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1.
The effect of ascorbic acid and pesticides (thiotox and malathion) on certain haematological parameters of a fishSaccobranchus fossilis was studied. The sublethal concentrations of thiotox (0.002 mg l?1) and of malathion (5.2 mg l?1) were tested. Ascorbic acid (2mg 100 g?1 body weight) was given with food. The alterations in haematological parameters (CT, PT, Hb, RBC, WBC, ESR, PCV, MCH, MCHC, MCV, glucose, protein, total P, Na, K, Mg, Ca, and Cl) were measured after 15 and 30 days exposure. Thiotox and malathion induced significant alteration in blood parameters while ascorbic acid played a protective role.  相似文献   

2.
Fish Saccobranchus fossilis were exposed to various subacute levels (0.45, 0.56, 0.75, 1.12, and 2.24 mg l?1) of sodium lauryl sulphate (SLS) for periods of 30 and 60 days, and the haematological response in blood was investigated. A significant fall (P < 0.05) in coagulation time was observed after 30 days exposure to 2.24 mg l?1 and 60 days exposure to 1.12 and 2.24 mg l?1 of this syndet. Reduction of haemoglobin, at RBC and WBC was observed at all the syndet levels and at both the exposure periods. Significant (P < 0.05) increases in hematocrit values were noted at 2.24 mg l?1 of SLS at both exposures.  相似文献   

3.
A laboratory study was conducted to compare the response of an activated sludge culture proliferating in an environment where the DO concentration was maintained between 8-9 mg l?1 to that of a culture in an environment where the DO concentration was 2 mg l?1 when both systems were subjected to identical loading fluctuations. It was observed that in the high DO system, filamentous microorganisms became the predominate form when the suspended solids concentration dropped below a value near 4000 mg l?1. However, no filamentous growth appeared in the alternate system until the suspended solids level dropped below 500 mg l?1. A model is developed which proposes to explain this observation.  相似文献   

4.
We investigated the coupling of abundance of bacteria, phytoplankton and ciliates with hydrocarbons in the surface water and sediments of five interconnected ponds in the arid Sfax solar salterns. This study aimed at determining the potential sources of hydrocarbons and the effects of salinity gradients on microorganism metabolism. Hydrocarbon analysis was performed by gas chromatography (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). The GC-FID allowed the detection of aliphatic hydrocarbons and n-alkanes ranging from n-C13 to n-C30. Total aliphatic hydrocarbon concentrations varied from 92.5 mg. l?1 in the first pond (having marine characteristics) to 661.1 mg. l?1 in the last pond (crystallizer) (316.8?±?120.1 mg. l?1) for water samples and from 26.7 to 127.8 μg. g?1 dry weight for sediment samples. The GC-MS enabled us to detect halogenated hydrocarbons (bromoalkanes and chloroalkanes) and n-alkenes. The distribution of n-alkanes indices coupled to several environmental factors suggests that a major fraction of hydrocarbons resulted from both prokaryotic (bacteria) and eukaryotic (protists) developments. A low hydrocarbon fraction might be petrogenic.  相似文献   

5.
Varying amounts of CaCl2 or MgCl2 were first equilibrated with a dilute suspension of H+-kaolin and then with spiked (high activity radioactive 64Cu) water. After filtration, through 0.45 μm Millipore membrane the amount of radioactivity on the filter and the filtrate was measured separately using a Gamma ray well counter. Adsorption of Cu (expressed as distribution coefficient ?K d ) was plotted against Ca or Mg concentration. K d values decreased sharply at Ca or Mg concentration from 0 to 10 mg l?1 and changed only slightly from 10 to 200 mg l?1. Increase in the concentration of Ca or Mg reduces the Cu binding capacity of the clay.  相似文献   

