Acute toxicity and behavioral responses of coho salmon (Oncorhynchus kisutch) and shiner perch (Cymatogaster aggregata) to chlorine in heated sea-water

The acute toxicity and behavioral response to chlorinated and heated sea-water was determined for coho salmon smolts and 1–3 month old shiner perch. LC₅₀'s were determined for 7.5, 15, 30 and 60 min exposure times; 13, 16 and 20°C (Δt = 0, 3, 7°C) temperatures and total residual oxidant (TRO) concentrations ranging from 0.077 to 1.035 mg l⁻¹. The mean 60 min LC₅₀ for shiner perch was significantly reduced (P ≤ 0.05) from 308 μg l⁻¹ TRO at 13°C to 230 μg l⁻¹ TRO at 20°C. The 60 min LC₅₀ for coho salmon decreased from 208 μg l⁻¹ TRO at 13°C to 130 μg l⁻¹ at 20°C. The LC₅₀'s for coho salmon in chlorinated sea-water averaged 55% of those for shiner perch. The relationship between TRO concentration, exposure time, and percent survival in chlorinated sea-water at 13°C is presented for both species.A significant (P ≤ 0.01) avoidance threshold for coho salmon occurred at 2 μg l⁻¹ TRO and was reinforced with increasing temperature. A significant (P ≤ 0.01) avoidance threshold for shiner perch occurred at 175 μg l⁻¹ TRO, while a significant preference (P ≤ 0.05 or 0.01) response at 16°C and 20°C occurred at 10, 25, 50 and 100 μg l⁻¹ TRO. The ecological implications of the toxicity tests and the behavioral responses are discussed.     

The effects of phenol and some alkyl phenolics on batch anaerobic methanogenesis

Phenol and seven alkylphenols (o-, m- and p-cresol, 2.5-, 2.6-, 3.4- and 3,5-dimethylphenol) were added at various concentrations to aliquots of domestic anaerobic sludge in Hungate serum bottles and these were incubated at 37°C. The concentration of methane in the headspace gas was monitored to determine if the phenolics were fermented to methane or if they inhibited the anaerobic process. Only phenol and p-cresol were fermented to methane. At 500 mg l⁻¹ (but not at 300 mg l⁻¹) 2,5-, 3,4- and 3,5-dimethylphenol reduced the rate and the amount of methane produced. The cresols were inhibitory at 1000 mg l⁻¹ but not at 400 mg l⁻¹.In cultures supplemented with acetate and propionate (VOA), and in unsupplemented cultures, phenol at concentrations up to 500 mg l⁻¹ was fermented to methane. Between 800 and 1200 mg l⁻¹ phenol, methane production was neither enhanced nor inhibited relative to control cultures containing no phenol. Inhibition of methane production was evident when phenol was present at 2000 mg l⁻¹. Thus the methanogens are less susceptible to phenol inhibition than are the phenol-degrading acid formers. In similar experiments with p-cresol: enhanced methane production was observed at concentrations of 400 mg l⁻¹; no enhancement or inhibition was observed at 600 mg l⁻¹; and inhibition was noted when p-cresol was present at 1000 mg l⁻¹.     

Cadmium uptake by freshwater bacterial communities

Microcosm experiments in chemostat incubated at 20°C showed that cadmium contamination does not greatly affect bacterial communities in cultures contaminated with up to 1 mg Cd l⁻¹.Bacterial productivity remains unchanged and cadmium-resistant strains arise quickly and in great number. The cadmium accumulation by bacteria depends on the bacterial productivity. The free bacteria can accumulate up to 1200 ppm cadmium whereas the adhering bacteria concentrate up to 6100 ppm. At a steady state, 11–29% cadmium is removed from the water phase of cultures.     

