Nowadays, marine ecosystems are under severe threat from the simultaneous presence of multiple stressors, including microplastics (MPs) and polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]pyrene (B[a]P). In addition to their presence in various marine compartments, there are increasing concerns on the potential capacity of MPs to sorb, concentrate and transfer these pollutants in the environment. Although their ecotoxicological impacts are currently evident, few works have studied the combined effects of these contaminants. Therefore, the major purpose of this work was to assess the toxicity of environmental relevant concentrations of MPs (<30 μm) and B[a]P, alone and in mixture, in the seaworm Hediste diversicolor by exploring their accumulation and hazardous biological effects for 3 and 7 days. Environmental MPs were able to increase B[a]P in a time-dependent manner. The obtained results showed that individual treatments, as well as co-exposure to contaminants, caused cytotoxicity and genotoxicity in the cœlomic fluid cells, while oxidative stress effects were observed at tissue and gene levels associated with alteration in neurotransmission. Overall, our findings provide additional clues about MPs as organic pollutant vectors in the marine environment, and contribute to a clearer understanding of their toxicological risk to aquatic invertebrates.

Aquatic natural colloids are closely related to the environmental behavior of pollutants, which may affect their bioavailability in aquatic organisms. This study explored the potential mechanisms of the natural colloids at environmentally relevant concentrations affecting the bioaccumulation process of benzophenone-3 (BP3) in zebrafish (Danio rerio). The results of kinetic model fitting showed that the natural colloids decreased the uptake and loss rate of BP3 by zebrafish but prolonged the time to reach the cumulative equilibrium, eventually resulting in a higher cumulative concentration in zebrafish. According to the tissue concentration at equilibrium and the results of toxicokinetic analysis, the presence of high molecular colloids could enhance the bioaccumulation of freely dissolved BP3 due to its high desorption rate with BP3 in the intestines of fish, increasing the freely dissolved BP3 concentrations to which zebrafish were exposed. Both natural colloids and BP3 could enhance the cell permeability of zebrafish, which allowed colloid-bound BP3 to directly enter the fish and accumulate in its muscle. Besides, although both natural colloids and BP3 could cause the metabolic disorders in adult zebrafish, they affected the physiological and biochemical activities of zebrafish through different pathways. The disturbance of glutathione metabolism in zebrafish induced by natural colloids may be the reason for the diminished ability of zebrafish to clear and transform BP3 in the mixture system. The carrier effect of natural colloids and reduced clearance ability of zebrafish eventually increased the bioaccumulation of BP3 in zebrafish. This study highlights the significance of natural colloids at environmentally relevant concentrations on the biological effects of emerging contaminants in actual waters, however, natural colloids are always ignored in most field investigation of pollutants, which would ultimately lead to an underestimation of the true ecological risk of pollutants.

We present a comprehensive review of the sediment quality triad (SQT) assessment studies in Korea. The bibliographic analysis was applied to evaluate how approaches in sediment assessment have evolved. A meta-analysis was performed, to evaluate potential risks of sedimentary persistent toxic substances (PTSs) reported in Korean coastal waters. Within the framework, we identified and discussed current status and spatiotemporal trends in contamination of both classic and emerging PTSs over the recent decadal period. Out of 26 target regions in Korea, five hotspots (Sihwa, Masan, Ulsan, Taean, and Gwangyang) of concern could be identified. Four of those regions have been designated as Specially-Managed Sea Area under the implementation of Total Pollution Load Management System in Korea, except for Taean coast (oil spill site). Meantime, we could identify three stepwise research phases based on a bibliographic analysis; Phase 1 (1995–2008), Phase 2 (2009–2015), and Phase 3 (2016–2020). It is noteworthy that a technical evolution of the SQT assessment by the phase was featured. It was also evidenced that in-depth studies adopting multiple lines of evidence (LOEs) became prevailed upon approaching Phase 3. In a quantitative manner, the toxicity explanatory power of target PTSs increased by about 10% in Phase 3 compared to the earlier phases. The meta-analysis using ratio-to-mean value method applied for the data set having all three LOEs indicated general improvement of sediment qualities in the hotspots. However, their associations quite varied across regions and years, reflecting a dynamicity in oceanographic settings and/or heterogeneity in toxicological effect or benthic community response. At present, SQT assessment adopting the increased LOEs generally supports better assessment. In conclusion, we suggest that future SQT studies globally should reaffirm the utility of the “multiple LOEs approach”, focusing on the identification and management of causative toxicants that driving negative ecological impacts on marine ecosystems.

