Environmental context Dimethyl trisulfide (DMTS) is a malodorous compound formed from decomposing algal matter and can severely compromise the quality of drinking water. The reactivity of DMTS toward cyanide was studied in aqueous solutions at environmentally relevant conditions. It was found that the half-lives of DMTS in the presence of free cyanide varied from several months to several thousand years depending on environmental conditions. Abstract Organically bound sulfur in the form of mono-, di- and polysulfide bridges constitutes a significant fraction of this element in recent and ancient sediments. In water columns of lakes, the concentrations of organo-sulfur compounds are much lower, and they are present in the form of malodorous dimethyl polysulfides. Currently, information regarding reactivity of organic polysulfides towards nucleophiles that are stronger than hydroxyl anions is lacking. In this work, the reaction kinetics of dimethyl trisulfide (DMTS) with the strong nucleophile and important environmental pollutant cyanide as a function of concentrations of reactants, pH and temperature were studied. It was found that the reaction rate constant as well as the activation energy of the reaction strongly depend on pH. The experimental data agree well with the existence of two distinct pathways: slow reaction between protonated cyanide and DMTS under acidic and neutral conditions and fast reaction between cyanide anion and DMTS under highly alkaline conditions. However, reactions of DMTS with the iron cyanide complexes hexacyanoferrate(ii) and hexacyanoferrate(iii) have no environmental significance since they are slower than the rate of DMTS decomposition. Under environmentally relevant conditions, rates of reactions of free cyanide with DMTS will be lower than the reaction with inorganic polysulfides or tetrathionate, but faster than the reaction with thiosulfate. Examples of application of kinetic parameters for calculation of rates of cyanide consumption in industrial and non-polluted natural aquatic systems as well as a protocol for quantification of organic polysulfide sulfur based on reaction with cyanide are provided.

Toxicological chemistry focuses on the toxicological aspects of all the factors severely affecting the human beings and other living organisms. Dose-response relationship is of extreme importance as it is essential to specify the normal and lethal dose along with the conditions upon which response is obtained, including dose administration interval. Toxic effects for different subjects and various chemicals generally range from totally irreversible effects to fully reversible effects. Almost all the living organisms are unavoidably and continuously exposed to xenobiotics. Removal of xenobiotics mainly depends on their rate of conversion into water soluble chemical compounds through a well-known process called “biotransformation”. For comprehensive investigations of toxicities of hydrocarbons, they can be grouped into five major categories: alkanes, unsaturated non-aromatic hydrocarbons, aromatic hydrocarbons, polycyclic aromatic hydrocarbons having multiple rings, and a mixture of hydrocarbons constituting a combination of two or more types.

The lithosphere or geosphere is a shell of rocky planet, most rigid outer layer and solid part of the earth which constitutes crust and brittle mantle. The two major types of lithosphere are continental lithosphere and oceanic lithosphere. This chapter discusses the composition and characteristics of three major types of rocks: igneous rocks, sedimentary rocks, and metamorphic rocks. Movement of lithospheric plates is known as “plate tectonics”, which is responsible for the continental drifts, volcanic activities and earthquakes. The chapter describes weathering, including physical weathering, chemical weathering, and biological weathering. It also discusses various forms of landforms and their properties and provides an introduction to soil. The brittle and relatively cool lithosphere is one of the five major spheres of the earth. Other environmental spheres are biosphere, cryosphere, hydrosphere, and atmosphere. All these spheres strongly influence the lithosphere through interactions with diverse elements like landscapes, biodiversity and ocean salinity.

Hazardous wastes have broadly been classified as U-list, P-list, K-list and F-list of hazardous wastes based on four characteristics: toxicity, reactivity, corrosivity and ignitability. Based on the sources, hazardous wastes have been divided into three categories: nuclear hazardous waste, chemical hazardous waste, and biological hazardous wastes. Solid hazardous wastes generally originate from discarded commercial products, specific industrial units and common manufacturing processes thereby exhibiting toxicity, ignitibility, reactivity and corrosivity. Any harmful material is labeled “hazardous waste” if it is toxic, reactive, corrosive and ignitable in nature. A type of wastes constituting intrinsically radioactive materials or contaminated by radiations released from different sources is called “radioactive wastes”. Treatment technologies for the management of nuclear wastes involve precipitation to bring modifications in chemical composition, ion exchange or filtration to remove radionuclides and compaction to reduce the volume of toxicants.

