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Resultados 621-630 de 6,531
Predicting nanotoxicity by an integrated machine learning and metabolomics approach
2020
Peng, Ting | Wei, Changhong | Yu, Fubo | Xu, Jing | Zhou, Qixing | Shi, Tonglei | Hu, Xiangang
Predicting the biological responses to engineered nanoparticles (ENPs) is critical to their environmental health assessment. The disturbances of metabolic pathways reflect the global profile of biological responses to ENPs but are difficult to predict due to the highly heterogeneous data from complicated biological systems and various ENP properties. Herein, integrating multiple machine learning models and metabolomics enabled accurate prediction of the disturbance of metabolic pathways induced by 33 ENPs. Screening nine typical properties of ENPs identified type and size as the top features determining the effects on metabolic pathways. Similarity network analysis and decision tree models overcame the highly heterogeneous data sources to visualize and judge the occurrence of metabolic pathways depending on the sorting priority features. The model accuracy was verified by animal experiments and reached 75%–100%, even for the prediction of ENPs outside of databases. The models also predicted metabolic pathway-related histopathology. This work provides an approach for the quick assessment of environmental health risks induced by known and unknown ENPs.
Mostrar más [+] Menos [-]Emerging polar pollutants in groundwater: Potential impact of urban stormwater infiltration practices
2020
Pinasseau, Lucie | Wiest, Laure | Volatier, Laurence | Mermillod-Blondin, Florian | Vulliet, Emmanuelle
The quality of groundwater (GW) resources is decreasing partly due to chemical contaminations from a wide range of activities, such as industrial and agricultural enterprises and changes in land-use. In urban areas, one potential major pathway of GW contamination is associated with urban water management practices based on stormwater runoff infiltration systems (SIS). Data on the performance of the upper layer of soil and the unsaturated zone of infiltration basins to limit the contamination of GW by hydrophilic compounds are lacking. With this aim, the impact of infiltration practices on GW contamination was assessed for 12 pesticides and 4 pharmaceuticals selected according to their ecotoxicological relevance and their likelihood of being present in urban stormwater and GW. For this purpose, 3 campaigns were conducted at 4 SIS during storm events. For each campaign, passive samplers based on the use of Empore™ disk were deployed in GW wells upstream and downstream of SIS, as well as in the stormwater runoff entering the infiltration basins. Upstream and downstream GW contaminations were compared to evaluate the potential effect of SIS on GW contamination and possible relationships with stormwater runoff composition were examined. Our results showed two interesting opposite trends: (i) carbendazim, diuron, fluopyram, imidacloprid and lamotrigine had concentrations significantly increasing in GW impacted by infiltration, indicating a contribution of SIS to GW contamination, (ii) atrazine, simazine and 2 transformation products exhibited concentrations significantly decreasing with infiltration due to a probable dilution of historic GW contaminants with infiltrated stormwater runoff. The other 7 contaminants showed no general trend. This study demonstrates that passive samplers deployed in GW wells enabled the capture of emerging polar pollutants present at very low concentrations and allowed the assessment of infiltration practices on GW quality. New data on GW and urban stormwater are provided for poorly studied hazardous compounds.
Mostrar más [+] Menos [-]Trace elements in sediments and fish from Atrato River: an ecosystem with legal rights impacted by gold mining at the Colombian Pacific
2020
Palacios-Torres, Yuber | de la Rosa, Jesus D. | Olivero-Verbel, Jesus
The Atrato watershed is a rainforest that supports exceptional wildlife species and is considered one of the most biodiversity-rich areas on the planet, currently threatened by massive gold mining. Aimed to protect this natural resource, the Constitutional Court of Colombia declared the river subject to rights. The objective of this study was to quantify trace elements in sediments and fish from Atrato watershed, assessing their environmental and human health risk. Forty-two trace elements were quantified using ICP-MS. Thirty-one elements increased their concentration downstream the river. Concentration Factors (CF) suggest sediments were moderately polluted by Cr, Cu, Cd, and strongly polluted by As. Most stations had Cr (98%) and Ni (78%) concentrations greater than the Probable Effect Concentration (PEC) criteria. Together, toxic elements generate a Pollution Load Index (PLI) and a Potential Ecological Risk Index (RI) that categorized 54% of the sediments as polluted, and 90% as moderate polluted, respectively. Hemiancistrus wilsoni, a low trophic guild fish species, had the greater average levels for Ni, Cu, As and Cd, among other elements. Rubidium and Cs showed a positive correlation with fish trophic level, suggesting these two metals biomagnify in the food chain. The Hazard Quotient (HQ) for As was greater than 1 for several species, indicating a potential risk to human health. Collectively, data suggest gold mining carried out in this biodiversity hotspot releases toxic elements that have abrogated sediment quality in Atrato River, and their incorporation in the trophic chain constitutes a large threat on environmental and human health due to fish consumption. Urgent legal and civil actions should be implemented to halt massive mining-driven deforestation to enforce Atrato River rights.