Long-term noise exposure is reported to damage cardiovascular system, but the relationship between occupational noise exposure and arterial stiffness (AS) and the underlying mechanism is still unclear. We aimed to investigate the association of occupational noise exposure with arterial stiffness (AS), and further explore the mediation roles of microRNAs (miRNAs). A total of 838 workers were recruited from two companies in Wuhan, Hubei, China. Cumulative occupational noise exposure (CNE) was assessed through noise level of job title and work years in occupational noise. The AS for the participants were evaluated using brachial-ankle pulse wave velocity (baPWV) measured by an oscillometric device. Each 1-unit increase in CNE levels was significantly associated with a 0.002 (95% confidence interval (CI) = 0.001–0.003) unit increase in ln-transformed values of baPWV. In the sex-specific analysis, the association was significant in males (β = 0.002, 95%CI = 0.001–0.003). Meanwhile, the risk of bilateral hearing loss at high frequency was significantly higher in the high-exposed group than non-exposed group (OR = 1.895, 95%CI = 1.024–3.508), and participants with bilateral hearing loss at high frequency had a significantly higher level of ln-transformed baPWV (β = 0.032, 95%CI = 0.003–0.061). Occupational noise exposure and AS were both negatively associated with plasma miR-92a-3p and miR-21–5p, and the two miRNAs mediated 15.0% and 16.8% of the association of occupational noise with AS (P < 0.05). Our findings suggest that occupational noise exposure is positively associated with AS, and plasma miR-92a-3p and miR-21–5p may partly mediate such association.

This study aims at exploring size distribution, meteorological influence and uncertainty for source-specific risks of atmospheric particulate matter (PM), which can improve risk-mitigation strategies for health protection. Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) in PM₂.₅ and PM₁₀ were detected in a Chinese megacity during 2011–2021. A new method named as PMFBMR, which combines the Positive Matrix Factorization, Bootstrapping, Mote Carlo and Risk assessment model, was developed to estimate uncertainty of source-specific risks. It was found that PAH risks concentrated in fine PM, while HMs showed high risks in both fine and coarse PMs. For PM₂.₅, HQ (non-cancer risk hazard quotient) of gasoline combustion (GC), diesel and heavy oil combustion (DC), coal combustion (CC), industrial source (IS), resuspended dust (RD) and secondary and transport PM (ST) were 0.6, 1.4, 0.9, 1.6, 0.3, and 0.3. ILCR (lifetime cancer risk) of sources were IS (9.2E-05) > DC (2.6E-05) = CC (2.6E-05) > RD (2.2E-05) > GC (1.7E-05) > ST (6.4E-06). PM₂.₅ from GC, DC, CC and IS caused higher risks than coarse PM, while coarse PM from RD caused higher risks. Source-specific risks were influenced not only by emissions, but also by meteorological condition and dominant toxic components. Risks of GC and DC were usually high during stable weather. Some high risks of CC, IS and RD occurred at strong WS due to transport or wind-blown resuspension. GC and DC risks (influenced by both PAHs and HMs) showed strong relationship with T, while IS and RD risks (dominated by HMs) showed weak link with meteorological conditions. For uncertainty of source-specific risks, HQ and ILCR were sensitive for different variables, because they were dominated by components with different uncertainties. When using source-specific risks for risk-mitigation strategies, the focused toxic components, used toxic values, PM sizes and uncertainty are necessary to be considered.

