Elevated levels of particulate matter (PM) in urban atmospheres are one of the major environmental challenges of the Anthropocene. To effectively lower those levels, identification and quantification of sources of PM is required. Biomonitoring methods are helpful tools to tackle this problem but have not been fully established yet. An example is the sampling and subsequent analysis of spider webs to whose adhesive surface dust particles can attach. For a methodical inspection, webs of orb-weaving spiders were sampled repeatedly from 2016 to 2018 at 22 locations in the city of Jena, Germany. Contents of Ag, Al, As, B, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sb, Si, Sn, Sr, Th, Ti, V, Y, Zn and Zr were determined in the samples using inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) after aqua regia digestion.Multivariate statistical methods were applied for a detailed evaluation. A combination of cluster analysis and principal component analysis allows for the clear identification of three main sources in the study area: brake wear from car traffic, abrasion of tram/train tracks and particles of geogenic origin. Quantitative source contributions reveal that high amounts of most of the metals are derived from a combination of brake wear and geogenic particles, the latter of which are likely resuspended by moving vehicles. This emphasizes the importance of non-exhaust particles connected to road traffic.Once a source identification has been performed for an area of interest, classification models can be applied to assess air quality for further samples from within the whole study area, offering a tool for air quality assessment. The general validity of this approach is demonstrated using samples from other locations.

The influence of common textile finishes on cotton fabrics on the generation of microfibers during laundering was assessed. Microfiber release was determined to be in the range of 9000–14,000 particles per gram of cotton fabric. Cotton knitted fabrics treated with softener and durable press generate more microfibers (1.30–1.63 mg/g fabric) during laundering by mass and number than untreated fabric (0.73 mg/g fabric). The fabrics treated with softener generated the longest average microfiber length (0.86 mm), whereas durable press and water repellent treatments produced the shortest average microfiber length (0.62 and 0.63 mm, respectively). In general, the changes in the mechanical properties of the fibers and fabrics due to the finishing treatments are the main factor affecting the microfiber release. The abrasion resistance of the fabrics decreases for durable press treatments and water repellent treatments due to the brittleness in the structure originated by the crosslinking treatment. In the case of the softener treatment, the fabric surface is soft and smooth decreasing the friction coefficient between fibers favoring the fibers loosening from the textile and resulting in a high tendency for fuzz formation and microfiber release. These findings are useful for the textile industry in the design and selection of materials and treatments for the reduction of synthetic or natural microfiber shedding from textiles.

Apis mellifera is a pollinator insect model in pesticide risk assessment tests for bees. However, given the economic and ecological importance of stingless bees such as Melipona scutellaris in the Neotropical region, as well as the lack of studies on the effect of insecticides on these bees, toxicity tests for stingless bees should be carried out to understand whether insecticides affect both species of bees in the same manner. Thus, the present study quantified the differential sensitivity of the bees M. scutellaris and A. mellifera to the oral ingestion of the insecticide thiamethoxam by determining the mean lethal concentration (LC₅₀), mean lethal time (LT₅₀), and their effect on the insecticide target organ, the brain. The results showed that the stingless bee is more sensitive to the insecticide than A. mellifera, with a lower LC₅₀ of 0.0543 ng active ingredient (a.i.)/μL for the stingless bee compared to 0.227 ng a.i./μL for A. mellifera. When exposed to a sublethal concentration, morphological and ultrastructural analyses were performed and evidenced a significant increase in spaces between nerve cells of both species. Thus, A. mellifera is not the most appropriate or unique model to determine the toxicity of insecticides to stingless bees.

Pfaffia glomerata is a candidate for the remediation of heavy metal-contaminated soil, but phytoremediation efficiency requires enhancement. In this study, we evaluated how application of DA-6, EDTA, or CA affected the growth and heavy metal accumulation of P. glomerata and soil microorganisms. We found that P. glomerata removed more Cd and Zn than Pb or Cu from contaminated soil. When compared to the control, application of DA-6, CA, or CA + DA-6 increased plant biomass and increased stem Cd concentration by 1.28-, 1.20-, and 1.31-fold respectively; increased leaf Cd concentration by 1.25-, 1.28-, and 1.20-fold, respectively; and increased the total quantity of Cd extracted by 1.37-, 1.37-, and 1.38-fold, respectively. When compared to the control, application EDTA or EDTA + DA-6 significantly increased the soil available metal and Na concentrations, which harmed plant growth. Application of EDTA or EDTA + DA-6 also significantly decreased the Cd concentration in roots and stems. 16S rRNA high-throughput sequencing analysis revealed that application of EDTA or CA alone to soil significantly reduced the richness and diversity of soil bacteria, while foliar spraying of DA-6 combined with EDTA or CA slightly alleviated this reduction. EDTA or CA addition significantly changed the proportion of Actinobacteria and Proteobacteria. In addition, EDTA or CA addition caused changes in soil properties (e.g. heavy metal availability, K concentration, Na concentration, soil pH, soil CEC, and soil DOC concentration) that were associated with changes in the bacterial community. EDTA addition mainly affected the soil bacterial community by changing soil DOC concentration, the soil available Pb and Na concentration, and CA addition mainly affected the soil bacterial community by changing the soil available Ca concentration.

