Bioaccumulation of heavy metals in blood and tissue of striped mullet in two Italian lakes

Risk assessment of As, Cd, Cr, and Pb via the consumption of seafood in Haikou

In order to mitigate the risk of excessive heavy metal intake, a study was conducted to assess the levels of arsenic (As), cadmium (Cd), chromium (Cr), and lead (Pb) contamination in 23 edible seafood species obtained from markets in Haikou. The findings were analyzed to evaluate the potential health hazards posed to the local population through consumption. The metals were detected via inductively coupled plasma mass spectrometry (ICP-MS) for quantification. The non-carcinogenic and carcinogenic health risks in humans were assessed via target hazard quotient (THQ), combined target hazard quotient (CTHQ), and target cancer risk (TR). The results indicated that the rank order based on the median metal concentration was As > Cd > Cr > Pb. THQ and CTHQ showed that nine seafood species posed a non-carcinogenic risk regarding from As and Cd consumption separately, or the four targeted metals ingestion together. TR assessment indicated that the InAs in all the species presented a carcinogenic risk to coastal residents. The Cd content in bivalves, algae, and several crustacean (Mantis Shrimp, Orchid Crab, Red spot Swimming Crab) and fish species (Japanese Scad, Pacific Saury), and Cr levels in most bivalve species (Razor Clams, White Clams, Fan Shells, Oysters, Blood Clams) presented a carcinogenic risk. The As, Cd, Pb, and Cr levels of seafood in Haikou were assessed species presented a potential health risk. Necessitating stricter risk should be management and detection capability and monitoring will be improved.

Effects of phytase enzyme supplementation on growth performance, intestinal morphology and metabolism in Nile tilapia (Oreochromis niloticus)

Phytase is crucial in enhancing the bioavailability and release of phosphorus and other nutrients bound to phytic acid, making them more bioavailable for animal absorption. This study was carried out to inspect the effect of supplementing low phosphorus (P) diet with di-calcium phosphate (DCP) and liquid phytase enzyme (LP), which contains 1500 FTU/kg, on growth performance, intestinal morphometry, proximate body chemical composition, blood profile, immunity status, liver mitochondrial enzyme activities, the expression response and economic returns of Nile tilapia (Oreochromis niloticus). Three triplicate groups of fish (initial weight 5.405 ± 0.045 g, N = 90) were fed on three different diets for 90 days. The first was a control diet with zero DCP; the second was a control diet supplemented with 0.71% DCP; the third was a control diet supplemented with 0.03% LP. The groups were designated as CG, DCP and LP, respectively. Results showed that LP induced considerable improvements (p < 0.05) in FBW, body weight gain, weight gain rate, specific growth rate, HIS, viscero-somatic index, spleen-somatic index, feed conversion ratio, blood parameters and the histomorphometry assessment of intestinal villi absorptive capacity, compared with the other groups. Also, whole-body protein and lipid contents pointedly (p < 0.05) increased by LP, compared with the DCP group. A positive response (p < 0.05) to the phytase enzyme was noted in complexes I, III and IV of the mitochondrial liver complex enzyme activity. Likewise, the relative gene expression levels of (GHr-1, IGF-1, FAS and LPL) were notably (p < 0.05) upregulated by phytase enzyme, associated with DCP and control groups. Further, phytase recorded the highest total return and profit percentage. It can be concluded that Nile tilapia benefits from using phytase enzyme 1500 FTU/kg at 0.03% without adding DCP in terms of good performance and profits.

Horse Whole Blood Trace Elements from Different Sicily Areas: Biomonitoring of Environmental Risk

Horses are excellent bioindicators for the assessment of environmental pollution. The aim of this study was to evaluate the levels and potential bioaccumulation of 28 mineral elements in 75 horse whole blood samples collected from five pollution-prone areas of Sicily, Italy. A direct mercury analyzer (DMA-80) was used for Hg determination, and an inductively coupled plasma mass spectrometer (ICP-MS) for all other elements. A one-way ANOVA test, followed by Bonferroni's multiple comparison for post hoc comparison, was applied to assess statistically significant differences between mineral elements and the five experimental groups. The levels of mineral elements in hay and concentrate were below the limits set by Regulation No. 744/2012. The mineral content of whole blood samples was slightly influenced by the region of origin of the horse. p values < 0.05 were statistically meaningful. However, the concentrations of mineral elements in horses' whole blood remained within reference ranges. In conclusion, the present study shows that the mineral content does not represent a toxicological risk for the analyzed horses. In addition, the study areas did not appear to show a high mineral element contamination.

Biotoxicity of Halide Perovskites in Mice

Halide perovskites are crystalline semiconductors with exceptional optoelectronic properties, rapidly developing toward large-scale applications. Lead (II) (Pb2+ ) is the core element used to prepare halide perovskites. Pb2+ can displace key 2+ elements, including calcium, zinc and iron, that regulate vital physiological functions. Sn2+ can replace Pb2+ within the perovskite structure and, if accidentally dispersed in the environment, it readily oxidizes to Sn4+ , which is compatible with physiological functions and thus potentially safe. The 3+ salt bismuth (III) (Bi3+ ) is also potentially safe for the same reason and useful to prepare double perovskites. Here, this work studies the biotoxicity of Pb, Sn, and Bi perovskites in mice for the first time. This work analyses histopathology and growth of mice directly exposed to perovskites and investigate the development of their offspring generation. This study provides the screening of organs and key physiological functions targeted by perovskite exposure to design specific studies in mammalians.

Toxic metals in Loggerhead sea turtles (Caretta caretta) stranded freshly dead along Sicilian coasts

BACKGROUND

The Loggerhead sea turtle (Caretta caretta) is a marine reptile belonging to a monophyletic group of chelonians. As these animals are long-lived, they have the ability to accumulate pollutants.

AIM

To collect epidemiological data on toxic metals in marine Loggerhead sea turtles.

MATERIALS AND METHODS

Forty Loggerhead sea turtles comprising 25 males and 15 females stranded freshly dead between 2013 and 2018 along the coasts of Sicily, Southern Italy, were examined for arsenic, cadmium, and lead accumulation in muscle and adipose tissues by means of a validated ICP-MS method. A modified K index as a growth condition factor, namely Fulton's K index, was used. Samples were tested in duplicate. A Wilcoxon rank sum test was carried out to evaluate metal contents differences between muscle and adipose tissues and between genders.

RESULTS

The Fulton's K index suggested a good body condition of the C. caretta recovered with mean values of 5.34 ± 3.40 (n = 40; ±SD). Detectable concentrations of lead were found in 70% of the samples analysed with mean values of 0.65 ± 1.67 mg/kg wet weight and 0.51 ± 1.29 mg/kg wet weight in muscle and adipose tissues, respectively. No significant differences in arsenic, cadmium, and lead were detected between genders. In addition, no significant correlation was found between modified K index and concentrations of arsenic, cadmium, and lead.

CLINICAL RELEVANCE

Findings on muscle and adipose tissues suggest chronic exposure of Caretta caretta to high concentrations of especially lead which might negatively affect health and welfare of these marine turtles although body condition was good.

Lead induced structural and functional damage and microbiota dysbiosis in the intestine of crucian carp (Carassius auratus)

Lead (Pb) is a hazardous pollutant in water environments that can cause significant damage to aquatic animals and humans. In this study, crucian carp (Carassius auratus) were exposed to waterborne Pb for 96 h; then, histopathological analysis, quantitative qPCR analysis, and 16S high-throughput sequencing were performed to explore the effects of Pb on intestinal bioaccumulation, structural damage, oxidative stress, immune response, and microbiota imbalance of C. auratus. After Pb exposure, the intestinal morphology was obviously damaged, including significantly increasing the thickness of the intestinal wall and the number of goblet cells and reducing the depth of intestinal crypts. Pb exposure reduced the mRNA expressions of Claudin-7 and villin-1 while significantly elevated the level of GST, GSH, CAT, IL-8, IL-10, IL-1, and TNF-α. Furthermore, 16S rRNA analysis showed that the Shannon and Simpson indices decreased at 48 h after Pb exposure, and the abundance of pathogenic bacteria (Erysipelotrichaceae, Weeksellaceae, and Vibrionaceae) increased after Pb exposure. In addition, the correlation network analysis found that Proteobacteria were negatively correlated with Firmicutes and positively correlated with Bacteroidetes. Functional prediction analysis of bacteria speculated that the change in intestinal microbiota led to the PPAR signaling pathway and peroxisome function of the intestine of crucian carp was increased, while the immune system and membrane transport function were decreased. Finally, canonical correlation analysis (CCA) found that there were correlations between the intestinal microbiota, morphology, antioxidant factors, and immune factors of crucian carp after Pb exposure. Taken together, our results demonstrated that intestinal flora dysbiosis, morphological disruption, oxidative stress, and immune injury are involved in the toxic damage of Pb exposure to the intestinal structure and function of crucian carp. Meanwhile, Pb exposure rapidly increased the abundance of pathogenic bacteria, leading to intestinal disorders, further aggravating the damage of Pb to intestinal structure and function. These findings provide us a basis for the link between gut microbiome changes and heavy metal toxicity, and gut microbiota can be used as biomarkers for the evaluation of heavy metal pollution in future.

