Science of the Total Environment最新文献

Changes in winter precipitation accompanying emerging climate trends lead to a major carbon-climate feedback from Arctic tundra. However, the mechanisms driving the direction, magnitude, and form (CO₂ and CH₄) of C fluxes and derived climate forcing (i.e. GWP, global warming potential) from Arctic tundra under future precipitation scenarios remain unresolved. Here, we investigated the impacts of 18 years of shallow (SS, -15-30 %) and deeper (IS, +20-45 %; DS, +70-100 %) snow depth on ecosystem C fluxes and GWP in moist acidic tundra over the growing season. The response of Arctic tundra C fluxes to snow accumulation was markedly non-linear. Both shallow- and deeper- winter snow decreased Arctic tundra CO₂ emissions relative to ambient (AS), ultimately reducing ecosystem C losses over the growing season. Gross primary productivity (GPP) increased with moderate increases in snow depth and decreased with further snow accumulation closely following transitions in shrub abundance. Photosynthetic uptake, however, was tightly regulated by canopy structure and plant respiration (R_aut) to GPP ratio was highly conserved despite substantial transformations of plant community across snow treatments revealing a prominent role of heterotrophic respiration (R_het) in driving net ecosystem exchange. Consistently, ecosystem C gains responded to constraints on R_het by temperature limitation within colder soils at SS, and by snow- and thaw-induced increases in soil-water content (SWC) that promoted anaerobic decomposition and dampened the temperature sensitivity of R_het at IS and DS. Greater CH₄ emissions from wetter soils, however, increased the global warming potential (GWP) of Arctic tundra emissions at IS and DS despite decreases in C losses. Overall, our findings indicate the potential of Arctic tussock tundra to reduce C losses over the growing season but also to significantly contribute to the ecosystem GWP under emerging trends in winter precipitation.

Nowadays, marine pollution is a global problem which finds in microplastics (MPs) and emerging pollutants, such as perfluoroalkyl substances (PFASs), two of the main culprits. Sea cucumbers are a group of marine benthic invertebrates that show ecological, economic and social relevance. As deposit/suspension feeders, sea cucumbers show high susceptibility to bioaccumulate marine pollutants, including PFASs and MPs. In this study, we describe the presence and the effects of MP and PFAS accumulation on gastrointestinal tract (GIT) and coelomic fluid of sea cucumber (Holothuria tubulosa) specimens through the assessment of oxidative stress biomarkers. The MP abundance in the GIT ranged from 3 to 20 particles animal^-1, while the extracted MPs from the coelomic fluid ranged from 0 to 7 particles animal^-1, thus confirming a probable transfer through the respiratory tree. The MPs were identified by FT-IR and Raman analyses, and the polymer types were mainly polyethylene (PE) and polypropylene (PP). The concentrations of nineteen perfluoroalkyl sulfonic acids (PFSAs) were measured in the body wall of sea cucumbers. We found up to seven out of the nineteen PFASs. The Σ₁₉PFAS were in the range 0.083-0.620 μg kg^-1 and the maximum concentrations of individual PFASs in all the samples varied from 0.010 (PFHxA, PFHpA) to 0.390 (PFBS). Pearson coefficients showed a positive correlation among MPs and most of the oxidative stress parameters (i.e. catalase, glutathione S transferase, malondialdehyde and DNA damage) suggesting, however, a potential tissue-related response. This study thus revealed that MPs, and partially PFASs, induce oxidative imbalance in H. tubulosa, and pointed up the importance of different tissues in mediating dose/time-related responses to oxidative stress. Sea cucumbers prove to be very promising model organisms for ecotoxicological investigation.

