Research

20 pages, 2603 KiB

Open AccessArticle

The Importance of Enterococci in the Monitoring of Fecal Pollution in River Water in Forests and Urban Areas

by Anna Gotkowska-Płachta and Iwona Gołaś

Water 2023, 15(21), 3708; https://doi.org/10.3390/w15213708 - 24 Oct 2023

Viewed by 1253

The aim of this study was to determine the spatial distribution of enterococci as indicators of fecal pollution in river water in forest reserves and urban areas. The biodiversity, multidrug resistance, and virulence of enterococci were monitored using conventional and molecular methods, including [...] Read more.

The aim of this study was to determine the spatial distribution of enterococci as indicators of fecal pollution in river water in forest reserves and urban areas. The biodiversity, multidrug resistance, and virulence of enterococci were monitored using conventional and molecular methods, including fluorescence in situ hybridization (FISH). Enterococcal (ENT) counts determined via the FISH method were several thousand times higher than those determined by the culture-based method. This observation points to the abundance of viable but non-culturable (VBNC) bacteria that are often more toxic. Water from the river source was characterized by the lowest number of multidrug-resistant and virulent enterococcal strains. The abundance of the analyzed bacteria was highest (more than 50% of the strains) in the area where treated wastewater was evacuated to the river. Statistical analysis confirmed the presence of relationships between these environments. Pathogenic enterococci, which are not effectively eliminated during wastewater treatment, spread in the river continuum, thus posing a health threat to humans and animals. A combination of conventional and molecular techniques for the identification of bacteria supports a rapid and reliable assessment of pollution sources in the examined environment and the implementation of protective measures. Full article

(This article belongs to the Special Issue Lake Eutrophication: Causes, Monitoring and Restoration)

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23 pages, 9428 KiB

Open AccessArticle

Combination of Measures to Restore Eutrophic Urban Ponds in The Netherlands

by Miquel Lürling, Frank van Oosterhout, Maíra Mucci and Guido Waajen

Water 2023, 15(20), 3599; https://doi.org/10.3390/w15203599 - 14 Oct 2023

Viewed by 1267

Abstract

Urban ponds provide the most important public contact with surface waters, implying that good water quality is crucial to the quality of urban life. Three eutrophic urban ponds in the south of The Netherlands with a long history of eutrophication-related nuisance were studied [...] Read more.

Urban ponds provide the most important public contact with surface waters, implying that good water quality is crucial to the quality of urban life. Three eutrophic urban ponds in the south of The Netherlands with a long history of eutrophication-related nuisance were studied and subjected to mitigating measures. The external nutrient load from a mixed sewer overflow to one of the ponds had already been dismantled prior to the study, in a second pond it was dismantled during, while in the third pond the major nutrient source (stormwater run-off from impervious surfaces) was left untouched. In order to rehabilitate the ponds, all were dredged to reduce the internal loading, the fish biomass was reduced, the banks were softened, macrophytes were planted, users were advised to minimize the feeding of the fish and waterfowl, and the external nutrient load was reduced in two of the ponds. The two ponds in which the major external load was reduced showed strongly improved water quality after the additional in-pond measures. In contrast, the pond with ongoing external loading from stormwater run-off showed only marginally improved water quality. This study underpins that stormwater run-off can be polluting and that mitigating measures should only be implemented when the system analysis has revealed their feasibility. Full article

(This article belongs to the Special Issue Lake Eutrophication: Causes, Monitoring and Restoration)

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11 pages, 2872 KiB

Open AccessArticle

Use of Meltblown Nonwoven Fabric Filter for Stormwater Runoff Treatment

by Jaime A. Cárdenas Sánchez, Hunter Szewczyk, Judy Assaad, Carlos Zimeri, Eunkyoung Shim, Xiaomeng Fang and Kyana R. L. Young

Water 2023, 15(2), 242; https://doi.org/10.3390/w15020242 - 05 Jan 2023

Viewed by 2260

Abstract

Anthropogenic activities (e.g., rural urbanization) play major roles in preventing the achievement of sustainable water quality, where eutrophication—the exacerbation of increase in nutrient concentrations combined with warmer temperatures and lower light availability, leading to the dense growth of plant life depleting the amount [...] Read more.

