The majority of plastics present in the marine environment are microplastics (MPs, <5 mm). Suspension filter feeders are susceptible species to MPs ingestion. Once ingested MPs can be eliminated packed in fecal pellets, or they can be accumulated within tissues, and likely be transferred along the food web. The research on MPs is hampered by the difficulty on their quantification and the lack of standardized methodologies. Indeed, limited information exits about the capacity of marine organisms to ingest, accumulate and eliminate MPs. In this work we investigated the uptake, elimination and accumulation of MPs (irregularly shaped particles of high density polyethylene, ≤22 μm) in mussel. Mussels were exposed to two concentrations of MPs (2 and 4 mm3 l−1), and their uptake, elimination and accumulation in digestive gland was investigated. The results showed that the uptake of MPs increased at the high concentration tested, and that mussels cleared MPs at the same extent than a food item (microalgae) of similar size. Small MPs (2–4 μm) were less efficiently cleared than the larger ones. Large MPs (>10 μm) were faster eliminated than the smaller ones. The global balance showed that after 6 days of depuration mussels eliminated ≈85% of the MPs cleared, and that ≈2–6% of the MPs cleared remained in the digestive gland, essentially those <6 μm. We recorded a long retention time for MPs, contrasting with the lower times assumed to be necessary to empty mussel's gut before quantifying MPs. Our study emphasized the gap of knowledge on the feeding behaviour of mussels in relation to MPs, and the necessity to investigate it in different marine species, and under different exposure scenarios.

Microplastics (MPs) are an emerging contaminant and are confirmed to be ubiquitous in the environment. Adverse effects of MPs on aquatic organisms have been widely studied, whereas little research has focused on soil invertebrates. We exposed the soil springtail Folsomia candida to artificial soils contaminated with polyethylene MPs (<500 μm) for 28 d to explore the effects of MPs on avoidance, reproduction, and gut microbiota. Springtails exhibited avoidance behaviors at 0.5% and 1% MPs (w/w in dry soil), and the avoidance rate was 59% and 69%, respectively. Reproduction was inhibited when the concentration of MPs reached 0.1% and was reduced by 70.2% at the highest concentration of 1% MPs compared to control. The half-maximal effective concentration (EC₅₀) value based on reproduction for F. candida was 0.29% MPs. At concentrations of 0.5% dry weight in the soil, MPs significantly altered the microbial community and decreased bacterial diversity in the springtail gut. Specifically, the relative abundance of Wolbachia significantly decreased while the relative abundance of Bradyrhizobiaceae, Ensifer and Stenotrophomonas significantly increased. Our results demonstrated that MPs exerted a significant toxic effect on springtails and can change their gut microbial community. This can provide useful information for risk assessment of MPs in terrestrial ecosystems.

Numerous recent studies have underlined the crucial players of noncoding RNAs (ncRNAs), i.e., microRNAs(miRNAs), long noncoding RNAs(lncRNAs) and circle RNAs(circRNAs) participating in genotoxic responses induced by a wide variety of environmental genotoxicants consistently. Genotoxic-derived ncRNAs provide us a new epigenetic molecular–ecological network (MEN) insights into the underlying mechanisms regarding genotoxicant exposure and genotoxic effects, which can modify ncRNAs to render them “genotoxic” and inheritable, thus potentially leading to disease risk via epigenetic changes. In fact, the spatial structures of ncRNAs, particularly of secondary and three-dimensional structures, diverse environmental genotoxicants as well as RNA splicing and editing forma dynamic pool of ncRNAs, which constructs a MEN in cells together with their enormous targets and interactions, making biological functions more complicated. We nonetheless suggest that ncRNAs have both beneficial(positive) and harmful(negative) effects, i.e., are “double-edged” in regulating genotoxicant toxic responses. Understanding the “double-edged” effects of ncRNAs is of crucial importance for our further comprehension of the pathogenesis of human diseases induced by environmental toxicants and for the construction of novel prevention and therapy targets. Furthermore, the MEN formed by ncRNAs and their interactions each other as well as downstream targets in the cells is important for considering the active relationships between external agents (environmental toxicants) and inherent genomic ncRNAs, in terms of suppression or promotion (down- or upregulation), and engineered ncRNA therapies can suppress or promote the expression of inherent genomic ncRNAs that are targets of environmental toxicants. Moreover, the MEN would be expected to be would be applied to the mechanistic explanation and risk assessment at whole scene level in environmental genotoxicant exposure. As molecular biology evolves rapidly, the proposed MEN perspective will provide a clearer or more comprehensive holistic view.