Detoxification of seawater used for gas scrubbing in the steel industry

Cyanide ion present in seawater after scrubbing blast furnace and coke ovens gases can be removed by sedimentation of hexacyanoferrate complexes followed by oxidation of residual cyanide with Caro's acid. Zinc ion is removed at the same time by adsorption on the hexacyanoferrate/hydrous ferric oxide precipitate.Sulphide is precipitated as ferrous sulphide, then oxidised by atmospheric oxygen. At 25°C and using an Fe/CN ratio of 1·00, initial concentrations of 50 mg l⁻¹ of CN⁻ and 10 mg l⁻¹ of Zn²⁺ in seawater are reduced to 5–7 mg l⁻¹ and 0·1 mg l⁻¹. Subsequent treatment with H₂SO₅/CN = 1·2 reduces the [CN⁻] to 0·1 mg l⁻¹.Treatment of a combined blast furnace/coke ovens effluent ([CN⁻] = 24 mgl⁻¹, [Zn²⁺] = 4·0 mgl⁻¹) with Fe/CN = 1·5 reduced [CN⁻] to 0·2 mg l⁻¹ and [Zn²⁺] to <0·1 mgl⁻¹. Subsequent treatment with H₂SO₅/CN = 2·0 reduced [CN⁻] to 0·2 mg l⁻¹. The process operates best in the pH range 7–9 and so is not affected by the buffer characteristics of seawater.     

Enhanced uptake of phosphorus by activated sludge-effect of substrate addition

Studies were undertaken to examine the effect of substrate addition upon the release and subsequent uptake of phosphorous by a biological wastewater treatment laboratory scale system.A train of six reactors were fed at a rate of 16 ml min⁻¹ raw wastewater using a sludge recycle ratio of 0.75 (12 ml min⁻¹). The first two reactors were simply stirred (anoxic) without the addition of air and the remaining four were aerated with excess air.Various substrates were added to the first reactor (anoxic) at different concentrations. It was determined that all the short chain substrates tested enhanced the release of phosphorus in the anoxic stages and subsequently led to increased biological uptake (removal) of phosphorus. The substrates tested included sodium acetate, acetic acid, butyric acid, ethanol and methanol.It was determined that 30 mg l⁻¹ sodium acetate was the optimum dose for biological release and uptake of phosphorus and the addition of any greater concentration had marginal effect on the ultimate removal of phosphorus.The effect of these substrates showed some specificity regarding phosphorus release, with butyric acid causing the greatest release and sodium acetate the least. However as far as phosphorus uptake (removal) was concerned, this phenomenon of substrate-specificity was less significant. For all substrates, effluent phosphorus concentration was within ± 1 mg l⁻¹ with an approximate mean concentration of 1 mg l⁻¹ residual.Phosphorus released (approx. 14 mg l⁻¹) at higher temperature (29°C) was 75% greater than at the lower temperature (24°C). Similarly the final residual phosphorus at 29°C was 33% lower than at 24°C.     

An improved determination of chemical oxygen demand in water and wastes by a simplified acid dichromate digestion

A simplified and improved chemical oxygen demand (COD) procedure is suitable for water and waste water samples containing up to 1500 mg Cl l⁻¹. Samples are digested with sulfuric acid, potassium dichromate, silver sulfate, mercury(II) sulfate and sulfamic acid in open glass tubes for 2 h at 140 ± 2°C without boiling, and excess dichromate is determined colorimetrically at 440 nm. The use of 49-position digestion racks, a large oven and a spectrophotometer fitted with a 1-cm flow cell allow analysis of ca. 12 samples h⁻¹. A correction for chloride interference is not required in the 0–500 mg Cl l⁻¹ range. The detection limit is 3 mg l⁻¹, and the relative standard deviation at the 112 mg COD l⁻¹ level is 4.3%. Thirty-five waste water samples were analyzed by the standard dichromate reflux method and by the proposed procedure. There was no significant difference between the two sets of data (P > 0.25). Recovery data for 15 major water pollutants including benzene, toluene and pyridine are presented.     

The relationship between dissimilatory nitrate reduction and oxygen uptake by cells of an Alcaligenes strain in flocs and in suspension and by activated sludge flocs

The oxygen uptake and the dissimilatory nitrate reduction by anaerobically grown cells of a denitrifying Alcaligenes strain, occurring in floc form or in suspension, were studied at different oxygen concentrations in the surrounding medium. When the oxygen concentration in the medium fell below 1·5 mg l⁻¹, the nitrate reduction by the cells within flocs increased considerably. The cells in suspension showed an increased nitrate reduction when the oxygen concentration was below 0·1 mg l⁻¹. When anaerobically grown cells had been aerated for 24 h in a nitrogen-free medium, the cells became sensitive to respiration inhibition by nitric oxide, resulting from nitrate reduction. This gave rise to an increased nitrate reduction below 2·5 mg oxygen l⁻¹ when the cells were aggregated in flocs and below 0·1 mg oxygen per litre when the cells were in suspension. The nitrate reduction by the denitrifying, floc-forming pure culture was compared with that of activated sludge flocs.     

