Contaminant screening and tissue distribution in the critically endangered Brazilian guitarfish Pseudobatos horkelii

Ecotoxicology applied to conservation: Potential negative metal and metalloid contamination effects on the homeostatic balance of the critically endangered Brazilian guitarfish, Pseudobatos horkelii (Elasmobranchii: Rhinobatidae)

Metal contamination poses a significant threat to elasmobranchs, underscoring the need for targeted conservation approaches. The critically endangered Brazilian guitarfish, Pseudobatos horkelii, confronts an array of challenges, notably overexploitation, putting its survival at risk. Our study investigated the potential toxicity arising from arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) contamination across various adult guitarfish tissues from southeastern Brazil. Serological stress indicators, nutritional metabolites, and creatinine, an organ function marker, were also assessed, and Selenium (Se) levels were also investigated for possible protective effects. Our investigation unveiled significant correlations between metal concentrations and the determined physiological markers, shedding light on potential adverse effects. Remarkably, six correlations were indicative of how Hg and Pb negatively impact hepatic metabolite assimilation, while As was shown to influence renal phosphorus dynamics, Cd to affect rectal gland phosphorus regulation, and Pb to influence creatinine production in muscle tissue. Furthermore, Se demonstrated protective properties against Cd, Hg, and Pb, suggesting a role in alleviating the toxicity of these elements. Despite probable protective Se influences, the detected elemental interactions still suggest potential for organ impairment. These findings gain heightened significance within the context of the cumulative stressors faced by the Brazilian guitarfish, with metal contamination exhibiting the capacity to erode this species resilience against both anthropogenic and environmental pressures, thereby disrupting systemic equilibrium and jeopardizing wild populations. By investigating the intricate balance between metal accumulation and physiological consequences, our study contributes with crucial insights into potential conservation strategy formulations towards pollution for this critically endangered elasmobranch species.

A systematic review on polycyclic aromatic hydrocarbon contamination in elasmobranchs and associated human health risks

Polycyclic aromatic hydrocarbon (PAH) contamination is ubiquitous and comprises a significant worldwide concern in ecological and Public Health frameworks. Many aquatic biota representatives have been reported as contaminated by these toxic compounds, including one of the most threatened vertebrate groups, elasmobranchs (sharks and rays). Although elasmobranchs play important ecological roles and provide significant ecosystem services, they are highly consumed and comprise a cheap source of protein for humans globally. Studies concerning elasmobranch PAH contamination are, however, notably lacking. A systematic review was, thus, conducted herein to assess PAH elasmobranch contamination and discuss potential human health risks following the Preferred Reporting Item Statement Guidelines for Systematic Reviews and Meta-analyses (PRISMA) guidelines applying the Population (P), Intervention (I), Comparison I, and Outcome (O) (PICO) strategy. A total of 86 published papers were retrieved by this method and analyzed. Only nine studies of this total concerned PAH elasmobranch contamination, assessed in 10 shark species and one ray species, with only one study calculating human health risks. A significant knowledge gap is, thus, noted for this subject, indicating the need to monitor PAH elasmobranch contamination in consumed shark and ray species worldwide.

Evaluation of biometry and blood concentration of heavy metals in free-living Chelonia mydas with and without fibropapillomatosis in southern Brazil

The present study determined the presence of heavy metals in green sea turtles with and without fibropapillomatosis in Itapirubá and Cassino beaches, southern Brazil. The weight, curved length of the carapace and body index were determined and blood was collected to quantify the concentrations of cadmium, lead and mercury. A total of 51 blood samples were analyzed, being 46 positives for at least one of the metals. There was a greater number of juvenile turtles in Itapirubá, larger in size and weight than those in Cassino. No statistical differences were found between metal concentrations between regions or between turtles with and without fibropapillomatosis. There was no significant correlation between metal concentrations, biometric variables and the presence of fibropapilomatose. Metal concentrations were low in both regions, with the highest concentrations being Cd and the lowest Hg.

