Modulation in Persistent Organic Pollutant Concentration and Profile by Prey Availability and Reproductive Status in Southern Resident Killer Whale Scat Samples

Killer whale fecal samples: How to get the most out of a single extraction

Fecal samples are a non-invasive and relatively accessible matrix for investigating physiological processes in resident killer whale (Orcinus orca) populations. The high lipid content of the diet (primarily salmonids) leads to lower density fecal material and slower dispersion, facilitating sample collection. As fecal discharge is relatively infrequent and the volume of sample is variable, maximizing analytical options is an important consideration. Here we present an extraction methodology to measure hormones and lipid content from the same fecal aliquot. Lipid extractions are commonly conducted using chloroform and methanol from Folch or Bligh and Dyer (B&D), while alcohol is the primary solvent for hormone extraction. We evaluated the possibility of using the methanol layer from lipid extractions to assess fecal steroid hormone levels. Folch and B&D methanol residues were assayed form metabolites of progesterone (PMs) and corticosterone (GCs), and results were compared to aliquots extracted in 70 % ethanol. Hormone concentrations measured in the methanol layer from Folch and B&D extractions were 55 % to 79 % lower than concentrations in 70 % ethanol. We developed mathematical corrections, using linear regression models fitted to Folch or B&D methanol vs 70 % ethanol hormone concentrations (p < 0.01). Fecal concentrations of PMs and GCs from methanol extractions were biologically validated and are significantly higher in confirmed pregnant females compared to non-pregnant individuals (p < 0.05). This study demonstrates that lipid extraction protocols may be used for the analysis of multiple biomarkers, maximizing the use of small-volume samples.

Toxicological effects assessment for wildlife in the 21st century: Review of current methods and recommendations for a path forward

Model species (e.g., granivorous gamebirds, waterfowl, passerines, domesticated rodents) have been used for decades in guideline laboratory tests to generate survival, growth, and reproductive data for prospective ecological risk assessments (ERAs) for birds and mammals, while officially adopted risk assessment schemes for amphibians and reptiles do not exist. There are recognized shortcomings of current in vivo methods as well as uncertainty around the extent to which species with different life histories (e.g., terrestrial amphibians, reptiles, bats) than these commonly used models are protected by existing ERA frameworks. Approaches other than validating additional animal models for testing are being developed, but the incorporation of such new approach methodologies (NAMs) into risk assessment frameworks will require robust validations against in vivo responses. This takes time, and the ability to extrapolate findings from nonanimal studies to organism- and population-level effects in terrestrial wildlife remains weak. Failure to adequately anticipate and predict hazards could have economic and potentially even legal consequences for regulators and product registrants. In order to be able to use fewer animals or replace them altogether in the long term, vertebrate use and whole organism data will be needed to provide data for NAM validation in the short term. Therefore, it is worth investing resources for potential updates to existing standard test guidelines used in the laboratory as well as addressing the need for clear guidance on the conduct of field studies. Herein, we review the potential for improving standard in vivo test methods and for advancing the use of field studies in wildlife risk assessment, as these tools will be needed in the foreseeable future. Integr Environ Assess Manag 2024;20:699-724. © 2023 His Majesty the King in Right of Canada and The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Reproduced with the permission of the Minister of Environment and Climate Change Canada. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Simultaneous determination of steroid hormones and pharmaceuticals in killer whale (Orcinus orca) faecal samples by liquid chromatography tandem mass spectrometry

We describe a non-invasive method for profiling selected hormones, pharmaceuticals and personal care products (PPCPs) in killer whales (Orcinus orca) based on analysis of faecal samples by liquid chromatography tandem mass spectrometry (LC-MS/MS). The method targets 21 compounds of interest including glucocorticoids, mineralocorticoids, androgens, estrogens, progestogens, selective serotonin uptake inhibitors and an antibacterial/antifungal agent. This method is suitable for routine simultaneous determination of target compounds in killer whale faecal samples as well as validation of immunoassays for the detection and measurement of steroid hormones in faeces. The optimized method involves extraction of freeze-dried faecal material with reagent alcohol and water followed by isolation of the analytes using solid phase extraction with hydrophilic-lipophilic balance cartridges and liquid-liquid extraction with methyl tertiary-butyl ether. Reconstituted extracts were analysed by LC-MS/MS using an electrospray ionization interface. Method limit of quantification ranged from 0.06 to 45.2 ng/g in freeze-dried faecal samples. Except for sertraline, triclosan and estradiol (which was not recovered at the lowest spiked concentration), average intra- and inter-day precisions were within 10%, and average recoveries were between 89.3% and 129.3%, for faecal samples spiked with 5.3, 26.7 or 133 ng/g of each analyte. The method was applied successfully to the analysis of hormones and PPCPs in whale faeces during which 17α-hydroxyprogesterone, a common intermediate in steroid biosynthesis that cross-reacts with precursors and sulphated conjugates in immunoassays, was identified and quantified in all samples.

