Subacute stress induced by sodium lauryl sulphate (SLS) on certain haematological parameters in Saccobranchus fossilis

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.     

Seed priming to mitigate the impact of elevated carbon dioxide associated temperature stress on germination in rice (Oryza sativa L.)

ABSTRACT

Climate change has a negative impact on crop production by inducing several stresses throughout plant growth. As the germination is one of the critical stages, this study was to assess the impact of elevated carbon dioxide (eCO₂) and associated temperature stress on germination of rice. The study was conducted using the rice genotype CO 51 in artificially induced eCO₂ condition using open-top chamber (OTC). The efficiency of seed priming treatment with salicylic acid (SA), citric acid (CA), ascorbic acid (AsA) and distilled water (hydropriming) to alleviate stress due to eCO₂ and temperature were also studied. SA 25 mg l^?1 and AsA 100 mg l^?1 enhanced germination, other seed quality parameters along with α- amylase activity. Also, the activity of antioxidant enzymes like catalase, peroxidase and superoxide dismutase was increased. These parameters positively affected the germination and growth by mitigating the effect of oxidative stress induced under eCO₂ conditions. So, SA, CA and AsA can be effectively used for maintaining seed quality parameters and seedling growth during the stresses.     

Influences of Cadmium and Zinc Interaction and Humic Acid on Metal Accumulation in Ceratophyllum Demersum

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.     

Comparison of Low-Molecular-Weight Organic Acids and Ethylenediaminetetraacetic Acid to Enhance Phytoextraction of Heavy Metals by Maize

We compared acetic, ascorbic, and oxalic acids with ethylenediaminetetraacetic acid (EDTA) to enhance phytoextraction of nickel (Ni), manganese (Mn), zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb) by maize. Except ascorbic acid, acids significantly (P < 0.05) decreased shoot dry weight with maximum (5.60 g pot^?1) recorded with ascorbic acid and minimum with oxalic acid (4.06 g pot^?1). Maximum ammonium bicarbonate–diethylenetriaminepenta acetic acid (AB-DTPA)–extractable nickel (19.94 mg kg^?1) was recorded with EDTA and it was minimum (10.57 mg kg^?1) with oxalic acid. The EDTA significantly (P < 0.05) increased AB-DTPA-extractable lead while other acids decreased it. Except acetic acid, other acids significantly (P < 0.05) increased Ni and Zn concentration in shoots with maximum Ni (9.22 mg kg^?1) and Zn (37.40 mg kg^?1) with EDTA.     

Aluminum toxicity to fish in acidic waters

An important consequence of acidification is the mobilization of Al from the edaphic to the aquatic environment. Elevated Al levels in acidic waters may be toxic to fish. Eggs, larvae, and postlarvae of white suckers (Catostomus commersoni) and brook trout (Salvelinus fontinalis) were exposed in laboratory bioassays to pH levels 4.2 to 5.6 and inorganic Al concentrations of 0 to 0.5 mg l^?1. Aluminum toxicity varied with both pH and life history stage. At low pH levels (4.2 to 4.8), the presence of Al (up 0.2 mg l^?1 for white suckers; 0.5 mg l^?1 for brook trout) was beneficial to egg survival through the eyed stage. In contrast, Al concentrations of 0.1 mg l^?1 (for white suckers) or 0.2 mg l^?1 (for brook trout) and greater resulted in measurable reductions in survival and growth of larvae and postlarvae at all pH levels (4.2 to 5.6). Aluminum was most toxic in over-saturated solutions at pH levels 5.2 to 5.4. The simultaneous increase in Al concentration with elevated acidity must be considered to accurately assess the potential effect of acidification of surface waters on survival of fish populations.     

Toxicity of Lead to Freshwater Invertebrates (Water fleas; Daphnia magna and Cyclop sp) in Fish Ponds in a Tropical Floodplain

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.     

