Chemical pollution can degrade aquatic ecosystems. Chinook salmon in contaminated habitats are vulnerable to health impacts from toxic exposures. Few studies have been conducted on adverse health outcomes associated with current levels and mixtures of contaminants. Fewer still address effects specific to the juvenile life-stage of salmonids. The present study evaluated contaminant-related effects from dietary exposure to environmentally relevant concentrations and mixture profiles in juvenile Chinook salmon from industrialized waterways in the U.S. Pacific Northwest using two end points: growth assessment and disease susceptibility. The dose and chemical proportions were reconstituted based on environmental sampling and analysis using the stomach contents of juvenile Chinook salmon recently collected from contaminated, industrialized waterways. Groups of fish were fed a mixture with fixed proportions of 10 polychlorinated biphenyls (PCBs), 3 dichlorodiphenyltrichloroethanes (DDTs), and 13 polycyclic aromatic hydrocarbons (PAHs) at five concentrations for 35 days. These contaminant compounds were selected because of elevated concentrations and the widespread presence in sediments throughout industrialized waterways. Fork length and otolith microstructural growth indicators were significantly reduced in fish fed environmentally relevant concentrations of these contaminants. In addition, contaminant-exposed Chinook salmon were more susceptible to disease during controlled challenges with the pathogen Aeromonas salmonicida. Our results indicate that dietary exposure to contaminants impairs growth and immune function in juvenile Chinook salmon, thereby highlighting that current environmental exposure to chemicals of potential management concern threatens the viability of exposed salmon.
The Lower Duwamish River is a highly industrialized waterway flowing into the densely urbanized Puget Sound waterfront of Seattle, Washington, USA. The river has been profoundly altered from its natural state following more than a century of channelization, recurrent dredging, shoreline armoring, and pollution discharges. As part of a Natural Resource Damage Assessment addressing historical pollution at three designated Superfund sites (i.e., the assessment area), juvenile Pacific staghorn sculpin (Leptocottus armatus) were sampled throughout the lower river in order to evaluate injury from exposure to polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDTs), and butyltins (BTs). Sculpin live in close association with the river sediments within and upriver of the assessment area. Fish were collected for analysis of contaminant concentrations in composited whole bodies and stomach contents, as well as individual fish health metrics including daily somatic growth rates measured from otoliths. Sediment contaminant concentrations were also measured at sites near to fishing locations. Fish growth rates varied from 0.65 to 1.05 mm/day, and were significantly lower at unremediated downriver sites compared to upriver and remediated locations. Sculpin growth rates were negatively correlated with concentrations of PCBs in fish bodies, PAHs in stomach contents, as well as PCBs, DDTs and PAHs in sediment. Mixed effects models for whole-body and stomach content contaminants showed positive correlations between growth rate and water temperature. Temperature was not a significant confounding variable for the relationship between growth rate and sediment contaminants. Overall, these results show that juvenile sculpin are harmed by contaminant exposure in the Lower Duwamish River. Furthermore, this study demonstrates the utility of using paired biological and chemical indicators of pollutant-induced injury in a resident fish to inform a complex Natural Resource Damage Assessment and associated restoration efforts.
The industrial waterway in Portland Harbor, Oregon, is a migration corridor for a distinct population segment of Chinook Salmon (Upper Willamette River) currently protected by the U.S. Endangered Species Act. Juveniles are exposed to a suite of contaminants during outmigration including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and dichlorodiphenyltrichloroethanes. We collected natural origin subyearling Chinook salmon from sites in and around the industrial harbor to evaluate growth (otolith microstructural analysis) in relation to measured chemical concentrations in tissue. A reduced growth rate was associated with higher tissue contaminant concentrations, particularly mixtures represented by PAHs and certain PCBs, which were elevated in juvenile Chinook collected throughout sites within Portland Harbor relative to those captured upstream. First-year growth is an established predictor of individual survival and eventual reproductive success in Chinook salmon. Therefore, our results indicate that legacy pollution may be limiting the population abundance of threatened Willamette River Chinook salmon, and future habitat remediation or restoration actions may benefit ongoing species recovery efforts.
