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The aim of this study, conducted in accordance with both European Union and national legislation, was to evaluate the physicochemical conditions of the Rega River in northern Poland, where efforts are underway to restore its watershed for migratory fish. From 2018 to 2022, water temperature, dissolved oxygen (DO), pH, total suspended solids (TSS), conductivity, alkalinity, total hardness (TH), biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), nitrite nitrogen (NO2-N), ammonium nitrogen (NH4-N), and total phosphorus (TP) were measured at nine monitoring sites. The results showed that TSS and nitrite nitrogen (NO2-N) were the main factors threatening the suitability of the Rega River as a habitat for salmonid fishes. Additionally, maximum water temperatures occasionally exceeded the tolerance limits for these fishes. Seasonal variations in nitrogen and phosphorus forms, and the dependency of nitrogen forms on DO, indicated disruptions in natural biochemical processes due to surface runoff pollutants from the watershed. This includes fertilizer runoff from agricultural fields and municipal pollution from the towns through which the river flows. The findings underscore the need for continuous monitoring of Rega River waters to safeguard the habitat conditions required by environmentally sensitive fish species.

River pollution resulting from unregulated and improper water sewage management is a global issue of concern. The discharge of inadequately treated sewage into rivers and the sudden release of excessive quantities during heavy rainfall can result in significant fish mortality. This phenomenon has been observed repeatedly in the case of the Sąpólna River, NW Poland. Consequently, a decision was made to monitor the water quality at two key locations: the drainage channel that feeds into the river and downstream of the channel. Seventeen water quality indicators were measured, including temperature, pH, conductivity, total suspended solids (TSS), dissolved oxygen (DO), biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), total organic carbon (TOC), alkalinity, total hardness, total reactive phosphorus (TRP), total phosphorus (TP), nitrite-nitrogen (NO2−-N), nitrate-nitrogen (NO3−-N), total ammonia nitrogen (NH4-N), total organic nitrogen (TON), and total nitrogen (TN). It was determined that, at the location farthest from the drainage channel, water quality still falls short of meeting the specified standards. The primary factors leading to the degradation of water quality at this point were TSS, TRP, NO2−-N, and TN. It was concluded that the primary localized source of water pollution in the studied section of the Sąpólna River is the discharge from sewage treatment plants in Nowogard. Consequently, actions should be taken to address sewage quality and reduce discharge quantities. [ABSTRACT FROM AUTHOR]

The aim of the study was to analyze and assess the possibility of using a two-stage filtration system with ceramic membranes: a 3-tube module with 1.0 kDa cut-off (1st stage) and a one-tube module with 0.45 kDa cut-off (2nd stage) for treating effluent water from a juvenile African catfish aquaculture. The study revealed that during the 1st filtration stage of the effluent water, the highest degrees of retention were obtained with respect to: suspended solids SS (rejection coefficient RI=100%), turbidity (RI=99.40%), total iron (RI=89.20%), BOD5 (RI=76.0%), nitrite nitrogen (RI=62.30%), and CODCr (RI=41.74%). The 2nd filtration stage resulted in a lower reduction degree of the tested indicators in comparison to the 1st filtration stage. At the 2nd stage, the highest values of the rejection coefficient were noted in for the total iron content (RIV=100%), CODCr (RIV=59.52%; RV=64.28%, RVI=63.49%) and turbidity (RIV and RV = 45.0%, RVI=50.0%). The obtained results indicate that ceramic membranes (with 1.0 and 0.45 kDa cut-offs) may be used in recirculation aquaculture systems as one of the stages of effluent water treatment.