A survey of Legionella pneumophila in water in 12 Canadian cities

A survey of 12 cities across Canada was conducted in order to determine the prevalence of Legionella species in potable water and cooling tower water within buildings. Legionellae were detected in 11.9% of the samples overall: 6.7% from potable water sources and 28.9% from cooling tower water. The maximum concentration of the organism was 45,000 l⁻¹ in one shower-water sample by culture methods. A significant difference in the isolation rate of Legionella pneumophila among cities was observed. The organism was isolated from waters at a temperature of 15–41°C and was most frequently isolated in the 20–29°C range. The concentration of free and total available chlorine in the water was not associated with legionellae recovery except that the organisms were never recovered when the free available chlorine residual exceeded 7.5 mg l⁻¹. Although L. pneumophila were in low concentrations or absent in most samples, the isolated organisms were usually serogroups 1 or 6, the same serogroups that are most often implicated in legionellosis cases in Canada.     

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 chronic effects of fluoride on the estuarine amphipods Grandidierella lutosa and G. lignorum

The toxicity of fluoride in the estuarine environment was tested, using a mixed culture of the estuarine amphipods Grandidierella lutosa and G. lignorum in life-cycle bioassays. Toxin was dosed in a continuous (intermittent) flow system using a proportional dilution doser. The tests ranged in duration from 39 to 90 days, spanning between 1 and 4 generations in that time. The tests were conducted in sea-water at temperatures of 23–25°C. Background sea-water levels during the experiments fluctuated between 1.3 and 1.7 mg l^−t F′. Improved population increases were detected in fluoride levels slightly above background. Maximum amphipod population increase was measured during three 90-day multi-generation experiments, at a mean fluoride level of 2.64 mg l⁻¹. Population performance returned to levels comparable to control at a mean for the 3 experiments of 5.0 mg l⁻¹ F′. Maximum acceptable toxicant concentration (MATC) was therefore, by definition, set at 5.0–6.2 mg l⁻¹ F′ (mean calculated for three 90-day experiments). Data on female fecundity suggested that the MATC might even be slightly lower, with a mean MATC of 4.15 mg l⁻¹ F′.     

Denitrification with a bacterial disc unit

An enclosed rotating disc unit was operated anaerobically as a denitrifying system, with methanol as the hydrogen donor. As the bacterial population became established, denitrification rate increased by 1·5 mg NO₃⁻—N reduced m⁻² h⁻², to a maximum rate of 260 mg NO₃⁻—N reduced m⁻²h⁻¹. The C:N ratio necessary for complete denitrification was found to be 2·6:1. Optimum pH for denitrification lay in the range between pH 7·0 and 8·5. Q₁₀ values were 1·38 between 10 and 30°C, −2·66 above 30°C and 13·06 below 10°C.     

Effects of copper, zinc and cadmium on Selanastrum Capricornutum

The algicidal and algistatic effects of copper, zinc and cadmium on Selanastrum capricornutum, a unicellular green algae were analyzed by using a modification of the Algal Assay Procedures Bottle Test.Algicidal concentrations of copper, zinc and cadmium were 0.30, 0.70, and 0.65 mg 1⁻¹. Treatment of Selanastrum with various concentrations of the metals resulted in similar growth rates characterized by extended lag growth phases.Combinations of copper, zinc and cadmium were similar in toxicity to equal concentrations of zinc. Combinations of copper and cadmium resulted in a greater growth rate than equal concentrations of copper suggesting that cadmium inhibits copper toxicity.Selanastrum was able to exist in waters from the upper South Fork and North Fork of the Coeur d'Alene River where zinc and other metals were in low concentration. However, the algae was not able to tolerate zinc concentrations greater than 0·5 mg 1⁻¹ from waters of other parts of the drainage. These observations were consistent with laboratory findings where 0.7 mg 1⁻¹ zinc was algicidal and 0.1 mg 1⁻¹ inhibited the growth of Selanastrum.     

