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PubMed2007

Bioremediation potential of live and dead Spirulina: spectroscopic, kinetics and SEM studies.

Metal binding by algae has enormous potential for environmental bioremediation targeting towards detoxification of water bodies. The present work reports the use of live and dead Spirulina sp. for sorption of metals like Cr(3+), Ni(2+), Cu(2+), and Cr(6+) in form of Cr(2)O(7)(2-). Preliminary investigation shows that this biomass takes up substantial amount of metal ions indicated above. IR spectroscopic study, kinetics models, Langmuir and Freundlich adsorption isotherms, SEM analysis, and fluorescence microscopic study of Spirulina sp. and the Spirulina sp. treated with different metal ions have been employed to understand the sorption mechanism. It is hoped that live Spirulina sp. will be a strong candidate for management of industrial wastewater.

Adsorption↗

PubMed2007

Performance of a low cost MBT prior to landfilling: study of the biological treatment of size reduced MSW without mechanical sorting.

In France, the interest in Mechanical Biological Treatment (MBT) prior to landfilling is actually growing. In the absence of acceptance criteria for the waste to be landfilled, an alternative to the intensive, high-technology MBT can only find its place in the French context if it shows substantial benefits from an environmental, economic or operational point of view. This paper presents an experiment of low-cost MBT of size reduced MSW without material splitting. The performance of an experimental, pilot-scale mechanical and biological treatment process has been studied on 37.5 Mg of raw municipal solid waste. The mechanical process has been kept simple with only coarse shredding and no material recovery. The biological treatment, which was a low-cost forced aeration process, was monitored for 25 weeks. The biogas production potential of the waste was reduced by 90% to 19 NL kgDM(-1). The initial AT4 index of 82.9 mg O2 gDM(-1) decreased to 16.0 mg O2 gDM(-1). After 25 weeks of aerobic treatment, the dry mass loss reached 37%, while the mass of waste going to landfill was reduced by 28%. The average performances of the process were explained by the biological process itself, which was not optimal, and also by the characteristics of the input waste. The high particle size of the treated waste and the high content of slowly biodegradable matter (such as paper and cardboard) may both be significant drawbacks for the biological stabilisation of waste.

Aerobiosis↗

PubMed2003

Nutrient removal from piggery effluent using vertical flow constructed wetlands in southern Brazil.

Santa Catarina State, southern Brazil, has the greatest swine breeding activities of Latin America. Generally, the piggery wastewater is treated in pond systems that are able to remove organic material according to local environmental legislation. However, these systems do not remove nitrogen and phosphorus efficiently. This work deals with a post-treatment system, using vertical flow constructed wetlands. The experiment was conducted in a swine production farm which has 45,000 animals. Although the pond system was able to partially remove the content of nutrients, their concentration in the effluent was high for environmental disposal. A four-bed vertical flow constructed wetland pilot plant, using Typha spp., was built. The pilot plant operated for 280 days for beds 2-4 (sand 2). However, the experiments with beds 1-3 (sand 1) were stopped after 111 days of operation, when a reduction in the wastewater drainage was observed. The beds with sand 2 showed a 33% COD removal, and about 49% of nitrification was observed from 111 days until the end of the operation. PO(4)-P removal was 45% with a loading rate of around 1.36 g m(-2) d(-1).

Animals↗

PubMed2003

[Degradation kinetics for Fhhh strain in PTA wastewater].

Degradation kinetics of the purified terephthalic acid (PTA) petrochemical wastewater with the functional strain Fhhh was conducted in this research. Inputting the values of the 6 kinetics parameters obtained from the test, the values of the natural parameter and the values of the standard parameters for discharging wastewater into the environmental biotechnological informatics software (Ebis), the minimum reactor volume (Vmin) required and the specific degradation rate (qA) were calculated based on the activated sludge process. The minimum value of Vmin was 1309 m3 as well as the highest value of qA was 0.0136 h-1 among the Fhhh preparations kept in three different methods. The highest value of Fhhh qA was 4 fold of that of the native bacterium YZ1, and higher than that of the data published by 4 researchers and lower than that of by 2 researchers. The results show that Fhhh has the obvious potential for the degradation of PTA wastewater.

Biodegradation, Environmental↗

PubMed2003

Bio-diversity: an effective safety net against environmental pollution.

Biodiversity is the feedstock for the biotechnology industry. Hence, the conservation, enhancement and sustainable and equitable use of biodiversity should be accorded high priority in all national environment protection programmes. Lichens serve as useful indicators of environmental health. Similarly, several blue green algae help to sequester salt from water. There is need for the more widespread use of such biomonitoring and bioremediation agents. Bioprospecting research designed to identify novel metabolites must be rooted in the principle of equity in sharing benefits with the holders of traditional knowledge. There is need for greater vigil against alien invasive species, since with growing world trade in food grains and other agricultural commodities, there is an increasing possibility of introducing new pests, weeds and harmful micro-organisms. Finally, biological scientists should place emphasis on their ethical responsibility for the consequences of their research, since otherwise bioterrorism could become a major threat to human security.

