The chlor-alkali industry sector produces chlorine, sodium/potassium hydroxide and hydrogen by the electrolysis of brine. Nowadays, three different electrolysis techniques are applied: mercury, diaphragm, and membrane cell technology. From all these technologies, the European Commission labels the membrane process as the Best Available Technique (BAT) for the chlor-alkali industry. The membrane cell technology has fewer exhausts to the environment and it is relatively more efficient in the use of electric power that mercury and diaphragm. Nevertheless, despite the fact that the overall energy intensity has been reduced, the issue of energy consumption is still a major matter. A promising approach for reducing the electricity demand of chlor-alkali electrolysis is using oxygen-depolarised cathodes (ODC). ODCs are long known and have been successfully used in chlorine production through electrolysis of hydrogen chloride (HCl). The achieved environmental benefit of this technique is a reduction of energy consumption. However, the overall reduction of energy consumption is lower, as some energy is required to produce pure oxygen and because hydrogen is not co-produced, which could otherwise be used in chemical reactions or to produce steam and electricity via combustion or fuel cells. In this sense, the reduced electricity demand does not necessarily imply cleaner chlorine production. For that reason, this work proposes the use of the life cycle assessment (LCA) methodology to determine the environmental performance of the existing electrolysis technologies and to compare it with the ODC technique.

The evaluation of the spatial representativeness of air quality monitoring stations is of fundamental relevance when observed concentration levels are used in air quality assessment. Since no reference method is provided, there is a need to develop tools for its quantitative assessment. In this paper we test a recently developed methodology for spatial representativeness area assessment, based on the analysis of time series of model concentrations by means of a Concentration Similarity Frequency (CSF) function, on the Taranto-via Machiavelli industrial monitoring station, located in a mid-size city in Southern Italy. The complex territorial context, the peculiar anthropogenic emissions features, dominated by the contribution of the largest steelworks in Europe, and the critical situation of human health in the city make this application an interesting case study to assess the portability of the CSF approach, so far applied only to background stations, to industrial sites that experience high concentration variability. A comprehensive characterization of the main anthropogenic emissions of the area was carried out, with detailed treatment of dust emission by wind erosion from industrial mineral piles; a Lagrangian modelling approach was chosen to simulate PM10 dispersion patterns, to achieve a reliable and high resolution description of concentration variability around the site. The resulting representativeness area of the station is 0.067 km², fulfilling EU prescriptions for industrial stations. The comprehensive evaluation results, through the comparison with the observed data, showed good performances pointing out the reliability of the estimated concentration fields around the site and consequently of the assessment of its representativeness area.

The fractionation of a protein hydrolysate obtained from tuna processing by-products by means of a membrane cascade integrating ultrafiltration (UF) and nanofiltration (NF) membranes was proposed in order to separate and purify the protein fraction between 1 and 4 kDa, which is the most interesting for nutraceutical purposes. A simulation model, based on mass balances and empirical equations for describing permeate flux and rejection of protein fractions, was developed and complemented with a simple cost estimation model. The product purity (49.3 %) and the process yield (62.6 %) were independent of the total water consumption of the process, but high water consumptions were required to maintain the total protein content of the stream below upper bounds that assured the absence of membrane clogging. The implementation of a water recovery system, based on an additional tight NF stage, implied improvements in both environmental and economic aspects of the process.

The Tula River watershed is a water flow system that runs from the State of Mexico to the south-central part of Hidalgo State in Mexico that includes the Mezquital Valley which was originally a semiarid zone and now is an important agricultural region. We studied the River Tula watershed regarding biological, chemical, and physical parameters, describing the zooplankton species list, and the levels of five metals: arsenic, cadmium, copper, lead, and zinc, in sediments, elutriates, water column, and bioaccumulation in tilapia (Oreochromis nilotica), and some zooplanktonic species using atomic absorption. Arsenic, cadmium, and lead are present in the water column in small concentrations of different reservoirs of the Tula River watershed. Concentration of these three metals in elutriates and sediments are higher than levels in water column. The effects of the presence of these three metals in the water column, elutriates, and sediments include the following: (a) Levels of lead in muscles of tilapia make this species unsafe for human consumption, and (b) arsenic, cadmium, and lead are bioaccumulated in several zooplanktonic species. We discuss these results in the context of (a) bioaccumulation through trophic levels and (b) international and Mexican national standards regarding safe levels of contaminants in fish tissues for human consumption.

The impact of nanoparticles on fish health is still a matter of debate, since nanotechnology is quite recent. In this study, freshwater benthonic juvenile fish Prochilodus lineatus were exposed through water to three concentrations of TiO₂ (0.1, 1, and 10 μg l⁻¹) and ZnO (7, 70, and 700 μg l⁻¹) nanoparticles, as well as to a mixture of both (TiO₂ 1 μg l⁻¹ + ZnO 70 μg l⁻¹) for 5 and 30 days. Nanoparticle characterization revealed an increase of aggregate size in the function of concentration, but suspensions were generally stable. Fish mortality was high at subchronic exposure to 70 and 700 μg l⁻¹ of ZnO. Nanoparticle exposure led to decreased acetylcholinesterase activity either in the muscle or in the brain, depending on particle composition (muscle—TiO₂ 10 μg l⁻¹; brain—ZnO 7 and 700 μg l⁻¹), and protein oxidative damage increased in the brain (ZnO 70 μg l⁻¹) and gills (ZnO 70 μg l⁻¹ and mixture) but not in the liver. Exposed fish had more frequent alterations in the liver (necrosis, vascular congestion, leukocyte infiltration, and basophilic foci) and gills (hyperplasia and epithelial damages, e.g., epithelial disorganization and epithelial loss) than the control fish. Thus, predicted concentrations of TiO₂ and ZnO nanoparticles caused detectable effects on P. lineatus that may have important consequences to fish health. But, these effects are much more subtle than those usually reported in the scientific literature for high concentrations or doses of metal nanoparticles.

