ABSTRACT
We searched for an extraction method that would allow a precise quantification of metal(loid)s in milligram-size samples using high-resolution graphite furnace atomic absorption spectrometry (HR-GFAAS). We digested biological (DORM-4, DOLT-5 and TORT-3) and sediment (MESS-4) certified reference materials (CRMs) using nitric acid in a drying oven, aqua regia in a drying oven, or nitric acid in a microwave. In addition, we digested MESS-4 using a mixture of nitric and hydrofluoric acids in a drying oven. We also evaluated the effect of sample size (100 and 200 mg) on the extraction efficiency. Nitric acid extraction in a drying oven yielded the greatest recovery rates for all metal(loid)s in all tested CRMs (80.0 %-100.0 %) compared with the other extraction methods tested (67.3 %-99.2 %). In most cases, the sample size did not have a significant effect on the extraction efficiency. Therefore, we conclude that nitric acid digestion in a drying oven is a reliable extraction method for milligram-size samples to quantify metal(loid)s with HR-GFAAS. This validated method could provide substantial benefits to environmental quality monitoring programs by significantly reducing the time and costs required for sample collection, storage, transport and preparation, as well as the amount of hazardous chemicals used during sample extraction and analysis. â¢Sample digestion with nitric acid in a drying oven yielded the greatest recovery rates of metal(loid)s from biological and sediment certified reference materials.â¢The recovery rates of metal(loid)s from biological and sediment certified reference materials using nitric acid digestion in a drying oven ranged from 73 % to 100 %.â¢Digestion with nitric acid in a drying oven is a simple and reliable method to extract small size environmental samples for metal(loid)s quantification by high-resolution graphite furnace atomic absorption spectrometry.
ABSTRACT
Concentrations of one metalloid (As) and eight metals (Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) were determined in tissues (muscle, liver, and kidney) of eight snake species (Bothrops neuwiedi, Crotalus durissus, Dipsas mikanii, Epicrates crassus, Helicops modestus, Micrurus carvalhoi, Oxyrhopus guibei, and Oxyrhopus trigeminus) from Lagoa Santa Karst. Except for Cu and Zn, all other analyzed elements were detected in concentrations within the ranges previously reported for snakes inhabiting polluted areas, emphasizing Hg (specific Hg mean concentrations varied from 0.87 to 9.76 µg g-1 d.w). The highest mean concentrations of all elements except Zn were found in muscle samples of the false corals O. guibei (means ranged from 2.01 [Pb] to 9.76 [Hg]). The highest Zn mean concentration (13.77 µg g-1 d.w) was detected in the kidney of the water snake H. modestus. No significant correlation was found between element concentrations and body size for all species. Significant interorgan differences were observed for As, Cr, Cu, Hg, Mn, Pb, and Zn concentrations in the three tissues in H. modestus. Significant interspecific differences were found in at least one organ for all elements. Significant pairwise differences were found between diet specialist species and between these species and broader diet species, while no significant difference was found between the broader diet species. The bioaccumulation of As and metals in snakes from Lagoa Santa Karst could be associated with natural rock dissolution and erosion processes but also with the wide-scale mining in the region and the increased agriculture and urbanization.
Subject(s)
Arsenic , Environmental Monitoring , Snakes , Animals , Arsenic/analysis , Arsenic/metabolism , Brazil , Metals/analysis , Kidney/chemistry , Water Pollutants, Chemical/analysis , Liver/chemistryABSTRACT
This study examines the effects of Roundup Transorb® (RDT) exposure on reproductive functions and ovarian miRNA expression in Austrolebias charrua. Exposure to RDT (at 0.065 or 5â¯mg. L-1 for 96â¯h) significantly disrupts fertility, evidenced by changes in fertilization rates and egg diameter. Profiling of ovarian miRNAs identified a total 205 miRNAs in A. charrua. Among these, three miRNAs were upregulated (miR-10b-5p, miR-132-3p, miR-100-5p), while ten miRNAs were downregulated (miR-499-5p, miR-375, miR-205-5p, miR-206-3p, miR-203a-3p, miR-133b-3p, miR-203b-5p, miR-184, miR-133a-3p, miR-2188-5p) compared to non-exposed fish. This study reveals that differentially expressed miRNAs are linked to molecular pathways such as steroid hormone biosynthesis, lipid and carbohydrate metabolism, bioenergetics, and antioxidant defense. It also analyzes molecular interactions between miRNAs and target genes during RDT exposure in annual killifish, providing insights into biomarkers in ecotoxicology. Moreover, it provides scope for developing environmental health assessment models based on epigenomic endpoints, supporting the protection of biodiversity and ecosystem services through the quantification of stress responses in living organisms exposed to pesticides.