6.
Acute toxicity screening tests were conducted with water soluble fractions (WSFs) of a solvent refined coal (SRC-II) liquid from a pilot plant and three reference organisms: the cladoceran Daphnia magna, the fathead (FH) minnow Pimephales promelas, and larvae of the midge fly Chironomus tentans. Stock WSFs typically contained 900 to 1100 mg l?1 total carbon (TC) and 700 to 800 mg l?1 total dye complexable phenolics, with lower concentrations of aromatic and saturate hydrocarbons and N compounds. Under standard test conditions (temperature 20 °C, pH 7.3 to 8.2 and hardness 65 to 80 mg l?1 CaCO3), mean LC50 values in mg l? TC were 3.3 for daphnia, 11.l for FH minnow, and 13.7 for midge larvae. Acute toxicity was also examined under other water quality conditions (temperature 10 or 25 °C, pH 6.0 or 6.5, and hardness ? 180 to 220 mg 1?1 CaCO3). The coal liquid was less toxic to daphnids at 10 °C than at 20 or 25 °C, but response of other organisms at different temperatures varied. The pH of the liquid had little effect on toxicity values. All organisms were less susceptible in hard water. Chemical compositions of stock WSFs were similar, suggesting that temperature, pH, and hardness had little effect on solubility of major synfucl components. Dilution indexes for stock WSFs were higher than for petroleum oils, and reflect the greater solubility of chemicals from the liquified coal in freshwater.  相似文献   

7.
Degradation rates of the rooted hydrophyte Hydrilla sp. by a gram-negative non-motile rod shaped bacterium were determined. A first order model was conceived, which included the effects of nitrate nitrogen on the rate constants. The rate constants varied between 0.0239 day?1 and 0.0907 day?1 for nitrate nitrogen values of 0.48 mg l?1 to 5.38 mg l?1 A strong inverse relationship between degradation rate and nitrate levels within the range of 0.5 to 6.0 mg l?1 NO3-N was observed. The resultant model was able to predict plant degradation rates quite accurately as a function of nitrate levels.  相似文献   

8.
The effects of inoculating arbuscular mycorrhizal (AM) fungi on the growth, phosphorus (P) uptake, and yield of Welsh onion (Allium fistulosum L.) were examined under the non-sterile field condition. Welsh onion was inoculated with the AM fungus, Glomus R-10, and grown in a glasshouse for 58?days. Non-inoculated plants were grown as control. Inoculated and non-inoculated seedlings were transplanted to a field with four available soil P levels (300, 600, 1,000, and 1,500?mg P2O5?kg?1 soil) and grown for 109?days. AM fungus colonization, shoot P concentration, shoot dry weight, shoot length, and leaf sheath diameter were measured. Percentage AM fungus colonization of inoculated plants was 94% at transplant and ranged from 60% to 77% at harvest. Meanwhile, non-inoculated plants were colonized by indigenous AM fungi. Shoot length and leaf sheath diameter of inoculated plants were larger than those of non-inoculated plants grown in soil containing 300 and 600?mg P2O5?kg?1 soil. Shoot P content of inoculated plants was higher than that of non-inoculated plants grown in soil containing 300 and 600?mg P2O5?kg?1 soil. Yield (shoot dry weight) was higher for non-inoculated plants grown in soil containing 1,000 and 1,500?mg P2O5?kg?1 soil than for those grown in soil containing 300 and 600?mg?P2O5 kg?1 soil. Meanwhile, the yields of inoculated plants (200?g plant?1) grown in soils containing the four P levels were not significantly different. Yield of inoculated plants grown in soil containing 300?mg P2O5 kg?1 soil was similar to that of non-inoculated plants grown in soil containing 1,000?mg P2O5?kg?1 soil. The cost of AM fungal inoculum for inoculated plants was US$ 2,285?ha?1 and lower than the cost of superphosphate (US$ 5,659?ha?1) added to soil containing 1,000?mg P2O5 kg?1 soil for non-inoculated plants. These results indicate that the inoculation of AM fungi can achieve marketable yield of A. fistulosum under the field condition with reduced application of P fertilizer.  相似文献   

