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Nutrient changes in the Bohai Sea over the past two decades.

With the growing problem of eutrophication in the Bohai Sea, actions have been taken to reduce nutrient inputs, but it remains to be seen whether nutrient levels and structure have been ameliorated. In this study, the nutrient trends in the Bohai Sea are re-examined based on observations from 2000 to 2019. The results suggest that dissolved inorganic nitrogen (DIN) concentrations and DIN/DIP (dissolved inorganic phosphate) ratios gradually increased from 2000 to 2013 but dramatically decreased from 2013 to 2019. The increase and decrease rates of DIN concentrations decreased with increasing water depth, indicating that DIN concentrations in nearshore waters responded more rapidly to changes in human activities. However, DIP concentrations responded weakly to nutrient inputs, with their trends uncoupled. The DIN/DIP ratios have declined close to and in some seasons even below the canonical Redfield ratio in areas with water depths >20m recently, implying that relative nutrient limitation in these areas may be shifting from relative phosphorus (P) limitation to absence of relative nutrient limitation or relative nitrogen (N) limitation. Atmospheric deposition, wastewater discharge, and riverine input were responsible for 66%, 21%, and 13% of the variance in the decline of DIN concentration, respectively. Several environmental indicators responded positively to the decrease in DIN concentrations and DIN/DIP ratios, with varying degrees of recovery recently. Our study proves the phased success of various nutrient reduction measures taken by the Chinese government to improve the environment of the Bohai Sea over the past decade.

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Enhanced detection of mpox virus in wastewater using a pre-amplification approach: A pilot study informing population-level monitoring of low-titer pathogens.

A recent outbreak of the mpox virus (MPXV) occurred in non-endemic regions of the world beginning in May 2022. Pathogen surveillance systems faced pressure to quickly establish response protocols, offering an opportunity to employ wastewater-based epidemiology (WBE) for population-level monitoring. The pilot study reported herein aimed to: (i) develop a reliable protocol for MPXV DNA detection in wastewater which would reduce false negative reporting, (ii) test this protocol on wastewater from various regions across the United States, and (iii) conduct a state of the science review of the current literature reporting on experimental methods for MPXV detection using WBE. Twenty-four-hour composite samples of untreated municipal wastewater were collected from the states of New Jersey, Georgia, Illinois, Texas, Arizona, and Washington beginning July 3rd, 2022 through October 16th, 2022 (n=60). Samples underwent vacuum filtration, DNA extraction from captured solids, MPXV DNA pre-amplification, and qPCR analysis. Of the 60 samples analyzed, a total of eight (13%) tested positive for MPXV in the states of Washington, Texas, New Jersey, and Illinois. The presence of clade IIb MPXV DNA in these samples was confirmed via Sanger sequencing and integration of pre-amplification prior to qPCR decreased the rate of false negative detections by 87% as compared to qPCR analysis alone. Wastewater-derived detections of MPXV were compared to clinical datasets, with 50% of detections occurring as clinical cases were increasing/peaking and 50% occurring as clinical cases waned. Results from the literature review (n=9 studies) revealed successful strategies for the detection of MPXV DNA in wastewater, however also emphasized a need for further method optimization and standardization. Overall, this work highlights the use of pre-amplification prior to qPCR detection as a means to capture the presence of MPXV DNA in community wastewater and offers guidance for monitoring low-titer pathogens via WBE.

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Rainwater input reduces greenhouse gas emission and arsenic uptake in paddy rice systems.

This work aimed to test the hypothesis that rainwater-borne hydrogen peroxide (H2O2) can affect arsenic uptake by rice plants and emission of greenhouse gases in paddy rice systems. A mesocosm rice plant growth experiment, in conjunction with rainwater monitoring, was conducted to examine the effects of rainwater input on functional groups of soil microorganisms related to transformation of arsenic, carbon and nitrogen as well as various arsenic species in the soil and plant systems. The fluxes of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) were measured during selected rainfall events. The results showed that rainwater-borne H2O2 effectively reacted with Fe2+ present in paddy soil to trigger a Fenton-like reaction to produce •OH. Both H2O2 and •OH inhibited As(V)-reducing microbes but promoted As(III)-oxidizing microbes, leading to a net increase in arsenate-As that is less phytoavailable compared to arsenite-As. This impeded uptake of soil-borne As by the rice plant roots, and consequently reduced the accumulation of As in the rice grains. The input of H2O2 into the soil caused more inhibition to methanogens than to methane-oxidizing microbes, resulting in a reduction in CH4 flux. The microbes mediating the transformation of inorganic nitrogen were also under oxidative stresses upon exposure to the rainwater-derived H2O2. And the limited conversion of NO3- to NO played a crucial role in reducing N2O emission from the paddy soils. The results also indicated that the rainwater-borne H2O2 could significantly affect other biogeochemical processes that shape the wider ecosystems, which is worth further investigations.

