Biochar has great potential as a soil amendment to immobilize heavy metals, thereby reducing their bioavailability. In this study, biochars derived from chicken manure and green waste were compared with commercial activated carbon (AC) and laboratory produced black carbon (BC) for the sorption of Pb and Cd. Sorption kinetics and equilibrium sorption isotherms for Pb and Cd were obtained for the char materials and the data were fitted to kinetic and sorption isotherm models. Chicken manure-derived biochar (CM) showed the highest sorption capacity for both Pb and Cd, and the Pb sorption by biochars was higher than the Cd sorption because of the precipitation of Pb with various ions released from the biochars such as carbonate, phosphate, and sulfate. The sorption data for both Pb and Cd were better represented by the pseudo-second order kinetic model than the pseudo-first order kinetic model, which indicates chemical sorption between biochar and metals. For the isotherm studies, char materials was mixed with various amount of Pb or Cd solutions and the remaining metal concentration was measured. The equilibrium sorption data followed a Langmuir isotherm with a maximum sorption capacity of 6.8-11 and 1.7-8.0 mg/g by biochars for Pb and Cd, respectively. Furthermore, CM immobilized Pb and Cd up to 93.5 and 88.4 %, respectively, while BC was not effective in the immobilization of Pb in soil. Overall, the sorption experiments in solution and the immobilization experiment in soil showed that biochars are more effective than AC in the sorption of Pb and Cd, and that they have the potential to be used as a soil amendment to remediate metal-contaminated soil. © 2013 Springer Science+Business Media Dordrecht.

Arsenic contamination of groundwater and surface water is widespread throughout the world. Considering its carcinogenicity and toxicity to human and animal health, remediation of arsenic-contaminated water has become a high priority. There are several physicochemical-based conventional technologies available for removing arsenic from water. However, these technologies possess a number of limitations such as high cost and generation of toxic by-products, etc. Therefore, research on new sustainable and cost-effective arsenic removal technologies for water has recently become an area of intense research activity. Bioremediation technology offers great potential for possible future application in decontamination of pollutants from the natural environment. It is not only environmentally friendly but cost-effective as well. This review focuses on the state-of-art knowledge of currently available arsenic remediation methods, their prospects, and recent advances with particular emphasis on bioremediation strategies.

Wetlands in mountain environments provide critical ecosystem services but are increasingly threatened by agricultural land use intensification. This study evaluates agricultural nonpoint source nutrient pollution transport in a wetland–stream–lake complex in a mountain, tussock grassland catchment in the South Island, New Zealand. Flow and water-quality monitoring in the Lake Clearwater catchment during three flow events from May to August 2010 (autumn high flow, winter low flow, and winter high flow) showed high concentrations and exceedances of water quality guidelines for total nitrogen (TN) and total phosphorus (TP) in small ephemeral streams draining agricultural land during high flows. Concentrations were attenuated through the wetlands to below guidelines, with the exception of TN which still remained slightly higher. Most TN was in the organic form above and below the wetland, suggesting N sources from animal waste/agricultural land and organic material and vegetation within the wetland. Most TP was particulate associated with suspended solids during high flows. Dissolved forms of N and P generally were below guidelines. Flows and loads (instantaneous and daily) increased at the lake outlet during winter high flow, indicating unaccounted sources to the lake from groundwater, the wetlands, or the lake sediments, and seasonal N saturation. Infiltration losses to shallow groundwater along the main perennial tributary likely re-appear as discharge to the wetlands and lake downstream. Surface–groundwater interactions play a dominant role in N transport to the wetland complex due to highly permeable soils and glacial alluvial deposits. Loads and unit loads of TN and TP were also elevated in the ephemeral streams. Results show that TN and TP concentrations and unit loads during high flows in ephemeral streams in this mountain grassland catchment are similar to, or higher than, values for impacted lowland pasture catchments. Although impacts to the wetland ecosystem have not been observed to date, the lake is shifting toward a mesotrophic state, and further research is needed to elucidate impacts of nutrient loads and help meet conservation and restoration goals.