Impacts of water pollutants on chondrichthyans species from South America: A review

This is the first research that extensively compiles all the available scientific literature on the presence of trace metals (TMs), persistent organic pollutants (POPs), and plastic debris in Chondrichthyan species inhabiting South America (including the Atlantic and Pacific Oceans), providing an insight into Chondrichthyans as bioindicators of pollutants as well as the impacts of pollutant exposure on the organisms. Seventy-three studies were published in South America between 1986 and 2022. While 68.5% focused on TMs, 17.8% on POPs, and 9.6% on plastic debris. Brazil and Argentina were at the top in terms of the number of publications; however, there is an absence of information regarding pollutants for Chondrichthyans in Venezuela, Guyana, and French Guiana. Of the 65 Chondrichthyan species reported, 98.5% belong to the Elasmobranch group, and 1.5% from the Holocephalans. Most studies focused on Chondrichthyans of economic importance, and the most analyzed organs were the muscle and liver. There is a lack of studies on Chondrichthyan species with low economic value and critical conservation status. Due to their ecological relevance, distribution, accessibility, high trophic position, capacity to accumulate high levels of pollutants, and the number of studies published, Prionace glauca and Mustelus schmitii seem to be adequate to serve as bioindicators. For TMs, POPs, and plastic debris there is a lack of studies focusing on the pollutant levels as well as their effect on Chondrichthyans. Future research reporting TMs, POPs, and plastic debris occurrences in Chondrichthyan species are required in order to increase the scarce databases about pollutants in this group, with a clear need for further research on the responses of chondrichthyans to pollutants, as well as making inferences about the potential risks to the ecosystems and human health.

Consequences of prenatal exposure to contaminants in elasmobranchs: Biochemical outcomes during the embryonic development of Pseudobatos horkelii

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.

Distribution in marine fish and EDI estimation of contaminants of emerging concern by vortex-assisted matrix solid-phase dispersion and HPLC-MS/MS

Due to their persistence or continuous discharge, toxic substances are present in the aquatic environment, and can bioaccumulate and biomagnify in the food web, generating a significant ecological risk and a threat to human health. The present study assess the occurrence and tissue (muscle, liver, stomach and gills) distribution of 59 anthropogenic contaminants of emerging concern (CECs) in marine fish from Brazil. A simpler and faster analytical methodology based on vortex-assisted matrix solid-phase dispersion (VA-MSPD) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed and validated. Limits of quantification ranged from 3.31 to 114 ng g^-1 dw with recovery rates between 60 and 140 % and relative standard deviation below 20 %. The ultraviolet filters 4-hydroxybenzophenone (4HB) (benzophenone-3 metabolite) and benzocaine (Et-PABA), and the antibacterial salicylic acid were frequently accumulated in muscle and liver at concentrations between 39.5 and 21.0 ngg^-1 dw. The determined concentrations resulted to be lower than the tolerable daily intake recommended by the European Food Safety Authority (EFSA).

Agrochemical Residues in Fish and Bivalves from Sepetiba Bay and Parnaiba River Delta, Brazil

Accumulation of pesticides has a harmful impact on the environment and human health. The main goal of this work was to develop a method to determine and quantify the residues of thirteen pesticides in edible fish and bivalves such as parati (Mugil curema), seabass (Centropomus ssp.), mullet (Mugil brasiliensis), clams (Anomalocardia brasiliana) and mussel (Mytilus galloprovincialis) collected from Sepetiba Bay and Parnaiba River Delta (Brazil) between 2019 and 2020. Matrix solid-phase dispersion (MSPD) was used for extraction and quantification through gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). The method was validated (linearity, accuracy and precision) for fatty fish (Salmo salar), lean fish (Mugil curema) and bivalves (Mytilus edulis). The survey found linear correlation coefficients (r) equal to or greater than 0.9 for almost all analytes. The relative standard deviations (RSD) of five replicates were less than 20% for almost all analytes at different concentrations in lean fish, fatty fish and bivalves. Most analytes showed satisfactory accuracy. Alachlor herbicide was found in samples of seabass, mussels, clams and parati with levels ranging between 0.55 to 420.39 μg kg^-1 dw. Ethion was found in parati (maximum 211.22 μg kg^-1 dw), mussels (15.1 μg kg^-1 dw) and clams (maximum 44.50 μg kg^-1 dw). Alachlor was found in clams (maximum 93.1 μg kg^-1 dw), and bifenthrin was found in parati (maximum 43.4 μg kg^-1 dw) and clams (maximum 42.21 μg kg^-1 dw). The validated method was satisfactory for the determination of eleven pesticides in the fatty fish matrix, and thirteen pesticides in the samples of lean fish and bivalves. The presence of alachlor, ethion and bifenthrin stands out.

