Chemical warfare agents (CWA) dumped worldwide in all types of aquatic reservoirs pose a potential environmental hazard. Leakage of CWAs from eroding containers at dumping sites had been observed, and their presence in the tissues of aquatic animals was confirmed. However, the ecological effects of CWA have not yet been studied. In standardized laboratory bioassays, we tested if sublethal concentration of Clark I, an arsenic based CWA, can affect life histories (somatic growth rate, fecundity, size at maturity), population growth rate and stable isotope signatures of a keystone crustacean grazer Daphnia magna. We found that the life histories and fitness of daphnids reared in the presence of Clark I differed from those reared in Clark-free conditions. The effects were observed when Clark I concentrations were no less than 5 μg×L⁻¹. With increasing concentrations of the tested CWA, all of the tested parameters decreased linearly. The finding indicates that even sublethal concentrations of Clark I can affect crustacean populations, which should be taken into account when assessing the environmental risks of this particular CWA. We found intraspecific diversity in susceptibility to Clark I, with some clones being significantly less vulnerable than others. We also found that in the presence of Clark I, the ratio of heavy and light isotopes of nitrogen in the bodies of daphnids was affected – daphnids exhibited δ¹⁵N enrichment with increasing concentrations of this CWA. The isotopic composition of carbon was not affected by the presence of Clark I. The nitrogen isotopic signature may be used as an indicator of stress in zooplankton exposed to the presence of toxic xenobiotics.

An understudied consequence of coastal urbanization on marine environments is sound pollution. While underwater anthropogenic sounds are recognized as a threat to aquatic organisms, little is known about the effects of above-surface coastal sound pollution on adjacent underwater soundscapes and the organisms inhabiting them. Here, the impact of noise from the 2019 Ultra Music Festival® in Miami, FL, USA was assessed at the University of Miami Experimental Hatchery (UMEH) located directly adjacent to the music festival and on underwater sound levels in Bear Cut, a nearby water channel. In addition, stress hormone levels in fish held at UMEH were measured before and during the festival. Air sound levels recorded at UMEH during the Ultra Music Festival did not exceed 72 dBA and 98 dBC. The subsurface sound intensity levels in the low frequency band increased by 2–3 dB re 1 μPa in the adjacent waterway, Bear Cut, and by 7–9 dB re 1 μPa in the fish tanks at UMEH. Gulf toadfish (Opsanus beta) housed in the UMEH tanks experienced a 4–5 fold increase in plasma cortisol, their main stress hormone, during the first night of the Ultra Music Festival compared to two baseline samples taken 3 weeks and 4 days before Ultra. While this study offers preliminary insights into this type of sound pollution, more research is needed to conclude if Ultra caused a stress response in wild organisms and to fully understand the implications of this type of sound pollution.

While commuting, individuals are exposed to high concentrations of urban air pollutants that can lead to adverse health effects. This study aims to assess commuters’ exposure to particulate matter (PM) when travelling by car, bicycle, metro and bus in Lisbon. Mass concentrations of PM₂.₅ and PM₁₀ were higher in the metro. On the other hand, the highest BC and PN₀.₀₁₋₁ average concentrations were found in car and bus mode, respectively. In cars, the outdoor concentrations and the type of ventilation appeared to affect the indoor concentrations. In fact, the use of ventilation led to a decrease of PM₂.₅ and PM₁₀ concentrations and to an increase of BC concentrations. The highest inhaled doses were mostly observed in bicycle journeys, due to the longest travel periods combined with enhanced physical activity and, consequently, highest inhalation rates.

As ZnO nanoparticles have been applied in many fields, their biological risks on human health, of course, are worthy of our attention. Whether ZnO NPs have the risk and how colonic cells respond to the invaded ZnO NPs are still unknown. Herein, we evaluated the biological effects of ZnO NPs on colonic mucosal cells by in vitro and in vivo methods. IMCE cells, with APC mutation but phenotypically normal, demonstrated hyperproliferation through activating the CXCR2/NF-κB/STAT3/ERK and AKT pathways when exposed to ZnO NPs for 24 h. Long-term exposure of ZnO NPs resulted in the malignant transformation of IMCE cells, showing the morphological changes, anchorage-independent cell growth ability. Importantly, IMCE cells exposed to ZnO NPs subcutaneously grew and induced tumorigenesis in nude mice. In conclusion, exposure of ZnO NPs could induce malignant transformation of colonic mucosal cells through the CXCR2/NF-κB/STAT3/ERK and AKT pathways. We suggest that it was necessary to consider using the precautionary principle for gastrointestinal contact nanomaterials.