A quality improvement project was delivered by a federally qualified health center to improve patient access to psychiatric services. The effort was supported by training and technical assistance provided by the American Psychiatric Association Support and Alignment Network. Over a 3-year period, the collaborative care model (CoCM) and other integrated consultative strategies were implemented. As a result, the waitlist was reduced from 350 patients to 1 patient. The use of the CoCM and other integrated care strategies was successful in eliminating a psychiatric service waitlist in this primary care setting.
Back to table of contents Previous article Next article Psychiatry and Integrated CareFull AccessCollaborative Care as a Way to Stave Off BurnoutJohn Kern,M.D.John Kern,Search for more papers by this authorM.D.Published Online:17 Jul 2018https://doi.org/10.1176/appi.pn.2018.7b12AbstractJohn Kern, M.D., is a clinical professor in the Department of Psychiatry and Behavioral Sciences at the University of Washington and a faculty member at the AIMS Center. He has been involved with the APA Transforming Clinical Practice Initiative grant, which supports collaborative care training of psychiatrists and primary care providers. Jürgen Unützer, M.D., M.P.H., is a professor and chair of psychiatry and behavioral sciences at the University of Washington and founder of the AIMS Center, dedicated to “advancing integrated mental health solutions.”Addressing the problem of professional burnout has become a pressing topic in psychiatry as we all try to achieve a work-life balance that is satisfying, enriching, and sustainable. This month’s author, John Kern, M.D., found that working as the consulting psychiatrist for a collaborative care program helped stave off burnout and allowed him to reach his clinical and personal goals. —Jürgen Unützer, M.D., M.P.H.I worked in a CMHC for 27 years. My residency training didn’t prepare me to consider that work with the most seriously ill people could be a skill worth recognizing. This took time for me to understand.First, I found myself impressed and humbled by staff, usually case managers, who dedicated themselves at little recompense to the care of patients with severe illness. Then, over the years, there was the growth of relationships with my most difficult patients, born of long and difficult work together. Finally, I began to read the literature on poor health outcomes among people with severe and persistent mental illness. I began to feel that the primary duty of our agency was to treat the most severely affected.I began to try to reorganize psychiatric services at my center to do a better job of making care accessible and effective for our most seriously affected patients.When we started to make it our business to improve the accessibility of our services and the actual measured clinical outcomes of our patients and to demonstrate our value to them, the job of working as a psychiatrist got a lot harder. I wanted my docs to work with me to figure out how to see more patients and keep track of more factors, like physical health status. This is good work, but at the end of the day, it is still more work.It was about this same time that the electronic medical record (EMR) appeared. I thought that this would be a good thing—it would feed us information about our patients to help us make diagnostic and treatment decisions. It would be possible to actually read my colleagues’ (previously illegible) notes—what a novelty!It did not occur to me that these innovations and attitudinal changes, pretty much all of which I was completely on board for and which I tried to hasten into practice, would help transform psychiatric practice into something that many find exhausting and unrewarding!As Anita Everett, M.D., then president of APA, wrote in a column in the July 13, 2017, Psychiatric News: “We know that things like excessive productivity quotas, limits on the time that we can spend with each patient, and documentation requirements are major sources of dissatisfaction for physicians. Some stressors that adversely affect psychiatrists specifically include limited resources, high work demands, and patient violence.”So I find myself torn. On the one hand, I have an exciting sense of mission: to improve the care of those who need care the most; on the other hand, I recognize the toll that changing practice takes on me and my psychiatric staff.What can help make this better? As Anita wrote later in her column, “…experiencing collegiality, fairness, and respect leaves us feeling more satisfied with our work.”In my personal work life, I started to spend a half day to a full day’s worth of time directing and working as the consultant psychiatrist for a collaborative care program in a nearby Federally Qualified Health Center. I found that this offered opportunities for some of the practice features that have been shown to reduce burnout:Novelty: I hadn’t worked in a primary care setting since I