Anthropogenic activities (e.g., rural urbanization) play major roles in preventing the achievement of sustainable water quality, where eutrophication—the exacerbation of increase in nutrient concentrations combined with warmer temperatures and lower light availability, leading to the dense growth of plant life depleting the amount of available oxygen and killing aquatic life—remains a major challenge for surface water bodies. Filtration mechanisms, with a wide range of applicability, capture common waterborne pathogens as small as 0.1–20.0 μm (bacteria, cysts, spores) and 0.001–0.100 μm (protein, viruses, endotoxins) through the process of microfiltration and ultrafiltration. This study follows the premise of using a designed water flow-through system, with meltblown nonwoven fabrics to measure its performance to capture water contaminant constituents of surface water contamination and eutrophication: total coliforms, nitrate, and orthophosphate. The achieved fabric filtration mechanism showed capture of total coliforms (59%), nitrate (51%), and orthophosphate (46%). The current study provides an alternative solution to more common and traditional water treatment technologies, such as chlorine and ozone disinfection, which (1) introduces disinfection or treatment byproducts and (2) cannot adapt to the permanent changing conditions and newer environmental challenges. Full article

(This article belongs to the Special Issue Lake Eutrophication: Causes, Monitoring and Restoration)

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17 pages, 6484 KiB

Open AccessArticle

A Unique Application Methodology for the Use of Phosphorus Inactivation Agents and Its Effect on Phosphorus Speciation in Lakes with Contrasting Mixing Regimes

by Hubert Kowalski, Jolanta Katarzyna Grochowska, Michał Łopata, Renata Augustyniak-Tunowska and Renata Tandyrak

Water 2023, 15(1), 67; https://doi.org/10.3390/w15010067 - 25 Dec 2022

Cited by 2 | Viewed by 1117

Abstract

The efficiencies of the restoration of two lakes of varied morphometries and trophic states—meromictic, hypertrophic Lake Klasztorne Małe, and dimictic, eutrophic Lake Klasztorne Duże—with the use of the phosphorus inactivation method with sequential application of iron and aluminum compounds have been compared. The [...] Read more.

The efficiencies of the restoration of two lakes of varied morphometries and trophic states—meromictic, hypertrophic Lake Klasztorne Małe, and dimictic, eutrophic Lake Klasztorne Duże—with the use of the phosphorus inactivation method with sequential application of iron and aluminum compounds have been compared. The total dose of the agents applied for Lake Klasztorne Małe was 38 tons of PAX 18 (aluminum polychloride) and 14 tons of PIX 111 (iron chloride), and for Lake Klasztorne Duże, it was 74 tons of PAX 18 and 46 tons of PIX 111. After the application of the compounds, better efficiency of phosphate removal from the surface water layers was obtained in the case of the dimictic, eutrophic Lake Klasztorne Duże. The use of two doses of compounds did not lead to complete precipitation of phosphates from the bottom water layers of either lake. It is noteworthy that in the case of both lakes, inhibition of the internal loading process was observed. The obtained results for the Klasztorne lakes showed that the use of two types of compounds makes it possible to reduce the cost of restoration, and moreover, the dosing of iron salts in the coastal areas of the lakes ensures a higher level of ecological safety. Full article

(This article belongs to the Special Issue Lake Eutrophication: Causes, Monitoring and Restoration)

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16 pages, 2555 KiB

Open AccessArticle

Water Quality Indicators in Three Surface Hydraulic Connection Conditions in Tropical Floodplain Lakes

by Miguel Ángel Salcedo, Allan Keith Cruz-Ramírez, Alberto J. Sánchez, Nicolás Álvarez-Pliego, Rosa Florido, Violeta Ruiz-Carrera and Sara Susana Morales-Cuetos

Water 2022, 14(23), 3931; https://doi.org/10.3390/w14233931 - 02 Dec 2022

Cited by 2 | Viewed by 1739

Abstract

Water quality indicators have been tied to natural or man-made surface hydraulic connection (SHC) conditions. Among these, temporally connected lakes (TCL) are hydraulic intermediates between isolated (IL) and permanently connected lakes (PCL). Therefore, the aim of this study is to answer if water [...] Read more.