Seasonal Biodistribution of Some Trace Elements (Cd, Pb, Cr, Hg) and "Blood Biomarkers" Response in Mugil cephalus (Linnaeus, 1758)

This study had a purpose to evaluate the seasonal biodistribution of some trace elements (cadmium, Cd; Lead, Pb; chrome, Cr; and mercury, Hg) in different tissues (muscle, gills, liver, stomach, and intestine) of striped mullet Mugil cephalus (Linnaeus, 1758) and the hematological and biochemical responses of this species to aquatic pollution by trace metals. For this purpose, 80 M. cephalus (20 for each season) were captured in three different stations of Faro Lake, Messina, Sicily. Biometric indices (weight, fork length, and total length) of each fish were registered. The physico-chemical parameters of the water of the study area were also measured, and the content of trace elements in water and sediment was determined. The hematological (white blood cell, WBC; red blood cell, RBC; hemoglobin concentration, Hb; hematocrit, Hct; mean corpuscular volume, MCV; mean corpuscular hemoglobin, MCH; mean corpuscular hemoglobin concentration, MCHC; thrombocytes count, TC), biochemical parameters (aspartate aminotransferase, AST; alanine aminotransferase, ALT; alkaline phosphatase, ALP; lactate dehydrogenase, LDH), and the seasonal concentration of the trace elements in the different tissues of M. cephalus were assessed. Our results showed a different biodistribution of the trace elements in M. cephalus and significant variations of the blood parameters in the different seasons. This research provides a valid contribute to environmental biomonitoring techniques useful in aquatic pollution control and water management. It also contributes to broadening the studies on the improvement of the health and sustainability of aquatic environments.

Effects of divalent mercury on myosin structure of large yellow croaker and its binding mechanism: Multi-spectroscopies and molecular docking

Heavy metals have long biological half-lives and are therefore a major threat to aquatic organisms, especially fish. Divalent mercury (Hg(II)) is an important form from a toxicological viewpoint. In this paper, we studied the interaction mechanism between large yellow croaker myosin and Hg(II) by multi-spectroscopies and molecular docking. Hg(II) had a positive effect on improving the elasticity of myosin gel, and the constant increase of charge would destroy the gel. Hg(II) caused myosin to aggregate, and the protein's apparent structure rapidly increased in length. The content of α-helix obviously decreased, β-turns and β-sheet increased. The myosin and Hg(II) quenching type was static quenching. Thermodynamic analysis suggested hydrogen bonding and van der Waals forces were the main forces for the combination. The molecular docking further confirmed the mechanism of action. This study provides a theoretical guidance for the preventions and control of marine heavy metals.

Transcriptomic Modulation Reveals the Specific Cellular Response in Chinese Sea Bass (Lateolabrax maculatus) Gills under Salinity Change and Alkalinity Stress

Salinity and alkalinity are among the important factors affecting the distribution, survival, growth and physiology of aquatic animals. Chinese sea bass (Lateolabrax maculatus) is an important aquaculture fish species in China that can widely adapt to diverse salinities from freshwater (FW) to seawater (SW) but moderately adapt to highly alkaline water (AW). In this study, juvenile L. maculatus were exposed to salinity change (SW to FW) and alkalinity stress (FW to AW). Coordinated transcriptomic responses in L. maculatus gills were investigated and based on the weighted gene co-expression network analysis (WGCNA), 8 and 11 stress-responsive modules (SRMs) were identified for salinity change and alkalinity stress, respectively, which revealed a cascade of cellular responses to oxidative and osmotic stress in L. maculatus gills. Specifically, four upregulated SRMs were enriched with induced differentially expressed genes (DEGs) for alkalinity stress, mainly corresponding to the functions of "extracellular matrix" and "anatomical structure", indicating a strong cellular response to alkaline water. Both "antioxidative activity" and "immune response" functions were enriched in the downregulated alkaline SRMs, which comprised inhibited alkaline specific DEGs, revealing the severely disrupted immune and antioxidative functions under alkalinity stress. These alkaline-specific responses were not revealed in the salinity change groups with only moderately inhibited osmoregulation and induced antioxidative response in L. maculatus gills. Therefore, the results revealed the diverse and correlated regulation of the cellular process and stress response in saline-alkaline water, which may have arisen through the functional divergence and adaptive recruitment of the co-expression genes and will provide vital insights for the development of L. maculatus cultivation in alkaline water.

Impact of Textile Industries on Surface Water Contamination by Sb and Other Potential Toxic Elements: A Case Study in Taihu Lake Basin, China

Contamination of industry-derived antimony (Sb) is currently of great concern. This study was conducted to identify the source of Sb together with other potential toxic elements (PTEs) in a typical industrial area in China and emphasize the contribution of Sb to ecological risk in the local aquatic environment. By investigating the distribution of nine PTEs in surface water in Wujiang County in dry and wet seasons, this study revealed that textile wastewater was the main source of Sb. The distribution of Sb (0.48~21.4 μg/L) showed the least seasonal variation among the nine elements. Factor analysis revealed that the factor that controlled Sb distribution is unique. In general, Sb was more concentrated in the southeastern part of the study area where there was a large number of textile industries, and was affected by the specific conductivity and total dissolved solids in water (p < 0.01). Sb concentration in 35.71% of samples collected from the drainage outlet exceeded the standard limit of 10 μg/L. Results from three pollution assessment methods suggested that >5% of the sampling sites were slightly too heavily polluted and Sb contributed the most. Therefore, it is necessary to strengthen the administrative supervision of local textile enterprises and elevate the local standard of textile wastewater emission.

Health risk assessment of some heavy metals detected in edible fishes of Gorgan Bay, Caspian Sea (Iran), for human

Just recently, heavy metals have been dramatically detected in aquatic animals, especially in fishes; hence, documented method to assess their health risks for humans who eat these contaminated fishes could be helpful. For the sake of this aim, the health risk assessment of four heavy metals including arsenic, cadmium, lead, and copper in three main edible fishes caught from Gorgan bay was studied. Mullet, roach, and common carp have been caught randomly in winter and spring of 2021 from three different fishing sites of Gorgan bay, including Miankaleh wetland, estuary of Qaresu River, and mouth of Chapaghli canal. Heavy metal measurement has been done with MOOPAM method, and risk assessment of fish consumption was assessed by estimated daily (EDI) and weekly intakes (EWI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TCR) indices. In this study, estimated daily intake (EDI) was much lower than the tolerable daily intake. Although TCR of cadmium within all fishes and arsenic in two fishes were more than acceptable value, THQ and HI values were less than one, and TCR of lead as well as copper was lower than the critical values, which suggests heavy metals of the Gorgan bay have no serious risks to consumer health.

Characteristics, Possible Origins, and Health Risk Assessment of Trace Elements in Surface Waters of the Han River Watershed, South Korea

To safeguard aquatic environments in and around the Han River watershed in South Korea, a multivariate statistical evaluation of trace elements, a trace element concentration analysis and source determination, and a human health risk assessment were conducted on 10 trace elements at 25 sites. The results demonstrated that the Han River watershed was mainly affected by anthropogenic activities (traffic/industrial activity). The range of concentrations was arranged in descending order: Fe (217.13 ± 301.03 µg/L) > Mn (102.36 ± 153.04 µg/L) > Zn (23.33 ± 79.63 µg/L) > Ba (29.05 ± 12.37 µg/L) > Ni (5.14 ± 11.57 µg/L) > Cu (3.80 ± 3.56 µg/L) > Pb (0.46 ± 0.52 µg/L) > Se (0.06 ± 0.04 µg/L) > Cd (0.01 ± 0.01 µg/L) > Ag (0.004 ± 0.013 µg/L). The hazard index values of trace elements in surface water for combined pathways (ingestion and dermal contact) were < 1.0 for both adults and children, indicating no possible human health hazards. The estimated total cancer risk did not exceed the acceptable limit (1 × 10^-4) for adults and children. The findings of this study provide data-driven guidelines for water environment policy decisions in the study area.