The removal of organic pollutants presents a major challenge for drinking water treatment plants. The chemical oxygen demand (COD) is essentially the measure of oxidizable organic matter in source waters. In this study, we report that COD can efficiently be decreased by adding Fe(II)/Fe(III) and sulfite ion to the source water while purging it with air. In this process, oxygen is activated to oxidize the main constituents of COD, i.e. organic substrates, via the generation of reactive inorganic oxysulfur radical ions. In the end, the total amount of sulfur(IV) is converted to the non-toxic sulfate ion. It has been explored how the COD removal efficiency depends on the concentration of S(IV), the total concentration of iron species, the concentration ratio of Fe(II) and Fe(III), the purging rate and the contact time by using source water from a specific location (Királyhegyes, Hungary). The process has been optimized by applying the Response Surface Methodology (RSM). Under optimum conditions, the predicted and experimentally found COD removal efficiencies are in excellent agreement: 85.4% and 87.5%, respectively. The robustness of the process was tested by varying the optimum values of the parameters by ± 20%. It was demonstrated that the method is universally applicable because a remarkable decrease was achieved in COD, 62.0–88.5%, with source waters of various compositions acquired from 9 wells at other locations using the same conditions as in the case of Királyhegyes.

Ultrafine particles (UFP), harmful to human health, are emitted at high levels from motorized traffic. Bicycle commuting is increasingly encouraged to reduce traffic emissions and increase physical activity, but higher breathing rates increase inhaled UFP concentrations while in traffic. We assessed exposure to UFP while cycling along a fixed 8.5 km inner-city route in Copenhagen, on weekdays over six weeks (from September to October 2020), during morning and afternoon rush-hour, as well as morning non-rush-hour, traffic time periods starting from 07:45, 15:45, and 09:45 h, respectively. Continuous measurements were made (each second) of particle number concentration (PNC) and location. PNC levels were summarized and compared across time periods. We used generalized additive models to adjust for meteorological factors, weekdays and trends. A total of 61 laps were completed, during 28 days (∼20 per time period). Overall mean PNC was 18,149 pt/cm³ (range 256–999,560 pt/cm³) with no significant difference between morning rush-hour (18003 pt/cm³), afternoon rush-hour (17560 pt/cm³) and late morning commute (17560 pt/cm³) [p = 0.85]. There was substantial spatial variation of UFP exposure along the route with highest PNC levels measured at traffic intersections (∼38,000-42000 pt/cm³), multiple lane roads (∼38,000-40000 pt/cm³) and construction sites (∼44,000-51000 pt/cm³), while lowest levels were measured at smaller streets, areas with open built environment (∼12,000 pt/cm³), as well as at a bus-only zone (∼15,000 pt/cm³). UFP exposure in inner-city Copenhagen did not differ substantially when bicycling in either rush-hour or non-rush-hour, or morning or afternoon, traffic time periods. UFP exposure varied substantially spatially, with highest concentrations around intersections, multiple lane roads, and construction sites. This suggests that exposure to UFP is not necessarily reduced by avoiding rush-hours, but by avoiding sources of pollution along the bicycling route.

Arbuscular mycorrhizal fungi (AMF) are easily influenced by increasing atmospheric CO₂ concentration and heavy metals including cadmium (Cd), which can regulate antioxidant enzyme in host plants. Although the effect of AMF under individual conditions such as elevated CO₂ (ECO₂) and Cd on antioxidant enzyme in host plants has been reported widely, the effect of AMF under ECO₂ + Cd receives little attention. In this study, a pot experiment was conducted to study the effect of AMF community in roots on superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities in leaves of 135-d Robinia pseudoacacia L. seedlings under ECO₂ + Cd. The activities of SOD and CAT increased and POD activity and the richness and diversity of AMF community decreased under ECO₂ + Cd relative to Cd alone. The richness and diversity of AMF were negatively related to Cd content in roots and leaves. The richness and OTUs of AMF community positively and AMF gene abundance negatively affected POD activity under the combined treatments. Superoxide dismutase and POD activities were negatively and positively related to Archaeospora and Scutellospora, respectively, under ECO₂ + Cd. Cadmium in roots and leaves was negatively and significantly related to Glomus, Scutellospora, and Claroideoglomus abundance under ECO₂ + Cd. Overall, AMF diversity and Archaeospora and Scutellospora in roots significantly influenced SOD, POD, and CAT activities. The response of AM symbiosis to ECO₂ might regulate antioxidant capacity in host plants upon Cd exposure. Glomus, Scutellospora, and Claroideoglomus might be applied to phytoremediation of Cd-contaminated soils.