Light-absorbing organic carbon (OC), also referred to as “brown carbon” (BrC), has been intensively investigated in atmospheres impacted by biomass burning. However, other BrC sources (e.g., secondary formation in the atmosphere) are rarely studied in ambient aerosols. In the current work, forty-five PM₂.₅ filter samples were collected in Research Triangle Park (RTP), NC, USA from June 1st to July 15th, 2013. The bulk carbonaceous components, including OC, elemental carbon (EC), water soluble OC (WSOC), and an array of organic molecular markers were measured; an ultraviolet/visible spectrometer was used to measure the light absorption of methanol extractable OC and WSOC. The average light absorption per OC and WSOC mass of PM₂.₅ samples in summer RTP are 0.36 ± 0.16 m² gC⁻¹ and 0.29 ± 0.13 m² gC⁻¹, respectively, lower than the ambient aerosol samples impacted by biomass burning and/or fossil fuel combustion (0.7–1.6 m² gC⁻¹) from other places. Less than 1% of the aqueous extracts absorption is attributed to the light-absorbing chromophores (nitroaromatic compounds) identified in this work. To identify the major sources of BrC absorption in RTP in the summer, Positive Matrix Factorization (PMF) was applied to a dataset containing optical properties and chemical compositions of carbonaceous components in PM₂.₅. The results suggest that the formation of biogenic secondary organic aerosol (SOA) containing organosulfates is an important BrC source, contributing up to half of the BrC absorption in RTP during the summertime.

This work presents the main results of two experimental campaigns carried out in summer and winter seasons in a complex pollution hotspot near a large park, El Retiro, in Madrid (Spain). These campaigns were aimed at understanding the microscale spatio-temporal variation of ambient concentration levels in areas with high pollution values to obtain data to validate models on the effect of urban trees on particulate matter concentrations.Two different measuring approaches have been used. The first one was static, with instruments continuously characterizing the meteorological variables and the particulate matter concentration outside and inside the park. During the summer campaign, the particulate matter concentration was clearly influenced by a Saharan dust outbreak during the period 23 June to 10 July 2016, when most of the particulate matter was in the fraction PM₂.₅₋₁₀. During the winter campaign, the mass concentrations were related to the meteorological conditions and the high atmospheric stability.The second approach was a dynamic case with mobile measurements by portable instruments. During the summer campaign, a DustTrak instrument was used to measure PM₁₀ and PM₂.₅ in different transects close to and inside the park at different distances from the traffic lane. It was observed a decrease in the concentrations up to 25% at 20 m and 50% at 200 m. High PM₁₀ values were linked to dust resuspension caused by recreational activities and to a Saharan dust outbreak. The highest PM values were measured at the Independencia square, an area with many bus stops and high traffic density. During the winter campaign, three microaethalometers were used for Black Carbon measurement. Both pollutants also showed a reduction in their concentrations when moving towards inside the park. For PM₁₀ and PM₂.₅, reductions up to 50% were observed, while for BC this reduction was smaller, about 20%.

Degradation of metolachlor in surface soil is extremely important to its potential mobility and overall persistence. In this study, the effects of earthworms (Eisenia fetida) on the degradation of metolachlor at two concentration levels (5 and 20 mg kg⁻¹) in soil were investigated via the column experiment. The degradation kinetics of metolachlor indicate that addition of earthworms enhances metolachlor degradation significantly (P < 0.05), with the enhanced degradation rate of 30% and 63% in the low and high concentration treatments at the 15th day, respectively. Fungi rather than bacteria are primarily responsible for metolachlor degradation in soil, and earthworms stimulate metolachlor degradation mainly by stimulating the metolachlor-degrading functional microorganisms and improving fungal community structure. Earthworms prefer to promote the possible fungal degraders like order Sordariales, Microascales, Hypocreales and Mortierellales and the possible bacteria genus Rubritalea and strengthen the relationships between these primary fungi. Two metabolites metolachlor oxanilic (MOXA) and moetolachlor ethanesulfonic acid (MESA) are detected in soil and earthworms in the high concentration treatments. Earthworms stimulate the formation of MOXA and yet inhibit the formation of MESA in soil. Another metabolite metolachlor-2-hydroxy (M2H) is also detected in earthworms, which is reported firstly. The study provides an important information for the remediation of metolachlor-polluted soil.

