Biodegradation of mono-. di- and triethylene glycols in river waters under controlled laboratory conditions

The biodegradation of mono-, di- and triethylene glycols has been evaluated in river waters under controlled laboratory conditions. A recently developed method for the direct monitoring of these glycolsat low concentrations indicates that they degrade according to the bacterial state and temperature of the river water. Monoethylene glycol degrades completely at 20°C within 3 days; at normal winter river temperature not exceeding 8°C, monoethylene glycol is degraded partially or completely within 7 days depending on the river. Di- and triethylene glycols will be removed partially or completely within 7 days at 20°C, but for winter conditions of river flow and temperature, degradation will be minimal within this period.     

Rotavirus and reovirus stability in microorganism-free distilled and wastewaters

Survival of calf rotavirus and reovirus under controlled laboratory conditions in microorganism-free, distilled and wastewater at 8 and 26°C was examined by periodic measurement of cytopathic effects (CPE) and indirect fluorescent antibody (IFA) assays. Five samples of both water-types were collected and inoculated with the two viruses. Three samples of each type of water were divided into two bottles, one per virus, for incubation at 8°C. Two samples were used at 26°C, one per trial. In the absence of light and shaking at 26°C, 7–13 days were required for a loss of 90% infectivity for rotavirus and reovirus, while at 8°C, averages were 80 days for rotavirus and 260 days for reovirus. Virus infectivity remained for more than 30 days at 26°C and 400 days at 8°C. Rates of decline were 10–100 times greater at 26 than at 8°C, but at both temperatures, the MPN log₁₀ rate of decline of infectivity was linear.     

Influence of temperature and time of incubation on the estimation of bacterial numbers in tropical surface waters

A pour plate procedure employing 10 plates at each of 2 dilutions was used to determine the Aerobic Plate Count of bacteria in tropical surface water. The counts were conducted on 3 water samples at each of the following incubation temperatures: 20, 25, 30, 35 and 40°C. Colonies appearing on the plates were counted after 24, 48, 72, 96 and 120 h incubation. Following statistical analysis (P = 0.05) of the results it is recommended that 30°C for 72 h be adopted as a standard incubation regime for Aerobic Plate Counts of bacteria in warm tropical waters.     

Temperature and oxygen-nitrogen gas ratios affect fish survival in air-supersaturated water

Juvenile steelhead trout and juvenile chinook, coho and sockeye salmon were tested at different temperatures (8°, 9°, 10°, 12°, 15°, 18° and 20°C) at the same concentration of air-supersaturated water. Supersaturated water concentrations in different tests were 115, 116, 117, 118 and 120% saturation. Increased temperatures caused a significant (P< 0.005) increase in steelhead mortality, a significant increase (P < 0.025) in chinook deaths, but no significant effect on coho or sockeye mortality. Regression model data for steelhead indicate that a 10°C increase in temperature will decrease the time to 50% death by a factor of 2.7, e.g. from 190h at 8°C to 70h at 18°C, when tested at the same total dissolved gas pressure. Effects of different oxygen-nitrogen gas ratios on fish mortality at the same total dissolved gas pressure in supersaturated water were demonstrated with juvenile steelhead trout. Mortality was rapid (time to 50% death in 1–6 h) at 140, 135 and 130% saturation, with fish dying more rapidly as the ratio of oxygen-nitrogen decreased (decrease in O₂, increase in N₂) Mortality patterns were similar at 125%; time to 50% death occurred in 5–20 h, with more rapid deaths occurring as oxygen (O₂/N₂ ratio) was decreased.     

Experimental simulation of biodegradation in rivers: Oxygen, organic matter and biomass concentration changes

Dissolved oxygen (DO) and biochemical oxygen demand (BOD) concentration changes after an organic matter discharge into a river have been studied in the absence of oxygen transfer. According to these laboratory experiments, biodegradation of various organic compounds (glucose, glutamic acid, starch, ovalbumin and ethanol) in Seine river samples incubated at 15 30°C follow a biphasic behaviour. During a lag-phase of 10–20 h, DO decreases linearly (0.12 ppm h⁻¹ at 20°C), whereas BOD is constant. During a subsequent aerobic exponential phase, DO and BOD uptake are proportional and increase exponentially with time (0.13 h⁻¹ at 20°C). Using cell ATP as biomass indicator, the latter phase was shown to correspond to a cell division step. A kinetic model was developed for stimulating DO and BOD concentration changes after a waste water discharge at temperatures ranging between 15 and 30°C.     

