This paper investigates the electrochemical treatment of polychlorinated biphenyl (PCB) contaminated soils. The research was performed within a project co-funded by the European Regional Development Fund and for the experimental part; artificially contaminated soil with PCB was used. Two reactors of different sizes were used; the smaller designed in a Ph.D. research and the larger in a research project co-funded by the European Regional Development Fund. Specific voltage, current density, redox potential, time and pH values were considered throughout the tests. The initial PCB concentration in the test soil (3.571 mg/kgdw) exceeds the intervention threshold for sensitive use according to Romanian regulations (1 mg/kgdw). Three different tests were performed: within the first one (T1) the soil was polluted with insulating oil; within the other two tests (T2 and T3) the soil was contaminated with capacitor oil. The initial PCB concentrations within the three tests (as a sum of all PCB concentrations) were: 4.4461 mg/kgdw within T1, and 3.5710 mg/kgdw within both T2 and T3. The study showed that the electrochemical treatment could achieve up to 87 % remediation efficiency for PCB polluted soils. Therefore, this treatment is relevant and a potential solution for the remediation of PCB polluted soils.

The work reported here demonstrates that zero valent iron (ZVI), a material used in permeable reactive barriers, yields degradation rate constants for trichloroethylene (TCE) that are considerably different depending on whether they are determined in deionised water or in groundwater. Batch studies using ZVI and TCE-spiked deionised (DI) water and TCE-contaminated groundwater revealed that within 50 h, 80 % of the TCE present in groundwater was mineralised, compared to TCE-spiked deionised water in which only 50 % of TCE was demineralised by ZVI in 50 h. In both TCE-spiked groundwater and DI water, cis-dichloroethylene was the major by-product, and it was reduced together with TCE after 96 h of treatment. Along with changes in concentrations of TCE and its metabolites, increased levels of chloride confirmed TCE degradation. TCE-spiked groundwater gave a higher rate constant (k) under similar conditions. The elevated chloride (830 mg/l) concentrations of the groundwater could be a possible reason for this higher rate constant, in spite of the fact that groundwater also contains higher inorganic carbon (132 mg/l) and calcium (26 mg/l) and has a pH of 7.9. The rate constant (0.017-0.03223 h-1) and half-life of TCE (21.5 to 40 h) are within the reported ranges in the literature. The implications of the results for the performance of ZVI in permeable reactive barriers are that not only groundwater chemistry, but also groundwater flow conditions, plays a key role in TCE degradation. © 2013 Springer Science+Business Media Dordrecht.

The flux of metals at the tidal limits of major rivers are an important metric of freshwater contaminant transfer to marine habitats, reported in Northeast Atlantic bordering countries under the 1992 Oslo-Paris (OSPAR) Convention. This paper presents an assessment of long-term OSPAR data for four trace metals (Cd, Cu, Pb, and Zn) using a range of spatial datasets to assess the broad distribution of metal flux and yield across England and Wales. Mine site records and geological and land use data are used to classify river basins into six classes. The bulk of metal flux to seas around England and Wales occurs from catchments containing extensive mineralization and a legacy of metal mining (52 % of the total Zn flux, 47 % of Pb, 39 % of Cu, and 48 % of Cd were associated with mined catchments). Catchment area, metal flux from point mine discharges at source, and extent of mineralization typically accounted most for variation in catchment outlet metal flux in stepwise multiple linear regression (SMLR). There are a number of small mining-impacted rural catchments contributing significant fluxes of metals to coastal waters. Of particular prominence are Restronguet Creek (drainage area 87 km²) in southwest England that discharges 176 t Zn/year and 18 t Cu/year and the Afon Goch Dulas (27 km²) in north Wales, which releases 20 t Zn/year and 9 t Cu/year. Although such exercises cannot directly determine the provenance of metals, comparison with metal release data and a review of catchment-scale studies suggest a critical role of mining-related contaminants in contributing to catchment metal export.