ABSTRACT
There is a consensus that electroneutral Na+/H+ exchangers (NHEs) are important in branchial Na+ uptake in freshwater fish. There is also widespread belief, based on mammalian data, that EIPA [5-(N-ethyl-N-isopropyl)-amiloride]], and HMA [5-(N,N-hexamethylene)-amiloride)] are more potent and specific in blocking Na+ uptake than amiloride. We evaluated this idea by testing the three drugs at 10-7 to 10-4 M, i.e. 0.1 to 100 µM in two model species, rainbow trout (Oncorhynchus mykiss) and goldfish (Carassius auratus), using 22Na+ to measure unidirectional Na+ influx and efflux rates. In both species, the potency order for inhibiting unidirectional Na+ influx was HMA > amiloride > EIPA (IC50 values in the 10-70 µM range), very different from in mammals. At 100 µM, all three drugs inhibited Na+ influx by >90% in both species, except for amiloride in goldfish (65%). However, at 60-100 µM, all three drugs also stimulated unidirectional Na+ efflux rates, indicating non-specific effects. In trout, HMA and EIPA caused significant increases (2.1- to 2.3-fold) in efflux rates, whereas in goldfish, significant efflux elevations were greater (3.1- to 7.2-fold) with all three drugs. We conclude that the inhibitory potency profile established in mammals does not apply to the NHEs in fish gills, that non-specific effects on Na+ efflux rates are a serious concern, and that EIPA and HMA offer no clear benefits in terms of potency or specificity. Considering its much lower cost, we recommend amiloride as the drug of choice for in vivo experiments on freshwater fishes.
ABSTRACT
The use of effect biomarkers has contributed to the understanding of the sublethal effects of contaminants on different organisms. However, the analysis of genotoxic markers as an indicator of organism and environmental health in sharks is underexplored. Thus, the present study investigated the relationship between the genomic damage frequency in erythrocytes and metal(loid) concentrations in whole blood of three shark species (Galeocerdo cuvier, Negaprion brevirostris and Ginglymostoma cirratum), taking into account climatic seasonality. The results showed that G. cuvier, an apex predator, presented the highest total erythrocyte genomic damage frequencies together with the highest mean whole blood concentrations of Al, Cd, Cr, Fe, Mn, Ni, Pb and Zn. The shark N. brevirostris also presented high levels of metal(loid), indicating a greater susceptibility to these contaminants in species that preferentially feed on fish. In contrast, G. cirratum, a mesopredator, presented the lowest erythrocyte damage frequencies and whole blood metal(loid) concentrations. The presence of micronuclei was the most responsive biomarker, and Al, As and Zn had an important effect on the genomic damage frequencies for all species evaluated. Zn concentration influenced the binucleated cells frequencies and Al concentration had an effect on the total damage and micronuclei frequencies in G. cuvier and N. brevirostris. Binucleated cells and blebbed nuclei frequencies were affected by As concentration, especially in G. cirratum, while showing a strong and positive correlation with most of the metals analyzed. Nonetheless, baseline levels of metal(loid) blood concentrations and erythrocyte genomic damage frequencies in sharks have not yet been established. Therefore, minimum risk levels of blood contaminants concentrations on the health of these animals have also not been determined. However, the high genomic instability observed in sharks is of concern considering the current health status of these animals, as well as the quality of the environment studied.