The capacity of biochar to take up heavy metals from contaminated soil and water is influenced by the pyrolysis temperature. We have prepared three biochar samples from Jerusalem artichoke stalks (JAS) by pyrolysis at 300, 500 and 700 °C, denoted as JAS300, JAS500, and JAS700, respectively. A variety of synchrotron-based techniques were used to assess the effect of pyrolysis temperature on the molecular properties and copper (Cu) sorption capacity of the samples. The content of oxygen-containing functional groups in the biochar samples decreased, while that of aromatic structures and alkaline mineral components increased, with a rise in pyrolysis temperature. Scanning transmission X-ray microscopy indicated that sorbed Cu(II) was partially reduced to Cu(I), but this process was more evident with JAS300 and JAS700 than with JAS500. Carbon K-edge X-ray absorption near edge structure spectroscopy indicated that Cu(II) cations were sorbed to biochar via complexation and Cu-π bonding. With rising pyrolysis temperature, Cu(II)-complexation weakened while Cu-π bonding was enhanced. In addition, the relatively high ash content and pH of JAS500 and JAS700 facilitated Cu precipitation and the formation of langite on the surface of biochar. The results of this investigation will aid the conversion of halophyte waste to useable biochar for the effective remediation of Cu-contaminated soil and water.

Eggs from mature Chinook (Oncorhynchus tshawytscha) and Coho (Oncorhynchus kisutch) salmon were collected between 2004 and 2014 from the Salmon River fish hatchery in Altmar, New York. The egg samples were analyzed for seventeen polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), as well as four dioxin-like polychlorinated biphenyls (DL-PCBs) using USEPA methods 1613 and 1668. Salmonid eggs were chosen as a tissue of interest since salmon feed at all trophic levels of the food web as they grow, and spawn in a narrow range of ages providing consistent, representative, and temporal samples of contaminant exposure. First-order decay models indicate decreasing trends for all select contaminants in both species, expressed by a toxic equivalence (TEQ) half-life (t₁/₂) of 11 years in Chinook and Coho eggs. No significant statistical difference in contaminant elimination rates were noted between species. TEQ elimination rates for Coho and Chinook eggs were not significantly different (p > 0.05) when compared with published Lake Ontario whole-fish lake trout elimination rates. Our research demonstrates that salmonid eggs are an effective means to assess PCDD, PCDF, and DL-PCB exposures and long-term trends in the Great Lakes.

The impact of commonly-used livestock antibiotics on soil nitrogen transformations under varying redox conditions is largely unknown. Soil column incubations were conducted using three livestock antibiotics (monensin, lincomycin and sulfamethazine) to better understand the fate of the antibiotics, their effect on nitrogen transformation, and their impact on soil microbial communities under aerobic, anoxic, and denitrifying conditions. While monensin was not recovered in the effluent, lincomycin and sulfamethazine concentrations decreased slightly during transport through the columns. Sorption, and to a limited extent degradation, are likely to be the primary processes leading to antibiotic attenuation during leaching. Antibiotics also affected microbial respiration and clearly impacted nitrogen transformation. The occurrence of the three antibiotics as a mixture, as well as the occurrence of lincomycin alone affected, by inhibiting any nitrite reduction, the denitrification process. Discontinuing antibiotics additions restored microbial denitrification. Metagenomic analysis indicated that Proteobacteria, Bacteroidetes, Actinobacteria, and Chloroflexi were the predominant phyla observed throughout the study. Results suggested that episodic occurrence of antibiotics led to a temporal change in microbial community composition in the upper portion of the columns while only transient changes occurred in the lower portion. Thus, the occurrence of high concentrations of veterinary antibiotic residues could impact nitrogen cycling in soils receiving wastewater runoff or manure applications with potential longer-term microbial community changes possible at higher antibiotic concentrations.

That an alteration of the intestinal permeability is associated with gut barrier function has been increasingly evident, which plays an important role in human and animal health. Bisphenol A (BPA), an industrial compound used worldwide, has recently been classified as an environmental pollutant. One of our earlier studies has demonstrated that BPA disrupts the intestinal barrier function by inducing apoptosis and inhibiting cell proliferation in the human colonic epithelial cells line. In this study, we investigated the effects of dietary BPA uptake on the colonic barrier function in mice, as well as the intestinal permeability. Dietary BPA uptake was observed to destroy the morphology of the colonic epithelium and increase the pathology score. The levels of endotoxin, diamine peroxidase, D-lactate, and zonulin were found to have been significantly elevated in both plasma and colonic mucosa. A decline in the number of intestinal goblet cells and in mucin 2 gene expression was observed in the mice belonging to the BPA group. The results of immunohistochemistry revealed that the expression of tight junction proteins (ZO-1, occludin, and claudin-1) in colonic epithelium of BPA mice decreased significantly, and their gene abundance was also inhibited. Moreover, dietary BPA uptake was also found to have significantly reduced colonic microbial diversity and altered microbial structural composition. The functional profiles of colonic bacterial community exhibited adverse effects of dietary BPA intake on the endocrine and digestive systems, as well as the transport and catabolism functions. Collectively, our study highlighted that dietary BPA increased the colonic permeability, and this effect was closely related to the disruption of intestinal chemistry and physical and biological barrier functions.