Cylindrospermopsin degradation in sediments--the role of temperature, redox conditions, and dissolved organic carbon

One possible consequence of increasing water temperatures due to global warming in middle Europe is the proliferation of cylindrospermopsin-producing species from warmer regions. This may lead to more frequent and increased cylindrospermopsin (CYN) concentrations in surface waters. Hence, efficient elimination of CYN is important where contaminated surface waters are used as a resource for drinking water production via sediment passage. Sediments are often characterized by a lack of oxygen and low temperature (i.e. approx. 10 °C). The presence of dissolved organic carbon (DOC) is not only known to enhance but also to retard contaminant degradation by influencing the extent of lag phases. So far CYN degradation has only been investigated under oxic conditions and at room temperature. Therefore, the aim of our experiments was to understand CYN degradation, focusing on the effects of i) anoxic conditions, ii) low temperature (i.e. 10 °C) in comparison to room temperature (23 ± 4 °C) and iii) DOC on lag phases. We used two natural sandy sediments (virgin and preconditioned) and surface water to conduct closed-loop column experiments. Anoxic conditions either inhibited CYN degradation completely or retarded CYN breakdown in comparison to oxic conditions (T_1/2 (oxic) = 2.4 days, T_1/2 (anoxic) = 23.6 days). A decrease in temperature from 20 °C to 10 °C slowed down degradation rates by a factor of 10. The presence of DOC shortened lag phases in virgin sediments at room temperature but induced a lag phase in preconditioned sediments at 10 °C, indicating potential substrate competition. These results show that information on physico-chemical conditions in sediments is crucial to assess the risk of CYN breakthrough.     

The effect of temperature on the removal of non-ionic surfactants during small-scale activated-sludge sewage treatment—I. Comparison of alcohol ethoxylates with a branched-chain alkyl phenol ethoxylate

The degree of biodegradability of three non-ionic surfactants has been assessed using small-scale activated-sludge sewage treatment plants. The effect of temperature on biodegradability was studied by operation at 15°, 11° and 8°C.The two alcohol ethoxylate surfactants tested were well degraded at all three operating temperatures. The alkyl phenol ethoxylate surfactant tested was well degraded at 15°C but at lower temperatures the biodegradability was dependent on concentration. At 5 mg 1⁻¹, greater than 90 per cent removal was achieved but at 20 mg 1⁻¹ the degree of removal fluctuated between 40 and 95 per cent at 11°C and between 20 and 80 per cent at 8°C.The present results have been compared with those obtained using the same surfactants in community trials at a small sewage works employing biological filtration. Although a similar temperature effect was observed with the alkyl phenol ethoxylate, the biodegradabilities obtained in the laboratory were consistently greater than those obtained at the sewage works, perhaps because of the constant conditions of the laboratory test.     

The effects of power plant passage on zooplankton mortalities: Eight years of study at the Donald C. Cook nuclear plant

Zooplankton mortalities resulting from passage through the Donald C. Cook Nuclear Plant (southeastern Lake Michigan) were studied over an 8-year (1975–1982) period. The power plant operated at a low ΔT (< 12°C) and discharge water temperatures did not exceed 35°C (except September 1978). While zooplankton mortalities were significantly greater in discharge than intake waters, differences were small, averaging < 3%. There was no evidence of additional delayed effects on zooplankton mortality following plant passage. Calanoid copepods (Diaptomus spp, Eurytemora affinis and Limnocalanus macrurus) were most sensitive to plant passage, cyclopoid copepods least sensitive, while cladocerans (Daphnia spp, Eubosmina coregoni) were intermediate in sensitivity. There was no relationship between zooplankton mortalities and temperature (ΔT, discharge water temperature), suggesting that thermal stresses were not the major source of mortality. The single exception was September 1978 when discharge water temperatures exceeded 35°C and there were large differences between intake and discharge water zooplankton mortalities (net mortality differences of 14–22% for the two units). Mechanical stresses appeared to be the major cause of zooplankton mortality. However, there was only a weak relationship between mortality as a result of plant passage and zooplankton size. Based on our long-term preoperational (1970–1974) and operational (1975–1982) ecological studies in the vicinity of the power plant, we hypothesize that fish predation, rather than power plant operation, probably was the major source of zooplankton mortality in inshore waters during much of the year.     

