Several different chemical products are used on oil platforms to aid oil-water separation during the production process. These chemicals may enter into the sea by means of production water (PW), the main discharge derived from oil and gas offshore platforms. Consequently, toxic effects may occur in the marine environment, causing reductions in wildlife numbers, degrading ecosystem functions and threatening human health. For most of these chemicals, environmental toxicity and safety thresholds in marine ecosystems have not been fully investigated as yet. In this work, a numerical-ecotoxicological approach is proposed to assess the potential environmental risk associated with the discharge of five oilfield production chemicals (deoiler, scale inhibitor, corrosion inhibitor, catalyst, dehydrating agent) from a platform in the southern Adriatic Sea (Mediterranean Sea). Their concentrations in the seawater are numerically predicted, under different seasonal conditions, starting from the real concentrations used during the production process. The predicted concentrations are then evaluated in terms of possible toxic effects in order to assess the potential risk of oilfield production chemicals discharged into the sea.

The occurrence, partitioning, and spatio-temporal distribution of seven pharmaceuticals for human use, three steroid hormones and one personal care product were determined in surface water, suspended particulate matter (SPM), and sediment of Piraí Creek and Jundiaí River (Jundiaí River Basin, São Paulo, Brazil). The maximum average detected concentrations of the compounds in the Piraí River samples were < 30 ng L⁻¹, except for caffeine (222 ng L⁻¹). In Jundiaí River samples, most of the compounds were frequently detected, wherein caffeine had the highest concentration, with maximum average concentrations of 14,050 ng L⁻¹, followed by atenolol (431 ng L⁻¹), ibuprofen (268 ng L⁻¹) and diclofenac (214 ng L⁻¹). Atenolol, propranolol, estrone, and triclosan were the contaminants most frequently detected in sediment and SPM samples. Triclosan had the highest average proportion of SPM as opposed to in the aqueous phase (> 75%). Contaminants with acid functional groups showed, in general, a lower tendency to bind to particulate matter and sediments. In addition, hydrophobicity had an important effect on their environmental partitioning. The spatial distribution of contaminants along the Jundiaí River was mainly affected by the higher concentration of contaminants in water samples collected downstream from a sewage treatment plant (STP). The results obtained here clearly showed the importance of the analysis of some contaminants in the whole water, meaning both dissolved and particulate compartments in the water, and that the partitioning is ruled by a set of parameters associated to the physicochemical characteristics of contaminants and the matrix properties of the studied, which need be considered in an integrated approach to understand the fate of emerging chemical contaminants in aquatic environments.

Size distribution, water-soluble inorganic ions (WSII), and organic carbon (OC) and elemental carbon (EC) in size-segregated aerosols were investigated during a year-long sampling in 2010 over New Delhi. Among different size fractions of PM₁₀, PM₀.₉₅ was the dominant fraction (45%) followed by PM₃–₇.₂ (20%), PM₇.₂–₁₀ (15%), PM₀.₉₅–₁.₅ (10%), and PM₁.₅–₃ (10%). All size fractions exceeded the ambient air quality standards of India for PM₂.₅. Annual average mass size distributions of ions were specific to size and ion(s); Ca²⁺, Mg²⁺, K⁺, NO₃⁻, and Cl⁻ followed bimodal distribution while SO₄²⁻ and NH₄⁺ ions showed one mode in PM₀.₉₅. The concentrations of secondary WSII (NO₃⁻, SO₄²⁻, and NH₄⁺) increased in winters due to closed and moist atmosphere whereas open atmospheric conditions in summers lead to dispersal of pollutants. NH₄⁺and Ca²⁺were dominant neutralization ions but in different size fractions. The summer-time dust transport from upwind region by S SW winds resulted in significantly high concentrations of PM₀.₉₅ and PM₃–₇.₂ and PM₇.₂–₁₀. This indicted influence of dust generation in Thar Desert and its transport is size selective in nature in downwind direction. The mixing of different sources (geogenic, coal combustions, biomass burning, plastic burning, incinerators, and vehicular emissions sources) for soluble ions in different size fractions was noticed in principle component analysis. Total carbon (TC = EC + OC) constituted 8–31% of the total PM₀.₉₅ mass, and OC dominated over EC. Among EC, char (EC1) dominated over soot (EC2 + EC3). High SOC contribution (82%) to OC and OC/EC ratio of 2.7 suggested possible role of mineral dust and high photochemical activity in SOC production. Mass concentrations of aerosols and WSII and their contributions to each size fraction of PM₁₀ are governed by nature of sources, emission strength of source(s), and seasonality in meteorological parameters.

