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PubMed2002

Filamentous fungi in Indah Water Konsortium (IWK) sewage treatment plant for biological treatment of domestic wastewater sludge.

A study was carried out to isolate and identify filamentous fungi for the treatment of domestic wastewater sludge by enhancing biodegradability, settleability and dewaterability of treated sludge using liquid state bioconversion process. A total of 70 strains of filamentous fungi were isolated from three different sources (wastewater, sewage sludge and leachate) of IWK's (Indah Water Konsortium) sewage treatment plant, Malaysia. The isolated strains were purified by conventional techniques and identified by microscopic examination. The strains isolated belonged to the genera of Penicillium, Aspergillus, Trichoderma, Spicaria and Hyaloflorae The distribution of observed isolated fungi were 41% in sewage sludge followed by 39% in wastewater and 20% in leachate. The predominant fungus was Penicillium (39 strains). The second and third most common isolates were Aspergillus (14 strains) and Trichoderma (12 strains). The other isolates were Spicaria (3 strains) and Hyaloflorae (2 strains). Three strains (WWZP1003, LZP3001, LZP3005) of Penicillium (P. corylophilum, P. waksmanii, and P. citrinum respectively), 2 strains (WWZA1006 and SS2017) of Aspergillus (A. terrues and A. flavus respectively) and one strain (SSZT2008) of Trichoderma (T. harzianum) were tentatively identified up to species level and finally verified by CABI Bioscience Identification Services, UK.

Biodegradation, Environmental↗
PubMed2002

Metal leachability from sewage sludge-amended Thai soils.

Determining mobility and availability of metals in sewage sludge amended soil is an environmental concern. Potential leachability and bioavailability of metals following sludge applied to agricultural soil was evaluated. Geochemical forms of metal occurring in sludge-amended soil were subjected to fractionation for understanding heavy metal transformation and remobilization in sludge-amended soil. Metal leachability was determined using reconstructed soil profiles where dewatered sewage sludge was incorporated into the surface 0-10 cm of soil. Two-sludge application rates; 150 and 300 kgN/ha, equivalent to sludge at 4 and 8 ton/ha, were applied to soil columns representing typical agricultural clay soils of Thailand (Rangsit acid sulfate soil). The soil columns were leached with 321 equivalent to 600 mm of surface water using different leachants (distilled water pH 6, distilled water adjusted to pH 3 and rainwater pH 5). Among metals measurement, results showed Mn leachability from sludge-amended Rangsit soil were high at both sludge application rates (18-29% of total Mn applied). The leachability of other metals was less than 2.5 and 7.2% following application of 150 and 300 kgN/ha of sludge, respectively. Results from the experiments indicated that the leachant at pH 3 had the most effect on potential leachability of Cu, Zn, Cd, and Ni, except Fe and Mn, at low sludge application rate. Whereas, only the leachability of two metals was influenced by the lowest pH (pH 3) when sludge applied was increased. Besides pH of leachant, it appeared that leachability of elements from the soil column depended on rate of sludge applied, the particular metal, and metal form or fraction. The soil studied had organic matter, CEC, pH, clay content, etc., that resulted in high buffering capacity, which favors metal retention. Less than 0.5 and 1.8% of the added Cu and Zn applied at the 150 and 300 kgN/ha application rates, respectively, were detected in the leachate. Approximately 100% of the added Cu and Zn in the sludge remained in the surface 10 cm at each sludge application rate. Sequential extraction of sludge-amended soil following leaching (at the high sludge application rate) revealed that most of the Cu remained in the surface sludge-amended soil layer (0-2 cm depth) in the form of organic and residual Cu fractions that are not easily mobilized. An exchangeable fraction of Zn increased, approximately representing 60% total Zn applied in sludge-soil layer as compared with its native soil Zn fractions. These results demonstrate that Zn availability in the soil would increase as a result of sludge application. However, the total Zn in the leachate is safe for agricultural use, because it represents an amount of less than 2% of total Zn applied.

Agriculture↗
PubMed2002

Feasibility study on the operation of UASB reactor treating acidified food waste. Upflow anaerobic sludge blanket.

