Some heavy metals accumulation in tissues in Capoeta umbla (Heckel, 1843) from Uzuncayir Dam Lake (Tunceli, Turkey)

Microplastic pollution in two remote rivers of Türkiye

Microplastic pollution in aquatic ecosystems presents an emerging environmental threat that can have adverse effects on ecology, endanger aquatic species, and result in economic damage. Despite the numerous studies reporting the presence of microplastics in marine environments, research into their presence in freshwater systems or inland waters remains limited. This study aimed to assess the level of microplastic pollution transported by the Munzur and Pülümür Rivers and some small rivers that flow into the Uzunçayır dam lake, which is the confluence of the Munzur and Pülümür Rivers in Türkiye. Samples were collected from 23 stations, with the concentration of microplastics ranging from 0.01 MP/m³ at P-4 station to 28.21 MP/m³ at P-10, a station located near a city. Microplastics comprise four types: fiber, film, fragment, and glitter. The average size of microplastics was 1.46 ± 0.05 mm, with the average size of fibers, films, fragments, and glitter-type microplastics being 1.58 ± 0.07 mm, 1.23 ± 0.10 mm, 1.21 ± 0.11 mm, and 0.78 ± 0.16 mm, respectively. The most frequent polymers were polyethylene (31.8%), polystyrene (21.1%), and polypropylene (10.5%). Despite being considered remote and less populated rivers compared to other river systems in Türkiye, all sampling sites showed varying concentrations of microplastics.

Gill Histopathological Biomarkers in Fish Exposed to Trace Metals in the Todos os Santos Bay, Brazil

Histopathologies are widely recognized as biomarkers of environmental pollution. In this sense, we evaluated the putative relationship of gill histopathologies and distinct ecological impacts in two regions of Todos os Santos Bay (BTS), Brazil, the largest bay in Northeastern Brazil, South Atlantic. We compared the presence and concentration of metals (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, V, and Zn) in water, sediments, and gills and gill histopathologies of a demersal fish (Diapterus rhombeus) and a benthic fish (Ogcocephalus vespertilio). As expected, fish and sediment samples from historically contaminated areas (Aratu) showed more remarkable traces of metals than apparently low-impact areas (Jaguaripe). Likewise, the DTC (degree of tissue change) index and the volume densities were higher in fish caught in Aratu. In addition, the Diapterus rhombeus species showed more potential than Ogcocephalus vespertilio for risk assessment as it showed more responses to the environment reflected on more histopathologies. These data support the effectiveness of incorporating functional gill morphology to monitor impacts on estuarine biota that can be used as a reference to improve the management of ecosystems and prevent harm to human health.

Age- and Sex-Specific Bioaccumulation of Selected Metals in Freshwater Mussel (Unio elangatulus eucirrus Bourguignat, 1860) Populating from Keban Dam Lake (Elazig, Turkey)

In aquatic life, environmental chemicals are accumulated by mussels due to their sentinel nature and filter-feeding characteristics. Herein, the present study focused on assessing the concentrations of Cu, Zn, Mg, Mn, Fe, Cd, Pb, Ca, K, and Na levels in freshwater mussels (Unio elangatulus eucirrus) depending on sex and age. For all trace metals, some important differences of bioaccumulations were determined depending on ages and sex. In details, the results indicated that an important age-related accumulation of Mg, Cd, Ca, and K was in females and all trace elements, except Cu, Mg, and K levels in males (p < 0.05). No statistical differences were determined in mean concentrations of Cu, Zn, Mg, and Na. There are statistical differences in Mg, Mn, Fe, and Ca levels between females and males in four aged mussels (p < 0.05). Lead levels were under detectable limits. Overall, metal levels and their toxicity in freshwater mussels should be closely monitored for health of the environment, animals, and humans, since mussels and fish species fed on them are consumed highly in the research region and around.

Diversification of Dawkinsia filamentosa (Valenciennes, 1844) and their growth conditions by the impact of toxic metals in the river Tamiraparani

The concentration of toxic metals in water, sediment, and organs of species Dawkinsia filamentosa and its growth conditions were analyzed from the Tamiraparani river of Tamilnadu, India. The water quality preferred to examine the existence of metals, and the concentration of Pb, Cr and Cd expand the first time were found to be high in sediment, which was followed by water and the organs of the fish gill and liver. Even though, intakes of the toxic metals were highly accumulated in the gill instead of the liver. From that, the histological assessments of organ damages were observed significant variations in the study sites. Within the linear regression parameters for length-weight relationships of coefficient value r², 'a' value and 'b' value were showed the allometric growth rate and condition factor of 'K' was fittest. The phylogenetic tree analyses were showing analogy between the opposite groups of Clade III and Clade II showed that the species were closely correlated with the Puntius sp. of other species. And in Clade I was intimately related within the identical population of D. filamentosa as respectively. However, the comparison of metal concentrations of other Indian rivers and of other parts of the world specified that these metals are getting closer to the standard permissible limits. Altogether, the potential ecological risk factor was slightly increased at the sampling sites; therefore, we conclude that the metal contents might pollute the river. Throughout this research, the observed findings emphasize that fish species from the riverine ecosystem may useful for environmental management and genetic diversity.