Large passenger ships are characterised as enclosed and crowded indoor spaces with frequent interactions between travellers, providing conditions that facilitate disease transmission. This study aims to provide an indoor ship CO₂ dataset for inferring thermal comfort, ventilation and infectious disease transmission risk evaluation. Indoor air quality (IAQ) monitoring was conducted in nine environments (three cabins, buffet, gym, bar, restaurant, pub and theatre), on board a cruise ship voyaging across the UK and EU, with the study conducted in the framework of the EU HEALTHY SAILING project. CO₂ concentrations, temperature and relative humidity (RH) were simultaneously monitored to investigate thermal characteristics and effectiveness of ventilation performance. Results show a slightly higher RH of 68.2 ± 5.3 % aboard compared to ASHRAE and ISO recommended targets, with temperature recorded at 22.3 ± 1.4 °C. Generally, good IAQ (<1000 ppm) was measured with CO₂ mainly varying between 400 and 1200 ppm. The estimated air change rates (ACH) and ventilation rates (VR) implied sufficient ventilation was provided in most locations, and the theatre (VR: 86 L s^-1 person^-1) and cabins (VR: >20 L s^-1 person^-1) were highly over-ventilated. Dining areas including the pub and restaurant recorded high CO₂ concentrations (>2000 ppm) potentially due to higher footfall (0.6 person m^-2 and 0.4 person m^-2) and limited ACH (2.3 h^-1 and 0.8 h^-1), indicating a potential risk of infection; these areas should be prioritised for improvement. The IAQ and probability of infection indicate there is an opportunity for energy saving by lowering hotel load for the theatre and cabins and achieving the minimum acceptable VR (10 L s^-1 person^-1) for occupants' comfort and disease control. Our study produced a first-time dataset from a sailing cruise ship's ventilated areas and provided evidence that can inform guidelines about the optimisation of ventilation operations in large passenger ships, contributing to respiratory health, infection control and energy efficiency aboard.

In Santiago, Chile, 315,000 liquid crystal display (LCD) monitors are discarded annually. Of this amount, the formal sector of refurbishment and recycling manages only 5 %, creating the conditions for the emergence of informal management systems. This study provides the first comprehensive environmental and circularity assessment of monitor treatment across multiple impact categories, identifying trade-offs associated with formal and informal operations. For this, a life cycle assessment approach is utilised at both the product-level and the municipal management systems level, addressing the processes from the collection of the monitor to its end-of-life. At the product-level, two formal and two informal routes for managing an LCD monitor were evaluated. The results reveal that formal treatment companies have the best environmental performance in all the midpoint categories of ReCiPe, achieving benefits 42,000 times greater than formal disposal for marine eutrophication, and 25 % better than informal flea market traders across all categories. The analysis of management processes attributes most environmental benefits to refurbishment, representing between 76 % and 99 % of the magnitude of the assessed environmental impacts. A sensitivity analysis shows that the environmental performance of an informal trader surpasses that of a formal treatment company when both offer the same expected lifespan for a refurbished monitor and maintain their respective refurbishment rates offered. The municipal-level analysis was carried out through the evaluation of three scenarios. The results indicate that the scenario in which the informal sector cooperates with the formal sector and exclusively dedicates to collecting monitors exhibits superior environmental performance, averaging environmental benefits that are ten times greater than the current scenario and achieving valorisation rates of 22 %, the highest among the evaluated scenarios. The results of this research contribute to the discussion on formalisation and the promotion of the circular economy in the Global South.

The in-situ electrochemical production of hydrogen peroxide (H₂O₂) offers a promising approach for ballast water treatment. However, further advancements are required to develop electrocatalysts capable of achieving efficient H₂O₂ generation in seawater environments. Herein, we synthesized two-dimensional lamellated porous carbon nanosheets enriched with oxygen functional groups, which exhibited exceptional performance in H₂O₂ electrosynthesis. The carbon nanosheet electrocatalysts demonstrated high selectivity for H₂O₂ production, reaching 90 % at 0.33 V vs. RHE under neutral conditions. Maximum yields were achieved at 2238 mmol g_cat^-1 h^-1 at -0.5 V in an H-type electrolysis cell and 3681 mmol g_cat^-1 h^-1 at a current density of 150 mA cm^-2 in a flow cell, with Faraday efficiencies exceeding 70 %. Notably, a continuous 9-hour electrosynthesis test produced a high cumulative H₂O₂ concentration of 1.2 wt% at a current density of 100 mA cm^-2, highlighting the stability and scalability of carbon nanosheets. The outstanding performance of carbon nanosheets is attributed to the abundant basal plane C-O-C group, which provide optimal *OOH binding energy and minimal overpotential. Additionally, the in-situ generated H₂O₂ from the electrocatalytic system achieved complete sterilization within 60 min against Escherichia coli and several marine bacterial strains isolated from seawater. Furthermore, treatment of real seawater with H₂O₂ significantly altered the bacterial population abundance at both the phylum and genus levels, highlighting its effectiveness in microbial control. This study presents a high-performance electrocatalytic system for ballast water treatment, offering both scalability and environmental sustainability.

