暂无摘要。

We investigated environmental, landscape, and microbial factors that could structure the spatiotemporal variability in the nontarget chemical composition of four riverine systems in the Oregon Coast Range, USA. We hypothesized that the nontarget chemical composition in river water would be structured by broad-scale landscape gradients in each watershed. Instead, only a weak relationship existed between the nontarget chemical composition and land cover gradients. Overall, the effects of microbial communities and environmental variables on chemical composition were nearly twice as large as those of the landscape, and much of the influence of environmental variables on the chemical composition was mediated through the microbial community (i.e., environment affects microbes, which affect chemicals). Therefore, we found little evidence to support our hypothesis that chemical spatiotemporal variability was related to broad-scale landscape gradients. Instead, we found qualitative and quantitative evidence to suggest that chemical spatiotemporal variability of these rivers is controlled by changes in microbial and seasonal hydrologic processes. While the contributions of discrete chemical sources are undeniable, water chemistry is undoubtedly impacted by broad-scale continuous sources. Our results suggest that diagnostic chemical signatures can be developed to monitor ecosystem processes, which are otherwise challenging or impossible to study with existing off-the-shelf sensors.

BACKGROUND: To investigate the feasibility and safety of watershed analysis after target pulmonary vascular occlusion for the wedge resection in patients with non-palpable and non-localizable pure ground-glass nodules during uniport thoracoscopic surgery.
METHODS: A total of 30 patients with pure ground-glass nodules < 1 cm in diameter, localized in the lateral third of the lung parenchyma, were enrolled. Three-dimensional reconstruction of thin-section computed tomography (CT) data was performed using Mimics software before surgery to observe and identify the target pulmonary vessels supplying the lung tissue in the area where the pulmonary nodules were localized and to temporarily block the target pulmonary vessels during surgery. Next, the extent of the watershed was determined with the expansion-collapse method, and finally, wedge resection was performed. After wedge resection of the target lung tissue, the blocked pulmonary vessel was released, thus allowing operators to complete the procedure without damaging pulmonary vessels.
RESULTS: None of the patients experienced postoperative complications. The chest CT of all patients was reviewed six months after the operation, revealing no tumor recurrence.
CONCLUSIONS: Our results suggest that watershed analysis following target pulmonary vascular occlusion for wedge resection in pulmonary pure ground-glass nodules is a safe and feasible approach.

Irrigation water quality has important implications on salinity, ion toxicity, production cost, and crop failures. There is a need for a comprehensive analysis of spatial and temporal dynamics in parameters at a watershed scale. This information is critical for irrigation management in agricultural production. The Lake Uluabat watershed is a significant agricultural area of Turkey, which is studied using monitored water data. Multivariate assessment is performed using cluster analysis (CA), discriminant analysis (DA), principal component analysis (PCA), and factor analysis (FA) to evaluate temporal and spatial variations in water quality in the watershed. The data is processed by clustering, reducing data dimensionality, delineating indicator parameters, assessing source identification, and evaluating temporal changes and spatial patterns. The results show that the most representative discriminant parameters had more than 90.98% validity in both temporal and spatial analyses. Runoff rate (Q) and water temperature (WT) were identified in the temporal study, while spatial analysis showed bicarbonate (HCO3-), sulfate (SO42-), and boron (B3+) as indicators. Salinity, sodicity, boron hazard, and alkalinity affect both spatial and temporal water quality patterns in the watershed. It is observed that continued use of poor-quality irrigation water can adversely affect agriculture and soil health in a watershed. Spatio-temporal relationships in parameters will be useful in sustainable irrigation management and farm planning for improving crop productivity and soil health.

