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Sensitivity and specificity of macroinvertebrate responses to gradients of multiple agricultural stressors Full text
2021
Brooks, Andrew J. | Bray, Jonathan | Nichols, Susan J. | Shenton, Mark | Kaserzon, Sarit | Nally, Ralph Mac | Kefford, Ben J.
Environmental degradation of rivers in agricultural landscapes is typically caused by multiple co-occurring stressors, but how interactions among stressors affect freshwater ecosystems is poorly understood. Therefore, we investigated the sensitivity and specificity of several measures of benthic macroinvertebrate community response to the individual and combined effects of the pesticide sulfoxaflor (SFX), increased sand sedimentation and elevated nutrients using outdoor recirculating mesocosms. Among the single stressor treatments, nutrients had no observable impact and sand only affected one community response measure compared to controls. High SFX levels had the largest effects on benthic macroinvertebrate communities, negatively affecting six of seven macroinvertebrate response measures. Sulfoxaflor had similar adverse effects on biota when in combination with sand and nutrients in the multi-stressor treatment, suggesting that generally SFX has overwhelming and pervasive effects irrespective of the presence of the other stressors. In contrast to SFX, elevated nutrients had no detectable effect on macroinvertebrate communities, likely as a consequence of nutrients being rapidly taken up by bacteria rather than by benthic algae. Elevated sand sedimentation increased the negative effects of SFX on sediment sensitive taxa, but generally had limited biological effects. This was despite the levels of sedimentation in our treatments being at concentrations that have caused large impacts in other studies. This research points to direct and rapid toxic effects of SFX on stream macroinvertebrates, contrasting with effects of the other stressors. This study emphasises that pesticide effects could be misattributed to other common freshwater stressors, potentially focussing restoration actions on a stressor of lesser importance.
Show more [+] Less [-]Seasonal variations in atrazine degradation in a typical semienclosed bay of the northwest Pacific ocean Full text
2021
Wang, Zihan | Ouyang, Wei | Tysklind, Mats | Lin, Chunye | Wang, Baodong
Pesticides are widely used to alleviate pest pressure in agricultural systems, and atrazine is a typical diffuse pollutant and serves a sensitivity index for environmental characteristics. Based on the physicochemical properties of parent substances, degradation products of pesticides may pose a greater threat to aquatic ecosystems than pesticides. Atrazine and three primary degradation products (deethylatrazine (DEA), deisopropylatrazine (DIA) and didealkylatrazine (DDA)) were investigated in a semienclosed bay of the western Pacific Ocean. Seasonal surface water and suspended particulate sediment (SPS) samples were collected from the estuary and bay in January, April, and August 2019. The level of pesticide contamination was lower in the bay than in the estuary, and the pesticide concentration in the dissolved phase was higher than that in the adsorbed phase. The average concentrations of atrazine and the three degradation products in the three seasons ranged from 2.42 to 328.46 ng/L in water and from 0.07 to 12.75 ng/L in SPS. The proportion of atrazine among the four detected pollutants decreased from 0.7 to 0.1 in surface water and from 0.3 to 0.1 in SPS over the seasons. As the main degradation products, the concentration proportions of DDA and DEA reached as high as 0.6 in August. The ratio of DEA to atrazine (DEA/ATR) increased from January to August, which indicated the progressive degradation process in the bay. Single-factor analysis of variance and principal component analysis indicated that atrazine degradation was sensitive to temperature, dissolved oxygen, and salinity. These three factors accounted for almost 70% of the seasonal variance in atrazine without a quantification assessment of photolysis or bacteria. The spatial distributions of DEA in the three seasons demonstrated that wind and currents also played important roles in pollutant redistribution. The seasonal temporal and spatial correlations between water and SPS demonstrated the degradation patterns of atrazine in marine conditions, supporting the need for future detailed toxicity studies.
