The removal of copper, nickel, and cobalt ions from synthetic mining wastewater was investigated in this study using micellar-enhanced ultrafiltration (MEUF). The effect of surfactant-to-metal (S/M) ratio and pH on metal rejection and permeate flux were examined. A Monte Carlo-based artificial neural network (ANN) modeling approach was proposed to predict the MEUF performance and to reveal the importance of process parameters. The results showed that model-predicted values were in agreement with experimental data (R > 0.99). S/M ratio and pH had relatively greater contributions (30–50%) to the metal rejection rate and permeate flux, whereas sampling time contributed less (10%), which indicated high MEUF efficiency. An S/M ratio of 8.5 with a pH of 8–10 was found to be the optimal condition for MEUF, under which the rejection rates of all three metals exceeded 99% and were in compliance with Canadian environmental standards. Flux decrease and concentration polarization effect were observed during the experimental procedure. Statistical analysis showed that the type of metal examined in this study did not affect MEUF performance.

Chicken feather, which is consisted of keratin, has always been abandoned as solid waste. The utilization technologies of waste keratin have been developed in electric zones and materials fields so far. Recently, numerous new types of adsorbents have been used for antibiotic removal. The chicken feather carbon is supposed to be a potential one. In this study, an activated feather carbon (AFC) was developed as the absorbent of amoxicillin (AMOX) in simulated wastewater. The micropore structures of AFC were detected by the scanning electron microscope (SEM). X-ray photoelectron spectrum (XPS) was recorded and analyzed. A BET surface area, as high as 1838.86 m²/g, was measured in this study. At the meantime, a rapid adsorption (5∼7 min) and high removal efficiency (99.63%) could be observed. The kinetics, isotherms, and thermodynamic studies indicated that the adsorption of AMOX by AFC was an exothermic physic-adsorption. The interaction between AMOX and AFC surface was supposed to be a multiple-layer adsorption process for it is well fitted with the Freundlich model. The adsorption behavior could be described by pseudo-second-order model almost perfectly in kinetic studies. In addition, effect of pH, ionic strength, and reusability properties were also discussed in this paper. The AFC was proved to be the most rapid, efficient, and economically absorbent for AMOX removal, which was effective enough under various temperatures and saline circumstances. It was also proved useful, convenient, and renewable in dealing with the tough antibiotic pollutant problems and rebuilding of antibiotic sewage treatment facilities.

The purpose of this study was to determine the different kinds and concentrations of intermediates, and investigate on the effects of contact time and ozone (O₃) doses on the removal of humic acid (HA), which is served as the main disinfection by-product (DBP) precursor. Based on that, the knowledge gap of DBPs generated was made up. The results showed that HA was the major precursor material for aldehydes and carboxylic acids. The concentrations of aldehydes increased as contact time and O₃ doses, and reached up maximum at 2~10 min but approached a plateau at the higher O₃ doses. The concentrations of formic and acetic acids increased as contact time and O₃ doses. However, aromatic acids, including protocatechuic, 3-hydroxybenzoic, and benzoic acids, declined rapidly at longer reaction time and higher O₃ doses. It was worth mentioning that aromatic acids had been rarely reported. Besides, a possible formation pathway was proposed: (a) HA was degraded into fulvic acid (FA)-like compounds; (b) FA-like compounds were further converted into aromatic acids; (c) aromatic acids were transformed into low-molecular-weight organic matters; (d) chlorine reacted with aldehydes and/or carboxylic acids by addition, hydrolysis, and decarbonylation reactions, leading to DBP formation. Furthermore, not only HA were the main DBPs precursors, but also the oxidation intermediates of HA could be the DBPs precursors, and they gave a certain amount of DBPs. Consequently, aldehydes and carboxylic acids should be under control in drinking water treatment plants.