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The effects of longitudinal fragmentation on riverine beta diversity are modulated by fragmentation intensity.

The loss of longitudinal connectivity affects river systems globally, being one of the leading causes of the freshwater biodiversity crisis. Barriers alter the dispersal of aquatic organisms and limit the exchange of species between local communities, disrupting metacommunity dynamics. However, the interplay between connectivity losses due to dams and other drivers of metacommunity structure, such as the configuration of the river network, needs to be explored. In this paper, we analyzed the response of fish communities to the network position and the fragmentation induced by dams while controlling for human pressures and environmental gradients. We studied three large European catchments covering a fragmentation gradient: Upper Danube (Austrian section), Ebro (Spain), and Odra/Oder (Poland). We quantified fragmentation through reach-scaled connectivity indices that account for the position of barriers along the dendritic network and the dispersal capacity of the organisms. We used generalized linear models to explain species richness and Local Contributions to Beta Diversity (LCBD) and multilinear regressions on the distance matrix to describe Beta Diversity and its Replacement and Richness Difference components. Results show that species richness was not affected by fragmentation. Network centrality metrics were relevant drivers of beta diversity for catchments with lower fragmentation (Ebro, Odra), and fragmentation indices were strong beta diversity predictors for the catchment with higher fragmentation (Danube). We conclude that in highly fragmented catchments, the effects of network centrality/isolation on biodiversity could be masked by the effects of dam fragmentation. In such catchments, metapopulation and metacommunity dynamics can be strongly altered by barriers, and the restoration of longitudinal connectivity (i.e. the natural centrality/isolation gradient) is urgent to prevent local extinctions.

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Is there a downside to plant ecological services in the city? Influences of particulate matter on the two-spotted spider mite (Tetranychus urticae) foraging on the small-leaved lime in urban conditions.

The aim of this research was to examine how particulate matter (PM) pollution affects the life history of the two-spotted spider mite (TSSM), Tetranychus urticae (Trombidiformes: Tetranychidae), in modelled urban conditions. For this purpose, experimental populations of TSSM were cultured on the foliage of small-leaved lime (Tilia cordata) contaminated with PM at intensities corresponding to differing city zones such as a park, a busy road and an industrial area. The control samples in the study were washed, unpolluted leaves. The spider mite was selected as a model organism due to its cosmopolitan distribution, broad host spectrum, resistance to a variety of pesticides and food-intake mode involving cell-content sucking, while T. cordata is widely planted in cities and has demonstrated a considerable capability for PM capture. Data on the longevity and mortality of particular instars and on female fecundity at different pollution levels were collected and statistically evaluated. Concentrations of PM typical for roads and industrial city zones significantly reduced total female fecundity (avg. 53.9 and 55.9 eggs/female, respectively, vs 79.2 in control), which entailed a slower population increase, while the survival rate of particular developmental instars (P = 0.52) and fertility curves (P = 0.19) remained unchanged. The presence of PM caused physiological effects in the mites, despite the lack of direct consumption of the pollutant by adult and juvenile instars. Considering the incomparable resilience of TSSM to unfavourable environmental factors, it is predicted that the detrimental influence of PM on other representatives of urban arthropods may be even more severe. The results suggest that there is a need for further investigations into the ecological ramifications of air purification provided by urban green spaces.

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Paving the way to the future: Mapping historical patterns and future trends of road material stock in Japan.

Roads are a fundamental component of societal infrastructure, whose decades-long lifespan has far-reaching implications for developmental decisions. The road construction and development have profound impacts on economic growth, social dynamics, and environmental sustainability. Therefore, comprehensive measurement of the current road material stock (MS) and the projection of expected future road scale based on regional socio-economic scenarios that can reflect unique local conditions are necessary. This study examined the historical changes and progression patterns of the road network across Japan from 1965 to 2020 through material flow and material stock analysis. By using the road MS time series, along with explanatory socioeconomic variables, several models including Autoregressive Integrated Moving Average with explanatory variables (ARIMAX), Support Vector Regression (SVR), hybrid ARIMAX-SVR, Multiple Linear Regression (MLR), Artificial Neural Networks (ANN), and Random Forest (RF) were compared. After comparison analysis, ARIMAX and hybrid ARIMAX-SVR models were employed to forecast expected road MS in each prefecture of Japan by 2050 based on national shared socioeconomic pathways (SSP) scenarios. The study found that the total road MS of Japan increased 5.5-fold over 55 years. Aggregate was the dominant material, comprising over 70 % among the four materials of the total road MS. The forecast results for each prefecture were classified into three different patterns. Expected MS in most prefectures still displayed increasing trends in the five scenarios, but the projection of road MS in eight prefectures revealed a notable downward trend across each SSP scenario. For most prefectures, SSP5 displayed the highest expected road MS, followed by SSP1. SSP3 was the scenario with the lowest MS. This approach provided a more thorough understanding of the likely evolution of road MS across different SSP scenarios and could help inform decisions for resource allocation and policy formulation concerning road infrastructure management.