A mesophilic upflow anaerobic sludge blanket (UASB) reactor seeded with granules adapted to VFA wastewater was operated as the methanogenic phase of a two-phase anaerobic batch process for food waste digestion. A semi-liquid recycle reactor filled with food waste was used as the acidification reactor and first recirculated for 8 days in the pre-acidification stage, resulting in 14,500 mg/L of total VFA and 15,800 mg/L of COD in the leachate. During the subsequent 8 days of two-phase operation, the leachate was circulated to the UASB reactor. In methanogenic phase, biogas with methane content of 68% on average was generated, and COD and total VFA removals were 74-93% and 77-99%, respectively. At the end of two-phase process, 65% of volatile solids removal and 0.30 L/gVS of methane yield were obtained. The results of this laboratory-scale study show that an UASB system can be used as the methanogenic phase in a two-phase anaerobic batch process, and is effective for conversion of the acidified food waste.

Acids↗
PubMed2004

Adsorption, desorption, and mobility of permethrin in Malaysian soils.

The adsorption, desorption, and mobility of permethrin in six tropical soils was determined under laboratory and greenhouse conditions. The six soils were selected from vegetable growing areas in Malaysia. Soil organic matter (OM) was positively correlated (r2 = 0.97) with the adsorption of permethrin. The two soils, namely, Teringkap 1 and Lating series with the highest OM (3.2 and 2.9%) released 32.5 and 30.8% of the adsorbed permethrin after four consecutive repetitions of the desorption process, respectively, compared to approximately 75.4% of the Gunung Berinchang soil with the lowest OM (1.0%) under the same conditions. The mobility of permethrin down the soil column was inversely correlated to the organic matter content of the soil. Permethrin residue penetrated only to the 10-15 cm zone in the Teringkap 1 soil with 3.2% OM but penetrated to a depth of more than 20 cm in the other soils. The Berinchang series soil with the lowest OM (1.0%) yielded leachate with 14.8% permethrin, the highest level in leachates from all the soils tested. Therefore, the possibility for permethrin to contaminate underground water may be greater in the presence of low organic matter content, which subsequently allows a higher percentage of permethrin to move downwards through the soil column.

Adsorption↗
PubMedDate not supplied

Analysis of the neurotoxic plasticizer n-butylbenzenesulfonamide by gas chromatography combined with accurate mass selected ion monitoring.

The plasticizer, n-butylbenzenesulfonamide (NBBS), is reported to be neurotoxic when inoculated intracisternally or intraperitoneally into rabbits. Because NBBS is commonly used in the production of polyamide (nylon) plastics and is soluble in water, the disposal of NBBS-containing plastics in landfill sites could result in NBBS appearing in the leachate. Further, NBBS could also be leached from packaging into their contents. To allow us to examine the risks posed by NBBS in the environment, we have developed a quantitative assay for this compound. The assay employs a one-step extraction into dichloromethane followed by gas chromatography with accurate mass selected ion recording. The assay incorporates [13C6]NBBS as an internal standard to allow precise quantitation, and four separate ion chromatograms are recorded. NBBS was found in some Australian domestic solidwaste landfill leachate (from less than 0.3 to 94.6 ng/mL), but ground water in the vicinity of a landfill had only trace quantities of NBBS. NBBS was also quantitated in some bottled and cask wines, and levels varied from not detected to 2.17 ng/mL (n = 14). Additional studies are required to assess the public health risks associated with the use of NBBS as a plasticizer.

Gas Chromatography-Mass Spectrometry↗
PubMed2000

Solute balance of a maize (Zea mays L.) source leaf as affected by salt treatment with special emphasis on phloem retranslocation and ion leaching.

Strategies for avoiding ion accumulation in leaves of plants grown at high concentration of NaCl (100 mol m(-3)) in the rooting media, i.e. retranslocation via the phloem and leaching from the leaf surface, were quantified for fully developed leaves of maize plants cultivated hydroponically with or without salt, and with or without sprinkling (to induce leaching). Phloem sap, apoplastic fluid, xylem sap, solutes from leaf and root tissues, and the leachate were analysed for carbohydrates, amino acids, malate, and inorganic ions. In spite of a reduced growth rate Na(+) and Cl(-) concentrations in the leaf apoplast remained relatively low (about 4-5 mol m(-3)) under salt treatment. Concentrations of Na(+) and Cl(-) in the phloem sap of salt-treated maize did not exceed 12 and 32 mol m(-3), respectively, and thus remained lower than described for other species. However, phloem transport rates of these ions were higher than reported for other species. The relatively high translocation rate of ions found in maize may be due to the higher carbon translocation rate observed for C(4) plants as opposed to C(3) plants. Approximately 13-36% of the Na(+) and Cl(-) imported into the leaves through the xylem were exported by the phloem. It is concluded that phloem transport plays an important role in controlling the NaCl content of the leaf in maize. Surprisingly, leaching by artificial rain did not affect plant growth. Ion concentrations in the leachate were lower than reported for other plants but increased with NaCl treatment.