Risk Assessment of Essential and Toxic Elements in Freshwater Fish Species from Lakes near Black Sea, Bulgaria

The aims of this study were to measure the concentrations of selected toxic and essential elements in the muscle tissue of five common freshwater fish species ((roach (Rutilus rutilus), freshwater bream (Abramis brama), prussian carp (Carassius gibelio), crucian carp (Carassius carassius) and common carp (Cyprinus carpio)) from Lake Burgas and Lake Mandra (Bulgaria). In all samples the levels of Cd, Cr, Cu, Mn, Ni, Pb, Fe and Zn were under the maximum allowed concentrations for safe human consumption in Bulgaria and ranged as follows: Cd 0.02-0.05; Cr 0.03-0.06; Cu 0.11-0.20; Mn 0.05-0.71; Ni 0.06-0.11; Pb 0.15-0.27, Fe 1.68-5.86 and Zn 1.94-9.06 mg/kg wet weight. The concentration of As was under detection limit. An assessment of the human risk by calculation of the target hazard quotients (THQ), hazard index (HI) and target risk (TR) was performed. The target hazard quotient (THQ) for individual elements and HI for combined metals were lower than 1, indicating no health risk for consumers due to the intake of either individual or combined metals. The target risk for iAs, Pb and Ni was below 10^-6, indicating no carcinogenic risk. According to these results, the consumption of these freshwater fish species is safe for human health.

Pollution zoning on the southern shores of the Caspian Sea by measuring metals in Rutilus kutum tissue

The aim of this study was to bio monitor the status of heavy metals on the southern shores of the Caspian Sea by determining the concentration of these metals in the tissue of Rutilus kutum. Sampling of kidney tissue, liver, muscle, skin, and gonad of this fish was performed in 5 sites. Sampling was performed in Anzali, Kiashahr, Astara, Farahabad, and Bandar Torkaman from September 2017 to January 2018. In this study, the concentration of elements in different tissues was determined. Contamination zonation was determined by the concentration of metals in fish tissues. The highest amount of Pb accumulation (0.73 ppb) was determined in Astara and Anzali regions and in liver tissue. The highest amount of Cd (0.23 ppb) was reported in Astara region and in fish liver. Zoning showed that the concentration of most elements in the west of the Caspian Sea is higher than in the east; in other words, the west of the Caspian Sea is more polluted than the east. Existence of polluting sources such as ports, customs, agricultural lands, and tourism industry are important factors of pollution in these areas. Annual biological monitoring along with accurate identification of pollutant sources can help reduce this pollution, especially in the western part of the Caspian Sea. This study showed that the use of zoning technique in environmental studies as an effective management tool can be very useful in providing appropriate ways to identify and control sources and pollutants in the coast.

Fat rather than health - Ecotoxic responses of Bufo raddei to environmental heavy metal stress during the non-breeding season

The non-breeding season is a critical period for iteroparous animals to repair damage and store energy, which is crucial for future survival and reproductive success. However, it is unknown how animals allocate energy efficiently among reproduction, self-maintenance, and repair of oxidative damage caused by breeding during the non-breeding period, particularly under pollution. In the present study, the self-maintenance response and reproductive strategy of Bufo raddei to long-term environmental heavy metal stress was explored during the non-breeding season. Heavy metal enrichment level, organ coefficients, nutritional status, gonadal developmental level, oxidation level, and the immune status of B. raddei during the non-breeding season were tested, energy allocation preferences and energy consumption costs were analyzed. The results revealed significant heavy metal accumulation through biomagnification in the organs of B. raddei from the polluted area. Under long-term environmental heavy metal pollution, the energy investment by B. raddei for growth and energy storage was higher than that for health-maintenance during the early life cycle stage. The energy inputted for immune and antioxidant functions was significantly lower, and the energy inputted for self-maintenance during the early life stage was significantly higher than that during the late stage. B. raddei from a heavy metal polluted area spent more energy consumption cost on immunity and oxidative stress, but suffered higher oxidative stress and lower immune status. Moreover, the reproductive input of individuals in a heavy metal polluted area was generally low during the non-breeding season, and the energy input for reproduction limited the energy input for self-maintenance in females.

Exposure of African Catfish (Clarias gariepinus) to Lead and Zinc Modulates Membrane-Bound Transport Protein: A Plausible Effect on Na+/K+-ATPase Activity

The contamination of the aquatic ecosystem beyond tolerable limits may pose serious health challenges to its components. This study evaluated the toxic effects of a binary mixture of lead (Pb) and zinc (Zn) compounds on the activity of Na⁺/K⁺-ATPase in tissues of Clarias gariepinus in a controlled aquatic system. The study employed Box-Behnken Design (BBD) with 17 runs in which Pb and Zn concentrations were considered process variables in a time-dependent fashion. Metal exposure levels consisted of 0, 10 and 20% of 96 h-LC₅₀ of Pb (55.12 mg/L) and Zn (32.15 mg/L) for three weeks. Thereafter, membrane-bound Na⁺/K⁺-ATPase activity was assessed in gill, hepatic and renal tissues, and data generated from the BBD were used for the development of models. Three regression models were obtained, for gill, hepatic and renal Na⁺/K⁺-ATPase activities with exposure to metals differ significantly (p < 0.05) at R² > 90%, and no significant lack of fit (p > 0.05) was observed in each case. Congruent to the synergistic interactions observed between Pb and Zn in the study, the gill and hepatic Na⁺/K⁺-ATPase activities were significantly inhibited, whereas renal Na⁺/K⁺-ATPase activity was significantly stimulated (p < 0.05). The optimized models were considered reliable, as they were confirmed in the laboratory through accurate prediction of hepatic, renal and gill Na⁺/K⁺-ATPase activities with equivalences of 1.22 ± 0.17, 1.66 ± 0.07 and 3.50 ± 0.33 µmol p_i/min/mg protein (p < 0.05) respectively. It is hereby concluded that the synergistic interaction between Pb and Zn truncated the physiological function of Na^+/K⁺-ATPase activity in the respective tissues except for renal tissue of exposed C. gariepinus.

Nickel and cadmium tissue bioaccumulation and blood parameters in Chelon auratus and Mugil cephalus from Anzali free zone in the south Caspian Sea (Iran) and Faro Lake (Italy): A comparative analysis

BACKGROUND

Analysis of heavy metal concentrations in fish blood is a valuable tool in environmental pollution monitoring. Among different type of fish, detritivorous fish are a very good indicator for monitoring pollution and environmental stress, along with hematological studies, which are an important indicator in eco-toxicological and biological studies.

AIM

The aim of this study was to evaluate the influence of environment on bioaccumulation of Ni and Cd and on blood parameters in Chelon auratus and Mugil cephalus (a detritivorous fish which is widely distributed in the world) captured in Caspian Sea and Faro Lake.

METHODS

For the research blood and tissues samples were collected from 40 mullets (20 Mugil cephalus from Italy and 20 Chelon auratus from Iran) in 2019. The hematological (white blood cell, WBC; red blood cell, RBC; thrombocyte count, TC; hematocrit, Hct; hemoglobin concentration, Hb; mean corpuscular volume, MCV; mean corpuscular hemoglobin, MCH and mean corpuscular hemoglobin concentration, MCHC) and biochemical parameters (aspartate aminotransferase, AST; alanine aminotransferase, ALT; alkaline phosphatase, ALP; lactate dehydrogenase, LDH and creatine phosphokinase, CPK were assessed.

RESULTS

Although the concentration of Ni and Cd in the muscle of fish have no significant health risks and were low in both regions, the most elevated concentration was found in the liver of Caspian Sea mullet. In all cases, the results obtained for all biochemical and most hematological parameters of individual Faro Lake, were considerably lower than the Caspian Sea, demonstrating that habitats and environmental conditions affect the blood metabolites.

CONCLUSIONS

The results of this study show that these measurements can be used as criteria for the quantitative evaluation of fish /health and provide information on the extent of potential poisoning and the risks posed to the populations and fisheries.

Biochemical and reproductive biomarker analysis to study the consequences of heavy metal burden on health profile of male brick kiln workers

The present study aims to assess the effect of a heavy metal burden on general health, biochemical parameters, an antioxidant enzyme, and reproductive hormone parameters in adult male brick kiln workers from Pakistan. The study participants (n = 546) provided demographic data including general health as well as body mass index. Blood was collected to quantitatively assess hematological, biochemical, and reproductive hormone parameters as well as heavy metal concentrations using both atomic absorption spectroscopy (AAS) and particle-induced X-ray emission (PIXE). The data showed that 10% of the brick kiln workers were underweight and 10% obese (P = 0.059), with workers also reporting multiple health issues. Heavy metal concentrations utilizing AAS revealed significantly (p = 0.000) higher levels of cadmium, chromium, and nickel, while PIXE detected more than permissible levels of Si, P, S, Cl, K, Ca, Zn, Ti (p = 0.052), Mn (p = 0.017), Fe (p = 0.055), Co (p = 0.011), Ni (p = 0.045), and Cu (p = 0.003), in the blood of kiln workers. Moreover, a significant increase in platelet count (P = 0.010), a decrease in sodium dismutase levels (p = 0.006), a major increase in reactive oxygen species (p = 0.001), and a reduction in protein content (p = 0.013) were evident. A significant increase in cortisol levels (p = 0.000) among the workers group was also observed. The concentration of LH and FSH increased significantly (p = 0.000), while that of testosterone decreased (p = 0.000) in the worker group compared with controls. A significant inverse relationship was found between cortisol, LH (r =  - 0.380), and FSH (r =  - 0.946), while a positive correlation between cortisol and testosterone was also evident (r = 0.164). The study concludes that increased heavy metal burden in the blood of brick kiln workers exposes them to the development of general and reproductive health problems due to compromised antioxidant enzyme levels, increased oxidative stress conditions, and a disturbing reproductive axis.