Subject(s)
DNA Damage , Erythrocytes , Metals , Sharks , Water Pollutants, Chemical , Animals , Sharks/genetics , Sharks/blood , Water Pollutants, Chemical/toxicity , Water Pollutants, Chemical/blood , Erythrocytes/drug effects , Erythrocytes/metabolism , Metals/blood , Metals/toxicity , Environmental Monitoring/methods , Micronucleus Tests , Biomarkers/blood , Metals, Heavy/blood , Metals, Heavy/toxicityABSTRACT
Roundup Transorb® (RDT) is the most popular glyphosate-based herbicide (GHB) used in agriculture, and its impact extends to non-target organisms. The annual killifish Austrolebias charrua is an endangered species endemic to southern South America and inhabits temporary ponds. This study evaluates the effects of RDT concentrations (0.065 and 5 mg/L GAE) on A. charrua exposed for 96 h. Gene expression of cat, sod2, gstα, gclc, and ucp1 was evaluated on the liver and gills. Highlighting that even at low concentrations permitted by Brazilian legislation, the RDT can have adverse effects on A. charrua.
Subject(s)
Antioxidants , Glycine , Glyphosate , Herbicides , Water Pollutants, Chemical , Animals , Water Pollutants, Chemical/toxicity , Herbicides/toxicity , Glycine/analogs & derivatives , Glycine/toxicity , Pilot Projects , Fundulidae/genetics , Gene Expression/drug effects , Superoxide Dismutase/metabolism , Liver/metabolism , Liver/drug effects , Brazil , Gills/metabolism , KillifishesABSTRACT
Morphologically similar species that occupy resource-limited environments tend to differ in their ecological traits in order to coexist, which may result in differential exposure to environmental threats. For instance, partitioning of feeding resources may influence contaminant exposure and bioaccumulation in marine predators through different diets or foraging habitats. Here, we sampled three tropical seabird species breeding in sympatry in the southwestern Atlantic Ocean for blood and feather trace element concentrations (As, Hg, Cd, Pb), and assessed their foraging ecology with bio-logging (GPS tracks and time-depth recorders), analysis of regurgitated prey, and carbon and nitrogen stable isotope mixing models. Red-billed tropicbirds (Phaethon aethereus), brown (Sula leucogaster) and masked (S. dactylatra) boobies differed in their preferred foraging locations, the range of foraging trips, diving parameters and diets. In addition, interspecific differences were detected in blood or feathers for all trace elements analyzed, suggesting influence of the differences observed in diet and space use. Red-billed tropicbirds had the largest foraging range over the continental shelf and over the slope, suggesting lower exposure to continental sources of metals. Brown and masked boobies had higher Hg concentrations than tropicbirds, higher δ15N values (a proxy for trophic level), and δ15N correlated with Hg levels, suggesting biomagnification of Hg along the food chain. Nonetheless, red-billed tropicbirds showed comparable levels of As and Cd in blood or feathers, and higher levels of Pb in both tissues in comparison to boobies, which may suggest overall exposure of seabirds in the region, through their diets and foraging areas. Resource partitioning is critical for allowing coexistence of different seabird species in shared breeding sites where they act as central-place foragers. Nonetheless, in scenarios of environmental pollution, these species-specific strategies lead to differential bioaccumulation, and thus distinct effects of pollution on populations are expected.