was a medical student, and rubbing elbows with the staff in this highly interactive and stimulating milieu was eye-opening, to say the least.Collegiality: I formed new and enjoyable working relationships with the primary care providers and care managers with whom I worked.Respect: The expertise a psychiatrist can offer to a primary care setting can seem basic to the psychiatrist, but is usually extremely appreciated.Autonomy and control over work: At least in the early stages—and most collaborative care programs are yet in their early stages—there is wide latitude to create workflows and procedures in partnership with primary care providers.Less friction with EMRs: Most collaborative care programs require much more limited documentation than does standard psychiatry, and often there is team assistance with this. There is no going back to the “good old days” of psychiatric practice—this model left out too many people who need our care. Nonetheless, the most important aspect of traditional psychiatric care that is sustaining and affirming is, of course, the face-to-face encounter with the patient and family. By no means do I suggest that this be abandoned; there is no substitute for expert specialty psychiatry.I do suggest that work in a team-based model, of which the collaborative care model is one, may serve as a mitigating practice against burnout as psychiatrists find a way to meet their clinical and personal goals in a challenging and fluid practice environment. ■ ISSUES NewArchived
To evaluate health effects associated with consumption of fish contaminated with polychlorinated biphenyls (PCBs) from the upper Hudson River, farm-raised mink were fed diets containing fish collected from the river. Endpoints assessed included adult reproductive performance, offspring growth and mortality, and organ mass and pathology of adults and their offspring. Scat samples were collected from adult males at the time of necropsy and from adult females just prior to whelping. Scat samples were analyzed for PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). The present study provides the results of these analyses and compares Sigma PCB and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalent (TEQ) concentrations in scat with dietary and hepatic concentrations associated with effects reported previously. Dry weight concentrations of Sigma PCBs and Sigma TEQs in scat generally increased with dietary concentration and reflected corresponding increases in hepatic concentrations of Sigma PCBs and Sigma TEQs. Maternal concentrations of Sigma PCBs in scat expressed on a dry, wet, and lipid weight basis predicted to result in 50% kit mortality (LC50) were 1.0, 0.30, and 12 mu g Sigma PCBs/g. Concentrations of Sigma PCBs in scat expressed on a dry, wet, and lipid weight basis predicted to result in 50% incidence of a previously reported jaw lesion (EC50) were 1.7, 0.48, and 24 mu g Sigma PCBs/g in adult females and 2.5, 0.87, and 19 mu g Sigma PCBs/g in adult males. (C) 2017 SETAC
The American Psychiatric Association Integrated Care Workgroup recently convened an expert panel charged with addressing the role of psychiatry in improving the physical health of persons with serious mental illness. The group reviewed the peer-reviewed and gray literature and developed a set of recommendations grounded in this review. This column summarizes the panel's primary findings and recommendations to key stakeholders, including clinicians, health care organizations, researchers, and policy makers.
Remedial decision making at large contaminated sediment sites with bioaccumulative contaminants often relies on complex mechanistic models to forecast future concentrations and compare remedial alternatives. Remedial decision-making for the Hudson River PCBs Superfund site involved predictions of future levels of PCBs in Upper Hudson River (UHR) and Lower Hudson River (LHR) fish. This study applied model emulation to evaluate the impact of updated sediment concentrations on the original mechanistic model projections of time to reach risk-based target thresholds in fish in the LHR under Monitored Natural Attenuation (MNA) and the selected dredging remedy. The model emulation approach used a combination of nonlinear and linear regression models to estimate UHR water PCBs as a function of UHR sediment PCBs and to estimate fish concentrations in the LHR as a function of UHR water PCBs, respectively. Model emulation captured temporal changes in sediment, water, and fish PCBs predicted by the mechanistic model over the emulation period. The emulated model, using updated sediment concentrations and a revised estimate of recovery rate, matched the trend in annual monitoring data for white perch and largemouth bass in the LHR between 1997 and 2014. Our best predictions based on the emulated model indicate that the projected time to reach fish tissue risk-based thresholds in the LHR will take decades longer than the original mechanistic model projections.
