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A lentic microcosm approach to determine the toxicity of DDT and deltamethrin on diatom communities
2022
Kock, Anrich | Smit, Nico J. | Taylor, Jonathan C. | Wolmarans, Nico J. | Wepener, V.
Worldwide the use of pesticides has increased, especially in the industry and agriculture sector even though they contain highly toxic substances. The use of pesticides has various negative effects on the aquatic ecosystem and organisms within these ecosystems. The paper aimed to assess the effects of increased concentrations of malaria vector control insecticides (Dichlorodiphenyltrichloroethane (DDT) and Deltamethrin (DTM)) on the freshwater diatom community structure using a microcosm approach as well as determine whether a mixture (DDT 1:1 Deltamethrin) exposure will have a greater influence on the diatom community when compared to single exposures of these insecticides. Diatoms were exposed to a high and low concentration (based on LC50 data for freshwater Xenopus laevis from the USEPA Ecotox database) of DDT, DTM and a mixture in lentic microcosms over a total period of 28 days. Results indicated that irrespective of exposure concentrations, DDT, DTM and a mixture had negative effects on the diatom community including functionality and vitality as these insecticides induced changes to their chloroplasts. There was an increased percentage dead cells for all exposures compared to the control, with the insecticides having a phototoxic effect on the diatom community. Exposure to the selected insecticides caused a significant decrease in some diatom metrics indicating the negative effects these insecticides have on the diatom metrics. Therefore, diatoms may prove to be useful as bio-indicators in ecotoxicology studies when assessing the effects of any insecticide exposures.
Mostrar más [+] Menos [-]Contributions of meteorology to ozone variations: Application of deep learning and the Kolmogorov-Zurbenko filter
2022
Sadeghi, Bavand | Ghahremanloo, Masoud | Mousavinezhad, Seyedali | Lops, Yannic | Pouyaei, Arman | Choi, Yunsoo
From hourly ozone observations obtained from three regions⸻Houston, Dallas, and West Texas⸻we investigated the contributions of meteorology to changes in surface daily maximum 8-h average (MDA8) ozone from 2000 to 2019. We applied a deep convolutional neural network and Shapely additive explanation (SHAP) to examine the complex underlying nonlinearity between variations of surface ozone and meteorological factors. Results of the models showed that between 2000 and 2019, specific humidity (38% and 27%) and temperature (28% and 37%) contributed the most to ozone formation over the Houston and Dallas metropolitan areas, respectively. On the other hand, the results show that solar radiation (50%) strongly impacted ozone variation over West Texas during this time. Using a combination of the Kolmogorov-Zurbenko (KZ) filter and multiple linear regression, we also evaluated the influence of meteorology on ozone and quantified the contributions of meteorological parameters to trends in surface ozone formation. Our findings showed that in Houston and Dallas, meteorology influenced ozone variations to a large extent. The impacts of meteorology on West Texas, however, showed meteorological factors had fewer influences on ozone variabilities from 2000 to 2019. This study showed that SHAP analysis and the KZ approach can investigate the contributions of the meteorological factors on ozone concentrations and help policymakers enact effective ozone mitigation policies.
Mostrar más [+] Menos [-]Uptake and translocation of synthetic musk fragrances by pea plant grown in sewage sludge-amended soils
2022
Fernandes, Ana Sofia | Azevedo, Tomé | Rocha, Filipe | Nunes, Eugénia | Homem, Vera
Sewage sludges are rich in organic matter and several essential nutrients for plant growth, making them very appealing for application in agricultural soils. However, they may also contain a wide range of emerging pollutants, which has raised concerns about the potential risks of this practice to crops, the environment, and public health - accumulation in soils and/or plant uptake and translocation of contaminants. Therefore, there is a need to study plant-soil interactions and assess the uptake potential of these contaminants by food crops to better understand these risks. The main aim of this work was to assess the possible drawbacks of sludge application to cropland, by observing the impact on the growth and yield of a model crop (pea plant - Pisum sativum) grown over an 86-day greenhouse experiment and by assessing the uptake potential of synthetic musk fragrances. Different sewage sludge application rates (4–30-ton ha⁻¹) and initial concentrations of contaminants were tested. The application of sludge yielded benefits to the cultivated plants, finding improved crop productivity with an application rate of 30-ton ha⁻¹. At the end of the experiment, soil samples and plants separated into sections were analysed using a QuEChERS extraction methodology followed by gas chromatography-mass spectrometry (GC-MS) quantification. Galaxolide (HHCB) and tonalide (AHTN) underwent uptake by the plant roots, having been detected in concentrations up to 346 ng g⁻¹ on a dry weight basis (dw), but only HHCB was detected in above ground tissues. At the end, a decrease in the levels of synthetic musks in the amended soils (>80% in several instances) was observed. Assuming the worst-case scenario, no risk to human health was observed from the ingestion of peas grown on sewage sludge-amended soils. However, a soil hazard quotient analysis yielded worryingly high quotient values for AHTN in nearly all tested conditions.