The objective of the study was to trace the variability of the hydrochemical conditions in three lakes of the West Pomeranian Voivodeship (Poland) - Starzyca, Maszewskie and Nowogardzkie in the annual cycle. The research was done in 2018-2019, and samples for analysis were collected 4 times a year. All analyses were performed applying standard methods. Such hydrochemical indices were determined as dissolved oxygen, chemical oxygen demand, content of orthophosphates, total phosphorus, nitrite, nitrate, ammonium, chlorophyll a and iron. The study showed that all lakes in the research cycle were characterised by a polymictic type of water mixing, and the trophic level, based on the adopted criteria, indicated advanced eutrophy, which may also be caused by anthropogenic pressure. Oxygen conditions characterised by deoxidation of the waters in the bottom layer in the spring and summer seasons, and clear oxygenation in the surface water layer (in Lake Maszewskie reaching even 188.5% in the spring) confirm the significant advancement of the eutrophication process. The supply of phosphorus and nitrogen in spring from pelagic waters in the waters of the examined lakes influences concentrations of chlorophyll a in the summer. The influence of "internal supply" (bottom waters and bottom sediments) on the amount of nutrients available for autotrophs is clearly visible in the analysed lakes - an increase in nitrogen and mineral phosphorus concentrations in relation to surface waters was observed in the bottom layer. [ABSTRACT FROM AUTHOR]

Highlights: What are the main findings? The high specific surface area of the biofilter media has a positive effect on nitrification. The smooth surface of the biofilter medium reduces the efficiency of nitrification. What is the implication of the main finding? Passive biofilter activation can be used in salmonid RAS. P and C concentrations do not limit nitrogen transformation processes. High-performance biofilters for water purification in recirculating aquaculture systems (RAS) ensure the safety of cultures of highly nutritious fish. As the most critical step in the functioning of biofilters is their activation, the objective of this study was to evaluate the suitability of commercial artificial media, namely RK Plast (BR-1), Mutag-BioChip30 (BR-2), and LevaPor (BR-3), for the passive activation of biofilters used in rainbow trout farming. Changes in NH4+-N, NO2−-N, NO3− -N, phosphorus, and carbon concentrations were analyzed. In the first period, an increase in NH4+-N concentration was recorded, before an increase in NO2−-N concentration (maximum concentrations ranged 0.728–1.290 and 0.982–5.198 mg N dm−3, respectively), followed by a reduction and stabilization to a level safe for the fish (both below 0.100 mg N dm−3). Concurrently, a steady increase in NO3−-N concentration was noted, with a maximum concentration between 6.521 and 7.326 mg N dm−3. Total phosphorus and total carbon ranged from 0.423 to 0.548 mg P dm−3, and from 43.8 to 45.2 mg C dm−3. The study confirmed the feasibility of using the tested artificial biofilter media for rainbow trout farming in RAS with passive biofilter activation. Biofilter activation efficiency was highest for the media with the highest specific surface area (BR-2 and BR-3). The removal of ammonium nitrogen and nitrite nitrogen was above 90%. Nitrogen biotransformation was not limited by phosphorus or carbon concentrations. [ABSTRACT FROM AUTHOR]

Abiotic and biotic bounty of riparian waters may be affected by inadequate maintenance works. Improper planning and execution of maintenance works cause changes to hydrological and hydrochemical condition of water in small rivers, affecting biocenose of riverbeds by modifying the taxonomic composition of organisms inhabiting the regulated river section. Five (5) rivers were subject to studies - Plonia, Mysla, Tywa, Rurzyca, and Wardynka (Odra river basin), which were monitored before and after maintenance works consisting in desilting, mowing and removal of aquatic plants. This study examined hydrological (mean depth and width of small rivers, speed and flow), physical and chemical parameter of water (temperature, pH, O2, N-NO3, N-NH4, P-PO4) before and after dredging of selected rivers. Obtained results and resulting statistical analysis demonstrated increase in hydrological indices - depth, width, speed and flow. Among other physical and chemical properties that significantly increased following completion of maintenance works, were O2 and NH4. NO3 concentration and temperature dropped, but not statistically significant. Changes in hydrological and hydrochemical properties of waters caused by maintenance works may affect biodiversity of the regulated river sections, including changes in composition of ichthyofauna species. [ABSTRACT FROM AUTHOR]