Emerging Contaminants and New POPs (PFAS and HBCDD) in Endangered Southern Resident and Bigg's (Transient) Killer Whales (Orcinus orca): In Utero Maternal Transfer and Pollution Management Implications

Killer whales (Orcinus orca) have been deemed one of the most contaminated cetacean species in the world. However, concentrations and potential health implications of selected 'contaminants of emerging concern' (CECs) and new persistent organic pollutants (POPs) in endangered Southern Resident and threatened Bigg's (Transient) killer whales in the Northeastern Pacific (NEP) have not yet been documented. Here, we quantify CECs [alkylphenols (APs), triclosan, methyl triclosan, and per- and polyfluoroalkyl substances (PFAS)] and new POPs [hexabromocyclododecane (HBCCD), PFOS, PFOA, and PFHxS] in skeletal muscle and liver samples of these sentinel species and investigate in utero transfer of these contaminants. Samples were collected from necropsied individuals from 2006 to 2018 and analyzed by LC-MS/MS or HRBC/HRMS. AP and PFAS contaminants were the most prevalent compounds; 4-nonylphenol (4NP) was the predominant AP (median 40.84 ng/g ww), and interestingly, 7:3-fluorotelomer carboxylic acid (7:3 FTCA) was the primary PFAS (median 66.35 ng/g ww). Maternal transfer ratios indicated 4NP as the most transferred contaminant from the dam to the fetus, with maternal transfer rates as high as 95.1%. Although too few killer whales have been screened for CECs and new POPs to infer the magnitude of contamination impact, these results raise concerns regarding pathological implications and potential impacts on fetal development and production of a viable neonate. This study outlines CEC and new POP concentrations in killer whales of the NEP and provides scientifically derived evidence to support and inform regulation to mitigate pollutant sources and contamination of Southern Resident killer whale critical habitat and other marine ecosystems.

Reproductive biology of female common dolphins (Delphinus delphis) in New Zealand waters

Reproductive biology was assessed in 106 female common dolphins (Delphinus delphis) examined post-mortem from stranding and bycatch events along the New Zealand coastline between 1997 and 2019. The average age (ASM) and length (LSM) at sexual maturity was estimated at 7.5 years and 183.5 cm, respectively. The total number of corpora in mature individuals increased with age and appeared to persist throughout life. Ovarian asymmetry was apparent, with the left ovary displaying higher rates of ovulation, and a maximum of 19 corpora recorded for a 24-year-old female. The estimated ovulation and annual pregnancy rates for mature females were 0.39 year^-1 and 30%, respectively. Conception and calving occurred year-round, with a weak seasonal increase observed in late austral spring and early austral summer. As these data did not clearly show whether seasonality was present, the gestation, lactation, and resting periods were calculated as either 12.6 or 12.8 months based on the presence/absence of seasonality, respectively. Similarly, calving interval ranged from 3.15 to 3.2 years, depending upon whether seasonality was considered. The estimated LSM of the New Zealand population aligns with other populations globally, although the estimated ASM is younger by approximately 6 months. Other reproductive parameters align with Northern Hemisphere populations, although demonstrate variation, which may reflect adaptations to local conditions such as water temperature and prey availability. As the species is subject to anthropogenic impacts including pollution and bycatch, we suggest our findings be used as a baseline with which to monitor trends in population parameters.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s00227-022-04139-3.