Mostrar más [+] Menos [-]Comparison of arsenic fractions and health risks in PM2.5 before and after coal-gas replacement
2020
Xie, Jiao-Jiao | Yuan, Chun-Gang | Xie, Jin | Niu, Xiao-Dong | Zhang, Xu-Rui | Zhang, Ke-Gang | Xu, Pei-Yao | Ma, Xiao-Ying | Lv, Xiang-Bing
Coal-Gas replacement project has been implemented to decrease haze pollution in China in recent years. Airborne arsenic (As) mostly originates from coal burning processes. It is noteworthy to compare the distribution of arsenic fraction in PM₂.₅ before and after coal-gas replacement. Eighty PM₂.₅ samples were collected in Baoding in December 2016 (coal dominated year) and December 2017 (gas dominated year) at different functional areas including residential area (RA), industrial area (IA), suburb (SB), roadside (ST) and Botanical Garden Park (BG). The fraction, bioavailability and health risk of As in the PM₂.₅ samples were investigated and compared between these two years. Arsenic was mainly distributed in the non-specifically sorbed fraction (F1) and the residual fraction (F5). However, the proportion of F1 to the total As in 2017 was higher than that in 2016, while the proportion of As in the amorphous and poorly-crystalline hydrous oxides of Fe and Al fraction (F3) in 2017 was lower. The distributions of fraction and bioavailability showed temporal and spatial characteristics. The total concentration and bioavailability of As in SB and IA were significantly higher than those in RA, ST and BG. The BF (Bioavailability Factor) values of As ranged from 0.30 to 0.61. Health risk assessment indicated that the hazard quotient (HQ) and carcinogenic risk (CR) of As in PM₂.₅ significantly decreased after coal-gas replacement.
Mostrar más [+] Menos [-]Emission estimation and fate modelling of three typical pesticides in Dongjiang River basin, China
2020
Zhang, Bing | Zhang, Qian-Qian | Zhang, Shao-Xuan | Xing, Cheng | Ying, Guang-Guo
Pesticides are widely and intensively used in the world for crops protection. High pesticide loadings can potentially pollute the water resource. However, little is known about the usage, environmental emission and fate of pesticides in river basins. Here, we firstly established a pesticide emission estimation method, and investigated the environmental fate of three commonly used pesticides (chlorpyrifos, triazophos, and isoprothiolane) in Dongjiang River basin, southern China using mathematical modelling approach in combination with field monitoring. The distributed hydrological model SWAT (Soil and Water Assessment Tool) was applied to model the emission of the target pesticides from farmland to stream water, and their fate in the basin. A satisfactory model calibration for flow and suspended sediment was obtained based on eight-year observation data of four hydrological monitoring stations in Dongjiang River basin. The differences between the simulation and observation of pesticides were almost within an order of magnitude, including more than 53% differences within 0.5 order of magnitude. In the river basin, 78860 kg of chlorpyrifos, 54990 kg of triazophos and 35320 kg of isoprothiolane were sprayed onto the crops, the estimated annual emissions of the basin come up to 1801 kg, 3779 kg, and 2330 kg under the conditions of rainfall, surface runoff and percolation. After a series of environmental processes including settlement and degradation within the channels, the predicted export masses for chlorpyrifos, triazophos and isoprothiolane were reduced to 266 kg, 1858 kg, 1350 kg, respectively. Successful prediction suggests that the reliable estimation method combing the SWAT modelling can help us understand the source, concentration levels and fate of pesticides in river basin in different scales. Combing the method of emission and fate modelling method we proposed, countries and regions lacking pesticide-application database can facilitate better management of pesticides.
