This study has assessed the influence of the origin of air mass on levels of particulate matter (PM₁₀) and chemical composition (SO₄²⁻ and NO₃⁻) in the air basin of Madrid. A data set of back-trajectories of air mass arriving to this area of study from 15 June 15 2009 to 8 July 2011 has been analyzed. Firstly, the cluster analysis statistical method has been used to group the back-trajectories into 5 sets according to the angle, direction, and speed of the air mass. Afterwards, the synoptic meteorological scenarios associated with each cluster were obtained and interpreted. Subsequently, an analysis was made on the influence of these clusters on the surface levels of particulate pollutants recorded in a regional background station (“El Atazar”), as well as in two urban background stations (“Casa de Campo” and “CIEMAT”). Finally, potential source areas of PM₁₀, SO₄²⁻, and NO₃⁻ that contributed to the increase in their background levels in the Madrid air basin were detected by analyzing residence times of trajectories. Transport of mineral desert dust is probably the main cause of the increase of regional and urban background levels of PM₁₀ in the Madrid air basin. In the case of SO₄²⁻, relatively high levels were registered, associated with air mass coming from Southern Europe and the Mediterranean Sea. In these regions, strong emissions of SO₄²⁻ are produced due to industrial combustion and maritime traffic. Otherwise, relatively high levels of NO₃⁻ were registered during meteorological situations defined by a low baric gradient in the Iberian Peninsula. This meteorological pattern favors the accumulation of emissions from local and regional sources. Besides, the main urban centers of northeastern Europe and industrial areas located in the north African coast were also identified as potential source areas of NO₃⁻. The statistical analysis of the back-trajectories by different methods and the comparison of the results obtained with observational data confirmed that numerous industrial areas in Europe and North Africa, as well as natural ones, such as deserts, had an influence on the regional and urban background levels of mass and chemical composition of particulate matter in the Madrid air basin, under the development of specific synoptic meteorological situations. Graphical abstract

The supply of potassium (K) is a strategy to increase the tolerance of plants exposed to Cd toxicity. The aim of this study was to verify the influence of K on the growth and potential of Tanzania guinea grass (Panicum maximum Jacq. cv. Tanzania (syn. Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs)) for Cd phytoextraction as well as to evaluate nutritional attributes of this grass under conditions of Cd stress. The experiment was conducted in a randomized complete block design, using a 3 × 4 factorial arrangement, with three replications. Three rates of K (0.4, 6.0, and 11.6 mmol L⁻¹) were combined with four rates of Cd (0.0, 0.5, 1.0, and 1.5 mmol L⁻¹) in nutrient solution. Two plant growth periods were evaluated. The increase in K supply to plants exposed to Cd rates of up to 1.0 mmol L⁻¹ caused increase in morphogenic and production attributes, as well as reduction in tiller mortality rate, in the second growth period. K concentrations (in both harvests) increased, while calcium and magnesium concentrations in the second harvest decreased with increasing Cd rates. The high availability of Cd (1.5 mmol L⁻¹) in the nutrient solution caused decrease in relative chlorophyll index (RCI) in both harvests. The high supply of K to plants exposed to Cd resulted in high shoot dry mass production, reducing Cd concentration in the photosynthetic tissues (which means great tolerance of the plant) and increasing the accumulation of this metal in the shoots that can be harvested. Therefore, K increases the Cd phytoextraction capacity of Tanzania guinea grass.

A new marine sediment certified reference material (IAEA 459) with very low concentrations (μg kg⁻¹) for a variety of persistent organic contaminants (POPs) listed by the Stockholm Convention, as well as other POPs and priority substances (PSs) listed in many environmental monitoring programs was developed by the IAEA. The sediment material was collected from the Ham River estuary in South Korea, and the assigned final values were derived from robust statistics on the results provided by selected laboratories which demonstrated technical and quality competence, following the guidance given in ISO Guide 35. The robust mean of the laboratory means was assigned as certified values, for those compounds where the assigned value was derived from at least five datasets and its relative expanded uncertainty was less than 40% of the assigned value (most of the values ranging from 8 to 20%). All the datasets were derived from at least two different analytical techniques which have allowed the assignment of certified concentrations for 22 polychlorinated biphenyl (PCB) congeners, 6 organochlorinated (OC) pesticides, 5 polybrominated diphenyl ethers (PBDEs), and 18 polycyclic aromatic hydrocarbon (PAHs). Mass fractions of compounds that did not fulfill the criteria of certification are considered information values, which include 29 PAHs, 11 PCBs, 16 OC pesticides, and 5 PBDEs. The extensive characterization and associated uncertainties at concentration levels close to the marine sediment quality guidelines will make CRM 459 a valuable matrix reference material for use in marine environmental monitoring programs.