Show more [+] Less [-]Environmental changes affecting physiological responses and growth of hybrid grouper – The interactive impact of low pH and temperature Full text
2021
Thalib, Yusnita A | Razali, Ros Suhaida | Mohamad, Suhaini | Zainuddin, Rabi’atul ‘Adawiyyah | Rahmah, Sharifah | Ghaffar, Mazlan Abd | Nhan, Hua Thai | Liew, Hon Jung
Rising of temperature in conjunction with acidification due to the anthropogenic climates has tremendously affected all aquatic life. Small changes in the surrounding environment could lead to physiological constraint in the individual. Therefore, this study was designed to investigate the effects of warm water temperature (32 °C) and low pH (pH 6) on physiological responses and growth of hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) juveniles for 25 days. Growth performance was significantly affected under warm water temperature and low-pH conditions. Surprisingly, the positive effect on growth was observed under the interactive effects of warm water and low pH exposure. Hybrid grouper exposed to the interactive stressor of warm temperature and low pH exhibited higher living cost, where HSI content was greatly depleted to about 2.3-folds than in normal circumstances. Overall, challenge to warm temperature and low pH induced protein mobilization as an energy source followed by glycogen and lipid to support basal metabolic needs.
Show more [+] Less [-]Effects of endocrine disrupting chemicals in host health: Three-way interactions between environmental exposure, host phenotypic responses, and gut microbiota Full text
2021
Li, Na | Li, Jinhua | Zhang, Qingqing | Gao, Shenshen | Quan, Xu | Liu, Ping | Xu, Chundi
Endocrine disrupting chemicals (EDCs) have gradually become a global health hazard in recent decades. Gut microbiota (GM) provides a crucial interface between the environment and the human body. A triad relationship may exist between EDCs exposure, host phenotypic background, and GM effects. In this review, we attempted to parse out the contribution of GM on the alteration of host phenotypic responses induced by EDCs, suggesting that GM intervention may be used as a therapeutic strategy to limit the expansion of pathogen. These studies can increase the understanding of pathogenic mechanisms, and help to identify the modifiable environmental factors and microbiota characteristics in people with underlying disease susceptibility for prevention and remediation.
Show more [+] Less [-]Comprehensive chemical characterization of indoor dust by target, suspect screening and nontarget analysis using LC-HRMS and GC-HRMS Full text
2021
Dubocq, Florian | Kärrman, Anna | Gustavsson, Jakob | Wang, Thanh
Since humans spend more than 90% of their time in indoor environments, indoor exposure can be an important non-dietary pathway to hazardous organic contaminants. It is thus important to characterize the chemical composition of indoor dust to assess the total contaminant exposure and estimate human health risks. The aim of this investigation was to perform a comprehensive chemical characterization of indoor dust. First, the robustness of an adopted extraction method using ultrasonication was evaluated for 85 target compounds. Thereafter, a workflow combining target analysis, suspect screening analysis (SSA) and nontarget analysis (NTA) was applied to dust samples from different indoor environments. Chemical analysis was performed using both gas chromatography and liquid chromatography coupled with high resolution mass spectrometry. Although suppressing matrix effects were prominent, target analysis enabled the quantification of organophosphate/brominated flame retardants (OPFRs/BFRs), liquid crystal monomers (LCMs), toluene diisocyanate, bisphenols, pesticides and tributyl citrate. The SSA confirmed the presence of OPFRs but also enabled the detection of polyethylene glycols (PEGs) and phthalates/parabens. The combination of hierarchical cluster analysis and scaled mass defect plots in the NTA workflow confirmed the presence of the above mentioned compounds, as well as detect other contaminants such as tetrabromobisphenol A, triclocarban, diclofenac and 3,5,6-trichloro-2-pyridinol, which were further confirmed using pure standards.