9.
Influences of phosphorus and nitrogen on uranium and arsenic accumulation in Lemna gibba L. were investigated in the laboratory hydroponic cultures and in the field pot experiments. The initial uranium and arsenic concentrations in solutions for the hydroponic cultures were 1000 μ g l?1 each, while in situ trials used tailing water containing 198.7 ± 20.0 μ g U l?1 and 75.0 ± 0.4 μ g As l?1 at a former uranium mine in eastern Germany. A test of three PO4 3? concentrations (0.01, 13.6 and 40.0 mg l?1) in the hydroponic cultures, highest uranium accumulated in L. gibba under the culture with highest PO4 3?. Significant differences in uranium accumulation were between 0.01 mg l?1 and 13.6 mg l?1 PO4 3? cultures only (ANOVA p = 0.05). In the field, addition of 40.0 mg l?1 PO4 3? increased the bioaccumulation of uranium significantly. Contrary, high PO4 3? concentrations suppressed the bioaccumulation of arsenic in both the laboratory and the field. The bioaccumulation of both uranium and arsenic increased slightly with the increase of NH4 + concentration. However, high NH4 + concentrations reduced the yield in the control experiments. The concentration of uranium rose temporarily to 856.0 ± 294.0 μ g l?1, while the concentration of arsenic sunk slightly and temporarily immediately after amending the tailing waters with 40 mg l?1 PO4 3?. The speciation of uranium in the tailing water was modelled with geochemical code PhreeqC, which predicted that uranyl carbonate species dominated before addition of phosphates, but after increasing the PO4 3? concentrations, uranyl phosphates species became dominant. Addition of NH4 + to the tailing water had negligible influence on free available uranium and arsenic concentrations. Thus, manipulations to enhance uranium and arsenic attenuation by L. gibba has limitation when the amendments interact with other elements including the contaminants in the milieu, and when the target contaminants have antagonistic behaviour in the tailing water.  相似文献   

10.
A linear gradient field exposure system was modified from one originally described by Shinn et al. (1977) and used to expose field grown soybeans (Glycine max cv Hark) to a concentration gradient of a mixture of two gaseous pollutants: SO2 and 03. Since this technique does not use enclosures, study plants experienced near ambient fluctuations in environmental conditions, including wind, and hence were exposed to widely fluctuating pollutant concentrations. Plants in the gradient system were exposed to both pollutants for 57 h on 12 days during the pod-filling period (31 August–17 September). Mean concentrations during the 57 h of exposure at the ‘high’ end of the gradient were 0.16 and 0.06 µl l?1 (PPM) SO2 and O3, respectively, with 10 h at greater than 0.25 and 0.10 µl?1 SO2 and O3, respectively. Total doses for these plants were estimated to be 9.0 and 3.5 µl?1 · h SO2 and O3, respectively. Comparison with plants exposed to ambient air indicated that exposure to SO2 and O3 reduced total yield per plant and dry mass per bean by as much as 36 and 15 %, respectively. Since concurrent exposure to a much higher dosage of SO2 alone (20.2 µl l?1 · h) was observed in a separate experiment to have no significant effect on yield, 03, although present at moderately low levels, was probably responsible (alone or synergistically with SO2) for the greatest reduction in seed size and yield.  相似文献   