Polychlorinated biphenyl (PCB) concentrations reported in preferred prey and blubber of bottlenose dolphins from the Turtle-Brunswick River estuary (Georgia, USA) suggest the potential for adverse effects. However, PCBs in Turtle-Brunswick River estuary dolphins are primarily derived from Aroclor 1268, and predicting toxic effects of Aroclor 1268 is uncertain because of the mixture's unique composition and associated physiochemical characteristics. These differences suggest that toxicity benchmarks for other PCB mixtures may not be relevant to dolphins exposed to Aroclor 1268. American mink (Neovison vison) were used as a surrogate model for cetaceans to characterize mechanisms of action associated with Aroclor 1268 exposure. Mink share similarities in phylogeny and life history with cetaceans and are characteristically sensitive to PCBs, making them an attractive surrogate species for marine mammals in ecotoxicity studies. Adult female mink and a subsequent F1 generation were exposed to Aroclor 1268 through diet, and effects on enzyme induction, histopathology, thyroid hormone regulation, hematology, organ weights, and body condition index were compared to a negative control and a 3,3,4,4,5-pentachlorobiphenyl (PCB 126)-positive control. Aroclor 1268 dietary exposure concentrations ranged from 1.8 mu g/g wet weight to 29 mu g/g wet weight. Anemia, hypothyroidism, and hepatomegaly were observed in mink exposed to Aroclor 1268 beyond various dietary thresholds. Cytochrome P450 induction and squamous epithelial proliferation jaw lesions were low in Aroclor 1268 treatments relative to the positive control. Differences in enzyme induction and the development of squamous epithelial proliferation jaw lesions between Aroclor 1268 treatments and the positive control, coupled with effects observed in Aroclor 1268 treatments not observed in the positive control, indicate that mechanisms additional to the aryl hydrocarbon receptor-mediated pathway are associated with Aroclor 1268 exposure. (c) 2015 SETAC
Polychlorinated biphenyls (PCBs) from the commercial mixture Aroclor 1268 were historically released into the Turtle-Brunswick River estuary (southeastern Georgia, USA) from industrial operations. Sum PCBs (ΣPCBs) in blubber samples from Turtle-Brunswick River estuary bottlenose dolphins (Tursiops truncatus) have been reported at concentrations more than 10-fold higher than those observed in dolphins from adjacent regional estuaries. Given that toxicity data specific to Aroclor 1268 and applicable to marine mammals are limited, predicting the toxic effects of Aroclor 1268 in dolphins is uncertain, particularly because of its unique congener profile and associated physiochemical characteristics compared with other PCB mixtures. American mink (Neovison vison) were chosen as a surrogate model for cetaceans to develop marine mammalian PCB toxicity benchmarks. Mink are a suitable surrogate species for cetaceans in toxicity studies because of similarities in diet and taxonomic class, and a characteristic sensitivity to PCBs provides a potential safety factor when using mink toxicology data for cross-species extrapolations. Effects of dietary exposure to Aroclor 1268 on reproduction, growth, and mortality in mink were compared with both a negative control and a positive control (3,3',4,4',5-pentachlorobiphenyl, PCB 126). Aroclor 1268 dietary ΣPCB concentrations ranged from 1.8 µg/g feed wet weight to 29 µg/g feed wet weight. Whelp success was unaffected by Aroclor 1268 exposure at any level. Treatment mean litter size, kit growth, and kit survival were adversely affected relative to the negative control at dietary ΣPCB concentrations of 10.6 µg/g feed wet weight and greater.
