A bioassessment approach for mid-continent great rivers: the Upper Mississippi, Missouri, and Ohio (USA).

The objectives of the Environmental Monitoring and Assessment Program for Great River Ecosystems (EMAP-GRE) are to (1) develop and demonstrate, in collaboration with states, an assessment program yielding spatially unbiased estimates of the condition of mid-continent great rivers; (2) evaluate environmental indicators for assessing great rivers; and (3) assess the current condition of selected great river resources. The purpose of this paper is to describe EMAP-GRE using examples based on data collected in 2004-2006 with emphasis on an approach to determining reference conditions. EMAP-GRE includes the Upper Mississippi River, the Missouri River, and the Ohio River. Indicators include biotic assemblages (fish, macroinvertebrates, plankton, algae), water chemistry, and aquatic and riparian physical habitat. Reference strata (river reaches for which a single reference expectation is appropriate) were determined by ordination of the fish assemblage and examination of spatial variation in environmental variables. Least disturbed condition of fish assemblages for reference strata was determined by empirical modeling in which we related fish assemblage metrics to a multimetric stressor gradient. We inferred least disturbed condition from the y-intercept, the predicted condition when stress was least. Thresholds for dividing the resource into management-relevant condition classes for biotic indicators were derived using predicted least disturbed condition to set the upper bound on the least disturbed condition class. Also discussed are the outputs of EMAP-GRE, including the assessment document, multimetric indices of condition, and unbiased data supporting state and tribal Clean Water Act reporting, adaptive management, and river restoration.

An open-label study of a functional opioid kappa antagonist in the treatment of opioid dependence.

Several lines of evidence, including the well-established observation that kappa opiate agonists produce dysphoria and psychotomimetic effects in humans, suggest that dysfunction of the endogenous kappa opioid system may contribute to opioid and cocaine addiction. The objective of this open-label study was to determine the effectiveness of a functional kappa antagonist as a treatment for opioid dependence. This was accomplished by combining a partial mu agonist/kappa antagonist (buprenorphine, 4 mg, sublingual) with a mu antagonist (naltrexone, 50 mg by mouth), theoretically leaving kappa antagonism as the major medication effect. Subjects were treatment-seeking heroin-dependent (as per Diagnostic and Statistical Manual of Mental Disorders, 4th ed.) men (41 +/- 7 years old; 19 +/- 8 years heroin use) eligible for methadone maintenance. After inpatient detoxification and a naloxone-challenge test to verify that they were not physically dependent on opioids, subjects received naltrexone. Starting on the fourth day, patients also received liquid buprenorphine. All patients received medication at the clinic 6 days per week and a full program of psychosocial treatment. The major endpoints of the study were: pupil diameter to determine if the mu agonist effects of buprenorphine were blocked by naltrexone, urine toxicology, and retention in treatment. Five patients (33%) completed the 3-month study. Four were abstinent from opioids and cocaine for the entire study, and one was abstinent from opioids and cocaine for the last 9 weeks. Six subjects dropped out due to either minor side effects or disliking the sensation of sublingual buprenorphine. There were no significant changes in pupillary diameter. The positive response to treatment exceeds that expected from naltrexone alone (90% dropout). These promising results suggest that controlled studies of this medication combination should be conducted.

The effects of elevated metals on benthic community metabolism in a Rocky Mountain stream.

The effects of elevated metals (dissolved Zn, Mn and/or Fe) in a Rocky Mountain stream were assessed using measures of primary productivity, community respiration and water-column toxicity. Primary productivity was measured as rates of O2 evolution from natural substrates incubated in situ in closed chambers. Oxygen depletion within these chambers, when incubated in the dark, provided estimates of periphyton community respiration. Sediment community respiration on fine-grained sediments, collected and composited along each stream study reach, was measured on-site by incubating these sediments in closed chambers and measuring O2 depletion. Toxicity was measured as percent mortality of Ceriodaphnia dubia during 48 h acute tests. Gross (GPP) and net primary productivity (NPP) decreased significantly with increasing metal concentrations, from 10.88 +/- 1.46 g O2 m(-2) day(-1) to 0.83 +/- 0.20 g O2 m(-2) day(-1) and 9.85 +/- 1.43 g O2 m(-2) day(-1) to 0.81 +/- 0.20 g O2 m(-2) day(-1), respectively for the reference and most impacted site. Community respiration (CR) declined from 0.65 +/- 0.08 g O2 m(-2) day(-1) to 0.02 +/- 0.01 g O2 m(-2) day(-1) with increasing metal concentrations. Sediment community respiration (SCR) decreased from 0.26 +/- 0.02 g O2 m(-2) day(-1) to 0.01 +/- 0.01 g O2 m(-2) day(-1) at these same sites. Ceriodaphnia dubia mortality increased from 0% at the reference site to 95 +/- 5% at the most impacted sites. Net daily metabolism, quantum yield and assimilation ratio all decreased with increasing metal concentrations, suggesting that both autotrophic and heterotrophic components of the periphyton community were impaired. Overall, functional measures were able to discern sites receiving greater metal impacts from less-impacted sites, with combinations of dissolved metals explaining between 25 and 92% of the variance in the regression models. Using these regression models we were able to calculate lethal and inhibition concentrations of dissolved Zn in the Eagle River. The lethal concentration (LC50) of Zn for Ceriodaphnia dubia is 123 mg liter(-1). The concentrations of Zn which inhibited respiration (IC50) were 177 mg liter(-1) for CR and 199 mg liter(-1) for SCR. These results indicate functional measures may be as sensitive to metal concentrations as acute toxicity tests.