Biomarker responses in perch (Perca fluviatilis) under multiple stress: Parasite co-infection and multicomponent metal mixture exposure

Parasitic infections may cause damage to the host immune system (i.e. fish), thereby endangering its health and weakening its responses to other types of stressors. Therefore, exposure to different kinds of natural or anthropogenic stressors can lead to unexpected toxicity outcomes in aquatic organisms. This study examined the haematological, genotoxic and cytotoxic effects of the co-infection with the protozoan parasite (Trichodina sp.) and the pathogenic oomycete (Saprolegnia parasitica) in Perca fluviatilis alone and in combination with chemical stress (environmentally-relevant aqueous concentrations of metal mixtures). Haematological analyses such as red cell and white cell indices revealed that chemical and biological stressors, used singly and in combination, exerted adverse effects on fish health. Changes in haematological indices induced by exposure to each of the above-mentioned stressors separately and by combined exposure to all of them suggested the multiple stress-induced inflammation process in the exposed fish. The cytogenetic damage inflicted by the S. parasitica and Trichodina sp. co-infection and multiple stress was revealed in fish erythrocytes. This information is expected to contribute to the elucidation of how multiple stressors impact on responses of haematic indices, geno- and cytotoxicity endpoints in P. fluviatilis. Assessment of the risk associated with multiple stressors is expected to prove valuable for the effective aquatic environment management (Løkke et al., 2013 and references therein).

Predicting the Trace Element Levels in Caspian Kutum (Rutilus kutum) from South of the Caspian Sea Based on Locality, Season and Fish Tissue

Elements are the shared result of the erosion of rocks in the catchment area and human activities. Nutritional habits, ecological needs, heavy metal concentrations in water and sediment, duration of fishing in the aquatic environment, fishing season, and physicochemical properties of water (salinity, pH, hardness, and temperature) are among the effective factors in the accumulation of heavy metals in various fish organs. In this study, 150 specimens of Rutilus kutum were collected from the southern shores of the Caspian Sea including Astara, Anzali, and Kiashahr in Guilan Province, Farahabad in Mazandaran Province, and Bandar Torkaman in Golestan Province from December 2018 through October 2019. It is possible to predict the metal concentrations using the variables such as fish tissue, sampling region, and season. Akaike information criterion (AIC) was used to select the best regression model. We used fish muscle tissue and Anzali sampling site which were considered reference variables in the regression model. For some elements, a better model is obtained by considering all variables (AIC criterion is its lowest value). The best model obtained for Cu, Mn, and Si was only with region (as a variable). The best model obtained for Sn and Sr only concerns the region and tissue variables. The best model obtained for Sb only related to tissue variable. Using these models, environmental monitoring becomes easier and cheaper. We suggest further studies to be carried out in the shortest possible time along with the least laboratory cost.

Acute Cd Toxicity, Metal Accumulation, and Ion Loss in Southern Catfish (Silurus meridionalis Chen)

The amounts of cadmium in multiple organs and the amounts of Na⁺ and Ca²⁺ in the carcass were measured in dead and surviving southern catfish exposed to different concentrations of Cd. The 96 h median lethal concentration was 6.85 mg/L. The Cd content and Cd accumulation rate were positively correlated with Cd exposure concentrations, and there were significant differences between dead and surviving individuals, indicating that both Cd content in tissues and Cd accumulation rates were correlated with mortality. Cd levels in the liver of dead fish were saturated. A lethal threshold for Cd concentration in the whole fish was obtained. Bioconcentration factors for Cd did not decrease with increasing exposure. Acute exposure to waterborne Cd caused a significant decrease in the ion content of the fish carcass. There was a significant difference between the Na⁺ content of the carcass of dead fish (34.54 μmol/g wet weight) and surviving fish (59.34 μmol/g wet weight), which was not the case with the Ca²⁺ content, indicating that the lethal toxicity of Cd was probably related to the decrease in Na⁺ content. Collectively, these results suggest that whole-fish Cd concentration and carcass Na⁺ content can be useful indicators of fish acutely exposed to Cd.

Effects of heavy metals speciations in sediments on their bioaccumulation in wild fish in rivers in Liuzhou-A typical karst catchment in southwest China

Although fish are widely confirmed to be susceptible to heavy metals (HMs) contamination in sediments, this bioconversion haven't been detailed. This is especially the case in karst areas, where HMs are less stably retained in the sediments and are more bioavailable. Therefore, we surveyed representative karst rivers in Liuzhou, China, in order to study the relationship between the speciations of seven HMs in the sediments with their bioaccumulation in wild fish. The results showed that the HMs in sediments are all below their permissible exposure limit (PEL), but Cd and Zn are significantly higher than soil basline. Most HMs are in residual fraction, while their exchangeable fractions are present in extremely low proportions. The concentration of Zn, Cr and Cd in some fish are above their maximum recommended limit (MRL). The concentrations of most of the HMs in the fish are significantly correlated with the levels in the sediments and given the higher correlation coefficients for their carbonate-bound phase, this phase can be seen to play a critical role in HMs bioconversion. However, the presence of this phase in low proportions enables other phases, especially oxidizable form, to play a greater role in HMs bioaccumulation. Apart from Do, HMs in the fish samples are significantly correlated with multiple environmental factors, demonstrating environmental fluctuations can manipulate HMs bioconversion from sediments; however, their significance depend heavily on the proportion of particular species. HMs in reducible and oxidizable fraction are more important in regulating, rather than promoting, their bioconversion during environmental fluctuations. Fluctuations in EC, TDS and pH can increase the impacts of HMs in carbonate-bound fraction on their bioconversion. Given the higher background values of EC and TDS and lower pH values during the monsoon period, careful attention should be paid to the increased bioconversion of HMs in karst rivers during this season.

Accumulation and risk assessment of heavy metals employing species sensitivity distributions in Linggi River, Negeri Sembilan, Malaysia

The constant increase of heavy metals into the aqueous environment has become a contemporary global issue of concern to government authorities and the public. The study assesses the concentration, distribution, and risk assessment of heavy metals in freshwater from the Linggi River, Negeri Sembilan, Malaysia. Species sensitivity distribution (SSD) was utilised to calculate the cumulative probability distribution of toxicity from heavy metals. The aquatic organism's toxicity data obtained from the ECOTOXicology knowledgebase (ECOTOX) was used to estimate the predictive non-effects concentration (PNEC). The decreasing sequence of hazardous concentration (HC₅) was manganese > aluminium > copper > lead > arsenic > cadmium > nickel > zinc > selenium, respectively. The highest heavy metal concentration was iron with a mean value of 45.77 μg L^-1, followed by manganese (14.41 μg L^-1) and aluminium (11.72 μg L^-1). The mean heavy metal pollution index (HPI) value in this study is 11.52, implying low-level heavy metal pollutions in Linggi River. The risk quotient (RQ) approaches were applied to assess the potential risk of heavy metals. The RQ shows a medium risk of aluminium (RQ_m = 0.1125) and zinc (RQ_m = 0.1262); a low risk of arsenic (RQ_m = 0.0122) and manganese (RQ_m = 0.0687); and a negligible risk of cadmium (RQ_m = 0.0085), copper (RQ_m = 0.0054), nickel (RQ_m = 0.0054), lead (RQ_m = 0.0016) and selenium (RQ_m = 0.0012). The output of this study produces comprehensive pollution risk, thus provides insights for the legislators regarding exposure management and mitigation.

Assessment of the Levels of Pollution and of Their Risks by Radioactivity and Trace Metals on Marine Edible Fish and Crustaceans at the Bay of Bengal (Chattogram, Bangladesh)

Marine environmental pollution is a longstanding global problem and has a particular impact on the Bay of Bengal. Effluent from different sources directly enters rivers of the region and eventually flows into the Bay of Bengal. This effluent may contain radioactive materials and trace metals and pose a serious threat to the coastal environment, in addition to aquatic ecosystems. Using gamma spectrometry and atomic absorption spectrometry, a comprehensive study was carried out on the radioactivity (226Ra, 232Th, 40K, and 137Cs) and trace metal (Cd, Pb, Zn, Cu, Ni, Fe, Mn, and Cr) concentrations, respectively, in fish and crustacean species collected from the coastal belt of the Bay of Bengal (Chattogram, Bangladesh). The analysis showed a noticeable increment in the levels of different radioactive pollutants in the marine samples, although the consumption of the studied fish and crustacean species should be considered safe for human health. Anthropogenic radionuclide (137Cs) was not detected in any sample. Furthermore, the metal concentrations of a small number of trace elements (Pb, Cd, Cr) were found to be higher in most of the samples, which indicates aquatic fauna are subject to pollution. The estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TR) were calculated and compared with the permissible safety limits. It was found that consuming the seafood from the Bay of Bengal may cause adverse health impacts if consumption and/or means of pollution are not controlled.

