Sex may influence environmental diphenhydramine accumulation in Round Stingrays

Pharmaceutical Residues in Edible Oysters along the Coasts of the East and South China Seas and Associated Health Risks to Humans and Wildlife

The investigation of pharmaceuticals as emerging contaminants in marine biota has been insufficient. In this study, we examined the presence of 51 pharmaceuticals in edible oysters along the coasts of the East and South China Seas. Only nine pharmaceuticals were detected. The mean concentrations of all measured pharmaceuticals in oysters per site ranged from 0.804 to 15.1 ng g-1 of dry weight, with antihistamines being the most common. Brompheniramine and promethazine were identified in biota samples for the first time. Although no significant health risks to humans were identified through consumption of oysters, 100-1000 times higher health risks were observed for wildlife like water birds, seasnails, and starfishes. Specifically, sea snails that primarily feed on oysters were found to be at risk of exposure to ciprofloxacin, brompheniramine, and promethazine. These high risks could be attributed to the monotonous diet habits and relatively limited food sources of these organisms. Furthermore, taking chirality into consideration, chlorpheniramine in the oysters was enriched by the S-enantiomer, with a relative potency 1.1-1.3 times higher when chlorpheniramine was considered as a racemate. Overall, this study highlights the prevalence of antihistamines in seafood and underscores the importance of studying enantioselectivities of pharmaceuticals in health risk assessments.

Evaluation of subchronic toxicity of the compound of diphenhydramine hydrochloride and caffeine after 28 days of repeated oral administration in Sprague-Dawley rats and beagle dogs

This study was designed to evaluate the subchronic toxicity of the compound of diphenhydramine hydrochloride (DH) and caffeine in Sprague-Dawley (SD) rats and beagle dogs. A total of 180 SD rats (15/sex/group) were randomly divided into the compound low-, medium- and high-dose groups (51, 102, 204 mg/kg), DH group (60 mg/kg), caffeine group (144 mg/kg) and the vehicle control group. Sixty beagle dogs (5/sex/group) were randomly divided into the compound low-, medium- and high-dose groups (male: 14.20, 28.30, 56.60 mg/kg, female: 5.66, 14.20, 28.30 mg/kg), DH group (male: 16.60 mg/kg, female: 8.30 mg/kg), caffeine group (male: 40.00 mg/kg, female: 20.00 mg/kg) and the vehicle control group. Rats and dogs were given continuous oral administration for 28 days following a 28-day recovery period. The adverse effects of the compound on rats and beagle dogs mainly included anorexia and liver function impairment. Most adverse effects induced by administration were reversible. Under the experimental conditions, the no-observed-adverse-effect level (NOAEL) of the compound of DH and caffeine was 51 mg/kg/day for SD rats and 28.30 mg/kg/day (male) and 5.66 mg/kg/day (female) for beagle dogs.

Sublethal, sex-specific, osmotic, and metabolic impairments in embryonic and adult round stingrays from a location exposed to environmental contamination in southern California, USA

Organic contaminants are known to affect a suite of physiological processes across vertebrate clades. However, despite their ancient lineage and important roles in maintaining healthy ecosystems, elasmobranchs (sharks, skates, and rays) are understudied with regard to sublethal effects of contaminant exposure on metabolic processes. Perturbations resulting from contaminant exposure can divert energy away from maintaining physiological homeostasis, particularly during energetically challenging life stages, such as pregnancy and embryonic development. Using the round stingray (Urobatis halleri) as a model elasmobranch species, we captured adult males and pregnant females (matrotrophic histotrophy) and their embryos from two populations differing in their environmental exposure to organic contaminants (primarily polychlorinated biphenyls (PCBs)). Pregnant females from the PCB-exposed population experienced significant decreases from early- to late-pregnancy in tissue mass and quality not seen in reference females. PCB-exposed pregnant females also failed to maintain plasma urea concentrations as pregnancy progressed, which was accompanied by a loss in muscle protein content. Despite the energetic demands of late-term pregnancy, females had significantly greater liver lipid content than reproductively inactive adult males. PCB-exposed adult males also had high metabolic capacity (i.e., enzyme activity) for most substrate groupings of all sex-site groups, suggesting that males may be even more negatively impacted by contaminant exposure than pregnant females. Evidence that in utero exposure to PCBs via maternal offloading impairs embryo outcomes is accumulating. Embryos from the PCB-contaminated site had lower tissue quality measures and indications that sex-based differences were manifesting in utero as males had higher metabolic capacities than females. This study indicates that accumulated PCB contaminants are not physiologically inert in the stingray.