Prediction of sediment volume and sediment load is always one of the important issues for decision-makers of watershed basins. The present study investigated the daily suspended sediment load in a watershed basin using the improved support vector machine method. Since in most of the previous studies, the coefficients of the support vector machine method had been calculated based on trial and error, in the present study, the combination of the support vector machine and the genetic algorithm is used. In the first step, the unknown parameters of the support vector machine are calculated and then, the sediment load simulation is performed. Two case studies in the present work involve two earth dams in Semnan Province called Veynakeh and Royan. Furthermore, multivariate adaptive regression spline (MARS) and MT tree model (M5T) methods are used for comparison. The results indicated that the input combination of discharge data at the current time and one, two, and three previous days has the best performance for all models. Also, the support vector machine-genetic algorithm (SVM-GA) model has a lower root mean square error (RMSE) and mean absolute error (MAE) compared to the MARS and M5T models for both stations. In addition, comparing observational data with simulation data based on the R² coefficient suggested that the SVM-GA model offers more accurate results than the other two methods. Accordingly, the SVM-GA method used in this study has a high potential for simulating sediment volume.

The rheological properties of tailings from gold, copper, and iron ore have been studied in this paper, using a self-developed large-scale type coaxial cylinder rheometer. The effect factors of the rheological properties of tailings, namely mineral types, particle size, plasma concentration, and the shear rate, and the influence they have on the viscosity and yield stress have also been studied. The test results showed that the viscosity of the tailings initially decreased with time and then became stable, while the yield stress initially increased with time and then tended to become stable. Three types of tailings all had a similar change trend with only small differences in value. The differences resulted from the varying mineral constituents of the tailings. The viscosity and the yield stress of the tailings increased as the concentration increased. As the shear rate decreased, the viscosity increased, but the yield stress also decreased. The change in magnitude of the yield stress increased as the concentration increased. It was also found that a larger particle size resulted in a higher viscosity and yield stress, the rise of which became more obvious at higher concentrations. The results were fitted using the exponential function of the Bingham model, and it was found that the coefficients of A₁ and A₂ changed significantly with the concentration, which indicated that A₁ and A₂ were largely influenced by other factors, and not only by the plasma concentration and particle diameter decisions. However, these functions of the Bingham model and the other coefficients of B₁ and B₂ were nearly constant. The three types of tailings also had a similar change trend for the fitted coefficients. There were some differences between the values associated with the type of tailings. For the same kind of tailings, the values of B₁ and B₂ were only slightly affected by other factors, while they were mainly influenced by the plasma concentration. The results of this research have provided the basic material for a stability study of a tailings dam and the analysis of movement law.

The saprotrophic fungus Alternaria alternata is widespread in the agro-environment and produces more than ten allergenic proteins, mostly protein Alt a 1. The frequency of the Alt a 1 gene was analyzed in a group of A. alternata isolates from winter wheat kernels obtained in Poland, and the effectiveness of various fungicides targeting the pathogen was evaluated. The Alt a 1 gene was identified in four of the seven tested isolates. A. alternata colonized 35.67% kernels on average, but its frequency increased in stored grain where the presence of epiphytes was noted on 23.09 to 51.38% kernels, and endophytes—in 26.21 to 42.01% of kernels. The efficacy of field-applied fungicides did not exceed 50%, despite the fact that A. alternata is highly sensitive to propiconazole, fenpropimorph, and tebuconazole under in vitro conditions. The analyzed isolates were characterized by limited sensitivity to azoxystrobin (EC₅₀ ranged from 0.505 to 1.350 μg cm⁻³) due to a mutation at codon 143 of the CYT b gene, responsible for resistance to quinone outside inhibitor fungicides, which was noted in all isolates. The spread of A. alternata can be effectively controlled with suitable fungicides and by monitoring the prevalence of pathogenic isolates in the environment.