Soil-borne diseases have become increasingly problematic for farmers producing crops intensively under protected agriculture. Although soil fumigants are convenient and effective for minimizing the impact of soil-borne disease, they are most often detrimental to beneficial soil microorganisms. Previous research showed that bio-activation of soil using biological control agents present in biofertilizers or organic fertilizers offered promise as a strategy for controlling soil-borne pathogens when the soil was bio-activated after fumigation. Our research sought to determine how bio-activation can selectively inhibit pathogens while promoting the recovery of beneficial microbes. We monitored changes in the soil’s physicochemical properties, its microbial community and reductions in soil-borne pathogens. We found that the population density of Fusarium and Phytophthora were significantly reduced and tomato yield was significantly increased when the soil was bio-activated. Soil pH and soil catalase activity were significantly increased, and the soil’s microbial community structure was changed, which may have enhanced the soil’s ability to reduce Fusarium and Phytophthora. Our results showed that soil microbial diversity and relative abundance of beneficial microorganisms (such as Sphingomonas, Bacillus, Mortierella and Trichoderma) increased shortly after bio-activation of the soil, and were significantly and positively correlated with pathogen suppression. The reduction in pathogens may have been due to a combination of fumigation-fertilizer that reduced pathogens directly, or the indirect effect of an optimized soil microbiome that improved the soil’s non-biological factors (such as soil pH, fertility structure), enhanced the soil’s functional properties and increased tomato yield.

Root-triggered microscale variations in O₂ distribution in the rhizosphere of young Phragmites australis are important for nutrient removal in sediments. In this study, the micro-scale O₂ dynamics and the small-scale changes of soluble reactive phosphorus (SRP) and ammonium (NH₄⁺) in the rhizosphere of P. australis were investigated using planar optodes and high-resolution dialysis (HR-Peeper), respectively. Results suggested that root O₂ leakage has a highly variable distribution depending on the stage of root growth, the site of O₂ leakage gradually shift from the entire emerging main roots to the main root tip and subsequently shifted the emerging lateral roots. The O₂ concentration increased in the rhizosphere with increasing light intensity and O₂ levels in the overlying water. Continuous O₂ release from the lateral roots causes the formation of iron plaque on the surface of lateral roots, which reduce the mobility of P by adsorption of iron plaque in the rhizosphere. The oscillation of oxic-anoxic root zones improves nitrogen removal through the processes of anammox, heterotrophic denitrification and nitrification. This work from the micro-scale demonstrates that the O₂ concentration is the spatio-temporal variations in the rhizosphere, and it presents an important role for nutrient removal in sediments.

Biochar is a promising immobilizing agent of trace elements (TEs) in contaminated soils. However, several contradictory results have been reported regarding the potential of biochar to immobilize arsenic (As), chromium (Cr), and nickel (Ni) in contaminated soils. We conducted a meta-analysis on the published papers since 2006 until 2019 to examine the effects of biochar on the chemical (im)mobilization of As, Cr, and Ni in contaminated soils and to elucidate the major factors that control their interactions with biochar in soil. We synthesized 48 individual papers comprised of a total of 9351 pairwise comparisons and used the statistical tool of Cohen's d as an appropriate effect size for the comparison between means. We found that the application of biochar often increased the As mobilization in soils. Important variables that modulated the biochar effects on As mobilization in soil were pyrolysis temperature and time (ranging between 8 and 16 times when T > 450 °C and t > 1hr), organic matter (7–16 times when SOM<3%) and further site conditions. In contrast to As, biochar efficiently immobilized Cr and Ni in contaminated soils. The extent of the Cr and Ni immobilization was determined by the feedstock (Cr: 7–18 times for agricultural residue-derived biochar; Ni: 13–32 times for woody biomass-derived biochar). Our meta-analysis provides a compilation on the potential of different types of biochar to reduce/increase the mobilization of As, Cr, and Ni in various soils and under different experimental conditions. This study provides important insights on factors that affect biochar's efficiency for the (im)mobilization of As, Cr, and Ni in contaminated soils. While biochar effectively immobilizes Cr and Ni, a proper management of As-polluted soils with pristine biochar is still challenging. This limitation might be overcome by modification of biochar surfaces to exhibit higher surface area and functionality and active sites for surface complexation with TEs.