Updated knowledge, partitioning and ecological risk of pharmaceuticals and personal care products in global aquatic environments

Over the last few decades, the occurrence of pharmaceuticals and personal care products (PPCPs) in aquatic environments has generated increasing public concern. In this review, data on the presence of PPCPs in environmental compartments from the past few years (2014-2022) are summarized by carrying out a critical survey of the partitioning among water, sediment, and aquatic organisms. From the available articles on PPCP occurrence in the environment, in Web of Science and Scopus databases, 185 articles were evaluated. Diclofenac, carbamazepine, caffeine, ibuprofen, ciprofloxacin, and sulfamethoxazole were reported to occur in 85% of the studies in at least one of the mentioned matrices. Risk assessment showed a moderate to high environmental risk for these compounds worldwide. Moreover, bioconcentration factors showed that sulfamethoxazole and trimethoprim can bioaccumulate in aquatic organisms, while ciprofloxacin and triclosan present bioaccumulation potential. Regarding spatial distribution, the Asian and European continents presented most studies on the occurrence and effects of PPCPs on the environment, while Africa and Asia are the most contaminated continents. In addition, the impact of COVID-19 on environmental contamination by PPCPs is discussed.

Survey on endocrine-disrupting chemicals in seafood: Occurrence and distribution

Currently, the presence of endocrine disrupting chemicals (EDCs) in the marine environment pose а potential risk to both wildlife and human health. The occurrence of EDCs in seafood depends of several factors such as source and amounts of EDCs that reach the aquatic environment, physicochemical features of EDCs, and its accumulation in trophic chain. This review highlights the occurrence and distribution of EDCs along the seafood in the last 6 years. The following EDCs were included in this review: brominated flame retardants (PBDEs, PBBs, HBCDDs, TBBPA, and novel flame retardants); pharmaceuticals (paracetamol, ibuprofen, diclofenac, carbamazepine), bisphenols, hormones, personal care products (Musk and UV Filters), and pesticides (organochlorides, organophosphates, and pyrethroids). Some of them were found above the threshold that may cause negative effects on human, animal, and environmental health. More control in some countries, as well as new legislation and inspection over the purchase, sale, use, and production of these compounds, are urgently needed. This review provides data to support risk assessment and raises critical gaps to stimulate and improve future research.

Evaluation of polycyclic aromatic hydrocarbons in silky sharks Carcharhinus falciformis collected from Western Indian Ocean and human health risk assessment