Biological Transport↗
PubMed1983

Anaerobiosis and Release from Dormancy in Apple Embryos: Leaching of (+/-) [C]Abscisic Acid and its Metabolites under Aerobic and Anaerobic Conditions.

An anaerobic treatment released Pyrus malus L. cv Golden Delicious embryos from their primary dormancy. It also suppressed the inhibitory effect induced by exogenous abscisic acid (ABA) on after-ripened embryos. For the study of ABA metabolism, a two-step culture method was developed. Embryos in primary dormancy were cultivated aerobically in the presence of [(14)C]ABA (first culture). Some were directly analyzed to evaluate metabolism of absorbed ABA. The remaining embryos were cultivated on moist cotton without ABA, either in aerobic or anaerobic conditions (second culture). The amounts of ABA and its metabolites were measured both in the embryos and the water-leachates. After the second culture, the embryos showed a spectacular decrease in ABA content, with no difference between anaerobic and aerobic cultures. The amount of ABA glucose ester increased slightly in aerobiosis but diminished markedly in anaerobiosis. Radioactivity of the butanol fraction, which corresponded to polar conjugates, decreased considerably in anaerobiosis, whereas it increased in aerobiosis.Analysis of the water-leachates indicated that, compared to aerobic conditions, anaerobiosis increased total leaching of radioactive materials (x 4.2) as well as leaching of ABA (x 1.4). In addition, anaerobiosis induced leaching of conjugates, such as ABA glucose ester and butanol-soluble metabolites. We concluded that the anaerobic treatment affects mainly membrane permeability.

Journal Article↗
PubMed1988

Abscisic Acid Is an Endogenous Inhibitor in the Regulation of Mannanase Production by Isolated Lettuce (Lactuca sativa cv Grand Rapids) Endosperms.

The production of mannanase, a cell-wall-degrading carbohydrase, can be manipulated in isolated lettuce (Lactuca sativa cv Grand Rapids) endosperms by changes in the volume of buffer in which they are incubated. The enzyme is produced when endosperms are incubated in a large volume, but not when incubated in a small volume, which is suggestive that an endogenous, diffusible inhibitor of mannanase production is being lost from the endosperms in a large volume (JD Bewley, P Halmer 1980/1981 Israel J Bot 29: 118-132). We have investigated the possibility that the phytohormone abscisic acid (ABA) is involved in this regulation of mannanase production in isolated lettuce endosperms. We find several correlations between the presence of the endogenous inhibitor and of ABA, i.e. (a) a ;leachate' prepared from isolated lettuce endosperms induces synthesis of ABA-specific proteins in barley aleurone layers, indicating that incubation of endosperms in a large volume results in the diffusion of ABA therefrom into the surrounding medium; (b) fractionation of the components of a leachate by either polyvinylpyrrolidone-chromatography of C(18) reversed-phase high performance liquid chromatography fails to separate the endogenous inhibitor from authentic ABA; and (c) changes in the incubation volume of endosperms result in changes in the amount of extractable ABA in the endosperms, as detected by ELISA. These results are consistent with a role for endogenous ABA in the regulation of mannanase production in isolated lettuce endosperms.

Journal Article↗
PubMed2005

Growth and survival of bacteria implicated in sudden infant death syndrome on cot mattress materials.