Ecological risk assessment for different macrophytes and fish species in reservoirs using biota-sediment accumulation factors as a useful tool

Metal content was evaluated in the sediment, macrophytes and fish in the Medjuvršje reservoir (Western Serbia). Concentrations of 16 trace elements (Ag; Al; As; B; Ba; Cd; Co; Cr; Cu; Fe; Li; Mn; Ni; Pb; Sr; Zn) were analysed in the sediment, macrophytes and fish of an aquatic ecosystem. Five macrophyte species and three fish tissues (liver, muscle, gills) from five fish species (freshwater bream, common nase, Prussian carp, chub, wels catfish) were sampled and the metal content was analysed with ICP-OES. The sediment concentrations of Cu, Cd, and Zn exceeded the Canadian sediment quality guidelines while concentrations of Cr and Ni were above the Netherlands' target values. Bioaccumulation factors (BSAF) were calculated for analysed macrophytes and fish tissue. The BSAF had higher values for macrophytes for all investigated elements except for Cu and Zn; Cu had a higher value in the liver of the freshwater bream (0.823) and Zn had a higher value in the liver of freshwater bream (0.914) and chub (0.834) as well as in gills of Prussian carp (2.58) and chub (1.26). Potamogeton pectinatus, Ceratophylum demersum and the root of Phragmites communis showed higher accumulation of elements than Trapa natans and Potamogeton fluitans and the body of P. communis. The highest BSAF values for Ba, Mn, Sr and Ni were recorded in the gills. Cd and Cu had the highest BSAF values in the liver. Results confirmed that particular macrophyte and fish species could be a good indicator of reservoir water and sediment pollution.

Organochlorine pesticide, antibiotic and heavy metal residues in mussel, crayfish and fish species from a reservoir on the Euphrates River, Turkey

This study investigated the residues of 19 organochlorine pesticides, 37 antibiotics and 5 heavy metals in biota samples (one mussel species, one crayfish species, six wild fish species and one farmed fish species) from the Keban Dam Reservoir on the Euphrates River, Turkey. Among monitored OCPs, only p,p'-DDE was detected in biota samples. It was found only in mussel, fish muscle and fish gill samples. The highest concentration of p,p'-DDE (0.032 mg/kg ww) was determined in the gill of common carp, which was found to be below the maximum residue limit (MRL). Only sulfadimethoxine was detected among antibiotics in biota samples. Its maximum concentration (0.0044 mg/kg ww) did not exceed the MRL of 0.1 mg/kg. Sulfadimethoxine was found only in muscle and gill of common carp collected from site S6, where there are many rainbow trout cage farms. However, no detectable residue of sulfadimethoxine was found in farmed rainbow trout. The highest concentrations of As, Cd and Pb were detected in mussels, while the highest concentrations Cu and Zn were determined in crayfish. Metal concentrations in biota samples did not exceed the maximum permissible levels. According to these results, the consumption of biota samples from the Keban Dam Reservoir is safe for human health.

Temporal Changes in Concentrations of Some Trace Elements in Muscle Tissue of Crayfish, Astacus leptodactylus (Eschscholtz, 1823), from Keban Dam Lake

Crayfish (Astacus leptodactylus Eschscholtz, 1823) is the native crayfish species in Turkey. It was exported regularly to Western Europe. In this study, bioaccumulation and temporal trends of some trace elements (arsenic: As, cadmium: Cd, copper: Cu, mercury: Hg, lead: Pb, and zinc: Zn) in edible abdomen muscle of crayfish from Keban Dam Lake (Elazığ, Turkey) were investigated for the 2006–2012 period. Sequence of metal concentration levels was Zn > Cu > Hg > Pb > Cd > As in muscle tissues. The highest concentration of Zn (21.69 mg kg⁻¹) was detected in 2006, while the lowest (4.35 mg kg⁻¹) in 2009. In general, it was found that the concentrations of trace elements investigated were lower than the maximum permissible limits of the food regulations of the Ministry of Food, Agriculture, and Livestock (MFAL), the Turkish Food Codex and Commission Regulation (EC). If the crayfish selected for the study are recognized as bioindicators of environmental pollution, then it is possible to conclude that the changes in studied trace elements concentrations in the Keban Dam Lake are being steady.

