• MeSH
• znečištění vody MeSH

Current models predict increases in High Arctic temperatures and precipitation that will have profound impacts on the Arctic hydrological cycle, including enhanced glacial melt and thawing of active layer soils. However, it remains uncertain how these changes will impact the structure of downstream resident freshwater microbial communities and ensuing microbially driven freshwater ecosystem services. Using the Lake Hazen watershed (Nunavut, Canada; 82°N, 71°W) as a sentinel system, we related microbial community composition (16S rRNA gene sequencing) to physicochemical parameters (e.g. dissolved oxygen and nutrients) over an annual hydrological cycle in three freshwater compartments within the watershed: (i) glacial rivers; (ii) active layer thaw-fed streams and waterbodies and (iii) Lake Hazen, into which (i) and (ii) drain. Microbial communities throughout these freshwater compartments were strongly interconnected, hydrologically, and often correlated with the presence of melt-sourced chemicals (e.g. dissolved inorganic carbon) as the melt season progressed. Within Lake Hazen itself, water column microbial communities were generally stable over spring and summer, despite fluctuating lake physicochemistry, indicating that these communities and the potential ecosystem services they provide therein may be resilient to environmental change. This work helps to establish a baseline understanding of how microbial communities and the ecosystem services they provide in Arctic watersheds might respond to future climate change.

• MeSH
• ekosystém MeSH
• jezera mikrobiologie   MeSH
• klimatické změny MeSH
• mikrobiologie vody * MeSH
• mikrobiota * MeSH
• půda MeSH
• půdní mikrobiologie MeSH
• řeky mikrobiologie   MeSH
• RNA ribozomální 16S MeSH
• roční období MeSH
• sladká voda mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Arktida MeSH
• Nunavut MeSH

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.

• MeSH
• chemické látky znečišťující vodu analýza   MeSH
• chemické techniky analytické MeSH
• monitorování životního prostředí metody   MeSH
• pesticidy analýza   MeSH
• polychlorované bifenyly analýza   MeSH
• řeky chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Argentina MeSH

Spatially distributed modelling of sediment and phosphorus fluxes on a scale of thousands of square kilometers always involves a compromise between the quality of the data input and the complexity of the model that can be applied. WaTEM/SEDEM offers an approach that allows us to target on spatially focused outputs that can easily be implemented in the decision-making process for effective watershed control. The results for a study area covering the watersheds of 58 large reservoirs threatened by eutrophication within the Czech Republic are presented here as an example of the available analyses. The total area of the watersheds is 27,472 km2. After building a complex river topology scheme and estimating the trap efficiencies in all reservoirs within the river networks, we are able to estimate the total transport efficiency of each river unit for any outlet point (terminal reservoir). The sources of the greatest amounts of sediment (phosphorus) can be identified on the scale of single parcels. According the model, the total soil loss in the study area is 7487 Gg year-1 (2.73 Mg ha-1 year-1). The total sediment entry into the river systems in the target area is 1705 Gg year-1 (15.2% of the total soil loss). The total deposition in the 9890 water reservoirs of various sizes in the target area is 1139 Gg year-1. This means that the deposition in the landscape is 5.1× higher than the deposition in the reservoirs within the study area. The mean annual sediment transport by all watershed outlets is 566 Gg year-1. The cost of dredging the sediment would be about 12.8 million EUR year-1. There is great spatial variability in the deposition and transport processes, but it is imperative to provide strengthened soil protection directly on-site, especially in watersheds where the sediment delivery ratio is much higher than the average value. Phosphorus transported by water erosion is an important element in the balances of phosphorus sources in basins. Sewage waters usually play the predominant role in triggering the eutrophication effect, but there are also reservoirs where erosion-based phosphorus plays a major role.

• MeSH
• chemické látky znečišťující vodu analýza   MeSH
• fosfor analýza   MeSH
• geologické sedimenty MeSH
• monitorování životního prostředí * MeSH
• půda * MeSH
• řeky chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

• MeSH
• barva MeSH
• diagnostické zobrazování MeSH
• histologické techniky MeSH
• histologie MeSH
• shluková analýza MeSH
• voda MeSH
• zobrazování trojrozměrné MeSH

With increasing population growth and climate change, de facto reuse practices are predicted to increase globally. We investigated a longitudinal gradient within the Uhlava River, a representative watershed, where de facto reuse is actively occurring, during Fall and Spring seasons when instream flows vary. We observed human pharmaceutical levels in the river to continuously increase from the mountainous areas upstream to downstream locations and a potable intake location, with the highest concentrations found in small tributaries. Significant relationship was identified between mass flow of pharmaceuticals and the size of human populations contributing to wastewater treatment plant discharges. Advanced ozonation and granular activated carbon filtration effectively removed pharmaceuticals from potable source waters. We observed a higher probability of encountering a number of targeted pharmaceuticals during colder Spring months when stream flows were elevated compared to warmer conditions with lower flows in the Fall despite a dilution paradigm routinely applied for surface water quality assessment and management efforts. Such observations translated to greater water quality hazards during these higher Spring flows. Future water monitoring efforts should account for periods when higher chemical uses occur, particularly in the face of climate change for regions experiencing population growth and de facto reuse.

