Molluscicidal Activity of Euphorbiales against the Snail Indoplanorbis exustus

Mortality caused to the snail Indoplanorbis exustus by the latices of four species of plants belonging to the family euphorbiaceae has been reported. This snail is the vector of the liver fluke Fasciola hepatica and Fasciola gigantica. It was found that very low concentrations of the latex were effective in killing the snails. The order of toxicity of the four plants was E. royleana > E. antisyphilitica > E. lactea cristata > J. gossypiifolia. The toxic activity of these plants was marginally lost after extraction by organic solvents. The toxic effect of all the plants was both dose and time dependent. It has been suggested that the latex of these plants may eventually find use as molluscicides in the field.     

Acute and Chronic Toxic Effects of Cadmium on some Haematological,Biochemical, and Enzymological Parameters in the Fresh Water Teleost Fish Channa punctatus Akute und chronisch toxische Wirkungen von Cadmium auf einige hämatologische,biochemische und enzymologische Parameter im Süßwasserfisch Channa punctatus

The haematological, biochemical, and enzymological alterations produced on exposure of Channa punctatus to LC₅₀ (11.2 mg/L) for 96 h and to a sublethal concentration (1.12 mg/L) of cadmium (Cd²⁺) for 15, 30, 60, and 120 days have been studied. The fish were hypoglycemic and hypolactemic. The pyruvate content of blood and liver decreased in acute and all stages of chronic exposure except for 30 days where significant increase was recorded. Depletion was noted in the total protein and glycogen content of liver and muscle, and the level of lactate in liver in the two types of exposure. The levels of muscle lactate and pyruvate increased in both exposures. The activities of hexokinase, glucose-6-phosphatase, and lactate dehydrogenase decreased in liver after 96 h and all stages of chronic exposure except 30 days. The activities of hexokinase and lactate dehydrogenase in muscle and glutamate-oxalacetate transaminase and glutamate-pyruvate transaminase in serum, liver, and muscles increased in all exposures. The activities of succinate and malate dehydrogenases in liver and muscles decreased after acute and all stages of chronic exposure. The above results suggest that glycolysis and gluconeogenesis were impaired in liver but glycolysis prevailed in muscle. Aerobic oxidation is adversely affected in metal exposed fish, while proteolysis was increased.     

Plasma pressure distribution in the equatorial plane of the Earth’s magnetosphere at geocentric distances of 6–10<Emphasis Type="Italic">R</Emphasis><Subscript><Emphasis Type="Italic">E</Emphasis></Subscript> according to the international THEMIS mission data

The structure of the averaged plasma pressure distribution in the plasma ring around the Earth at geocentric distances of ∼6–10R _E has been determined. The distribution function moments measured on the international THEMIS mission satellites have been used. The plasma pressure distribution in the equatorial plane at 15R _E > X_SM > −15R _E and 15R _E > Y_SM > −15R _E has been statistically studied. The radial dependence of the plasma pressure at the day-night and morning-evening meridians has been analyzed. It has been indicated that the plasma ring around the Earth has a structure, which is close to being azimuthally symmetric. The achieved results have been compared with the pressure distributions obtained previously. It has been indicated that in the overlapping regions, the achieved results agree with the previously obtained data within the pressure determination errors.     

不同碳磷比的斜生栅藻(Scenedesmus obliquus)对同型溞(Daphnia similis)生长和繁殖的影响

食物质量会影响浮游动物的生长和繁殖,表征食物质量的指标包括食物大小、元素比、生物化学组成和毒性有无等.用斜生栅藻(Scenedesmus obliquus)的碳磷比(C/P)表征食物质量,分析不同C/P斜生栅藻对同型溞(Daphnia similis)生长和繁殖的影响.研究中4个处理组斜生栅藻C/P分别为881.8、512.3、124.3和42.4.培养9 d后不同处理组同型溞的生长速率分别为0.15、0.27、0.47和0.44 d-1.C/P比为881.8的处理组同型溞在整个培养过程中没有产仔,其余3个处理组的同型溞第1成龄期的产仔量分别为1.2±1.3、9.8±2.3和9.5±2.5 ind./female.结果表明,与斜生栅藻C/P为124.3处理条件相比,斜生栅藻C/P过高(512.3和881.8)及C/P过低(42.4)处理条件下同型溞生长速率和产仔量均降低.本研究表明食物C/P的高低会影响溞的生长和繁殖,从而影响其在湖泊中的生存.     