AIMS: To compare growth and survival of selected bacteria implicated in sudden infant death syndrome (SIDS) on cot mattress polyurethane (PU) inner-foams and on different types of cot mattress cover materials. METHODS AND RESULTS: Escherichia coli, Staphylococcus aureus or Streptococcus pyogenes were inoculated onto swatches of new-unused cot mattress PU inner-foam and onto three types of cot mattress covers (polyvinyl chloride, cotton and polyester). The influence of inoculation cell density, relative humidity (RH) and temperature of incubation on survival was assessed by recovery of cells in 0.85% NaCl, with viable cell enumeration by plate counting on selective and differential media. Utilization of carbon and nitrogen sources within cot mattress PU was assessed by following growth on aqueous leachate from PU, and by colorimetric determination of aromatic amines. Good survival capability (>206 d) was shown by all three test species on PU inner-foam and on polyester mattress cover at high RH (75%), but only by Staph. aureus on PU at low RH (25%). Aqueous soluble material from PU foam supports bacterial growth; removal of aromatic amines from aqueous leachate from PU accompanies growth of Staph. aureus. CONCLUSIONS: Staphylococcus aureus has good survival capability on cot mattress PU foam, even at low RH. Soluble material within PU can serve as carbon and nitrogen sources for bacterial growth. SIGNIFICANCE AND IMPACT OF THE STUDY: Prolonged survival of Staph. aureus on PU at low RH could explain, in the context of the common bacterial toxins hypothesis, an increased risk of SIDS associated with used infant mattresses.

Amino Acids, Aromatic↗
PubMed2006

Allelochemical stress causes inhibition of growth and oxidative damage in Lycopersicon esculentum Mill.

The aim of this study was to analyse the effect of allelochemical stress on Lycopersicon esculentum growth. Our results showed that allelochemical stress caused by Sicyos deppei aqueous leachate inhibited root growth but not germination, and produced an imbalance in the oxidative status of cells in both ungerminated seeds and in primary roots. We observed changes in activity of catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione reductase (GR) and the plasma membrane NADPH oxidase, as well as in the levels of H(2)O(2) and O(2) (*-) in seeds at 12 and 24 h, and in primary roots at 48 and 72 h of treatment, which could account for the oxidative imbalance. There were changes in levels of expression of the mentioned enzymes, but without a correlation with their respective activities. Higher levels of membrane lipid peroxidation were observed in primary roots at 48 and 72 h of treatment. No effect on the expression of metacaspase and the PR1 was observed as indicators of cell death or induction of plant defence. This paper contributes to the understanding of plant-plant interactions through the phytotoxic allelochemicals released in an aqueous leachate of the weed S. deppei, which cause a negative effect on other plants.

Ascorbate Peroxidases↗
PubMed2005

Soil macropores and compaction control the leaching potential of Escherichia coli O157:H7.

The influence of soil structure in controlling leaching of Escherichia coli O157:H7 through soil was investigated under controlled conditions using both intact and repacked soil cores. Leaching rates of E. coli O157:H7 decreased with increasing dry bulk density and were significantly increased by the presence of earthworm (Lumbricus terrestris) burrows in repacked cores. For intact cores, the percentage of E. coli O157:H7 that leached through replicate cores within 72 h varied from 0.01% to 24%. In contrast, the dry bulk densities of intact cores varied only slightly and were not significantly correlated with leaching. Differences in the numbers of E. coli O157:H7 cells in the leachates were not related to variability in the flow volumes, which were relatively constant as a result of the experimental design, but were strongly correlated with the variations in concentrations of E. coli O157:H7 in the leachates. Relatively small variations in the internal structure of soil cores can therefore significantly affect the pathway that cells can take through soil. Factors such as compaction and the occurrence of pores providing preferential flow are prime determinants in the degree of leaching of E. coli O157:H7 through soil.

Colony Count, Microbial↗
PubMed1996

Volatiles from the 1994 Eruptions of Rabaul: Understanding Large Caldera Systems

The 1994 eruption of Rabaul, in Papua New Guinea, involved a small plinian eruption at Vulcan and a vulcanian eruption on the opposite side of the caldera at Tavurvur. Vulcan's ash leachates indicate seawater interaction that is consistent with earlier observations of low sulfur dioxide emissions and the presence of ice crystals in the initial plinian eruption cloud. In contrast, Tavurvur ash leachates indicate no seawater interaction, and later sulfur dioxide emissions remained high despite low-level eruptive activity. Silicic melt inclusions indicate that the andesitic melt contained about 2 weight percent water and negligible carbon dioxide. Mafic melt inclusions in Tavurvur ash have water and carbon dioxide contents that vary systematically over the course of the eruption. The mafic melt inclusions suggest that a mafic dike intruded from below the silicic chamber and provide further evidence that mafic intrusions drive caldera unrest.