Toxicity and bioaccumulation of manganese and chromium in different organs of common carp (Cyprinus carpio) fish

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Heavy metals effects fishes when its concentration arises from its normal.

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Bioaccumulation of manganese and chromium was studied in Cyprinus carpio on hematological and biochemical parameters.

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In organ, bioaccumulation is highest in the gills followed by intestine > muscles > skin > bones.

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It is concluded that heavy metal can readily bio accumulate in the organs of fish.

The present research work was carried out to determine the bioaccumulation of manganese and chromium in the gills, intestine, muscles, skin and bones, as well as its acute toxicity and effects on hematological and biochemical parameters in Common carp (Cyprinus carpio). Adult carps were exposed for 96 h to manganese sulphate and chromium chloride solution, a sub lethal concentration was used in the experiment. Bioaccumulation was highest in the gills followed by intestine > muscles > skin > bones. The concentration of hematocrit (HCT) (37.3 ± 0.36), hemoglobin (HGB) (9.0 ± 0.04), Red Blood Cells (RBCs) (3.7 ± 0.025), mean corpuscular volume (MCV) (121.2 ± 0.36), mean corpuscular hemoglobin (MCH) (41.3 ± 0.3) and mean corpuscular hemoglobin concentration (MCHC) (41.06 ± 0.072) was significantly higher at 96 h (P < 0.01) after exposure to manganese and chromium, while the concentration of platelets (PLT) (16.8 ± 0.12) and white blood cells (WBCs) (62.7 ± 0.11) was lower at 96 h of exposure. Serum glutamic pyruvic transaminase (SGPT) (40.6 ± 0.4), Blood Urea (13 ± 0.1), serum triglycerides (231.21 ± 0.04), high-density lipoprotein (HDL) (39 ± 0.07), serum Alkaline PO₄ (242 ± 0.2), lactate dehydrogenase (LDH) (1239 ± 13.21), and serum Uric Acid (4.81 ± 0.33) were significantly higher (P < 0.01) at 96 h of exposure. The highest concentration of serum cholesterol (339 ± 0.09), serum reatinine (0.9 ± 0.01), low density lipid (240 ± 0.2) was observed at 24 h. Serum glutamic-oxaloacetic transaminase (SGOT) (19 ± 0.13), and serum albumin were at the highest level at 72 h (3.19 ± 0.07) (P < 0.01) post exposure.

Heavy metals pollution and health risk assessment in farmed scallops: Low level of Cd in coastal water could lead to high risk of seafood

Scallops are one of the most common bivalves, large-scale farmed in the coastal areas of China. Three species of scallops (Chlamys farreri, Argopecten irradians and Patinopecten yessoensis) from 10 samples sites along the Bohai Sea and the Yellow Sea were collected to investigate species-specific and tissues-specific bioaccumulation, spatial-temporal distribution and health risks for people. Cd must be paid attention since Cd concentrations in 96% of scallop samples exceeded standard with the highest Cd bioaccumulation potentials (BCF) >10,000 while those of the other metals were less than the corresponding limits except Zn with exceeding-limit percentage of 13%. The metal pollution index values showed that A. irradians could accumulate more metals than the other two species, and scallops in the Bohai Sea were polluted more seriously by heavy metals than in the Yellow Sea. The capacities of tissues in scallops to accumulate metals generally followed the order of digestive gland > gill > adductor muscle. However, Zn accumulated in gill was more than that in digestive gland and muscle. Adults and children would face the non-cancer risks because of the accumulation Cd in scallops based on health risk assessment. Cd was the major contributor of health risk to account for 85% of total hazard quotient and 48% of total cancer risk. Scallops could accumulate Cd rapidly from ambient environments to cause health risks according to the transplantation test. Moreover, the recommended maximum edible amounts of whole scallops were 127/63 g/week for adult/children on the basis of the provisional tolerance weekly intake. Humans are recommended to only consume adductor muscles for reducing health risks.

Spirulina platensis Alleviated the Hemotoxicity, Oxidative Damage and Histopathological Alterations of Hydroxychloroquine in Catfish (Clarias gariepinus)

The current study aims at evaluating the toxicity of hydroxychloroquine (HCQ) as a pharmaceutical residue in catfish (Clarias gariepinus) and the protective role of Spirulina platensis (SP). Four groups were used in this study: (1) a control group, (2) a group exposed to 3.16 mg/l of HCQ, (3) a group exposed to 3.16 mg/l of HCQ + 10 mg/l of SP, and (4) a group exposed to 3.16 mg/l of HCQ + 20 mg/l of SP for 15 days of exposure. The HCQ-treated group showed a significant decline in the hematological indices and glucose, total protein, and antioxidant levels in relation to the control group, whereas the HCQ-treated group showed a significant increase in the levels of creatinine, uric acid, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) as well as the percentage of poikilocytosis and nuclear abnormalities of RBCs in relation to the control group. The histopathological evaluation of the liver indicated dilation of the central vein, vacuolization, degeneration of hepatocytes and pyknotic nuclei, as well as reduction of glomeruli, dilation of Bowman's space, and degeneration of renal tubules in the kidney of the HCQ-treated group. Spirulina platensis (SP) rendered the hematological and biochemical indexes as well as antioxidant levels and the histological architecture to normal status in a dose-dependent manner. Accordingly, the current study recommends the use of SP to remedy the toxic effects of HCQ.

Bioaccumulation of trace elements in tissues of Indian oil sardine (Sardinella longiceps) from the northern United Arab Emirates

Small, partially enclosed gulfs are especially vulnerable to coastal pollution. The Arabian Gulf is a shallow, hypersaline, warm gulf with rising levels of pollution caused by rapid development and industrialization. We measured 19 trace elements in the gastrointestinal tract, liver and muscle of Indian oil sardines (Sardinella longiceps) from three sites from the United Arab Emirates in the southern Arabian Gulf. Concentrations of cadmium, chromium, copper and zinc exceeded international maximum permissible limits (MPL) in all three tissues in most sites. High concentrations in muscle raises concerns about the risk to humans, as muscles are widely consumed by humans. Discriminant Function Analysis showed that the three study sites (Sharjah, Ajman and Umm Al Quwain) could be discriminated based on a combination of elements. Improved monitoring of pollutants is needed to ascertain the concentration of pollutants in species at different trophic levels. We recommend better control measures to reduce the discharge of pollutants into this fragile marine ecosystem.

Study of occupational exposure to brick kiln emissions on heavy metal burden, biochemical profile, cortisol level and reproductive health risks among female workers at Rawat, Pakistan

The present study was planned to understand the heavy metal burden and its possible actions in blood of occupational females working at brick kilns at Rawat, Pakistan. A total of 232 women were included in the study, of which 114 presented control subjects. Apart from collection of demographic data, fertility indicators and body mass index (BMI), blood was collected from subjects that was later used for the determination of heavy metal concentrations using atomic absorption spectroscopy and haematological profile. Blood was centrifuged and plasma was obtained and stored at - 20° to study biochemical variables (sodium dismutase, peroxidase, reactive oxygen species, thiobarbituric acid reactive species, protein estimation), lipid profile and cortisol concentrations among the two groups. Analysis of heavy metal in blood showed elevated levels of cadmium (3.09 ± 0.01 μg/dl), chromium (4.20 ± 0.02 μg/dl) and nickel (5.59 ± 0.03 μg/dl) in worker's group as compared with control. Increased platelet count; decreased antioxidant enzyme and increased oxidants level; increased total cholesterol, low-density lipoprotein (LDL) and triglyceride (TG); decreased total protein and high-density lipoprotein (HDL); and increased cortisol levels were evident among workers as compared with the control group. The study concluded that occupational workers experience increased heavy metals burden in blood and, therefore, pose a risk to human health by causing reduction in antioxidant enzymes concentration and increase in stress conditions.