Artificial adamite [Zn₂(AsO₄)(OH)] is a convenient structural model because it is isostructural with other rock-forming minerals in secondary ore deposits formed in cementation zones. Microbial activity in these zones accelerates mineral biogeochemical deterioration and metal release, and our results confirmed that Pseudomonas, Rhodococcus and Cupriavidus strains accelerate adamite leaching by 10 to 465 times compared to controls. Here, the Pseudomonas chlororaphis ZK-1 bacterial strain in a static 42-day cultivation proved more effective than Rhodococcus and Cupriavidus by leaching over 90% arsenic and 10% zinc from adamite in one-step in vitro. We evaluated adamite with the VESTA visualization system for electronic and structural analysis, and our results enhance understanding of zinc and arsenic biogeochemical cycles and mobilization, and highlight bacteria’s beneficial natural and biotechnological application in environmental geochemistry and biohydrometallurgy.

Mercury (Hg) poses environmental and health risks due to its global distribution and high toxicity exhibited in some of its chemical forms. Although Hg is naturally present in the environment, human activities have increased its cycling among the land, atmosphere and ocean by a factor of three to five comparing the pre-industrial period to the present day. The Torviscosa chlor-alkali plant (CAP), which operated since the beginning of twentieth century, was one of the most important Cl₂ production capacity in the Northern Italy and was responsible for an uncontrolled discharge of Hg in the surrounding area. Previous studies reported the high degree of Hg pollution in soils, river sediments and surface waters of the area, but the Hg level in the atmospheric media was never taken into consideration. In this work, an integrated approach was applied with the aim to assess the level, distribution and dispersion of gaseous elemental mercury (GEM) close to the CAP area. GEM levels were monitored by means of four surveys conducted from September 2014 to July 2015, at fixed locations and covering an area of about 10 km² (including CAP area, Torviscosa village and reclaimed land), accomplished to Hg bioaccumulation measurements in selected lichens. The results indicate that the CAP area currently represents the main source of GEM in the Friuli Venezia Giulia region. The highest levels were found close to the old factory’s buildings (more than 5000 ng m⁻³), whereas other sites are less impacted. The emission of GEM is not clearly related to the intensity of solar radiation (temperature) at the soil level; however, this latter influences the release from the old buildings employed in the past for the production activities. The most important factor driving the GEM dispersion is the wind, as confirmed by the map of lichens bioaccumulation. In this context, the GEM plume partially affects the nearby village of Torviscosa (about 1 km), but the values found were always well below the international thresholds for residential areas, thus excluding the risk of inhalation for local inhabitants.

The use of low-polarity organic solvents is widespread in cleanup/extraction processes in order to carry compounds of interest, remove interferences and separate phases, among other uses. A large number of studies have used delipidation to remove excess of lipids to analyse carbon stable isotopes in biological tissues for trophic and behavioural ecology investigations. In this context, the primary aim of this study is to assess the influence of one delipidation process on the results of total mercury (Hg) analyses and the possible use of delipidated samples from previous analyses, such as for stable isotopes, in Hg level determination. Samples of vegetation (angiosperm, lichens and mosses), invertebrates (krill and limpets), fish (marbled and black rockcod), bird liver and eggs (Antarctic, Gentoo and Adélie penguins, kelp gull, Antarctic tern, cape petrel and giant southern petrel) and pinniped tissues (Weddell seal, crabeater seal, southern elephant seal and Antarctic fur seal) were analysed for Hg before and after delipidation by cyclohexane. The difference between the two measurements ranged individually from −63 to 136% (in the moss Sanionia uncinata) and the averages ranged from −60 to 66% (in pinniped tissues). The proportion of organic Hg, which presents considerable lipophilicity, but also high affinity for sulfhydryl groups in proteins, might be responsible for such variability. Given the limitations of our study, we think it is safe to say that delipidated samples could not be used to infer total Hg values in non-delipidated ones.

The Pantanal is an extensive flooded plain, rich in biodiversity and considered a Biosphere Reserve and World Heritage Site. It has great complexity and can be divided into regions due to its each distinct characteristic. Nhecolândia is a very peculiar region because it is made up of thousands of freshwater and brackish ponds. The study objective was to evaluate the physical-chemical parameters of the Nhecolândia ponds and to analyze the vegetation indexes generated from UAV aerial photographs in order to identify what best distinguishes freshwater and brackish ponds and to differentiate study area features. The in-field and image data collection were performed on June 20, 2015. The aerial photographs were processed to obtain mosaic which served as a vegetation index basis. The indexes and wavelengths in the visible region analyses were performed for each of the area’s ponds. It was observed that bays and salines have a differentiated spectral behavior. The excess green and normalized excess green vegetation indexes presented results enough to separate freshwater from brackish ponds, plus to differentiate many study area features.