Mostrar más [+] Menos [-]Effect of dibutyl phthalate on microbial function diversity and enzyme activity in wheat rhizosphere and non-rhizosphere soils
2020
Gao, Minling | Dong, Youming | Zhang, Ze | Song, Zhengguo
The pollution of farm soils by the plasticizer dibutyl phthalate (DBP) should be researched owing to the extensive use of plastic film. We investigated the influence of DBP on microbial communities and enzyme activities in rhizosphere and non-rhizosphere soil during the different growth stages of wheat and determined the response through simulations. The results indicated that protease, polyphenol oxidase, and β-glucosidase activity in soil decreased with increasing DBP dosage, while dehydrogenase, urease, and acid phosphatase activities increased. Moreover, the effects of DBP on soil enzyme activity gradually weakened with DBP degradation. Dibutyl phthalate has a certain inhibitory effect on the activity, diversity, and heterogeneity of microorganisms in soil. In addition, DBP can increase the utilization of amines and carboxylic acids and decrease the utilization of carbohydrates and amino acids by soil microorganisms. According to the Gaussian and molecular docking analysis, we considered that monobutyl phthalate and DBP could affect the utilization of amino acids by Proteobacteria. The enzyme activity, microbial activity, and heterogeneity of rhizosphere soil were higher than those of non-rhizosphere soil. Microbial carbon source utilization in rhizosphere and non-rhizosphere soils depends on wheat growth, soil type, and DBP dosage. Owing to the widespread presence of DBP in agriculture, negative effects of phthalic acid esters should be considered in relation to soil quality and food safety in future.
Mostrar más [+] Menos [-]Water column nutrient concentrations are related to excretion by benthic invertebrates in Lake Taihu, China
2020
Peng, Kai | Qin, Boqiang | Cai, Yongjiu | Gong, Zhijun | Jeppesen, Erik
Internal release of nutrients is an important contributor to the nutrient dynamics in shallow eutrophic lakes. Zoobenthic organisms may contribute to this release by excreting nutrients to the overlaying water. Based on experiments and using results from previous experimental studies as well as field monitoring density data from 2007 to 2017, we calculated the annual and seasonal nutrient excretions of the two most common macroinvertebrates (Corbicula fluminea and Limnodrilus hoffmeisteri) in Lake Taihu, China. We compared these rates with the concentrations of NH₄–N, total nitrogen (TN), PO₄–P and total phosphorus (TP) in the lake water as well as with previous results of release rates from undisturbed sediments collected in the lake. The spatial distribution of nutrient excretion by the two invertebrate species varied markedly among sites and years. Regression analyses revealed significant relationships between total nutrient excretions by these two species and the concentrations of NH₄–N, TN, PO₄–P and TP in the lake, but with seasonal differences. The relationship was overall strongest in winter, followed by spring, and weakest in summer and autumn. The flux of NH₄–N and PO₄–P released by the two macroinvertebrate species were equivalent to as much as 50% and 66%, respectively, of the sediment release recorded in lab experiments under undisturbed conditions; however, the percentages would be somewhat lower under field conditions where the sediment is subjected to frequent wind-induced resuspension and fish disturbance, enhancing the release rates. The release declined during the study period due to a reduction in the density of macroinvertebrates, perhaps indicating increasing stocking of fish since 2007. Our results indicate that benthic invertebrates are important contributor to the internal loading in shallow eutrophic lakes.
Mostrar más [+] Menos [-]Tossed ‘good luck’ coins as vectors for anthropogenic pollution into aquatic environment
2020
Martínez, Alejandro | Di Cesare, Andrea | Mari-Mena, Neus | García-Gómez, Guillermo | Garcia-Herrero, Alvaro | Corno, Gianluca | Fontaneto, Diego | Eckert, Ester M.
Superstition has it that tossing coins into wells or fountains brings good luck, thereby causing a potential accumulation of microbially contaminated metal particles in the water. Here, we characterized the microbiota and the resistance profile in biofilm on such coins and their surrounding sediments. The study site was a tidal marine lake within a touristic center located in a natural reserve area. Notwithstanding the fact that coin-related biofilms were dominated by typical marine taxa, coin biofilms had specific microbial communities that were different from the communities of the surrounding sediment. Moreover, the communities were different depending on whether the coin were made mainly of steel or of copper. Sequences affiliated with putative pathogens were found on every third coin but were not found in the surrounding sediment. Antibiotic resistance genes (ARGs) were detected on most of the coins, and interestingly, sediments close to the area where coins accumulate had a higher frequency of ARGs. We suggest that the surface of the coins might offer a niche for ARGs and faecal bacteria to survive, and, thus, tossed coins are a potential source and vector for ARGs into the surrounding environment.