The silky shark (Carcharhinus falciformis) is the most abundant and widely distributed shark species in the marine system of tropical regions. However, it appears that there is limited information on USEPA 16 polycyclic aromatic hydrocarbons (PAHs) concentration in silky shark muscle tissue, which has together with the lack of a health risk assessment of human consumption of silky shark filets. The potential toxicity of PAHs in muscles of silky sharks and cancer and non-cancer risk of consumers were assessed. Results showed that the total PAHs (TPAHs) concentration in the muscle tissue of silky sharks was between 62 and 657 ng/g ww, with an average of 234 ± 221 (mean ± standard deviation) ng/g ww, and can be considered as minimally to moderately contaminated level. Naphthalene (NA), phenanthrene (PH), and fluoranthene (FLU) are the most abundant PAHs in silky sharks muscle tissue, accounting for 38.6%, 11.0%, and 19.0% of TPAHs, respectively. The average values of toxic benzo[a]pyrene (BaP) equivalent (TEQ^carc) and toxic dioxin equivalent (TEQ^fish) of PAHs equal to the potency of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in silky shark muscle are 13.5 ± 16.4 ng BaP/g ww and 34.1 ± 77.4 pg TCDD/g ww, respectively, and they showed a good linear relationship (r = 0.928; p < 0.001). The TEQ^carc of silky sharks muscle is higher than USEPA's screening value of PAHs of 3.2 ng BaP/g ww for adults, indicating a potential negative impact on public health. The calculated hazard index (HI) of PAHs is less than 1, suggesting that residents eating silky shark muscle will not expect to cause significant non-cancer risk. However, the incremental lifetime cancer risk (ILCR) of BaP as 10.6-26.3% and 8.2-32.4% in males and females, respectively, may pose a significant cancer risk. In general, children and the elderly have relatively higher risks, as well as males have a higher cancer and non-cancer risk than females.

Drivers of biomagnification of Hg, As and Se in aquatic food webs: A review

Biomagnification of trace elements is increasingly evident in aquatic ecosystems. In this review we investigate the drivers of biomagnification of mercury (Hg), arsenic (As) and selenium (Se) in aquatic food webs. Despite Hg, As and Se biomagnify in food webs, the biomagnification potential of Hg is much higher than that of As and Se. The slope of trophic increase of Hg is consistent between temperate (0.20), tropical (0.22) and Arctic (0.22) ecosystems. Se exerts a mitigating role against Hg toxicity but desired maximum and minimum concentrations are unknown. Environmental (e.g. latitude, temperature and physicochemical characteristics) and ecological factors (e.g. trophic structure composition and food zone) can substantially influence the biomagnification process these metal (oids). Besides the level of bioaccumulated concentration, biomagnification depends on the biology, ecology and physiology of the organisms that play a key role in this process. However, it may be necessary to determine strictly biological, physiological and environmental factors that could modulate the concentrations of As and Se in particular. The information presented here should provide clues for research that include under-researched variables. Finally, we suggest that biomagnification be incorporated into environmental management policies, mainly in risk assessment, monitoring and environmental protection methods.

Assessing multigenerational exposure to metals in elasmobranchs: Maternal transfer of contaminants in a yolk-sac viviparous species

This study aimed to assess the maternal offloading of metals in the Brazilian guitarfishPseudobatos horkelii through determining essential (Cr, Cu, Fe) and non-essential (Cd, Hg, Pb) metal concentrations along two generations of this species: pregnant females and offspring. The maximum transfer capacity (ECER) and offspring/mother ratio were calculated to estimate the extent of offloading, as well as the proportion of contaminants presented in offspring related to the maternal concentrations. Transfer efficiency was element-dependent. Chromium had the highest ECER (99.7%), followed by Hg (67.7%). Other essential metals were less transferred (9.6-35.6%) and Cd and Pb were not detected in uterine content samples. The relationships between maternal length and concentration, as well as transfer capacity were not significant, indicating that females might be continuously exposed, and that offloading might not excrete metals efficiently. On the other hand, embryos are exposed to these elements which could impair embryonic development.

