Despite its vast size and ecological and economic importance, the deep sea is among the least understood ecosystems on Earth. While much remains to be discovered, researchers have established that the deep sea is being exposed to numerous anthropogenic factors including chemical pollution. Persistent organic pollutants (POPs), defined by their persistence in the environment, bioaccumulation, and toxicity, are continually discharged and transported into the deep sea despite efforts to ban or reduce their production under global and regional conventions. Here, we provide the first evidence of these POPs in sediment and biota in the Pacific abyssal plain, an area currently targeted for deep-sea mining. Sediment and fish tissue (Coryphaenoides sp., a deep-ocean predator and scavenger fish) collected from two sites in the eastern Clarion-Clipperton Zone of the Pacific abyssal plain were tested for three POPs: polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and per- and polyfluoroalkyl substances (PFAS). Similarities between the sites in PCB congener concentrations suggested that PCBs were distributed evenly over the region. Conversely, higher variability in PBDE congener concentrations and PFAS concentrations from the same sites suggested that these chemicals had more patchy distributions across the region. Sediment PFAS were especially variable, detected at a high concentration (1.5 ng/g wet weight) in only one of five samples but measured in all fish muscle samples at levels comparable to some freshwater ecosystems. Results suggest that raining particulates (e.g., particulate organic matter and microplastics) dominate vertical transport of PCBs, resulting in more uniform distribution, while episodic events such as carrion-fall and vertically migrating species may drive PFAS transport processes resulting in patchy spatial distributions and differences in scavenging biota versus sediment. Unintentional PCBs (e.g., pigment components) comprised a large proportion of total PCBs in sediment and muscle tissue, suggesting that unregulated PCB releases are accumulating in the deep Pacific Ocean.

The white perch ( Morone americana ) is an abundant estuarine teleost in eastern North America, with its commercial and trophic importance creating a need for fecundity and recruitment data. In this study, we reevaluated the fecundity of subpopulations of white perch in Chesapeake Bay. Stereological sampling methods were used to determine if environmental changes in the Chesapeake Bay watershed over the last 60 years have altered average fecundity of this species. These methods were compared with automated gravimetric methods to determine the efficacy of using stereological fecundity sampling for white perch. The results of using both methods were statistically the same, as indicated by a Lin's concordance correlation coefficient of 0.98 and a favorable distribution on Bland-Altman plots. After the stereological methods were validated, archival histological samples from the Choptank River subestuary were evaluated for fecundity over a 4- year period of sampling. Results indicate that fecundity of white perch has been reasonably unchanged in the river system, with an average estimated fecundity of 69,379 oocytes per fish. These findings indicate the resiliency of the reproduction of white perch in mesohaline Chesapeake Bay, despite widespread environmental change.

Remedial investigations of sites contaminated with legacy pollutants like polychlorinated biphenyls (PCBs) have traditionally focused on mapping sediment contamination to develop a site conceptual model and select remedy options. Ignoring dissolved concentrations that drive transport and bioaccumulation often leads to an incomplete assessment of ongoing inputs to the water column and overestimation of potential effectiveness of sediment remediation. Here, we demonstrate the utility of codeployment of passive equilibrium samplers and freshwater mussels as dual lines of evidence to identify ongoing sources of PCBs from eight main tributaries of the Anacostia River in Washington, DC, that has been historically polluted from industrial and other human activities. The freely dissolved PCB concentrations measured using passive samplers tracked well with the accumulation in mussels and allowed predictions of biouptake within a factor of 2 for total PCBs and a factor of 4 for most congeners. One tributary was identified as the primary source of PCBs to the water column and became a focus of additional ongoing investigations. Codeployment of passive samplers and mussels provides strong lines of evidence to refine site conceptual models and identify ongoing sources critical to control to achieve river water quality standards and reduce bioaccumulation in the aquatic food web.