The environmental impact assessment of mining sites represents nowadays a large interest topic in Romania. Historical pollution in the Rosia Montana mining area of Romania caused extensive damage to environmental media. This paper has two goals: to investigate the environmental pollution induced by mining activities in the Rosia Montana area and to quantify the environmental impacts and associated risks by means of an integrated approach. Thus, a new method was developed and applied for quantifying the impact of mining activities, taking account of the quality of environmental media in the mining area, and used as case study in the present paper. The associated risks are a function of the environmental impacts and the probability of their occurrence. The results show that the environmental impacts and quantified risks, based on quality indicators to characterize the environmental quality, are of a higher order, and thus measures for pollution remediation and control need to be considered in the investigated area. The conclusion drawn is that an integrated approach for the assessment of environmental impact and associated risks is a valuable and more objective method, and is an important tool that can be applied in the decision-making process for national authorities in the prioritization of emergency action.

In this work, a coal combustion ash (CCA) has been tested as an alternative low-cost sorbent to commercial activated carbons (GAC) for cadmium and zinc removal from polluted water. To this aim, the effect of pH and metal concentration on CCA adsorption capacity has been investigated, and a comparative analysis with GAC has been carried out in the same experimental conditions. Furthermore, in order to improve CCA adsorption capacity, two different activation treatments of raw CCA have been tested. In particular, the CCA was subjected to a gasification process conducted with steam and to different acidic treatments, conducted either with hydrochloric acid or nitric acid at different acid concentrations. Experimental results showed that all the acid treatments determined a substantial reduction of both cadmium and zinc adsorption capacity. Differently, the steam gasification determined a substantial increase in adsorption capacity with respect to raw CCA, in particular for zinc as its adsorption capacity resulted even higher than the correspondent of GAC. Finally, a thorough analysis of sorbent physical and chemical properties and of adsorption data allowed the individuation of the main cadmium/zinc adsorption mechanism both on CCA and activated carbon, adequately described by the Freundlich model.

The ubiquitous presence of chlorophenols (CPs) continues to be a cause of concern, owing to their recalcitrant nature. In this context, the present work investigated the degradation of model compounds, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol, by an organic oxidant, methyl ethyl ketone peroxide (MEKP) coupled with ultraviolet irradiation in basic media. Chemical analysis was followed by high-performance liquid chromatography and gas chromatography–mass spectrometry. Despite exhibiting varied patterns of decline, chemical oxygen demand was eventually noted to decrease to the extent of up to 70 %. Simultaneous increase/decrease in the release of chloride ions and decrease in pH indicated that parallel reactions were occurring, which led to the formation of acidic reaction products. First-order dynamics was approximated for all CP congener degradation. The degraded compounds showed absolutely no presence of chlorine atoms, which was a noteworthy feature testifying to the fact that MEKP action was capable of detoxification of CP congeners.

Geochemical characterization of two landfills, one closed and the other still active, both located near Komotini (Thrace, Greece), has been carried out. The aim was to provide an integrated and reliable methodology for a rapid assessment of the real impact of a municipal solid waste landfill, in the main environmental matrices (air and water) of the surrounding areas. The chemical (CO₂, CH₄, CO, H₂, N₂, and O₂ + Ar) and isotopic characterization (δ¹³C₍CO₂₎ and δ¹³C₍CH₄₎) of landfill gas and chemical (Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻, SO₄ ²⁻, HCO₃ ⁻, NH₄ ⁺, NO₃ ⁻, NO₂ ⁻, B, COD, Fe, Mn, As, Cr, Ni, Cu, Zn, Cd, Pb, and Hg) and isotopic analysis (δD, δ¹⁸O, tritium content, and δ¹³CDIC) of leachate, stream waters and groundwaters, and flux survey on the air–soil interface has been carried out. Combined chemical and isotopic analysis of the fluids collected inside and in the surroundings of the Komotini landfills supply a detailed picture of biogas emission and composition as well as of leachate chemistry and interaction with local waters. The results arising in this case study demonstrate that it is possible to propose a quick and reliable geochemical protocol to get a detailed picture of the state of health of the environment around a landfill.