Jarosite and birnessite secondary minerals play a pivotal role in the mobility, transport and fate of trace elements in the environment, although geochemical interactions of these compounds with extremely toxic thallium (Tl) remain poorly known. In this study, we investigated the sorption behavior of Tl(I) onto synthetic jarosite and birnessite, two minerals commonly found in soils and sediments as well as in mining-impacted areas where harsh conditions are involved. To achieve this, sorption and desorption experiments were carried out under two different acidic conditions and various Tl(I) concentrations to mimic natural scenarios. In addition, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and inductively coupled plasma (ICP) analyses were conducted to determine the performance of both minerals for Tl(I) sequestration. Our results indicate that both phases can effectively remove aqueous Tl by different sorption mechanisms. Jarosite preferentially incorporates Tl(I) into the structure to form Tl(I)-jarosite and eventually the mineral dorallcharite (TlFe₃(SO₄)₂(OH)₆) as increasing amounts of Tl are employed. Birnessite, however, favorably uptakes Tl(I) through an irreversible surface adsorption mechanism, underlining the affinity of Tl for this mineral in the entire concentration range studied (0.5–5 mmol L⁻¹). Lastly, the presence of Tl(I) in conditions where aqueous molar ratio Tl/Mn is ∼0.25 inhibits the formation of birnessite since oxidation of Tl(I) to Tl(III) followed by precipitation of avicennite (Tl₂O₃) take place. Thus, the present research may provide useful insights on the role of both jarosite and birnessite minerals in Tl environmental cycles.

This study presents a comprehensive analysis of organic carbon (OC), elemental carbon (EC), and particularly the light absorption characteristics of EC and water-soluble brown carbon (WS–BrC) in total suspended particles in the Kathmandu Valley from April 2013 to January 2018. The mean OC, EC, and water-soluble organic carbon (WSOC) concentrations were 34.8 ± 27.1, 9.9 ± 5.8, and 17.4 ± 12.5 μg m⁻³, respectively. A clear seasonal variation was observed for all carbonaceous components with higher concentrations occurring during colder months and lower concentrations in the monsoon season. The relatively low OC/EC ratio (3.6 ± 2.0) indicates fossil fuel combustion as the primary source of carbonaceous components. The optical attenuation (ATN) at 632 nm was significantly connected with EC loading (ECS) below 15 μg cm⁻² but ceased as ECS increased, reflecting the increased influence of the shadowing effect. The derived average mass absorption cross-section of EC (MACEC) (7.0 ± 4.2 m² g⁻¹) is comparable to that of freshly emitted EC particles, further attesting that EC was mainly produced from local sources with minimal atmospheric aging processes. Relatively intensive coating with organic aerosols and/or salts (e.g., sulfate, nitrate) was probably the reason for the slightly higher MACEC during the monsoon season, whereas increased biomass burning was a major factor leading to lower MACEC in other seasons. The average MACWS₋BᵣC at 365 nm was 1.4 ± 0.3 m² g⁻¹ with minimal seasonal variations. In contrast to MACEC, biomass burning was the main reason for a higher MACWS₋BᵣC in the non-monsoon season. The relative light absorption contribution of WS-BrC to EC was 9.9% over the 300–700 nm wavelength range, with a slightly higher ratio (13.6%) in the pre-monsoon season. Therefore, both EC and WS-BrC should be considered in the study of optical properties and radiative forcing of carbonaceous aerosols in this region.

Based on the goal of green and effective removal of chromium (Cr(VI)) pollution in water and the idea of treating waste with waste, rice straw (RS) was firstly and successfully used in enhancing the photoreduction of highly toxic Cr(VI) to less toxic Cr(III) by oxalic acid (Ox). Batch experiments (the effect of Ox concentration, initial Cr(VI) concentration, RS dosage and coexisting ions) in Ox + RS + UV photoreduction system were designed to investigate the reaction process. Through studying the effect of initial pH in the solution, the change of pH during the photoreduction process and the free radical scavenging test, the Cr(VI) photoreduction mechanism in Ox + RS + UV system was revealed. The role of RS in Ox + RS + UV system was also deduced by the analysis of FT-IR, XRD, Mott-Schottky and the verification test of the role of –OH and SiO₂ on RS. The results showed that RS could significantly synergize Ox to reduce Cr(VI) under UV, 1 mM Cr(VI) in aqueous solution was completely removed in 60 min by Ox + RS + UV system. The Cr(VI) photoreduction mechanism in Ox + RS + UV system consisted of multiple parts: the chemical reduction by Ox(few part), the photoreduction by Ox(some part), and the synergistic photoreduction by RS with Ox(large part). The synergism of RS in Ox + RS + UV system was mainly attributed to its components of SiO₂ and –OH of cellulose.

