Comparative Assessment of Fluvial Suspended Sediment Concentration Analysis Methods. – Pomázi F., Baranya S. Water,  2020, 12(3):873.

https://doi.org/10.3390/w12030873

The article presents the calibration of the indirect suspended sediment measurement methods tested during the suspended sediment measurements of the Clean Drinking Water Project, the statistical indicators of their reliability, and the comparison of the individual methods, as well as their practical considerations and experiences.

Analytically Supported Numerical Modeling of Horizontal and Radial Collector Wells – F. Székely F., Nyiri, G., Szűcs P., Zákányi B. Journal of Hydrologic Engineering, 2021, 26(12): 04021040.

https://doi.org/10.1061/(ASCE)HE.1943-5584.0002137

Riverbank filtration (RBF) is widely used in drinking water production all over the world. The horizontal and radial collector wells are among the most important water production facilities in case of the RBF aquifers. In this study several types of modeling methods are used to analyze the hydraulic conditions of horizontal and radial collector wells. The unsteady and steady-state flow in homogeneous, infinite, semi-infinite, and square-shaped bounded aquifers are investigated. The effect of delayed gravity response is modeled. Three-dimensional analytical and numerical finite-difference (FD) solution techniques are applied during the simulations to provide more reliable calculation results. Comparative analyses are carried out to optimize the wellbore drawdown in FD simulations. This important value is controlled by the local head loss due to the radial flow in vertical plane normal to the axes of screens. The multimesh FD simulation software FLOWis used for infinite and semi-infinite aquifers, while the MODFLOW Revised Multi-Node Well (MNW2) package is applied to the square-shaped aquifers. The late time partitioning (LTP) method is introduced to estimate the late time drawdown in infinite aquifers using semianalytical steadystate drawdown equations considering circular recharge boundaries. The latter value is derived by the semianalytical CW software. The use of results of various mostly analytically based solutions confirmed or improved the accuracy of the approximate numerical solutions. Such analytical support is vital for proper evaluation of the operation of horizontal and radial collector wells.

Exploring the trend effects of diffuse anthropogenic pollution in a large river passing through a densely populated area – Engloner A.I., Németh K., Dobosy P., Óvári M. Heliyon, 2023, 9(9): e20120.

https://doi.org/10.1016/j.heliyon.2023.e20120

The detection of non-point pollution in large rivers requires high-frequency sampling over a longer period of time, which, however presumably provides data with large spatial and temporal variance. Variability may mean that data sets recorded upstream and downstream from a densely populated area overlap, suggesting at first glance that the urban area did not affect water quality. This study presents a simple way to explore trend-like effects of non-point pollution in the Danube based on data that varied strongly in space and time. For one year, biweekly sampling was carried out upstream and downstream from a large city with negligible emission of untreated wastewater and the surrounding settlements, industrial and agricultural areas.

Although most of the values of the 34 examined physicochemical characteristics fell within the range of data previously published for the Danube, and the mean values of all parameters indicated unpolluted surface water, different water quality was revealed upstream and downstream from the metropolitan area at each sampling time. Since the physicochemical characteristics causing the separation also differed from time to time, univariate tests and consensus ordination were used to determine which variables changed similarly during most of the examined period. With this evaluation method, several diffuse pollutants of anthropogenic origin contaminating the Danube in the long term were identified, such as nitrogen, phosphorus, sulphate, chloride, potassium and vanadium. The results demonstrated that trend-like effects of non-point pollution can be detected even in a large river, where physicochemical measurements can vary strongly in space and time.

Benchmarking the Persistence of Active Pharmaceutical Ingredients in River Systems – M. Honti, M. Zsugyel, C. Seller, K. Fenner. Environ. Sci. Technol. 2023,

https://doi.org/10.1021/acs.est.3c01627

Assessing the persistence of organic micropollutants from field data has been notoriously laborious, requiring extensive data. To overcome some of these obstacles, we developed the concept of persistence benchmarking for large rivers that receive numerous emissions and provide enough residence time to observe the dissipation of compounds.