Environmental contextThe fate of silver nanoparticles (AgNPs) in aqueous systems could be influenced by the hydrophobicity of natural organic matter. We observed that the aggregation and dissolution of oppositely charged AgNPs were controlled by the selectivity and dynamics of sorption processes involving the nanoparticle surface and hydrophobic groups on natural organic matter. These findings will be helpful to understand the fate and effects of coated AgNPs in natural systems. AbstractThe fate of silver nanoparticles (AgNPs) released into aquatic environments is significantly affected by natural organic matter (NOM). However, current studies are still insufficient to understand interactions between NOM and AgNPs because they do not explicitly consider the heterogeneity of NOM. We investigated how NOM components with different properties (hydrophobicity, molecular weight, aromaticity, and polarity of functional groups) interact with AgNPs coated with citrate (Cit) and branched polyethylenimine (BPEI) and influence their colloidal stability and dissolution. Pony Lake fulvic acid (PLFA) selected as a model NOM was fractionated into hydrophobic (HPO) and transphilic (TPI) fractions. Sorption of PLFA molecules with a high content of polar functional groups bound to the aromatic rings onto nanoparticles was more favourable in the case of the TPI fraction, which most likely resulted in higher aggregation for both AgNPs and stronger protection of BPEI-AgNPs against dissolution compared with the HPO fraction. Additionally, in contrast to the Cit-AgNPs, resorption of Ag+ ions released from BPEI-AgNPs and/or sorption of Ag+-PLFA complexes to the nanoparticles was most likely a dynamic process, as suggested by the time-dependent changes in the molecular weight of the PLFA fractions sorbed to the BPEI-AgNP surface. These observations suggest that the accessibility of the AgNP surface for the hydrophobicity-based fractions of NOM as well as their colloidal stability and dissolution are controlled by the type and charge of coating materials and by the molecular weight, aromaticity, and content of polar functional groups of NOM.

Environmental context Contamination of surface water by micropollutants is a major environmental concern because of their high persistence and toxicity. Micropollutants are only partially removed in nanofiltration water treatment systems, encouraging the investigation of more complex systems involving partitioning with membrane materials, organic matter and ion exchange resins. This study elucidates the micropollutant partitioning mechanisms in this complex water treatment system. Abstract The accumulation of micropollutants, such as steroid hormones, in magnetic ion exchange resin-nanofiltration (MIEX-NF) poses a risk to the environmental contamination of surface water where the treated water is discharged. In this study, the partitioning of the steroid hormone estradiol (E2) with humic acid (HA), MIEX and the membrane is investigated at different feed water conditions (e.g. pH and presence of calcium). The transport and adsorption of E2 in NF is not affected significantly by the E2-HA interaction. Indeed, E2 partitions with HA between 8 % and 25 % at different pH. This is attributed to the presence of calcium ions, which reduces the number of HA molecules available to interact with E2 molecules. The calcium interference is evident especially at pH > 10, where calcite and HA precipitate to result in irreversible membrane fouling. In the hybrid MIEX-NF process, the E2-MIEX interaction occurs at all pH conditions. Approximately 40 % of the E2 total mass partitions with MIEX. This is significantly higher than E2 accumulation in NF. Since the partitioning is at least partially reversible, this poses a risk for accidental E2 release into the process streams.

Environmental context Antibiotic residues released to the environment could influence the selection of antibiotic-resistant bacteria and hence their spread within the aquatic environment. We report a multi-method approach for determining 47 antibiotics in wastewater, surface water, drinking water and groundwater. The method provides a rapid screening of water samples for common antibiotics that have the potential to alter natural bacterial populations. Abstract A simple and rapid liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS) method for the determination of 47 different antibiotics in water samples was developed. A straightforward sample preparation of aqueous samples could be established using a simple dilution step with a mixture of water and acetonitrile (+ 0.8 g L−1 ethylenediaminetetraacetic acid (EDTA)), subsequent filtration through a hydrophilised polytetrafluoroethylene (H-PTFE) syringe filter and a subsequent direct injection. The multi-analyte method presented includes substances from eleven classes of antibiotics (penicillins, cephalosporins, carbapenems, macrolide antibiotics, lincosamides, fluoroquinolones, tetracyclines, sulfonamides, glycopeptid antibiotics, oxazolidinones and nitroimidazoles). The method is characterised by a typical dynamic range from 0.01 µg L−1 to a maximum of 5 µg L−1, with good linearity regression coefficients (r2 > 0.99) and suitable recovery rates (generally from 65 ± 13 % to 117 ± 5 %) in spiked drinking water, surface water, groundwater and simulated treated wastewater. Suitable limits of quantification between 3.3 ng L−1 and 190 ng L−1 could be obtained, which are sufficient to determine low levels of antibiotic residues in the aquatic environment. The efficiency of the developed method was tested by analysing the residual concentrations of antibiotics in a small creek in Germany (‘Swistbach’). Sulfamethoxazole in combination with trimethoprim could be detected frequently, with calculated detection frequencies of 94–100 % and 29–47 %, as well as macrolide antibiotics (azithromycin (50–60 %), clarithromycin (82–94 %), clindamycin (88–100 %) and erythromycin (41–53 %). The determined concentrations were in a range between 0.01 µg L−1 and 0.43 µg L−1 downstream of the municipal wastewater treatment plants, whereas no antibiotics could be detected upstream.