OBJECTIVE:Modeling of fecundity with allometric, nutritional, and environmental covariates has increased sensitivity of reproductive metrics in many fish species. In estuaries with heavy anthropogenic influence, resident species often experience sublethal health impacts because of increased stress, which can include increases in gonadal pathology, intersex, or potential reproductive failure. This study models the fecundity of the estuarine species White Perch Morone americana in response to health parameters identified as signals of habitat stress, including gross pathology presentation, nutritional condition, and disease presence.METHODS:Subpopulation fecundity in the Choptank River (Maryland) of the Chesapeake Bay was estimated using stereological fecundity sampling methods and modeled using information-theoretic approaches of model selection. Nutritional and health parameters identified through health assessment techniques, specific somatic indices, and disease presence were selected as covariates.RESULT:Nutrition demonstrated limited influence on model fit as compared to models with only conventional allometric variables such as weight and length. Of the health variables, gross pathology and somatic indices showed minimal influence on selection, but mycobacterial infection, a chronic condition in the Chesapeake Bay among temperate basses, showed measurable influence. Models with mycobacteriosis included were 40 times more likely the best fit when compared to models with only allometric parameters.CONCLUSION:Whether this has a region-wide influence on all subpopulations will require further research and sampling of the magnitude of mycobacteriosis infection.

Adverse reproductive effects associated with gonadal intersex among freshwater fish could hold considerable implications for population sustainability. Presence of testicular oocytes (TO) is the most common form of intersex and is widespread among centrarchids (sunfishes) of North America and other freshwater teleosts. Placing TO within the toxicological context of adverse outcome pathways (AOPs) to assess ecological risk is a priority for ecotoxicologists due to the association of TO with harmful chemical exposure and adverse reproductive effects in some cases. However, key event relationships between EDC exposure, incidence of TO, and apical outcomes have yet to be fully elucidated - in part due to a lack of knowledge of relationships between intersex gonad physiology and fish health. Understanding the physiological status of intersex fish is critical to assess ecological risk, understand mechanisms of induction, and to establish biomarkers of intersex in fish. In the present study, features of gonad metabolite profiles associated with TO in largemouth bass (LMB, Micropterus salmoides) from an impoundment in Georgia (USA) were determined using GC-MS-based metabolomics. Clinical blood biochemical screens were used to evaluate markers of fish health associated with TO. Results suggest that physiological changes in energy expenditure as well as relatively 'feminized' gonad lipid and protein metabolism may be related to the occurrence of TO in male LMB, and highlight the need to understand relationships between intersex and physical stressors such as elevated temperature and hypoxia. These results provide novel insight to AOPs associated with TO and identify candidate analytes for biomarker discovery.

Microplastics are a complex group of ubiquitous environmental contaminants of emerging concern. These particles degrade slowly, release plasticizers, and can be transferred between trophic levels. In aquatic systems, they have been identified suspended in the water column, along shorelines, and within sediment. However, the abundance and distribution of microplastics in vegetated wetlands, which are transitional ecosystems between terrestrial and aquatic environments, are poorly understood. Here we describe the spatial distribution of soil microplastics in habitats of varying vegetation density in an urban tidal wetland. Samples were wet-sieved, organic matter was oxidized using hydrogen peroxide, and microplastics separated under a dissecting microscope, counted, and weighed. A fraction (n = 175) were analyzed via FTIR for validation. Positive microplastics identification was 81%-93%. Dominant polymers were polystyrene (29%) and polyethylene and synthetic rubber (both 8%). Average microplastic number to a 5-cm depth (23,200 ± 2,500 m-2 or 1,270 ± 150 kg-1) varied between habitat types, where mudflat, channel edge, and drift line habitats all had significantly more total microplastics than the interior of dense stands of vegetation, suggesting that emergent wetland plants are a highly effective filter of microplastics. Microfibers were about eight times as abundant as microfragments, and fibers and fragments differed in their distribution patterns, with microfibers most abundant in vegetation-free mudflats and microfragments in vegetated channel edges. Our results demonstrate that vegetated wetlands are important locations for microplastic accumulation and that wetland vegetation and hydrodynamics affect spatial distribution of microplastics between habitats.

