A comprehensive chemical characterisation of the ionic and metallic composition of PM₂.₅fraction of suburban aerosol collected with high‐volume aerosol samplers at a coastal suburban site of northwest Atlantic European is studied over a 1.5-year period (from March 2011 to August 2012). The monthly mean PM₂.₅mass concentrations (after gravimetric measurement) ranged from 13 to 26 μg m⁻³. Eighteen samples, which provide information pertaining to the monthly variation in chemistry, were analyzed. Trace metals (Al, As, Ba, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V and Zn) were analysed in PM₂.₅fraction after acid extraction (total metallic concentration) and after sonication-assisted water extraction (aqueous soluble fraction). Major inorganic ions (Cl⁻, NO₃⁻, SO₄²⁻, Na⁺, K⁺, Ca²⁺, Mg²⁺, NH₄⁺and C₂O₄²⁻) were also analysed in the aqueous fraction of PM₂.₅. Trace metal extractability in water was in the range 50–67 % with exception of Al (∼2 %), Fe (∼4 %) and Cr (∼18 %). After univariate, cluster (CA) and principal component (PCA) analyses and air mass backward trajectory analysis, marine, crustal and anthropogenic (including road traffic) sources were found for the inorganic composition of PM₂.₅. Results also suggest a great influence of cleaner Atlantic air masses and ubiquitous sources for K⁺, Mg²⁺, Fe, Ni and V.

Inactivation of pathogens present in animal manure prior to land application has justified the use of advanced technologies. However, some alternatives are expensive or not effective due to the organic material and suspended solids present in the effluent (e.g., ozone, UV light). The use of hydrated lime (calcium hydroxide, Ca(OH)₂) is an attractive wastewater treatment option due to the ability of lime to kill pathogens and to extract phosphorus from manure at an alkaline pH. The present study aimed to evaluate the soluble phosphorus removal and pathogen inactivation (Escherichia coli, Salmonella enterica serovar typhymurium and Porcine circovirus type 2), in the liquid fraction and in the solid generated after Ca(OH)₂ addition in swine wastewater, exposed for 3 and 24 h at different pH conditions: 9.0, 9.5, and 10.0. The results showed the efficiency of pH elevation with Ca(OH)₂ in the removal of soluble P at pH 9.0 and the total inactivation of E. coli, Salmonella, and P. circovirus type 2 at pH 10.0. The liquid fraction (reuse water) could be safely used for cleaning the swine production facilities, and the solid fraction (precipitated P) could be used as a secondary product and fertilizer.

In this study, two carbon materials [chicken manure biochar (CMB) and black carbon (BC)] were investigated for their effects on the reduction of hexavalent chromium [Cr(VI)] in two spiked [600 mg Cr(VI) kg⁻¹] and one tannery waste contaminated [454 mg Cr(VI) kg⁻¹] soils. In spiked soils, both the rate and the maximum extent of reduction of Cr(VI) to trivalent Cr [Cr(III)] were higher in the sandy loam than clay soil, which is attributed to the difference in the extent of Cr(VI) adsorption between the soils. The highest rate of Cr(VI) reduction was observed in BC-amended sandy loam soil, where it reduced 452 mg kg⁻¹ of Cr(VI), followed by clay soil (427 mg kg⁻¹) and tannery soil (345 mg kg⁻¹). X-ray photoelectron microscopy confirmed the presence of both Cr(VI) and Cr(III) species in BC within 24 h of addition of Cr(VI), which proved its high reduction capacity. The resultant Cr(III) species either adsorbs or precipitates in BC and CMB. The addition of carbon materials to the tannery soil was also effective in decreasing the phytotoxicity of Cr(VI) in mustard (Brassica juncea L.) plants. Therefore, it is concluded that the addition of carbon materials enhanced the reduction of Cr(VI) and the subsequent immobilization of Cr(III) in soils.

This paper aims to demonstrate the benefits of using a natural coagulant to enhance gravitational sedimentation of pig slurry. The separation process would lead to a liquid fraction, more biodegradable and with lower nutrient content, and a solid fraction highly concentrated in organic matter. Experimental trials were conducted in order to achieve the following objectives: (i) compare the effect of gravitational sedimentation with coagulation–flocculation process, (ii) compare the efficiency of conventional coagulants (such as aluminium sulphate or ferric chloride) with chitosan biopolymer and (iii) test the optimum coagulation–flocculation operational conditions to slurry sample. Assessment criteria included removal efficiencies but also took into consideration the advantages/disadvantages regarding sludge management. Results showed that gravitational sedimentation process can be improved by addition of coagulants; turbidity and COD removal increased around 2 and 3 times, respectively.

In this study, electrocoagulation (EC) with hybrid Fe–Al electrodes was used to remove antimony from contaminated surface water. Response surface methodology was applied to investigate the interactive effects of the operating parameters on antimony removal and optimize these variables. Results showed that the relationship between operating parameters and the response was well described by a second-order polynomial equation. Under the optimal conditions of current density 2.58 mA/cm², pH 5.24, initial concentration 521.3 μg/L, and time 89.17 min, more than 99 % antimony were removed. Besides, the antimony adsorption behavior in EC process was also investigated. Adsorption kinetics and isotherms studies suggested that the adsorption process followed well the pseudo-second-order kinetic model and the Langmuir adsorption model, respectively. Adsorption thermodynamics study revealed that the reaction was spontaneous, endothermic, and thermodynamically favorable. These results further proved that the main mechanism involved in antimony removal in EC process could be chemisorption.

