Chlorination of Humic Acids and Chloroform Production

By diluting a boggy water there is produced water with a COD-Mn of 3.4 … 10.6 mg/l O₂ which is due only to humic substances. The water is mixed with 2.5 … 12.9 mg/l Cl₂ at pH-values of 5.2 … 8.5 and incubated for 24 h at 20°C. CHCl₃ concentrations of 38 … 480 μg/l were found by the subsequent gas-chromatographic determination. The production of chloroform can be calculated by means of a quadratic polynomial in dependence on COD-Mn, chlorine concentration and pH-value.     

Toxicity of Phenol,Pentachlorophenol and Sodium Pentachlorophenolate to a Freshwater Teleost Lebistes reticulatus (Peters)

Lebistes reticulatus (Peters) was exposed to various concentrations of phenol, pentachlorophenol and sodium pentachlorophenolate to determine their toxicity, lethal concentrations and slope functions by a static bioassay procedure. Simultaneous controls were also run. The 94h LC₅₀ values were 47.5mg/l (42.04 … 53.68) for phenol, 0.77 mg/l (0.616 … 0.963) for sodium pentachlorophenate and 0.97 mg/l (0.866 … 1.086) for pentachlorophenol. On this basis, the rank order is sodium pentachlorophenolate-pentachlorophenol-phenol. During the treatment, fish showed an abnormal swimming reflex, excessive mucus secretion, haemorrhage near lips, abdomen and basis of fins and loss of equilibrium followed by death.     

Acute Toxicity of Distillery Effluent on a Freshwater Fish and Three Pond Snails

The LC₅₀ for 12… 96 h of a distillery waste water were determined for Lebistes reticulatus, Lymnaea luteola, Lymnaea acuminata and Viviparus bengalensis in the batch experiment with daily exchange of the medium. The sensitivity of the species increases in the given sequence with values of the LC_{50,96 h} of 10.77 to 3.72 % proportion of wastewater in the medium. Compared with this, with values of the LC_{50,48 h} of 14.06… 15.71 % after 48 h of exposure there is no significant difference in sensitivity, whereas after exposure for 12 and 24 h the sensitivity grows in the following order: V. bengalensis, L. acuminata, L. luteola, Lebistes reticulatus. Toxicity is obviously primarily determined by the sulphides; with increasing time of exposure also the suspended matter and other factors act toxically.     

Studies on the Acute Toxicity of Zinc to a Freshwater Teleost: Channa punctatus (Bloch)

Static bioassay tests were carried out on Channa punctatus Bloch in the laboratory after renewal of concentrations every 24 h. The LC₅₀ values and 95 per cent confidence limits were 45.21 (39.62 … 51.11) ppm at 12 h and 29.8 (27.49 … 31.95) ppm of Zn at 96 h of exposure. The actual dissolution values of zinc were also determined in test solutions using an atomic absorption spectrophotometer. Behavioural changes were the higher rate of opercular movements, surfacing, loss of equilibrium and haemorrhage near mouth and caudal fin. The LT₅₀ values indicate that survival was increased with decreasing Zn concentration. The histopathological changes observed due to Zn toxicity in the gills have been discussed in relation to fish mortality.     

Deleterious effects of Malathion on survivality and growth of the fingerlings of Channa punctatus (BLOCH.), a freshwater murrel

The LC₅₀ of Malathion for Channu punctatus is determined for 24… 96 h of exposure as 10.95… 3.22 mg/l. At exposure to 2.5 mg./l Malathion, growth–measured by increase in weight–is significantly reduced from the 19th day and reduced by 10 % till the 31st day. During the same period of time, the RNA and protein contents of the muscle is lowered by 10 and 15 %, respectively, as compared with the control. In addition to an acute toxic effect, in sublethal concentrations Malathion has also pronounced effects on growth and metabolism.     

