Avoidance and toxicity responses of fish to intermittent chlorination

The ability of fish to actively avoid concentrations of chlorine in a steep, horizontal, laboratory-controlled gradient was found to be species-specific and dependent upon the acclimation temperature, water quality conditions, and the type of chlorine residual tested. Comparison of behavioral avoidances with the results from bioassays using some form of intermittent chlorination, as reported in the literature, indicated that LC₅₀ concentrations (levels that cause the mortality of half the test individuals in a designated time period) usually exceeded avoidance threshold concentrations.This chlorine avoidance study, which was carried out in a field laboratory that utilized New River water for holding and testing procedures, was located at the Glen Lyn power plant in southwestern Virginia. Two basic types of avoidance trials were employed, TRC (total residual chlorine) and chloramine (CRC) exposures. The TRC trials contained variable amounts of free (FRC) and combined residual chlorine (CRC) depending upon water quality, while in chloramine trials, the TRC exposure was mainly comprised of monochloramine with little or no FRC. The first significant avoidance in TRC trials for several fish species tested, varied from 0.05 mg/1 for coho salmon (Oncorhynchus kisutch) to 0.40 for channel catfish (Ictalurus punctatus). Low levels of hypochlorous acid (HOCl), which are considered to be a potentially toxic constituent of FRC, appeared to consistently influence the avoidance response. Initial avoidance concentrations to HOCl ranged from 0.01–0.02 mg/1 for coho salmon to 0.04–0.12 mg/1 for channel catfish, depending upon acclimation temperatures tested. The pH in river water was more influential than temperature in controlling the amount of HOCl present within the FRC at each TRC exposure. Avoidance responses by fish to CRC concentrations were either equal to or greater than TRC exposures and were dependent upon the ammonia-N content. Chloramine and FRC (specifically the HOCl fraction) have been reported to have different mechanisms of toxicity, which offered possible explanations for the differences observed in avoidance behavior. Chlorine residuals discharged from the Glen Lyn power plant in previous years have exceeded the LC₅₀ values reported for many species, although no major fish kills from chlorine have been documented. Behavioral avoidance responses by fish to potentially lethal chlorinated discharges in aquatic receiving systems may be a major mechanism of these populations in adapting to or interacting within these industrially influenced environments.     

EFFECTS OF NITRATE AND PHOSPHATE CONCENTRATION ON NATURAL AQUATIC BACTERIAL POPULATIONS1

ABSTRACT: Natural aquatic bacterial populations in three streams located at the Savannah River Project, Aiken, S.C. have been studied in relation to the effects of ambient temperatures, dissolved River Project, Aiken, oxygen (DO), nitrate and phosphate concentrations. ³ 3 This work was supported in part by Contract #AT (38–1–824) with the U.S. Atomic Energy Commission, and was done in part in connection with AEC Contract #AT (07–2)–1.
Samples collected at monthly intervals for a period of one year from each system, were plated in duplicate at each of two dilutions on 1/4 strength Standard Plate Count Agar (Difco). After incubation at 25±1 °C for four days, total colony forming units, percent chromagens, and number of colony types (diversity) were determined and colonies were picked for identification. Temperatures were generally equal in two of the streams throughout the year, being lowest in Upper Three Runs (U3R) and Tirns Branch (TB), and highest in the Ash Basin System (ABS). DO content did not vary appreciably between the streams. Nitrates and phosphates were lowest in U3R, next lowest in TB, higher in the last station in ABS, and highest in the ash basin per se. Total colony forming units were highest in the ash basin, whereas chromagen percentage and diversity were highest in the last station in ABS. Results of these studies indicate that high nitrates and phosphates, in the absence of high organic carbon concentrations, have little, if any detrimental effect on the stability of natural aquatic bacterial populations.     

