Bioaccumulation of rare earth elements and trace elements in different tissues of the golden grey mullet (Chelon auratus) in the southern Caspian Sea

Rare earth elements are essential for modern life, although they are also classified as emerging pollutants. Currently, fish studies on these elements are very limited in general, but, with regard to the Caspian Sea, there is no reference to them at all. For this reason, our objective was to determine the concentrations of these elements in the golden grey mullet (Chelon auratus) and to contrast its bioaccumulation patterns with those of arsenic, cadmium, mercury and lead. For that purpose, 20 fish were caught in the southern part of the Caspian Sea. Heavy rare earth element concentrations were higher than light ones and the terbium levels were very high, probably due to anthropogenic contamination. The intestine tissue gave the highest concentrations, which could be indicative of a very low gastrointestinal absorption. For both rare earth and trace elements, muscle was the tissue that accumulated the least, despite which, cadmium and lead levels in muscle were of concer

Determination of the Heavy Metal Bioaccumulation Patterns in Muscles of Two Species of Mullets from the Southern Caspian Sea

Although fish is a food that supplies nutrients of a high biological value, they can also be a source of some harmful substances, such as heavy metals. In the same context, some human activities in the Caspian Sea have contaminated this ecosystem during the past few years. For those reasons, our objective consisted of determining the concentrations of heavy metals and evaluating their bioaccumulation patterns in the different types of musculature in two species of mullets of commercial interest, Chelon auratus and Chelon saliens, from the southern coast of this sea. For this purpose, 20 C. auratus and 29 C. saliens were caught off this coastline and the metal concentrations in 3 different muscle locations were analyzed: the ventral, dorsal and caudal muscles of each fish. The caudal muscle had higher concentrations of Cd, Cu, Pb, and Zn, whereas As, Hg and Ni accumulation seemed to be independent of the musculature type. Overall, the Cd, Hg, and Pb concentrations exceeded the maximum levels permitted in fish by the European Union. In addition, the relationships between pairs of metals were positive and elevated in all the cases, which could be a sign of heavy metal pollution in the region sampled. Therefore, it will be necessary to continue monitoring and evaluating the degree of pollution in the Caspian Sea

Health risk assessment of heavy metal concentration in muscle of Chelon auratus and Chelon saliens from the southern Caspian Sea

Heavy metals are one of the most serious pollutants in aquatic ecosystems, and their accumulation in fish products causes harmful effects on human health. In this context, we set out to determine the concentrations of heavy metals in the muscle of two fish species of commercial interest, Chelon auratus and Chelon saliens on the south coast of the Caspian Sea. We aimed to assess the degree of environment contamination in this area and to estimate the potential risk to human health derived from the consumption of fish. The mean concentrations of the different metals analysed were very varied in both species. In fact, some concentrations exceeded the permissible limits for the protection of human health for Cd and Pb, and some values of As were above those referenced by other authors in same species in the Caspian Sea. None of the estimated daily intake values exceeded the tolerable intake based on the consumption under consideration. Nonetheless, the accumulative hazard values evidenced a potential risk to human health, Pb and Hg being those giving a higher target hazard quotient. The cancer risk from exposure to As from fish consumption in children was above the “acceptable” risk to life. Thus, in view of the accumulative nature of heavy metals, a moderate and non-abusive fish consumption in this area, particularly in children, would be recommendable

Aliphatic hydrocarbons in fin spines of adult sturgeon (Acipenser stellatus) and their relationship with potentially toxic elements in the northern and southern regions of the Caspian Sea

Currently, the pollution of the Caspian Sea by the oil industry is one of the highest problems in this area. Critically endangered species inhabit this sea, such as sturgeons, whose ecological value is incalculable. Thus, we aimed to evaluate the level of contamination of aliphatic hydrocarbons of petroleum and its relation with several toxic elements directly on sturgeons spines. A total of 40 adult starry sturgeons (Acipenser stellatus) were obtained within a repopulation programme in the northern and southern coastal waters of the Caspian Sea. The marginal pectoral fin was extracted from each fish to determine aliphatic hydrocarbons, arsenic, cadmium, mercury, nickel, lead, and vanadium. Subsequently, the sturgeons were released. Clearly, the presence of hydrocarbons was evidenced in all the sampled areas finding higher concentrations in the northern areas (N1 = 1.35 ± 0.4; N2 = 1.65 ± 0.46; N3 = 1.27 ± 0.40; S1 = 0.61 ± 0.22; S2 = 0.85 ± 0.43 mg/kg). Furthermore, to a greater or lesser extent, some toxic elements, mainly Hg and As, have been linked to aliphatic hydrocarbons