Journal Article↗
PubMed1976

Carbon metabolism in model microbial systems from a temperate salt marsh.

The metabolism of a saltwater leachate of 14C-labeled Spartina alterniflora was examined in laboratory systems using mixed, salt marsh microbial communities and, by addition of appropriate antibiotics, communities with bacteria or eukaryotes inhibited. Label uptake was more rapid in the systems with bacteria alone and with the mixed microbial community than with fungi alone. Mineralization of the added label was more extensive in the mixed and bacterial systems, whereas the fungi appear more efficient at converting the label into particulate biomass. Particulate biomass production efficiencies ranged from a high of 0.82 for the fungal system to 0.21 in the mixed community, with the bacterial system giving an intermediate value of 0.54. The presence of protozoa and microcrustaceans in the mixed system appears to account for an increase in the mineralization of the label assimilated. Additional experiments with whole labeled Spartina, a leachate from Spartina, and Spartina after leaching revealed that the seawater-soluble portions of the plants were attacked most rapidly by the microbial community.

Animals↗
PubMed1985

Response of bacteria isolated from a pristine prairie stream to concentration and source of soluble organic carbon.

Responses of native aquatic bacteria to source and concentration of dissolved organic carbon was observed by using gradient plates. Dissolved organic carbon of prairie (grasses) or gallery forest (bur oak) origin was used as the carbon source in these observations. Bacteria isolated from sediments in the grassland reaches of a prairie stream showed growth only on grass leachates. Bacteria isolated from the gallery forest reaches of the same stream were able to grow on plates made from either source of leachate. The differing quality, quantity, and rate of supply of these dissolved organic carbon sources should select for variation in the bacterial assemblages.

Journal Article↗
PubMed1997

Acquisition of a deliberately introduced phenol degradation operon, pheBA, by different indigenous Pseudomonas species.

Horizontal transfer of genes of selective value in an environment 6 years after their introduction into a watershed has been observed. Expression of the gene pheA, which encodes phenol monooxygenase and is linked to the pheBA operon (A. Nurk, L. Kasak, and M. Kivisaar, Gene 102:13-18, 1991), allows pseudomonads to use phenol as a growth substrate. Pseudomonas putida strains carrying this operon on a plasmid were used for bioremediation after an accidental fire in the Estonia oil shale mine in Estonia in 1988. The water samples used for studying the fate of the genes introduced were collected in 1994. The same gene cluster was also detected in Pseudomonas strains isolated from water samples of a nearby watershed which has been continuously polluted with phenols due to oil shale industry leachate. Together with the more frequently existing counterparts of the dmp genes (V. Shingler, J. Powlowski, and U. Marklund, J. Bacteriol. 174:711-724, 1992), the pheA gene was also represented in the phenol-degrading strains. The area where the strains containing the pheA gene were found was restricted to the regular route of phenolic leachate to the Baltic Sea. Nine Pseudomonas strains belonging to four different species (P. corrugata, P. fragi, P. stutzeri, and P. fluorescens biotypes B, C, and F) and harboring horizontally transferred pheBA operons were investigated. The phe genes were clustered in the same manner in these nine phe operons and were connected to the same promoter as in the case of the original pheBA operon. One 10.6-kb plasmid carrying a pheBA gene cluster was sequenced, and the structure of the rearranged pheBA operon was described. This data indicates that introduced genetic material could, if it encodes a beneficial capability, enrich the natural genetic variety for biodegradation.

Base Sequence↗
PubMed1997

Nutrient leaching and end product accumulation in plastic composite supports for L-(+)-lactic Acid biofilm fermentation.

