Long-term and seasonal trends of water parameters in the karst riverine catchment and general literature overview based on CiteSpace.

Although Europe is the continent with the highest proportion of karst areas, where hydrological systems are essential but extremely sensitive, data on the ecological status of karst riverine catchments are scarce. The aim of the present study was to assess the spatial and temporal (long-term and seasonal) variability of the physico-chemical and organic water parameters in the headwaters of the Krka River and its tributaries, as representatives of a typical karst ecosystem, situated in one of the largest karst areas in Europe, Dinarides in Croatia. It is affected in its upper reaches by improperly treated wastewaters, so anthropogenic influences and ecological status were estimated with the aim to present consequences of pollution exposure and importance of strict monitoring of such sensitive karst ecosystems worldwide.

Dynamics of drug contamination of the river-water in the rural, semirural and urban areas of the Mrežnica River in Croatia during COVID-19 pandemic (2020-2021).

Increased contamination of aquatic ecosystems with pharmaceuticals could have been expected due to the COVID-19 pandemic. Surface water from three domains (rural, semirural, urban) of the Mrežnica River (Croatia) was screened for 253 pharmaceuticals by SPE-UHPLC-MS/MS. At the beginning of the pandemic, the highest concentration of drugs (excluding veterinary) was detected at urban site (291.

Accumulation of metal(loid)s in the digestive gland of the mussel Unio crassus Philipsson, 1788: A reliable detection of historical freshwater contamination.

The possible influence of historical contamination of water/sediments on the metal(loid) bioaccumulation in the digestive gland of mussel Unio crassus Philipsson, 1788, from two differently contaminated sites at the Mrežnica River was studied in three seasons. The first data for this species on total/cytosolic concentrations of 27 (non)essential elements were obtained by HR ICP-MS. Higher bioaccumulation was observed at the historically contaminated site, with several nonessential elements (Bi, Cs, Pb, Sb, Tl, U) found in 5-6 times higher concentrations compared to the reference site.

Histochemical research of enzymes involved in cellular digestion in the digestive tract of tub gurnard, Chelidonichthys lucerna.

The tub gurnard Chelidonichthys lucerna (Linnaeus, 1758), Triglidae, is an opportunistic, demersal carnivorous fish. Data on the digestive enzymes of tub gurnard have not been reported in the literature. Therefore, the aim of this research was to investigate the distribution and intensity of alkaline phosphatase, acid phosphatase, non-specific esterase, and aminopeptidase in the digestive tract of tub gurnard.

Yesterday's contamination-A problem of today? The case study of discontinued historical contamination of the Mrežnica River (Croatia).

The remnants of historical industrial contamination can be detected in many aquatic ecosystems worldwide even at present time. Mrežnica is a river in Croatia that has been, for more than a hundred years, continually exposed to effluents of various industries, which have, in modern time, mostly ceased to operate. Our aim was to establish the level of current contamination and pollution of the Mrežnica river-water and sediments.

Metal-binding biomolecules in the liver of northern pike (Esox lucius Linnaeus, 1758): The first data for the family Esocidae.

Metal-handling strategies of various fish species are known to vary significantly in association with their intracellular metal behaviour. Thus, to better understand the possible consequences of increased metal exposure in fish it is important to perform comparative studies on metal-binding biomolecules in organs of different species. This study was the first of this kind on a liver of an esocid fish (northern pike, Esox lucius), and the gathered information were compared to fish belonging to three other families, Leuciscidae, Cyprinidae and Salmonidae.

The effect of different pollutants exposure on the pigment content of pigmented macrophage aggregates in the spleen of Vardar chub (Squalius vardarensis Karaman, 1928).

Pigmented macrophage aggregates (MAs) are known to change under influence of various factors, such as aging, season, starvation, and/or pollution. In this study, changes in the pigment content of the MAs in the spleen of Vardar chub (Squalius vardarensis, Karaman) (n = 129) collected in spring and autumn, from three rivers with different pollution impact was examined: Zletovska River (metals), Kriva River (metals and municipal wastewater), and Bregalnica River (municipal wastewater). Collected data revealed increased relative volume and number of MAs containing hemosiderin under the influence of metals, significant in autumn (p < .

Mining waste as a cause of increased bioaccumulation of highly toxic metals in liver and gills of Vardar chub (Squalius vardarensis Karaman, 1928).

Freshwater contamination with mining waste can result with high concentrations of toxic metals in the water and in fish organs. In North-Eastern Macedonia, several rivers (e.g.

Total and cytosolic concentrations of twenty metals/metalloids in the liver of brown trout Salmo trutta (Linnaeus, 1758) from the karstic Croatian river Krka.