Copyright of Annual Set the Environment Protection / Rocznik Ochrona Środowiska is the property of Koszalin University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Following the culturing of post‐juvenile African catfish, wastewaters were purified using single and integrated processes. Iron coagulant (IC), aluminium coagulant (AC), lanthanum modified bentonite (LMB) and ceramic membranes (NF – nanofiltration) were each tested in single processes, while the combination of IC + NF and AC + NF were used in the integrated process tests. Among the single processes, membrane filtration was the most effective in purifying the aquaculture effluent. The total suspended solids (TSS) were removed entirely and there was a near‐complete removal of turbidity (99.2%), as well as effective removal of Al and Fe (80.8% and 67.4% respectively). Precipitating agents overall removed TSS most faithfully, from 37.5% removal with AC, through 50.2% with IC, to 62.3% with LMB. Using integrated processes, the highest removal efficacy was recorded for TSS (100%) and turbidity (99.7% – IC + NF; 99.9% – AC + NF). Additionally, integrated processes attained a 96.8%–98.4% removal of NO2‐‐N. This study confirms the possibility of using IC, AC and LMB in chemical purification of effluents from recirculating aquaculture systems (RAS). However, due to their low removal efficacy for nitrogen and phosphorus, it is preferable to use NF or integrated processes – membrane filtration combined with chemical precipitation, methods which proved to be most effective for water purification in RAS. [ABSTRACT FROM AUTHOR]

Small water bodies located in agricultural areas, so-called in-field ponds, are relicts of the last glaciation. They are characterized by high biodiversity, in addition to which they are astatic and subject to strong anthropopressure due to agricultural production, leading to their eutrophication. The main factors indicating water eutrophication include phosphorus and nitrogen compounds, but of significance are also heavy metals, trace elements and other macro- and microelements contained in water. The study was conducted in two small, in-field ponds in temperate climate. The aim of the undertaken study was to analyse and assess selected macro- and microelements in surface water of two in-field ponds and in groundwater under cultivated soil adjacent to the ponds. The content of the following elements was tested in water: Mg, Ca, Fe, Mn, Na, K, Zn. Among the analyzed macro- and microelements in the studied surface water and groundwater, the highest mean values were observed for calcium and chlorides, and the content of all the elements can be presented in the following order: Ca > Cl > Mg > Na > K > Fe > Mn > Zn. The highest levels of Ca, Cl, Mg and Na were recorded in groundwater under an intensively farmed field in Stare Czarnowo and in the in-field pond located in the middle of this field. Significant seasonal changes in the content of particular macro- and microelements were observed, with frequent peaks, primarily in the summer and autumn, resulting from the mobilization of internal resources from the bottom sediment or water flora. [ABSTRACT FROM AUTHOR]

Copyright of Ecological Engineering / Inżynieria Ekologiczna is the property of Polish Society of Ecological Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ecological Engineering / Inżynieria Ekologiczna is the property of Polish Society of Ecological Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nitrogen and phosphorus release during decomposition of Notothenia coriiceps (Richardson, 1844) fillets kept in seawater was examined in the laboratory. Amounts of N-NO, N-NO, N-NH, total inorganic nitrogen, total organic nitrogen (TON), total nitrogen (TN), total reactive phosphorus, total organic phosphorus (TOP), and total phosphorus (TP) released during a 5-day exposure were measured. The highest average release (from the standard 100 g fillet wet weight) was typical of TON and TN (2.574 and 2.703 mgN dm, respectively) as well as of TOP and TP (1.526 and 2.648 mgP dm, respectively). The release was observed to be most intense during the initial 120 min of decomposition. As shown by the accumulation rate coefficient, the highest rate of nutrient accumulation in water was typical of organic forms of N and P (0.827 and 1.329, respectively). Organic nitrogen and organic phosphorus accounted for 94 and 54 % of TN and TP release, respectively. In the experiment, nitrogen and phosphorus were released from the fish remains with leached chemicals, which may form important chemical cues for scavengers. [ABSTRACT FROM AUTHOR]