Effect of Zinc,Copper and Mercury on Channa marulius (HAMILTON)

Static bioassay acute toxicity tests of Zinc, Copper and Mercury were conducted to determine the median lethal concentrations (LC₅₀s) of a freshwater teleost Channa marulius (HAM .) The 96 h LC₅₀ and 95% confidence limits for Zn²⁺ were 25.61 (24.13 … 27.12) mg/l; 0.90 (0.80 … 1.038) mg/l; for Cu²⁺ and 0.314 (0.257 … 0.371) mg/l for Hg²⁺. However, these values decreased at 240 h of exposure and were: 21.09 (18.29 … 24.60) mg Zn²⁺/l; 0.66 (0.568 … 0.841) mg Cu²⁺/l; and 0.131 (0.103 … 0.158) mg Hg²⁺/l. The relative potency ratio of Zn/Hg, Zn/Cu and Cu/Hg suggests that fish were most sensitive to Hg, followed by Cu and Zn ions. The acute toxicities of mixtures of Zn²⁺?Cu²⁺; Zn²⁺?Hg²⁺, Cu²⁺?Hg²⁺ and Zn²⁺?Cu²⁺?Hg²⁺ up to 48 h of exposure were also investigated. The additive index and ranges for Zn²⁺?Cu²⁺ were ?0.241 (-0.577 … 0.054); 0.056 (-0.269 … 0.475) for Zn-Hg; 0.285 (-0.043 … 0.718) for Cu-Hg; and -0.542 (-1.215 … 0.005) for Zn-Cu-Hg. All the mixtures tested showed a greater than additive toxicity because index ranges overlapped zero.     

Effect of Complexing Agents on the Acute Toxicity of Copper to Common Guppy Lebistes reticulatus (PETERS)

The acute toxicity of copper and copper plus complexing agents to common guppy Lebistes reticulatus was studied for 96 h by a static bioassay technique. The addition of complexing agents viz. disodium salt of EDTA, citric acid, sodium thiosulphate and glycine in Cu²⁺ solutions caused a great decrease in the per-cent mortality as compared to that of Cu²⁺ test solutions alone. 10 mg/l of complexing agent was added in each copper concentration in all the test series. The 96 h LC₅₀ values and 95% confidence limits in mg/l of Cu²⁺ plus were 1.23 (0.95…1.65) for Cu²⁺ alone; 4.30 (4.04 … 4.55) for Cu²⁺ plus EDTA; 1.94 (1.69 … 2.18) for Cu²⁺ plus citric acid; 3.44 (2.96 … 3.74) for Cu²⁺ sodium thiosulphate and 2.29 (2.22 … 3.02) for Cu²⁺ plus glycine.     

Diazinon Toxicity: Activities of Acetylcholinesterase and Phosphatases in the Nervous Tissue of Zebra Fish,Brachydanio rerio (Cyprinidae)

The LC₅₀-value of diazinon for Brachydanio rerio decreases from 2.3 to 2.12 mg/1 during the time from 24 to 96 h. In the course of exposure for 24 to 288 h against 0.26 to 2.08 mg/1 diazinon the activity of acetylcholinesterase as well as acid and alkaline phosphatases decreases to 20.… 30% as a minimum. The decrease of the enzymatic activities in the brain tissue is more time-dependent than concentration-dependent, which may de due to the respective metabolites of diazinon.     

Short Term Effects of Aldrin and Swascofix CD-38 on the Feeding and Respiratory Behaviours of Clarias batrachus and Cirrhina mrigala

Fish were kept in non-toxic water or at 0.5, 0.25 and 0.125 of the LC_50,96h of the ten-side or insecticide for 24 h and fed with toxified and non-toxified feed. Toxified feed in normal water resulted in a maximum feed intake, while normal feed in toxified water resulted in a minimum one. In each case, the feed intake was lower compared with the control, and the feed intake was inversely proportional to the toxicant concentration. In a simple respirometer the oxygen consumption in mg · kg^?1 · h^?1 was tested for 1, 2, 4, 6, 8, 10, 12, 24, 36, 48, 60, 72, 84 and 96 h of exposure to 1.5, 1.0 and 0.5 of the LC_50,96h of both substances. It was a flow device which was closed only for measurement for one hour. 1.5 LC₅₀ Aldrin causes a continuous reduction of respiration until death. The same effect occurred with Cl. batrachus for 1.5 LC₅₀ of the tenside, whereas with C. mrigala death was caused by a pronounced increase of respiration. In all other cases, after a phase of sensitization for 4 … 8 h respiration increased considerably to more than 300% of the control, which was followed after 12 … 24 h by acclimatization to normal respiration values.     