Rice productivity and quality are increasingly at risk in arsenic (As) affected areas, challenge that is expected to worsen under changing climatic conditions. Free-Air Concentration Enrichment experiments revealed that eCO₂, eO₃, and eTemp, whether acting individually or in combination with low and high As irrigation, significantly impact rice yield and grain quality. Elevated CO₂ significantly increased shoot biomass, with minimal impact on root biomass, except under low As irrigation conditions. In contrast, eTemp alone reduced both shoot and root biomass, though the effect was not significant; eO₃ alone had little to no effect. Combined climatic stressors showed slight positive effects on growth. Under low As irrigation, eCO₂ and eO₃ promoted root growth but reduced shoot growth, while eTemp significantly suppressed both. High As irrigation exacerbated yield reductions, with the most severe decline observed under eTemp (66 %), followed by eCO₂ (48 %), eO₃ (36 %), and their combination (35 %). Arsenic irrigation, whether low or high, reduced macro and micronutrient concentrations in rice grains, with calcium being sole exception, remaining stable or even increasing. Sugar metabolites decreased under eCO₂, eO₃, and eTemp, but increased with As irrigation. Interestingly, climatic variables generally reduced grain As levels, high As irrigation combined with eCO₂ exposure resulted in elevated grain As. This poses a dual concern: increased cancer risk due to As but potential benefit for individuals with diabetes, as the higher amylose content contributes to lower glycemic index. However, rice grown under high As irrigation exhibited significant nutritional imbalances, being rich in maltose and amylose but deficient in organic acids, phytosterols, fatty acids, organosilicons, and carboxylic acids. These findings underscore the dual threat of climate change and As contamination to rice productivity and quality. Developing resilient rice varieties with low grain As content is essential to ensure sustainable agricultural production and nutritional security in As affected regions.

Coral reefs are degrading at an accelerating rate owing to climate change. Understanding the heat stress tolerance of corals is vital for their sustainability. However, this tolerance varies substantially geographically, and information regarding coral responses across latitudes is lacking. In this study, we conducted a high temperature (34 °C) stress experiment on Porites lutea from tropical Xisha Islands (XS) and subtropical Daya Bay (DY) in the South China Sea (SCS). We compared physiological levels, antioxidant activities, and transcriptome sequencing to explore heat tolerance mechanisms and adaptive potential. At 34 °C, both XS and DY corals experienced significant bleaching and the physiological/biochemical index decreased, with XS corals exhibiting greater changes than DY corals. Transcriptome analysis revealed that coral hosts respond to heat stress mainly by boosting metabolic activity. The subtle transcriptional responses of zooxanthellae C15 underscored the host's pivotal role in thermal stress responses. DY coral hosts showed lower bleaching, stronger physiological plasticity, and higher temperature tolerance thresholds than XS, indicating superior heat tolerance. This superiority is linked to negative feedback transcriptional regulation strategies, including active environmental stress response and genetic information damage repair. The differences in thermal adaptability between tropical and subtropical P. lutea in the SCS may be attributed to their genetic differences and native habitat environments, suggesting that subtropical P. lutea may have the potential to adapt to future climate change. This study provides novel insights for predicting the fate of corals at different latitudes in terms of global warming and provides instructive guidance for coral reef ecological restoration.