Mostrar más [+] Menos [-]Acute exposure to perfluorooctane sulfonate exacerbates heat-induced oxidative stress in a tropical coral species
2022
Bednarz, V.N. | Choyke, S. | Marangoni, L.F.B. | Otto, E.I. | Béraud, E. | Metian, M. | Tolosa, I. | Ferrier-Pagès, C.
Perfluorooctane sulfonate (PFOS) is among the most commonly per- and poly-fluoroalkyl substances (PFAS) found in environmental samples. Nevertheless, the effect of this legacy persistent organic contaminant has never been investigated on corals to date. Corals are the keystone organisms of coral reef ecosystems and sensitive to rising ocean temperatures, but it is not understood how the combination of elevated temperature and PFOS exposure will affect them. Therefore, the aims of the present study were (1) to evaluate the time-dependent bioconcentration and depuration of PFOS in the scleractinian coral Stylophora pistillata using a range of PFOS exposure concentrations, and (2) to assess the individual and combined effects of PFOS exposure and elevated seawater temperature on key physiological parameters of the corals. Our results show that the coral S. pistillata rapidly bioconcentrates PFOS from the seawater and eliminates it 14 days after ceasing the exposure. We also observed an antagonistic effect between elevated temperature and PFOS exposure. Indeed, a significantly reduced PFOS bioconcentration was observed at high temperature, likely due to a loss of symbionts and a higher removal of mucus compared to ambient temperature. Finally, concentrations of PFOS consistent with ranges observed in surface waters were non-lethal to corals, in the absence of other stressors. However, PFOS increased lipid peroxidation in coral tissue, which is an indicator of oxidative stress and enhanced the thermal stress-induced impairment of coral physiology. This study provides valuable insights into the combined effects of PFOS exposure and ocean warming for coral's physiology. PFOS is usually the most prevalent but not the only PFAS defected in reef waters, and thus it will be also important to monitor PFAS mixture concentrations in the oceans and to study their combined effects on aquatic wildlife.
Mostrar más [+] Menos [-]Effect of apparent temperature on hospitalization from a spectrum of cardiovascular diseases in rural residents in Fujian, China
2022
Zhan, Zhi-Ying | Xue, Zhong | Yang, Jun | Ding, Zan | Xie, Xiao-Xu | Zheng, Zhen-Quan | Hu, Zhi-Jian
Cardiovascular disease (CVD) is a leading threat to global public health. Although associations between temperature and CVD hospitalization have been suggested for developed countries, limited evidence is available for developing countries or rural residents. Moreover, the effect of apparent temperature (AT) on the spectrum of cause-specific CVDs remains unknown. Based on 2,024,147 CVD hospitalizations for rural residents from eight regions in Fujian Province, China, during 2010–2016, a quasi-Poisson regression with distributed lag non-linear model was fitted to estimate the AT effect on daily CVD hospitalization for each region, and then pooled in a meta-regression that included regional indicators related to rural residents. Stratified analyses were performed according to the cause of hospitalization, sex and age groups. Finally, we calculated the fraction of CVD hospitalizations attributable to AT, as a reflection of the burden associated with AT. The heat effect appeared at lag 0–1 days, with 19% (95% CI, 11–26%) increased risk of CVD hospitalization, which was worse for ischemic heart disease, heart failure, arrhythmias and ischemic stroke. The decreased AT was associated with increase of hemorrhagic stroke at lag 0–28 days. People aged 65 and above suffered more from the heat effect on cardiovascular and cerebrovascular diseases. Regions with a lower gross value of agricultural production, rural residents’ per capita net income, number of air conditioners and water heaters were more susceptible. A large number of hospitalizations were attributable to heat for most subcategories. High AT level increased CVD hospitalization, and the subcategories had different susceptibilities. The effects were modified by individual and regional characteristics. These findings have important implications for the development of targeted interventions and for hospital service planning.