Water monitoring is of great importance, especially for water bodies in agricultural or industrial areas. Grab sampling is a widely used technique for aquatic monitoring but represents only a snapshot of the contaminant levels at a specific point in time. Passive sampling, on the other hand, is an integrative technique that provides an average concentration of contaminants representative of its deployment period. Thus, the current contamination by organochlorine pesticides, polychlorinated biphenyls (PCBs), and some currently used pesticides was assessed along the Quequén Grande River watershed (Argentina) using the integrative silicone rubber passive sampling technique in a year-long study. Silicone rubber samplers were deployed at 6 sampling sites selected according to different land uses (agricultural-livestock production, agricultural and urban activities) during 3 periods in 2014 and 2015. The organochlorine pesticides were dominated by endosulfan (sum of α-, β-endosulfan, endosulfan sulfate = 0.15-23.4 ng/L). The highest endosulfan levels were registered during the pesticide application period (December-March), exceeding the international water quality guidelines for protecting freshwater biota (3 ng/L). Compared with previous reports, no reductions in endosulfan levels were observed at the Quequén Grande River watershed. These results would suggest the illegal use of remaining stocks because water sampling was carried out after endosulfan was banned in Argentina. Chlorpyrifos was the second major pesticide found in water (0.02-4.3 ng/L), associated with its widespread usage on soybean crops. A reduction in levels of legacy pesticides (heptachlors, DDTs, dieldrin, and chlordanes) was evident compared with previous reports from 2007. Levels of PCBs were very low, indicating that probably only minor diffuse sources were still available along the Quequén Grande River watershed. Environ Toxicol Chem 2019;38:340-349. © 2018 SETAC.

Pharmaceutical monitoring (37 pharmaceuticals and 3 human tracers) was conducted in a headwater streams in southwest France, an area characterized by a low population density with an elderly population (30% > 60 years old) and extensive agriculture (cow cattle breeding). Polar Organic Chemical Integrative Sampler (POCIS) were exposed for 14-day consecutive periods in 2016 at three sampling points. Three human wastewater tracers and 20 pharmaceuticals commonly used for human and/or cattle were quantified in headwaters. Succession of small Wastewater Treatment Plant (WWTP), non-collective sanitation, discharges of untreated effluents as well as the river ability to dilute discharged wastewater, mainly explain the pharmaceuticals and human tracers concentrations. Pharmaceutical loads were time-dependent and were higher during cold season due to increase of pharmaceutical consumption. In contrast, better degradation and/or sorption onto river biofilms in warm season induced the decrease of headwater pharmaceutical content. The headwaters streams were contaminated by compounds found in other type of watershed, but β-blocker were the compounds quantified in higher concentration with frequencies of 100%, which was consistent with the elderly population living in the watershed. Specific compounds (sulfamerazine and sulfamethoxazole) used to cattle medical care were detected in waters, but at a low content.

Future shifts in climatic conditions may impact watershed mercury (Hg) dynamics and transport. An ensemble of watershed models was applied in the present study to simulate and evaluate the responses of hydrological and total Hg (THg) fluxes from the landscape to the watershed outlet and in-stream THg concentrations to contrasting climate change projections for a watershed in the southeastern coastal plain of the United States. Simulations were conducted under stationary atmospheric deposition and land cover conditions to explicitly evaluate the effect of projected precipitation and temperature on watershed Hg export (i.e., the flux of Hg at the watershed outlet). Based on downscaled inputs from 2 global circulation models that capture extremes of projected wet (Community Climate System Model, Ver 3 [CCSM3]) and dry (ECHAM4/HOPE-G [ECHO]) conditions for this region, watershed model simulation results suggest a decrease of approximately 19% in ensemble-averaged mean annual watershed THg fluxes using the ECHO climate-change model and an increase of approximately 5% in THg fluxes with the CCSM3 model. Ensemble-averaged mean annual ECHO in-stream THg concentrations increased 20%, while those of CCSM3 decreased by 9% between the baseline and projected simulation periods. Watershed model simulation results using both climate change models suggest that monthly watershed THg fluxes increase during the summer, when projected flow is higher than baseline conditions. The present study\'s multiple watershed model approach underscores the uncertainty associated with climate change response projections and their use in climate change management decisions. Thus, single-model predictions can be misleading, particularly in developmental stages of watershed Hg modeling.