Observations on the changes in nitrate concentrations along streams in seven upland moorland catchments in Northeast Scotland

River water has been sampled under baseflow conditions in both summer and winter at c. 250-m intervals along the length of each of seven rivers in northeast Scotland, and the nitrate contents have been determined. The resultant data have been examined in the context of the nitrogen saturation hypothesis. Capacity of the catchment soils to retain nitrate was generally minimal in winter. Although biological uptake of nitrate was evident in summer, in the upper part of each catchment substantial nitrate leaching still occurred. The phenomenon was most marked in water draining from hill peats, except where these were conspicuously waterlogged. The results are discussed in the context of possible nitrogen saturation effects on upper catchment slopes.     

Oxygen consumption and activity of the white sucker (Catostomus commersoni), in lethal and nonlethal levels of the organochlorine insecticide, methoxychlor

The survival, oxygen consumption and spontaneous activity of suckers were determined at 15°C in water containing different concentrations of methoxychlor in ethanol, ethanol, and no added substances. A dynamic bioassay was used to estimate the 96 h LC50, which was found to be 0·0345 ppm. Routine oxygen consumption was determined in a continuous-flow respirometer, and the activity was recorded in separate experiments by measuring the water disturbance using silver wire electrodes.After 24 h fish exposed to untreated, ethanol-treated and 0.01 ppm methoxychlor-treated water had oxygen uptake rates which were relatively constant and near standard levels. At 0.10 ppm methoxychlor (lethal to all fish within 85 h), oxygen consumption rates were 2–3.5 × as high as those of control fish. Activity also greatly increased. The fish lost their balance along with the coordination between opercular and locomotor movements. Suckers that died in 0.04 ppm methoxychlor showed oxygen uptake rates and poisoning symptoms similar to 0.10 ppm treated fish, while those that survived this treatment had rates similar to control fish. The increase in ventilation which accompanies this hyperactivity may result in increased uptake of insecticide and thereby explain the irreversible nature of the response.     

Planning and designing for the multiple use role of habitats in urban/suburban landscapes in the Great Basin

Most researchers agree that preserving, creating, and restoring urban wildlife habitats has to be an interdisciplinary undertaking if it is to succeed. Ecologists and wildlife biologists must be key participants. The culturally modified context of most urban habitats suggests that landscape architects also have a primary role to play.Open space in the urban/suburban environment is a scarce and valuable resource. Private and public sector pressure to convert these spaces to commercial or intensive recreational uses are immediate and intense. Presenting arguments to preserve or restore urban open space solely as habitat for wildlife is seldom successful. Decision makers are more likely to support urban wildlife habitat programs if other uses are also accommodated.There is a growing body of research data that suggests that wildlife are being adversely impacted by multiple uses of urban habitats. The challenge for planners and designers is to minimize adverse impacts and capitalize on those attributes of other uses that enhance habitat value. Planning for the temporal as well as spatial dimensions of site uses is required if the needs of wildlife are to be met.The paper presents three general areas in which landscape architects have traditionally contributed to an interdisciplinary approach to urban wildlife habitat planning: contextual perspective, problem solving process, and design/technical execution.Reflecting back on his past 10 years of experience as a landscape architect planning urban wildlife habitats, the author presents several case study projects in which: (A) accommodation of multiple use objectives, including wildlife habitat, was required; (B) interdisciplinary teams participated in the planning and design process; (C) key principles from the fields of landscape ecology, conservation biology and wildlife biology were applied to facility and activity location, habitat configuration, and management.Plans of completed projects are used to illustrate how habitat values were preserved or enhanced and multiple uses accommodated in public open spaces. The paper concludes with a brief summary of keys to success common to each project.     

Oxygen transfer in a rotating disc treatment plant

In this paper experiments are described in a bio-disc pilot plant. A new method has been developed for a reproducible measurement of the thickness of the waterfilm on the rotating discs. The results were used to calculate the oxygen transfer coefficient into water (K_L). The values of K_L, calculated in this way, appeared to be considerably higher than experimental K_L-values, which is mainly due to the fact that the water layer on the rotating disc is outdistanced by the disc. This effect has not been taken into account in the literature so far.     