Mostrar más [+] Menos [-]Spatiotemporal occurrence of phthalate esters in stormwater drains of Hong Kong, China: Mass loading and source identification
2022
Cao, Yaru | Xu, Shaopeng | Zhang, Kai | Lin, Huiju | Wu, Rongben | Lao, Jia-Yong | Tao, Danyang | Liu, Mengyang | Leung, Kenneth M.Y. | Lam, Paul K.S.
Urban stormwater is an important pathway for transporting anthropogenic pollutants to water bodies. Phthalate esters (PAEs) are endocrine disruptors owing to their estrogenic activity and potential carcinogenicity and their ubiquitous presence has garnered global interest. However, their transportation by urban stormwater has been largely overlooked. This study, for the first time, investigated 15 PAEs in stormwater from six major stormwater drains in the highly urbanized Hong Kong, a major metropolitan city in China. The results showed that PAEs were ubiquitous in the stormwater of Hong Kong, with total concentrations (∑₁₅PAEs) spanning from 195 to 80,500 ng/L. Bis(2-n-butoxyethyl) phthalate (DBEP), diisopentyl phthalate (DiPP), dicyclohexyl phthalate (DCHP) and di-n-pentyl phthalate (DnPP) were detected in stormwater for the first time. Spatial variations in PAEs were observed among different stormwater drains, possibly due to the different land use patterns and intensities of human activities in their respective catchments. The highest and lowest levels of ∑₁₅PAEs were found in Kwai Chung (3860 ± 1960 ng/L) and the Ng Tung River (672 ± 557 ng/L), respectively. Additionally, significantly higher concentrations of ∑₁₅PAEs in stormwater were found in the wet season (2520 ± 2050 ng/L) than in the dry season (947 ± 904 ng/L). Principal component analysis classified domestic and industrial origins as two important sources of PAEs in the stormwater of Hong Kong. Stormwater played a crucial role in transporting PAEs, with an estimated annual flux of 0.705–29.4 kg. Thus, possible stormwater management measures were proposed to protect the receiving environment and local ecosystems from stormwater.
Mostrar más [+] Menos [-]Acute damage from the degradation of Ulva prolifera on the environmental microbiota, intestinal microbiota and transcriptome of Japanese flounder Paralichthys olivaceus
2022
Fan, Qingxin | Shi, Kunpeng | Zhan, Min | Xu, Qian | Liu, Xinbao | Li, Zhujun | Liu, Hongning | Xia, Yanting | Chen, Yadong | Shi, Xiaoyong | Sha, Zhenxia
Green tide outbreaks caused by overgrowth of Ulva prolifera in the Yellow Sea of China can cause serious ecological stress with concomitant economic hardships, especially to marine fisheries. In this study, short-term effects (14 days) were evaluated using fresh algae U. prolifera (FU), and a 7-day assessment of the effects of decomposing U. prolifera (DU) algal effluent was conducted to determine the effects on the environmental and intestinal microbiota, intestinal transcriptome and mortality of the commercial marine benthic fish, Japanese flounder (Paralichthys olivaceus). The results revealed that algal degradation altered the microbial community structure of fish farm water and fish intestines and increased the relative abundance of the pathogens Flavobacteriaceae in water and Vibrio in fish intestines. Fish intestinal tissue structure appeared to be damaged, as indicated in pathological sections, and transcriptome analysis showed intestinal inflammation after exposure, which may have caused an increase in fish mortality. The degradation of U. prolifera led to a bloom of potential pathogenic bacteria and the inflammation of fish intestines, which resulted in disease in the flounder population that reduced fish harvests and might pose a potential health threat.