Background: Feed intake and gain are economically important traits in beef production. The rumen wall interacts with feed, microbial populations, and fermentation products important to cattle nutrition. As such, it is likely to be a critical component in the beef steer's ability to utilize feedstuffs efficiently. To identify genes associated with steer feed intake and body weight gain traits, and to gain an understanding of molecules and pathways involved in feed intake and utilization, RNA sequencing (RNA-Seq) was performed on rumen papillae from 16 steers with variation in gain and feed intake. Four steers were chosen from each of the four Cartesian quadrants for gain x feed intake and used to generate individual RNA-Seq libraries.Results: Normalized read counts from all of the mapped reads from each of the four groups of animals were individually compared to the other three groups. In addition, differentially expressed genes (DEGs) between animals with high and low gain, as well as high and low intake were also evaluated. A total of 931 genes were differentially expressed in the analyses of the individual groups. Eighty-nine genes were differentially expressed between high and low gain animals; and sixty-nine were differentially expressed in high versus low intake animals. Several of the genes identified in this study have been previously associated with feed efficiency. Among those are KLK10, IRX3, COL1A1, CRELD2, HDAC10, IFITM3, and VIM.Conclusions: Many of the genes identified in this study are involved with immune function, inflammation, apoptosis, cell growth/proliferation, nutrient transport, and metabolic pathways and may be important predictors of feed intake and gain in beef cattle. Published by Elsevier B.V.
Documenting successful remediation of polychlorinated biphenyl (PCB)-contaminated sediments is limited; potentially due to inadequate monitoring methods, complexities associated with the environment, and selected remedial techniques. At some sites, absence of appropriate baseline and postremoval monitoring limits proper evaluation of remedial efficacy. Accurate interpretation of interactions between media, space, time, species, lipid content, and remedial technique requires robust study design and data. This article presents baseline and postremoval data documenting reduced PCB concentrations in fish tissue, surface water, and sediment in response to the US Environmental Protection Agency (USEPA) time-critical removal action (TCRA) that was conducted at the former Bryant Mill Pond (BMP) on Portage Creek in Kalamazoo, Michigan. The BMP is part of an operable unit (OU) within the Allied Paper, Inc./Portage Creek/Kalamazoo River Superfund Site. PCBs discharged to the creek as a byproduct of carbonless copy paper recycling are the primary contaminant of concern. Paper waste residuals commonly appear as gray to light gray clays in river sediments and floodplain soils. The cleanup criterion was 10mg/kg, with a residual PCB concentration goal of 1mg/kg. Because the PCB-containing waste is (generally) associated with readily visible light gray clay, excavation of all visibly contaminated current or formerly impounded sediment served as a surrogate for the cleanup criteria and goal. Sediment was wet excavated and backfilled after diversion of the creek. After confirmation that PCB concentrations met cleanup criteria, the stream was diverted to the excavated side, and excavation and backfilling were completed. Overall, 146000 cubic yards of material including PCB-contaminated sediments were removed from the BMP. The long-term monitoring (LTM) program implemented by the Michigan Department of Environmental Quality (MDEQ), and historic data from a variety of sources (federal, state, and local agencies and responsible parties) provided data demonstrating TCRA effectiveness. Before TCRA, surface sediment PCB concentration in instream and formerly inundated sediment combined was 83mg/kg (with a maximum of 700mg/kg). Instream sediments that are more representative of fish exposures had a pre-TCRA surface