Cantabria is a small region located in Northern Spain that combines different land uses; thus, urban, industrial and rural areas are present in a relatively small area (5300 km2); however, the anthropogenic influence is evident by studying the deposition of metals towards these areas. Three sampling sites (industrial, urban and rural) were selected to assess the variability in metal deposition. Sampling was carried out monthly (from January 2012 to July 2012) using a bulk (funnelbottle) sampler. As, Cd, Cr, Cu, Mn, Mo, Ni, Pb, Ti, Zn and V were determined in the water-soluble and in the insoluble fractions of deposition samples. The impact of the human activities in the industrial area can be seen on several metals such as Pb, Zn, Cu and Mn. The most obvious influence was found for Mn, high fluxes were measured in the industrial site with a mean value of 2260 μg/m2·day; in contrast to urban (99.6 μg/m2·day) and rural (15.3 μg/m2·day) areas. The lowest flux values were found in the rural area for all the elements. Enrichment Factor (EF) analysis were also studied for the three sites. The high EFs values found for Pb, Mn, Cu, and Zn (>100) in the industrial site point to significant anthropogenic sources, mainly originated from industrial activities (steel and ferro-manganese alloy manufacturing plants) and road traffic.

To investigate the reaction of calcium hydroxide with CO2 and SO2 simultaneously, a gas containing both gases reacted with the calcium base at 58 ºC and a relative humidity of 55 %. Different CO2 and SO2 concentrations were performed being the composition of the gas stream 12, 6 or 0 % CO2; 5000, 2500, 1000 or 0 ppm SO2, 9.5 % synthetic air and balanced N2, with a flue gas rate of 1000 mL/minute. A continuous gas analyzer controlled the CO2 and SO2 concentrations in the effluent gas and the breakthrough curves of both gases were obtained. The gas analyzer data show that SO2 and CO2 compete to react with the base reacting simultaneously. By using thermogravimetry (TG), differential scanning calorimetry (DSC) and mass spectrometry (MS) techniques, calcium sulphite hemihydrate, CaSO3.1/2H2O, was identified as the unique desulfurization product detected. CaSO4 was not identified although O2 was present in the gas mixture. CaCO3 was the main product of the reaction of calcium hydroxide and CO2 being the complex CaO.CO2 another possible product synthesized in low amounts. From analyzer data it was proved that a part of the CaCO3 present in the sorbent or synthesized in the process reacts with the SO2 and release CO2. Results of this work show that the combination of continuous gas analyzer data and TG-DSC-MS techniques, not used before to study this reaction, is a good and easy way to clarify the process and the products of reaction. | Our acknowledgment to M.C. y T. for financial support of this work under Project MAT 2010-18862.

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.

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.

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.

The occurrence, as well as the environmental fate and impact, of vegetable oil spills in freshwater wetlands have until now been unreported. Thus, the largest global vegetable oil spillage in a freshwater wetland, which occurred at the Con Joubert Bird Sanctuary wetland in 2007, presented an ideal opportunity to evaluate these impacts. Five post-spill sampling sites were selected within the wetland from which a variety of abiotic and biotic samples were collected bi-monthly over a period of 12 months. Abiotic variables included the sediment and water column oil concentrations, total nitrogen, total phosphorous, biochemical oxygen demand (BOD), silica, chlorophyll a, as well as in situ measurements of pH, electrical conductivity, and dissolved oxygen. Aquatic macroinvertebrates were chosen as biotic indicators in the study field due to their wide applicability as water quality indicators and were thus collected at each site. Spatial and temporal changes in total nitrogen, total phosphorous, and chlorophyll a concentrations as well as changes in pH were observed. The oil spillage also resulted in an increase in tolerant macroinvertebrate taxa, mainly Chironomidae and Psychodidae, at the sites closest to the source of the spillage. These two taxa, and to a lesser extent, Syrphidae, were identified as potentially useful indicators to determine the extent of vegetable oil contamination within a freshwater wetland. Furthermore, monitoring of these indicator taxa can be a useful management tool to determine the recovery of freshwater wetlands after vegetable oil spills. In the study, a static battery of bioassays of different biotic trophic levels was also employed to determine the adverse effects of the spilled vegetable oil on the biotic environment. It was evident from the result of the static battery of bioassay that adverse effects of the sunflower oil differ between trophic levels. The latter was in relationship with the data obtained from the field macroinvertebrate study, indicating that certain macroinvertebrate families were more tolerant to the adverse effects of sunflower oil than other families. © 2013 Springer Science+Business Media Dordrecht.