• MeSH
• chemické látky znečišťující vodu * analýza   MeSH
• čištění vody * MeSH
• kvalita vody MeSH
• léčivé přípravky * MeSH
• lidé MeSH
• odpadní voda MeSH
• roční období MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The main topic of this study is a human health risk assessment of a defined exposure scenario in the floodplain soils of the headwater areas of the central European watershed, with the aim of exploring both multivariate and regional data structures. Flood-prone areas are recognized worldwide to be susceptible to contamination and its redistribution. Contributions of various classes of toxic compounds (organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs)) to human health risks were assessed in a screening risk assessment. However, due to the relative nature of our data and a high PAH dominancy over the data ensemble, reliance solely on the standard statistical processing of raw data might lead to incomplete insight into the structure of the multivariate data. Explanatory analysis of the data structure using the compositional approach was found to be beneficial to elucidating human health risk profiles and provided robust evidence that a contrast between agricultural and airborne industrial pollution controlled the whole human toxicological variation of persistent organic pollutants (POPs) in floodplain soils. These results were effectively quantified with the subcomposition of benzo(a)pyrene, DDT, and alpha-hexachlorocyclohexane (aHCH), allowing for an interpretation of structural differences in regional pollution patterns, which conferred different extents and compositions of human health risks in floodplain soils.

• MeSH
• algoritmy MeSH
• chlorované uhlovodíky analýza   MeSH
• hexachlorcyklohexan analýza   MeSH
• látky znečišťující půdu analýza   MeSH
• látky znečišťující životní prostředí analýza   MeSH
• lidé MeSH
• monitorování životního prostředí * MeSH
• pesticidy analýza   MeSH
• polychlorované bifenyly analýza   MeSH
• polycyklické aromatické uhlovodíky analýza   MeSH
• půda chemie   MeSH
• záplavy * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH

Despite the large number of studies devoted to organic matter dynamics in fluvial ecosystems, the detrital pathways of spring headwater systems remain neglected. In particular, spring wetlands (helocrenes or seepages) might have considerable influence on downstream headwater stream systems due to the alteration of the nutrient and organic matter content of the water. In this study, we examined fine particulate organic matter (FPOM) drained from helocrenic springs to describe its downstream transport. We studied the quantity, nutrient content and physical components of FPOM gathered from the outflowing water using continuous sediment samplers. The nutrient content of local leaf litter deposits, residence time of water in the springs and concentration of dissolved nutrients in spring sources and outflows were also measured to characterize the inputs and outputs of the studied system. The results show that headwater spring wetlands represent a significant source of high-quality FPOM for downstream river networks. The estimated concentration of FPOM (<1000 μm) in the 11 investigated springs was 3.1 ± 2.5 mg.L-1. In general, the FPOM was relatively nutrient-rich (N = 19.25 ± 4.73 mg.L-1; P = 2.04 ± 0.78 mg.L-1; Ca = 9.65 ± 2.63 mg.L-1; S = 4.07 ± 1.16 mg.L-1; C = 278.68 ± 80.81 mg.L-1). The C:N and C:P ratios in the local leaf litter deposits were higher than in FPOM (41.04 ± 14.32 vs. 14.70 ± 2.46 and 591.7 ± 168.83 vs. 154,77 ± 64,73, respectively), indicating that suspended FPOM is more nutritious for consumers. A significant trend in terms of size fractions of FPOM was identified: with decreasing C:N and C:P ratios particle size decreases as well. Overall, the data suggest that the relatively small helocrenes can serve as an organic matter transformers, receiving primary particles and dissolved organic matter, transforming them and favouring their transport downstream. These biotopes may represent a substantial discontinuity of the river continuum at its origin, important for nutrient dynamics and food supply of associated biotic communities.

• MeSH
• monitorování životního prostředí * MeSH
• organické látky analýza   MeSH
• pevné částice analýza   MeSH
• pohyb vody MeSH
• přírodní prameny chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• ekosystém MeSH
• financování vládou MeSH
• zemědělství trendy   MeSH
• znečištění vody ekonomika   prevence a kontrola   MeSH

Stable isotopes of hydrogen (2H) and oxygen (18O) of the water molecule were used to assess the relationship between precipitation, surface water and groundwater in a large Russia/Ukraine trans-boundary river basin. Precipitation was sampled from November 2013 to February 2015, and surface water and groundwater were sampled during high and low flow in 2014. A local meteoric water line was defined for the Ukrainian part of the basin. The isotopic seasonality in precipitation was evident with depletion in heavy isotopes in November-March and an enrichment in April-October, indicating continental and temperature effects. Surface water was enriched in stable water isotopes from upstream to downstream sites due to progressive evaporation. Stable water isotopes in groundwater indicated that recharge occurs mainly during winter and spring. A one-year data set is probably not sufficient to report the seasonality of groundwater recharge, but this survey can be used to identify the stable water isotopes framework in a weakly gauged basin for further hydrological and geochemical studies.

• MeSH
• deuterium analýza   MeSH
• hydrologie metody   MeSH
• izotopy kyslíku analýza   MeSH
• monitorování životního prostředí metody   MeSH
• podzemní voda analýza   chemie   MeSH
• řeky chemie   MeSH
• roční období MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Rusko MeSH
• Ukrajina MeSH