Studies on the toxicity of copper sulphate to stone loach Noemacheilus barbatulus (L.) in hard water

The toxicity of copper sulphate to Noemacheilus barbatulus was studied for 64 days in a water of total hardness 249 mg l⁻¹ as CaCO₃. The 63-day lc₅₀ was approximately 0.25 mg Cu l⁻¹. Larger fish survived longer, and at concentrations greater than 0.29 mg l⁻¹ fish hid less during daylight. Noemacheilus surviving 0.12 mg Cu l⁻¹ for 64 days shed copper when placed in clean water for 7 days: gill, muscle, eye and vertebrae lost significant amounts of copper during this period. The opportunity to shed copper during a short period when the poison supply to their tank failed, may have allowed fish exposed to 0.49 mg l⁻¹ to live 12 days longer than expected. The sensitivity of Noemacheilus to copper, cadmium and zinc was compared with that of rainbow trout. Salmo gairdneri.     

Trace metals in the marine bivalve Macoma balthica in the westerschelde estuary, The Nertherlands. Part 3: Variability of the role of cytosol in metal uptake by the clams

Tellinid clams Macoma balthica were sampled every 2 months for 2.5 years at two locations from the Westerschelde estuary (The Netherlands) and submitted to in vitro short-term exposure to Cd, Cu and Zn. Total and heat-stable cytosolic metal concentrations have been measured before and after exposure to study the effects of the sampling season on metal uptake by the bivalve. We observed much higher uptakes of Cd and, to a lesser extent, Cu in winter than in summer, while Zn appears to be constantly regulated. These phenomena are amplified in the cytosol, especially for Cd, a non-essential element, for which the concentrations after exposure can reach 35–45 μg·g⁻¹ (dry wt.) in winter, but only a maximum of 0.5 μg·g⁻¹ in summer, all natural values being between 0.01 and 0.1 μg·g⁻¹ on average. The contents (μg) of the various elements, either at the total or at the cytosolic level, are not constant, hence showing that the seasonal body weight fluctuation of the clams (dilution or concentration effect) is not the only parameter responsible for the metal uptake variability. Furthermore, we have shown that the proportion of cytosolic metal is not constant, but increases with the absolute cytosolic concentration up to 35–40. Therefore, the cytosolic phase of the cells plays a growing role in Cd, Cu and Zn storage as long as their total concentration increases.     

Role of aquatic plants in wastewater treatment by artificial wetlands

This report describes investigations using artificial wetlands which quantitatively assess the role of each of three higher aquatic plant types, Scirpus validus (bulrush), Phragmites communis (common reed) and Typha latifola (cattail), in the removal of nitrogen (via sequential nitrification-denitrification), BOD and TSS from primary municipal wastewaters. During the period August 1983–December 1984, the mean ammonia concentration of 24.7 mg l⁻¹ in the primary wastewater inflow (hydraulic application rate = 4.7 cm day⁻¹) was reduced to mean effluent levels of 1.4 mg l⁻¹ for the bulrush bed, 5.3 mg l⁻¹ for the reed bed and 17.7 mg l⁻¹ for the cattail bed, as compared to a mean value of 22.1 mg l⁻¹ for the unvegetated (control) bed. For all three vegetated beds, the mean effluent ammonia values were significantly below that for the unvegetated bed and for the inflow. The bulrushes and reeds (in that order) proved to be superior at removing ammonia, both with mean effluent levels significantly below that for the cattail bed. The high ammonia-N (and total N) removal efficiencies shown by the bulrush and reed beds are attributed to the ability of these plants to translocate O₂ from the shoots to the roots. The oxidized rhizosphere so formed stimulates sequential nitrification-denitrification. Similarly BOD removal efficiencies were highest in the bulrush and reed beds, both with mean effluent BOD levels (5.3 and 22.2 mg l⁻¹, respectively) significantly below that for the unvegetated bed (36.4 mg l⁻¹) and equal to or better than secondary treatment quality (30 mg l⁻¹). Our results demonstrate that higher aquatic plants can indeed play a significant role in secondary and advanced (N removal) wastewater treatment by wetland systems, a role that is completely distinct from that associated with their pollutant uptake capacity.     