11.
Four-year old Norway spruce (Picea abies (L.) Karst.) trees were pretreated at low and high water supply, and then placed into a growth chamber containing four compartments so that two levels of ozone exposure, 0.02 and 0.4 Μl l?1, could be replicated. They were exposed to ozone and drought stress for 59 days, and water use was determined by periodic weighing. Small effects of ozone treatment were detected on new shoot dry weight, and water use by trees receiving the high ozone treatment appeared higher. Both visual symptoms and ethylene biosynthesis showed that drought stress reduced damage to trees exposed to high ozone. Ethylene emission and 1-aminocyclopropane-1-carboxylic acid (ACC) levels increased after 18 days of exposure to 0.4 Μl l?1 ozone, while visual symptoms were seen at 30 days. After 59 days of exposure to the combined stresses, ethylene and ACC levels were lower, but showed an ozone x water interaction. Most ethylene and ACC were produced by wet trees at high ozone concentration, but dry trees also had high ethylene and ACC levels at low ozone. Levels of needle malonyl-ACC (MACC) were not significantly affected by treatment, and did not change with time, but root MACC levels, which were twice needle levels, were high in wet trees at high ozone concentration, but also high in dry trees at low ozone concentration. These results suggest that drought stress occurring during ozone exposure could be expected to reduce damage to young Norway spruce, and that this damage may be related to ethylene biosynthesis.  相似文献   

12.
Lead (Pb) is a ubiquitous environmental pollutant capable to induce various morphological, physiological, and biochemical functions in plants. Only few publications focus on the influence of Pb speciation both on its phytoavailability and phytotoxicity. Therefore, Pb toxicity (in terms of lipid peroxidation, hydrogen peroxide induction, and photosynthetic pigments contents) was studied in Vicia faba plants in relation with Pb uptake and speciation. V. faba seedlings were exposed to Pb supplied as Pb(NO3)2 or complexed by two fulvic acids (FAs), i.e. Suwannee River fulvic acid (SRFA) and Elliott Soil fulvic acid (ESFA), for 1, 12, and 24?h under controlled hydroponic conditions. For both FAs, Pb uptake and translocation by Vicia faba increased at low level (5?mg?l?1), whereas decreased at high level of application (25?mg?l?1). Despite the increased Pb uptake with FAs at low concentrations, there was no influence on the Pb toxicity to the plants. However, at high concentrations, FAs reduced Pb toxicity by reducing its uptake. These results highlighted the role of the dilution factor for FAs reactivity in relation with structure; SRFA was more effective than ESFA in reducing Pb uptake and alleviating Pb toxicity to V. faba due to comparatively strong binding affinity for the heavy metal.  相似文献   

13.
Acute exposure of the central stoneroller minnow to sublethal levels of phenol was found to decrease the ability of this species to tolerate hypoxic conditions as indicated by the dissolved oxygen (DO) concentration at which loss of equilibrium occurred. For fishes acclimated at 7.5 °C, loss of equilibrium occurred at progressively higher DO levels as the phenol exposure concentration was increased from 0 to 12 mg phenol L?1. Mean DO concentrations at which loss of equilibrium occurred ranged from 2.33 ± 0.10 mg O2 L?1. for the control group (0 mg phenol L?1. to 2.76 ± 0.14 mg O2 L?1. (at 12 mg phenol L?1. Loss of equilibrium also occurred at progressively higher DO levels in fish acclimated at 23 °C, but only after an initial decrease among the 6 mg phenol L?1. test fish in the loss of equilibrium DO concentration. At 23 °C, loss of equilibrium occurred at DO levels ranging from 1.3 ± 0.09 mg O2 L?1. (6 mg phenol L?1. to 2.33 ± 0.16 mg O2 L?1. (12 mg phenol L?1. These data indicate that acute exposures to sublethal levels of phenol can have significant effects on the ability of the stoneroller minnow to tolerate conditions of low DO, and the results agree with the previously reported relationship between phenol toxicity and DO levels.  相似文献   

14.
Soybean plants (Glycine max L. cv. Buchanan) were subjected to one of three levels of salinity preteatment (with electrical conductivities of 0.7, 4.4 and 6.5 dS m?1) and then exposed to one of three concentrations of SO2 (1, 145 and 300 bl l ?1 for 5 h d?1), or vice versa. Each stress episode lasted 3 weeks. Both salinity and SO2 deecreased leaf area, root and shoot dry weight and the fresh weight of root nodules. SO2 induced an increase in the shoot: root ratio and leaf chlorophyll concentrations. Low salinity pretreatment protected plant growth from SO2 injury, probably by decreasing SO2 uptake by increasing stomatal resistance. However, high salinity-treated plants, despite also showing stomatal closure, were severely injured by subsequent SO2 exposure. Prior exposure to SO2 caused plants to become more vulnerable to salt injury. Plants pretreated with high SO2 were killed after 12 days of high salt stress. These data suggest that the compensatory mechanisms and predisposition characteristics of salinity and SO2 largely depend upon the stress levels used.  相似文献   