Background. Salmonid spermatozoa are characterised by a very short time of activity in the water, therefore sudden water pollution in the form of increased salinity on the spawning grounds may have a negative effect on the sperm motility parameters, thus affecting the subsequent egg fertilisation and, consequently, the number of hatched individuals of the species. The aim of this study was to determine the effect of water salinity on the motility parameters of spermatozoa of brook trout, Salvelinus fontinalis (Mitchill, 1814). Material and methods. Sperm motility was monitored with a camera (Basler A312fc) coupled with Nikon Eclipse 50i light microscope from the moment of their activation (contact with water) until the cessation of movement. The following water-salinity treatments were tested: 1.0‰, 3.0‰, 5.0‰, and 10.0‰. The motility parameters: VCL, VSL, VAP, ALH, BCF, LIN, STR, WOB, and MOT, were analysed with Computer Assisted Sperm Analysis (CASA). Results. The mean values of the studied motility parameters of the brook trout spermatozoa (obtained within 30 s), whose activation took place in the water of 0.35‰ salinity and in water of 1.0‰ and 3.0‰ salinity, did not differ significantly. The highest mean values of motility parameters were recorded for the water of 5.0‰ salinity. The 10.0‰ treatment caused a distinct decrease in the values of all the studied parameters. The percentage of MOT was the highest (37.5%) in the sample activated in the water used for fi sh rearing (0.35‰). In the remaining samples the MOT was lower, and in the water of 10.0‰ salinity it was only 9.1%. No spermatozoa movement of any kind was recorded in the 35th second of the experiment. Conclusion. The values of the motility parameters as well as the percentage of motile spermatozoa (MOT) in the semen decrease with increasing salinity of the water used for activation, and with increasing time of exposure. [ABSTRACT FROM AUTHOR]

Our paper presents a study on the middle reaches of the Ina River. Select physical and chemical indicators were analyzed in order to evaluate water quality. It was determined that the studied river was subjected to strong anthropopressure, and factors declassifying river water included CODCr, TP, general hardness, and alcalinity. A high level of biogenic elements was additionally increased by pollution discharged to the river in the proximity of a factory specializing in agricultural production and processing food and agricultural produce near the town of Stargard Szczecinski. The process of self-purification was noted, which can be considered as a factor modifying changes and dynamics of nitrogen and phosphorus in the studied river, leading to an internal enrichment with biogenic elements. Those processes were multi-directional as confirmed by PCA analysis, where component 1 accounted for just 36.7% of the total variance, and the total variance exceeding 90.0% was only noted for 7 components. [ABSTRACT FROM AUTHOR]

Effects of water salinity (3.0-9.0 PSU) on the duration and outcome of embryogenesis in the lesser sandeel ( Ammodytes tobianus (L.) as well as on survival, size, and malformation rate of the newly hatched larvae were followed, based on observations involving equipment consisting of a microscope and still and digital cameras. The images obtained and measurements of egg and larval dimensions were analyzed using the NIS elements Br. computer software package. The lowest salinity tested (3.0 PSU), similar to that in the inshore Baltic Sea waters native for the species studied, produced a lower fertilization rate and resulted in extended embryogenesis, reduced embryo survival, changes in the hatch size, and increased larval malformation rate. The high-end salinity (7.5-9.0 PSU), higher than that prevailing in the species's spawning grounds in the Baltic Sea, resulted - similarly to the low-end salinity - in disturbed development and growth of the embryos. [ABSTRACT FROM AUTHOR]