Planktonic and epilithic prokaryota community compositions in a large temperate river reflect climate change related seasonal shifts – Engloner AI, Vargha M, Kós P, Borsodi AK.. PLoS ONE, 2023, 18(9): e0292057. https://doi.org/10.1371/journal.pone.0292057

In freshwaters, microbial communities are of outstanding importance both from ecological and public health perspectives, however, they are threatened by the impact of global warming. To reveal how different prokaryotic communities in a large temperate river respond to environment conditions related to climate change, the present study provides the first detailed insight into the composition and spatial and year-round temporal variations of planktonic and epilithic prokaryotic community. Microbial diversity was studied using high-throughput next generation amplicon sequencing. Sampling was carried out monthly in the midstream and the littoral zone of the Danube, upstream and downstream from a large urban area. Result demonstrated that river habitats predominantly determine the taxonomic composition of the microbiota; diverse and well-differentiated microbial communities developed in water and epilithon, with higher variance in the latter. The composition of bacterioplankton clearly followed the prolongation of the summer resulting from climate change, while the epilithon community was less responsive. Rising water temperatures was associated with increased abundances of many taxa (such as phylum Actinobacteria, class Gammaproteobacteria and orders Synechococcales, Alteromonadales, Chitinophagales, Pseudomonadales, Rhizobiales and Xanthomonadales), and the composition of the microbiota also reflected changes of several further environmental factors (such as turbidity, TOC, electric conductivity, pH and the concentration of phosphate, sulphate, nitrate, total nitrogen and the dissolved oxygen). The results indicate that shift in microbial community responding to changing environment may be of crucial importance in the decomposition of organic compounds (including pollutants and xenobiotics), the transformation and accumulation of heavy metals and the occurrence of pathogens or antimicrobial resistant organisms.

From Source to Tap: Tracking Microbial Diversity in a Riverbank Filtration-Based Drinking Water Supply System under Changing Hydrological Regimes – Vargha, M.; Róka, E.; Erdélyi, N.; Németh, K.; Nagy-Kovács, Z.; Kós, P.B.; Engloner, A.I… Diversity, 2023, 15:621.

https://doi.org/10.3390/d15050621

In drinking water supply, riverbank filtration (RBF) is an efficient and cost-effective way of eliminating pathogens and micropollutants using a combination of biotic and abiotic processes. Microbial communities in the hyporheic zone both contribute to and are shaped by these processes. Microbial water quality at the point of consumption is in turn influenced by the source water microbiome, water treatment and distribution system. Understanding microbial community shifts from source to tap and the factors behind them is instrumental in maintaining safe drinking water delivery. To this end, microbial communities of an RBF-based drinking water supply system were investigated by metabarcoding in a one-year sampling campaign. Samples were collected from the river, RBF wells, treated water, and a consumer’s tap. Metabarcoding data were analysed in the context of physicochemical and hydrological parameters. Microbial diversity as well as cell count decreased consistently from the surface water to the tap. While Proteobacteria were dominant throughout the water supply system, typical river water microbiome phyla Bacteroidota, Actinobacteria, and Verrucomicrobiota were replaced by Nitrospira, Patescibacteria, Chloroflexi, Acidobacteriota, Methylomicrobilota, and the archaeal phylum Nanoarcheota in well water. Well water communities were differentiated by water chemistry, in wells with high concentration groundwater derived iron, manganese, and sulphate, taxa related to iron and sulphur biogeochemical cycle were predominant, while methane oxidisers characterised the more oxic wells. Chlorine-resistant and filtration-associated taxa (Acidobacteria, Firmicutes, and Bdellovibrionota) emerged after water treatment, and no potentially pathogenic taxa were identified at the point of consumption. River discharge had a distinct impact on well water microbiome indicative of vulnerability to climate change. Low flow conditions were characterised by anaerobic heterotrophic taxa (Woesarchaeales, Aenigmarchaeales, and uncultured bacterial phyla MBNT15 and WOR-1), implying reduced efficiency in the degradation of organic substances. High flow was associated the emergence of typical surface water taxa. Better understanding of microbial diversity in RBF water supply systems contributes to preserving drinking water safety in the future changing environment.

A new statistical method for the comparison of biplots with the same objects and variables. – Engloner A.I., Podani J. Ecological Indicators, 2023, 154:110802.

https://doi.org/10.1016/j.ecolind.2023.110802

Ordinations are compared most commonly by Procrustes methods applicable to points belonging to the same domain, either the objects or the variables describing them. However, no published approach applies to biplots which visualize principal component ordinations of objects and variables simultaneously.

To fill this gap, this paper provides a new procedure based on two fundamental, scale-invariant properties of biplots: the cosine of the angle between the vectors pointing to every pair of objects and variables and the mean of the relative length of the two vectors. The method applies to situations in which the number of objects is the same in all ordinations, the number of variables is also the same and, additionally, there is one-to-one correspondence between the points in the different ordinations. The new method is illustrated with two artificial examples and is also applied to the comparison of biplots obtained from real field data representing samples repeated in the same locations over time.

It is demonstrated that the new method reveals the similarities and differences between alternative biplots obtained for a given set of objects and variables.

We expect that, thanks to the widespread use of principal component analysis in science, the method will receive applications in any studies in which interest lies in the comparison of simultaneous ordinations of objects and variables.