Chronic effects of reduced dissolved oxygen on Daphnia magna

Daphnia magna, initially exposed when less than 48 h old, were maintained at reduced dissolved oxygen (DO) concentrations for 26 days. Exposure was accomplished in a continuous flow recirculating water system. Number of days to first brood, number of young in the first brood, total number of young produced, and dry weight were parameters measured. Statistical analyses show the Daphnia exposed to the lowest DO concentration tested (1.8 mg l^?1) had significantly reduced responses for all parameters measured. In addition, the organisms exposed to 2.7 mg l^?1 O₂ gained less weight than did the controls.     

Effect of Organic Ligands on Copper(II) Removal from Metal Plating Wastewater by Orange Peel-based Biosorbents

A neutrophilic, autotrophic bacterium that couples iron oxidation to nitrate reduction (iron-oxidizing bacteria [IOB]) under anoxic conditions was isolated from a working bioremediation site in Trail, British Columbia. The site was designed and developed primarily to treat high concentrations of Zn and As that originate from capped industrial landfill sites. The system consisted of two upflow biochemical reactor cells (BCR) followed by three vegetated wetland polishing cells with sub-surface flow and a holding pond. During a 5-year period (2003–2007), the system treated more than 19,100 m³ of contaminated water, removing and sequestering more than 10,700 kg of As, Zn and sulfate at average input water concentrations of: As, 58.6 mg?l^?1 (±39.9 mg?l^?1); Zn, 51.9 mg?l^?1 (±35.4 mg?l^?1) and SO₄ ^2?, 781.5 mg?l^?1 (±287.8 mg?l^?1). The bacterium was isolated in order to better understand the mechanisms underlying the consistent As removal that took place in the system. Analysis using Basic Local Alignment Search Tool (BLAST) database showed that the closest homologies are to Candidatus accumulibacterphosphatis (95 % homology), Dechloromonas aromatica (94 %), and Sideroxydans lithotrophicus ES-1 (92 %) Within the BCR cells, the IOB oxidized Fe²⁺ generated by iron-reducing bacteria (IRB); the source of the iron was most likely biosolids and coatings of iron oxide on locally available sand used in the matrix. We have provisionally designated the novel bacterium as TR1.     

Impact of Environmental Conditions on the Phytoplankton Structure in Mediterranean Sea Lagoon, Lake Burullus, Egypt

Lake Burullus is one of the northern Delta lakes, connected with the Mediterranean Sea through El-Boughaz opening. The main objective of the present work is to study the physical and chemical properties of the lake and its relation with the phytoplankton communities, chlorophyll-a as well as diversity and Eutrophication index. The studies revealed that, the pH values lie in alkaline side, with wide range of fluctuation (7.15–8.5), the total suspended matter was relatively high (18.2–149 mg l^?1), high values of dissolved oxygen (5.17–11.29 ml l^?1) and high concentration of nutrient salts, (nitrate ranged between (3.4–44.7 μmole l^?1), nitrite (0.42–15.95 μmole l^?1), ammonia (1.46–50.60 μmole l^?1), phosphate (0.63–14.83 μmole l^?1), and silicate (6.54 to 119.3 μmole l^?1). Chlorophyll-a concentration showed a wide range of fluctuation (13.8–127.4 μg/l) and the highest value were recorded at the western region of the lake. Phytoplankton counts showed a pronounced increase (1.9 × 10⁶ units l^?1) as compared with previous studies, a total of 170 species were identified represented mainly by Bacillariophyceae (44.8% to the total community) comprising 68 species, Chlorophyceae (39.99%) 54 species, followed by Cyanobacteria (9.52%) 26 species, Euglenophyceae (5.63%) 15 species. Phytoplankton standing crop attained the highest counts at the western sector particularly at station X during spring and summer (6.7×106 and 4.1×10⁶ units l^?1 respectively) due to the dominance of Bacillariohycean species Stephanodiscus phytoplankton diversity was high and showed widely range (1.47–3.66 nats). A series of stepwise regression equations describing the dependence of phytoplankton standing crop, its main groups and diversity index on the changes of the most biotic prevailing conditions were given and discussed. In general, the results showed that the Lake is considered as a eutrophic area. This phenomenon observed in the body of the lake water that receives large influxes of nutrients, which reflects high phytoplankton counts, diversity index and Chlorophyll-a     

Detection of Water and Sediments Pollution of An Arid Saltern (Sfax, Tunisia) by Coupling the Distribution of Microorganisms With Hydrocarbons

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.     