Major incidents involving mine waste facilities and poor environmental management practices have left the legacy of thousands of contaminated sites like in the historic mining areas in the Carpathian Basin. Associated environmental risks have triggered the development of new EU environmental legislation to prevent and minimize the effects of such incidents. The Mine Waste Directive requires the risk-based inventory of all mine waste sites in Europe by May 2012. In order to address the mining environmental problems, a standard risk-based pre-selection protocol has been developed by the EU Commission. The protocol consists of 18 simple questions about contamination source, pathway and receptor. This paper evaluates the protocol by applying it to real-life cases, adopting it to local conditions, comparing to the similar method of the European Environmental Agency standard Preliminary Risk Assessment Model (PRAMS) and by carrying out uncertainty analysis. All together, 145 ore mine waste sites have been selected for scientific testing and evaluation using the EU Mining Waste Directive (MWD) Pre-selection Protocol as a case study from Hungary. The proportion of uncertain responses to questions in the protocol for the mine waste site gives an insight of specific and overall uncertainty in the data used. Questions of the EU MWD Pre-selection Protocol are linked to a GIS system, and key parameters such as the topographic slope and distance to the nearest surface and groundwater bodies to settlements and protected areas are calculated and statistically evaluated in order to adjust the RA models to local conditions in Hungary. Results show that the adjustment of threshold values to local conditions is necessary; however, the EU MWD Pre-selection Protocol is robust and is relatively insensitive to threshold values. Results of the EU MWD Pre-selection Protocol are consistent with the pre-screening European Environmental Agency PRAMS model which further confirms that the Protocol delivers reliable selection results that are not sensitive to the selected parameters. An interesting outcome of the study is that the highest uncertainty is associated with the engineering conditions of the waste facilities, such as the heights and size.

Electrokinetic extraction, which is an emerging technology, can be used for in situ removal of contaminants by the application of a direct current (DC) electric field across the contaminated subsurface soil. In this study, a kaolinite spiked with Pb (720 mg kg-1) was used to investigate the removal of Pb through electrokinetic extraction in the presence or absence of a cation selective membrane (CSM). The contaminated kaolinite was subjected to a constant DC voltage (2 V cm-1) for 4 days. A low DC voltage applied in absence of CSM developed a high pH interface within the electrokinetic cell. The mobility of Pb thus decreased due to the remarkable rise in the pH values. The inclusion of a CSM improved the removal efficiency but could not achieve the critical surface pH (<pH 3.5). The removal efficiency increased in the presence of Ca(NO3)2, such that 95 % of the spiked Pb was extracted from kaolinite, with 88 % of the Pb being recovered from the cathode chambers. In contrast, only 24 % of the spiked Pb was removed in the presence of ethylenediaminetetraacetic acid (EDTA). Moreover, Pb was detected in the anode chamber solution and 60 % of the spiked Pb accumulated at the anode. In the presence of both EDTA and Ca(NO3)2, Pb migrated and accumulated at the anode, thus indicating that Ca has a negligible effect in the presence of EDTA. © 2013 Springer Science+Business Media Dordrecht.

A first-to-date comprehensive climatological aspect of the regime of aerosol loading over the entire broader Greek region (19 E-30 E and 34 N-43 N) is obtained using pixel-level (50 km × 50 km) monthly aerosol optical depth (AOD) products derived from raw Level-2 (10 km × 10 km) MODIS-Terra AOD data at 550 nm. The AOD climatology (for the 8-year period from March 2000 to February 2008) indicates that the study region is significantly loaded by aerosols (mean regional AOD equal to 0.196 ± 0.030 on an annual basis, with values ranging from 0.126 up to 0.382 at pixel level). It is also found that our high-resolution AOD data can reveal spatial patterns that are not evident in studies based on lower resolution data. There is a distinct longitudinal gradient of AODs, with higher values in the eastern than western part of the Greek peninsula. There is also a strong latitudinal gradient with decreasing values from south to north attributed to the presence of the Sahara Desert in northern Africa. The annual AOD cycle presents double maximum values, in spring and summer, and minimum ones in winter. There is also a remarkable year-by-year variability of AOD levels, especially as to their maxima, influenced by varying transport of desert dust, from the south, or biomass burning aerosols, from the north, to the region under prevailing favorable synoptic conditions. In this work, the processing, consisting in averaging over space and time, is done applying/testing five different criteria varying in their flexibility/severity in both spatial and temporal data availability. The criteria selection affects the magnitude of computed regional mean AOD value modifying it by up to 19 %, although the patterns of geographical distribution of AOD and its intra-annual variability do not change drastically. © 2013 Springer Science+Business Media Dordrecht.