Localization of Branchial Enzymes and their Significance in the Detection of Crude Oil Toxicity in Colisa fasciatus

The effect of crude oil on the histochemical localization of branchial enzymes CA, SDH, LDH, Alkpase and Acidpase was investigated in Colisa fasciatus. The activity of all the enzymes experimented here was found to have decreased when treated with the lethal solutions of crude oil except the LDH which showed an increasing trend throughout the experiment. A transitory increase in the CA and SDH was observed in the beginning but reached an almost normal level after 48 h in 1000 ppm. On the basis of sensitiveness towards crude oil toxicity, the enzymes have been arranged in the following order: LDH > SDH > CA > Alkpase > Acidpase. The results suggest that crude oil is capable of impairing the enzyme activity. The decreased or increased level of enzymes may be used as an indicator for assessing the toxicity of oil pollutants.     

Dynamic Parameters of Plant Communities Partially Reflect the Soil Quality Improvement in Eco‐Reclamation Area of an Opencast Coal Mine

The influence of soil physicochemical properties and the relationship between the plant community and edaphic factors have been studied through monitoring the community dynamic parameters and analyzing the soil properties from four plant plots at the Pingshuo opencast coal mine eco‐reclamation area. The results are obtained as follows: (1) the law of the quantity variation of total N and available K is affected by the different kinds of plant configuration mode. It is Robinia pseudoacacia + Pinus tabuliformis (SIV) > R. pseudoacacia (SV) > R. pseudoacacia + P. tabuliformis (SI) > R. pseudoacacia + Ulmus pumila + Ailanthus altissima (SIII). The quantity is close to or exceeds the level of the original geomorphology. The average content of available N has the following order: SIV > SI > SIII > SV; the average content of available P SV > SIII > SIV > SI, both are far below the level of the original geomorphology; pH SIV < SIII < SI < SV; bulk density SI < SIV < SV < SIII, moisture content SIV > SIII > SI > SV; in the soil layer of 20–40 cm, except the available P, other physicochemical factors are in accordance with the factors of the surface soil; (2) the population average density, height and diameter at breast height (DBH) have no obvious relevance with the average density of the stumpage; (3) the average density, height, and DBH of R. pseudoacacia are closely related to pH and the content of available N and available P and all the index can be fitted by the equation of linear regression of the edaphic factors mentioned above. The principal component analysis shows that the magnitude of the impacts of three kinds of edaphic factors on the R. pseudoacacia population has the following order: pH > available N > available P. The average density of U. pumila is closely related to the moisture content of the soil. This regression model can be used to direct the cultivation and propagation of R. pseudoacacia and U. pumila population at the mine eco‐reclamation area.     

Comparative Toxicity of Certain Non-Insecticidal Chemicals to Mesocyclops leuckarti,the Carrier Host of Dracunculosis

The relative toxicities of seven non insecticidal chemicals to Mesocyclops leuckarti were tested. The relative toxicity of each chemical is given as under: Chlorine water > Potassium permanganate > Cetavlon > Quicklime > Common alum > Savlon > Sodium bicarbonate.     

微囊藻毒素生物学功能研究进展

我国淡水水体蓝藻水华的频繁发生已成为我国目前和今后长时期内面临的重大水环境问题.微囊藻(Microcystis)因其产生对人类健康具有危害的微囊藻毒素而尤其受到重视.研究者对构成蓝藻水华的主要种类、微囊藻毒素的毒性、毒理等方面的认识逐渐明晰,但对微囊藻毒素生物学功能的了解还相对较少.本文对微囊藻毒素的产生,尤其是近年来随着技术的发展在微囊藻毒素生物学功能方面的研究开展讨论:总结了微囊藻毒素可能作为化感物质、参与光合作用、在微囊藻的越冬或复苏中可能发挥的作用以及可能参与微囊藻群体形成及维持等4个方面的生物学功能;分析了微囊藻毒素作为信号分子的研究现状;探讨了全球气候变化及实验室模拟条件下微囊藻毒素产毒与无毒株的竞争,并对微囊藻毒素未来的研究热点及组学技术可能在其研究中的应用进行了展望.     