Animals↗

PubMed2002

Oxidation of chlorinated dibenzo-p-dioxin and dibenzofuran by white-rot fungus, Phlebia lindtneri.

The actions of a white-rot fungus on two chlorinated aromatic compounds, known to be persistent environmental contaminants, were studied. Two models, both-ring chlorinated dioxin, 2,7-dichlorodibenzo-p-dioxin (2,7-diCDD) and 2,8-dichlorodibenzofuran (2,8-diCDF), were metabolized by the white-rot fungus Phlebia lindtneri. 2,7-DiCDD disappeared linearly in the culture of P. lindtneri; over a 20-day incubation period, with only 45% remaining in the culture. One of the metabolites produced by P. lindtneri from a 5-day incubated culture with 2,7-diCDD or 2,8-diCDF was identified by gas chromatography-mass spectrometry. P. lindtneri was shown to metabolize 2,7-diCDD and 2,8-diCDF to hydroxy-diCDD and hydroxy-diCDF, respectively.

Basidiomycota↗

PubMed1991

Microbiological degradation of pesticides in yard waste composting.

Changes in public opinion and legislation have led to the general recognition that solid waste treatment practices must be changed. Solid-waste disposal by landfill is becoming increasingly expensive and regulated and no longer represents a long-term option in view of limited land space and environmental problems. Yard waste, a significant component of municipal solid waste, has previously not been separated from the municipal solid-waste stream. The treatment of municipal solid waste including yard waste must urgently be addressed because disposal via landfill will be prohibited by legislation. Separation of yard waste from municipal solid waste will be mandated in many localities, thus stressing the importance of scrutinizing current composting practices in treating grass clippings, leaves, and other yard residues. Yard waste poses a potential environmental health problem as a result of the widespread use of pesticides in lawn and tree care and the persistence of the residues of these chemicals in plant tissue. Yard waste containing pesticides may present a problem due to the recalcitrant and toxic nature of the pesticide molecules. Current composting processes are based on various modifications of either window systems or in-vessel systems. Both types of processes are ultimately dependent on microbial bioconversions of organic material to innocuous end products. The critical stage of the composting process is the thermophilic phase. The fate and mechanism of removal of pesticides in composting processes is largely unknown and in need of comprehensive analysis.

Biodegradation, Environmental↗

PubMed2003

Phytoremediation of heavy metals from soils.

Phytoremediation offers owners and managers of metal-contaminated sites an innovative and cost-effective option to address recalcitrant environmental contaminants. The use of plants or plant products to restore or stabilize contaminated sites, collectively known as phytoremediation, takes advantage of the natural abilities of plants to take up, accumulate, store, or degrade organic and inorganic substances. Although not a new concept, phytoremediation is currently being re-examined as an environmentally friendly, cost-effective means of reducing metal contaminated soil and other substrates throughout North America and Europe. Processes include using plants that tolerate and accumulate metals at high levels (phytoextraction) and using plants that can grow under conditions that are toxic to other plants while preventing, for example, soil erosion (phytostabilization). Governments worldwide are establishing research and demonstration programs to use this potential. Environment Canada has developed a database (PHYTOREM) of 775 plants with capabilities to accumulate or hyperaccumulate one or several of 19 key metallic elements. This chapter addresses key research, potential benefits and limitations, and the potential future needs for phytoremediation. Issues related to intellectual property law, commercialization and public acceptance are touched on.

Animals↗

PubMed2004

BETR-World: a geographically explicit model of chemical fate: application to transport of alpha-HCH to the Arctic.

The Berkeley-Trent (BETR)-World model, a 25 compartment, geographically explicit fugacity-based model is described and applied to evaluate the transport of chemicals from temperate source regions to receptor regions (such as the Arctic). The model was parameterized using GIS and an array of digital data on weather, oceans, freshwater, vegetation and geo-political boundaries. This version of the BETR model framework includes modification of atmospheric degradation rates by seasonally variable hydroxyl radical concentrations and temperature. Degradation rates in all other compartments vary with seasonally changing temperature. Deposition to the deep ocean has been included as a loss mechanism. A case study was undertaken for alpha-HCH. Dynamic emission scenarios were estimated for each of the 25 regions. Predicted environmental concentrations showed good agreement with measured values for the northern regions in air, and fresh and oceanic water and with the results from a previous model of global chemical fate. Potential for long-range transport and deposition to the Arctic region was assessed using a Transfer Efficiency combined with estimated emissions. European regions and the Orient including China have a high potential to contribute alpha-HCH contamination in the Arctic due to high rates of emission in these regions despite low Transfer Efficiencies. Sensitivity analyses reveal that the performance and reliability of the model is strongly influenced by parameters controlling degradation rates.