Aquatic birds are often used as a health indicator of the marine ecosystem. African penguins living in the zoo make good research material as they form a link between the marine and the terrestrial ecosystem in terms of xenobiotic circulation. Tests were performed on whole herring—the food of the penguins—as well as on bird muscle, liver, brain, eggs, feathers and guano in order to determine total mercury, aldrin, dieldrin, endrin, isodrin, endosulfan isomers, endosulfan sulfate, methoxychlor, dichlorodiphenyltrichloroethane (DDT) and its metabolites. In herring and penguin, the tests did not show the presence of β-endosulfan, endosulfan sulfate, aldrin and isodrin. It was shown that penguins absorb about 36.8 μg of organochlorine pesticides and 4.6 μg of mercury with their food on a daily basis. Xenobiotics accumulate mostly in the liver, from where they are transported to the muscles and the brain, where the highest bioaccumulation factor is reached by endrin and pp’-DDT. Conceivably, the older the penguin, the higher is the concentration level of pesticides in its liver and brain. Molting was found to be the most effective way of eliminating mercury, dieldrin and methoxychlor from the system. Insecticides, such as DDT and its metabolites, were removed most effectively by females through laying of eggs. The standard four eggs laid within a year may have contained up to 20 % of the total amount of pesticides which had been absorbed with food, but no more than 5 % of mercury.

Rural non-point source (RNPS) water pollution control is problematic in Hubei Province, which is a typical agricultural region with abundant rainfall and a developed natural surface water network. The concept of best management practices (BMP) originating from the USA has already been introduced with the aim to reduce the application of chemical fertilizers and pesticides, and water and soil loss. However, a comprehensive evaluation of rural wastewater and nutrient reutilization to benefit the rural communities and the environment has not been attempted. To fill this gap, this review paper explores the major contributors of RNPS water pollution in Hubei Province, assesses the status of watercourses and discusses the prevalent ecological engineering techniques including vegetated filter strips (VFS), ecological ditches (ED), constructed wetlands (CW), and biogas plants (BP) with respect to aspects such as water purification, energy generation, and nutrient reduction and recirculation. Findings indicate that RNPS water pollution continuously increased for the past 10 years. Chemical fertilizers, poultry and livestock breeding, aquaculture, and rural living are the major sources of elevated chemical oxygen demand, ammonia–nitrogen, total nitrogen, and total phosphorus loads discharged to receiving watercourses. Finally, ecological engineering technologies such as VFS, ED, CW, and BP are proposed for villages and communities to combat RNPS water pollution. BMP are a promising approach to create a sustainable agricultural system, improve the rural energy consumption structure and living conditions, decrease wastewater discharges, and reduce chemical fertilizer application rate.

The removal and sorption of oil from saline solutions by leaves (L) and roots (R) of Pistia stratiotes are described for the first time. The effects of biomass dose (0.5 and 1.0 g), contact time (30, 60, 90, and 120 min), and initial oil concentration (IOC = 979 ± 9.82, 1,968 ± 8.01, 3,935 ± 40.09, 7,778 ± 196.42, and 15,694 ± 196.41 mg L⁻¹) on removal and sorption (q) were evaluated. Studies included a physicochemical characterization of the biomass. High oil removal (L = 93.71 ± 0.18 % and R = 80.93 ± 0.11 %) and sorption values (L = 2,904.47 ± 4.49 mg g⁻¹ and R = 2,324.38 ± 29.29 mg g⁻¹) were found. Such a high sorption might be related to factors such as a high surface area (128.38 ± 0.61 and 112.62 ± 5.17 m² g⁻¹, for leaves and roots, respectively), a high degree of relative hydrophobicity in the case of the leaves (71.05 ± 0.71 %), and capillary action. A high correlation was found between IOC and sorption, suggesting that the biomass could adsorb oil at IOCs higher than 15,694 ± 196.41 mg L⁻¹. The Freundlich isotherm model was found to best describe crude oil sorption by leaves and roots of P. stratiotes. These sorbent materials could be good candidates to be used during an oil spill.