A chitosan-graft-poly(N-allyl maleamic acid) hydrogel membrane was prepared by radical polymerization in the absence of a cross-linker. The product was characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) to confirm the formation of hydrogels. Transparent hydrogels have been observed to exhibit as much as 223.4 % swelling capacity, following pseudo-second-order kinetic models. The synthesized hydrogel membrane was subsequently utilized for removal of copper ions from an aqueous solution in the presence of several different functional groups. The effects on adsorption efficiency of various parameters such as time, temperature, pH, initial concentration of copper (II) solution, and amount of hydrogel were also investigated. The maximum adsorption capacity and efficiency were found to be 50.75 mg g-1 and 99.91 %, respectively, by the 0.004 mg adsorbent after 12 h of immersion in copper solution. Finally, the result showed that hydrogel membrane is pH sensitive to copper (II) adsorption and has maximum adsorption efficiency near to the pH of ground water. © 2013 Springer Science+Business Media Dordrecht.

The concentration of a range of endocrine disruptors: 17-β-estradiol, estrone, 17-α-ethinylestradiol, bisphenol-A, pentachlorophenol, triclosan, and butylbenzylphthalate, was analyzed by gas chromatography/mass spectrometry in the Wetland zone of Xochimilco, a periurban area of Mexico City, during an annual cycle. Samples were taken based on their level of use and by selecting sampling points related with activities such as agriculture, livestock, and urban, as well as their potential presence in water at the Cerro de la Estrella Wastewater Treatment Plant (WWTP) which supplies the majority of water (>90 %) to the study area. The compounds analyzed are present in a wide range of products from cosmetics to home care, pharmaceuticals, and subproducts of the food industry. The importance of identifying these compounds lies in the fact that they can disrupt the endocrine system of vertebrates, in particular reproductive gland function, affecting the development of organisms and their offspring. Pentachlorophenol, triclosan, bisphenol-A, butylbenzylphthalate, estrone, and 17-β-estradiol were detected in concentrations in nanogram-per-liter levels; 17-α-ethinylestradiol was always below the detection limit. The compounds showed a trend toward greater concentrations in the rainy season, probably due to the runoff that carries these compounds into the system.

The Upper Little Tennessee River (ULTR) possesses one of the most diverse assemblages of aquatic biota in North America, including the endangered Appalachian elktoe mussel (Alasmidonta raveneliana). Populations of the Appalachian elktoe declined significantly following a 2004 flood generated by hurricanes Frances and Ivan. Although the cause(s) of decline have yet to be determined, population declines may reflect exposure to contaminated sediment within the river system. The objectives of this study were to provide a preliminary assessment of the potential impact of sediment-associated trace metals on aquatic biota, particularly the Appalachian elktoe mussel, and to determine the source(s) of trace metals to the axial channel. Total sediment-associated Cu, Cr, Ni, and Zn concentrations within the ULTR locally exceeded threshold and probable effect guidelines for aquatic biota. These data are consistent with previous analyses that found particulate and dissolved concentrations of Cu in river waters periodically exceeded aquatic impact guidelines. However, the data conflict with (1) metal speciation analyses that show that Cu, Cr, and Zn are largely associated with the residual, non-available sediment phase, and (2) trace metal concentrations that are higher in mussel shells from the Tuckasegee River, a control site with intact populations, than in the ULTR. Moreover, the analyses suggest that most of the metals are derived from sulfide minerals contained within the underlying bedrock and, in the case of Cu, from locally used pesticides. The importance of the underlying bedrock as a significant long-term trace metal source suggests that Appalachian elktoe mussels were exposed to high levels of Cu, Cr, Ni, and Zn both before and after the 2004 event. Thus, it appears unlikely that the decline of Appalachian elktoe populations is related primarily to trace metals.

Albendazole (ALB) belongs to a group of benzimidazoles - classified as antiparasitic pharmaceuticals. Its widespread application results in the presence of this pharmaceutical in natural environment (water and soil). In this paper a suitable pretreatment method was established including sampling, freeze-drying and extraction. Vicia faba was used as model organism. ALB accumulation by plant tissues was observed in hydroponic culture as well as in soil. The range of pharmaceutical concentrations was 1.7 × 10-5 mol/L (in hydroponic culture) and 1.7 × 10-5 to 1.7 × 10-4 mol/kg air dry soil (in soil). Observations were conducted for 14 days. After this time biological material was freeze-dried and after homogenization, dimethyl sulfoxide (DMSO) extraction was performed. The recovery of ALB for the roots was 93 % while for the shoots 86 %. After cleaning, the samples were subjected to further analysis by HPLC system. Phosphate buffer and acetonitrile (50:50) were used as a mobile phase. Drug retention time was 6.3 min. Results obtained in this experiment indicate higher drug accumulation in roots rather than in the hypocotyl part of the plant, cultivated both in soil and in hydroponic culture. © 2013 The Author(s).