Thermal tolerance of zooplankton

First immature instar Daphnia pulex Leydig acclimated at 5, 10, 15, 20, 25 and 30°C, and Daphnia magna Straus acclimated at 10, 15, 20, 25 and 30°C, were instantaneously immersed at the specified temperatures which differed from acclimation temperatures by 10°C or more. Observations for mortality were made at regular intervals for 48 h or longer until at least one molting had occurred. Organisms acclimated at the same temperatures were also instantaneously immersed at 35°C, an ultimately lethal temperature, and followed to 95% mortality. Daphnia pulex acclimated at 20°C were stepped over varying rates of temperature change to 35°C and observed for mortality over a 48-h period. Thirty first immature instar organisms were used in each test, and tests were carried out in temperature controlled water baths and incubators. Filtered pond water was used for culture and testing.Both species survived instantaneous temperature changes over the entire normal tolerance ranges tested. Animals succumbed more rapidly upon instantaneous immersion at 35°C as the temperature at which they were acclimated decreased, with D. magna succumbing more rapidly than D. pulex from all acclimation temperatures. Daphnia pulex acclimated at 20°C and stepped to 35°C at varying rates of temperature change exhibited a decreasing 48-h mortality percentage as rates decreased from 6°C h⁻¹ to 1.33°C h⁻¹.Shortcomings in methodologies of previous thermal tolerance studies on zooplankton were discussed, and recommendations were made as to how these methods can be improved.     

Dissolved air flotation in hot water

The effects of increased water temperature on dissolved air flotation have been measured. At temperatures up to 80°C the efficiency of air dissolution by spraying water over proprietory packing, bubble size distributions and the air-solids ratios required for iron floc flotation were found to be close to the values commonly found for those obtained at ambient temperature. Bubble rise rates at 80°C were three times faster than at 20°C and the onset of severe bubble coalescence at 80°C occurred at air dissolution pressures above 350 kPa.     

Influence de sediments argileux incorpores au milieu d'insemination sur le succes de la fecondation chez la truite arc-en-ciel (Salmo Gairdneri)

The aim of this paper is to determine whether clay sediments suspended in water can prevent trout eggs from being fertilized. Kaolinite-rich clays (granulometric fraction: <2μm) (Fig. 1) were suspended in an artificial insemination diluent in doses ranging between 0 and 20 g l⁻¹. The eggs were exposed for 1, 10 or 20 min (experiment A) or inseminated (experiment B) in the diluent-sediment mixture. In experiment (C), the eggs were exposed to this mixture at three different temperatures (10, 15, 20°C). After insemination, the eggs were incubated for 10 days at 10°C and the percentage of eyed-eggs was used as an approximation of the fertility rate. The presence of clay sediments in the medium in which artificial insemination was carried out did not affect fertilization rate after the ovules had been exposed during 1 min to clay suspensions, at any of the temperatures used (8°C: Fig. 3; 10–15 or 20°C: Fig. 5) or at any of the sperm dilution rates (10⁻², 10⁻³, 10⁻⁴) (Fig. 3). On the contrary, there was a significant decline (P < 0.01) in the fertilization rate after the eggs had been exposed for 10 min at 8°C to doses of sediment exceeding 1.2 g l⁻¹ (Fig. 2). The fertilization rate also decreased significantly (P < 0.05) when the dose of sediment in the medium increased after 20 min at 20°C and 40 min at 15°C (Fig. 4). The 15 and 20°C temperatures were unfavourable for the eggs anyway. It is probable that fertility decreased due to micropyle clogging when the eggs were exposed longer than 10 min to the sediments. It is concluded that presence of sediments in the medium in which the gametes meet does not prevent fertilization.     

The stability of bovine parvovirus and its possible use as an indicator for the persistence of enteric viruses

Bovine parvovirus 1 (Haden virus) gives with grown in 0–24 h secondary cultures of calf kidney a pronounced CPE. The virus is very thermoresistant, it takes e.g. at 60°C 6 h to decrease the titer of infectivity 1 log unit.When seeded in liquid manure the virus becomes inactivated at a rate of around 6–8 days for 1 log unit under aerobic conditions at 5–20°C. The inactivation under anaerobic conditions is very temperature dependent: at 5°C it takes about 200 days to decrease the titer 1 log unit, but at 20°C a rate of inactivation of 20 days per log unit of virus was found.It is suggested that the bovine parvoviruses may be useful as indicators in connection with evaluations of the importance of viral bovine faecal pollution. For evaluations of treatment efficiencies it is suggested that these parvoviruses may also be used as indicators for human enteric viruses like the virus of infectious hepatitis.     

