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.     

Boston harbor outfall tunnel: An environmental imperative

In February 1989, the Massachusetts Water Resource Authority (MWRA) began the design and construction of a 15.3-km subsea tunnel and ocean riser system to discharge effluent in conjunction with the design and construction of a large secondary treatment plant. The court-mandated schedule required the tunnel and risers to be completed in July 1995. The paper discusses the project from the viewpoints of management, concept design and construction methods, including the ocean riser system. Key to th success of the project is the accuracy of the location of the risers. The design calls for a final tunnel alignment to be driven within 10 m of the riser shafts, beginning at a distance of 13.1 km from shore.     

Geomechanical model simulation for the varied rock formations of the Kadana dam foundation,Gujarat, India

Bulletin of Engineering Geology and the Environment - Precambrian layered rocks consisting of quartzites, phyllites and metagreywackes of the Aravallis having a large variation in thickness,...     

Book reviews

The Annals of Regional Science -     

A large-scalein situ permeability test at Presenzano (Italy)

Bulletin of Engineering Geology and the Environment - Soil permeability had to be carefully determined in order to decide whether or not the whole lower reservior (750.000 m2) of the Presenzano...     

Antimicrobial multiresistance in bacteria isolated from freshwater Chilean salmon farms

The intensive use of antimicrobial agents, mainly oxytetracycline, to prevent and control bacterial pathologies in Chilean salmon culture is a frequent practice. A total of 103 gram-negative oxytetracycline-resistant bacteria recovered from various sources of 4 Chilean freshwater salmon farms were identified and investigated for their susceptibility patterns to various antibacterial agents, by using an agar disk diffusion method. Antibacterial resistance patterns of isolates were not correlated with bacterial species or strain source. A high number of bacteria resistant to amoxicillin, ampicillin. erythromycin, and furazolidone, as well as an important frequency of bacterial resistance to florfenicol, chloramphenicol, cefotaxime and trimethoprim-sulfamethoxazole was found. On the contrary, the proportion of bacteria resistant to gentamicin, kanamycin, flumequine and enrofloxacin was rather low. Resistant microflora showed a high taxonomic variability and mainly consisted of non-fermenting bacteria (77.7%). These strains mainly belonged to the species Pseudomonas fluorescens (29), Aeromonas hydrophila (10), Stenotrophomonas maltophilia (6), isolated from salmon fingerlings, and Acinetobacter lwoffii (5) isolated from pelletized feed. The occurrence of simultaneous resistance to various antibacterials was frequent. We observe a high frequency of bacteria resistant to 6-10 antibacterials (74 strains), and antibiotic resistance index (ARI) values ranging from 0.38 to 0.48 for the four salmon farms studied. These results suggest that Chilean salmon farms might play a role as reservoirs of antibacterial multiresistant bacteria, thus prompting the necessity for a more restrictive attitude towards the intensive use of antibacterials in salmon farming.     

A semiautomated procedure for the determination of phosphorus in water, waste waters and particulates

Improved procedures for the determination of total dissolved phosphorus (TDP), particulate phosphorus (PP) and dissolved inorganic orthophosphate (DP) are described. Organic particulate material is solubilized in 5 n NaOH, and phosphorus compounds are oxidized and mineralized to orthophosphate by persulfate digestion. DP is determined by an improved automated molybdenum blue procedure that does not require sample pH adjustment or a correction for silicate interference in the 0–50 mg Si 1^?1 range. The use of 36-position digestion racks allows 32 TDP or PP samples to be digested in ca. 1 and 4 h respectively. Detection limits in μg of phosphorus 1^?1 are DP, 2; TDP, 5; and PP. 1. Waste water samples were analyzed for TDP and PP by the nitric acid-sulfuric acid procedure and by the proposed method. There was no significant difference between the two sets of data (P > 0.45).     

Interaction effects of multiple pool fires

What are the effects of flame behavior of a number of fires burning in close proximity to one another? The results of measurements of burning rates, heat feedback, flame height, and flame trailing are reported for fires involving liquid pools.     

Studies on oxidation of benzo [a] pyrene by sunlight and ozone

The destruction of the carcinogen benzo[a]pyrene (BaP) by light is well known; laboratory workers are routinely advised to cover fluorescent lamps with yellow filters while treating samples containing BaP. However until recently the mechanism of oxidation by sunlight and ozone had not been studied in detail. Concentrations of benzo[a]pyrene in urban air are in the range of 5–10 μg/1000 m³. Oxidant concentrations (predominantly in the form of ozone) are reported to be in the range of 0.01 ppm (22 μg per m³). Thus a sampling system with a filter paper would filter about 22,000 μg of ozone passing through and collect about 5 μg of BaP for analysis. The effect of interactions of such large ozone concentrations with BaP deposited on the filter paper is reported; data for the oxidation rates for benzo[a]pyrene coated on quartz surface and exposed to ozone or sunlight are presented. The oxidation products were analysed by thin-layer chromatography and highpressure liquid chromatography. From about eight products detected in these experiments, three have been identified as quinones based on UV-absorption spectrometry and mass spectrometry. Oxidation rates as high as 100% per hour of exposure are observed when less than 0.1 μg of BaP is coated inside the quartz tubes and exposed to ozone or sunlight. Oxidation rates for benzo[a]pyrene (using tritiated BaP) were determined for two types of experimental conditions. In the first set, tritiated BaP was spotted onto a glass fibre paper and sampling continued for 24 h; the loss of BaP was found to be 88%. In the second set tritiated BaP was spotted at intervals of one hour, for eight hours, while sampling is being carried out and the loss of BaP during the period was estimated to be 50%.