Einsatz einer konstruierten Mischkultur zur Verwertung von Mischsubstraten mit inhibierend wirkenden Substanzen

By way of introduction the general fundamentals and kinetic setups of the competitive and non-competitive as well as substrate inhibition of cultures of microorganisms are stated. Investigated on a laboratory scale is the degradation of liquid pig slurry in a 600-1 stirring fermenter with discontinuous addition (pO₂≧=30 = saturation) of methanol as external substrate by a yeast mixed culture of Metschnikowia and Pichia membranifaceans to utilize the steam-volatile fatty acids (12 g/l) and of Acetobacter methanolicus to utilize methanol. A stable fermentation with stable residual concentrations of 235 mg/l fatty acids, 142 mg/l mH₄-N an 100 … 300 mg/l methanol for aperiod of 2400 h can be achieved.     

Daphnia magna as a Model to Assess Heavy Metal Toxicity: Comparative Assessment with Mouse System

The acute static bioassays with heavy metals at 13 ± 1.5 °C in hard water (total hardness = 240 ppm as CaCO₃) were conducted in the laboratory with Daphnia magna. The 48 hr LC values and their 95 per dent confidence limits in ppm of metal were: 0.0038 (0.0027… 0.0053) for Hg; 0.015 (0.009… 0.026) for Ag; 0.1 (0.063… 0.16) for Cu; 0.69 (0.48… 1.0) for Zn; 1.52 (1.01… 2.28) for Co; 1.8 (1.16… 2.70) for Cr; 1.5 (1.07… 2.1) for Cd; 2,63 (1.7… 4.08) for Pb; 7.3 (5.49… 9.71) for Ni and 19.5 (13.45… 28.3) for Sn. At the close of 24 h of exposure Zn and Cd solutions showed milky white precipitation. The order of toxicity of heavy metals in this model was: Hg>Ag>Cu>Zn>Cd>Co>Cr>Pb>Ni>Sn. Comparison of D. magna and mouse LC₅₀ data showed that Daphnia were sensitive at 1/2710, 1/83, 1/123 and 1/5.5, the LC₅₀ values of Hg, Cu and Zn, respectively. Toxicity test with D. magna is simple, requiring less space, time, facilities, acclimatization time and equipment. Furthermore, Daphnia is more functional, reliable and gives reproducible results. Based on this data we believe the Daphnia magna model can be used as a model to study heavy metal toxicity.     

Aldrin Induced Changes in the Activities of Three Phosphatases of Macrobrachium lamarrei (H. Milne EDWARDS)

Macrobrachium lamarrei is exposed to 0.008, 0.017 and 0.021 mg/1 aldrin (0.4, 0.8 and 1.0 of the LC_50,96h) for 24… 96 h and after exposure the activities of the acid, alkaline and glucose-6-phosphatases are determined. With concentration and time of exposure the acid phosphatase shows an increasing activity up to 170 % compared with the control, which is interpreted as a part of prenecrotic changes in the cells. With concentration and time of exposure the alkaline phosphatase shows a decreasing activity down to 20 % of the control, which is indicative of considerable disturbances of the total metabolism. The glucose-6-phosphatase shows an increasing activity with the aldrin concentration up to 150 % during 72 h; then the activity drops to 60… 80 %. The initial rise in the glucose concentration of blood caused by that is the clear consequence of a stress reaction and the change of metabolism resulting from it.     

Effect of lethal concentrations of copper on Mystus bleekeri (day)

In the batch test with daily exchange of medium the effect of copper ions at 2.4 mmol/l (Ca²⁺ + Mg²⁺) over 10 d of exposure is investigated. The LT₅₀ values and 95% confidence limits at 3.7, 2.1 and 1.0 ppm of Cu were 26.7 (23.6… 29.9), 47.5 (39.6… 57.0) and 101.5 (78.5… 130.7) h, respectively. The LC₅₀ values of copper in ppm were 4.05 (24 h), 1.69 (48 h), 0.829 (9.96 and 0.776 (240 h).     

Histochemical Observation on Crude Oil Poisoning in the Respiratory Epithelium of Puntius sophore

The sensitivity of respiratory mucus cells to the aqueous extracts of 200… 2000 ppm of crude oil has been determined in Puntius sophore using histochemical techniques. The results indicate the mucus cells to be highly susceptible to the crude oil poisoning in both lethal and sublethal concentrations. Sublethal extracts induce excessive mucus production and form a protective covering over branchial epithelia. Lethal extracts, however, reduce the number and size of the mucus cells causing scanty mucus secretion in short-term exposure (≦4 h), but degenerate the mucus cells when the exposure period is prolonged (≧12 h).     