Bacterial microbiomes from mucus and breath of southern resident killer whales (Orcinus orca)

Opportunities to assess odontocete health are restricted due to their limited time at the surface, relatively quick movements and large geographic ranges. For endangered populations such as the southern resident killer whales (SKRWs) of the northeast Pacific Ocean, taking advantage of non-invasive samples such as expelled mucus and exhaled breath is appealing. Over the past 12 years, such samples were collected, providing a chance to analyse and assess their bacterial microbiomes using amplicon sequencing. Based on operational taxonomic units, microbiome communities from SRKW and transient killer whales showed little overlap between mucus, breath and seawater from SRKW habitats and six bacterial phyla were prominent in expelled mucus but not in seawater. Mollicutes and Fusobacteria were common and abundant in mucus, but not in breath or seawater, suggesting these bacterial classes may be normal constituents of the SRKW microbiome. Out of 134 bacterial families detected, 24 were unique to breath and mucus, including higher abundances of Burkholderiaceae, Moraxellaceae and Chitinophagaceae. Although there were multiple bacterial genera in breath or mucus that include pathogenic species (e.g. Campylobacter, Hemophilus, Treponema), the presence of these bacteria is not necessarily evidence of disease or infection. Future emphasis on genotyping mucus samples to the individual animal will allow further assessment in the context of that animal's history, including body condition index and prior contaminants burden. This study is the first to examine expelled mucus from cetaceans for microbiomes and demonstrates the value of analysing these types of non-invasive samples.

Polluted porpoises: Generational transfer of organic contaminants in harbour porpoises from the southern North Sea

Persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and hexachlorobenzene (HCB), bioaccumulate in marine ecosystems. Top predators contain high levels of POPs in their lipid-rich tissues, which may result in adverse effects on their reproductive, immune and endocrine functions. Harbour porpoises (Phocoena phocoena) are among the smallest of cetaceans and live under high metabolic demand, making them particularly vulnerable to environmental pressures. Using samples from individuals of all maturity classes and sexes stranded along the southern North Sea (n = 121), we show the generational transfer of PCBs, PBDEs and HCB from adults to foetuses. Porpoise placentas contained 1.3-8.2 mg/kg lipid weight (lw) Sum-17PCB, <dl-0.08 mg/kg lw Sum-17PBDE and 0.14-0.16 mg/kg lw HCB, which were similar to concentrations in foetus blubber. Contaminant levels increased significantly after birth through suckling. Milk samples contained 0.20-33.8 mg/kg lw Sum-17PCB, 0.002-0.51 mg/kg lw Sum-17PBDE and 0.03-0.21 mg/kg lw HCB. Especially lower halogenated and more toxic contaminants were transferred to calves, exposing them to high levels of contaminants early in life. Of all animals included in this study, 38.5% had PCB concentrations exceeding a threshold level for negative health effects (>9 mg/kg lw). This was particularly true for adult males (92.3% >9 mg/kg lw), while adult females had relatively low PCB levels (10.5% >9 mg/kg lw) due to offloading. Nutritional stress led to higher offloading in the milk, causing a greater potential for toxicity in calves of nutritionally stressed females. No correlation between PCB concentration and parasite infestation was detected, although the probability of a porpoise dying due to infectious disease or debilitation increased with increasing PCB concentrations. Despite current regulations to reduce pollution, these results provide further evidence of potential health effects of POPs on harbour porpoises of the southern North Sea, which may consequently increase their susceptibility to other pressures.

Maternal transfer of polychlorinated biphenyls in Pacific sand lance (Ammodytes personatus), Puget Sound, Washington

We measured polychlorinated biphenyls (PCBs) in multiple age and size classes of Pacific sand lance (Ammodytes personatus), including eggs, young-of-the year, and adults to evaluate maternal transfer as a pathway for contaminant uptake and to add to the limited information on the occurrence of PCBs in sand lance in Puget Sound. Sampling was replicated at an urban embayment (Eagle Harbor) and a state park along an open shoreline (Clayton Beach), during spring and fall. Lipid-normalized concentrations of PCBs in sand lance at Eagle Harbor were 5-11 times higher than PCB concentrations in comparable samples at Clayton Beach. This was true for every life stage and size class of sand lance, including eggs removed from females. The same trend was observed in environmental samples. In Eagle Harbor, PCB concentrations in unfiltered water (0.19 ng/L), sieved (<63 μm) nearshore bed sediments (0.78 ng/g dw) and suspended particulate matter (1.69 ng/g dw) were 2-3 times higher than equivalent samples from near Clayton Beach. Sand lance collected in the fall (buried in sediment during presumed winter dormancy) had lower lipid content and up to four times higher PCB concentrations than comparably sized fish collected in the spring (by beach seine). Lipid content was 5-8% in spring fish and was reduced in fall fish (1-3%). Male sand lance had higher PCB concentrations than comparable females. All egg samples contained PCBs, and the lipid normalized egg/female concentration ratios were close to 1 (0.87-0.96), confirming that maternal transfer of PCBs occurred, resulting in sand lance eggs and early life stages being contaminated with PCBs even before they are exposed to exogenous sources. These life stages are prey for an even wider range of species than consume adult sand lance, creating additional exposure pathways for biota and increasing the challenges for mitigation of PCBs in the food web.