Development of a high-temperature-resistant mortar by using slag and pumice

The effects of high temperatures up to 900 °C on the mechanical properties and the microstructure of cement-based pumice mortars incorporating different amounts of ground granulated blast furnace slag (GGBFS) were investigated in this study. The residual compressive and flexural strength of mortar specimens were determined after exposure to high temperatures. The results have indicated that the effect of GGBFS incorporation on high-temperature resistance of pumice mortar is shown significantly at 900 °C. At this temperature level, the mortar containing 80% GGBFS exhibited only 23% and 28% compressive strength loss when cooled in air and water, respectively, where as mortars without GGBFS lost almost 70% of their strength. Furthermore, none of the GGBFS incorporated mortar specimens showed compressive strength loss up to 600 °C when cooled in air. The most severe conditions in terms of strength loss due to high temperatures were flexural loading and water cooling case.     

A comparison of thermal loading effects on bacterial populations in polluted and non-polluted aquatic systems

Water from two aquatic systems including a new, non-polluted lake, and a lake receiving municipal and industrial wastes was studied for alterations in bacterial populations following temperature increases of 5–10°C above ambient. Lake water was studied under laboratory conditions utilizing 50 1. tank batteries to permit controlled temperature maintenance.Plate count agar was used for counts of total culturable heterotroph and chromagenic colonies. Selected limiting nutritional media were used to determine these types. Increases in total counts were observed in all systems during initial periods at temperatures 3–5°C above ambient; however, at 5–10°C above ambient. total counts and the number of different genera isolated were reduced. Effects on nutritional types and percentage of chromagenic types present were analyzed.     

The effect of acclimation temperature on the interactions of chlorine, ΔT and exposure duration to eggs, prolarvae and larvae of striped bass, Morone saxatilis

The effect of five acclimation temperatures on the interactions of total residual chlorine (TRC) (0.00, 0.15 and 0.30 mg l⁻¹, ΔT (2, 6, 10°C above acclimation temperature) and exposure duration (0.08, 2.0, 4.0 h) conditions were evaluated for striped bass, Morone saxatilis, eggs, prolarvae and larvae. The range of acclimation temperatures (12.5, 15.0, 17.5, 20.0, 22.5°C for eggs and prolarvae; 15.0, 17.5, 20.0, 22.5 and 25.0°C for larvae) tested with each life stage included the lower, optimum and upper environmental temperatures that exist when these life stages may be subjected to power plant chlorination conditions. All organisms were tested using a fractional composite design in a 3 × 3 × 3 factorial matrix. Mortality of the eggs was highest at temperatures below 17.5°C; overall mortality decreased with increasing acclimation temperature. The factor causing the greatest effect with this developmental stage was ΔT, followed by TRC and exposure time. Mortality of striped bass prolarvae increased with acclimation temperature after exposure to interacting treatment factors. Interactions involving TRC were most important from 12.5 to 17.5°C; ΔT interactions were prominent at acclimation temperatures of 20.0 and 22.5°C. Larvae mortality was highest at 20°C with a gradual decrease at 25.0°C. Interactions involving ΔT, TRC and exposure time all contributed to the mortality of this life stage; TRC and ΔT caused the main effects. Striped bass eggs were the most resistant life stage; mean mortality averaged over all acclimation temperatures was approximately the same for prolarvae and larvae.     

Water quality criteria for European freshwater fish: Report on ammonia and inland fisheries

In establishing water quality criteria for European inland fisheries, the effect of ammonia is an important factor to be considered. Sewage effluent, effluents from certain industries and from agriculture are common sources of ammonia in water.The harmful effects of ammonia on fish are related to the pH value and the temperature of the water due to the fact that only the un-ionized fraction of ammonia is poisonous. The un-ionized fraction increases with rising pH value, and with rising temperature.Fish differ slightly in their tolerance to ammonia depending on species. The difference in tolerance being more significant for short periods of exposure. The difference in tolerance is, however, not great enough to justify different criteria for different species.The lowest toxic concentration found for salmonids is 0·2 mg NH₃ 1⁻¹ (un-ionized), but other adverse effects caused by prolonged exposure are only absent at concentrations lower than 0·025 mg NH₃ 1⁻¹ (un-ionized). Concentrations of total ammonia which contain this amount of un-ionized ammonia vary from 19·6 mg 1⁻¹ (pH 7·0, 5°C) to 0·12 mg 1⁻¹ (pH 8·5, 30°C).The criterion should not be applied to temperatures below 5°C or to pH values above 8·5 when other factors have to be taken into consideration.     