15.
The effects of ozone (O3) and excess soil nitrogen (N), singly and in combination, on growth, needle gas exchange rates and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) contents of Pinus densiflora seedlings were investigated. One-year-old seedlings were grown in 1.5-L pots filled with brown forest soil with 3 levels of N supply (0, 100 or 300 mg N·L?1 fresh soil volume). The seedlings were exposed to charcoal-filtered air or 60±5 nL·L?1 O3 (8 hours a day) in naturally-lit phytotrons for 173 days from 22 May to 11 November. The exposure to O3 or high N supply to the soil caused a significant reduction in the dry weights of the seedlings. Although no significant interactive effects of O3 and excess soil N were detected on the dry weight growth of the seedlings, the whole-plant dry weight of the O3-exposed seedlings grown in the soil treated with 300 mg N·L?1 was greatly reduced compared with the control value. Ozone reduced net photosynthetic rate at 350 µmol·mol?1 CO2 (A 350 ), carboxylation efficiency (CE) of photosynthesis and Rubisco content without a significant change in the gaseous phase diffusive conductance to CO2 (gs) of the needles. The excess soil N reduced the A 350 , CE, gs and Rubisco content of the needles. These results suggest that the reduction in the dry weight growth of Pinus densiflora seedlings induced by the exposure to O3 and/or excess soil N was caused by reduction in the net photosynthetic rate mainly due to the decrease of Rubisco quantity in the chloroplasts.  相似文献   

16.
Acute toxicity of Pb to the water flea; (Daphnia sp) and Copepod, (Cyclop sp) both important component of zooplankton diet of fish was determined by static assay. A positive relationship between percentage mortality and exposure concentration was found in all tests. Mean 24-h LC50, 48-h LC50 and 96-h LC50 values were 2.51?±?0.0.04 mg l?1, 1.88?±?0.06 mg l?1 and 1.65?±?0.19 mg l?1 for Daphnia spp and 3.11?±?0.03 mg l?1, 2.97?±?0.05 mg l?1 and 2.61?±?0.09 mg l?1 for Cyclop spp, respectively. For all tested species did the LC50 values decrease with time; the decrease was more marked for Daphnia spp. Observed symptoms include spiral movement followed by change of body colour to white and rapid disintegration of the skin. The Daphnia spp. appear to be more sensitive to Pb poison than Cyclop spp. The results showed that concentrations of Lead (Pb) in excess of 0.19 mg l?1 and 0.30 mg l?1 can be potentially harmful to Daphnia magna and Cyclop spp respectively.  相似文献   

17.
Interactions between Zn and Cd on the accumulation of these metals in coontail, Ceratophyllum demersum were studied at different metal concentrations. Plants were grown in nutrient solution containing Cd (0.05–0.25 mg l?1) and Zn (0.5–5 mgl?1). High concentrations of Zn caused a significant decrease in Cd accumulation. In general, adding Cd solution decreased Zn accumulation in C. demersum except at the lowest concentration of Zn in which the Zn accumulation was similar to that without Cd. C. demersum could accumulate high concentrations of both Cd and Zn. The influence of humic acid (HA) on Cd and Zn accumulation was also studied. HA had a significant effect on Zn accumulation in plants. 2 mg l?1 of HA reduced Zn accumulation at 1 mg l?1 level (from 2,167 to 803 mg kg?1). Cd uptake by plant tissue, toxicity symptoms and accumulation at 0.25 and 0.5 mg l?1, were reduced (from 515 to 154 mg kg?1 and from 816 to 305 mg kg?1, respectively) by addition of 2 mg l?1 of HA. Cd uptake reached a maximum on day 9 of treatment, while that of Zn was observed on day 15. Long-term accumulation study revealed that HA reduced toxicity and accumulation of heavy metals.  相似文献   