Evaluation of the Effectiveness of Eugenol and MS-222 as Anesthetics in Zebrafish in Repeated Exposures and Post-Anesthesia Behaviour

The increasing use of the zebrafish (Danio rerio) in scientific experiments has made it necessary to implement anesthesia protocols guaranteeing minimum pain and suffering for these animals and ensuring the reliability of the results obtained from their research. Therefore, we aimed to compare the effectiveness of two anesthetics, eugenol and MS-222, in consecutive administrations and evaluate the zebrafish behaviour after repeated anesthesia. Thus, several zebrafish were anaesthetized with eugenol, MS-222, and buffered MS-222 three times repeatedly with a 24-h interval between each exposure. The induction and recovery periods were also timed. Their swimming frequency was determined after each exposure to assess their behaviour after the anesthesia. Anesthesia induction was quicker with eugenol compared to MS-222. However, eugenol presented longer recovery times, which were prolonged after each exposure. Also, the swimming frequency was reduced after each anesthesia with eugenol. The buffered version of MS-222 was more efficacious than the non-buffered one. Both versions of MS-222 did not affect the swimming frequency. Based on these findings, we recommend the utilization of MS-222 buffered rather than eugenol when repeated, brief-duration anesthesia is necessitated for a study

Immunohistochemical expression of aromatase cyp19a1a and cyp19a1b in the ovary and brain of zebrafish (Danio rerio) exposed to different concentrations of bisphenol A

Bisphenol A (BPA) is used to produce plastic and plastic derived products in multitude of daily utensils, being one of the industrial compounds most widely used. This endocrine disrupting chemical (EDCs) is a well-known environmental pollutant released into the aquatic environment from industrial wastewater, sewage sludge or landfill leachate. Aromatases are considered potential targets of EDCs with characteristics that make them suitable biomarkers of exposure to their effects. The main objective of our study was to evaluate the expression of cyp19a aromatase as a toxicological endpoint after BPA exposure through the identification and assessment of alterations of the main cells responsible for cyp19a1a and cyp19a1b expression in the zebrafish ovary and brain using different concentrations of BPA in water. Immunohistochemistry was used to analyze the expression of these enzymes in female zebrafish exposed and not exposed to different concentrations of BPA (1, 10, 100 and 1000 μg / L) in water (n = 6/group) for 14 days. The results obtained in this study showed that the cyp19a aromatase system, involved in the synthesis of steroid compounds, is specially located in distinct oocyte stages in the ovary (cyp19a1a) and in radial glial cells of the brain (cyp19a1b). An overexpression of these aromatases was observed after BPA exposure in zebrafish, peaking from a concentration of 10 µg/L and showing to be good biomarkers of exposure to identify the early effects of low BPA concentrations. To our knowledge, this study is the first to localize and quantify the expression of cyp19a1a and cyp19a1b in the cells of brain and ovary after fish exposure to different BPA concentrations in water

An overview of the health effects of bisphenol a from a one health perspective

Bisphenol A (BPA) is a chemical compound, considered as an “emerging pollutant”, that appears ubiquitously, contaminating the environment and food. It is an endocrine disruptor, found in a multitude of consumer products, as it is a constituent of polycarbonate used in the manufacture of plastics and epoxy resins. Many studies have evaluated the effects of BPA, using a wide range of doses and animal models. In this work, we carried out a review of relevant research related to the effects of BPA on health, through studies performed at different doses, in different animal models, and in human monitoring studies. Numerous effects of BPA on health have been described; in different animal species, it has been reported that it interferes with fertility in both females and males and causes alterations in their offspring, as well as being associated with an increase in hormone-dependent pathologies. Similarly, exposure to BPA has been related to other diseases of great relevance in public health such as obesity, hypertension, diabetes, or neurodevelopmental disorders. Its ubiquity and nonmonotonic behavior, triggering effects at exposure levels considered “safe”, make it especially relevant when both animal and human populations are constantly and inadvertently exposed to this compound. Its effects at low exposure levels make it essential to establish safe exposure levels, and research into the effects of BPA must continue and be focused from a “One Health” perspective to take into account all the factors that could intervene in the development of a disease in any exposed organism

Analysis of Indirect Biomarkers of Effect after Exposure to Low Doses of Bisphenol A in a Study of Successive Generations of Mice

