Examining historical mercury sources in the Saint Louis River estuary: How legacy contamination influences biological mercury levels in Great Lakes coastal regions.

Industrial chemical contamination within coastal regions of the Great Lakes can pose serious risks to wetland habitat and offshore fisheries, often resulting in fish consumption advisories that directly affect human and wildlife health. Mercury (Hg) is a contaminant of concern in many of these highly urbanized and industrialized coastal regions, one of which is the Saint Louis River estuary (SLRE), the second largest tributary to Lake Superior. The SLRE has legacy Hg contamination that drives high Hg concentrations within sediments, but it is unclear whether legacy-derived Hg actively cycles within the food web. To understand the relative contributions of legacy versus contemporary Hg sources in coastal zones, Hg, carbon, and nitrogen stable isotope ratios were measured in sediments and food webs of SLRE and the Bad River, an estuarine reference site. Hg stable isotope values revealed that legacy contamination of Hg was widespread and heterogeneously distributed in sediments of SLRE, even in areas lacking industrial Hg sources. Similar isotope values were found in benthic invertebrates, riparian spiders, and prey fish from SLRE, confirming legacy Hg reaches the SLRE food web. Direct comparison of prey fish from SLRE and the Bad River confirmed that Hg isotope differences between the sites were not attributable to fractionation associated with rapid Hg bioaccumulation at estuarine mouths, but due to the presence of industrial Hg within SLRE. The Hg stable isotope values of game fish in both estuaries were dependent on fish migration and diet within the estuaries and extending into Lake Superior. These results indicate that Hg from legacy contamination is actively cycling within the SLRE food web and, through migration, this Hg also extends into Lake Superior via game fish. Understanding sources and the movement of Hg within the estuarine food web better informs restoration strategies for other impaired Great Lakes coastal zones.

Dreissena veligers in western Lake Superior - inference from new low-density detection.

The notion that Lake Superior proper is inhospitable to dreissenid mussel survival has been challenged by recent finds on shipwrecks and rocky reefs in the Apostle Islands region. Motivated by concerns surrounding these finds, we conducted an intensive sampling campaign of Apostle Islands waters in 2017 to understand Dreissena prevalence and distribution. The 100-site effort combined random and targeted sites and collected zooplankton, benthos, video, environmental DNA, and supporting water quality data. We did not find settled Dreissena in any video footage or benthos samples, and quantitative PCR applied to eDNA samples was negative for Dreissena. Dreissena veligers were found in almost half the zooplankton samples but at orders of magnitude lower densities than reported from other Laurentian Great Lakes. Veligers were most prevalent around the western islands and associated with shallower depths and slightly higher phosphorus and chlorophyll, but did not spatially match known (still very localized) settled Dreissena colonies. This is the first study to conduct veliger-targeted sampling in western Lake Superior and the first to report consistent detection of veligers there. We speculate that these Apostle Islands veligers are not a new locally-spawned component of the zooplankton community, but instead are transported from an established population in the St. Louis River estuary (~100 km away) by longshore currents; i.e., low-density propagule pressure that may have been present for years. Small-mesh zooplankton data collected along a gradient from the Apostle Islands to the St. Louis River estuary and enumerated with thorough veliger searching would help elucidate these alternatives.

Evaluating Evidence on Intermediate Outcomes: Considerations for Groups Making Healthcare Recommendations.

INTRODUCTION: Groups making recommendations need evidence about whether preventive services improve health outcomes (HOs). When such evidence is not available, groups may choose to evaluate evidence about effects on intermediate outcomes (IOs) and the link between IOs and HOs. This paper aims to describe considerations for assessing the evidence linking changes in IOs to changes in HOs. METHODS: Working definitions of IOs, HOs, and other outcomes were developed. All current U.S. Preventive Services Task Force (USPSTF) recommendations through April 2016 were examined to identify how evidence of the IO-HO link was gathered and the criteria that appeared to be used to determine the adequacy of the evidence. Methods of other expert and recommendation-making groups were also examined. RESULTS: Forty-four USPSTF recommendations involved a relevant IO-HO link. The approaches used most commonly to gather evidence about the link were selected review (19 of 44, 43%) and systematic review (12 of 44, 27%). Some key considerations when assessing the adequacy of evidence about the IO-HO link include adjustment for confounding, proximity of the IO to the HO in the causal pathway, and independence of IO-HO relationship from specific treatments. CONCLUSIONS: Considerations were identified for recommendation-making groups to use when gathering and assessing the adequacy of evidence about the IO-HO link. Using a standard set of written principles could improve the transparency of assessments of the IO-HO link, especially if used together with judgment in a reasoned conjecture and refutation process. Ideally, the process would result in an estimate of the magnitude of change in HOs that is expected for specified changes in IOs.

Do psychological harms result from being labelled with an unexpected diagnosis of abdominal aortic aneurysm or prostate cancer through screening? A systematic review.