Mostrar más [+] Menos [-]Biotransformation of 2,4,6-Trinitrotoluene by Pseudomonas sp. TNT3 isolated from Deception Island, Antarctica
2020
Cabrera, Ma Ángeles | Márquez, Sebastián L. | Quezada, Carolina P. | Osorio, Manuel I. | Castro-Nallar, Eduardo | González-Nilo, Fernando D. | Pérez-Donoso, José M.
2,4,6-Trinitrotoluene (TNT) is a nitroaromatic explosive, highly toxic and mutagenic for organisms. In this study, we report for the first time the screening and isolation of TNT-degrading bacteria from Antarctic environmental samples with potential use as bioremediation agents. Ten TNT-degrading bacterial strains were isolated from Deception Island. Among them, Pseudomonas sp. TNT3 was selected as the best candidate since it showed the highest tolerance, growth, and TNT biotransformation capabilities. Our results showed that TNT biotransformation involves the reduction of the nitro groups. Additionally, Pseudomonas sp. TNT3 was capable of transforming 100 mg/L TNT within 48 h at 28 °C, showing higher biotransformation capability than Pseudomonas putida KT2440, a known TNT-degrading bacterium. Functional annotation of Pseudomonas sp. TNT3 genome revealed a versatile set of molecular functions involved in xenobiotic degradation pathways. Two putative xenobiotic reductases (XenA_TNT3 and XenB_TNT3) were identified by means of homology searches and phylogenetic relationships. These enzymes were also characterized at molecular level using homology modelling and molecular dynamics simulations. Both enzymes share different levels of sequence similarity with other previously described TNT-degrading enzymes and with their closest potential homologues in databases.
Mostrar más [+] Menos [-]Association between proximity to industrial chemical installations and cancer mortality in Spain
2020
Ayuso-Álvarez, Ana | García-Pérez, Javier | Triviño Juárez, José Matías | Larrinaga-Torrontegui, Unai | González Sánchez, Mario | Ramis, Rebeca | Boldo, Elena | López-Abente, Gonzalo | Galán, Iñaki | Fernández-Navarro, Pablo
It is likely that pollution from chemical facilities will affect the health of any exposed population; however, the majority of scientific evidence available has focused on occupational exposure rather than environmental. Consequently, this study assessed whether there could have been an excess of cancer-related mortality associated with environmental exposure to pollution from chemical installations – for populations residing in municipalities in the vicinity of chemical industries. To this end, we designed an ecological study which assessed municipal mortality due to 32 types of cancer in the period from 1999 to 2008. The exposure to pollution was estimated using distance from the facilities to the centroid of the municipality as a proxy for exposure. In order to assess any increased cancer mortality risk in municipalities potentially exposed to chemical facilities pollution (situated at a distance of ≤5 km from a chemical installation), we employed Bayesian Hierarchical Poisson Regression Models. This included two Bayesian inference methods: Integrated Nested Laplace Approximations (INLA) and Markov Chain Monte Carlo (MCMC, for validation). The reference category consisted of municipalities beyond the 5 km limit. We found higher mortality risk (relative risk, RR; estimated by INLA, 95% credible interval, 95%CrI) for both sexes for colorectal (RR, 1.09; 95%CrI, 1.05–1.15), gallbladder (1.14; 1.03–1.27), and ovarian cancers (1.10; 1.02–1.20) associated with organic chemical installations. Notably, pleural cancer (2.27; 1.49–3.41) in both sexes was related to fertilizer facilities. Associations were found for women, specifically for ovarian (1.11; 1.01–1.22) and breast cancers (1.06; 1.00–1.13) in the proximity of explosives/pyrotechnics installations; increased breast cancer mortality risk (1.10; 1.03–1.18) was associated with proximity to inorganic chemical installations. The results suggest that environmental exposure to pollutants from some types of chemical facilities may be associated with increased mortality from several different types of cancer.
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