Legacy and current-use toxic contaminants in Pacific sand lance (Ammodytes personatus) from Puget Sound, Washington, USA

Forage fish are primary prey for seabirds, fish and marine mammals. Contaminant transfer and biomagnification of the toxic compounds measured in this study likely contribute to elevated levels in Puget Sound, Washington, salmon and killer whale tissues that could be sufficiently high to elicit adverse effects and hamper population recovery efforts. Polychlorinated biphenyls, polybrominated diphenyl ethers, chlorinated pesticides, polycyclic aromatic hydrocarbons, alkylphenols, and chlorinated paraffins were detected in all Pacific sand lance tissue samples generally below available health effect levels. Residual polycyclic aromatic hydrocarbon tissue concentrations near a former creosote site suggest ongoing contaminant exposure. Biomagnification calculations suggest that concentrations of polychlorinated biphenyls in some forage fish could result in predator tissue concentrations exceeding effect levels. The emerging contaminants alkylphenols and chlorinated paraffins are first reported here in Puget Sound forage fish, and their frequent detection, high production volumes and endocrine-disrupting properties highlight the need for further study.

Life history and social structure as drivers of persistent organic pollutant levels and stable isotopes in Hawaiian false killer whales (Pseudorca crassidens)

False killer whales are long-lived, slow to mature, apex predators, and therefore susceptible to bioaccumulation of persistent organic pollutants (POPs). Hawaiian waters are home to three distinct populations: pelagic; Northwestern Hawaiian Islands (NWHI) insular; and main Hawaiian Islands (MHI) insular. Following a precipitous decline over recent decades, the MHI population was listed as "endangered" under the Endangered Species Act in 2012. This study assesses the risk of POP exposure to these populations by examining pollutant concentrations and ratios from blubber samples (n = 56) related to life history characteristics and MHI social clusters. Samples were analyzed for PCBs, DDTs, PBDEs, and some organochlorine pesticides. Skin samples (n = 52) were analyzed for stable isotopes δ¹³C and δ¹⁵N to gain insight into MHI false killer whale foraging ecology. Pollutant levels were similar among populations, although MHI whales had a significantly higher mean ratio of DDTs/PCBs than NWHI whales. The ∑PCB concentrations of 28 MHI individuals (68%) sampled were equal to or greater than suggested thresholds for deleterious health effects in marine mammals. The highest POP values among our samples were found in four stranded MHI animals. Eight of 24 MHI adult females have not been documented to have given birth; whether they have yet to reproduce, are reproductive senescent, or are experiencing reproductive dysfunction related to high POP exposure is unknown. Juvenile/sub-adults had significantly higher concentrations of certain contaminants than those measured in adults, and may be at greater risk of negative health effects during development. Multivariate analyses, POP ratios, and stable isotope ratios indicate varying risk of POP exposure, foraging locations and potentially prey items among MHI social clusters. Our findings provide invaluable insight into the ongoing risk POPs pose to the MHI population's viability, as well as consideration of risk for the NWHI and pelagic stocks.

