Investigating the Sub-Lethal Effects of Mercury Exposure Using Environmental Sentinels

Mercury (Hg) is a ubiquitous environmental contaminant that is bioaccumulative and toxic. Ecosystems accumulate high mercury concentrations throughout their food web based on their unique environmental characteristics, exposing predators in these environments to mercury concentrations that elicit toxic effects, which are rarely observed outside of the laboratory. These predators provide the opportunity to investigate the sub-lethal effects of chronic mercury exposure that occur prior to the onset of toxic effects. Here the American alligator is thoroughly assessed for use as a sentinel of human dietary mercury exposure. We find that wild healthy alligators from the southeastern Atlantic coast of the US are exposed to mercury concentrations comparable to human populations with several different diets, and can be used as a sentinel for lifetime mercury exposure. The range of mercury concentrations that alligators are exposed to provide the opportunity to examine biochemical changes as sub-lethal effects, along an increasing mercury gradient. We observe that DNA methylation and mercury concentration are inversely correlated, but may be reversible based on diet. This epigenetic modification provides as assessment tool that can also be used for prevention in humans. To investigate underlying biochemical changes associated with increasing mercury exposure, a laboratory model of chronic exposure was assessed using an NMR based metabolomics approach. The diamondback terrapin, which is an established sentinel for mercury exposure, experienced both sub-lethal, and toxic effects, providing the opportunity to examine the onset of toxicity. We observed changes in small molecules involved in oxidative stress management throughout the range of mercury exposures, prior to toxic effects being observed. The terrapins experiencing toxic effects had behavioral changes commonly associated with mercury poisoning, such as neurological and muscular impairment. Many small molecules were altered in these terrapins, but most were related to their impaired foraging abilities. The Adverse Outcome Pathway (AOP) framework is used to put these data into a greater context that can be used for risk assessment for humans and wildlife. The AOP framework can be used for the prevention of toxicity, and a more complete understanding of the sub-lethal changes associated with this toxic contaminant

A Systematic Review and Meta-Analysis Investigating the Relationship between Exposures to Chemical and Non-Chemical Stressors during Prenatal Development and Childhood Externalizing Behaviors

Childhood behavioral outcomes have been linked to low quality intrauterine environments caused by prenatal exposures to both chemical and non-chemical stressors. The effect(s) from the many stressors a child can be prenatally exposed to may be influenced by complex interactive relationships that are just beginning to be understood. Chemical stressors influence behavioral outcomes by affecting the monoamine oxidase A (MAOA) enzyme, which is involved in serotonin metabolism and the neuroendocrine response to stress. Non-chemical stressors, particularly those associated with violence, have been shown to influence and exacerbate the externalizing behavioral outcomes associated with low MAOA activity and slowed serotonin metabolism. The adverse developmental effects associated with high stress and maternal drug use during pregnancy are well documented. However, research examining the combined effects of other non-chemical and chemical stressors on development and childhood outcomes as a result of gestational exposures is scarce but is an expanding field. In this systematic review, we examined the extant literature to explore the interrelationships between exposures to chemical and non-chemical stressors (specifically stressful/traumatic experiences), MAOA characteristics, and childhood externalizing behaviors. We observed that exposures to chemical stressors (recreational drugs and environmental chemicals) are significantly related to externalizing behavioral outcomes in children. We also observed that existing literature examining the interactions between MAOA characteristics, exposures to chemical stressors, and traumatic experiences and their effects on behavioral outcomes is sparse. We propose that maternal stress and cortisol fluctuations during pregnancy may be an avenue to link these concepts. We recommend that future studies investigating childhood behaviors include chemical and non-chemical stressors as well as children’s inherent genetic characteristics to gain a holistic understanding of the relationship between prenatal exposures and childhood behavioral outcomes

Investigating the Potential Role of Persistent Organic Pollutants in Hawaiian Green Sea Turtle Fibropapillomatosis

It has been hypothesized for decades that environmental pollutants may contribute to green sea turtle fibropapillomatosis (FP), possibly through immunosuppression leading to greater susceptibility to the herpesvirus, the putative causative agent of this tumor-forming disease. To address this question, we measured concentrations of 164 persistent organic pollutants (POPs) and halogenated phenols in 53 Hawaiian green turtle (<i>Chelonia mydas</i>) plasma samples archived by the Biological and Environmental Monitoring and Archival of Sea Turtle Tissues (BEMAST) project at the National Institute of Standards and Technology Marine Environmental Specimen Bank. Four groups of turtles were examined: free-ranging turtles from Kiholo Bay (0% FP, Hawaii), Kailua Bay (low FP, 8%, Oahu), and Kapoho Bay (moderate FP, 38%, Hawaii) and severely tumored stranded turtles that required euthanasia (high FP, 100%, Main Hawaiian Islands). Four classes of POPs and seven halogenated phenols were detected in at least one of the turtles, and concentrations were low (often <200 pg/g wet mass). The presence of halogenated phenols in sea turtles is a novel discovery; their concentrations were higher than most man-made POPs, suggesting that the source of most of these compounds was likely natural (produced by the algal turtle diet) rather than metabolites of man-made POPs. None of the compounds measured increased in concentration with increasing prevalence of FP across the four groups of turtles, suggesting that these 164 compounds are not likely primary triggers for the onset of FP. However, the stranded, severely tumored, emaciated turtle group (<i>n</i> = 14) had the highest concentrations of POPs, which might suggest that mobilization of contaminants with lipids into the blood during late-stage weight loss could contribute to the progression of the disease. Taken together, these data suggest that POPs are not a major cofactor in causing the onset of FP