Resource manipulation in uranium and arsenic attenuation by Lemna gibba L. (duckweed) in tailing water of a former uranium mine

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.     

Influence of phosphorus limitations on the growth,nutrient partitioning and physiology of mahogany (Swietenia macrophylla King) seedlings

The effects of four rates of phosphorus (P) fertilization (0, 0.56, 5.6 and 56.0 mg l^?1) in soilless medium on the growth and physiology of mahogany seedlings were examined. The greatest response occurred at the 56 mg l^?1 rate, with relatively small differences between other treatments. Biometric parameters increased at the 56 mg l^?1 compared to 0 mg l^?1 rate except root dry mass. Both the concentration and the total content of P and Kjeldahl nitrogen (N) increased in leaves, stems and roots with P application rate. Foliar concentrations of potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn) and sulfur (S) declined, and boron (B) and copper (Cu) increased with P limitations; zinc (Zn) and iron (Fe) were unaffected. Physiological adaptations of mahogany to P limitations include the preferential allocation of carbon (C) to plant roots, and increases in P utilization efficiency, P acquisition efficiency and the concentration of organic acids in xylem fluid. Root phosphatase activity was not influenced by P fertilization.     

Study of Heavy Metal Accumulation and Residual Toxicity in Soil Saturated with Phosphate Processing Wastewater

The effects of phosphate processing wastewater (PPWW) on heavy metal accumulation in a Mediterranean soil (Tunisia, North Africa) were investigated. Moreover, the residual toxicities of PPWW-irrigated soils extracts were assessed. Results showed that heavy metal accumulation was significantly higher in PPWW-irrigated soil extracts than in control soil. The heavy metal accumulation increased over time in treated soil samples and their average values followed the following order: Iron (Fe 252.72 mg l^?1) > Zinc (Zn 152.95 mg l^?1) > Lead (Pb 128.35 mg l^?1) > Copper (Cu 116.82 mg l^?1) > Cadmium (Cd 58.03 mg l^?1). The residual microtoxicity and phytotoxicity of the various treated soil samples extracts were evaluated by monitoring the bioluminescence inhibition (BI %) of Vibrio ficheri and the measurement of the germination indexes (GI %) of Lepidium sativum and Medicago sativa seeds. The results showed an important increase of residual toxicities of PPWW-treated soil extracts over time.     

Effect of substrate,nutrition and growth regulator on productivity and mineral composition of leaf and pseudobulb of Cymbidium hybrid “Baltic Glacier Mint Ice”

The study evaluates the effect of various potting media, nutrition, and growth regulators on production and nutrient composition of leaf and pseudobulb of Cymbidium hybrid “Baltic Glacier Mint Ice” grown in greenhouses. The results confirmed a positive influence of growth and nutrition on flower yield of Cymbidium, with shredded tree bark+ coconut husk + brick bits giving the best flowering. A nitrogen, phosphorus and potassium (NPK) dose of 200:200:200 mg l^?1 with benzyl adenine (BA) and gibberellic acid (GA₃) at 50 mg l^?1 was found best for growth while an NPK dose of 200:100:100 mg l^?1 with BA and GA₃ at 50 mg l^?1 was suitable flower production of Cymbidium hybrid. Application of an NPK dose of 300:200:300 mg l^?1 with BA and GA₃ at 500 mg l^?1 was found to be best for enhancing flowering frequency. Plants of the Cymbidium hybrid with the best flowering characteristics mostly contained significantly higher concentrations of nitrogen (N), phosphorus (P) and potassium (K) in leaves and pseudobulbs (which acts as reservoir of nutrients).     