High concentrations of persistent organic pollutants in adult killer whales (Orcinus orca) and a foetus stranded in Ireland

Bio-accumulation of persistent organic pollutants including polychlorinated biphenyls (PCBs), brominated flame retardants and organochlorine pesticides continue to be of major concern for marine apex predators such as killer whales. The concentrations of 16 polychlorinated biphenyls, 7 poly-brominated diphenyl ethers (PBDEs), 1 poly-brominated biphenyl (PBB) and a range of 19 organochlorine compounds (OCs) was investigated in blubber samples from a mother-foetus pair, an adult female and an adult male killer whale stranded in Ireland between 2010 and 2017. Concentrations ranged from 1.5 mg/kg to 49.3 mg/kg lipid weight and 0.04-1.2 mg/kg lipid weight for Σ16PCBs and Σ7PBDEs respectively. Concentrations of organochlorine compounds were also investigated in the male killer whale; a Σ19OC concentration of 49.4 mg/kg lipid weight was recorded. This study shows high levels of persistent organic pollutants occur in this species of whales stranded in Ireland.

Fecal stress, nutrition and reproductive hormones for monitoring environmental impacts on tigers (Panthera tigris)

Non-invasive stress and nutritional hormone analysis in relation to ecological and other biological indices have tremendous potential to address environmental disturbance impacts on wildlife health. To this end, we examined the relation between glucocorticoid (GC) and thyroid (T3) hormone indices of disturbance and nutritional stress in response to ACTH and TSH challenges in captive tigers, as well as how reproductive hormones vary by sex and reproductive condition. Glucocorticoid, thyroid, progesterone and androgen assays conducted on high-performance liquid chromatography separated fractions of biologically relevant fecal extracts revealed high cross-reactivity of these assays for their respective biologically relevant fecal hormone metabolites. Both adrenal and thyroid hormone metabolites were elevated in response to ACTH and TSH challenges. However, the adrenal and thyroid hormone responses to ACTH challenge were concurrent, whereas the adrenal response to TSH challenge was delayed relative to thyroid hormone elevation in both males and females. The concurrently elevated T3 in response to ACTH may serve to raise metabolic rate to maximize use of GC-mobilized glucose, whereas the relatively delayed GC rise following TSH challenge may be a response to glucose depletion due to increased metabolic rate associated with elevated T3. Progesterone, testosterone and androstenedione hormone metabolites were significantly elevated during gestation compared to lactation in a female monitored from conception through early lactation. Results suggest that the glucocorticoid, thyroid and reproductive hormone assays we tested can accurately measure the stress, nutrition and reproductive response from tiger feces, providing useful non-invasive tools to assess physiological responses to environmental stressors and their reproductive consequences in the wild.

Pre-oil spill baseline profiling for contaminants in Southern Resident killer whale fecal samples indicates possible exposure to vessel exhaust

The Southern Resident killer whale population (Orcinus orca) was listed as endangered in 2005 and shows little sign of recovery. Exposure to contaminants and risk of an oil spill are identified threats. Previous studies on contaminants have largely focused on legacy pollutants. Here we measure polycyclic aromatic hydrocarbons (PAHs) in whale fecal (scat) samples. PAHs are a diverse group of hazardous compounds (e.g., carcinogenic, mutagenic), and are a component of crude and refined oil as well as motor exhaust. The central finding from this study indicates low concentrations of the measured PAHs (<10 ppb, wet weight), as expected; however, PAHs were as high as 104 ppb prior to implementation of guidelines mandating increased distance between vessels and whales. While causality is unclear, the potential PAH exposure from vessels warrants continued monitoring. Historical precedent similarly emphasizes the importance of having pre-oil spill exposure data available as baseline to guide remediation goals.

Projected amplification of food web bioaccumulation of MeHg and PCBs under climate change in the Northeastern Pacific

Climate change increases exposure and bioaccumulation of pollutants in marine organisms, posing substantial ecophysiological and ecotoxicological risks. Here, we applied a trophodynamic ecosystem model to examine the bioaccumulation of organic mercury (MeHg) and polychlorinated biphenyls (PCBs) in a Northeastern Pacific marine food web under climate change. We found largely heterogeneous sensitivity in climate-pollution impacts between chemicals and trophic groups. Concentration of MeHg and PCBs in top predators, including resident killer whales, is projected to be amplified by 8 and 3%, respectively, by 2100 under a high carbon emission scenario (Representative Concentration Pathway 8.5) relative to a no-climate change control scenario. However, the level of amplification increases with higher carbon emission scenario for MeHg, but decreases for PCBs. Such idiosyncratic responses are shaped by the differences in bioaccumulation pathways between MeHg and PCBs, and the modifications of food web dynamics between different levels of climate change. Climate-induced pollutant amplification in mid-trophic level predators (Chinook salmon) are projected to be higher (~10%) than killer whales. Overall, the predicted trophic magnification factor is ten-fold higher in MeHg than in PCBs under high CO₂ emissions. This contribution highlights the importance of understanding the interactions with anthropogenic organic pollutants in assessing climate risks on marine ecosystems.