Trace elements exposure influences proximate body composition and antioxidant enzyme activities of the species tilapia and catfish in Burullus Lake-Egypt: human risk assessment for the consumers

The trace elements concentration in the fish estimates the contamination degree in the aquatic environment. These toxic trace elements are transported into the human through the consumption of polluted fish. This study estimated the effect of Cd, Hg, Pb, As, and Al on tilapia species and catfish Clarias gariepinus (six for each species of fish) inhabiting Burullus Lake-Egypt 30° 33'-31° 08' E and 30° 22'-31° 35' N. The highest Pb concentrations recorded in the muscle of C. gariepinus 2.29 ± 0.29 μg/g while S. galilaeus was estimated the lowest Hg concentration of 0.54 ± 0.02 μg/g which indicated the presence of contaminants exceeded the limits permitted by FAO/WHO and EC. The maximum mean carbohydrate, lipid, and protein recorded in O. niloticus 18.66, 16.33, and 58.16 mg/g, respectively; moisture in O. aureus 67.33%; and ash 16.41% in O. niloticus. The lowest amount of carbohydrate was recorded in the T. zillii 14.1 mg/g, lipid, and ash in C. gariepinus 11.65 mg/g and 3.375%, respectively. Protein and moisture in the S. galilaeus were 53.75 mg/g and 60.75%, respectively. The results recorded a marked insignificant (P > 0.05) decrease in CAT, GR, and GPx activity in O. niloticus. GSH and SOD activity was an insignificant (P > 0.05) decrease in C. gariepinus. The results concluded that the trace elements concentrations exceed the maximum permissible limits recommended in fish samples set by Egypt, FAO, WHO, and EC. The estimated weekly intake of all elements through consumption of studied fish species inhabiting Burullus Lake by a child (15 kg) in Egypt is well above the PTWI recommended by FAO/WHO, whereas it is well below the PTWI for human consumption by young people (40 kg) and adult person (70 kg), at least in respect of residual levels of studied elements excluding Cd and Hg. Thus, for consumer protection, these fish species are unsafe and have hazardous effects for children, and about youth and adult consumption, caution must be taken to consider individuals eating significant amounts of fish.

Combined effects of moderate hypoxia, pesticides and PCBs upon crucian carp fish, Carassius carassius, from a freshwater lake- in situ ecophysiological approach

Nowadays, depletion of oxygen or hypoxia has become a real concerning problem worldwide in freshwater, marine, and estuarine ecosystems and very often co-occurs with xenobiotics. Even though the acute and severe hypoxia is heavily studied in environment and laboratory studies, the in situ combined effects of these stressors on freshwater lake organisms are poorly understood. The current study sought to understand how the combined effects of moderate hypoxia, pesticides and PCBs affect the biochemistry, physiology and organ morphology of Carassius carassius, residing in the Lake Seferani, Dumrea region (Elbasan, Albania), a natural karst freshwater system declared as Nature Monument situated in central Albania. Crucian carp is used as a model organism, because of its residency and ecological relevance to the Lake, as well as for its amenability for the environmental toxicology studies. For this purpose, blood, liver and kidney samples of fish were processed for hematological, biochemical and histopathological analysis. We found a significant increase of blood glucose (GLU), cortisol levels, hematocrit (PCV) and hemoglobin (Hb) which clearly indicate the presence of stress in fish. Based on the histopathological evaluation and organ index results, liver and kidney organs displayed moderate-to-heavy histological-architecture changes. Our results provide a strong evidence that both, hypoxia and the presence of pesticides and PCB congeners found in Seferani Lake, put a heavy load on C. carassius energy metabolism and endocrine system, leading to an elevation of the biochemical and physiological parameters (hemoglobin level, hematocrit, glucose and cortisol), as well as the histopathological alterations. Additionally, in the presence of moderate hypoxia, the toxic effects of pesticides and PCBs on C. carassius are exacerbated. Further studies are needed to evaluate possible effects of pesticide and PCBs toxicity in human health, since crucian carp has an economic value for the population of the zone and it is used often as food sustenance. Elucidation of these kinds of responses can better improve our understanding of response of highly tolerant species, like Carassius carassius, to multiple stressors interactions, helping us to better predict and manage the consequences of the exposure of the freshwater biota to complex stressors in an environment that changes rapidly.

Toxic effects of waterborne ammonia exposure on hematological parameters, oxidative stress and stress indicators of juvenile hybrid grouper, Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀

Juvenile hybrid grouper, Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀ (mean weight: 26.5 ± 2.8 g, mean length: 11.8 ± 1.3 cm) were exposed to different, sub-lethal levels of waterborne ammonia (0, 1, 2, 4, and 8 mg NH₄⁺/L) for 2 weeks. We assessed the hematological parameters, antioxidant enzymes, and stress responses of juvenile hybrid grouper after 1 week and after 2 weeks. Hematological parameters such as hemoglobin and hematocrit levels, were significantly decreased by ammonia exposure. Plasma components such as the magnesium and total protein contents, and the glutamic oxaloacetic transaminase and glutamic pyruvic transaminase activities were significantly altered by ammonia exposure; however, no changes in the magnesium levels were detected. Antioxidant responses, such as superoxide dismutase and glutathione S-transferase activities, were also significantly affected by ammonia exposure. Stress indicator levels, i.e., plasma cholesterol and heat shock protein 70 levels, were significantly increased by ammonia exposure. The results of this study indicated that ammonia exposure has toxic effects on juvenile hybrid grouper and affects their hematological parameters, antioxidant enzymes, and stress responses.

Acanthocephalans parasites of two Characiformes fishes as bioindicators of cadmium contamination in two neotropical rivers in Brazil

Studies have demonstrated the role of acanthocephalan as environmental bioindicators. The dynamics in the parasite-host relationship that define the patterns of distribution of trace metals in parasites and, in its host, are extremely variable. In addition, the neotropical region, which is a major maintainer of the biodiversity of fish and parasites, remains little explored in this subject. Therefore, our objective was to analyze and compare the concentration of Cadmium (Cd) in the tissues of Prochilodus lineatus and Serrasalmus marginatus collected from Baía and Paraná rivers, as well as to assess the use of acanthocephalan as environmental bioindicators of pollution and their Cd bioaccumulation capacity. We collected 53 fish, 20 specimens of Prochilodus lineatus from Paraná River and 17 from Baía River, in addition to 16 specimens of Serrasalmus marginatus from Baía River, in September 2017 and March 2018. Tissues of the fish along with their parasites were subjected a Cd concentration analysis by Atomic Absorption Spectroscopy. The results revealed that the parasites had higher concentrations than all the tissues of S. marginatus, P. lineatus from Baía River and Paraná River. The high Cd concentrations in these parasites derived from their bioaccumulation capacity, because of the absorption of nutrients directly from the intestinal content of the fish through the tegument, as well as for the presence of Cd on the surface waters of Praná River floodplain. Besides that, the Coefficient of Spearman Rank Correlation showed that the infrapopulation size seems to affect Cd bioaccumulation in the parasites, smaller infrapopulations demonstrate a higher accumulation capacity compared to the larger ones. With that, we concluded that the two acanthocephalans species analyzed in this study have a good capacity for Cd accumulation, and can be used as accumulation indicators of trace-metal pollution. Accumulation indicators provide important information on the biological availability of pollutants.

Effect of pollution with lead, cupper, cadmium on gene expression pattern of liver GST and serum lysozymes in Nile tilapia (Oreochromis. niloticus)

Objective: This study was conducted to evaluate the influence of pollution with lead, copper, cadmium on the gene expression pattern of liver Glutathione-S-transferase and serum lysozyme in Nile tilapia (Oreochromis. niloticus). Design: Descriptive study. Fish: A Total of 120 Nile tilapia fish (Oreochromis niloticus) samples were collected from Lake Manzala, and drainage water at different localities. Procedures: Cd, Cu, and Pb concentrations residues within mid-dorsal muscle tissue, within gills, liver, and kidney were determined. Erythrocyte count, hemoglobin concentration, Packed Cell volume and other blood indices, as well as, total leukocyte count were measured. Biochemically, Alanine transaminase, Aspartate transaminase activities, total protein, creatinine, uric acid, lysozymes activity were estimated. GST gene expression was determined in the liver. Results: The results showed that Pb, Cu and Cd were bio accumulated at a higher level in the liver, kidney and gills of Nile tilapia fish (Oreochromis niloticus) from all sampling sites. The levels of the ALT and AST were increased, total protein and Albumin concentrations were decreased. Creatinine and uric acid were significantly (P≤ 0.05) increased in all groups (compared to the control group. Hematological parameters and lysozyme activity were decreased. Up regulation of the hepatic GST expression levels in Nile tilapia exposed to the heavy metals in comparison to the control value. Conclusion and clinical relevance: This study shows that lead, copper and cadmium were bio accumulated at higher concentration in liver, kidney, gills and muscles of Nile tilapia due to large industrial activities near locations of the sampling sites. Additionally, GST gene expression represents sensitive biomarker of aquatic pollution.