As an inherent functional trait, body-size spectrum is widely used as an informative indicator to summarize community structures in taxon-free space. The vertical shift in the body-size spectrum of pelagic ciliates and its environmental drivers were explored at eight depth layers from the water surface to a depth of 100 m in western Arctic pelagic ecosystems. A total of 85 samples were collected at 23 sampling stations during the summer sea-ice reduction period from August 5 to August 24, 2016. Based on equivalent spherical diameter (ESD), six body-size ranks were identified, of which ranks S2 (15–25 μm), S3 (26–38 μm), S4 (39–60 μm), and S6 (79–91 μm) were the top four levels in frequency of occurrence and ranks S2 and S3 were the dominant levels in abundance. The body-size spectrum of the ciliates showed a clear vertical shift, with a significant succession among the dominant body-size units from the water surface to deeper layers in the water column. Multivariate analysis demonstrated a significant vertical variation in the body-size spectrum of the ciliates among the eight depths, which was significantly correlated with nutrients (phosphate and nitrite + nitrate) and chlorophyll a (Chl a), alone or in combination with dissolved oxygen. Four body-size diversity/distinctness indices were significantly correlated with the levels of phosphate, nitrite + nitrate, ammonium, and Chl a. Our results demonstrated that the body-size spectrum of pelagic ciliates can be shifted by environmental drivers (mainly nutrients and Chl a); thus, we suggest that it may be used to indicate water quality status on a vertical scale in the water column in deep seas.

Over the last years, the photo-Fenton process has been established as an effective, green alternative to chemical disinfection of waters and wastewaters. Microorganisms’ inactivation is the latest success story in the application of this process at near-neutral pH, albeit without clearly elucidated inactivation mechanisms. In this review, the main pathways of the combined photo-Fenton process against the most frequent pathogen models (Escherichia coli for bacteria and MS2 bacteriophage for viruses) are analyzed. Firstly, the action of solar light is described and the specific inactivation mechanisms in bacteria (internal photo-Fenton) and viruses (genome damage) are presented. The contribution of the external pathways due to the potential presence of organic matter in generating reactive oxygen species (ROS) and their effects on microorganism inactivation are discussed. Afterwards, the effects of the gradual addition of Fe and H₂O₂ are assessed and the differences among bacterial and viral inactivation are highlighted. As a final step, the simultaneous addition of both reagents induces the photo-Fenton in the bulk, focusing on the differences induced by the homogeneous or heterogeneous fraction of the process and the variation among the two respective targets. This work exploits the accumulated evidence on the mechanisms of bacterial inactivation and the scarce ones towards viral targets, aiming to bridge this knowledge gap and make possible the further application of the photo-Fenton process in the field of water/wastewater treatment.

The present experimental study reports the performance of tea waste (TW) derived adsorbent for the adsorption of sodium diclofenac (SD) from aqueous solution (SD concentration = 10–50 mg/L). The waste-derived activated carbon was prepared by chemical activation process of raw waste using H₂SO₄, KOH, ZnCl₂, and K₂CO₃ as activating agents (TW: activating agent = 1:1 by weight). Subsequently, the oven-dried material was carbonized at 600-°C temperature for 2 h. The synthesized adsorbents were porous and their Brunauer-Emmett-Teller (BET) surface area was ranged 115–865 m²/g. Among all synthesized adsorbents, the adsorbent activated by ZnCl₂ exhibited the highest adsorption capacity (= 62 mg/g), though it was much lower compared to 91 mg/g obtained with commercial activated carbon (CAC) (SD concentration = 30 mg/L, adsorbent dose = 300 mg/L and initial wastewater pH = 6.47). SD equilibrium data could be described by Langmuir isotherm adequately, while pseudo-second-order rate model showed better fit to the time based adsorption data. Low activation energy of the adsorption process suggests the reaction to be temperature independent. Thermodynamic parameters showed the spontaneous and endothermic nature of adsorption process conducted in the presence of waste derived adsorbent.

Impacts of red beet consumption both on human and animal health are subject of intense research. In particular, products that are not heat-processed contain plethora of bioactive compounds that hold promise against numerous degenerative and aging-associated diseases. However, high level of nitrates (typically more than 2 g NO₃⁻ kg⁻¹) whose health effects are perceived with reasoned objections counterbalance these benefits. Following the above, from a certain level, the increased consumption of red beet has contrary impacts, creating a limiting factor not only from the economic point of view but also in terms of beneficial compounds intake. Reduction of NO₃⁻ levels (− 35%) has been achieved by soil amendment via increased doses of biochar. The data obtained indicates that the mechanism can be explained as follows. The soil improvement reduces soil density, increases soil temperature, improves water retention, and other prerequisites for increased activity of soil microorganisms. Accelerated metabolism of soil biota turned more nitrogen from fertilizers into organic forms. Hence, less mineral nitrogen is left for red beet intake.