Investigations on the leachate bioavailability, leaching rate, and lactic acid accumulation properties of plastic composite supports (PCS) were essential for large-scale or long-term lactic acid fermentation. Leachates from PCS and polypropylene discs (controls) were analyzed by the micro-Kjeldahl method; by absorbances at 260, 275, and 280 nm; and by bioassays with Lactobacillus casei subsp. rhamnosus (ATCC 11443). The amount of leached nitrogen in a 20-ml initial soaking solution had a high correlation with the soaking solution's cell density (r = 0.87) and absorbance at 260 nm (r = 0.95). Leaching rates of various PCS were evaluated by 20 20-ml simulated repeated-batch fermentations (RBF). PCS with only yeast extract as the minor agricultural ingredient had a high leaching rate and leached out 51 to 60% of the total nitrogen during the first RBF. PCS blended with dried bovine albumin, dried bovine erythrocytes, and/or soybean flour had slowed nutrient leaching (20 to 30% of the initial leached nitrogen). Hence, they could still maintain 1 g of lactic acid per liter and measurable cell density (absorbance at 620 nm, 0.4 to 0.6) at the 20th 20-ml RBF. Lactic acid accumulation properties of PCS were evaluated by soaking the supports in a 30% lactic acid solution for 72 h at 45(deg)C. The lactic acid-soaked supports were rinsed three times and then heat treated (121(deg)C, 15 min) in 15 ml of deionized water. The results showed that lactic acid accumulation in PCS was mainly due to absorption and had no correlation with lactic acid production or biofilm formation.

Journal Article↗
PubMed2004

Alkaline anaerobic respiration: isolation and characterization of a novel alkaliphilic and metal-reducing bacterium.

Iron-reducing enrichments were obtained from leachate ponds at the U.S. Borax Company in Boron, Calif. Based on partial small-subunit (SSU) rRNA gene sequences (approximately 500 nucleotides), six isolates shared 98.9% nucleotide identity. As a representative, the isolate QYMF was selected for further analysis. QYMF could be grown with Fe(III)-citrate, Fe(III)-EDTA, Co(III)-EDTA, or Cr(VI) as electron acceptors, and yeast extract and lactate could serve as electron donors. Growth during iron reduction occurred over the pH range of 7.5 to 11.0 (optimum, pH 9.5), a sodium chloride range of 0 to 80 g/liter (optimum, 20 g/liter), and a temperature range of 4 to 45 degrees C (optimum, approximately 35 degrees C), and iron precipitates were formed. QYMF was a strict anaerobe that could be grown in the presence of borax, and the cells were straight rods that produced endospores. Sodium chloride and yeast extract stimulated growth. Phylogenetic analysis of the SSU rRNA gene indicated that the bacterium was a low-G+C gram-positive microorganism and had 96 and 92% nucleotide identity with Alkaliphilus transvaalensis and Alkaliphilus crotonatoxidans, respectively. The major phospholipid fatty acids were 14:1, 16:1omega7c, and 16:0, which were different from those of other alkaliphiles but similar to those of reported iron-reducing bacteria. The results demonstrated that the isolate might represent a novel metal-reducing alkaliphilic species. The name Alkaliphilus metalliredigens sp. nov. is proposed. The isolation and activity of metal-reducing bacteria from borax-contaminated leachate ponds suggest that bioremediation of metal-contaminated alkaline environments may be feasible and have implications for alkaline anaerobic respiration.

Bacteria, Anaerobic↗
PubMed2005

Geobacteraceae community composition is related to hydrochemistry and biodegradation in an iron-reducing aquifer polluted by a neighboring landfill.

Relationships between community composition of the iron-reducing Geobacteraceae, pollution levels, and the occurrence of biodegradation were established for an iron-reducing aquifer polluted with landfill leachate by using cultivation-independent Geobacteraceae 16S rRNA gene-targeting techniques. Numerical analysis of denaturing gradient gel electrophoresis (DGGE) profiles and sequencing revealed a high Geobacteraceae diversity and showed that community composition within the leachate plume differed considerably from that of the unpolluted aquifer. This suggests that pollution has selected for specific species out of a large pool of Geobacteraceae. DGGE profiles of polluted groundwater taken near the landfill (6- to 39-m distance) clustered together. DGGE profiles from less-polluted groundwater taken further downstream did not fall in the same cluster. Several individual DGGE bands were indicative of either the redox process or the level of pollution. This included a pollution-indicative band that dominated the DGGE profiles from groundwater samples taken close to the landfill (6 to 39 m distance). The clustering of these profiles and the dominance by a single DGGE band corresponded to the part of the aquifer where organic micropollutants and reactive dissolved organic matter were attenuated at relatively high rates.

Biodegradation, Environmental↗