Subject(s)
Birds , Environmental Monitoring , Trace Elements , Animals , Trace Elements/analysis , Trace Elements/metabolism , Birds/metabolism , Water Pollutants, Chemical/metabolism , Water Pollutants, Chemical/analysis , Feathers/chemistry , Atlantic Ocean , Cadmium/analysis , Cadmium/metabolism , SympatryABSTRACT
Marine pollution by trace elements is a global concern due to potential toxicity to species and ecosystems. Copper is a fundamental trace element for many organisms; however, it becomes toxic at certain concentrations. The green turtle (Chelonia mydas) is a good sentinel species, due to its circumglobal distribution, long life cycle, coastal habits when juvenile, and is subject to environmental pollution. Quantifying and comparing copper levels makes it possible to understand the availability of this trace element in nature. During this research, comparisons were made between the levels of copper found in the liver, kidneys, and muscles of 35 turtles, from the United States (Hawaii and Texas), Brazil, and Japan. Copper was found in all specimens. In the liver, animals from Hawaii (91.08 µg g-1), Texas (46.11 µg g-1), and Japan (65.18 µg g-1) had statistically equal means, while those from Brazil (16. 79 µg g-1) had the lowest means. For the kidney, copper means were statistically equal for all Hawaii (3.71 µg g-1), Texas (4.83 µg g-1), Japan (2.47 µg g-1), and Brazil (1.89 µg g-1). In muscle, the means between Texas (0.75 µg g-1) and Japan (0.75 µg g-1) were the same, and the mean for Brazil (0.13 µg g-1) was the lowest. Among the organs, the highest levels of copper were found in the liver (28.33 µg g-1) followed by the kidney (2.25 µg g-1) and with the lowest levels in the muscle (0.33 µg g-1). This is the first study of copper levels among marine vertebrates in distant parts of the globe using similar comparative filters between different locations. Similar levels in turtles from such distant locations may indicate that there is a pantropical pattern of copper distribution in the biota, and that these animals are subject to the process of bioavailability of this metal in the environment and metabolic regulation.
Subject(s)
Copper , Turtles , Water Pollutants, Chemical , Animals , Turtles/metabolism , Copper/analysis , Pacific Ocean , Water Pollutants, Chemical/analysis , Atlantic Ocean , Environmental Monitoring , Brazil , Liver/metabolism , Liver/chemistry , Kidney/chemistry , Japan , TexasABSTRACT
The annual killifish Austrolebias charrua is an endangered species, endemic to the southern region of South America, which inhabits temporary ponds that emerges in the rainy season. The main anthropogenic threat driving the extinction of A. charrua stems from extensive agriculture, primarily due to the widrespread use of glyphosate-based herbicides near their habitats. Annual killifishes have been used as models for ecotoxicological studies but, up to now, there are no studies about reference genes in any Austrolebias species. This represents an obstacle to the use of qPCR-based technologies, the standard method for gene expression quantification. The present study aimed to select and validate potential reference genes for qPCR normalization in the annual killifish Austrolebias charrua considering different tissues, gender and environmental conditions. The candidate reference genes 18 s, actb, gapdh, ef1a, shox, eif3g, and the control gene atp1a1 were evaluated in male and female individuals in three different tissues (brain, liver, and gills) under two experimental conditions (control and acute exposition to Roundup Transorb®). The collected tissues were submitted to RNA extraction, followed by cDNA synthesis, cloning, sequencing, and qPCR. Overall, 18 s was the most stable reference gene, and 18 s and ef1a were the most stable combination. Otherwise, considering all variables, gapdh and shox were the least stable candidate genes. Foremost, suitable reference genes were validated in A. charrua, facilitating accurate mRNA quantification in this species, which might be useful for developing molecular tools of ecotoxicological assessment based on gene expression analysis for environmental monitoring of annual killifish.
Subject(s)
Endangered Species , Real-Time Polymerase Chain Reaction , Animals , Male , Female , Water Pollutants, Chemical/toxicity , Fundulidae/genetics , Environmental Monitoring/methods , Glyphosate , Sex Factors , Herbicides/toxicity , KillifishesABSTRACT
We aimed to examine the responses of pollution biomarkers in feral fish from Astyanax genus collected at three hydrographic regions in southern Brazil and the capacity of these tools to differentiate between various levels of contamination. To achieve this, levels of organochlorine pesticides (liver), as well as the biomarkers AChE (muscle and brain), TBARS (liver), and EROD (liver) were assessed. Collections were conducted in four municipalities (Alegrete, Caraá, Lavras, and Santa Vitória) during 1 year, encompassing winter and summer. Fish from Alegrete were the most contaminated overall, but animals sampled in Caraá, and Lavras also displayed elevated levels of current-use pesticides. Elevated levels of endosulfans, DDTs, HCHs, and current-use pesticides were accompanied by elevated levels of TBARS in the liver. Conversely, fish from Santa Vitória exhibited the highest levels of PAHs, accompanied by elevated levels of EROD in the liver and reduced levels of AChE in muscle and brain. TBARS proved to be a reliable biomarker for assessing impacts arising from pesticide accumulation, while EROD and AChE served as valuable indicators of impacts resulting from PAHs accumulation. Ultimately, the results obtained in this study demonstrate the reliable use of the proposed biomarkers for tracking biological impacts stemming from aquatic pollution using feral Astyanax as biomonitoring species.