Progestins are utilized as a component of human contraceptives, and commonly enter the environment via wastewater treatment plant effluent. Certain progestins activate fish androgen receptors and cause decreases in fecundity and masculinization of females. We used a nest acquisition assay and computer-assisted sperm analysis to examine the effects of levonorgestrel on male fathead minnow (Pimephales promelas) reproductive fitness. Males were exposed to 0, 10, or 100 ng/L levonorgestrel for 14 d. Combinations of a control male and a male from one of the treatments were placed into a competitive nesting assay, and the time each male spent holding the nest and time spent exhibiting aggressive behaviors were analyzed at 48 h postexposure. Semen samples were analyzed for total motility, straight-line velocity, curvilinear velocity, average path velocity, linearity, beat cross frequency, and wobble at 0, 30, 60, 90, and 120 s postactivation. Males exposed to either 10 or 100 ng/L of levonorgestrel exhibited increased nest acquisition success and lower levels of aggression compared with control-control pairings, as well as decreases in multiple sperm motion characteristics. Our results suggest that further research is required to ascertain the effects of levonorgestrel on male gamete quality and reproductive behaviors. Environ Toxicol Chem 2018;37:1131-1137. © 2017 SETAC.

Although the complexity of contaminant mixtures in sediments can confound the identification of causative agents of adverse biological response, understanding the contaminant(s) of primary concern at impacted sites is critical to sound environmental management and remediation. In the present study, a stock mixture of 18 polycyclic aromatic hydrocarbon (PAH) compounds was prepared to reflect the variety and relative proportions of PAHs measured in surface sediment samples collected from discrete areas of a historically contaminated industrial estuary. This site‐specific PAH stock mixture was spiked into nontoxic in‐system and out‐of‐system field‐collected reference sediments in dilution series spanning the range of previously measured total PAH concentrations from the region. Spiked sediments were evaluated in 10‐d Leptocheirus plumulosus tests to determine whether toxicity in laboratory‐created PAH concentrations was similar to the toxicity found in field‐collected samples with equivalent PAH concentrations. The results show that toxicity of contaminated sediments was not explained by PAH exposure, while indicating that toxicity in spiked in‐system (fine grain, high total organic carbon [TOC]) and out‐of‐system (course grain, low TOC) sediments was better explained by porewater PAH concentrations, measured using an antibody‐based biosensor that quantified 3‐ to 5‐ring PAHs, than total sediment PAH concentrations. The study demonstrates the application of site‐specific spiking experiments to evaluate sediment toxicity at sites with complex mixtures of multiple contaminant classes and the utility of the PAH biosensor for rapid sediment‐independent porewater PAH analysis. Environ Toxicol Chem 2018;37:893–902. © 2017 SETAC

The identification of myriad of chemicals in the environment that mimic hormones and affect the endocrine functions of exposed organism is a daunting analytical challenge for environmental scientists and engineers. Many of these endocrine disrupting chemicals (EDCs) are present at very low concentrations in the aquatic systems, but yet affect the metabolic, developmental, and reproductive functions in exposed fish and wildlife. Vitellogenin (VTG) protein is a widely used biomarker in fish for assessing exposure to EDCs, and is commonly measured using species-specific immunochemical techniques. In this study, we developed a liquid chromatography tandem mass spectrometry (LC-MS/MS) method that can measure common peptides from digested VTG in multiple fish species. In the initial experiments using high resolution mass spectrometry, two peptides (ALHPELR and FIELIQLLR) were identified as common fragments in the digested VTG protein isolated from three different fish species (Pimephales promelas, Micropterus salmoides, and Fundulus heteroclitus). Then, a quantitative analysis using LC-MS/MS under selected reaction monitoring mode was developed for the detection of these two peptides in trypsin-digested plasma from female fish (positive control), estrogen-exposed male fish (test sample), and unexposed male fish (negative control) using two of the same species used for identifying the common peptides (P. promelas, and M. salmoides) and one new species (Ameiurus nebulosus) that was not included during the selection of peptides. Results from this study demonstrate the potential of LC-MS/MS as an effective cross-species method to detect VTG in fish, which can be an alternative analytical technique for assessing endocrine disruption in multiple fish species.