Carcinogenic Risk Assessment of Trihalomethanes in Major Drinking Water Sources of Baghdad City

Three standard methodological approaches used for carcinogenic risk assessment of the four trihalomethanes (THMs) species: Dibromochloromethane (CHClBr₂), Bromodichloromethane (CHCl₂Br), Bromoform (CHBr₃) and Chloroform (CHCl₃), in water collected from public water supplies which included main water source (raw water of the Tigris River), water treatment plants (treated water) and distribution system (tap water) in Baghdad City. The total concentration of THMs ranged between 13.78 and 63.1 μg/L in winter and summer respectively. The occurrence of THMs followed the given order: CHClBr₂ (36%) > CHCl₂Br (27%) > CHCl₃ (25%) > CHBr₃ (12%). The annual levels of THMs concentrations in the distribution networks of Baghdad City ranged between 12 and 97.3 μg/L in winter and summer, respectively, and followed the given order: CHClBr₂ (37%) > CHCl₂Br (33%) > CHCl₃ (21%) > CHBr³ (9%). The World Health Organization (WHO) index for additive toxicity approach was in compliant with the WHO guideline value, and does not pose any adverse toxic health impacts. The hazard index does not suggest any potential noncancer risk to the exposed population, whereas the total multi-pathway cancer risk analysis suggests that total cancer risk exceeds the USEPA acceptable level of 10–6.     

Determination of Partition Coefficients of Metals in Natural Tropical Water

The values for the partition coefficient (K_d) were calculated for Ca, Mg, Cd, Cr, Cu, Fe, Mn, Pb, Ni, and Zn at 19 sites in the Capivara hydroelectric reservoir in Brazil. It was found that the relative values of K_d follow the order: Cr > Mn > Fe > Cu > Zn > Ni > Pb > Ca > Cd, differing from the values reported for K_d in aquatic systems in the northern hemisphere. A hierarchical cluster analysis and linear correlations showed that Cr is strongly associated with Fe and Cu, and that Cd is the only metal found in complexation with organic matter, explaining its higher solubility.     

Use of a harpacticoid copepod in toxicity tests

The harpacticoid copepod Nitocra spinipes has been tested for acute toxicity of 12 metal chlorides in brackish water. Their order of toxicity, expressed as 96 h LC₅₀, was in good agreement with other investigations performed in freshwater and seawater. The 96 h LC₅₀-values were of intermediate levels compared to these two environments. The organochlorines p,p′-DDE and p,p′-DDE methyl sulphone were tested for effects on reproduction and mortality during two weeks, and it was found that p,p′-DDE was the most toxic. It is concluded from the investigation that N. spinipes is a suitable toxicity test organism in brackish water.     

Variations in the amplitude of the chandler wobble

It is shown that within the framework of the Kolmogorov model the “energy” of the pole E(t) = x ₁² + x ₂² can be interpreted as a Markovian process. The exact analytical expression has been obtained for the density of the conditional probability of the quantity E(t) and the problem of the first passage time of the process E(t) has been analyzed. It was shown that the available data on the swing of the function E(t) are not at variance with the Kolmogorov model and a short-period drop of the amplitude of the Chandler wobble in the early 20th century fits this model at Q = 50–200 too; values of Q > 350 are less reasonable.     

Nuclear Morphology and Lysosomal Stability of Molluskan Hemocytes as Possible Biomarkers of Arsenic Toxicity

The frequency of nuclear aberrations and neutral red retention time of hemocytes in the mollusk Lamellidens marginalis were recorded under exposure to sublethal concentrations of sodium arsenite in order to examine the sensitivity and effectiveness of these inexpensive assays for screening the toxicity of As³⁺ in a freshwater ecosystem. A dose and time dependent increase in the density of micronucleated and binucleated hemocytes and gill cells was indicative of the pronounced genotoxic effect of arsenic on this animal. The disruption of intrahemocyte homeostasis imposed by this natural toxicant was evident from a dose and time dependent reduction in the lysosomal stability of the hemocytes of the animal. The tested parameters are indicative of arsenic toxicity in L. marginalis in the freshwater systems of the arsenic affected geographical areas of West Bengal, India.     