Heavy metal concentrations in Mullus barbatus and Pagellus erythrinus in relation to body size, gender, and seasonality

Marine environments have been subjected to an increase in heavy metal pollution. Investigations were conducted in the bioaccumulation of heavy metals for both a benthic (Mullus barbatus) and a benthopelagic fish species (Pagellus erythrinus). The aim of this study was to examine the concentration levels of four metals in the body tissue of two fish species, in Pagasitikos Gulf in Greece, and to determine if metal concentration levels were affected by season, size, and species. Fish samples were collected monthly from September 2009 to August 2010. Chromium (Cr), Copper (Cu), Zinc (Zn), and Cadmium (Cd) concentrations were measured in muscle, gills, vertebral column, and in the "remaining fish sample." Statistical analysis pinpointed substantial differences in metal concentration levels between some size classes. Significant differences were observed between two fish species' tissues concerning Cu, Zn, and Cd concentrations. Cu and Zn concentrations varied amongst red mullet tissues as did Zn and Cd concentrations in common pandora. Ample variations were found seasonally in metal concentration levels; however, nonsignificant statistical differences were found among sexes.

Heavy metal and trace element bioaccumulation in target tissues of four edible fish species from the Danube River (Serbia)

Pikeperch (Sander lucioperca), European catfish (Silurus glanis), burbot (Lota lota), and common carp (Cyprinus carpio) were collected from the Danube River (Belgrade section, Serbia), and samples of liver, muscle, and gills were analyzed for Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Se, Sr, and Zn using inductively coupled plasma optical emission spectrometry (ICP-OES) to highlight the importance of species and tissue selection in monitoring research, contaminant studies, and human health research. The Kruskal-Wallis test revealed significant differences between fish species in regard to metal levels in liver, muscle, and gills. The principal component analysis (PCA) indicated that the studied fish species could be grouped on the basis of the level of analyzed elements in liver and gills. The Mann-Whitney test showed two subsets (one comprising two piscivorous species, pikeperch and catfish, and the other, two polyphagous species, burbot and carp) in regard to Cr and Hg levels in liver (higher levels in piscivorous species), as well as B, Fe, and Hg in gills (B and Fe with higher levels in polyphagous and Hg in piscivorous species), and As in muscle (higher levels in polyphagous species). Carp had distinctly higher levels of Cd, Cu, and Zn in liver in comparison to other three species. None of the elements exceeded the maximum acceptable concentrations (MAC). However, since Hg levels are close to the prescribed MAC levels, the consumption of these fishes can be potentially hazardous for humans.

Temporal variation of metals in water, sediment and tissues of the European chup (Squalius cephalus L.)

The aim of this study was to analyze seasonal variation of levels of Chromium (Cr), Manganese (Mn), Nickel (Ni), Copper (Cu), Zinc (Zn), Cadmium (Cd) and Lead (Pb) in water, sediment and tissues of Squalius cephalus (L., 1758) taken from five different stations chosen at Yamula Dam Lake (Kayseri, Turkey). Concentrations of metals were generally sorted as water < tissue < sediment. The highest concentration of metals in water was observed in the samples taken in the summer (Mn, 1.04 ± 0.15 mg L(-1); Ni, 0.42 ± 0.12 mg L(-1); Cu, 1.25 ± 0.88 mg L(-1); Zn, 3.61 ± 1.53 mg L(-1); Pb, 0.58 ± 0.09 mg L(-1)). While the highest Zn (24.85 ± 21.82 μg g(-1)) and Pb (10.89 ± 4.2 μg g(-1)) concentrations in sediment were observed in the winter samples, the highest Mn concentration (167.2 ± 99.37 μg g(-1)) was observed in the summer. Cd pollution was determined in sediment according to international criteria. The highest metal concentration in tissues was generally observed in the liver and the other tissues; following liver were gills and muscles. In liver tissues, while the highest accumulation of Zn (110.34 ± 13.1) and Mn (22.5 ± 14.85 μg g(-1)), which are essential for the body, were observed in the winter, Pb (22.58 ± 7.83 μg g(-1)) and Cd (11.77 ± 7.83 μg g(-1)), which are toxic, were found to be higher in the summer. Also, concentrations of Mn, Cd and Pb in muscle tissues were found to be above the limits permitted.