Prediction of the temperature dependence of electrical conductance for river waters

The application of mixed electrolyte theories to the prediction of the electrical conductivity of 14 river-water samples covering a range of ionic strength and temperatures between 5 and 25°C has been evaluated using a new program, CONCAL. Both the Fuoss-Onsager, FO, and Lee-Wheaton, LW, theories produce better agreement between the measured and predicted conductivities for the majority of the samples than the simple product equation. For river waters with a charge imbalance of less than 10%, the prediction of the simple product, FO and LW equations are on average within 11.1, 3.4 and 3.7%, respectively, of the experimental values over the range of temperatures considered. The major error in the predictions of the FO and LW models is associated with the reliability of the chemical analytical data input to CONCAL. The accuracy of the predictions of the models is also discussed in terms of the magnitude and sign of the charge imbalance calculated for each of the samples from the analytical data.Five equations that are available to apply a temperature compensation to conductivity data to predict values at 25°C have been tested over a temperature range of 5–25°C. The best performance is achieved using the modified Walden's product.The relationship between the measured conductivity at 25°C, κ(25), and ionic strength, I, has been calculated to be I = 0.0021 + 0.0148 κ(25) with I in mmol dm⁻³. This observation is discussed by reference to the predicted relationship for simple binary mixtures of NaCl and Ca(HCO₃)₂.     

Biodegradation of synthetic crude oil in two rivers of Northern Alberta, Canada

Samples of water and epilithon from two brown-water rivers in Northern Alberta, one of which has cut its way through the Athabasca oil sand deposits, were all able to biodegrade the saturate fraction of synthetic crude oil, a light refined oil resulting from the up-grading of oil sand. This would suggest that the oil degradative capability of river microorganisms was ubiquitous in this area.Higher degradation rates were observed at 20°C than at 4°C, but even at this low temperature, degradation was quite rapid, a noteworthy point, since these rivers are normally close to 0°C for 6 months of the year.     

Influence of temperature on lake bacterial activity

Oxygen utilization rates of isolates of Flavobacterium from Lake Ontario and Lake Superior, and an E. coli from the St. Lawrence River were observed at 4 and 20°C. Data presented indicate that the oxygen utilization rate of the lake bacteria at 4°C is similar to that of the river bacteria at 20°C. The observation is also extended to explain the seemingly satisfactory biodegradation of nutrients discharged into water bodies in temperate climates.     

Comparative study on organic constituents in polluted and unpolluted inland aquatic environments—II: Features of fatty acids for polluted and unpolluted waters

Fatty acids were analyzed for polluted river waters from the Tokyo area and unpolluted river, brook, reservoir and pond waters from the Ogasawara (Bonin) Islands to elucidate their features for polluted and unpolluted waters. Fatty acids ranging from the carbon chain length of C₈-C₃₄ including unsaturated and branched acids were found with the great predominance of even-carbon numbers and lower molecular weight ranges (C₁₃–C₁₉) in the water samples from the Tokyo area and Ogasawara Islands. It was thus confirmed that no marked changes in fatty acid composition between polluted and unpolluted waters are absent. However, the total contents of the acids (average, 270 ± 120 μg 1⁻¹ at 90% confidence limits) as well as the FAC (fatty acids as carbon)/TOC (total organic carbon, 2.6 ± 0.93%) and FAC/EOC (extractable organic carbon with ethyl acetate, 16 ± 6.7%) of river water samples from the Tokyo area were considerably higher than those of the waters from the Ogasawara Islands (58 ± 29 μg 1⁻¹, 0.79 ± 0.48% and 2.1 ± 0.51%, respectively). These higher values for the Tokyo area should be due to sewage.A filtering method showed that most of fatty acids (>95%) was present in particulate fractions. In addition, the content of free fatty acids was fairly lower than that of combined fatty acids. Further, unsaturated fatty acids were detected only in combined forms both in particulate and dissolved fractions. They are considered to be present as esters in polluted and unpolluted waters.