Total and cytosolic concentrations of twenty metals/metalloids in the liver of brown trout Salmo trutta (Linnaeus, 1758) were studied in the period from April 2015 to May 2016 at two sampling sites on Croatian river Krka, to establish if river water contamination with metals/metalloids downstream of Knin town has influenced metal bioaccumulation in S. trutta liver. Differences were observed between two sites, with higher concentrations of several elements (Ag, As, Ca, Co, Na, Se, Sr, V) found downstream of Knin town, whereas few others (Cd, Cs, Mo, Tl) were, unexpectedly, increased at the Krka River spring.

Malondialdehyde concentrations in the intestine and gills of Vardar chub (Squalius vardarensis Karaman) as indicator of lipid peroxidation.

A lipid peroxidation product, malondialdehyde (MDA), was studied in Vardar chub (Squalius vardarensis Karaman) as an indicator of oxidative stress, using native fish from three rivers in northern Macedonia: the mining-impacted Zletovska and Kriva rivers and the agriculturally impacted Bregalnica River. MDA concentrations were measured in the intestine in the spring and autumn of 2012 and in the gills in autumn. The aims of the study were to establish the type of contamination which provokes a more pronounced MDA increase, as well as the organ which more reliably reflects the occurrence of oxidative stress.

Effects of heavy metal pollution on pigmented macrophages in kidney of Vardar chub (Squalius vardarensis Karaman).

Pollution with heavy metals may influence the immune system of fish, leading to impairment of their health or even increase their mortality. The fish kidney is one of the first fish organs to be affected by water contamination. Amounts of kidney macrophages (MACs), which are involved in fish immune response, as well as the qualitative and quantitative changes in the pigmented MACs in fish kidney, are used as biomarkers of pollution.

Histopathology investigation on the Vardar chub (Squalius vardarensis) populations captured from the rivers impacted by mining activities.

Many natural freshwater ecosystems, especially in the north eastern Macedonia, are polluted with heavy metals, which are released by active mines. Long-term exposure to high levels of dissolved metals might result in increased metal bioaccumulation in organs of aquatic organisms, and consequently might cause various sub-toxic and toxic effects. The aim of this study was to assess the health of Vardar chub (Squalius vardarensis) inhabiting mining impacted rivers Zletovska and Kriva, in comparison with chub from the reference Bregalnica River.

Pomphorhynchus laevis (Acanthocephala) from the Sava River basin: New insights into strain formation, mtDNA-like sequences and dynamics of infection.

Here we report the genetic variability and presence of mtDNA-like sequences of Pomphorhynchus laevis from the chub, Squalius cephalus, caught at the sampling sites along the Sava River and its tributary the Sutla River in Croatia. Sequences of the cytochrome c oxidase subunit 1 (COI) gene of the recovered P. laevis specimens were used for haplotype network construction and phylogenetic analysis.

Occurrence, characterization and antimicrobial susceptibility of Vibrio alginolyticus in the Eastern Adriatic Sea.

In 2007-2008, 162 samples (72 marine water samples, 90 swabs from the gills and skin) were collected from three European seabass fish farms in Eastern Adriatic. The aim of study was to determine the occurrence of Vibrio, to identify the isolated strains and to investigate their antimicrobial resistance. The comparison of the results obtained in spring and autumn periods indicated a higher Vibrio concentration in spring samplings.

Molecular characterisation and infection dynamics of Dentitruncus truttae from trout (Salmo trutta and Oncorhynchus mykiss) in Krka River, Croatia.

Dentitruncus truttae (Acanthocephala, Palaeacanthocephala) is an intestinal parasite of fish that can cause extensive damage to the host digestive tract, yet little is known about its epidemiology and genetic variability. It is a member of the Illiosentidae family with a worldwide distribution restricted to parts of southeast Europe. Its usual host is brown trout (Salmo trutta), but we report here the first detection in the intestine of rainbow trout (Oncorhynchus mykiss).

Assessment of general condition of fish inhabiting a moderately contaminated aquatic environment.

The assessment of general condition of fish in the moderately contaminated aquatic environment was performed on the European chub (Squalius cephalus) caught in September 2009 in the Sutla River in Croatia. Although increases of the contaminants in this river (trace and macro elements, bacteria), as well as physico-chemical changes (decreased oxygen saturation, increased conductivity), were still within the environmentally acceptable limits, their concurrent presence in the river water possibly could have induced stress in aquatic organisms. Several biometric parameters, metallothionein (MT), and total cytosolic protein concentrations in chub liver and gills were determined as indicators of chub condition.