OBJECTIVE: A potential psychological harm of screening is unexpected diagnosis-labelling. We need to know the frequency and severity of this harm to make informed decisions about screening. We asked whether current evidence allows an estimate of any psychological harm of labelling. As case studies, we used two conditions for which screening is common: prostate cancer (PCa) and abdominal aortic aneurysm (AAA). DESIGN: Systematic review with narrative synthesis. DATA SOURCES AND ELIGIBILITY CRITERIA: We searched the English language literature in PubMed, PsychINFO and Cumulative Index of Nursing and Allied Health Literature (CINAHL) for research of any design published between 1 January 2002 and 23 January 2017 that provided valid data about the psychological state of people recently diagnosed with early stage PCa or AAA. Two authors independently used explicit criteria to review and critically appraise all studies for bias, applicability and the extent to which it provided evidence about the frequency and severity of harm from labelling. RESULTS: 35 quantitative studies (30 of PCa and 5 of AAA) met our criteria, 17 (48.6%) of which showed possible or definite psychological harm from labelling. None of these studies, however, had either appropriate measures or relevant comparisons to estimate the frequency and severity of psychological harm. Four PCa and three AAA qualitative studies all showed clear evidence of at least moderate psychological harm from labelling. Seven population-based studies found increased suicide in patients recently diagnosed with PCa. CONCLUSIONS: Although qualitative and population-based studies show that at least moderate psychological harm due to screening for PCa and AAA does occur, the current quantitative evidence is insufficient to allow a more precise estimation of frequency and severity. More sensitive measures and improved research designs are needed to fully characterise this harm. In the meantime, clinicians and recommendation panels should be aware of the occurrence of this harm.

Fish tissue lipid-C:N relationships for correcting δ(13) C values and estimating lipid content in aquatic food-web studies.

RATIONALE: Normalizing δ(13) C values of animal tissue for lipid content is necessary to accurately interpret food-web relationships from stable isotope analysis. To reduce the effort and expense associated with chemical extraction of lipids, various studies have tested arithmetic mass balance to mathematically normalize δ(13) C values for lipid content; however, the approach assumes that lipid content is related to the tissue C:N ratio. METHODS: We evaluated two commonly used models for estimating tissue lipid content based on C:N ratio (a mass balance model and a stoichiometric model) by comparing model predictions to measure the lipid content of white muscle tissue. We then determined the effect of lipid model choice on δ(13) C values normalized using arithmetic mass balance. To do so, we used a collection of fish from Lake Superior spanning a wide range in lipid content (5% to 73% lipid). RESULTS: We found that the lipid content was positively related to the bulk muscle tissue C:N ratio. The two different lipid models produced similar estimates of lipid content based on tissue C:N, within 6% for tissue C:N values <7. Normalizing δ(13) C values using an arithmetic mass-balance equation based on either model yielded similar results, with a small bias (<1‰) compared with results based on chemical extraction. CONCLUSIONS: Among-species consistency in the relationship between fish muscle tissue C:N ratio and lipid content supports the application of arithmetic mass balance to normalize δ(13) C values for lipid content. The uncertainty associated with both lipid extraction quality and choice of model parameters constrains the achievable precision of normalized δ(13) C values to about ±1.0‰.

Human influences on water quality in Great Lakes coastal wetlands.

A better understanding of relationships between human activities and water chemistry is needed to identify and manage sources of anthropogenic stress in Great Lakes coastal wetlands. The objective of the study described in this article was to characterize relationships between water chemistry and multiple classes of human activity (agriculture, population and development, point source pollution, and atmospheric deposition). We also evaluated the influence of geomorphology and biogeographic factors on stressor-water quality relationships. We collected water chemistry data from 98 coastal wetlands distributed along the United States shoreline of the Laurentian Great Lakes and GIS-based stressor data from the associated drainage basin to examine stressor-water quality relationships. The sampling captured broad ranges (1.5-2 orders of magnitude) in total phosphorus (TP), total nitrogen (TN), dissolved inorganic nitrogen (DIN), total suspended solids (TSS), chlorophyll a (Chl a), and chloride; concentrations were strongly correlated with stressor metrics. Hierarchical partitioning and all-subsets regression analyses were used to evaluate the independent influence of different stressor classes on water quality and to identify best predictive models. Results showed that all categories of stress influenced water quality and that the relative influence of different classes of disturbance varied among water quality parameters. Chloride exhibited the strongest relationships with stressors followed in order by TN, Chl a, TP, TSS, and DIN. In general, coarse scale classification of wetlands by morphology (three wetland classes: riverine, protected, open coastal) and biogeography (two ecoprovinces: Eastern Broadleaf Forest [EBF] and Laurentian Mixed Forest [LMF]) did not improve predictive models. This study provides strong evidence of the link between water chemistry and human stress in Great Lakes coastal wetlands and can be used to inform management efforts to improve water quality in Great Lakes coastal ecosystems.

The role for vitamin B-6 as treatment for depression: a systematic review.

BACKGROUND: Major depression is the leading cause of disability worldwide, and among the 10 most frequent indications for using alternative medicine therapies, especially dietary supplements. OBJECTIVE: To assess the evidence evaluating vitamin B-6 supplementation as treatment for depression. METHODS: Medline, Psychinfo, AMED, and Cochrane Controlled Trials Register were searched from database inception through September 2001. All randomized controlled trials, controlled clinical trials, intervention studies, case-control studies, reviews, and case reports examining the evidence behind vitamin B-6 in depression among humans were selected. No limits were placed for demographics or co-morbidities. Only English language papers were abstracted and assessed for trial quality. Two abstractors independently evaluated each study, then reconciled findings. As data were available, between group treatment effect size was noted or, as needed, calculated. When studies reported outcome effects using multiple measures, data were abstracted to permit the greatest possible comparisons among papers. RESULTS: Ten articles met inclusion criteria; three reviews, one case report, five RCTs, and one intervention study. There was no common outcome measure among all studies, eliminating opportunity for direct comparison of effect sizes. As an alternate means of comparison, effects were plotted as they related to the null hypothesis. CONCLUSION: Viewed as a whole, meaningful treatment effect of vitamin B-6 for depression in general was not apparent. However, examination of papers addressing depression in pre-menopausal women only, reveals a consistent message about the value of using vitamin B-6 supplementation. Further study of vitamin B-6 as independent and adjuvant therapy for hormone related depression in women is indicated.