Water quality indicators have been tied to natural or man-made surface hydraulic connection (SHC) conditions. Among these, temporally connected lakes (TCL) are hydraulic intermediates between isolated (IL) and permanently connected lakes (PCL). Therefore, the aim of this study is to answer if water quality indicators can estimate the possible overlap between the two opposed conditions of SHC (IL and PCL) with the intermediate one (TCL) in lakes with similar modifications in the water level regulation at the basin level. Among nine water variables sampled in six lakes with the three SHC conditions mentioned, chlorophyll a (Chl-a), Secchi disk (SD), and total phosphorus (TP) were identified as quality water indicators through principal component analysis. Furthermore, said indicators were used to measure their overlap and trophic state index deviations. The Chl-a, SD, and TP values in TCL showed a 0.72 overlap of PCL and IL. TP surplus measured in all the lakes was meaningful in urbanized ILs and lessened in a rural lake (PCL6) with submerged rooted macrophytes. The estimated overlap of trophic indicators between TCL, IL, and PCL in this study must be verified at a global representative scale for predictive and preventive use in the conservation of tropical coastal plain lakes. Full article

(This article belongs to the Special Issue Lake Eutrophication: Causes, Monitoring and Restoration)

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15 pages, 10431 KiB

Open AccessArticle

Reoligotrophication of a High-Nitrogen Reservoir with Phosphorus Removal and Implications for Management

by Xiaoyu Zhang, Lin Ding, Yue Liu, Haixia Liu, Boyu Xuan, Jian Zhao and Yuan Li

Water 2022, 14(17), 2629; https://doi.org/10.3390/w14172629 - 26 Aug 2022

Cited by 1 | Viewed by 1350

Abstract

Nitrogen pollution in the oligotrophic Chaihe Reservoir leads to reconsideration of whether nitrogen control is necessary. Does this mean that eutrophication control has the potential to create “cleaner lakes that are dirtier lakes?” The Chaihe Reservoir is a typical case of a water [...] Read more.

Nitrogen pollution in the oligotrophic Chaihe Reservoir leads to reconsideration of whether nitrogen control is necessary. Does this mean that eutrophication control has the potential to create “cleaner lakes that are dirtier lakes?” The Chaihe Reservoir is a typical case of a water body with high nitrogen and low algal populations. The relationship between the chlorophyll a (Chla) and nutrients (total nitrogen [TN] and total phosphorus [TP]) in the reservoir was analyzed using the filtering trajectory method (FTM). The results showed that the Chaihe Reservoir recovered to an oligotrophic state after the TP concentration greatly decreased, but it faces a new dilemma of nitrogen pollution. This provides further empirical support for the role of phosphorus in controlling the nitrogen cycle and fate in freshwater ecosystems. The contour plot and Chla-TN/TP diagram indicated that a higher TN/TP contributed to a reduction in Chla. The thresholds for TP and TN in the reservoir were proposed using the double probability method (DPM). It is recommended to remove nitrogen at the end of a drinking water supply system due to the nitrogen pollution of the Chaihe Reservoir. The TN threshold for buffering control provides a quantitative basis for implementing a nutrient management plan. Full article

(This article belongs to the Special Issue Lake Eutrophication: Causes, Monitoring and Restoration)

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14 pages, 1925 KiB

Open AccessArticle

Effect of Eutrophication Control Methods on the Generation of Greenhouse Carbon Gases in Sediment

by DAngelo A. Sandoval-Chacón and Anne M. Hansen

Water 2022, 14(11), 1705; https://doi.org/10.3390/w14111705 - 26 May 2022

Cited by 3 | Viewed by 2583

Abstract

The accumulation of nutrients (eutrophication) in water bodies generally produces increased concentrations of organic matter that eventually are deposited in sediment, and partially mineralized, generating greenhouse carbon gases (GHCG). The application of eutrophication control methods includes the application of phosphate adsorbing materials such [...] Read more.

The accumulation of nutrients (eutrophication) in water bodies generally produces increased concentrations of organic matter that eventually are deposited in sediment, and partially mineralized, generating greenhouse carbon gases (GHCG). The application of eutrophication control methods includes the application of phosphate adsorbing materials such as Phoslock (PHOS), and hypolimnetic oxygenation systems (HOS). We evaluated the generation of GHCG in sediment subject to these eutrophication control methods. Combined water and sediment samples from the Valle de Bravo reservoir in Mexico, were incubated in reactors, where the following eutrophication control methods were applied: HOS, PHOS, HOS + PHOS, and compared to a reactor without treatment (CONTROL). Redox potential (Eh), pH, redox-sensitive ions, and GHCG emissions were monitored, observing the following rates: CONTROL (15.6 mmol m⁻² d⁻¹) > HOS (12.8) > HOS + PHOS (11.0) > PHOS (9.7 mmol m⁻² d⁻¹), with the CONTROL rate within values determined from published sediment core data. The GHCG emissions increased with time as Eh decreased, and sulfate reduction increased. Application of eutrophication control methods in the Valle de Bravo reservoir, would most probably result in lower GHCG generation and emission rates. This is due to the repression of sulfate-reduction in water-sediment systems where HOS and PHOS were applied both individually and combined. Full article