Primary Productivity Studies on Freshwater Fish-Ponds of Bhagalpur,India

A one year study from October 1972 to September 1973 in four freshwater fishponds of Bhagalpur (87° 02' E long, and 25° 15'N lat.), India, has shown that a high phytoplankton primary production occurred twice during the annual cycle. There were seasonal variations in the production rate with a great fluctuation in the maximum and minimum values (3 … 4 times). Amongst the ponds studied, the highest daily production recorded was 6.93 g C/m²/day in Pond I and the minimum was 0.82 g C/m²/day in Pond II. The highest annual gross production was estimated to be 1611.98 g C/m²/y in Pond I, next in the order was 1543 g C/m²/y in Pond IV and then 1155.7.5 g C/m²/y in Pond I and the minimum was 641.75 C/m²/y in Pond II. It has also been observed that in certain months the net:gross ratio recorded was zero, while the community respiration as percentage of the gross production value reached 100% in few months. A comparison has been made in the annual production of temperate and tropical freshwater systems and this indicates that tropical waters are more productive than the temperate waters. Various physico-chemical factors such as rainfall, light, temperature and alkalinity may regulate or limit production.     

Response of dayside auroras to abrupt increases in the solar wind dynamic pressure at positive and negative polarity of the IMF <Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">z</Emphasis></Subscript> component

The optical observations on Heiss Island (Φ′ = 75.0°) have been used to study the characteristics of auroras in the near-noon MLT sector after abrupt increases in the solar wind dynamic pressure at negative and positive polarity of the IMF B _z component. It has been found out that the 427.8 and 557.7 nm emission intensities considerably increased at B _z < 0 both equatorward of the dayside red luminosity band and within this band. The value of the emission intensities at a red luminosity maximum (I ₆₃₀₀/I ₅₅₇₇ ∼ 0.5) indicates that energetic electron precipitation is of the magnetospheric origin. At B _z > 0, fluxes of harder (E > 1 keV) precipitating electrons were superimposed on the soft spectrum of precipitating particles in the equatorial part of the red luminosity band. This red band part was hypothetically caused by the low-latitude boundary layer (LLBL) on closed lines of the geomagnetic field, the estimated thickness of which is ∼3 R _e . The 557.7 nm emission intensity increased during 3–5 min after SC/SI and was accompanied by the displacement of the red band equatorward boundary toward lower latitudes. The displacement value was ∼150–200 km when the dynamic pressure abruptly increased by a factor of 3–5. After SC/SI, the 630.0 nm emission intensity continued increasing during 16–18 min. It is assumed that the time of an increase in the red line intensity corresponds to the time of saturation of the magnetospheric boundary layers with magnetosheath particles after an abrupt increase in their density.     

Some Advantages of the Duckweed Test to Assess the Toxicity of Environmental Samples

In Germany, wastewater legislation requires all municipal and industrial leachate to be subjected to toxicity tests. However, no phytotoxicity tests using higher plants are currently included among the standard tests. Freshwater microalgae have been used in most phytotoxicity tests and have often been considered as surrogates for higher plants. However, microalgae often do not show the same sensitivity as higher plants and have major disadvantages for the testing of unmodified environmental samples. In the following study, we evaluated the suitability of the giant duckweed Spirodela polyrhiza for assessing the toxicity of a municipal landfill leachate and two leachates of copper mining residue. Duckweed static toxicity tests were performed, and frond number was the endpoint used to calculate EC₅₀ values. Symptoms of stress (chlorosis, necrosis, root destruction, and colony breakup) were also recorded. The landfill leachate was toxic with EC_50;96h values ranging from 1.3 to 2.7% leachate (v/v). Toxicity of the copper slag leachate was largely determined by the elution method used. Leachate obtained using conventional German leaching methods (S4-eluate) was not toxic to duckweed, whereas EC₅₀ values for the pH_stat4-eluate ranged from 3.2 to 4.2% leachate (v/v). The results demonstrate the suitability of S. polyrhiza for the testing of unmodified wastewater samples and provide further evidence for the addition of a duckweed toxicity test to the standard tests conducted in Germany.     