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

Elasmobranchs are particularly prone to accumulating contaminants due to their life history patterns and relatively high trophic position. However, several compounds, especially contaminants of emerging concern, have still not been well studied in this group. Here, we aimed to determine the occurrence and concentrations of several inorganic and organic contaminants in different tissues of the Brazilian guitarfish Pseudobatos horkelii. This species is a critically endangered species, endemic from the Southwest Atlantic which uses southern Brazilian waters as a nursery habitat. Polycyclic aromatic hydrocarbons (PAHs), emerging pesticides, pharmaceutical and personal care products (PPCPs) and trace metals were determined in five biological tissues in order to assess the accumulation and organotropism of these compounds. Except for chlorothalonil and triclosan, all compounds were detected in, at least, one tissue, mostly in liver samples. All compounds differed among tissues, with liver presenting the higher concentrations of several contaminants, followed by muscle and gills. PAHs and PPCPs were the most detected analytes and presented the highest concentrations among tissues. Diclofenac levels were determined, for the first time in elasmobranchs, and were relatively high, when compared to other fishes. Finally, relatively high concentrations of PAHs, dichlofluanid and octocrylene in muscle might be suggestive of chronic exposure, presenting also human health implications. Regarding trace metals, contrary to most elasmobranch studies, Hg levels were low in all tissues, whereas Cd and Pb here higher in liver, and gills and blood samples, respectively. Our results indicate that P. horkelii is exposed to several organic and inorganic which might affect this species in a long-term scale. Concerning the determination of emerging contaminants, it is likely that other elasmobranchs are also exposed to these compounds and special attention should be given to this issue in order to predict future effects on this group.

Legacy environmental polychlorinated biphenyl contamination attenuates the acute stress response in a cartilaginous fish, the Round Stingray

In a population of Round Stingrays (Urobatis halleri) sampled from mainland California (polychlorinated biphenyl [PCB] exposed site, n = 46), relative to a nearby offshore island (reference site, n = 34), we tested the hypothesis that stingrays from the PCB-exposed site would have a compromised stress response. Adult male and pregnant female (pregnancy = matrotrophic histotrophy), stingrays were captured via hook and line at both locations over a breeding season and plasma was sampled either immediately (Baseline, males = 10, females = 31), or after ∼5 min of struggle on the line followed by a 15 min confinement stressor (Stressed, males = 16, females = 23). Biomarkers of the primary stress response (1α-OH-corticosterone) and the secondary response (energy mobilization; glucose, glycogen, and lactate in liver and muscle) were assessed. Females from both sites demonstrated the expected primary stress response of 1α-OH-corticosterone elevation, but the contaminant-exposed males did not. PCB-exposed stingrays, regardless of sex, failed to produce a plasma glucose increase in response to the applied stress, even though the stressor increased liver glucose as expected. This suggests a dysfunction in glucose transport due to PCB exposure. The Round Stingray accumulates lower PCB loads than other, predatory elasmobranchs, and by extension, the stress axis effects could be more severely impacted in those species as well. Lay summary Legacy polychlorinated biphenyl (PCB) contamination continues to adversely affect marine life. We show that PCB-exposure interferes with the ability of pregnant female and adult male stingrays to mobilize the energy necessary to respond appropriately to an acute stress like capture. Other cartilaginous fish species, such as sharks, accumulate considerably more PCB as a result of their predatory diet, and are likely to be more adversely impacted.

Steroid concentrations in maternal serum and uterine histotroph in round stingrays (Urobatis halleri)

Despite a wide range of elasmobranch (sharks, skates and rays) matrotrophic strategies, and thus potentially diverse pathways for maternal-fetal hormone exchange, little attention has been given to uterine steroids during development. Round Stingrays (Urobatis halleri) with matrotrophic histotrophy were captured during every month of their annual reproductive season from post-ovulation to near parturition, and paired samples of plasma and histotroph were analyzed for a suite of steroid hormones using LC-ESI/MRM. Hormone concentrations within and between maternal and uterine compartments were compared using two markers of embryo development. Histotroph had consistently higher detection rates and concentrations of hormones than maternal plasma, especially during early pregnancy when embryos are yolk sac-dependent for nutrition. Peaks in histotroph testosterone concentrations preceded maternal plasma, suggesting that hormones were locally produced within the uterine compartment. Embryonic sexual differentiation based on the presence of visible claspers (male copulatory organs) coincided with peaks in histotroph progesterone, testosterone, 17-hydroxyprogesterone and estradiol, suggesting that, like mammalian pregnancy, elasmobranch embryonic steroids also contribute to their own developmental environment.

Legacy polychlorinated biphenyl contamination impairs male embryonic development in an elasmobranch with matrotrophic histotrophy, the round stingray (Urobatis halleri)

Anthropogenic chemical exposure can result in overall reductions in reproductive success. Using the round stingray (Urobatis halleri) as an elasmobranch model with internal gestation, we measured female fecundity and embryo growth from postovulation to near parturition to test the hypothesis that environmental polychlorinated biphenyl (PCB) contamination would impair reproductive success. Two sites were sampled from southern California, USA: the mainland site was exposed to legacy PCB contamination (with low exposure to other anthropogenic contaminants), and the offshore reference site at Catalina Island was a separate population with low anthropogenic influence. Contaminant-exposed embryos weighed less at each stage of development than reference embryos, while accumulating proportionately more liver mass over development. Furthermore, environmental contamination negatively affected male embryos more than female embryos. The present study is the first study to demonstrate a negative effect of contaminant exposure on elasmobranch embryo growth, with probable fitness costs later in life. Environ Toxicol Chem 2018;37:2904-2911. © 2018 SETAC.