Bisphenol A (BPA) is considered as being an emerging pollutant, to which both animal and human populations are continuously and inadvertently exposed. The identification of indirect biomarkers of effect could be a key factor in determining early adverse outcomes from exposure to low doses of BPA. Thus, this study on mice aims to evaluate and identify indirect biomarkers of effect through the analysis of their blood biochemistry, and of certain reproduction parameters after exposure to different BPA concentrations (0.5, 2, 4, 50, and 100 µg/kg BW/day) in drinking water over generations. Our results showed that there were no modifications in the reproductive parameters evaluated, like estrous cycle duration, litter size, or the percentage of the young alive at reaching the weaning stage, at the exposure levels evaluated. However, there were modifications in the biochemical parameters, e.g., alterations in the glucose levels, that increased significantly (p < 0.05) in the breeders at the higher exposure doses (50 and 100 µg/kg BW/day in F1; 50 µg/kg BW/day in F2 and 100 µg/kg BW/day in F3), that would suggest that the BPA could induce hyperglycemia and its complications in adult animals, probably due to some damage in the pancreas cells; albumin, that increased in the breeders exposed to the highest dose in F1 and F3, inferring possible hepatic alterations. Further, total proteins showed a diminution in their values in F1 and F2, except the group exposed to 100 µg/kg BW/day, whereas in F3 the values of this parameter increased with respect to the control group, this aspect likely being related to a possible hepatic and renal alteration. Based on these results, glucose, albumin, and total proteins could initially be considered as early indicators of indirect effect after prolonged exposure to low BPA doses over generations

Analysis of Blood Biochemistry and Pituitary-Gonadal Histology after Chronic Exposure to Bisphenol-A of Mice

Bisphenol-A is an emerging pollutant that is widespread in the environment, and to which live beings are continuously and inadvertently exposed. It is a substance with an endocrine-disrupting capacity, causing alterations in the reproductive, immunological, and neurological systems, among others, as well as metabolic alterations. Our study aimed to assess its clinical signs, and effects on the most relevant blood biochemical parameters, and to evaluate pituitary and gonadal histology after a chronic exposure of adult mice to different BPA doses (0.5, 2, 4, 50 and 100 µg/kg BW/day) through their drinking water. The biochemical results showed that a marked significant reduction (p < 0.05) was produced in the levels of serum glucose, hypoproteinaemia and hypoalbuminemia in the groups exposed to the highest doses, whereas in the group exposed to 50 µg/kg BW/day the glucose and total protein levels dropped, and the animals exposed to 100 µg/kg BW/day experienced a diminution in albumin levels. In the case of the group exposed to 50 µg/kg BW/day, however, hypertriglyceridemia and hypercholesterolemia were determined, and the blood parameters indicating kidney alterations such as urea and creatinine experienced a significant increase (p < 0.05) with respect to the controls. Regarding the pituitary and gonads, none of the animals exposed presented histological alterations at the doses tested, giving similar images to those of the control group. These results suggest that continuous exposure to low BPA doses could trigger an inhibition of hepatic gluconeogenesis, which would result in a hypoglycaemic state, together with an induction of the enzymes responsible for lipidic synthesis, a mechanism by which the increase in the lipid and serum cholesterol levels could be explained. Likewise, the decline in the protein and albumin levels would be indicative of a possible hepatic alteration, and the increase in urea and creatinine would point to a possible renal perturbation, derived from continuous exposure to this xenobiotic. Based on our results, it could be said that chronic exposure to low BPA doses would not produce any clinical signs or histological pituitary-gonadal effects, but it could cause modifications in some blood biochemical parameters, that could initially indicate a possible hepatic and renal effect

Evaluation of the Toxicity of Bisphenol A in Reproduction and Its Effect on Fertility and Embryonic Development in the Zebrafish (Danio rerio)

Bisphenol A (BPA) is a chemical substance commonly used in the manufacture of plastic products. Its inhalation or ingestion from particles in suspension, water, and/or polluted foods can trigger toxic effects related to endocrine disruption, resulting in hormonal, reproduction, and immunological alterations in humans and animals. The zebrafish (Danio rerio) is an ideal experimental model frequently used in toxicity studies. In order to assess the toxic effects of BPA on reproduction and embryonic development in one generation after parental exposure to it, a total of 80 zebrafish, males and females, divided into four groups in duplicate (n = 20) were exposed to BPA concentrations of 500, 50, and 5 µg L−1, along with a control group. The fish were kept in reproduction aquariums for 21 days. The embryos obtained in the crosses were incubated in a BPA-free medium and observed for signs of embryotoxicity. A histopathological study (under optical and electron microscopes) was performed of adult fish gonads. The embryos of reproducers exposed to BPA were those most frequently presenting signs of embryotoxicity, such as mortality and cardiac and musculoskeletal malformations. In the histopathological studies of adult individuals, alterations were found in ovocyte maturation and in spermatazoid formation in the groups exposed to the chemical. Those alterations were directly related to BPA action, affecting fertility in both sexes, as well as the viability of their offspring, proportionally to the BPA levels to which they were exposed, so that our results provide more information by associating toxic effects on the offspring and on the next generation