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 congener-specific degradation pattern of polychlorinated biphenyls (PCBs) in Aroclor 1254 was investigated using a novel bacterial strain, Stenotrophomonas sp. JSG1, and it was accelerated by the surfactant, β-cyclodextrin. In addition, 4-chorobenzoic acid (CBA) degradation was also confirmed by the estimation of CBA depletion rate, microbial growth, and release of free chloride ion in mineral medium. Metal ions such as Ni²⁺, Hg²⁺ Ba²⁺, Cu²⁺, and NaCl (>4 %) were found greatly influencing the PCB degradation. However, Ca²⁺, Mg²⁺, Fe²⁺, and Mn²⁺ have not shown any impact on biodegradation. The bphC gene, which encodes an extradiol aromatic ring cleavage dioxygenase was successfully amplified and cloned. Phylogeny-based pairwise alignment of nucleotide sequences suggested that the cloned gene belongs to the extradiol dioxygenase family, but it showed high diversity to the traditional bphC gene. Results of the present investigation revealed that the Stenotrophomonas sp. JSG1 is an effective novel bacterium, which can be used in the PCB remediation studies.

This study examined the potential for regrowth of Escherichia coli in laboratory-incubated microcosms spiked with ultraviolet (UV)-disinfected sewage effluent and extracts derived from turfgrass or leaf litter. A second part of the study examined the potential of nutrients for predicting E. coli in two urban streams with point source effluent. Microcosms containing effluent and vegetation extracts were incubated for 72 h, samples were withdrawn over six time periods for measurement of E. coli. Streams were sampled every 2 weeks and E. coli and nutrients measured. E. coli counts in the microcosms exceeded the Texas state secondary contact recreation standard for surface water quality within 12 h for the turfgrass and within 18 h for leaf litter extracts. Univariate analysis of variance found that the interaction between vegetation extract source and concentration was more important than source of vegetation or concentration of extract alone. In the two streams sampled downstream of a point source effluent discharge, between 82 and 92 % of the variance in annual E. coli during high stream flow and between 55 and 57 % of the variance in annual E. coli during low stream flow was described by stream water-dissolved organic carbon (DOC) and dissolved organic nitrogen (DON), NH₄-N, NO₃-N, or PO₄-P. Once effluent is discharged to surface water, particularly during high flow conditions, DOC and DON derived from the landscape and nitrogen and PO₄-P derived from the effluent will provide ideal conditions for E. coli regrowth in surface waters downstream of the point source discharge.

Enzymatic precipitation provides a novel cost-effective and eco-friendly method for remediation of heavy metals from different industrial effluents such as tannery, electroplating, dye industries, and many more. This study has paid attention to bacterial alkaline phosphatase (BAP) from Eschericia coli C90 which catalyzes para-nitrophenyl phosphate (pNPP) and produces inorganic phosphate (Pi) that helps in the precipitation of heavy metals as metalphosphates. The kinetic behavior of BAP with pNPP in Tris-HCl was studied for pH regimes 8, 8.5, 9, 9.5, 10, 10.5, and 11 in detail. The results showed that the maximum activity of the enzyme was at pH 8.5 with an incubation period of 300 min at 37 C. Based on the kinetic data, experiments were performed at pH 8.5 and pH 10 to precipitate Cr3+, Cr6+, Cd2+, Ni2+, and Co2+ from single-ion solutions (250 and 1,000 ppm concentrations) as well as industrial effluents, and the amount of metal precipitated as metalphosphate was derived by determining the amount of metal reduced in the supernatant of the reactions employing atomic absorption spectrophotometer. The precipitation of metals from single-ion solutions at pH 8.5 for 300 min incubation period followed the order Cd2+ > Ni2+ > Cr3+ > Cr6+ > Co2+. In the experiments involving effluents from tannery and electroplating industries, precipitation of 35.1 % of Cr6+, 77.80 % of Ni 2+, and 57.42 % of Cd2+ was achieved from initial concentrations of 621, 97, and 122 ppm, respectively. © 2013 Springer Science+Business Media Dordrecht.