18.
Effluent from the septic tanks of five households was sampled daily for 15 days. Temperature, redox potential, conductivity and biochemical oxygen demand (BOD5) were measured and samples were analyzed for N, P, Ca, Mg, Na, K, Zu, Zn, Cd, Cr, Pb, Mg, and linear alkylate sulphonate (LAS). Samples from the five households differed in the values obtained but the differences were small. Little daily variation occurred in the effluent from any one household. The effluent was in a reduced and anaerobic condition with almost all the N and P occurring in the inorganic form in solution. The effluent concentration N was about 100 mg l?1 and P concentration about 15 mg l?1. The mean annual N and P loading in the effluent over the five households was 3.8 kg N/head yr and 0.6 kg P/head · yr. Copper and Zn were the only trace metals of any significance and their concentrations were less than in tap water. The chemical composition of the effluent was very similar to that found in New Zealand, Canada, and U.S.A.  相似文献   

19.
The 48 and 96-hr LC50 values of Pb (Pb(NO3)2) with O. niloticus were 3.34 and 2.15 mg L?1, respectively, compared to 1.91 and 1.72 mg L?1, respectively, for C. lazera. C. tentans larvae and Benacus sp. demonstrated 48-hr LC 50 of 2.68 and 1.89 mg l?1 respectively. The 96-hr LC50 value was 1.77 mg L?1 for Chironomus and 1.36 mg L?1 for Benacus. Clarias appeared to be the most susceptible of the four to Pb poisoning; Chironomus being the least susceptible. Uptake pattern of Pb by fingerlings of O. niloticus and C. lazera exposed to 0.33 and 0.27 mg L?1 Pb, respectively, and the clearance of accumulated Pb were curvilinear. There was an initial ‘fast’ phase of accumulation occurring during the first 96 hr, followed by a slower phase over the remaining 240 hr. Mean Pb concentrations in gills, intestine, liver, muscle, bone, skin and whole body of O. niloticus were 33.30, 22.2, 5.3, 2.8, 1.8 and 14.9 μg g?1, respectively, compared to 28.7, 6.5, 11.5, 2.5, 5.6, 5.9 and 6.8 µg g?1 respectively in C. lazera. The half life of Pb in Oreochromis was 20 hr compared to 43 hr in C. lazera. Bioconcentration factors in Oreochromis and Clarias were 78.3 and 33.8, respectively. The data suggest that O. niloticus accumulates and eliminates Pb faster than C. lazera.  相似文献   

20.
The early life stages of smallmouth bass (Micropterus dolomieui) were exposed to Pb in acute (96 hr) and sub-chronic (90 day) bioassays (water hardness = 152 mg L?1 as CaCO3). After 96-hr static exposures at nominal Pb concentrations up to 15.9 mg L?1, eggs and sac fry showed no increased mortality over that in controls. Swim-up fry (96-hr LC50 = 2.8 mg Pb L?1) were more sensitive to Pb exposure than were fingerlings (96-hr LC50 of 29.0 mg Pb L?1 ). The relation between dissolved Pb and mortality was non-significant for either swim-up fry or fingerlings. Fingerlings were exposed to Pb concentrations as high as 405 μg L?1 for 90 day to evaluate effects on substrate selection, locomotor activity, hematology, and weight. Dark or light substrate selection (cover-seeking) and locomotor activity, weight and hemoglobin concentration in the blood were not significantly altered by any treatment. Hematocrit and leucocrit varied significantly but not in relation to Pb levels. Sub-chronic Pb exposure did not appear to represent a threat to smallmouth bass in waters of medium hardness and above-neutral pH (7.1 to 7.9).  相似文献   

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