Subject(s)
Biomarkers , Environmental Monitoring , Pesticides , Water Pollutants, Chemical , Animals , Brazil , Biomarkers/metabolism , Water Pollutants, Chemical/analysis , Environmental Monitoring/methods , Pesticides/analysis , Characidae , Fishes , Polycyclic Aromatic Hydrocarbons/analysis , Hydrocarbons, Chlorinated/analysisABSTRACT
Chlorothalonil is a broad-spectrum organochlorine fungicide widely employed in agriculture to control fungal foliar diseases. This fungicide enters aquatic environments through the leaching process, leading to toxicity in non-target organisms. Organic contaminants can impact organism reproduction as they have the potential to interact with the neuroendocrine system. Although there are reports of toxic effects of chlorothalonil, information regarding its impact on reproduction is limited. The aim of the present study was to evaluate the influence of chlorothalonil on male reproductive physiology using the zebrafish (Danio rerio) as ecotoxicological model. Zebrafish were exposed for 7 days to two concentrations of chlorothalonil (0.1 and 10 µg/L) along with a control group (with DMSO - 0.001%). Gene expression of hypothalamus-pituitary-gonad axis components (gnrh2, gnrh3, lhr, fshr, star, hsd17b1, hsd17b3, and cyp19a1), as well as hepatic vitellogenin concentration were assessed. In sperm cells, reactive oxygen species (ROS) content, lipid peroxidation (LPO), mitochondrial functionality, and membrane integrity and fluidity were evaluated. Results indicate that exposure to the higher concentration of chlorothalonil led to a reduction in brain gnr2 expression. In gonads, mRNA levels of lhr, star, and hsd17b1 were decreased at both chlorothalonil concentrations tested. Similarly, hepatic vitellogenin concentration was reduced. Regarding sperm cells, a decreased ROS level was observed, without significant difference in LPO level. Additionally, a higher mitochondrial potential and lower membrane fluidity were observed in zebrafish exposed to chlorothalonil. These findings demonstrate that chlorothalonil acts as an endocrine disruptor, influencing reproductive control mechanisms, as evidenced by changes in expression of genes HPG axis, as well as hepatic vitellogenin concentration. Furthermore, our findings reveal that exposure to this contaminant may compromise the reproductive success of the species, as it affected sperm quality parameters.
Subject(s)
Endocrine Disruptors , Fungicides, Industrial , Nitriles , Water Pollutants, Chemical , Animals , Male , Zebrafish/metabolism , Endocrine Disruptors/metabolism , Hypothalamic-Pituitary-Gonadal Axis , Reactive Oxygen Species/metabolism , Fungicides, Industrial/metabolism , Vitellogenins/metabolism , Semen , Gonads , Spermatozoa/metabolism , Reproduction , Water Pollutants, Chemical/metabolismABSTRACT
Monitoring of contaminant levels in wildlife over time is a tool for assessing the presence and persistence of environmental impacts at ecosystem, community and population levels. Tropical seabirds breeding in the Abrolhos Archipelago, 70 km off the Brazilian coast, forage in areas under the influence of the Doce River discharge. In 2015, the Fundão Dam collapsed and released ca 60 million tons of iron ore tailings into the ocean. In the present study, red-billed tropicbirds Phaethon aethereus and brown boobies Sula leucogaster breeding in Abrolhos were monitored over four years (2019-2022) for metal (Fe, Mn, Zn, Cu, Cr, Hg, Pb, Cd) and metalloid (As) concentrations in blood and feathers. Over six sampling events, metal (loid) concentrations showed strong temporal variation in both tissues. Overall, feathers showed greater element concentrations than blood, with stronger correlations between elements, especially Mn and the nonessential As, Cd, Hg and Pb. Mn is one of the major chemical markers of the Fundão Dam tailings. Metal (loid) concentrations in the tropical seabirds evaluated were above suggested threshold levels for most nonessential elements (As, Cd and Pb), especially in February 2021, when metal (loid) concentrations peaked in feathers. In this case, values were orders of magnitude higher than those observed in other sampling events. This occurred one year after a major rainy season in the Doce River basin, which increased river discharge of contaminated mud into the ocean, where contaminants are further remobilized by winds and currents, resulting in transference through the marine food web. This finding is consistent to what has been observed for other ecosystem compartments monitored in the region under the influence of the Doce River. Our findings highlight the utility of using tropical seabirds as sentinels of marine pollution, revealing strong temporal patterns in metal (loid) concentrations associated to bottom-up climatic processes.