Environmental Investigations and Tissue Bioaccumulation of Heavy Metals in Grey Mullet from the Black Sea (Bulgaria) and the Ionian Sea (Italy)

The environmental monitoring of chemical toxicants has been a widely studied topic in the last few decades. The main aim of the present study was to determine the total concentration of nine elements (Cd, Cr, Pb, Ni, Al, Cu, Fe, Mn, and Zn) in the fish species grey mullet (M. cephalus) and in the coastal marine waters collected from various sampling points along the Black Sea (Bulgaria) and the Ionian Sea (Italy). Further, those results were applied to predict the pollution degree in those coastal marine environments. The fish samples were subject to acid digestion followed by appropriate analytical determination. The metal concentrations in marine water samples collected from the Black Sea (Bulgaria) and the Ionian Sea (Italy) were also analyzed. Unpaired Student's t-test and the one-way ANOVA were applied for the statistical analysis of the data. The statistical results revealed a significant variation (p < 0.0001) in the concentration of various fish tissues. The accumulation of toxic and essential elements differs significantly in grey mullet species caught from the Black Sea (Bulgaria) and the Ionian Sea (Italy). The results from this study may serve as a convenient approach during marine pollution programs set by both countries (Italy and Bulgaria).

Genotoxicity and oxidative damage in zebrafish (Danio rerio) after exposure to effluent from ethyl alcohol industry

In this research, the toxicological effect of untreated wastewater from of ethyl alcohol industry was evaluated on the zebrafish (Danio rerio) under experimental conditions. Fish were treated with zero, half, one and two percent of sewage effluent for 21 days. Toxic effects were monitored in liver by determining biochemical indicators, oxidative stress biomarkers, and the expression of genes involved in the detoxification. Results showed that Sod1, Gstp-1a, Gpx1a gene expressions were significantly increased in the hepatocytes after 21 days at 2.0% sewage exposure. Sewage exposure also significantly increased Gsr, Ces2 and Cyp1a, Mt1 and Mt2 gene expression in the hepatocytes of zebrafish as compared to the reference group (P < 0.01). Total cellular antioxidants, malondialdehyde (MDA) levels, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) activities in fish exposed to 1 and 2% of sewage were significantly higher than the control group (P < 0.01), whereas alanine aminotransferase (ALT) was only increased in fish exposed to 2% sewage (P < 0.01). A significant decrease in gamma-glutamyl-transferase (GGT) activity in fish exposed to 2% effluent was found (P < 0.01). Catalase (CAT) activity was increased in zebrafish exposed to all concentrations of effluent. The transcriptional analysis of the detoxification-related genes and the changes in the biochemical indicators evidenced that drainage of sewage effluents from the ethyl alcohol company is a serious threat to the health of aquatic animals in the Khorram-Rood River. These results will contribute to further study on the impact of sewage effluents of the alcohol industry on aquatic organisms.

Sentinel species for biomonitoring and biosurveillance of environmental heavy metals in Nigeria

Nigeria receives copious annual precipitation to nourish its forests and agriculture, it has an extensive river drainage system, and it possesses valuable mineral deposits that stimulate both commercial and artisan mining activities. The combination of these features complicates Nigeria's efforts to produce adequate amounts of healthy foods to support its population. Toxic heavy metals like lead, cadmium, and mercury, and toxic metalloids such as arsenic, are also present in its mineral deposits and they migrate gradually into the soil and water of Nigeria by natural means. However, mining activities can liberate higher levels of toxic metals, which adversely affect Nigerian ecosystems and its food chains. Thus, environmental pollution due to anthropogenic activities is a major public health concern in Nigeria. This review covers the importance of native Nigerian and African wild and cultivated plants along with livestock and wild animals as sentinel species to evaluate heavy metals as environmental stressors and the use of sentinel species for food safety monitoring and for predicting potential risks to human health.

The effect of foodborne sertraline on rainbow trout (Oncorhynchus mykiss)

The worldwide consumption of antidepressants is raising as well as their concentrations in the aquatic environment. This increases the risk of food chain contamination and bioaccumulation in aquatic biota. The aim of this study was to describe a potential risk of sertraline as a pollutant from water environment, wherein rainbow trout (Oncorhynchus mykiss) has been chosen as the test organism, because predatory fish are on the top of the food chain in the aquatic environment. The effects of foodborne sertraline were tested on rainbow trout during a 28-day toxicity test according to OECD 215 method. Sertraline was incorporated in commercial feed at a dose of 4.4 µg/kg (environmental concentration), 42 µg/kg and 400 µg/kg. The results confirmed that sertraline has a significant effect on fish behaviour, resulting in suppression of the escape reflex and increased resistance to stress. Moreover, increased Fultońs condition factor was found in fish fed with the highest concentration of sertraline. Haematological analysis revealed a statistically significant increase in the number of neutrophilic bands and neutrophil/lymphocyte ratio, and decreased number of lymphocytes. The results of biochemical examination showed a statistically significant decrease in ammonia and lactate concentrations and histological examination revealed changes in gills and caudal kidney. Although sertraline reduces stress in fish, the decline in nonspecific immunity is a risk to fish population stability.

Bioaccumulation of lead nitrate in tissues and its effects on hematological and biochemical parameters of Clarias gariepinus

Clarias gariepinus, weighing 119.18 ± 5.21 g, were exposed to 0%, 20%, 40%, and 60% of the LC₅₀ lead nitrate, Pb(NO₃)₂, which represents the following treatments 0 (control), 16, 32, and 48 mg/l, respectively, for a period of 10 and 20 days. The results showed that the bioaccumulation of Pb(NO₃)₂ in gills were significantly increased (p < 0.05) after 10 days having 0.17 ± 0.07, 5.05 ± 1.04, 6.01 ± 0.82, and 9.61 ± 1.76 mg/100 g wet weight, respectively, for the treatments. However, after 20 days these values increased ((0.17 ± 0.07, 4.34 ± 1.27, 10.83 ± 0.97, and 19.18 ± 2.40 mg/100 g) for 0%, 20%, 40%, and 60% of LC₅₀ Pb(NO₃)₂ respectively. There was an increase with each increasing concentration level of Pb(NO₃)₂ as compared with that of the control group. The accumulation of Pb(NO₃)₂ in the liver, showed a significant increase (p < 0.05) with the increasing period of exposed and Pb concentration with LC₅₀ values ranging between 3.32 ± 0.91 and 4.42 ± 0.78 after 10 days as compared with that of the control group 0.08 ± 0.02 mg/100 g wet weight. Although white muscles and skin displayed lower values of bioaccumulation than gills and liver after 10 days, after 20 days the results were slightly more increased in the white muscles than in the skin. However, the observed pattern of increase was the same compared to that of the control group. Therefore, hematological parameters, such as red blood cells (RBCs), hemoglobin (Hb), and hematocrit (Hct) showed significant (p < 0.05) concentration-dependent decreases in fish exposed to Pb(NO₃)₂ during both periods. However, the values of white blood cells (WBCs) showed a significant reduction when levels of Pb concentration increased. Hepatic enzyme activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) displayed a significant increase with increasing concentrations and exposure time.

Antagonistic effects in zebrafish (Danio rerio) behavior and oxidative stress induced by toxic metals and deltamethrin acute exposure

In natural environments, the aquatic organisms are exposed to complex mixtures of chemicals which may originate from natural sources or from anthropogenic activities. In this context, the aim of the study was to assess the potential effects that might occur when aquatic organisms are simultaneously exposed to multiple chemicals. For that, we have studied the acute effects of cadmium (0.2 μg L^-1), nickel (10 μg L^-1) and deltamethrin (2 μg L^-1) as individual toxicants and as mixture on the behavioral responses, oxidative stress (SOD and GPx), body electrolytes and trace metals profiles of zebrafish (Danio rerio). So far the scientific literature did not report about the combined effects of pesticides and toxic metals on zebrafish behavior using a 3D tracking system. Compared with other studies, in the present paper we investigated the acute effects of two heavy metals associated with a pesticide on zebrafish, in the range of environmentally relevant concentrations. Thus, the environmental concentrations of cadmium and nickel in three rivers affected by urban activities and one river with protected areas as background control were measured. The observations that resulted in our study demonstrated that deltamethrin toxicity was significantly decreased in some of the behavioral variables and oxidative stress when combined with CdNi mixture. Consequently, our study supports previous works concerning the combined toxicity of environmental chemicals since their simultaneous presence in the aqueous environment may lead to higher or lower toxicological effects on biota than those reported from a single pollutant. Therefore, the evaluation of toxic effects of a single contaminant does not offer a realistic estimate of its impact against aqueous ecosystems. This study also supports the idea that the interactions between different chemical compounds which do not exceed the maximum permitted limits in environment may have benefits for aquatic life forms or be more toxic.