Plant growth inhibition by the water extract of a crude oil

The water extract of a light Nigerian crude oil had pronounced effects on the growth, metabolism and development of radish (Raphanus sativus) plants. In addition to hydrocarbons (ca. 7 mg l^?1) the extract contained phenols (ca. 0.6 mg l^?1), carbonyl compounds, and carboxylic acids. Although seed germination was virtually unaffected, the growth of both above- and below-ground parts was significantly inhibited when the plants were watered with the extract rather than with well water. In addition, the onset of flowering was significantly delayed in the extract-treated plants, and the number of plants which ever flowered was reduced. Significantly increased respiration was observed in leaf tissue of the extract-treated plants, but photosynthetic carbon fixation was not significantly affected. The extract appeared to elicit effects similar to those caused by other forms of environmental stress, such as infections.     

Removal of Pentachlorophenol by Adsorption on Magnetite-immobilized Chitin

The application of magnetite-immobilized chitin in pentachlorophenol (PCP) removal was demonstrated in this study. The physicochemical parameters for immobilization of chitin by magnetite, and for PCP adsorption using magnetite-immobilized chitin were optimized. For chitin immobilization, the optimized conditions were: magnetite to chitin (m:c) ratio at 1:2, initial pH 6, 25°C, 200 rpm and 60 min in batch system. The immobilization efficiency (IE) was 99.4% and immobilization capacity (IC) was 2.0 mg chitin mg^?1 magnetite. High initial pH (pH?>?11) and temperature (>30°C) lowered the IE and IC. For PCP (10 mg l^?1) adsorption, the optimized conditions were: 1,500 mg l^?1 immobilized chitin, initial pH 6, 25°C, 200 rpm and 60 min in batch system. The removal efficiency (RE) was 57.9% and removal capacity (RC) was 5.4 mg g^?1. The adsorption ability of immobilized chitin decreased with pH and temperature increased. However, increasing the amount of immobilized chitin (24,000 mg l^?1) can increase the RE up to 92%. Both chitin immobilization and PCP adsorption exhibited Langmuir and Freundlich adsorption isotherms. Results in this study indicated that magnetite-immobilized chitin was a cost-effective and environmental friendly adsorbent to remove environmental pollutants such as PCP.     

The kinetics of bacterial degradation of the aquatic weed ‘Hydrilla’ sp.

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.     

Vermicomposting leachate as liquid fertilizer for the cultivation of sugarcane (Saccharum sp.)

In vermicomposting, the main product is the worm casts, but a leachate is generated that contains large amounts of plant nutrients. This leachate is normally diluted to avoid plant damage. We investigated how dilution of vermicompost leachate combined with different concentrations of nitrogen (N) - phosphorus (P) - potassium (K) triple 17 fertilizer, and polyoxyethylene tridecyl alcohol as dispersant and polyethylene nonylphenol as adherent to increase efficiency of fertilizer uptake, affected sugarcane plant development. The vermicomposting leachate with pH 7.8 and electrolytic conductivity 2.6 dS m^?1, contained 834 mg potassium (K) l^?1, 247 mg nitrate (NO₃^?) l^?1 and 168 mg phosphate (PO₄^3?) l^?1, was free of pathogens and resulted in a 65% germination index. Vermicompost leachate did not inhibit sugarcane growth and mixed with 170 g l^?1 NPK triple 17 fertilizer resulted in the best plant development. No dispersant or adherent was required to improve plant height and stem development.     

Effect of fulvic acids on lead-induced oxidative stress to metal sensitive Vicia faba L. plant

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.     

Effect of cations on copper adsorption by kaolin

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.