Subject(s)
Arsenic , Disasters , Mercury , Water Pollutants, Chemical , Animals , Arsenic/analysis , Ecosystem , Feathers , Cadmium , Lead , Environmental Monitoring/methods , Birds , Brazil , Rivers , Water Pollutants, Chemical/analysisABSTRACT
This study aimed to analyze the toxic effects of Roundup Transorb® on the endangered Neotropical annual killifish Austrolebias charrua through the assessment of molecular and biochemical biomarkers. The fish were collected in temporary ponds and exposed to environmentally realistic concentrations of the herbicide (5 mg.L-1 for 96 h). The production of ROS, lipid peroxidation, DNA damage, and membrane fluidity were evaluated in the blood cells by flow cytometry. The mRNA expression of the antioxidant-related genes sod2, cat, gstα, atp1a1, gclc, and ucp1 across the brain, liver, and gills was quantified. The acute exposure of annual killifish to Roundup significantly increased ROS production, lipid peroxidation, and DNA damage in their erythrocytes. Likewise, Roundup Transorb® decreased membrane fluidity in the blood cells of the exposed fish. Gene expression analysis revealed that Roundup exposure alters the relative expression of genes associated with oxidative stress and antioxidant defense. Our results give rise to new insights into adaptive mechanisms of A. charrua in response to Roundup. Since Brazilian annual killifishes strongly risk extinction, this study paves the way for developing novel biotechnologies applied to environmental monitoring and aquatic toxicology assessment.
Subject(s)
Glyphosate , Herbicides , Animals , Antioxidants/metabolism , Glycine/toxicity , Reactive Oxygen Species/metabolism , Oxidative Stress , Herbicides/toxicity , Fishes/metabolism , Fundulus heteroclitus , Biomarkers/metabolismABSTRACT
In 2019, the largest oil spill ever recorded in tropical oceans in terms of extent occurred in Brazil. The oil from the spill was collected directly from the environment and used in an exposure experiment with the endangered reef-building coral Mussismilia harttii. The treatments of the experiment were control (without oil), 1% oil, 2.5% oil, and direct contact of coral with oil. The most abundant hydrocarbon in the seawater of the experiment was phenatrene, which is toxic to corals. However, overall, the concentration of PAHs was not very high. The analysis of the maximum photosynthetic capacity of Symbiodiniaceae dinoflagellates showed a small impact of oil on corals, mainly on the contact treatment. However, coral microbiomes were affected in all oil treatments, with the contact treatment showing the most pronounced impact. A greater number and abundance of stress-indicating and potentially pathogenic bacteria were found in all oil treatments. Finally, this highly weathered oil that had lain in the ocean for a long time was carrying potentially coral-pathogenic bacteria within the Vibrionaceae family and was able to transmit some of these bacteria to corals. Bacteria within Vibrionaceae are the main causes of disease in different species of corals and other marine organisms.