Air Pollutants↗

PubMed1998

Bioaccumulation and retention of lead in the mussel Mytilus galloprovincialis following uptake from seawater.

Bioaccumulation of lead in the mussel Mytilus galloprovincialis from 210Pb-labeled bulk seawater (dissolved and particulate pathways combined) was examined over 21 days. The lead bioaccumulation factor (BAF) at equilibrium was estimated to be 211 +/- 10 ml g-1. This value was two orders of magnitude lower than BAFs reported in the literature for other trace metals in this bivalve indicating that lead is not efficiently accumulated by mussels from bulk seawater. The resultant lead distribution in mussels was 49 +/- 10% in soft tissues and 46 +/- 16% in the shell suggesting similar uptake rates (Bq day-1) in both compartments throughout the exposure. Total elimination for lead in mussels was adequately described by a short-term compartment with a biological half-life for loss of 1.4 +/- 0.3 days and a long-term compartment which released lead only very slowly (Tb1/2 = 2.5 +/- 0.7 months). No difference was noted for lead elimination rates in shell and in soft parts. When experimentally exposed to lead under conditions representative of natural environmental lead levels in water, including both that in the dissolved phase and in the food, the shell compartment was shown to contain the major fraction of the total lead accumulated by mussels. Therefore mussels may be considered as good bioindicators of lead contamination accumulated from the dissolved rather than from the particulate source. Furthermore, the relatively slow uptake and the long depuration half-life of lead will limit the ability of mussels to accurately record short-term variations in lead concentrations in the surrounding waters, a fact which should be taken into consideration in order to define the appropriate sampling frequency for mussels used in biomonitoring programs involving lead.

Animals↗

PubMed2003

Source apportionment of PAHs in dated sediments from the Black River, Ohio.

Black River, OH, is contaminated with polycyclic aromatic hydrocarbons (PAHs) from coke ovens of a US Steel Corp. Plant. Closing of a coking plant in 1983 and environmental dredging of the sediments during 1989 and 1990 has reduced the PAH levels significantly. This study quantifies the decrease, and consider source apportionment of PAHs in Black River sediments using chemical mass balance modeling. Five vibra cores collected in 1998 and dated using 210Pb and 137Cs, were analyzed for 18 PAHs. The cores had total PAH concentrations between 250 and 0.10 ppm. PAH maxima occur in 1949, 1969, in accordance with regional historical inputs (core BR4), and in 1991 due to remediation (BR6). Coke oven emissions (CO), highway dust (HWY), and wood burning (WB) are likely sources. The CO source (6-92% of total PAHs) is maximal in 1954, and again in 1992-1994 due to the exposure and redistribution of older contaminated sediments during dredging, and decreases thereafter. There is minimal CO content in 1985 (BR4), 2 yr after closure of the coking plant. The HWY contribution (2-86%) is high during 1969-1988, and increases again after 1993. The WB source is less than 23%, and exhibits a minimum (2%) around 1979 (BR4). There is evidence of aerobic biodegradation or photolysis in the sediment of phenanthrene (PhA) at PhA concentrations >500 ppb.

Biodegradation, Environmental↗

PubMed1996

Influence of environmental parameters on pentachlorophenol biotransformation in soil by Lentinula edodes and Phanerochaete chrysosporium.

The influences of temperature, soil moisture potential and initial pH on the biotransformation of pentachlorophenol (PCP) by the lignicolous fungi Lentinula edodes and Phanerochaete chrysosporium were examined. At 10 degrees C, L. edodes was more effective in degrading PCP (P < 0.05) than P. chrysosporium. At 15 degrees C similar results were obtained for the two fungi. The highest levels of degradation occurred for both fungi at 25 degrees C. With P. chrysosporium, the extent of PCP elimination was directly related to soil moisture content and optimal at approximately 47%. With L. edodes, in contrast, the process was inversely related to moisture content and maximal at 26%. The initial soil pH also had a marked influence, and pH 4.0 was optimal for both fungi.

Agaricales↗

PubMed2005

Di-(2-ethylhexyl)phthalate in sewage sludge and post-treated sludge: quantitative determination by HRGC-MS and mass spectral characterization.

DEHP was quantified into sewage sludge, thermally dried sludge and compost samples from different areas of Catalonia (North East Spain) using high-resolution gas chromatography (HRGC) coupled to a mass spectrometry (MS). The aim of the work was to determine the evolution of this ubiquitous environmental contaminant along some post-treatment sludge processes, such as composting and thermally drying. DEHP concentration detected in some sludges are above the maximum limit suggested by the EC (100 ppm d.m.) for agricultural use. However, the composting and thermally drying reduce the amount of DEHP in sewage sludge to acceptable level for safe land application. The study was completed with the characterization and long-term observation of DEHP in sewage sludge, composted sludge and thermally dried sludge mixed with two types of soils. In all cases, the percentage of DEHP degraded was higher than 50% after 9 months of incubation.