(This article belongs to the Special Issue Lake Eutrophication: Causes, Monitoring and Restoration)

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12 pages, 825 KiB

Open AccessFeature PaperArticle

Increases in Picocyanobacteria Abundance in Agriculturally Eutrophic Pampean Lakes Inferred from Historical Records of Secchi Depth and Chlorophyll-a

by Horacio Ernesto Zagarese, Nadia R. Diovisalvi, María de los Ángeles González Sagrario, Irina Izaguirre, Paulina Fermani, Fernando Unrein, Manuel Castro Berman and Gonzalo Luis Pérez

Water 2022, 14(2), 159; https://doi.org/10.3390/w14020159 - 07 Jan 2022

Cited by 1 | Viewed by 1670

Abstract

Phytoplankton size structure has profound consequences on food-web organization and energy transfer. Presently, picocyanobacteria (size < 2 µm) represent a major fraction of the autotrophic plankton of Pampean lakes. Glyphosate is known to stimulate the development of picocyanobacteria capable of degrading the herbicide. [...] Read more.

Phytoplankton size structure has profound consequences on food-web organization and energy transfer. Presently, picocyanobacteria (size < 2 µm) represent a major fraction of the autotrophic plankton of Pampean lakes. Glyphosate is known to stimulate the development of picocyanobacteria capable of degrading the herbicide. Due to the worldwide adoption of glyphosate-resistant crops, herbicide usage has increased sharply since the mid-1990s. Unfortunately, there are very few studies (none for the Pampa region) reporting picocyanobacteria abundance before 2000. The proliferation of µm sized particles should decrease Secchi disc depth (ZSD). Therefore ZSD, conditional to chlorophyll-a, may serve as an indicator of picocyanobacteria abundance. We use generalized additive models (GAMs) to analyze a “validation” dataset consisting of 82 records of ZSD, chlorophyll-a, and picocyanobacteria abundance from two Pampean lakes surveys (2009 and 2015). In support of the hypothesis, ZSD was negatively related to picocyanobacteria after accounting for the effect of chlorophyll-a. We then fitted a “historical” dataset using hierarchical GAMs to compare ZSD conditional to chlorophyll-a, before and after 2000. We estimated that ZSD levels during 2000–2021 were, on average, only about half as deep as those during 1980–1999. We conclude that the adoption of glyphosate-resistant crops has stimulated outbreaks of picocyanobacteria populations, resulting in lower water transparency. Full article

(This article belongs to the Special Issue Lake Eutrophication: Causes, Monitoring and Restoration)

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17 pages, 2020 KiB

Open AccessFeature PaperArticle

Permanent Thermal and Chemical Stratification in a Restored Urban Meromictic Lake

by Renata Tandyrak, Jolanta Katarzyna Grochowska, Renata Augustyniak and Michał Łopata

Water 2021, 13(21), 2979; https://doi.org/10.3390/w13212979 - 22 Oct 2021

Cited by 3 | Viewed by 2206

Abstract

Meromictic lakes are unique aquatic ecosystems that occur extremely rarely. The phenomenon of meromixis can result from both natural and anthropogenic factors. The aim of this study was to analyse thermal and chemical stratification in a small, deep (6 ha, H max = [...] Read more.

Meromictic lakes are unique aquatic ecosystems that occur extremely rarely. The phenomenon of meromixis can result from both natural and anthropogenic factors. The aim of this study was to analyse thermal and chemical stratification in a small, deep (6 ha, H max = 24.5 m) lake. The evaluated lake had a typical summer thermal profile with a shallow epilimnion, a sharp thermocline, and a distinct monimolimnion layer in the hypolimnion, which was also maintained during circulation. The lake had a clinograde oxygen profile, with an oxygen deficit in the metalimnion and permanent anoxic conditions in the deeper layers, including during circulation. A redox zone was identified during summer stagnation. The monimolimnion formed a thermally isolated layer at a depth of around 15 m, and the chemocline was situated above the monimolimnion. In the chemocline, the EC gradient ranged from 61 to 77 μS·cm⁻¹ per meter of depth in the summer and from 90 to 130 μS·cm⁻¹ per meter of depth during circulation. EC was significantly correlated with Ca²⁺ concentration (r² = 0.549). Chemical stratification, particularly with regard to organic matter distribution, was observed in the chemocline. The monimolimnion severely limited nutrient internal loading. Full article

(This article belongs to the Special Issue Lake Eutrophication: Causes, Monitoring and Restoration)

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