ABSTRACT
The present study aimed to determine persistent organic pollutants (POPs) and contaminants of emerging concern in endangered angelshark and guitarfish species from southeastern Brazil, and to investigate potential impacts of these compounds on morphometric indexes. Pesticides of emerging concern, pharmaceutical and personal care products (PPCPs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) were determined in hepatic and muscular tissues of Pseudobatos horkelii, P. percellens, Squatina guggenheim, and Zapteryx brevirostris obtained from artisanal and industrial fisheries operating in southeastern Brazil. Accumulation profiles and effects of contaminants on condition factor and hepatosomatic index were investigated. No differences were detected regarding species contaminant concentration, potentially due to similarities in habits, occurrence and trophic position shared by guitarfishes and angelsharks. Polycyclic aromatic hydrocarbons (23.2-495.3 ng g -1), and PPCPs such as diclofenac (Subject(s)
Pesticides
, Polychlorinated Biphenyls
, Polycyclic Aromatic Hydrocarbons
, Skates, Fish
, Water Pollutants, Chemical
, Animals
, Environmental Monitoring
, Persistent Organic Pollutants
, Brazil
, Bioaccumulation
, Halogenated Diphenyl Ethers
, Polycyclic Aromatic Hydrocarbons/analysis
, Pesticides/analysis
, Water Pollutants, Chemical/analysis
ABSTRACT
Copper ions (Cu) are one of the most frequent trace-contaminants found in Brazilian waters and, although considered as an essential element, in high concentrations can accumulate and induce toxicity. Biomarkers are important tools that can be used to assess these impacts, but to be considered trustworthy, they have to be previously tested in target organisms through laboratory studies under controlled conditions. However, many of these experiments are conducted using only males, as it is believed that the hormonal variation of females can bias the results, increasing data variability. Notwithstanding, few studies have actually tested this hypothesis, highlighting the importance of considering and measuring the role of sex in ecotoxicological studies. The aim this study was to evaluate the influence of sex on biomarkers classically used in environmental monitoring programs using the fish Poecilia vivipara as model. For this, females and males were exposed for 96 h to two Cu concentrations (9 and 20 µg/L) and a control group. In liver and gills, Cu accumulation, total antioxidant capacity (TAC) and lipid peroxidation (LPO) were evaluated. In addition, samples of peripheral blood were used for neutrophil to lymphocyte ratio determination, a measure of the onset of secondary stress. Results show that Cu hepatic accumulation did not differ between females and males, but higher levels of this metal were observed in exposed animals compared to control fish. Additionally, interactive effects were observed for hepatic LPO, as males showed elevated oxidative damage in comparison to females. Moreover, Cu exposure elevated hepatic LPO relative to control only in males, but this increase in oxidative damage was not accompanied by changes in liver TAC. On the other hand, differences in branchial Cu accumulation and LPO were not observed. Conversely, control females showed elevated TAC in comparison to control males, but Cu exposure eliminated this difference. Cu exposure also induced an increase in the N:L ratio, indicating the presence of a secondary stress response unrelated to sex. Ultimately, the findings of this study demonstrate that sex can influence the response of biomarkers that are typically used in ecotoxicological investigations in a multifaceted manner. As a result, using animals from a singular sex in such studies may result in consequential outcomes, potentially leading to underestimation or overestimation of results.
Subject(s)
Fundulidae , Poecilia , Water Pollutants, Chemical , Animals , Male , Female , Poecilia/physiology , Water Pollutants, Chemical/toxicity , Copper/toxicity , Copper/metabolism , Oxidative Stress , Antioxidants/metabolism , Biomarkers/metabolism , GillsABSTRACT
In this study, we examine markers of oxidative stress in the tetra Hyphessobrycon luetkenii collected from two locations in the copper contaminated João Dias creek (southern Brazil). Also, specimens were translocated from a clean reference section of the creek to a polluted stretch and vice-versa. Fish were held at in submerged cages for 96 h and then sacrificed. Nuclear abnormalities in erythrocytes and total antioxidant capacity, lipid peroxidation and protein carbonylation in gills, brain, liver and muscle displayed similar trends in both groups. Lipid peroxidation increased in all tissues of individuals translocated to the polluted site but only in liver and muscle of those translocated to the reference site. Increased protein carbonylation was also observed in gills of individuals translocated to the reference location. These results suggest similar oxidative stress among fish from the reference and polluted locations and that long-term metals exposure may require adaptations toward oxidative stress responses.