Evaluation of Ecologically Relevant Bioassays for a Lotic System impacted by a Coal-mine effluent, using Isonychia

Many studies investigating the ecotoxicological impacts of industrial effluents on fresh-water biota utilize standardized test species such as the daphnids, Ceriodaphnia dubia, Daphnia magna, and the fathead minnow, Pimephales promelas. Such species may not be the most predictive or ecologically relevant gauges of the responses of instream benthic macroinvertebrates to certain stressors, such as total dissolved solids. An indigenous species approach should be adopted, using a sensitive benthic collector-filterer following development of practical laboratory bioassays. In the Leading Creek Watershed (southeast Ohio), an aggregated approximately 99% reduction in mean mayfly abundance for all impacted sites was observed below a coal-mine effluent with mean specific conductivity (SC) of 8,109 (7,750-8,750) microS cm(-1). The mayfly, Isonychia, was exposed for 7-days to a simulation of this effluent, in lotic microcosms. Based on lowest observable adverse effect concentrations, Isonychia survival was a more sensitive endpoint to SC (1,562 microS cm(-1)) than were 7-day C. dubia survival and fecundity (3,730 microS cm(-1)). Isonychia molting, a potentially more sensitive endpoint, was also examined. Using traditional test species to assess discharges to surface water alone may not adequately protect benthic macroinvertebrate assemblages in systems impaired by discharges high in SC.     

Groundwater-surface water interaction and its role on TCE groundwater plume attenuation

A field investigation of a TCE plume in a surficial sand aquifer shows that groundwater-surface water interactions strongly influence apparent plume attenuation. At the site, a former industrial facility in Connecticut, depth-discrete monitoring along three cross-sections (transects) perpendicular to groundwater flow shows a persistent VOC plume extending 700 m from the DNAPL source zone to a mid-size river. Maximum TCE concentrations along a transect 280 m from the source were in the 1000s of microg/L with minimal degradation products. Beyond this, the land surface drops abruptly to a lower terrace where a shallow pond and small streams occur. Two transects along the lower terrace, one midway between the facility and river just downgradient of the pond and one along the edge of the river, give the appearance that the plume has strongly attenuated. At the river, maximum TCE concentrations in the 10s of microg/L and similar levels of its degradation product cis-DCE show direct plume discharge from groundwater to the river is negligible. Although degradation plays a role in the strong plume attenuation, the major attenuation factor is partial groundwater plume discharge to surface water (i.e. the pond and small streams), where some mass loss occurs via water-air exchange. Groundwater and stream mass discharge estimates show that more than half of the plume mass discharge crossing the first transect, before surface water interactions occur, reaches the river directly via streamflow, although river concentrations were below detection due to dilution. This study shows that groundwater and surface water concentration measurements together provide greater confidence in identifying and quantifying natural attenuation processes at this site, rather than groundwater measurements alone.     

Industrial sources influence air concentrations of hydrogen sulfide and sulfur dioxide in rural areas of western Canada

A survey of monthly average concentrations of sulfur dioxide (SO2) and hydrogen sulfide (H2S) at rural locations in western Canada (provinces of Alberta, British Columbia, and Saskatchewan) was conducted in 2001-2002, as part of an epidemiological study of the effects of oil and gas industry emissions on the health of cattle. Repeated measurements were obtained at some months and locations. We aimed to develop statistical models of the effect of oil and gas infrastructure on air concentrations. The regulatory authorities supplied the information on location of the different oil and gas facilities during the study period and, for Alberta, provided data on H2S content of wells and flaring volumes. Linear mixed effects models were used to relate observed concentrations to proximity and type of oil and gas infrastructure. Low concentrations were recorded; the monthly geometric mean was 0.1-0.2 ppb for H2S, and 0.3-1.3 ppb for SO2. Substantial variability between repeated measurements was observed. The precision of the measurement method was 0.005 ppb for both contaminants. There were seasonal trends in the concentrations, but the spatial variability was greater. This was explained, in part, by proximity to oil/gas/bitumen wells and (for SO2) gas plants. Wells within 2 km of monitoring stations had the greatest impact on measured concentrations. For H2S, 8% of between-location variability was explained by proximity to industrial sources of emissions; for SO2 this proportion was 18%. In Alberta, proximity to sour gas wells and flares was associated with elevated H2S concentrations; however, the estimate of the effect of sour gas wells in the immediate vicinity of monitoring stations was unstable. Our study was unable to control for all possible sources of the contaminants. However, the results suggest that oil and gas extraction activities contribute to air pollution in rural areas of western Canada.     