Mine waste classification preceding mining constitutes a proactive solution to classify and segregate mine waste into geo-environmental domains based upon the magnitude of their environmental risks. However, upstream classification requires multi-disciplinary and integrated approaches. This study integrates geological modeling and kinetic modeling to inform upstream mine waste classification based on the pH generated from the main acid-generating and acid-neutralizing reactions once the mine solid waste is stored in oxidizing conditions. Geological models were used to depict the ante-mining spatial distribution of the main reactive minerals: pyrite, albite and calcite. Subsequently, the corresponding block models were created. The dimension of the elementary voxels for each block model was set at 40х40х40 m for this study. The kinetic modeling approach was performed using PHREEQC and VS2DRTI to consider unsaturated conditions. The kinetic modeling simulated a 1D column for each voxel. The column simulates the excavated state of the hosting rock involving kinetic reactions and unsaturated flow under highly oxidizing conditions. Subsequently, the resulting pH for different intervals of time was assigned to its respective voxel. The outcome consists of a spatio-temporal visualization of the pH defining ante-mining geo-environmental domains, thereby providing the opportunity for formulating proactive management measures regarding the hazardous geo-environmental domains.

Due to the large-scale outbreak of Corona Virus Disease (2019), amounts of disinfecting agents was regularly used in public environments and their potential toxicity towards organisms needed to be appreciated. Thus, one mostly used cationic disinfectant, benzalkonium chlorides (BAC(C12)), was selected to assess its potential toxicity one common cyanobacteria Microcystis aeruginosa (M. aeruginosa) in this study. The aims were to explore the toxic effect and mechanism of BAC (C12) on M. aeruginosa growth within 96 h via morphological, physiological, and the relative and absolute quantification (iTRAQ)-based quantitative proteomics variations. The results found that BAC(C12) significantly inhibited cell density of M. aeruginosa at concentrations from 1 mg/L to 10 mg/L, and the 96-h EC₅₀ value was identified to be 3.61 mg/L. Under EC₅₀ concentration, BAC(C12) depressed the photosynthesis activities of M. aeruginosa exhibited by 36% decline of the maximum quantum yield for primary photochemistry (Fv/Fm) value and denaturation of photosynthetic organelle, caused oxidative stress response displayed by the increase of three indexes including superoxide dismutase (SOD), malondialdehyde (MDA), and the intracellular reactive oxygen species (ROS), and destroyed the integrity of cell membranes demonstrated by TEM images and the increase of ex-cellular substances. Then, the iTRAQ-based proteomic analysis demonstrated that BAC(C12) depressed photosynthesis activities through inhibiting the expressions of photosynthetic protein and photosynthetic electron transport related proteins. The suppression of electron transport also led to the increase of superoxide radicals and then posed oxidative stress on cell. Meantime, the 63.63% ascent of extracellular microcystin production of M. aeruginosa was observed, attributing to the high expression of microcystin synthesis proteins and the damage of cell membrane. In sum, BAC(C12) exposure inhibited the growth of M. aeruginosa mainly by depressing photosynthesis, inducing oxidative stress, and breaking the cell membrane. And, it enhanced the release of microcystin from the cyanobacterial cells via up-regulating the microcystin synthesis proteins and inducing the membrane damage, which could enlarge its toxicity to aquatic species.