This paper discusses the effects of breakwaters on the Rimini coastal environment over the last half century. Sediment cores of 50 cm thick were collected in various seasons from 2002 to 2005 and were subsampled at surface and subsurface levels at 20 inshore and offshore stations in order to take account of various freshwater and wastewater inputs. A 240-cm sediment core was collected in the most impacted area in order to reconstruct the evolution of the marine ecosystem since the time of the breakwaters’ construction. Sediment grain size, physico-chemical parameters, nutrients and inorganic and organic contaminants were determined. The breakwaters have stopped coastal erosion but have given rise to a worsening of environmental quality. No impacts were detected outside the breakwaters. The integrated approach, using biogeochemical markers to reconstruct spatial and historical environmental trends within the sheltered area, proved to be very useful in highlighting its capacity for recovery and providing indications for coastal management.

Bottom slag and sewage sludge discharged from municipal solid waste incineration and sewage treatment plants were co-sintered for use as a cost-effective adsorbent for phosphate removal from aqueous solutions. The Langmuir isotherm model (which gives a better description of phosphate sorption than the Freundlich model) was adopted to describe the action of the synthesized adsorbent and also for phosphate sorption by either zeolite or ironstone. The model showed that the maximum sorption capacity of the synthesized adsorbent (27,030 mg kg-1) was 38.2 greater than for zeolite and 70.6 times greater than for ironstone. Desorption of phosphate from the synthesized adsorbent at different initial concentrations was about 4.98 %, which was several times lower than for zeolite. The phosphate removal capacity of the synthesized adsorbent remained constant for solution pH values ranging from 3 to 10, which was an improvement on the capacity of the other two adsorbents; its buffering capacity was also superior. The immobilization of phosphate on the synthesized adsorbent might be attributed mainly to complexation with Fe, Al, and Ca ions. Heavy metal ion concentrations in the leachate of the synthesized adsorbent were negligible. © 2013 Springer Science+Business Media Dordrecht.

The catalytic effect of Cu(II) on the formation of disinfection by-products (DBPs) and chlorine degradation during chlorination of humic acid (HA) solutions was comparatively investigated under different experimental conditions. The experimental results showed that the total organic halogen (TOX) and trihalomethane (THM) formation increased with increasing Cu(II) concentration during chlorination, while haloacetic acids (HAAs) increased insignificantly. Accelerated chlorine decay and increased TOX and HAA formation were observed at high pH in the presence of 1.0 mg/L Cu(II) compared with that observed at low pH but THM formation decrease. Furthermore, the Cu(II) effect catalyzed the formation of brominated DBPs as it did for chlorine analogues in the presence of bromide ion. The microcalorimetry analysis demonstrated that more DBPs were formed in the Cu(II)-catalyzed chlorination, in which second-order rate constants obtained from reaction of HA with chlorine under given experimental conditions were 0.00256 M⁻¹ s⁻¹ (without Cu(II)) and 0.00865 M⁻¹ s⁻¹ (with Cu(II)), respectively. To discriminately examine the role of Cu(II) in greater detail, nine model compounds, which approximately represent the chemical structural units of HA, were individually oxidized by chlorine. It was demonstrated that carboxylic acids significantly enhanced the formation of TOX, THMs, and HAAs in the presence of Cu(II). Based on the previously published information and our experimental results, the possible pathway for Cu(II)-catalyzed TOX, THM, and HAA formation from chlorination of carboxylic acids were tentatively proposed.

A simple flow-based method was developed for the selective separation of arsenic species (+3 and +5) using a macrocycle-immobilized solid phase extraction (SPE) system, commonly known as molecular recognition technology (MRT) gel. Arsenic species in solution or in the eluent were subsequently quantified with graphite furnace atomic absorption spectrometry. The separation behaviors of As(III) and As(V) on MRT–SPE were investigated. It was found that As(V) can be selectively collected on the SPE system within the range of pH 4 to 9, while As(III) was passed through the MRT–SPE. The retention capacity of the MRT–SPE material for As(V) was found to be 0.25 ± 0.04 mmol g⁻¹. The detection limit of the method for As(V) was 0.06 μg L⁻¹, and the relative standard deviation was 2.9 % (n = 10, C = 1 μmol L⁻¹). Interference from the matrix ions was studied. In order to validate the developed method, certified reference materials of effluent wastewater and groundwater samples were analyzed, and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the speciation analysis of tri- and pentavalent arsenic in natural water samples showing satisfactory recoveries (≥ 98.7 %).