Arrival of tar balls to the Goa coast during pre- and southwest monsoon seasons has been a regular phenomenon in the past few years. In one such event, we observed tar ball deposits along the Goa coast during August 2010, April 2011 and May 2011 when no oil spill was reported in the Arabian Sea (AS). The only source for the formation of tar balls could be the spill/tanker-wash from the tankers passing through the international tanker routes across the AS. Assuming this, an attempt has been made to simulate surface winds, currents and tar ball trajectories for August 2010 using hydrodynamics and particle tracking models. Tar ball particles were released numerically at eight locations in the AS, and five of them reached the Goa coast, matching reasonably well with the observations. The present study confirms our view that the source of these tar balls is the accidental spills or tanker-wash along the international oil tanker route in the AS. A review of the global scenario of tar ball study is also presented in the Introduction.

Imperata cylindrica leaf was used as raw material to prepare two different adsorbents through chemical modification by using sulfuric acid and phosphoric acid. These two adsorbents, sulfuric acid-modified I. cylindrica leaf-based adsorbent (SIC) and phosphoric acid-modified I. cylindrica leaf-based adsorbent (PIC), were used to adsorb nickel ions (Ni²⁺) from aqueous solutions. The I. cylindrica leaf-based adsorbent and modified I. cylindrica leaf-based adsorbents were characterized by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). Different operational parameters such as initial solution pH, adsorbent size, adsorbent dosage, initial Ni²⁺ ion concentration, and temperature were studied. The adsorption isotherm and the adsorption kinetics were studied systematically. Based on the FT-IR spectrum before and after adsorption of Ni²⁺ ions, the adsorption mechanism involved both ion exchange and complexation between Ni²⁺ ions and functional groups on the surface of adsorbents. There was no sulfur and phosphorus detected in the aqueous solutions after adsorption. Therefore, SIC and PIC are effective in adsorbing Ni²⁺ ions and will not cause secondary pollution to the environment.

The compositional changes of saturates, aromatics, resins and asphaltenes (SARA) fractions in aqueous clay/oil microcosm experiments with a hydrocarbon-degrading microorganism community were analysed using Iatroscan. The clay mineral samples used in this study were organomontmorillonite, acid-activated montmorillonite and K, Ca, Zn and Cr montmorillonites produced by modifying the original montmorillonite sample. The evaluation and quantification of biodegradation and adsorption were carried out using a combination of the Iatroscan and gravimetric analysis. The SARA compositions in the presence of organomontmorillonite and acid-activated montmorillonite after incubation follow the same pattern in which the aromatic fraction is higher than the other fractions unlike in the presence of unmodified, K, Ca and Zn montmorillonites, where the saturates fraction is higher than the other fractions. Changes in SARA fractions due to biodegradation seemed to occur most in the presence of unmodified and calcium montmorillonites; hence, the removal of SARA fractions due to biodegradation was significant and enhanced in the presence of these two clay samples. However, biodegradation in the presence of organomontmorillonite and acid-activated and Cr montmorillonites was hindered. The study indicated that Cr montmorillonite adsorbed resins most, whereas Zn and K montmorillonites adsorbed aromatics most after incubation.

Anionic polyacrylamide (PAM) is a linear, water-soluble anionic polymer that is widely used for erosion control and water quality protection. There has been an issue whether this formulation could possibly have negative effects on soil microbial diversity by altering microbial binding to soil particles or to one another and thus restricting their mobility and role in carbon and nutrient cycling. We conducted an 8-year study annually applying ultra-high rates of PAM to soil and then monitored impacts on soil bacterial diversity. In July and August, we measured active soil bacterial and fungal biomass and microbial diversity in soils receiving 0 (control), 2,691, and 5,382 kg active ingredient PAM ha⁻¹. Active microbial biomass in soil was 19–33 % greater in the untreated control than soil treated with 2,691 or 5,382 kg of active ingredient PAM ha⁻¹. Active bacterial biomass in soil was 21–31 % greater in the control treatment than in soil treated with 2,691 or 5,382 kg of active ingredient PAM ha⁻¹ in August, but not July. Active fungal biomass in soils was 38–50 % greater in the control treatment than soil treated with 2,691 or 5,382 kg of active ingredient PAM ha⁻¹ in July, but not August. Molecular methods were used to access the bacterial diversity, richness, and evenness in an agricultural soil that received 0 (control), 2,691, and 5,382 kg of active ingredient PAM ha⁻¹. We found that although soil receiving these massive PAM application rates and prolonged exposure may reduce active bacterial and fungal biomass, PAM application did not substantially or consistently affect bacterial structural diversity, richness, or evenness in this agricultural soil.