Acute Toxicity of Phenol,Pentachlorophenol and Sodium Pentachlorophenate to a Freshwater Ostracod Cypris subglobosa (Sowerby)

The toxicity of phenol, pentachlorophenol and Na-pentachlorophenate to Cypris subglobosa is determined in the batch experiment for 96. h. In the sequence mentioned, the LC_50,96h of the three substances are 71.8, 6.56 and 4.41 mg/l, respectively. In the range of 6 … 95 h the mean survival time shows a negative regression to the toxicant concentration, which, however, is not significant statistically for Na-pentachlorophenate. In agreement with this, the LC₅₀ for 12, 24, 48, 72 and 96 h of exposure shows a significant decrease. Due to the comparatively high LC_50,96h for pentachlorophenol and Na-pentachlorophenate for C. subglobosa about in comparison with fish, the species is little suited to the toxicological investigation of wastewater.     

Phosphoraufnahme durch Potamogeton natans und submerse Makrophyten in einem Fließgewässer-Laboratoriumsmodell

The germs of macrophytes were exposed in a ring channel at 0.073 m/s, 0.085 m water level and natural daylight for 52 h in tap water whose phosphorus concentration had been increased with KH₂PO₄ to 0.325 mg/1 P. After 4, 28 and 52 h the phosphorus concentrations in water and in dry matter were determined and the relative phosphorus elimination and incorporation, as referred to the concentrations in water and in dry matter prior to the test, were calculated in 0/0. Within 52 h the following increases of the internal phosphorus pool resulted (in %): Ranunculus aquatilis April 141, Potamogeton crispus May 178, P. natans June 139, Callitriche polymorpha June 128, Ranunculus aquatilis August 118, Elodea canadensis September 124. The phosphorus uptake behaves thus parallel to the gas-metabolism-physiological activity and the subsequently made differentiation into species which are active in spring, summer and autumn. Therefore, weed removals from waters should be done at the date of the species-specific activity maximum, since the then obtained biomass with 3… 9 kg/t P in the dry matter guarantees a maximum phosphorus elimination from the water.     

Zur Konzentrationsabhängigkeit der Sorption von Co(II) an Titanschwamm

The sorption of Co(II) from aqueous solutions on granulated titanium dioxide was investigated in dependence on pH-value (pH = 6 … 10) and solution concentration (c_L = 10^?7 … 10^?2 mol/kg) at 83 °C. The precipitation in the solution occurred at high pH-values and solution concentrations was determined by control experiments without the adsorber. The adsorption isotherms are S-shaped. This can be interpreted as transition from chemisorption at the basic material to surface precipitation.     

Zum Auftreten von leichtflüchtigen Halogenkohlenwasserstoffen im Badewasser

110 samples from two swimming-pools were gas-chromatographically investigated for halogenated hydrocarbons. In spite of varying chlorine concentrations between 0.1 and 2.5 mg/l Cl₂ the bacteriological results were unobjectionable. The total of the haloforms was between 1.2 and 182 μg/l, with the average value of 90 μg/l. Besides CHCl₃, CHBrCl₂, CHBr₂Cl and CCl₃NO₂ there were observed other, still unidentified compounds in the chlorinated bathing water which clearly are successive products of disinfection, too. The water treatment by flocculation and filtration does not bring about any elimination of trihalomethanes. Of special importance is the occurrence of trichloronitromethane in concentrations of 0.13 … 1.2 μg/l, whose LC₅₀ in the Daphnia test is 189 μg/l, at a threshold concentration of 160 μg/l. To limit the pollution of water and air to a minimum, specific conditions must be adhered to in the operation of indoor swimming-pools.     

Survivality and Impaired Growth in Arsenic Treated Fingerlings of Channa punctatus,a Fresh Water Murrel

The LC₅₀-values of As³⁺-compounds for Channa punctatus are determined for a 48-h exposure to 19.4 (18.02… 21.3) mg/1 and for a 96-h exposure to 14.3 (13.06… 16.80) mg/1. At a long-time exposure to 7.0 mg/1 As³⁺, during the first seven days there does not occur any change of growth, then the growth in length and the increase in weight decreased by 6.6 and 11.7%, respectively, till the 31st day. At the same time, the RNA content of the muscle decreased by 11.5% to 966.7 μg/g fresh weight and the protein content decreased by 12.5 % to 95.39 mg/g fresh weight.