Persistent organic pollutants and chlorpyrifos in the cockfish Callorhinchus callorynchus (Holocephali: Callorhynchidae) from Argentine coastal waters: Influence of sex and maturity

Organic contaminants are of great environmental concern due to their negative impacts on coastal ecosystems, especially on highly vulnerable species as chondrichthyans. Accumulation of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and chlorpyrifos was assessed in muscle, gonads, and liver of the cockfish Callorhinchus callorynchus for both sexes and maturity stages. This species has a wide distribution in South Atlantic Ocean and it is an important resource for coastal Argentine fisheries. Pollutants were quantified by gas chromatography with electron capture detector and the distribution pattern found in C. callorynchus was the following: (∑OCPs+chlorpyrifos) > ∑PCBs>∑PBDEs. Endosulfan was predominant among OCP groups, penta-CBs and hexaCBs among PCBs and BDE 47, 66, 99, and 100 in PBDE group. The highest levels were found in liver followed by muscle and gonads. The highest percentage of lipids was also observed in the liver. Moreover, the concentrations of ∑OCPs and ∑PCBs in C. callorynchus liver varied with maturity stage, and ∑OCPs also with sexes. Females presented higher values than males, and mature individuals showed higher concentrations than immature ones, according with biological parameters such as age, sex, maturity stage, metabolic and redistribution processes and habitat use influence. These results indicate that C. callorynchus reflects a historical and recent contamination in their tissues, and therefore, especially females, becomes as a good biomonitor of these pollutants in the marine environment. To our knowledge, this work represents one of the few investigations on the occurrence of POPs and chlorpyrifos in chondrichtyans from South Atlantic Ocean; therefore more research is mandatory for an adequate management and conservation of existing fisheries and aquatic resources.

Metal contamination in threatened elasmobranchs from an impacted urban coast

Guitarfishes and angelsharks are two of the most endangered elasmobranch groups. Despite this, limited knowledge exists regarding the effects of environmental contamination in these groups. For this reason, this study assessed the concentrations of metals in liver and muscle of three guitarfishes (Pseudobatos horkelii, P. percellens, and Zapteryx brevirostris) and one angelshark species (Squatina guggenheim) captured during the year of 2019 in one of the most impacted areas in South America: the São Paulo State coast, Brazil, Southwest Atlantic. Cadmium (Cd) Chromium (Cr) Cupper (Cu) Iron (Fe), Mercury (Hg), and Lead (Pb) were determined by atomic spectrometry, with samples being previously acid digested. Among the non-essential metals, Cd had the highest mean concentrations for all species, followed by Pb and Hg, whereas Fe had the highest mean levels among the essential metals analyzed, followed by Cu and Cr. Liver and muscle samples had different concentrations, with liver presenting the highest concentrations. Except for Cd, non-essential metals had relatively low concentrations when compared to other elasmobranch species reported in the literature, which could be explained by the efficiency in metabolizing these compounds or differential life history patterns among the species studied herein and other. Considering that all species analyzed herein are typically consumed, human health impacts must be considered, especially concerning Cd concentrations. Furthermore, Cd, Cr and Pb were above the safety limits, indicating potential hazard for human consumption. In conclusion, our results suggest that these species are exposed to metals and that concentrations above the safety limits observed for these species must be taken into consideration regarding human consumption.

Maternal transfer of polycyclic aromatic hydrocarbons in an endangered elasmobranch, the Brazilian guitarfish

Maternal transfer of contaminants is an important route of exposure for many species during embryonic development, which might compromise the organism throughout its life cycle. Here, we report the maternal offloading of polycyclic aromatic hydrocarbons (PAHs) in an elasmobranch, the Brazilian guitarfish Pseudobatos horkelii. Eighteen PAHs were determined by gas chromatography in maternal liver and uterine content (uterine eggs and early-stage development embryos) samples to determine the maternal transfer rate. The mean rate of PAHs offloaded to the offspring was of 13%, with high variability among individual congener transfer (0.7-29.9%) and benzo[b]fluoranthene attaining the highest maternal transfer rates. Differential transfer rates were attributed to physicochemical proprieties of each compound, with low molecular level PAHs presenting the highest rates. A depuration mechanism in which females decrease their maternal transfer rate as a function of size, related to consecutive reproductive cycles was not properly observed in this study. From a conservation perspective, these results indicate that elasmobranchs embryos of an endangered species can be exposed to PAHs during their development and, considering the possible harmful effects of these compounds to other early life stage organisms, deleterious effects could be a possibility, although this was not analyzed herein.