuir, and Dubinin–Radushkevich (D–R) isotherms. Equilibrium data fitted well with the Freundlich model and the procedure developed was successfully applied for the removal of lead ions in aqueous solutions. This investigation reveals a new, simple, environmentally friendly, and cost-effective method for the removal of lead ions from aqueous solutions by a new Sp-DHDB material.

Decolorization of brilliant green (0.06 g/L), Evans blue (0.15 g/L), and their mixture (total concentration 0.08 g/L, proportion 1:1 w/w) by fungi was studied. Fungal strains [Pleurotus ostreatus (BWPH), Gloeophyllum odoratum (DCa), and Fusarium oxysporum (G1)] were used separately and as a mixture of them. Zootoxicity (Daphnia magna) and phytotoxicity (Lemna minor) changes were estimated after the end of experiment. Mixtures of fungal strains were less effective in decolorization process than the same strains used separately (as a single strains). After 96 h of experiment, living biomass of strain BWPH removed up to 95.5 %; DCa, up to 84.6 %; G1, up to 79.2 % where mixtures BWPH + DCa removed up to 74.3 %; and BWPH + G1, only up to 32.2 % of used dyes. High effectiveness of dyes removal not always corresponded with decrease of toxicity. The highest decrease of zootoxicity and phytotoxicity (from V to III toxicity class or to even nontoxic) was noticed for single strains, while no changes or slight toxicity decrease was noticed in samples with strains mixtures.