Oxyfluorfen (Goal 24%EC) herbicide is widely used in agriculture for weed control. Biomphalaria alexandrina snails can be used as bioindicator of the chemical pollution in the aquatic environment. The objective of this study was to evaluate the molluscicidal activity of this herbicide on Biomphalaria alexandrina snails and how it affected its biological system. The present study revealed a molluscicidal effect of oxyfluorfen 24%EC on these snails at LC₅₀ 5.9 mg/l. After exposure of snails to the sub-lethal concentrations (LC₀, LC₁₀, or LC₂₅) of this herbicide, the survival rates, reproductive rate (R₀), and fecundity (Mₓ) of adult B. alexandrina snails were significantly decreased in comparison with the control group. Also, levels of testosterone and estradiol were decreased significantly. It caused alterations in the antioxidant system, where exposure to sub-lethal concentration of this herbicide caused significant increases in levels of lipid peroxide malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD), while it significantly decreased glutathione transferase (GST). Histopathological changes in the digestive gland included severe damage in the digestive cells, where, they lost their tips and some were degenerated, while the secretory cells increased in number. Regarding the hermaphrodite gland, there were losses of the connective tissues, irregular sperms, and the eggs degenerated. These findings concluded that B. alexandrina snails can be used as a bioindicator for pollution with pesticide in the aquatic environment.

Macro-elements (Ca, Fe, K, Mg and Na) and trace elements including some toxic (As, Be, Cd, Co, Cu, Mn, Ni, Pb, Se and Zn) were determined in edible and inedible wild-growing mushrooms (Amanita rubescens, Auricularia polytricha, Boletus edulis, Boletus mirabilis, Clavulina cristata, Helvella crispa, Lactarius deliciosus, Suillus luteus, Termitomyces microcarpus, Termitomyces reticulatus, Termitomyces clypeatus, Termitomyces umkowaanii, Amanita foetidissima, Amanita muscaria, Amanita pantherina, Aseroe rubra, Chlorophyllum molybdites, Ganoderma lucidum, Gymnopilus junonius, Hypholoma fasciculare, Lentinus villosus, Lepista caffrorum, Pycnoporus sanguineus, Panaeolus papilionaceus, Pisolithus tinctorius, Pleurotus ostreatus, Podaxis pistillaris, Russula sardonia, Scleroderma citrinum, Scleroderma michiganense). Analyses of samples were carried out using inductively coupled plasma-optical emission spectrometry. The elemental content in both edible and inedible mushrooms, in decreasing order, was found to be K >> Na > Ca > Mg > Fe > Mn > Zn > Cu > Se > Co > Ni > Be > Pb ≥ Cd > As. Our study revealed that the accumulation of metals from the soil is independent of whether mushrooms are edible or inedible as uptake is dependent on the soil quality and its environment. Edible mushroom species studied were found to be rich in Se (145–836% towards the RDA) with B. edulis being rich in it, C. cristata in Cu, S. luteus in Fe and H. crispa in Zn, and all contained low concentrations of toxic metals making them suitable for human consumption.

Landfill leachate is generally transferred to in situ facilities for advanced treatment by using a pipe system. Because of its harmful and complex compounds, leachate may react with pipe materials, leading to corrosion and scaling. This experimental study uses typical PVC pipe material and investigates its anti-corrosion performance by placing the material samples into different aged leachates. By evaluating the changes in different experimental parameters, including calcium, magnesium, and chloride ion concentration, oxidation-reduction potential, dissolved oxygen, and pH, combined with a characterization of the material properties, we infer the main causes of pipe scaling-corrosion. Results show that the scaling is more intense in the younger leachate, and the concentration of calcium ions is the dominant influencing factor. The scaling might be resulted from joint actions of chemical precipitation and microbial metabolic activities. It is expected the study to provide useful insights into taking effective actions on anti-clogging, and enhance pipes design by selection of appropriate materials for future modification.

Petroleum contamination and its remediation via plant-based solutions have got increasing attention by environmental scientists and engineers. In the current study, the physiological and growth responses of two diesel-tolerant plant species (tolerance limit: 1500–2000 mg/kg), Italian ryegrass (Lolium multiflorum) and Birdsfoot trefoil (Lotus corniculatus), have been investigated in vegetable oil– and diesel oil–amended soils. A long-term (147-day) greenhouse pot experiment was conducted to differentiate the main focus of the study: physical and chemical effects of oil (vegetable and diesel) in freshly spiked soils via evaluating the plant performance and hydrocarbon degradation. Moreover, plant performance was evaluated in terms of seed germination, plant shoot biomass, physiological parameters, and root biomass. Addition of both diesel oil and vegetable oil in freshly spiked soils showed deleterious effects on seedling emergence, root/shoot biomass, and chlorophyll content of grass and legume plants. Italian ryegrass showed more sensitivity in terms of germination rate to both vegetable and diesel oil as compared to non-contaminated soils while Birdsfoot trefoil reduced the germination rate only in diesel oil–impacted soils. The results of the current study suggest that both physical and chemical effects of oil pose negative effects of plant growth and root development. This observation may explain the phenomenon of reduced plant growth in aged/weathered contaminated soils during rhizoremediation experiments.