Edible muscle tissues of Solea solea, Mullus barbatus, and Sardina pilchardus marketed in Mersin were analyzed for their Cr (total), Mn, Fe, Ni, Cu, Zn, As (total), Cd, Sn, and Pb levels. Metal levels of the tissues were determined using inductively coupled plasma-mass spectrophotometric (ICP-MS) methods. Muscle levels of Cr, Mn, Fe, Ni, Cu, Zn, As, Sn, and Pb were determined as 0.19–2.80, 0.08–3.88, 0.93–25.76, 0.03–0.63, 0.01–1.96, 1.28–45.95, 0.49–25.26, 0.14–4.03, and 0.02–1.37 mg kg⁻¹ w.w., respectively. Cadmium levels were below detection limits in all the muscle samples taken. Mean metal levels of the tissues were compared with the provisional tolerable daily (PTDs) and weekly (PTWIs) intake limits. Mean metal levels taken by the consumption of analyzed tissues were below PTDs and PTWIs; hence, the fish species studied do not pose any risk for human consumption from the point of heavy metals.

This study was carried out to examine heavy metal accumulation in rice grains and brassicas and to identify the different controls, such as soil properties and soil heavy metal fractions obtained by the Community Bureau of Reference (BCR) sequential extraction, in their accumulation. In Guangdong Province, South China, rice grain and brassica samples, along with their rhizospheric soil, were collected from fields on the basis of distance downstream from electroplating factories, whose wastewater was used for irrigation. The results showed that long-term irrigation using the electroplating effluent has not only enriched the rhizospheric soil with Cd, Cr, Cu, and Zn but has also increased their mobility and bioavailability. The average concentrations of Cd and Cr in rice grains and brassicas from closest to the electroplating factories were significantly higher than those from the control areas. Results from hybrid redundancy analysis (hRDA) and redundancy analysis (RDA) showed that the BCR fractions of soil heavy metals could explain 29.0 and 46.5 % of total eigenvalue for heavy metal concentrations in rice grains and brassicas, respectively, while soil properties could only explain 11.1 and 33.4 %, respectively. This indicated that heavy metal fractions exerted more control upon their concentrations in rice grains and brassicas than soil properties. In terms of metal interaction, an increase of residual Zn in paddy soil or a decrease of acid soluble Cd in the brassica soil could enhance the accumulation of Cd, Cu, Cr, and Pb in both rice grains and brassicas, respectively, while the reducible or oxidizable Cd in soil could enhance the plants’ accumulation of Cr and Pb. The RDA showed an inhibition effect of sand content and CFO on the accumulation of heavy metals in rice grains and brassicas. Moreover, multiple stepwise linear regression could offer prediction for Cd, Cu, Cr, and Zn concentrations in the two crops by soil heavy metal fractions and soil properties.

Saline melt water from road salt applications that has percolated into a fine sandy soil in winter is rinsed out of the soil by infiltrating rainwater in the following warmer seasons. This sequence of saturated and unsaturated flow processes associated with saline water transport in a fine sandy soil was studied by simulation and exploratory laboratory experiments. Experiments in soil columns of 300-μm sand revealed that two rinses of pure water, each of one pore volume, were sufficient to reduce the salt concentration by 99% of its original value in the soil column. Simulated time variations of salt concentration in the effluent from the column agreed with experimental results. Based on simulated and experimental results, a sandy soil must become saturated to experience pore water flow in order to efficiently rinse saline snowmelt water. Depending on the saturated hydraulic conductivity and the soil depth, days, weeks, or months of freshwater infiltration in summer are needed to rinse saline melt water from an unsaturated sandy soil after road salt applications in winter. This explains findings of significant salt concentrations in surface and shallow groundwater during summer months, long after road salt application and infiltration has ceased.