Phosphogypsum (PG) is disposed worldwide in large stacks usually placed in coastal zones, as in the case of Huelva (SW of Spain), where around 100 Mt of PG are stored on the salt marshes of the Tinto River estuary covering a surface of about 1000 ha. This management generates the weathering of PG, and due to its high acidity (pH ≈ 2) and pollutant load can provoke significant emissions into their surroundings. In this work were evaluated by laboratory experiments the effects of pH increase in the behaviour of heavy metals and natural radionuclides during the mixing of phosphogypsum leachates with seawater.The acidic phosphogypsum leachates showed concentrations of heavy metals from two to three orders of magnitude higher than natural continental waters, and natural radionuclides (U-isotopes and ²¹⁰Po) from four to five orders of magnitude higher than unperturbed aquatic systems. Major elements and some heavy metals as Mn, Ni, Cd, As, Sb and Co showed a conservative behaviour during the neutralisation of the leachates with seawater, remaining in the liquid phase, while other ones as Al, Fe, Cr, Zn, Cu, Pb precipitated and/or were adsorbed onto the solid phase. The U-isotopes and ²¹⁰Po showed a clear non-conservative behaviour probably due to coprecipitation/adsorption processes onto the formed precipitates, but while ²¹⁰Po reached a total removal at pH ≈ 7, U- isotopes after a total removal at pH ≈ 5 returned into the liquid phase due to redissolution/desorption processes at near neutral pH.The formed precipitates, mainly composed by iron phosphates particles, showed heavy metal and natural radionuclide concentrations from one to three orders of magnitude higher than unperturbed soils. All these facts demonstrate the serious environmental impact produced by the PG stacks into their surroundings and the urgency of effective restoration measures.

Characteristics and sources of ambient particle elements in urban Beijing were studied by hourly observations in two size fractions (PM₁₀ and PM₂.₅) during November and December 2017 using an online multi-element analyzer. The reconstructed oxide concentrations of 24 elements (from Al to Pb) comprise an appreciable fraction of PM₁₀ and PM₂.₅, accounting for 37% and 17%, respectively on average. We demonstrate the benefit of using high-time-resolution chemical speciation data in achieving robust source apportionment of the total elemental PM₁₀ (PM₁₀ₑₗ) and elemental PM₂.₅ (PM₂.₅ₑₗ) mass using positive matrix factorization (PMF). Biomass burning, coal combustion, secondary sulfate, industry, non-exhaust traffic and dust were identified in both size fractions (with varying relative concentrations), which accounted on average for 4%, 12%, 5%, 2%, 14%, and 63%, respectively to the total PM₁₀ₑₗ, and 14%, 35%, 21%, 6%, 12% and 12%, respectively to the total PM₂.₅ₑₗ. Biomass burning and coal combustion exhibited higher concentrations during haze episodes of the heating season. In contrast, secondary sulfate and industry contributed more to haze episodes during the non-heating season. The fractional contribution of dust was mostly high during clean days, while the fractional non-exhaust traffic emission contribution was similar throughout the measurement period. The non-exhaust traffic emissions contributed locally, while the remaining sources were dominated by neighboring areas. Furthermore, trajectory analysis showed that the origin of the industrial sources roughly agreed with the locations of the main point sources. Overall, this work provides detailed information on the characteristics of the elements during different haze events during heating and non-heating seasons.

BPA is chemical pollutant of very high concern due to its toxicity to the environment and risks for human health. Environmental concern consists in BPA entrance into aquatic ecosystems due to acute and chronic toxicity to invertebrates and vertebrates. This study aimed to determine acute BPA toxicity to tropical estuarine-marine species of four trophic levels and integrate BPA toxicity values using species sensitivity distribution (SSD) analysis. Our hypothesis is that BPA toxicity increases towards higher trophic levels. Microalga (Tetraselmis sp.), zooplanktonic grazer (Artemia salina), deposit-feeder invertebrate (Heleobia australis), and omnivorous fish (Poecilia vivipara) were chosen as experimental models. Tetraselmis sp. showed the highest BPA tolerance, without a concentration-dependent response. Species sensitivity have increased from A. salina (LC₅₀,₉₆ₕ = 107.2 mg L⁻¹), followed by H. australis (LC₅₀,₉₆ₕ = 11.53.5 mg L⁻¹), to P. vivipara (LC₅₀,₉₆ₕ = 3.5 mg L⁻¹). Despite the toxicity hierarchy towards trophic levels, which partially supported our hypothesis, SSD did not evidence a clear pattern among estuarine-marine trophic groups. Our study disclosed the sensitivity of not yet investigated species to BPA and, in an integrative way, highlighted BPA toxic effects at different trophic levels. Although estimated acute hazardous concentration (HC5 = 1.18 mg L⁻¹) for estuarine and marine species was higher than environmentally relevant concentrations, sublethal adverse effects induced by BPA exposure may lead to unbalances in population levels and consequently affect the ecological functioning of tropical coastal systems.