From April 2008 to November 2009, a field decomposition experiment was conducted to investigate the effects of sediment burial on macro (C, N) and microelement (Pb, Cr, Cu, Zn, Ni, and Mn) variations in decomposing litter of Phragmites australis in the coastal marsh of the Yellow River estuary. Three one-off sediment burial treatments [no sediment burial (0 mm year⁻¹, S₀), current sediment burial (100 mm year⁻¹, S₁₀), and strong sediment burial (200 mm year⁻¹, S₂₀)] were laid in different decomposition sites. Results showed that sediment burials showed significant influence on the decomposition rate of P. australis, in the order of S₁₀ (0.001990 day⁻¹) ≈ S₂₀ (0.001710 day⁻¹) > S₀ (0.000768 day⁻¹) (p < 0.05). The macro and microelement in decomposing litters of the three burial depths exhibited different temporal variations except for Cu, Zn, and Ni. No significant differences in C, N, Pb, Cr, Zn, and Mn concentrations were observed among the three burial treatments except for Cu and Ni (p > 0.05). With increasing burial depth, N, Cr, Cu, Ni, and Mn concentrations generally increased, while C, Pb, and Zn concentrations varied insignificantly. Sediment burial was favorable for C and N release from P. australis, and, with increasing burial depth, the C release from litter significantly increased, and the N in litter shifted from accumulation to release. With a few exceptions, Pb, Cr, Zn, and Mn stocks in P. australis in the three treatments evidenced the export of metals from litter to environment, and, with increasing burial depth, the export amounts increased greatly. Stocks of Cu and Ni in P. australis in the S₁₀ and S₂₀ treatments were generally positive, evidencing incorporation of the two metals in most sampling times. Except for Ni, the variations of C, N, Pb, Cr, Cu, Zn, and Mn stocks in P. australis in the S₁₀ and S₂₀ treatments were approximated, indicating that the strong burial episodes (S₂₀) occurred in P. australis marsh in the future would have little influence on the stocks of these elements. With increasing burial depths, the P. australis was particularly efficient in binding Cu and Ni and releasing C, N, Pb, Cr, Zn, and Mn, implying that the potential eco-toxic risk of Pb, Cr, Zn, and Mn exposure might be very serious. This study emphasized the effects of different burials on nutrient and metal cycling and mass balance in the P. australis marsh of the Yellow River estuary.

Nitrogen removal by anaerobic ammonia oxidation (anammox) of granular sludge is a globally important emerging technology. The ammonium adsorption properties of anammox granular sludge were studied at varying initial ammonium concentration and sludge concentration. Factors affecting the absorption process as temperature, pH, salinity, and metal cations were also examined. The experimental results indicated that ammonium adsorption by anammox granular sludge occurred quickly (in about 20 min). The optimal pH was 7.0 and the ammonium adsorption process was significantly affected by temperature, salinity, and metal cations. The experimental data were modeled using Langmuir, Freundlich, and Temkin adsorption isotherms and the ammonium adsorption process was fit to the Freundlich isotherm. The kinetic results indicated that the experimental data fit well to a pseudo-second-order model. Both intraparticle diffusion and boundary layer diffusion could affect the ammonium adsorption rate. The thermodynamic parameters ΔG₀, ΔH₀, and ΔS₀ were evaluated and suggested that ammonium adsorption was spontaneous and exothermic. These findings indicate that the adsorption of ammonium should be incorporated into models for nitrogen removal, particularly for the use of anammox granular sludge.

Little research has been conducted on the occurrence of pharmaceuticals and personal care products (PPCPs) in the marine environment despite being increasingly impacted by these contaminants. This article reviews data on the occurrence of PPCPs in seawater, sediment, and organisms in the marine environment. Data pertaining to 196 pharmaceuticals and 37 personal care products reported from more than 50 marine sites are analyzed while taking sampling strategies and analytical methods into account. Particular attention is focused on the most frequently detected substances at highest concentrations. A snapshot of the most impacted marine sites is provided by comparing the highest concentrations reported for quantified substances. The present review reveals that: (i) PPCPs are widespread in seawater, particularly at sites impacted by anthropogenic activities, and (ii) the most frequently investigated and detected molecules in seawater and sediments are antibiotics, such as erythromycin. Moreover, this review points out other PPCPs of concern, such as ultraviolet filters, and underlines the scarcity of data on those substances despite recent evidence on their occurrence in marine organisms. The exposure of marine organisms in regard to these insufficient data is discussed.