Show more [+] Less [-]Do improved biomass cookstove interventions improve indoor air quality and blood pressure? A systematic review and meta-analysis Full text
2021
Kumar, Nitya | Phillip, Eunice | Cooper, Helen | Davis, Megan | Langevin, Jessica | Clifford, Mike | Stanistreet, Debbi
This systematic review and meta-analysis evaluates the most recent evidence to examine whether use of improved biomass cookstoves in households in low-middle income countries results in reduction in mean concentrations of carbon monoxide (CO) and particulate matter of size 2.5 μm (PM₂.₅) in the cooking area, as well as reduction in mean systolic (SBP) and diastolic blood pressure (DBP) of adults using the cookstoves when compared to adults who use traditional three stone fire or traditional biomass cookstoves.We searched databases of scientific and grey literature. We included studies if published between January 2012 and June 2021, reported impact of ICS interventions in non-pregnant adults in low/middle-income countries, and reported post-intervention results along with baseline of traditional cookstoves. Outcomes included 24- or 48-h averages of kitchen area PM₂.₅, CO, mean SBP and DBP. Meta-analyses estimated weighted mean differences between baseline and post-intervention values for all outcome measures.Eleven studies were included; ten contributed estimates for HAP and four for BP. Interventions lead to significant reductions in PM₂.₅ (−0.73 mg/m³, 95% CI: −1.33, −0.13), CO (−8.37 ppm, 95%CI: −13.20, −3.54) and SBP (−2.82 mmHg, 95% CI: −5.53, −0.11); and a non-significant reduction in DBP (−0.80 mmHg, 95%CI: −2.33, 0.73), when compared to baseline of traditional cookstoves. Except for DBP, greatest reductions in all outcomes came from standard combustion ICS with a chimney, compared to ICS without a chimney and advanced combustion ICS.Among the reviewed biomass stove types, ICS with a chimney feature resulted in greatest reductions in HAP and BP.
Show more [+] Less [-]Enhancement of the heterogeneous adsorption and incorporation of uraniumVI caused by the intercalation of β-cyclodextrin into the green rust Full text
2021
Huang, Tao | Su, Zhiyu | Dai, Yuxing | Zhou, Lulu
The influence of intercalated anions on the structure and composition of green rusts supplies a theoretical possibility for the investigation of the structural modification of Feᴵᴵ/Feᴵᴵᴵ (oxyhydr)oxide materials. β-Cyclodextrin was intercalated into the mixed-valent iron-based hydroxide layers to synthesize new green rust materials (β-CD GRs), pursuing high-capacity uraniumⱽᴵ (Uⱽᴵ) sorption. The molar ratios of Feᴵᴵ to Feᴵᴵᴵ and the molar ratios of β-CD GR to Feᴵᴵ + Feᴵᴵᴵ had a significant effect on the synthesis of β-CD GRs. The synthesis process was further optimized by the quadric predictor and desirability function in a central composite design in combination. Both strong acidity and alkalinity were harmful to the adsorption of β-CD GRs towards Uⱽᴵ. The pseudo-first-order kinetic model and Langmuir isotherm model were appropriate in fitting the whole adsorption process. The maximum monolayer adsorption capacity of β-CD GRs was 2548.61 mg/g. The presence of mimic groundwater constituents explicitly deteriorated the interaction between β-CD GR and Uⱽᴵ species. Nanoscale nodules and particles were formed on the β-CD GR after the adsorption experiments. The peaks at 1159 and 609 cm⁻¹ vanished with the band at 1103 cm⁻¹ being left-shifted to 1117 cm⁻¹ in the FTIR spectra of β-CD GR during the heterogeneous process. The intercalation of β-CD brought obvious enhancement of Uⱽᴵ species sorption to the GR material, which was combinedly driven by several reaction pathways and different from the unmodified GRs.