Poultry manure contains free and conjugated forms of the natural estrogens 17β-estradiol and estrone, which can be transported to receiving waters via runoff when land-applied. Previous studies have demonstrated estrogens in runoff from poultry manure-amended fields but have not tracked changes in estrogenicity within this water over time. Microbial conversion of conjugated estrogens (a major portion of water-extractable estrogens) to parent forms may result in temporary increases in estrogenicity in natural water bodies. The present study created 80-L batches of simulated poultry manure runoff, which were investigated over 10 d for estrogenicity by bioluminescent yeast estrogen screen assay and fathead minnow () vitellogenin induction model. The efficacy of different compost conditions (in-vessel aeration ± turning, and piling) on reduction/elimination of aqueously extractable estrogens in poultry manure was also investigated. Results indicate 3- to 10-fold increases in estrogenicity in various poultry manure mixtures during 10-d observations. Estrogenicity returned to low levels in postcompost treatments but remained elevated in the precompost treatment. Aerated compost resulted in >75% reductions in initial, peak, and 10-d mean estrogenicity in aqueous mixtures (0.3, 0.8, and 0.5 ng 17β-estradiol equivalents [EEQ] L, respectively) compared with the precompost mixture (1.4, 4.8, and 2.1 ng EEQ L, respectively). Estrogenicity was significantly higher in the aqueous extract from the piled treatment than the aerated treatment, and 10-d exposure of male fish to the piled treatment resulted in statistically significant vitellogenin induction. Collectively, our results suggest a need to investigate estrogenicity in surface waters for several days after receiving manure-influenced runoff.

Intersex in wild fish populations has received considerable attention in the scientific literature and public media. Conventional detection of testicular oocytes, the presence of immature oocytes within testis of male fish, commonly employs transverse sectioning of excised testis and is lethal. The present study used a nonlethal laparoscopic technique to collect biopsies of testis from black bass, entering the body cavity via the genital pore. Detection of testicular oocytes was compared between biopsy and conventional methods using 79 smallmouth bass (Micropterus dolomieu) from 8 sites and 68 largemouth bass (Micropterus salmoides) from 4 sites. The 2 methods performed similarly at sites where testicular oocyte severity was moderate or high (6 of 8 smallmouth bass sites), whereas transverse sectioning resulted in superior testicular oocyte detection at sites where severity was low (2 of 8 smallmouth bass sites and all 4 largemouth bass sites). In smallmouth bass, testicular oocyte prevalence by transverse and biopsy methods was strongly correlated across sites (r(2) = 0.81) and severity reported by enumeration of testicular oocytes was moderately correlated across sites (r(2) = 0.59). Survival of a subset of largemouth bass (n = 20) to 28 d after laparoscopic surgery was 90%. The present research indicates that laparoscopy may be useful for monitoring the prevalence and severity of testicular oocytes in Micropterus species, particularly when lethal sampling is precluded. (C) 2016 SETAC

The synthetic progestin levonorgestrel is commonly utilized in human oral contraceptives. It enters the environment as a component of wastewater treatment plant effluent, and has been measured at low ng/L concentrations in surface waters. It has been shown to activate fish androgen receptors, causing the physical masculinization of females, changes in reproductive behavior, and decreases in fecundity. In the present study, the effects of levonorgestrel exposure on early-stage oogenesis in the fathead minnow (Pimephales promelas) was examined. Adult females were exposed to 0, 10, or 100ng/L levonorgestrel for 14 d using a flow-through exposure system. The ovaries from each female were then removed via dissection and weighed for gonadosomatic index (GSI) calculations, and oocytes from one lobe preserved in Serra's fixative. Total numbers of late-stage vitellogenic oocytes exhibiting a germinal vesicle were then quantified. In a second exposure, blood plasma samples were collected from adult females and analyzed for vitellogenin concentrations using enzyme-linked immunosorbent assay. Females exposed to both concentrations of levonorgestrel developed male secondary sexual characteristics in a dose-dependent manner, and ovaries contained significantly fewer late stage oocytes. Exposure to 100ng/L of levonorgestrel resulted in decreased GSI and blood plasma vitellogenin concentrations. The results suggest that female exposure to levonorgestrel alone may have profound effects on reproduction in progestin-contaminated environments. Environ Toxicol Chem 2017;36:3299-3304. (c) 2017 SETAC