Nowadays, polyethylene terephthalate (PET) bottles are widely used for packaging drinks and food. However, concerns have been raised about the possible migration of harmful chemicals, particularly phthalates, from these containers into their contents. Therefore, this study investigates the effects of sunlight exposure and PET bottle reuse on phthalate migration, focusing on three common phthalates: bis(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and benzyl butyl phthalate (BBP). The study used two experimental designs. First, new PET bottles filled with distilled water were stored in the shade and under direct sunlight for 30 days. Second, PET bottles were reused to store various foods (vinegar, mint extract, salty leaves, pickled cucumber, and lemon juice) at 4 °C and 40 °C for 10, 30, 60, and 90 days. Phthalate concentrations were analyzed using solid phase extraction followed by gas chromatography-mass spectrometry (GC/MS). The results showed that exposure of PET bottles to sunlight significantly increased phthalate migration compared to shaded storage (P < 0.001). When reused, storing PET bottles at 40 °C resulted in significantly higher phthalate release from the bottle walls in all storage periods than at 4 °C (P < 0.001)-at 40 °C, longer storage times resulted in a significant increase in phthalate migration (P < 0.001), while at 4 °C storage time had no significant effect on phthalate levels (P < 0.001). This study shows that sunlight, higher storage temperatures, and longer storage times significantly increase the migration of phthalates from PET bottles into their contents. These results highlight the importance of maintaining appropriate storage conditions and limiting the reuse of PET bottles, particularly at higher temperatures and longer storage times, to minimize potential exposure to phthalates.

Upgrading wastewater treatment plants (WWTPs) is a global practice for achieving increasingly stringent nutrient discharge objectives set by governments to accommodate population growth and reduce surface water pollution. However, associated downstream improvements in nutrient conditions are difficult to determine in nearshore regions of large aquatic ecosystems due to complex biophysical processes. We conducted a nine-year water quality study and analyzed the data using linear mixed models (LMMs) within a Before-After-Control-Impact (BACI) framework to assess effects of an upgrade to the Duffin Creek Water Pollution Control Plant (DCWPCP) on surface water nutrient conditions and proliferation of nuisance benthic algae (Cladophora glomerata) in nearshore Lake Ontario. The DCWPCP upgrade resulted in increased effluent concentrations and loads of nitrite+nitrate (NO₂₊₃) due to enhanced nitrification, while reducing total Kjeldahl nitrogen and ammonia+ammonium (NH₃₊₄). However, total phosphorus (TP) in effluent only changed slightly due to operational constraints during plant upgrade. For nearshore nutrient conditions, our LMM-BACI framework revealed that, after upgrade, NH₃₊₄ decreased at impact site relative to control sites. In contrast, following upgrade, an observed decline in NO₂₊₃ concentrations was less pronounced at impact site compared to control sites, suggesting increased NO₂₊₃ inputs into nearshore surface water from the DCWPCP. We could not detect obvious improvement in nearshore TP concentrations, stoichiometric ratios of total inorganic nitrogen to TP and NO₂₊₃ to TP, or phosphorus tissue content of Cladophora, likely due to the only slight reduction in TP from the DCWPCP. Overall, our findings showed that the DCWPCP upgrade increased NO₂₊₃ inputs, which could have important implications for nutrient management and trade-offs associated with WWTP upgrades that reduce one chemical species at the expense of another. Other researchers may find our LMM-BACI framework useful to detect localized impacts of nutrient inputs in nearshore and coastal areas where multiple physical and climate drivers influence water quality.

Although the concept of bioaccumulation for novel brominated flame retardants (NBFRs) is clear, the process and interfering factors of bioaccumulation are still not fully understood. The present study comprehensively evaluated the occurrence, transfer and interfering factors of NBFRs in a marine food web to provide new thought and perspective for the bioaccumulation of these compounds. The occurrence of 17 NBFRs were determined from 8 water, 8 sediment and 303 organism samples collected from Dalian Bay, China. The trophic magnification factor (TMF), the bioaccumulation factor (BAF) and the biota sediment accumulation factor (BSAF) were calculated in a plankton-mollusk-crustacean-fish based food webs. Results showed that among the 17 target NBFRs, 11 compounds appeared the significant trophic magnification and 2 compounds of decabromodiphenylethane (DBDPE) and octabromotrimethylphenylindane (OBIND) presented the significant trophic dilution. The significant positive correlation was found between the value of BAFs and the trophic level for 15 NBFRs (except DBDPE and OBIND), indicating that the species with high BAFs values were all at high trophic levels. The stable and rapid metabolic rates of DBDPE and OBIND constitute the main reason why they hardly accumulate in high trophic level organisms. The BSAFs of NBFRs in swimming organisms were much higher than that in mollusks and crustaceans, indicating that a large part of NBFRs accumulated from food webs. The significant positive correlation between TMF and BAF was observed in high trophic level organisms, which demonstrates the important role of high trophic level organisms in evaluating the bioaccumulation effect of NBFRs.