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Do drinking water treatment residuals underperform in the presence of compost in stormwater media filters?

Drinking water treatment residuals (WTR), a waste-derived product, are often recommended to use as an amendment in stormwater biofilters to enhance their capacity to remove phosphate and microbial pollutants. However, their efficacy has been assumed to remain high in the presence of compost, one of the most common amendments used in biofilters. This study tests the validity of that assumption by comparing the removal capacities of WTR-amended biofilters with and without the presence of compost. Our results show that amending sand with WTR increased E. coli removal by at least 1-log, but the addition of compost in the sand-WTR media lowered the removal capacity by 13%. Similarly, the addition of WTR to sand improved phosphate removal to nearly 1177%, but the removal decreased slightly by 8% when adding compost to the media. The results confirmed that dissolved organic carbon (DOC) leached from the compost could compete for adsorption sites for bacteria and phosphate, thereby lowering WTR's adsorption capacity based on the amount of DOC adsorbed on WTR. Collectively, these results indicate that the stormwater treatment industry should avoid mixing compost with WTR to get the maximum benefits of WTR for bacterial removal and improve the performance lifetime of WTR-amended biofilters.

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Historical emission and reduction of VOCs from the petroleum refining industry and their potential for secondary pollution formation in Guangdong, China.

China became the world leader in crude oil processing capacity in 2021. However, petroleum refining generates significant volatile organic compound (VOC) emissions, and the composite source profile, source-specific emission factors, and emission inventories of VOCs in the petroleum refining industry remain poorly understood. In this study, we focused on Guangdong, China's major province for crude oil processing, and systematically evaluated the historical emissions and reduction of VOCs in the petroleum refining industry from 2001 to 2020. We accomplished this by establishing local source-specific emission factors and composite source profiles. Finally, we quantitatively assessed the potential impact of these emissions on ozone and secondary organic aerosol formation. Our results revealed that VOC emissions from the petroleum refining industry in Guangdong followed an increasing-then-decreasing trend from 2001 to 2020, peaking at 37.3 Gg in 2016 and declining to 18.7 Gg in 2020. Storage tanks and wastewater collection and treatment remained the two largest sources, accounting for 41.9 %-53.4 % and 20.6 %-27.5 % of total emissions, respectively. Initially, Guangzhou and Maoming made the most significant contributions, with Huizhou becoming a notable contributor after 2008. Emission reduction efforts for VOCs in Guangdong's petroleum refining industry began showing results in 2017, with an average annual VOC emission reduction of 21.5 Gg from 2017 to 2020 compared to the unabated scenario. Storage tanks, wastewater collection and treatment, and loading operations were the primary sources of emission reduction, with significant contributions from Maoming, Huizhou, and Guangzhou. Alkanes made the largest contribution to VOC emissions, while alkenes/alkynes and aromatics comprised the most significant portions of ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAP). We also estimated VOC emissions and reduction from petroleum refining for China from 2001 to 2020, and measures such as "one enterprise, one policy" and deep control strategies could reduce emissions by at least 103.9 Gg.

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Aerial monitoring of atmospheric particulate matter produced by open-pit mining using low-cost airborne sensors.

Mining is an economic activity that entails the production and displacement of significant amounts of atmospheric particulate matter (PM) during operations involving intense earthcrushing or earthmoving. As high concentrations of PM may have adverse effects on human health, it is necessary to monitor and control the fugitive emissions of this pollutant. This paper presents an innovative methodology for the online monitoring of PM10 concentrations in air using a low-cost sensor (LCS, <300 USD) onboard an unmanned aerial vehicle. After comprehensive calibration, the LCS was horizontally flown over seven different areas of the large Riotinto copper mine (Huelva, Spain) at different heights to study the PM10 distribution at different longitudes and altitudes. The flights covered areas of zero activity, intense mining, drilling, ore loading, waste discharge, open stockpiling, and mineral processing. In the zero-activity area, the resuspension of PM10 was very low, with a weak wind speed (3.6m/s). In the intense-mining area, unhealthy concentrations of PM10 (>51 μgPM10/m3) could be released, and the PM10 can reach surrounding populations through long-distance transport driven by several processes being performed simultaneously. Strong dilution was also observed at high altitudes (> 50m). Mean concentrations were found to be 22-89 μgPM10/m3, with peaks ranging from 86 to 284 μgPM10/m3. This study demonstrates the potential applicability of airborne LCSs in the high-resolution online monitoring of PM in mining, thus supporting environmental managers during decision-making against fugitive emissions in a cost-effective manner.

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