Subject(s)
Characidae , Water Pollutants, Chemical , Animals , Copper/toxicity , Copper/metabolism , Water Pollutants, Chemical/toxicity , Water Pollutants, Chemical/metabolism , Oxidative Stress , Characidae/metabolism , Fresh Water , Mining , Gills/metabolism , Lipid Peroxidation , Liver/metabolismABSTRACT
Coastal elasmobranchs are vulnerable to chemicals mostly due to their k-strategic life history characteristics and high trophic positions. Embryos might be particularly exposed through the maternal offloading of contaminants, possibly leading to disruptions during critical developmental phases. Yet, knowledge on biochemical outcomes of prenatal exposure in elasmobranchs is notably limited. Therefore, we aimed to investigate the effects of prenatal exposure to contaminants in embryos of the critically endangered Brazilian guitarfish, Pseudobatos horkelii. Polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), pharmaceuticals and personal care products, and metals were determined in embryos. Additionally, glutathione S-transferase activity (GST), glutathione (GSH), and metallothionein levels (MT) were analyzed. Finally, lipid peroxidation levels (LPO) and protein carbonyl groups (PCO) were assessed. Embryonic exposure depended on yolk consumption, which was conspicuous in earlier development. We observed a dilution effect of contaminants levels, potentially related to biotransformation of these compounds throughout the embryonic development. Nevertheless, GST was not correlated to contaminant concentrations. The multivariate relationship between antioxidant components (GSH and GST) and LPO and PCO was negative, suggesting the lack of efficient defense of these biomarkers in early development, leading to oxidative damage. In this context, our results indicate that prenatal exposure to contaminants might impact the redox status in embryos of P. horkelii, leading to oxidative damage. Furthermore, metal concentrations influenced MT levels, suggesting this as a potential detoxification pathway in this species.
Subject(s)
Elasmobranchii , Prenatal Exposure Delayed Effects , Skates, Fish , Water Pollutants, Chemical , Animals , Female , Humans , Antioxidants/metabolism , Oxidative Stress , Elasmobranchii/metabolism , Glutathione/metabolism , Metals/pharmacology , Skates, Fish/metabolism , Lipid Peroxidation , Embryonic Development , Water Pollutants, Chemical/analysis , Biomarkers/metabolismABSTRACT
Pollution is one of the biggest threats to marine life and trace elements are among the most toxic pollutants in this environment. Zn is an essential trace element for biota but becomes toxic at high concentrations. Sea turtles are good bioindicators of trace element pollution, due to their longevity and cosmopolitan distribution that allow bioaccumulation for years in their tissues. Determining and comparing Zn concentrations in sea turtles from faraway places is relevant for conservation due to the lack of knowledge of geographically broader distribution patterns of Zn in vertebrates. In this study, comparative analyses of bioaccumulation in the liver, kidney, and muscles of 35 C. mydas from Brazil, Hawaii, the USA (Texas), Japan, and Australia of statistically equal sizes were performed. Zn was found in all specimens, with the highest levels in the liver and kidneys. Specimens from Australia (30.58 µg g-1), Hawaii (31.91 µg g-1), Japan (29.99 µg g-1), and the USA (33.79 µg g-1) showed statistically equal means in the liver. Kidney levels were the same in Japan (35.09 µg g-1) and the USA (37.29 µg g-1) and the same in Australia (23.06 µg g-1) and Hawaii (23.31 µg/g). Specimens from Brazil had the lowest means in both organs (12.17 µg g-1 in the liver and 9.39 µg g-1 in the kidney). The pattern of equal Zn values for most specimens in the liver is an important finding, demonstrating that there are pantropical patterns in the distribution of this metal even in regions so far from each other. A possible explanation is due to the essential nature of this metal linked to metabolic regulation, in addition to the bioavailability for biological absorption in marine environments, such as RS in Brazil, with a lower standard bioavailability also found in other organisms. Therefore, factors such as metabolic regulation and bioavailability indicate that there is a pantropical distribution of Zn in marine biota and green turtles can be a useful model as a sentinel species.