Interaction Mode and Regioselectivity in Vitamin B12-Dependent Dehalogenation of Aryl Halides by Dehalococcoides mccartyi Strain CBDB1

The bacterium Dehalococcoides, strain CBDB1, transforms aromatic halides through reductive dehalogenation. So far, however, the structures of its vitamin B₁₂-containing dehalogenases are unknown, hampering clarification of the catalytic mechanism and substrate specificity as basis for targeted remediation strategies. This study employs a quantum chemical donor-acceptor approach for the Co(I)-substrate electron transfer. Computational characterization of the substrate electron affinity at carbon-halogen bonds enables discriminating aromatic halides ready for dehalogenation by strain CBDB1 (active substrates) from nondehalogenated (inactive) counterparts with 92% accuracy, covering 86 of 93 bromobenzenes, chlorobenzenes, chlorophenols, chloroanilines, polychlorinated biphenyls, and dibenzo-p-dioxins. Moreover, experimental regioselectivity is predicted with 78% accuracy by a site-specific parameter encoding the overlap potential between the Co(I) HOMO (highest occupied molecular orbital) and the lowest-energy unoccupied sigma-symmetry substrate MO (σ*), and the observed dehalogenation pathways are rationalized with a success rate of 81%. Molecular orbital analysis reveals that the most reactive unoccupied sigma-symmetry orbital of carbon-attached halogen X (σ_C-X^*) mediates its reductive cleavage. The discussion includes predictions for untested substrates, thus providing opportunities for targeted experimental investigations. Overall, the presently introduced orbital interaction model supports the view that with bacterial strain CBDB1, an inner-sphere electron transfer from the supernucleophile B₁₂ Co(I) to the halogen substituent of the aromatic halide is likely to represent the rate-determining step of the reductive dehalogenation.

Climate change-contaminant interactions in marine food webs: Toward a conceptual framework

Climate change is reshaping the way in which contaminants move through the global environment, in large part by changing the chemistry of the oceans and affecting the physiology, health, and feeding ecology of marine biota. Climate change-associated impacts on structure and function of marine food webs, with consequent changes in contaminant transport, fate, and effects, are likely to have significant repercussions to those human populations that rely on fisheries resources for food, recreation, or culture. Published studies on climate change-contaminant interactions with a focus on food web bioaccumulation were systematically reviewed to explore how climate change and ocean acidification may impact contaminant levels in marine food webs. We propose here a conceptual framework to illustrate the impacts of climate change on contaminant accumulation in marine food webs, as well as the downstream consequences for ecosystem goods and services. The potential impacts on social and economic security for coastal communities that depend on fisheries for food are discussed. Climate change-contaminant interactions may alter the bioaccumulation of two priority contaminant classes: the fat-soluble persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), as well as the protein-binding methylmercury (MeHg). These interactions include phenomena deemed to be either climate change dominant (i.e., climate change leads to an increase in contaminant exposure) or contaminant dominant (i.e., contamination leads to an increase in climate change susceptibility). We illustrate the pathways of climate change-contaminant interactions using case studies in the Northeastern Pacific Ocean. The important role of ecological and food web modeling to inform decision-making in managing ecological and human health risks of chemical pollutants contamination under climate change is also highlighted. Finally, we identify the need to develop integrated policies that manage the ecological and socioeconomic risk of greenhouse gases and marine pollutants.

Nano- and micromotors for cleaning polluted waters: focused review on pollutant removal mechanisms

Nano- and micromotors are machines designed to self-propel and-in the process of propelling themselves-perform specialized tasks like cleaning polluted waters. These motors offer distinct advantages over conventionally static decontamination methods, owing to their ability to move around and self-mix-which heightens the interaction between their active sites and target pollutants-thus improving their speed and efficiency, which could potentially decrease treatment times and costs. In the last decade, considerable research efforts have been expended on exploring various mechanisms by which these motors can self-propel and remove pollutants, proving that the removal of oil droplets, heavy metals, and organic compounds using these synthetic motors is possible. This review highlights recent progress in the design of these nano- and micromotors for cleaning polluted waters, and gives an overview of their structure, fabrication, and propulsion methods, with a special focus on the mechanisms by which they remove pollutants-namely, either by adsorption or by degradation. A fundamental understanding of these removal mechanisms, with their attendant advantages and disadvantages, can help researchers fine-tune motor design in the future so that technical issues can be resolved before they are scaled-up for a wide variety of environmental applications.