Acute lethality, and sub-lethal effects of acetone, ethanol, and propylene glycol on the cardiovascular and respiratory systems of rainbow trout Salmo gairdneri

Acute lethality and sub-lethal effects of acetone, ethanol, and propylene glycol on the cardiovascular and respiratory systems of rainbow trout (Salmo gairdneri) were examined. The 24 h LC₅₀ values for acetone and ethanol in a flow-through bioassay system at 10°C ± 0.5, are 6100 mg l⁻² and 11,200 mg l⁻¹, respectively. No mortality to fingerling trout was produced by propylene glycol at 50,000 mg l ⁻¹ during a 24 h exposure period in a static system.Acetone and ethanol, at about 0.48 and 0.26 of the fingerling LC₅₀, respectively, affected cardiovascular/respiratory parameters in adult rainbow trout. Acetone produced an increase in ventilation rate to a maximum of 158% of control values, as well as an increase in buccal pressure amplitude attaining a maximum of 410% of control values. Ethanol exposed fish exhibited a slight depression in ventilation rate and buccal pressure amplitude during initial stages of the 24 h exposure period. Ethanol had no effect on heart rate, despite a significant decrease in Q-T interval. Propylene glycol, at less than 0.08 of a concentration not producing apparent stress in fingerlings, had a mildly stimulatory effect on ventilation rate, and heart rate in adults. It is concluded that of the three solvents employed in this study, propylene glycol is most suitable for use as a solvent in fish toxicity tests.     

The effect of surfactants on the extraction-atomic absorption spectrophotometric determination of copper, iron, manganese, lead, nickel, zinc cadmium and cobalt

Nine surfactants representing pure cationic, anionic and non-ionic detergents, three industrially prepared detergents. sodium pyrophosphate. sodium tripolyphosphate, and a soap were investigated for their effect on the extraction-atomic absorption spectrophotometric determination of copper. iron, manganese and lead. Some results are also given for nickel, zinc, cadmium and cobalt. Cations were extracted into 10 ml of MIBK as APDC chelates. To Avoid emulsion formation, maximum concentration of LAS was 1 mg 1⁻¹, and for formulated and non-ionic detergents and washing powders it was 5 mg 1⁻¹.A standard addition procedure was used to obtain correct results for copper and nickel. Two extractions of iron, cobalt and lead, and one extraction of manganese, zinc and cadmium gave a recovery of 100 ± 5%. Soap gave high recoveries for iron and copper. NTA in concentrations up to 25 mg l⁻¹ did not interfere. EDTA in concentrations up to 25 mg l⁻¹ interfered with iron and nickel determinations, but the addition of 3 mg of aluminium removed the EDTA interference in the determination of copper, manganese, lead, zinc, cadmium and cobalt.For the determination of trace metals in polluted natural waters the amount of 4% APDC was increased to 10 ml and for manganese to 25 ml. An addition of 3 mg aluminium as nitrate after the addition of buffer with subsequent 20 min reaction time is required for the determination of all eight metals by the recommended procedures. The effect of humic acid was also investigated.     

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.     

Effect of copper and hexavalent chromium on the specific growth rate of ciliata isolated from activated-sludge

After growing mass and monoxenic cultures of three species of Ciliata (Vorticella microstoma, Colpidium campylum, and Opercularia sp.) with Alcaligenes faecalis as the sole protozoan food, and confirming that copper and hexavalent chromium did not affect the bacterial growth, the effect of these metals on the specific growth rate of each protozoa was examined. The term IL_m (median inhibitory limit) was used to define the metal concentration required to reduce the specific growth rate of protozoa to one-half of that of a control. The IL_m for copper was: 0·25 mg 1⁻¹ (V. microstoma), 0·32 mg 1⁻¹ (C. campylum), and 0·27 mg 1⁻¹ (Opercularia sp.). Regarding hexavalent chromium, IL_m for V. microstoma, C. campylum, and Opercularia sp. were 0·53, 12·9 and 20·2 mg 1⁻¹, respectively. Acclimation of each protozoa to these metals for 96 h resulted in IL_m enhanced values of 1·2–2·2 times as large as that for the control.     

Influence of sediment in copper toxicity tests with the polychaete Neanthes arenaceodentata

Adult male Neanthes arenaceodentata were exposed to measured concentrations of 0.04, 0.06, 0.10, 0.16 and 0.26 mg l⁻¹ Cu in a continuous-flow bioassay system, with and without a clean sand, to assess the influence of sand on Cu induced mortality. The presence of sand did affect the results. The 28-day LC50 was lower for polychaetes exposed without sand than those with sand, 0.044 and 0.10 mg l⁻⁵ Cu, respectively. The reasons for this difference are discussed.