Biodegradation, Environmental↗

PubMed2005

From papyrus to compact disc: the microbial deterioration of documentary heritage.

Highly significant evidence of the intellectual and cultural efforts of the human race is contained in documents. They take many forms, from papyri through paper to modern magnetic media and optical records. These items are mainly made of organic materials many of which contain polymers, which span from cellulose and its derivatives to synthetic resins. As with other manmade objects, however, documentary heritage is susceptible to chemical, physical, and biological damage. For the colonization and establishment of any biological community, the composition of materials used, their status of conservation, and environmental and climatic factors, such as temperature and humidity, are important elements to take into account. This article covers the scientific investigation of microbial degradation of documents, which is one of the most serious and underappreciated sources of damage to library and archival materials. In particular, although less known, modern records, including compact discs, are also subjected to biodeterioration. Archival and library material preservation broadly encompasses those activities and functions designed to produce a suitable and safe environment that extends the life of collections in useable condition for as long as is feasible. In the literature quoted, key information is also provided to avoid or limit microbial growth and some conservation treatments are also reported.

Animals↗

PubMedDate not supplied

Phytoremediation: biological cleaning of a polluted environment.

Phytoremediation is the direct use of living green plants to degrade, contain, or render harmless various environmental contaminants, including recalcitrant organic compounds or heavy metals. The methods involved include phytoextraction, direct phytodegradation, rhizofiltration, phytovolatilization or formation of artificial wetlands, and lagoon systems. More research background and the development of plants tailored for remediation purposes, using genetic engineering and deeper understanding of plant cooperation with microorganisms is needed. This approach is illustrated by our studies of heavy metal uptake improvement or studies of the PCB conversion, which include in-vitro screening of plant species, analysis of the products, evaluation of their toxicity and field plots, and also studies of enzymes and cloning of foreign genes into plants.

Biodegradation, Environmental↗

PubMed2002

Microbial dehalorespiration with 1,1,1-trichloroethane.

1,1,1-Trichloroethane (TCA) is a ubiquitous environmental pollutant because of its widespread use as an industrial solvent, its improper disposal, and its substantial emission to the atmosphere. We report the isolation of an anaerobic bacterium, strain TCA1, that reductively dechlorinates TCA to 1,1-dichloroethane and chloroethane. Strain TCA1 required H2 as an electron donor and TCA as an electron acceptor for growth, indicating that dechlorination is a respiratory process. Phylogenetic analysis indicated that strain TCA1 is related to gram-positive bacteria with low DNA G+C content and that its closest relative is Dehalobacter restrictus, an obligate H2-oxidizing, chloroethene-respiring bacterium.

Anaerobiosis↗

PubMed2002

Remediation of BTEX and trichloroethene. Current knowledge with special emphasis on phytoremediation.

The widespread use of industrial chemicals in our highly industrialized society has often caused contamination of large terrestrial and marine areas due to the deliberate and accidental release of organic pollutants into the soil and groundwater. In this review, environmental problems arising from the use of chlorinated solvents and BTEX compounds are described, and an overview about active management strategies for remediation with special emphasis on phytoremediation are presented to achieve a reduction of the total mass of chlorinated solvents and BTEX compounds in contaminated areas. Phytoremediation has been proposed as an efficient, low-cost remediation technique to restore areas contaminated with chlorinated solvents and BTEX compounds. The feasibility of phytoremediation as a remediation tool for these compounds is discussed with particular reference to the uptake and metabolism of these compounds, and a future perspective on the use of phytoremediation for the removal of chlorinated solvents and BTEX compounds is given.

Animals↗

PubMed1989

Enrichment of dibenzofuran utilizing bacteria with high co-metabolic potential towards dibenzodioxin and other anellated aromatics.

Dibenzofuran degrading bacteria were enriched from various environmental sources. A mutualistic mixed culture of strain DPO 220 and strain DPO 230 was characterized. Strain DPO 220 alone showed limited growth with dibenzofuran as sole source of carbon and energy (td greater than or equal to 4.5 h). A labile degradation product, C12H10O5, and salicylate were isolated from the culture fluid. Salicylate was found to be a central intermediate of DBF-degradation. Strain DPO 220 co-metabolized a wide range of anellated aromatics as well as heteroaromatics. High rates of co-oxidation of dibenzodioxin demonstrate analogue-enrichment to be a powerful technique for selecting enzymatic activities for otherwise non-degradable substrates.

Bacteria↗