Coal-Mine Hollow Fill and Settling Pond Influences on Headwater Streams in Southern West Virginia, USA

The influences of coal-mine hollow fills and associated settling ponds in three headwater streams were assessed in southern West Virginia, USA. Fill drainage waters had elevated conductivities and metal concentrations, compared to a regional reference. Benthic macroinvertebrate richness was not affected consistently by the hollow fill drainages, relative to a regional reference, although a more tolerant community, lacking in Ephemeroptera taxa at most locations, was evident. Collector-filterer populations were elevated at monitoring stations directly below the settling ponds, indicating that the ponds’ presence influenced macroinvertebrate community structure by means of organic enrichment. Corbicula fluminea growth was enhanced in monitoring locations directly below the settling ponds, also an apparent result of organic enrichment. Results of acute water column toxicity testing with Ceriodaphnia dubia, sediment chronic toxicity testing with Daphnia magna, and in-situ ecotoxicological assessments with C. fluminea demonstrated no mortality or toxic influence at most of the sites tested below the ponds. The settling ponds appear to serve as sinks in collecting some, but not all, trace metals.     

COARSE WOODY DEBRIS AND CHANNEL MORPHOLOGY: A FLUME STUDY1

ABSTRACT: In recent years, logs and other structures have been added to streams for the purposes of altering channel morphology to improve fish habitat. This flume study was conducted to evaluate the effects of coarse woody debris on local channel morphology. Wooden dowels were used to simulate the effects of individual logs in a stream, and scour depth and surface area were determined at the end of each test run. The maximum scour depth was significantly correlated (90 percent confidence level) with both the vertical orientation of the dowels and the channel opening ratio; the scour surface area was significantly correlated (90 percent confidence level) with both the flow depth and the vertical orientation. Upstream-oriented dowels caused relatively large streambed scour and also deflected flows toward the streambank. Downstream-oriented dowels generally caused less bed scour and appeared to provide better bank protection because flow was generally deflected from the bank. In conjunction with data from field studies, these results provide information on the effects of orientation, hydraulic function, and relative stability of coarse woody debris in streams.     

TOXIC METALS IN SURFACE WATERS FROM COAL ASH1

ABSTRACT: The concentration of 10 [titanium (Ti), manganese (Mn), copper (Cu), chromium (CR), zinc (Zn), arsenic (As), selenium (Se), cobalt (Co), cadmium (Cd), and mercury (Hg)] toxic elements were measured in the water, benthic sediment, plants, invertebrates, and vertebrates of an ash basin and its drainage system at a coal-fired power plant of the Savannah River Project, Aiken, S.C., over a period of two years. During 12 months of this period the basin was essentially filled and little settling of ash occurred. In the remaining 12 months, dredging had been completed, adequate settling occurred and most of the effluent turbidity was removed. All elements were more concentrated in sediment and biota than in water, and five (Mn, Cu, As, Zn, and Se) were biomagnified by at least one biotic component as compared to concentration in benthic sediment. Plants had high accumulations of Ti, Mn, As, and Hg; invertebrates had high accumulations of Co, Hg, Cu, Cr, Cd, and As; and vertebrates greatly biomagnified Se and Zn. The streamlined biotic community of the system accomplished major removal of Mn, Zn, As, Se, and Cd from the effluent. The magnitude of bioaccumulation of Ti, Mn, Zn, As, Se, Cd, and Hg was increased during the period of adequate settling in the basin.     

Growth rate and hatching date in ostrich chicks reflect humoral but not cell-mediated immune function

A tradeoff between immune response and life history traits, in particular growth rate, has been documented in various bird species. Ostriches are fast-growing birds and a typical feature of cohorts is that offspring often differ greatly in size. We investigated the relationship between hatching date and growth rate of chicks and both cell-mediated (measured using a phytohaemagglutinin (PHA) injection) and humoral immune responses in ostrich chicks maintained on a research farm. Chicks with higher growth rates had intermediate responses to both diphtheria and tetanus toxoids. By contrast, no relation between growth rates and responses to PHA injection were found. We conclude that chick growth rate variation may be explained beyond a certain threshold by a tradeoff between the humoral response and growth. Both responses to PHA injection and humoral responses in chicks were found to decrease with chick hatching date. Within the context of ostrich farming, these results could partially explain size variations observed in cohorts of chicks, as well as high mortality rates during their first 3 months of age.