Tracking aquatic animals to understand a world increasingly shaped by a changing climate and extreme weather events

Despite great promise for understanding the impacts and extent of climate change on aquatic animals, their species, and ecological communities, it is surprising that tracking tools, like biotelemetry and biologging devices, have not been extensively used to understand climate change or develop and evaluate potential interventions that may forestall or mitigate its effects. In this review, we provide an overview of methodologies and study designs that leverage available tracking tools to investigate aspects of climate change on aquatic ecosystems. Key interventions to protect aquatic life from the impacts of climate change, including habitat restoration, protected areas, conservation translocations, mitigations against interactive effects of climate change, and simulation of future scenarios can all be greatly facilitated by using electronic tagging and tracking. We anticipate that adapting study designs (e.g. use of replicated ponds, randomized control trials, physiologging) to effectively use tracking will greatly enhance our understanding of climate change and its impacts on aquatic ecosystems, hopefully also facilitating research into effective solutions and interventions against the most extreme and acute impacts

Application of the Consolidated Framework for Implementation Research to assess factors that may influence implementation of tobacco use treatment guidelines in the Viet Nam public health care delivery system

Background Services to treat tobacco dependence are not readily available to smokers in low-middle income countries (LMICs) where smoking prevalence remains high. We are conducting a cluster randomized controlled trial comparing the effectiveness of two strategies for implementing tobacco use treatment guidelines in 26 community health centers (CHCs) in Viet Nam. Guided by the Consolidated Framework for Implementation Research (CFIR), prior to implementing the trial, we conducted formative research to (1) identify factors that may influence guideline implementation and (2) inform further modifications to the intervention that may be necessary to translate a model of care delivery from a high-income country (HIC) to the local context of a LMIC. Methods We conducted semi-structured qualitative interviews with CHC medical directors, health care providers, and village health workers (VHWs) in eight CHCs (n = 40). Interviews were transcribed verbatim and translated into English. Two qualitative researchers used both deductive (CFIR theory driven) and inductive (open coding) approaches to analysis developed codes and themes relevant to the aims of this study. Results The interviews explored four out of five CFIR domains (i.e., intervention characteristics, outer setting, inner setting, and individual characteristics) that were relevant to the analysis. Potential facilitators of the intervention included the relative advantage of the intervention compared with current practice (intervention characteristics), awareness of the burden of tobacco use in the population (outer setting), tension for change due to a lack of training and need for skill building and leadership engagement (inner setting), and a strong sense of collective efficacy to provide tobacco cessation services (individual characteristics). Potential barriers included the perception that the intervention was more complex (intervention characteristic) and not necessarily compatible (inner setting) with current workflows and staffing historically designed to address infectious disease prevention and control rather than chronic disease prevention and competing priorities that are determined by the MOH (outer setting). Conclusions In this study, CFIR provided a valuable framework for evaluating factors that may influence implementation of a systems-level intervention for tobacco control in a LMIC and understand what adaptations may be needed to translate a model of care delivery from a HIC to a LMIC. Trial registration NCT02564653 . Registered September 201

Determinants of pregnant women's compliance with alcohol guidelines: a prospective cohort study

<p>Abstract</p> <p>Background</p> <p>In 2009, Australian alcohol guidelines for pregnancy changed from low to no alcohol intake. Previous research found a high proportion of pregnant Australian women drank during pregnancy; however, there has been limited investigation of whether pregnant women comply with 2009 alcohol guidelines. The purpose of this study was to provide an assessment of pregnant women’s compliance with 2009 Australian alcohol guidelines and identify predictors of such compliance, including previous drinking behaviour.</p> <p>Methods</p> <p>Cross-sectional analysis of prospective data from the 1973–1978 cohort of the Australian Longitudinal Study on Women’s Health was conducted. Women aged 30–36 years who were pregnant at the 2009 survey and had data on alcohol use were included (n = 837). Compliance with 2009 alcohol guidelines for pregnancy was defined as no alcohol intake. Predictors of compliance were analysed using multivariate logistic regression, controlling for area of residence, in three separate models to account for multicollinearity between measures of previous alcohol intake (compliance with 2001 guidelines; frequency and quantity; bingeing). Private health insurance, household income, and illicit drug use were entered into all models and retained if significant.</p> <p>Results</p> <p>72% of pregnant women did not comply with the 2009 alcohol guidelines and 82% of these women drank less than seven drinks per week, with no more than one or two drinks per drinking day. The odds of complying with abstinence increased by a factor of 3.48 (95% CI 2.39-5.05) for women who previously complied with the 2001 alcohol guidelines and decreased by a factor of 0.19 (95% CI 0.08-0.66) if household incomes were $36,400 or more. In other models the odds of complying were lower for women who consumed alcohol before pregnancy at least weekly (OR = 0.40, 95% CI 0.25-0.63) or binged (OR ≥ 0.18, 95% CI 0.10-0.31) and were higher for those who abstained (OR = 45.09; 95% CI 8.63-235.49) prior to pregnancy.</p> <p>Conclusion</p> <p>Most pregnant women did not comply with alcohol guidelines promoting abstinence. Prior alcohol behaviour was the strongest predictor of compliance during pregnancy, suggesting alcohol use should be addressed in women of child-bearing age. The study is limited by the relatively short timeframe between the official introduction of the 2009 guidelines and the date the surveys were sent out. Widespread dissemination of the guidelines may be necessary to help increase guideline compliance by pregnant women.</p