Population growth is limited by nutritional impacts on pregnancy success in endangered Southern Resident killer whales (Orcinus orca)

The Southern Resident killer whale population (Orcinus orca) was listed as endangered in 2005 and shows little sign of recovery. These fish eating whales feed primarily on endangered Chinook salmon. Population growth is constrained by low offspring production for the number of reproductive females in the population. Lack of prey, increased toxins and vessel disturbance have been listed as potential causes of the whale’s decline, but partitioning these pressures has been difficult. We validated and applied temporal measures of progesterone and testosterone metabolites to assess occurrence, stage and health of pregnancy from genotyped killer whale feces collected using detection dogs. Thyroid and glucocorticoid hormone metabolites were measured from these same samples to assess physiological stress. These methods enabled us to assess pregnancy occurrence and failure as well as how pregnancy success was temporally impacted by nutritional and other stressors, between 2008 and 2014. Up to 69% of all detectable pregnancies were unsuccessful; of these, up to 33% failed relatively late in gestation or immediately post-partum, when the cost is especially high. Low availability of Chinook salmon appears to be an important stressor among these fish-eating whales as well as a significant cause of late pregnancy failure, including unobserved perinatal loss. However, release of lipophilic toxicants during fat metabolism in the nutritionally deprived animals may also provide a contributor to these cumulative effects. Results point to the importance of promoting Chinook salmon recovery to enhance population growth of Southern Resident killer whales. The physiological measures used in this study can also be used to monitor the success of actions aimed at promoting adaptive management of this important apex predator to the Pacific Northwest.

CYP polymorphisms and pathological conditions related to chronic exposure to organochlorine pesticides

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Organochlorine compounds (OCs) are persistent organic pollutants acting as endocrine disruptors.

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Exposure to OCs is a risk factor for several severe pathologies.

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Specific CYP polymorphisms could affect the clinical impact of OCs exposure.

The association between genetic variations in the cytochrome P450 (CYP) family genes and pathological conditions related to long-term exposure to organochlorine compounds (OCs) deserves further elucidation. OCs are persistent organic pollutants with bioaccumulative and lipophilic characteristics. They can act as endocrine disruptors and perturb cellular mechanisms. Prolonged exposure to OCs has been associated with different pathological manifestations. CYP genes are responsible for transcribing enzymes essential in xenobiotic metabolism. Therefore, polymorphisms in these genetic sequences a. alter the metabolic pathways, b. induce false cellular responses, and c. may provoke pathological conditions. The main aim of this review is to define the interaction between parameters a, b and c at a mechanistic/molecular level, with references in clinical cases.

Obesity, Persistent Organic Pollutants and Related Health Problems

The present review aims to delve into persistent organic pollutants (POPs) , as xenobiotics, in correlation to human health. POPs exhibit a group of common characteristics, including lipophilicity, persistence to decomposition and bioaccumulation in tissues. POPs have been thoroughly studied by former researchers, as they offer a particular interest in the elucidation of metabolic, endocrine and immune perturbation caused by their synergy with intracellular mechanisms. Herein particular focus is attributed to the relationship of POPs with obesity provocation. Obesity nowadays receives epidemic dimensions, as its prevalence elevates in an exponential degree. POPs-induced obesity rotates around interfering in metabolic and endocrinal procedures and interacting with peroxisome-proliferator and retinoic receptors. Moreover, polymorphisms in CYP gene families exert a negative result, as they incapacitate detoxification of POPs. Obesity could be deemed as a multidimensional condition, as various factors interact to lead to an obesogenic result. Therefore, concomitant disorders may occur, from mild to lethal, and get intensified due to POPs exposure. POPs exact function mechanisms remain rather enigmatic, thus further investigation should be prospectively performed, for a more lucid picture of this issue, and, consequently for the establishment of alternative solutions.