Environmental context Antimony is a metalloid occurring at overall low concentrations in the Earth’s crust. Owing to anthropogenic activities, however, antimony can be found at elevated and detrimental levels in some environments. We report eco-toxicological effects of antimony in biological models, results from which can help predict antimony’s ecological and environmental impact. Abstract The aim of this work was to evaluate the effect of SbIII on cell integrity, expression of profibrotic factors and reactive oxygen species (ROS) in mouse cortical collecting duct cells (M-1 cell line). M-1 cells were incubated with SbIII for 24 h. Cell morphology and RNA expression level (connecting tissue growth factor, CTGF), α-SMOOTH MUSCLE ACTIN (α-SMA) and collagen I were analysed. The total Sb content according to each cell compartment was determined and ROS production was measured. Eighty percent of the total Sb was detected in the extracellular medium. A significant increase in ROS production and CTGF protein expression were observed at 100 μg L−1 SbIII. M-1 cells showed a non-classic epithelial cell shape at 100 μg L−1 and a reduction in the collecting duct-specific marker aquaporin-2. At 100 μg L−1, the number of collagen I-positive cells increased. At 300 μg L−1, a gross cell nuclear rupture was observed. These results demonstrate that an SbIII concentration of 100 μg L−1 is able to promote the induction of CTGF and collagen I along with the induction of ROS, which suggests a cytotoxicity of SbIII in M-1 kidney collecting duct cells.

Environmental context The fate and build-up of phosphate nutrients in aquatic environments is an urgent environmental problem affecting global water security. This study, guided by a statistical design method, optimises the flocculation properties of a biopolymer for removing orthophosphate from water. This improved technology has potential widespread applications for removal of orthophosphate from water and wastewater treatment systems. Abstract A coagulation-flocculation process was employed to remove turbidity (Ti) and orthophosphate (Pi) in aqueous media using a ferric chloride (FeCl3) and a grafted carboxymethyl chitosan (CMC) flocculant system. The amphoteric CMC-CTA flocculant was synthesised by grafting 3-chloro-2-hydroxypropyl trimethylammonium chloride (CTA) onto the biopolymer backbone of CMC. Here, CMC-CTA denotes the covalent grafting of CTA onto CMC. Optimisation of the variables for Pi and Ti removal was conducted using a jar test system based on the experimental design obtained from the response surface methodology (RSM). The Box–Behnken design was used to evaluate the individual and interactive effects of four independent variables: CMC-CTA dosage, FeCl3 dosage, pH and settling time. The RSM analysis showed that the experimental data followed a quadratic polynomial model with the following optimal conditions: [CMC-CTA] = 3.0 mg L-1, [FeCl3] = 10.0 mg L-1, pH 6.8 and settling time = 35 min. Optimum conditions led to a Pi removal of 96.4 % and turbidity removal of 96.7 % based on the RSM optimisation, in good agreement with experimental results with an initial concentration of 30.0 mg Pi L-1. The coagulation-flocculation process is characterised by a combination of electrostatic charge neutralisation, polymer bridging and a polymer adsorption mechanism.

Environmental context Nanotechnology has great potential for managing agricultural plant disease. This study compares effects of various nano and conventional copper formulations on Collembola Folsomia candida, a model arthropod often used to test soil pollutants. Although toxicity varied between formulations, with a nanopesticide showing one of the highest toxicities, the differences were mainly due to the active copper compound rather than its nano formulation. Abstract Nanotechnology has recently become a major asset in agricultural practices owing to the improvement and provision of solutions for plant disease management, especially in the form of nanopesticides. These products are considered as one of the main direct sources of nanomaterials in terrestrial ecosystems, and for that reason, it is essential to understand and evaluate their behaviour and toxicity in the environment. In addition, the panoply of similar compounds makes it difficult to accurately evaluate if different formulations may induce different effects on non-target organisms. We aim to compare the toxicity and bioavailability of different copper formulations (nano and non-nano) applied to the soil using the model organism Folsomia candida. Reproduction tests were performed in two different soils (Lufa 2.1 and 2.2) with two equilibrium times after spiking (0 and 48 h). Depending on the copper form present in the formulation, the half maximal effective concentration (EC50) values of the non-nano pesticides varied from 274 mg Cu kg-1 in Champion® to 3030 mg Cu kg-1 in Cupravit® in Lufa 2.2 and 48 h equilibrium. The nano formulation displayed one of the highest toxicities to collembolans, with an EC50 of 156 mg Cu kg-1. Regarding the soil type, a higher toxicity in Lufa 2.1 was observed probably related to the soil characteristics, namely lower pH and lower organic content, which increase the metal solubility and consequently the bioavailability. The only exception was the nanopesticide Kocide 3000®, whose toxicity was higher in Lufa 2.2. This study emphasises the importance of understanding the links between metal bioavailability and toxicity to support the more robust environmental risk assessment of different Cu fungicide formulations.