Toxicity bioassay of heavy metals in water using Tetrahymena pyriformis

The toxicities of five heavy metal compounds on the survival of the ciliated protozoan Tetrahymena pyriformis were determined. Three-day old cultured cells were exposed to five concentrations of each test compound in one or more of three water series; distilled, soft, and hard water. A culture of each sample was placed in a plastic petri dish and covered with mineral oil to prevent evaporation. The cells were counted initially, then again at 0·5 h, 1 h, 2 h, 1 day, 2 days, 3 days, and on the fourth day. Lethal threshold concentrations and tolerance limit medians were determined by graphic methods. On a weight bases cadmium was most toxic, followed in decreasing toxicity by mercury, cobalt, zinc, and lead. Compared to similar fish data, all heavy metals were more toxic to T. pyriformis except lead. The toxicity of lead in soft versus hard water exemplified an antagonistic effect with greater than seven times the amount of lead necessary in hard water to produce comparable mortality as lead in soft water. On the other hand, the toxicity of mercury is about twice as great in hard water as in soft water (a synergistic effect). T. pyriformis appears to be a more sensitive indicator than fish of heavy metal contamination of water. T. pyriformis bioassay should prove a good means of determining the existence of many water pollutants.     

The uptake of heavy metals by epiphytic bacteria on Alisma plantago-aquatica

Bacterial epiphytes on the surface of the fresh-water plant Alisma plantago-aquatica collected from a polluted river were found to be a major factor in contributing to the total metal concentrations of the plant. The removal of epiphytes from the leaf surface resulted in significant reductions in the concentrations of Cr (reduced by 15–50%), Cu (30–35%), Fe, Pb, and Zn (10–50%). While numbers of epiphytes and concentrations of heavy metals increased in samples collected from polluted water compared with from unpolluted water, the fraction of metals held by the epiphytes appeared to remain similar for all samples.     

Classic and novel brominated flame retardants (BFRs) in common sole (Solea solea L.) from main nursery zones along the French coasts

Brominated flame retardants (BFRs) were investigated in juvenile common sole from nursery zones situated along the French coast in 2007, 2008 and 2009. Extensive identification was performed with regard to PBDEs, novel BFRs 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenylethane (DBDPE), and other non-PBDE BFRs, namely, hexabromobenzene (HBB) and 2,2′,4,4′,5,5′-hexabromobiphenyl (BB-153). Polybrominated diphenyl ether (PBDE) concentrations (Σ 14 congeners) ranged from 0.01 ng/g to 0.16 ng/g wet weight (ww) in muscle, and 0.07 ng/g to 2.8 ng/g ww in liver. Concentrations were in the lower range of those reported in the literature in other European locations. Lower PBDE concentrations, condition indices and lipid contents were observed in the Seine estuary in 2009, possibly in relation to a lower water flow. The PBDE patterns and ratios we observed suggested that juvenile sole have a relative high metabolic degradation capacity. Non-PBDE BFRs were detected at lower levels than PBDEs, i.e., within the < method detection limit - 0.005 ng/g ww range in muscle, and < method detection limit - 0.2 ng/g ww range in liver. The data obtained is of particular interest for the future monitoring of these compounds in the environment.     

A Microcomputer Model for Flood Prediction with Applications

Abstract: A generally applicable mathematical model, tailored for use on a Personal Computer, as the design tool to simulate unsteady flood flow in a network of interconnected rivers has been developed and applied to the Sham Chun River along the border between Hong Kong and the People's Republic of China. The effect on the improved Sham Chun River due to the proposed river training in the River Indus, one of its tributaries, is evaluated. The one-dimensional unsteady flow model itself is broadly applicable to a wide range of hydrologic conditions and varying field situations. It incorporates real hydraulic features including branched channels and 'tidal flats' flooding and drying. The time history of water stages and discharges are computed at any desired location throughout the connected essentially one-dimensional channel network subject to initial and boundary conditions. Details are given of techniques adapted in using the computational scheme to quantify the unsteady flow condition and the means to assure an efficient numerical solution as well as to verify the accuracy of the computed outputs by subjection to carefully selected schematic simplified test cases and real prototype cases with numerical solution method is a useful predictive engineering tool in river design.     

Levels of copper in the urine of women from nonpolluted farming regions of Japan.

Nearly 1500 spot urine samples were collected in the winter of 1987-1988 from women of seven farming prefectures located throughout Japan. Samples were analyzed for copper by flameless atomic absorption spectrometry. The copper content of the urine samples (Cu-U) distributed log-normally with a geometric mean (geometric standard deviation) of 36.9 (1.47) micrograms/l after adjustment for the specific gravity of urine of 1.016. The 95% confidence range was 17.1-79.7 micrograms/l. Neither alcohol consumption nor smoking habit affected the Cu-U. A literature survey showed that the observed level appears to be somewhat higher than previously reported values.