In this paper, the acute toxicity of monobutyl phthalate (MBP), the main hydrolysis product of dibutyl phthalate, on adult zebrafish liver antioxidant system was studied. Compared the toxicity effect of MBP and DBP by histopathology and apoptosis experiments, we speculated that the toxic effects of DBP on animals may be caused by its metabolite MBP. The results indicated that the antioxidant Nrf2-Keap1 pathway was insufficient to resist MBP-induced hepatotoxicity and led to an imbalance of membrane ion homeostasis and liver damage. Decreased cell viability, significant tissue lesions and early hepatocyte apoptosis were observed in the zebrafish liver in MBP exposure at high concentration (10 mg/L). The activities of antioxidant enzymes and ATPases in zebrafish liver were inhibited with increased malondialdehyde (MDA) content and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities. Integrated biomarker response (IBR) calculation results indicated that MBP mainly inhibited catalase (CAT) activity. Simultaneously, the expression of antioxidant-related genes (SOD, CAT, GPx, Nrf2, HO-1) was down-regulated, while apoptosis-related genes (p53, bax, cas3) were significantly up-regulated.

Tris (1,3-dichloro-2-propyl) phosphate (TDCPP) is a type halogenated organophosphate flame retardants (OPFRs), which has been identified as contaminants of emerging concern (CECs). The use and production of OPFRs began to increase gradually when brominated flame retardants (BFRs) were banned. Halogenated OPFRs, especially TDCPP have been considered to lead to mutagenicity and carcinogenesis and major concerns have been raised regarding their toxicity. In this study, the toxicity effects and mechanisms of TDCPP were summarized and ecological risk assessment was made regarding its potential impact on freshwater organisms. TDCPP has been widely detected in ecosystems throughout the world, with observed toxicity effects on both humans and freshwater organisms. Inhalation of the dust was found to be the main exposure for humans. TDCPP could be metabolized in the human body, and medium stability was achieved in human body with the main metabolite BDCPP. Aside from mutagenicity and carcinogenesis, TDCPP was also found to have the potential for endocrine disruption and impairing the human reproductive system. Furthermore, this study reviewed the results of previous toxicity experiments, including acute toxicity, growth and development toxicity, neurotoxicity, and hepatotoxicity in freshwater organisms. Risk assessment was made using the safety threshold method by comparing the toxicity data with the exposure data in freshwater. HC₅ (hazardous concentration for 5% of organisms) derived based on traditional endpoints of acute toxicity LC₅₀ (median lethal concentration) or EC₅₀ (concentration for 50% of maximal effect) was 877 μg/L. This value was much higher than the exposure concentration levels in the surface water with EXD₉₀ (exposure data with cumulative probability 90%) of 65.22 ng/L. However, based on the growth and development toxicity data, the derived HC₅ was 33.33 ng/L and the calculated MOS (margin of safety) was below 1. Therefore, the results validated the fact that the ecological risk of TDCPP could not be neglected for its growth and development toxicity.

The effects of dike construction on the geomorphology and sedimentary processes of tidal flats were investigated using high-precision topographic profiling, short cores, and unmanned aviation vehicle (UAV)-assisted photogrammetry to understand their adverse consequences on the benthic ecosystem. Tidal flats at the south of Shinsi Island near one of the two sluice gates of the Saemangeum dike, display prominent morphologic features known as shelly sand ridges or cheniers (sensu Otvos, 2000) that have migrated landward about 5 m in a year. The tidal flats were dominated by erosion from winter to spring and by deposition during the remainder of the year except for the periods of heavy precipitation when tidal drainage channels became larger and deeper by headward erosion. With overall coarser-grained surface sediments, the presence of actively migrating wave-built cheniers are in stark contrast to muddy tidal flats with a monotonous morphology before the completion of the Saemangeum dike in 2006. Southeasterly waves reflected from the dike during winter to spring when north to northwesterly winds prevail account for the wave-induced onshore sediment transport and rapid morphologic changes in the tidal flats despite their location protected from offshore waves. The diversity and biomass of major macrofauna species tend to increase during rapid erosion and decrease during rapid deposition, highlighting the anthropogenic effect of dike-induced physical disturbance on the benthic ecosystem in the otherwise sheltered tidal flats.