In this paper, the developmental toxicity and apoptosis in zebrafish (Danio rerio) embryos induced by 0.01, 0.05, and 0.10-Gy γ-ray irradiation were investigated and verified by single cell gel electrophoresis, acridine orange staining, flow cytometry, transmission electron microscopy, digital gene expression sequencing, and Western blot analysis. DNA damage, deformity rates, and apoptosis of zebrafish embryos were found to increase significantly with the increase of irradiation dose, and survival and hatching rates significantly decreased when the irradiation dose exceeds 0.10 and 0.05 Gy, respectively. Exposure to 0.10-Gy γ-ray irradiation resulted in the swelling of cell mitochondria of zebrafish embryos and changes in their intracellular vacuoles. mRNA and protein expression levels of Shh (sonic hedgehog 19 KDa) and Smo (smoothened 86 KDa) of Hh signaling pathway associated with the development of early embryos significantly increased with the increase of irradiation dose. Expression of the AKT (56 KDa) and PiK3r3 (55 KDa) genes, which are anti-apoptotic and involved with the PI3K/Akt signaling pathway, significantly decreased, while expression of the bada gene, which is pro-apoptotic, significantly increased. The results show that γ-ray irradiations of 0.01 and 0.05 Gy can induce developmental toxicity and apoptosis in zebrafish embryos via Hh and PI3K/Akt signaling pathways, respectively.

Greenhouse cultivation is expanding in China due to high production efficiency and greater economic benefits. Although the accumulation of soil salinity and nutrients has been observed in greenhouse cultivation areas, the linkage between soil salinity, soil major ions, and farm practices is not clear in China. Few studies have examined soil salinity accumulated in soil layers; thus, a broad investigation is needed in order to understand the potential causes of soil salinity in greenhouse soil. In this study, a short review was given to show the salt contents and the major ion under greenhouse conditions in China. Then, we analyzed a total of 132 soil samples from different parts of China in terms of their soil major ions and nutrient components and investigated the relevant farm practices. Based on survey data from three different types of cultivation areas (open farmland, plastic greenhouses, and multispan greenhouses), we found that cultivation in both greenhouse types resulted in a significant increase in salt content and a decrease in soil pH values, a pattern not shown in open farmland. The linkage between soil salinity and cultivation type was confirmed by soil salinity classification. The proportion of each ion in the soil salt differs significantly between the different management methods, but the variation range of the main ions ranged from − 23.3 to 225.6% for multispan greenhouses and − 22.6 to 430.5% for plastic greenhouses. In addition, the salt source in greenhouses is not unique to those methods, suggesting that different growing practices cause the differences in ion concentration. Removing greenhouse covers during the rainy season can avoid further accumulations of salt, but the subsequent rinsing of soil can lead to the deeper salt accumulations. In addition, increasing salt content may lead to decreasing pH once the natural salt balance is altered. These results show that the soil salinization produced by greenhouse cultivation cannot be ignored.

Contamination caused by leakage at gas stations leads to possible exposure of the general population when in contact with contaminated water and soil. The present study aimed to evaluate the reproductive effects of exposure of adult male rats to gasohol and evaluate the performance of machine learning (ML) algorithms for pattern recognition and classification of the exposure groups. Rats were orally exposed to 0 (control), 16 (EA), 160 (EB), or 800 mg kg⁻¹ bw day⁻¹ of gasohol (EC), for 30 consecutive days. Sperm quality of the groups exposed to two higher doses was reduced in comparison to the control group. The sperm parameters decreased were: daily sperm production, sperm number in the caput/corpus epididymis, progressive motility, mitochondrial activity, and acrosomal membrane integrity. Sperm transit time in the epididymis cauda and sperm isolated head were increased in EB and EC. Sertoli cells number was decreased in these groups, but their support capacity was maintained. ML methods were used to identify patterns between samples of control and exposure groups. The results obtained by ML methods were very promising, obtaining about 90% of accuracy. It was concluded that the exposure of rats to different doses of gasohol impair spermatogenesis and sperm quality, with a recognizable classification pattern of exposure groups at ML.