weighted average concentration (SWAC) of 27mg/kg. The post-TCRA SWAC for instream and floodplain sediments combined was 0.26mg/kg. Average surface water concentrations at the downstream end of the BMP were reduced from 0.11 mu g/L pre-TCRA to 0.0025 mu g/L post-TCRA. Tissue samples for adult carp fillets decreased from 4mg/kg pre-TCRA to 0.26mg/kg post-TCRA; whole body white suckers from 3mg/kg pre-TCRA to 0.1mg/kg post-TCRA; whole body channel catfish from 39mg/kg-L pre-TCRA to 2.6mg/kg-L post-TCRA. Concentrations of PCBs in 2 species of resident fish (carp and white suckers), caged channel catfish, surface water, and sediment were reduced by over 1 order of magnitude within 1 year of completion, substantively accelerating natural recovery processes. A slight increase in PCB concentration was observed in both whole body suckers and adult carp fillets in the second monitoring period post-TCRA; however, these concentrations are still near an order of magnitude less than pre-TCRA concentrations and appear to be currently stable or on a slight downward trend. Integr Environ Assess Manag 2015;11:161-170. (c) 2014 SETAC
The effects of feeding farm‐raised mink (Mustela vison) diets containing polychlorinated biphenyl (PCB)–contaminated fish from the upper Hudson River (New York, USA) on adult reproductive performance and kit growth and mortality were evaluated. Diets contained 2.5 to 20% Hudson River fish, providing 0.72 to 6.1 µg ∑PCBs/g feed (4.8–38 pg toxic equivalents [TEQWHO 2005]/g feed). The percentage of stillborn kits per litter was significantly increased by dietary concentrations of 4.5 µg ∑PCBs/g feed (28 pg TEQWHO 2005/g feed) and greater. All offspring exposed to dietary concentrations of 4.5 and 6.1 µg ∑PCBs/g feed (28 and 38 pg TEQWHO 2005/g feed) died by 10 weeks of age, and all offspring exposed to 1.5 and 2.8 µg ∑PCBs/g feed (10 and 18 pg TEQWHO 2005/g feed) died by 31 weeks of age, leaving juveniles in the control and 0.72 µg ∑PCBs/g feed (0.41‐ and 4.8 pg TEQWHO 2005/g feed) groups only. The dietary concentration predicted to result in 20% kit mortality (LC20) at six weeks of age was 0.34 µg ∑PCBs/g feed (2.6 pg TEQWHO 2005/g feed). The corresponding maternal hepatic concentration was 0.80 µg ∑PCBs/g liver, wet weight (13 pg TEQWHO 2005/g liver, wet wt). Mink residing in the upper Hudson River would be expected to consume species of fish that contain an average of 4.0 µg ∑PCBs/g tissue. Thus, a daily diet composed of less than 10% Hudson River fish could provide a dietary concentration of ∑PCBs that resulted in 20% kit mortality in the present study. Environ. Toxicol. Chem. 2013;32:780–793. © 2013 SETAC
The authors evaluated effects of feeding ranch mink (Mustela vison) diets containing polychlorinated biphenyl (PCB)-contaminated fish from the upper Hudson River (New York, USA) on adult and offspring organ mass and pathology. Diets contained 2.5 to 20% Hudson River fish, providing 0.72 to 6.1 µg ΣPCBs/g feed (4.8-38 pg toxic equivalents [TEQWHO 2005 ]/g feed). Absolute thyroid and adrenal gland masses were increased in adult females and 31-week-old juveniles, respectively, and absolute liver and heart masses were decreased in six-week-old kits exposed to dietary PCBs. Dietary concentrations of 0.72 µg ΣPCBs/g feed (4.8 pg TEQWHO 2005 /g feed) and greater induced mandibular and maxillary squamous epithelial proliferation in adult animals. The dietary concentration of ΣPCBs predicted to result in 20% incidence of the jaw lesion (EC20) was 2.3 µg ΣPCBs/g feed (15 pg TEQWHO 2005 /g feed), and the hepatic concentration was 2.8 µg ΣPCBs/g liver (89 pg TEQWHO 2005 /g liver). The EC20 values were greater than the dietary and hepatic concentrations predicted to result in a 20% increase in kit mortality (LC20) at six weeks of age (0.34 µg ΣPCBs/g feed or 2.6 pg TEQWHO 2005 /g feed and 0.80 µg ΣPCBs/g liver or 13 pg TEQWHO 2005 /g liver). However, the EC20 values reflect exposure of adults to PCBs for approximately six months, and the LC20 values reflect exposure of offspring from conception onward.
