Discussion Forums for the people of Paete, Laguna, Philippines
Joined: 06 Jul 2005
Location: Angel C. de Dios
|Posted: Mon Jul 17, 2006 10:35 am Post subject: (Environment) Bioremediation: Hope of Environment
Bioremediation: Hope of environment
ASUNCION K. RAYMUNDO, Ph.D
Professor, UP-Los Baños
Head, Bioremediation Research Team
OUR country keeps on generating tons of toxic and hazardous wastes generally from industries; these are in addition to existing dumpsites like abandoned mines that harbor high levels of pollutants. While some industries claim to manage their toxic wastes properly, environment and health issues related to toxic and hazardous wastes persist. Bioremediation appears to be an approach that is feasible and gives us hope for our environment. Bioremediation is the use of biological entities, either plants (phytoremediation) or microbes (microbial remediation), which are capable of degrading or transforming pollutants into less hazardous forms or even immobilizing them. The diverse metabolic capabilities of biological entities can be harnessed for the degradation or transformation of toxic and hazardous wastes.
Bioremediation has found many applications in other countries. It has been used to remediate oil-contaminated soils in the United States, Europe, and Iraq and in some cases restore them to their original crop production capacity. In the Philippines, bioremediation is almost unheard of. In response to these pollution issues, a Bioremediation Research Team (BRT) was formed under the auspices of the National Academy of Science and Technology. After a series of meetings, the team decided to focus on abandoned mines, an unattended source of hazardous waste.
As a result of Executive Order No. 270 — the National Policy Agenda on Revitalizing Mining in the Philippines — last 16 January 2004, as well as the favorable Supreme Court decision on the Philippine Mining Act 7942 of 1995, we are witnessing the revitalization of the local minerals industry, which had become nearly dormant prior to the decision. Such actions have made the government and the private sector hopeful that the mining industry can provide a much-needed boost to our economy.
There are two main issues attached to the mining industry: abandoned mines and the management of mine wastes. In 2004, the Mining and Geology Bureau reported 22 abandoned mines. Phytoremediaton is the approach that is most applicable to these abandoned mines. From the limited analysis done by the group which was spearheaded by Dr. Veronica Migo, it was established that indeed the concentrations of heavy metals are way beyond tolerable limits for soil and much more for sources of drinking water.
To meet the challenges posed by these problems, we have proposed the following projects: Field Tests of Phytoremediation and Microbial Technologies for the Rehabilitation of Contaminated Mine Sites. The Phytoremediation Group of BRT, composed of Drs. Nina Cadiz, Nelly Aggangan and Nelson Pampolina of UPLB, has done an inventory of heavy metal resistant plants that can be used for phytoremediation and developed technologies to ensure a higher survival rate of seedlings (microbial inoculation). Plant species that can be planted in abandoned mines have been identified and research on how to increase their survival rate for phytoremediation use has been done. Through microbial inoculation, plants that cannot tolerate 750 µM of copper can be induced to grow well. The microbes used are mycorrhiza, which are fungi that grow in the roots of plants and assist the latter in nutrient absorption. These fungi promote rapid plant growth, consequently increasing the survival rate of plants even under stressed conditions.
Jatropha curcas, commonly known as "tubang bakod", is another promising plant species for phytoremediation. As its nuts can be used as a source of biodiesel, there are now existing programs for its production and utilization as an alternative energy source. The potential of the Jatropha as a phytoremediation species can be enhanced by microbial inoculation. The following issues need to be addressed before it becomes widely used in abandoned mines: 1) Do heavy metals get translocated to the nuts? 2) Can strategies be developed to prevent heavy metal translocation to the nuts? 3) If heavy metals are found in the nuts, can they be separated from the oil that will be extracted? 4) Will the additional step still allow farmers to obtain profit from their Jatropha plantings? Research has to be undertaken in these areas.
Other work being conducted or being proposed is on "Local Bioremediationbased Technologies for the Management of Wastes from the Mining Industry". These are currently in the research and development phase. The group of Dr. Fidel Rey Nayve Jr. of BIOTECH-UPLB is developing "Bacterial Exopolysaccharide (EPS)" — a malunggay seed extract flocculation system for the removal of heavy metals from liquid waste streams. Exopolysaccharide is a sugar polymer that can be produced cheaply by growing the bacterium, Rhizobium, in an indigenous medium like coconut water. The bacterium grows and produces the extrapolysaccharide compound, EPS, which will then be extracted and introduced into the effluent. EPS will bind the heavy metals but the complex will remain suspended in the effluent. With the addition of malunggay seeds extract, a complex is formed that will precipitate the EPS-heavy metal complex. The effluent will become a clear liquid devoid of heavy metal contaminants, which can then be released into a body of water.