Mostrar más [+] Menos [-]Organ-specific accumulation of cadmium and zinc in Gammarus fossarum exposed to environmentally relevant metal concentrations
2022
Gestin, Ophélia | Lopes, Christelle | Delorme, Nicolas | Garnero, Laura | Geffard, Olivier | Lacoue-Labarthe, Thomas
One of the best approaches for improving the assessment of metal toxicity in aquatic organisms is to study their organotropism (i.e., the distribution of metals among organs) through a dynamical approach (i.e., via kinetic experiments of metal bioaccumulation), to identify the tissues/organs that play a key role in metal regulation (e.g., storage or excretion). This study aims at comparing the organ-specific metal accumulation of a non-essential (Cd) and an essential metal (Zn), at their environmentally relevant exposure concentrations, in the gammarid Gammarus fossarum. Gammarids were exposed for 7 days to ¹⁰⁹Cd- or ⁶⁵Zn-radiolabeled water at a concentration of 52.1 and 416 ng.L⁻¹ (stable equivalent), respectively, and then placed in clean water for 21 days. At different time intervals, the target organs (i.e., caeca, cephalons, intestines, gills, and remaining tissues) were collected and ¹⁰⁹Cd or ⁶⁵Zn contents were quantified by gamma-spectrometry. A one-compartment toxicokinetic (TK) model was fitted by Bayesian inference to each organ/metal dataset in order to establish TK parameters. Our results indicate: i) a contrasting distribution pattern of concentrations at the end of the accumulation phase (7ᵗʰ day): gills > caeca ≈ intestines > cephalons > remaining tissues for Cd and intestines > caeca > gills > cephalons > remaining tissues for Zn; ii) a slower elimination of Cd than of Zn by all organs, especially in the gills in which the Cd concentration remained constant during the 21-day depuration phase, whereas Zn concentrations decreased sharply in all organs after 24 h in the depuration phase; iii) a major role of intestines in the uptake of waterborne Cd and Zn at environmentally relevant concentrations.
Mostrar más [+] Menos [-]Prevention and control of coronavirus disease 2019 (COVID-19) in public places
2022
Pan, Lijun | Wang, Jiao | Wang, Xianliang | Ji, John S. | Ye, Dan | Shen, Jin | Li, Li | Liu, Hang | Zhang, Liubo | Shi, Xiaoming | Wang, Lin
Public places favor the transmission of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) due to dense population, large personal mobility, and higher contact opportunities. In order to protect the health of general public in operating public places during COVID-19 pandemic, this study proposed general precautions and control strategies from perspective of operation management, social distancing, cleaning and disinfection, and personal protection. In addition, with regard of risk level, specific precautions and control strategies were proposed for living service places, outdoor places, and confined places. The comprehensive application of above recommendations could effectively interrupt the spread of COVID-19, and protect the health of general public in public places.This study proposed general and specific precautions and control strategies in public places during COVID-19, and suggested further improvement of pandemic response.
Mostrar más [+] Menos [-]Computational and data mining studies to understand the distribution and dynamics of Temoneria (TEM) β-lactamase and their interaction with β-lactam and β-lactamase inhibitors
2022
Gehlot, Priyanka | P, Hariprasad
β-lactams are large group of antibiotics widely used to suppress the bacterial growth by inhibiting cell wall synthesis. Bacterial resistance against β-lactam antibiotics is primarily mediated through the production of Temoneria (TEM) β-lactamase (BLs), with almost 474 variants identified in Lactamase Engineering Database (LacED). The present study aims to develop a model to track the evolution of TEM BLs and their interactions with β-lactam and BLs inhibitors through data mining and computational approaches. Further, the model will be used to predict the effective combinations of β-lactam and BLs inhibitors to treat the bacterial infection harbouring emerging variants of β-lactamase. The molecular docking study results demonstrated that most TEM mutants recorded the least binding energy to penicillin and cephalosporin (I/II/III/IV/V generations) class of antibiotics. On the contrary, the same mutants recorded higher binding energy to carbapenem and Monobactam class of antibiotics. Among the BLs inhibitors, tazobactam recorded the least binding energy against most of the TEM mutants, indicating that it can lower the catalytic activity of TEM BLs, thereby potentiating antibiotic action. Similarly, data mining work has assisted us in creating a database of TEM mutants that has comprehensive data on mutations, bacterial diversity, Km, MIC, and IRT types. It has been noted that earlier released antibiotics like amoxicillin and ampicillin had lower Km and higher MIC values, which indicates the prevalence of bacterial resistance. By analysing the differential binding energy (ΔBE) of the selected TEM mutants against β-lactam and BLs inhibitors, the most effective combination of β-lactam (carbapenem and monobactam class of antibiotics) and BLs inhibitors (tazobactam) was identified, to cure bacterial diseases/infections and to prevent similar antibiotic resistance outbreaks. Therefore, our study opens a new avenue in developing strategies to manage antibiotic resistance in bacteria.
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