Municipal biosolids contain natural estrogens, e.g., 17 beta-estradiol (E2) and estrone (E1), and synthetic estrogens, e.g., 17 alpha-ethinylestradiol (EE2), which can be transported to receiving waters via runoff when land-applied as fertilizer. Previous studies have investigated estrogens in runoff from biosolids-amended fields but have not tracked changes in estrogenicity within this water over time. Microbial conversion of conjugated estrogens (a major portion of water-extractable estrogens) to parent forms may result in temporary increases in estrogenicity in natural water bodies. The present study measured aqueously extractable estrogens in simulated runoff generated using biosolids sourced from four municipal wastewater treatment facilities in Maryland. Estrogen analytes (E2 and E1) were quantified over 10 d periods in 80 L static simulated runoff mixtures (0.5 g biosolids L-1) by LC-MS/MS, and estrogenic activity was estimated using the in vitro bioluminescent yeast estrogen screen (BLYES) assay and the in vivo fathead minnow (Pimephales promelas) vitellogenin (VTG) induction model. The effectiveness of pilot-scale in-vessel, aerated, turned (IVAT) composting to reduce or eliminate aqueously extractable estrogens in biosolids was also investigated. On arrival, only one of four biosolids had environmentally meaningful levels of aqueously extractable estrogens. Results indicate that estrogens/ estrogenicity increased >6.5-fold during the first 6 d in an aqueous extract generated with that sample, as indicated both by BLYES quantitation of estrogenicity (0.8 to 5.6 ng EEQ L-1) and LC-MS/MS quantitation of estrone (13.8 to 93.0 ng L-1). Results also indicate that IVAT composting was effective at reducing or eliminating aqueously extractible estrogens in that biosolids sample. This study demonstrates the need for low-level detection of estrogens/ estrogenicity in complex environmental media and validates the benefits of in vitro screening assays and in vivo fish models as complementary sensitive tools for environmental monitoring.

Ionophores are the second top selling class of antimicrobials used in food-producing animals in the United States. In chickens, ionophores are used as feed additives to control coccidiosis; up to 80% of administered ionophores are excreted in the litter. Because poultry litter is commonly used to fertilize agricultural fields, ionophore residues in litter have become contaminants of emerging concern. This study aims to develop a liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to quantify ionophores, and identify their transformation products (TPs) in poultry litter after on-farm pilot scale composting. The validation parameters of the optimized method showed good accuracy, ranging from 71 to 119% recovery and relative standard deviation (precision) of <= 19% at three different concentration levels (10, 50 and 100 mu g/kg). Monensin, salinomycin and narasin, were detected in the poultry litter samples prior to composting at 290.0 +/- 40, 426 +/- 46, and 3113 +/- 318 mu g kg(-1), respectively. This study also aims to investigate the effect of different composting conditions on the removal of ionophores, such as the effect of turning or aeration. Results revealed a 13-68% reduction in ionophore concentrations after 150 d of composting, depending on whether the compost was aerated, turned, or subjected to a combination of both aeration and turning. Three transformation products and one metabolite of ionophores were identified in the composted litter using high-resolution liquid chromatography with quadrupole time-of-flight mass spectrometry (LC-QToF/MS). (C) 2016 Elsevier Ltd. All rights reserved.

Roxarsone has been used extensively in the broiler chicken industry. We reviewed the environmental concerns of this usage. To summarize, arsenic added to poultry feed as roxarsone ends up in poultry litter. Fresh litter contains predominately roxarsone, whereas aged litter contains predominately inorganic arsenic. Soil arsenic concentrations from long-term poultry litter applications can exceed Maryland arsenic soil background remediation standards. Due to continued soil accumulation, arsenic-amended litter use as fertilizer is thought to be unsustainable. Surface-applied roxarsone-amended litter does not influence deep aquifer arsenic concentrations but is transported as inorganic arsenic to receiving waters and very shallow groundwater after precipitation. Arsenic in some receiving waters and sediments from agriculturally dominated watersheds have levels above established criteria. Arsenic in fish and shellfish is mostly organic. Phosphorus-based nutrient management will tend to limit PL application rates in areas that have over-applied phosphorus relative to crop needs, resulting in decreased rates of arsenic application and accumulation. Despite most arsenic in surface soils being tightly bound, as surface soils become more enriched in arsenic, the potential for downward movement increases but is limited in most soils due to the high capacity for binding of arsenic to clay minerals and oxides of iron and aluminum in subsoil horizons. In 2012, Maryland passed a law banning the use of arsenic additives except nitarsone in poultry feed. In 2013, the USFDA withdrew approval of roxarsone, carbarsone, and arsanilic but is reviewing nitarsone.