Influence of Polyphenols and Quinones on Aquatic Plants and Their Blocking of SH-Groups

The influence of dioxybenzenes and their quinones on Dunaliella salina, Nitella sp. and Elodea canadensis was investigated. It was established that the higher the rate of polyphenol oxidation by the aqueous plants, the higher the toxicity of the compound being studied is and the larger the reduction of the SH-group content due to the incubation of plants in these polyphenol solutions is. Formation of o- and p-benzoquinones by the aquatic plants in the course of dioxybenzene oxidation was proved. Treatment of plants with quinone solutions led to a larger SH-group concentration drop than with phenols. Oxidation products of pyrocatechol, caffeic and chlorogenic acids caused the greatest decrease of the SH-group content directly at the moment of their preparation, i. e., when the o-quinone concentration was at its maximum. The conclusion is drawn that a higher degree of toxicity to the aquatic plants of pyrocatechol and hydroquinone, in comparison with other phenols, is due to their ability to oxidize phenols to quinones. It is suggested that one of the possible biochemical mechanisms for demonstrating the toxic action of the phenol oxidation products is the blocking of SH-groups.     

Effect of Individual Phenolic Compounds and of Their Mixtures on Luminous Bacteria. Part 3. Combined Action of Phenolic Compounds on Aquatic Organisms

Data on the action of mono- and polyatomic phenol mixtures on hydrobionts are discussed. Luminescent bacteria, Daphnia, algae zoospores, higher aquatic plants–Elodea and duckweed – were used as test objects. It is established that the toxicity of a paired mixture of mono- and polyatomic phenols is lower than the toxicity of their components.     

Integrated assessment of lateral flow, density effects and dispersion in aquifer storage and recovery

Aquifer storage and recovery (ASR) involves the injection of freshwater into an aquifer for later recovery and use. This paper investigates three major factors leading to reduction in performance of ASR systems in brackish or saline aquifers: lateral flow, density-driven flow and dispersive mixing. Previous analyses of aquifer storage and recovery (ASR) have considered at most two of the above processes, but never all three together, and none have considered lateral flow and density effects together. In this analysis, four dimensionless parameters are defined to give an approximate characterisation of lateral flow, dispersive mixing, mixed convection (density effects during pumping) and free convection (density effects during storage). An extensive set of numerical models spanning a wide parameter range is then used to develop a predictive framework using the dimensionless numbers. If the sum of the four dimensionless numbers (denoted R_ASR) exceeds 10, the ASR operation is likely to fail with no recoverable freshwater, while if R_ASR < 0.1, the ASR operation is likely to provide at least some recovery of freshwater. The predictive framework is tested using limited data available from ASR field sites, broadly lending support to the framework. This study has several important implications. Firstly, the lack of completeness of field data sets in the literature must be rectified if we are to properly characterise mixed-convective flow processes in ASR operations. Once data are available, the dimensionless numbers can be used to identify suitable ASR sites and the desirable operational conditions that maximise recovery efficiencies.     

A comparative study of toxicity identification using Daphnia magna and Tigriopus japonicus: Implications of establishing effluent discharge limits in Korea

In Korea, the new permission criteria for industrial effluents based on Daphnia magna acute toxicity tests will be gradually implemented starting from 2011. Thus, in this study, toxicity assessment and identification using a marine species (Tigriopus japonicus) and the freshwater species (D. magna) was comparatively investigated. Effluent from an acid mine drainage treatment plant showed acute toxicity toward both organisms due to low pH, which was removed by neutralization of the effluent. Additionally, evaluation of the effluent of an electronics company revealed that Cu was attributable to the observed toxicity, and the effluent was more toxic toward T. japonicus than D. magna. Moreover, effluents from a metal plating factory were acutely toxic toward D. magna (6.50 TU), while they were not toxic against T. japonicus. Toxicity identification revealed that the high level of Cl⁻ (12,841 mg L⁻¹) was the cause of toxicity. Thus, the effluents had no effect on the marine species, T. japonicus. These findings suggest that a marine species rather than a freshwater species is more desirable for toxicity assessment of industrial effluent discharged into the saltwater, and thus should be considered in the legislation of toxicity-based discharge limits in Korea.