Show more [+] Less [-]Selective production of singlet oxygen from zinc-etching hierarchically porous biochar for sulfamethoxazole degradation Full text
2021
Sun, Chen | Chen, Tong | Huang, Qunxing | Duan, Xiaoguang | Zhan, Mingxiu | Ji, Longjie | Li, Xiaodong | Yan, Jianhua
Porous carbons are appealing low-cost and metal-free catalysts in persulfate-based advanced oxidation processes. In this study, a family of porous biochar catalysts (ZnBC) with different porous structures and surface functionalities are synthesized using a chemical activation agent (ZnCl₂). The functional biochars are used to activate persulfate for sulfamethoxazole (SMX) degradation. ZnBC-3 with the highest content of ketonic group (CO, 1.25 at%) exhibits the best oxidation efficiency, attaining a rate constant (kₒbₛ) of 0.025 min⁻¹. The correlation coefficient of the density of CO to kₒbₛ (R² = 0.992) is much higher than the linearity of the organic adsorption capacity to kₒbₛ (R² = 0.694), implying that CO is the intrinsic active site for persulfate activation. Moreover, the volume of mesopore (R² = 0.987), and Zeta potential (R² = 0.976) are also positive factors in PS adsorption and catalysis. In the mechanistic study, we identified that singlet oxygen is the primary reactive oxygen species. It can attack the –NH₂ group aligned to the benzene ring to form dimer products which could be adsorbed on the biochar surface to reach complete removal of the SMX. The optimal pH range is 4–6 which will minimize the electrostatic repulsion between ZnBCs and the reactants. The SMX degradation in ZnBC/PS system was immune to inorganic anions but would compete with organic impurities in the real wastewater. Finally, the biochar catalysts are filled in hydrogel beads and packed in a flow-through packed-bed column. The continuous system yields a high removal efficiency of over 86% for 8 h without decline, this work provided a simple biochar-based persulfate catalyst for complete antibiotics removal in salty conditions.
Show more [+] Less [-]A novel modified Fe–Mn binary oxide graphite felt (FMBO-GF) cathode in a neutral electro-Fenton system for ciprofloxacin degradation Full text
2021
Huang, Anqi | Zhi, Dan | Zhou, Yaoyu
A graphite felt (GF) cathode was firstly modified by Fe–Mn binary oxide (FMBO), active carbon (AC), carbon black (CB), and polytetrafluoroethylene (PTFE), which exhibits satisfactory ciprofloxacin (CIP) removal efficiency at neutral pH value in electro-Fenton (EF) system. Morphological data showed that modified cathodes have larger surface area and volume pore as well as more active sites. And electrochemical properties have proved stronger current response after modification. In compassion to the unmodified GF, the FMBO/AC/CB modified GF (FMBO-GF) has wider pH range and higher CIP removal efficiency due to its unique nanoparticles structure. The CIP removal efficiency achieved 95.40% in 30 min, and the removal efficiency of total organic carbon (TOC) achieved 93.77% in 2 h when conditions were optimal (25 mg/L initial CIP concentration, 2 mA/cm² current density, FMBO/AC: CB: PTFE of 1:1:5, and 7 initial pH value) in this study. The results of great degradation and mineralization of CIP in this study indicate that the FMBO-GF cathode has huge potential on antibiotics removals in neutral environment.
Show more [+] Less [-]A proposal for producing calculated noise mapping defining the sound power levels of roads by street stratification Full text
2021
Barrigón Morillas, Juan Miguel | Montes González, David | Gómez Escobar, Valentín | Rey Gozalo, Guillermo | Vílchez-Gómez, Rosendo
The European Noise Directive proposes using strategic noise maps as tools to assess populations affected by environmental noise. It recommends using computational methods instead of in situ measurements when possible. A sound source’s emission power is an important factor in the calculation of noise indicators. For traffic noise, this parameter is usually defined based on vehicle flow considering an emission spectrum that depends on the type of vehicle and its speed. This study analysed the possibility of using the categorisation method to propose an alternative method of defining a sound source’s emission power to develop noise maps. This was accomplished using previously published values of the emission power per unit length. Another method is also proposed that estimates traffic flows. To verify their estimation capacity, the results of both methods were compared with the values obtained from in situ measurements. The results demonstrated similar uncertainties in both methods and were in the range of expected average uncertainties compared to the results obtained by calculating a noise map with the measured experimental values. In particular, for the differences between calculations and measurements, in absolute values, the mean uncertainties were approximately 2 dBA in estimating different long-term noise indicators. For the differences, the mean of the uncertainties obtained via the categorisation method did not present significant differences for the null value for all the analysed noise indicators. Street stratification is a rapid and low-cost approach for road traffic noise mapping without increasing uncertainties.
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