Another project, being proposed by the group of Dr. Lorele Trinidad of UPLB, which has potential in bioremediation is "The Use of Indigenous Microbes for the Bioremediation of Heavy Metal Contaminated Wastes and Effluents". The methodology proposed in this project consists of growing a group of microbes singly or together using agricultural wastes as binder. Dead cells like yeasts from distillery wastes will also be tried. Heavy metal contaminated water is then passed through the sorbent system, and the heavy metals will then stick to the microbial community, consequently cleaning effluents
The BRT, composed of microbiologists, chemists, environmentalists, and plant biologists, is confident that harnessing natural processes like bioremediation is imperative in the drive to maintain the soundness and integrity of the environment.
Questions to explore further this topic:
What is biodegradation?
What is bioremediation?
Does bioremediation work?
Find out how a bioremediation strategy based on nutrient enrichment was used to clean up over 100 kilometres of oil-contaminated shoreline.
Examples of bioremediation services
Pond and lake management
What is phytoremediation?
What is microbial remediation?
We're Microbes & Proud of It
Meet Conan the Bacterium
Anaerobes to the Rescue
Intimate Strangers: Unseen Life on Earth
What is composting?
Microbial biocatalytic reactions and biodegradation pathways
Microbe Power (Waste Management)
Composting at mine sites
Environmental Technology for Mining
Joined: 06 Jul 2005
Location: Angel C. de Dios
|Posted: Thu Jan 10, 2008 7:54 pm Post subject: Fighting pollution the poplar way: Trees to clean up Indiana
|January 10, 2008
Fighting pollution the poplar way: Trees to clean up Indiana site
Purdue University researchers are collaborating with Chrysler LLC in a project to use poplar trees to eliminate pollutants from a contaminated site in north-central Indiana.
The researchers plan to plant transgenic poplars at the site, a former oil storage facility near Kokomo, Ind., this summer. In a laboratory setting, the transgenic trees have been shown to be capable of absorbing trichloroethylene, or TCE, and other pollutants before processing them into harmless byproducts.
Richard Meilan, a Purdue associate professor, is currently at work to transform one variety of poplar suited to Indiana's climate; cold-hardy poplars are generally more difficult to alter than the variety used in a laboratory setting.
"This site presents the perfect opportunity to prove that poplars can get rid of pollution in the real world," Meilan said.
In a study Meilan co-authored, published last October in Proceedings of the National Academy of Sciences, poplar cuttings removed 90 percent of the TCE within a hydroponic solution in one week. The engineered trees also took up and metabolized the chemical 100 times faster than unaltered hybrid poplars, which have a limited ability to remove and degrade the contaminant on their own, he said.
The transgenic poplars contain an inserted gene that encodes an enzyme capable of breaking down TCE and a variety of other environmental pollutants, including chloroform, benzene, vinyl chloride and carbon tetrachloride.
Meilan said he believes the transgenic poplars will be able to remove the TCE from the site, named Peter's Pond, which was contaminated by tainted oil stored there in the 1960s. The chemical, used as an industrial solvent and degreaser, lies within 10 feet of the surface, making it accessible to poplar roots, he said.
TCE, the most common groundwater pollutant on Superfund sites, is a probable human carcinogen and causes various health problems when present in sufficiently high levels in water or air.
Meilan said planting transgenic trees in the field remains controversial, primarily due to concerns that inserted genes, or transgenes, might escape and incorporate into natural tree populations.
"It is legitimate to be concerned about transgenic plants, but we are taking comprehensive steps to ensure that our transgenes don't escape into the environment," Meilan said.
Meilan has applied for a permit to grow transgenic poplars in a field, or non-laboratory, setting from the Animal and Plant Health Inspection Service, the government organization responsible for regulating such research activities, he said.
In order to comply with permit guidelines and to protect the environment, Meilan's team will take measures to prevent any plant material from leaving the site and will remove the trees after three years, short of the five it takes for poplars to reach sexual maturity, he said.
"Three years should be enough time for them to grow up, send down roots to suck the pollutants up and break them down," Meilan said. "Then we'll cut them down before they have the chance to pass on their genes to the environment."
Besides their utility in phytoremediation, or pollution removal, poplars have promise as a feedstock for cellulosic ethanol. To investigate their potential in this area, the U.S. Department of Energy awarded a $1.3 million grant to Meilan and two colleagues, professors Michael Ladisch, agricultural and biological engineering, and lead researcher Clint Chapple, biochemistry.
They are currently investigating ways to alter the composition of poplar lignin, which provides rigidity to the plant cell wall by binding to strands of cellulose, a complex sugar that can be converted into ethanol.
Chrysler will fund the Kokomo project and said that the TCE is contained within an isolated water table at Peter's Pond and presents no public hazard.
The original study, led by University of Washington professors Stuart Strand and Sharon Doty, revealed that the transgenic poplars also were able to absorb TCE vapors through their leaves before metabolizing the chemical. Tree cuttings removed 79 percent of the airborne TCE from a chamber within one week. This suggests poplars could one day help mitigate air as well as water pollution.
If the project succeeds, poplars may be used for phytoremediation elsewhere. Poplars grow across a wide geographic range and in many different climates, Meilan said.
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