OBJECTIVE:Integration of general medical and mental health services is a growing priority for safety-net providers. The authors describe a project that established a one-year learning collaborative focused on integration of services between community health centers (CHCs) and community mental health centers (CMHCs). Specific targets were treatment for general medical and psychiatric symptoms related to depression, bipolar disorder, alcohol use disorders, and metabolic syndrome.METHODS:This observational study used mixed methods. Quantitative measures included 15 patient-level health indicators, practice self-assessment of resources and support for chronic disease self-management, and participant satisfaction.RESULTS:Sixteen CHC-CMHC pairs were selected for the learning collaborative series. One pair dropped out because of personnel turnover. All teams increased capacity on one or more patient health indicators. CHCs scored higher than CMHCs on support for chronic disease self-management. Participation in the learning collaborative increased self-assessment scores for CHCs and CMHCs. Participant satisfaction was high. Observations by faculty indicate that quality improvement challenges included tracking patient-level outcomes, workforce issues, and cross-agency communication.CONCLUSIONS:Even though numerous systemic barriers were encountered, the findings support existing literature indicating that the learning collaborative is a viable quality improvement approach for enhancing integration of general medical and mental health services between CHCs and CMHCs. Real-world implementation of evidence-based guidelines presents challenges often absent in research. Technical resources and support, a stable workforce with adequate training, and adequate opportunities for collaborator communications are particular challenges for integrating behavioral and general medical services across CHCs and CMHCs.
Diseases are increasing in marine ecosystems, and these increases have been attributed to a number of environmental factors including climate change, pollution, and overfishing. However, many studies pool disease prevalence into taxonomic groups, disregarding host-species composition when comparing sites or assessing environmental impacts on patterns of disease presence. We used simulated data under a known environmental effect to assess the ability of standard statistical methods (binomial and linear regression, ANOVA) to detect a significant environmental effect on pooled disease prevalence with varying species abundance distributions and relative susceptibilities to disease. When one species was more susceptible to a disease and both species only partially overlapped in their distributions, models tended to produce a greater number of false positives (Type I error). Differences in disease risk between regions or along an environmental gradient tended to be underestimated, or, even in the wrong direction, when highly susceptible taxa had reduced abundances in impacted sites, a situation likely to be common in nature. Including relative abundance as an additional variable in regressions improved model accuracy, but tended to be conservative, producing more false negatives (Type II error) when species abundance was strongly correlated with the environmental effect. An analysis of field data on bleaching from the Florida Keys, FL, USA, affirmed general results of model simulations. Investigators should be cautious of underlying assumptions about species similarity in susceptibility and species composition when interpreting pooled data on disease risk.
Using established protocols and thereby applying a systematic approach to monitoring roadside revegetation projects can increase the quality of monitoring information and reduce the amount of field and office time. We present a guide to developing a simple monitoring plan, selecting monitoring protocols, collecting and analyzing data, and presenting findings in a monitoring report. The approach is demonstrated in a case study. Also included is a brief description of a monitoring protocol we developed that uses a digital camera and a computer program called the Cover Monitoring Assistant (CMA) to facilitate a quick assessment of soil and vegetative cover information from digital photographs.
Dose-response relationships for aquatic organisms have been developed for numerous contaminants using external media exposures (water and sediment). Dose-response relationships based on internal concentrations (tissue residues) are limited. The present study reports Hg dose-response curves for early life stage and juvenile or adult fish based on published tissue-residue toxicity studies. These curves rely primarily on endpoints that can be directly related to mortality, such as survival, reproductive success, and lethal developmental abnormalities. These lethality-equivalent endpoints were linked using the common metric of injury. Uncertainties and potential applications of this mercury dose-response curve are discussed. Major uncertainties include lab to field extrapolations, biological endpoints selected by investigators, interspecific extrapolations, and the paucity of published early life stage residue (dose)-response information. To the extent this curve is based exclusively on laboratory toxicity tests and does not consider other potentially sensitive and ecologically important biological endpoints (e.g., growth and behavior), the magnitude of the adverse effects predicted by the curve may be underestimated.