Effects of mustard oil cake on liver proteins of Channa punctatus (Bloch)

Mustard oil cake is a biofertilizer widely used in agriculture and fish cultivation almost in all South East Asian Countries including India. The study was carried out to observe the effects of this biofertilizer on the liver proteins of Channa punctatus. At sublethal concentration (0.42 g/L ), fishes were exposed for a prolonged period of 35 days and amount of total liver protein (TLP) was measured. The investigation showed a low rate of liver protein synthesis in treated fish after 4 days of exposure. An increase in the amount of protein was observed between the 7^th and 35^th day. But such increment was below the amount of TLP of control fish, indicating physiological stress in the treated fish.

Response of vanadium bioaccumulation in tissues of Mugil cephalus (Linnaeus 1758)

Vanadium accumulation levels in different tissues (muscle and organs) of the striped mullet Mugil cephalus (Linnaeus, 1758) and possible relationships with blood parameters were evaluated in a Natural Protected Area (Lake Faro, Sicily, Italy), during the winter of 2017. Hematological parameters (red blood cell, RBC; white blood cell, WBC; hemoglobin concentration, Hb; hematocrit, Hct; mean corpuscular volume, MCV; mean corpuscular hemoglobin, MCH; mean corpuscular hemoglobin concentration, MCHC; thrombocytes, TC), biometric indices (weight, total and fork length), and vanadium levels in muscles and organs (gills, liver, stomach and intestine) were determined. Statistical analyses showed significant differences in concentrations of vanadium of the analyzed tissue of M. cephalus and a positive relationship between vanadium concentration in the liver and some hematological parameters (RBC, Hb and Hct) and biometric indices. Our results underline the importance of fish blood parameters as sensitive indicators of toxic impact of environmental factors such as metals. This study, focusing on an ongoing topic, represents a valuable contribution to research concerning the monitoring and prevention of vanadium pollution in aquatic organisms and environments.

Cytotoxic and genotoxic effects of arsenic on erythrocytes of Oryzias latipes: Bioremediation using Spirulina platensis

BACKGROUND

Exposure to the environmental pollutants poses a serious threat to aquatic organism. The arsenic exposure in fish increases the risk of developing serious alterations from embryo to adult.

OBJECTIVES

The present investigation was done to study the toxic effects of heavy metal arsenic [As(III)] on medaka (Oryzias latipes). Morphological alterations, apoptosis, nuclear abnormalities, and genotoxic biomarkers in erythrocytes were used to determine the stress caused by arsenic (As) exposure.

METHODS

Medaka was exposed to As for 15 days at two toxic sublethal concentrations (7 ppm and 10 ppm) in combination with Spirulina platensis (SP) treatment as antioxidant algae at 200 mg/L.

RESULTS

Results were consistent with a previous study results on tilapia. Exposure of medaka to As resulted in a dose-dependent increase in most the biomarkers used in the current study. Fish exposed to10 ppm As showed highest level of DNA damage. For the first time to our knowledge, using SP to counter the As toxicity in medaka, DNA damage restored to control levels.

CONCLUSION

Accordingly, those results suggests that SP can protect medaka in aquaculture against As-induced damage by its ability as reactive oxygen species (ROS) reducer, antioxidant role, and DNA damage scavenger.

Ultrastructural changes in fin epithelium of Channa punctatus (Bloch) exposed to mercuric chloride: sem study

Fish skin is in direct contact with water and forms the first line of defense against pathogens and toxicants present in the surrounding water. The effect of mercuric chloride (HgCl₂) on surface architecture of the epidermis of caudal fin of an air breathing fish, Channa punctatus was examined by scanning electron microscopy (SEM) and revealed the presence of microridges that formed intricate, maze-like patterns. The exposed fish showed significant alterations including disorganization of microridge pattern and increase in number as well as enlargement of mucus cell openings. These findings exhibited concentration- and time- dependent alterations in fin epithelium. Data demonstrated that fin epithelium of fish may be successfully employed as a bioindicator of water pollution.

Multidisciplinary haematology as prognostic device in environmental and xenobiotic stress-induced response in fish

The variations of haematological parameters hematocrit, hemoglobin concentration, leukocyte and erythrocyte count have been used as pollution and physiological indicators of organic dysfunction in both environmental and aquaculture studies. These parameters are commonly applied as prognostic and diagnostic tools in fish health status. However, there are both extrinsic and intrinsic factors to consider when performing a blood test, because a major limitation for field researchers is that the "rules" for animal or human haematology do not always apply to wildlife. The main objective of this review is to show how some environmental and xenobiotic factors are capable to modulating the haematic cells. Visualizing the strengths and limitations of a haematological analysis in the health assessment of wild and culture fish. Finally, we point out the importance of the use of mitochondrial activities as part of haematological evaluations associated to environment or aquaculture stress.

Sub-lethal effects of dimethoate alone and in combination with cadmium on biochemical parameters in freshwater snail, Galba truncatula

The objective of the present study was to evaluate the influence of the organophosphorus pesticide dimethoate and cadmium on biochemical parameters of a freshwater snail, Galba truncatula, in laboratory conditions. In 14 days, snails were exposed to 0, 100, 200, and 400 μg L^-1 of dimethoate and 0.0 and 1000 μg L^-1 of cadmium chloride. The results evidenced that dimethoate induces oxidative stress and alters biochemical parameters in freshwater snails. Cadmium also induced significant changes in biochemical parameters. The combination of the dimethoate and cadmium markedly increased the effects on G. truncatula. Dimethoate and cadmium mixture caused a decrease in Acetylcholinesterase (AChE), and Glucose-6-phosphate dehydrogenase (G6PDH) activities, glycogen, and total antioxidant capacity (TAN) levels, and increased aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), glutathione peroxidase (GPx), and catalase (CAT) activities, and malondialdehyde (MDA) level in exposed snails. The increased toxicity and bioaccumulation of cadmium after the exposure to the highest concentration of dimethoate indicates a synergistic effect leading to a reduced performance of the detoxification system in the snail. Dimethoate contributed to the bioconcentration of cadmium in snails and increased its toxic effects evidenced in biomarkers of oxidative stress and cell damage.

Elucidation of the microbial diversity in rivers in south-west Victoria, Australia impacted by rural agricultural contamination (dairy farming)

We assessed the water quality of south-west Victorian rivers impacted by the dairy industry using traditional water quality assessment together with culture-dependent (colilert/enterolert) and also culture-independent (next generation sequencing) microbial methods. The aim of the study was to identify relationships/associations between dairy farming intensity and water contamination. Water samples with high total and faecal coliforms (>1000 MPN cfu/100 ml), and with high nitrogen levels (TN) were observed in zones with a high proportion of dairy farming. Members of the genus Nitrospira, Rhodobacter and Rhodoplanes were predominant in such high cattle density zones. Samples from sites in zones with lower dairy farming activities registered faecal coliform numbers within the permissible limits (<1000 MPN cfu/100 ml) and showed the presence of a wide variety of microorganisms. However, no bacterial pathogens were found in the river waters regardless of the proportion of cattle. The data suggests that using the spatially weighted proportion of land used for dairy farming is a useful way to target at-risk sub-catchments across south west Victoria; further work is required to confirm that this approach is applicable in other regions.

Microplastics in the marine environment: Current trends in environmental pollution and mechanisms of toxicological profile

The global plastics production has increased from 1.5 million tons in the 1950s to 335 million tons in 2016, with plastics discharged into virtually all components of the environment. Plastics rarely biodegrade but through different processes they fragment into microplastics and nanoplastics, which have been reported as ubiquitous pollutants in all marine environments worldwide. This study is a review of trend in marine plastic pollution with focus on the current toxicological consequences. Microplastics are capable of absorbing organic contaminants, metals and pathogens from the environment into organisms. This exacerbates its toxicological profile as they interact to induced greater toxic effects. Early studies focused on the accumulation of plastics in the marine environment, entanglement of and ingestions by marine vertebrates, with seabirds used as bioindicators. Entanglement in plastic debris increases asphyxiation through drowning, restrict feeding but increases starvation, skin abrasions and skeletal injuries. Plastic ingestion causes blockage of the guts which may cause injury of the gut lining, morbidity and mortality. Small sizes of the microplastics enhance their translocation across the gastro-intestinal membranes via endocytosis-like mechanisms and distribution into tissues and organs. While in biological systems, microplastics increase dysregulation of gene expression required for the control of oxidative stress and activating the expression of nuclear factor E2-related factor (Nrf) signaling pathway in marine vertebrates and invertebrates. These alterations are responsible for microplastics induction of oxidative stress, immunological responses, genomic instability, disruption of endocrine system, neurotoxicity, reproductive abnormities, embryotoxicity and trans-generational toxicity. It is possible that the toxicological effects of microplastics will continue beyond 2020 the timeline for its ending by world environmental groups. Considering that most countries in African and Asia (major contributors of global plastic pollutions) are yet to come to terms with the enormity of microplastic pollution. Hence, majority of countries from these regions are yet to reduce, re-use or re-circle plastic materials to enhance its abatement.