Cs is a common radionuclide present in nuclear wastes and released from nuclear power plant accidents. It is hard to be removed from water with traditional technology. The current study aimed at developing of efficient cost-effective adsorbent for removing Cs with modified MCM-41 with specific functional groups –SH. Mesoporous material MCM-41 was selected due to its large surface area and tunable pore structure. Functional –SH groups were grafted into the pores of MCM-41 to enhance its capability of selective adsorption of Cs from multi-element (Co, Sr) water solution. The adsorption results showed that the maximum adsorption capacity was 29.24 mg/g. Both Langmuir and Freundlich models described the adsorption processes of Cs, indicating co-existence of both monolayer and multilayer adsorption in the surface and inner pores of the materials. TEM, FTIR, and Raman spectroscopy analyses indicated that –SH groups were successfully bounded into the pores of MCM-41. The present study approved the surface functional modified MCM-41 which might be a good alternative candidate for cleaning up of radionuclide Cs from nuclear power plant accidents and relevant nuclear accident events.

Mercury (Hg) bioaccumulation and depuration potential was assessed in the glass eel Anguilla anguilla over a 30-day period, through a mesocosm experiment. During exposure period, glass eels exhibited a significant increase in Hg concentration compared with the control ones, revealing great accumulation capability. Distinct bioaccumulation kinetics were observed depending on the exposure concentrations: a saturation model and a linear accumulation model were achieved for low and high Hg levels, respectively. After 72 h of depuration, glass eels lost around 2 and 10 % of the Hg previously accumulated; however, until the end of the experiment, they never reached the original baseline condition. Most importantly, organisms exposed to high Hg concentrations still retained contaminant levels exceeding the European threshold regulating human food consumption. This may raise serious health concerns, due to the species’ rising interest in the international cuisine.

Sediment, suspended particulate matter (SPM), water and clam Scrobicularia plana samples were collected in a temperate coastal lagoon with anthropogenic impact. Arsenic levels in sediments, SPM and water presented a spatial concentration gradient. A significant linear regression between arsenic levels in S. plana and SPM suggests particulate matter as the main route of arsenic exposure. Trend analysis showed that total arsenic concentrations in S. plana generally increased with size class, reflecting lifespan bioaccumulation. Despite being efficient in reflecting environmental contamination levels, results suggest that arsenic accumulation by S. plana may not be a passive process, given the proportionally lower accumulation in high contamination areas. Annual bioaccumulation rates ranged from 5.6 to 1 mg kg⁻¹ year⁻¹, suggesting a possible toxicity risk for individuals of the most contaminated area. Despite the absence of regulatory guidelines, food safety assessment highlighted possible adverse effects of consuming S. plana in most contaminated areas.

Submerged harbor steel structures often employ cathodic protection using galvanic anodes to guard against corrosion. A laboratory experiment, with three different cathodic protection configurations by galvanic aluminum-based anodes, was performed to evaluate the potential metal transfer from the anodic alloy dissolution into the surrounding marine water. The anode dissolution rate is proportional to the imposed current demands and induced a significant Al, In, and Zn transfer in the dissolved and particulate fractions of the corrosion product layers covering the anode surface. These layers were poorly adherent, even under low hydrodynamic conditions. Consequently, at the anode vicinity, the suspended particle matter and dissolved fraction of surrounding marine waters showed strong enrichments in Al and Zn, respectively, the values of which could potentially affect the adjacent biota. After the anode activation period, however, the metal inputs from galvanic anode dissolution are rapidly diluted by seawater renewal. At regional scale, these metal fluxes should be negligible compared to river and wastewater fluxes. These results also showed that it is difficult to assess the impact of the anode dissolution on the concentrations of metals in the natural environment, especially for metals included in trace amounts in the anode alloy (i.e., Cu, Fe, In, Mn, and Si) in the aquatic compartment.

Copper bioavailability, specially to plants, is strongly dependent on its chemical form, as for most metals. Copper-contaminated soil can be treated in situ by the addition of minerals such as Na-bentonite, which mixed with surface soil, can transform this pollutant to non-bioavailable forms. In this work, shelter experiments were conducted to study the time evolution of Cu speciation, in pristine soil as well as in amended one. A selective sequential extraction method was employed to determine the metal speciation in the samples. The results show that the major metal fraction is the organic matter-bound one, whereas the exchangeable fraction is very low, even the first day after Cu addition. The time evolution shows a slow decrease of the organic-bound Cu and a corresponding increase of the most stable mineral fractions. With the addition of Na-bentonite to copper-contaminated soil, the most stable mineral fractions increase whereas the organic-bound one decreases, showing essentially similar time dependence of the several metal fractions. Sodium bentonite could be effectively used for remediation of soils polluted with Cu.