Wastewater generated as a result of the fish brining process has a very high contamination load. Application of appropriate technologies of wastewater treatment in order to reuse it in the production process once the NaCl content has been supplemented can provide an alternative to its costly recycling. The experiment included ultrafiltration tests conducted on waste brine originating from food processing industry. The results of physicochemical tests indicated very high reductions of fat content (100%) and turbidity (99.8%). Reductions were also revealed in the case of other indicators, i.e., chemical oxygen demand, biochemical oxygen demand, protein and histamine content: by 24.4, 35.2, 27.6 and 22.7%, respectively. Furthermore, it was reported that the obtained permeate retained its quality and microbiological stability. The studied ultrafiltration (UF) process can be successfully used for recirculation of brine in salted fish processing, and at the same time constitute an easily monitored critical control point in the hazard analysis and critical control point ( HACCP) system. Practical Applications Fish processing industry is characterized by very high water consumption for technological purposes and generates a considerable amount of wastewater burdened with organic matter and mineral compounds (mainly sodium chloride). Such wastewater is usually released to the common sewage system. An alternative solution would be to release it into a recirculation system. This solution can be made possible by membrane separation technologies. The application of the UF using ceramic membranes allows to obtain high-quality brine which can be successfully reused in the production process after the NaCl content has been replenished. Moreover, introduction of the UF technology meets the requirements of the HACCP system. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Water & Land Development is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mid-field natural ponds promote regional biodiversity, providing alternative habitats for many valuable animal species. The study's objective was to determine the most important abiotic factors, including hydrochemical and morphometric parameters, affecting fish occurrence in natural, small water bodies on agricultural lands. The studies were conducted in nine randomly selected water bodies located in Poland (the North European Plain). Eleven species of fish were recorded in the waterbodies, with the most abundant being cyprinids (mainly crucian carp). Canonical correspondence analysis (CCA) showed that an increase in oxygenation, temperature, amount of macrophytes, and K concentration and a decrease in the concentration of phosphates, electrical conductivity (EC), Mg, and Cl is associated with the most beneficial living conditions for the most frequently occurring species in the studied water bodies—crucian carp and tench. Aside from the hydrochemical parameters of water in the natural ponds, the number of fish correlates with the basin area and the pond area, maximum depth, area of the buffer zone surrounding the water bodies, and the number of macrophytes. This last factor also has a significant influence on the species' abundance in the water bodies. Fish occurrences in mid-field ponds and common knowledge on their important role in the environment require taking steps to provide fish protection. [ABSTRACT FROM AUTHOR]

Effective protection of lakes against degradation requires a detailed recognition of the factors leading to their eutrophication. This also pertains to small lakes, which constitute an important element of various ecosystems and are crucial for maintaining biodiversity. Therefore, the aim of the study is to determine the trophic state as well as the susceptibility to degradation of three small lakes in north-western Poland: Maszewo, Starzyca, and Nowogardzkie. This study analyzes the morphometric characteristics of the lakes, the impact of the catchment, their actual trophic state, and phosphorus levels. The analysis showed varying regeneration potentials of the lakes. Maszewo Lake is eutrophic-hypertrophic, nonresilient, strongly exposed to influence from the catchment, with phosphorus levels within the norm. Starzyca Lake is a eutrophic lake, not very resilient to the influence of the catchment, with excessive phosphorus levels. Nowogardzkie Lake is a eutrophic lake with moderate resilience to degradation, but with excessive phosphorus levels, which endangers the functioning of this aquatic ecosystem. In all the lakes, phosphorus supply was predominantly internal. Restoration of these lakes could be performed by completely cutting off the inflow of nutrients, as well as reclamation involving the deactivation of phosphorus (e.g., by precipitation) as well as the removal of the bottom sediments responsible for the internal supply of phosphorus. [ABSTRACT FROM AUTHOR]

Effects of total suspended solids in riverine water on embryonic development and larval survival, size, and malformation rate in pike (Esox luciusL.) were studied. Total suspended solids in concentrations even below 25 mg · dm[sup -3] (the generally accepted threshold level) were found to inhibit fish embryogenesis by affecting fertilisation (% fertilisation: untreated, filtered riverine water and tap water: 75; 91; 85, respectively), perivitelline space formation (perivitelline space %: untreated, filtered riverine water and tap water: 29.77; 33.07; 29.68, respectively), organogenesis, and hatching (in riverine water - hatching began at 95 D° and terminated at 140 D°; in filtered riverine water - hatching began at 110 D° and terminated at 150 D°). The total suspended solids were also found to affect the larval size: the larvae hatched in water containing suspended 0particulates were smaller than those hatched in clean water (larvae hatched from eggs incubated in riverine water total length 9.34mm, filtered water - 9.82 mm); the larval malformation rate was higher in the suspended solids-rich water (% malformed larvae - 9.0) than in clean water (% malformed larvae 7.0). [ABSTRACT FROM AUTHOR]