5.0 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Bioremediation | 3/3 | https://en.wikipedia.org/wiki/Bioremediation | reference | science, encyclopedia | 2026-05-05T07:17:17.028374+00:00 | kb-cron |
=== Pesticides === Of the many ways to deal with pesticide contamination, bioremediation promises to be more effective. Many sites around the world are contaminated with agrichemicals. These agrichemicals often resist biodegradation, by design. Harming all manners of organic life with long term health issues such as cancer, rashes, blindness, paralysis, and mental illness. An example is Lindane which was a commonly used insecticide in the 20th century. Long time exposure poses a serious threat to humans and the surrounding ecosystem. Lindane reduces the potential of beneficial bacteria in the soil such as nitrogen fixation cyanobacteria. As well as causing central nervous system issues in smaller mammals such as seizures, dizziness, and even death. What makes it so harmful to these organisms is how quickly distributed it gets through the brain and fatty tissues. While Lindane has been mostly limited to specific use, it is still produced and used around the world. Actinobacteria has been a promising candidate in situ technique specifically for removing pesticides. When certain strains of Actinobacteria have been grouped together, their efficiency in degrading pesticides has enhanced. As well as being a reusable technique that strengthens through further use by limiting the migration space of these cells to target specific areas and not fully consume their cleansing abilities. Despite encouraging results, Actinobacteria has only been used in controlled lab settings and will need further development in finding the cost effectiveness and scalability of use.
== Limitations of bioremediation == Bioremediation is rarely employed to remediate pollutants. Heavy metals and radionuclides simply do not biodegrade, although in some cases, these metals can be immobilized. In some cases, microbes do not fully mineralize the pollutant, potentially producing a more toxic compound. For example, under anaerobic conditions, the reductive dehalogenation of TCE may produce dichloroethylene (DCE) and vinyl chloride (VC), which are suspected or known carcinogens. However, the microorganism Dehalococcoides can further reduce DCE and VC to the non-toxic product ethene. The molecular pathways for bioremediation are of considerable interest. In addition, knowing these pathways will help develop new technologies that can deal with sites that have uneven distributions of a mixture of contaminants. Biodegradation requires microbial population with the metabolic capacity to degrade the pollutant in a suitable timeframe. The biological processes used by these microbes are highly specific, therefore, many environmental factors must be taken into account and regulated as well. It can be difficult to extrapolate the results from the small-scale test studies into big field operations. In many cases, bioremediation takes more time than other alternatives such as land filling and incineration. Another example is bioventing, which is inexpensive to bioremediate contaminated sites, however, this process is extensive and can take a few years to decontaminate a site. Another major challeng is invasive species: indigenous species are preferred. The organism must be sufficiently plentiful to clean the site. Pesticides are a top contributor to soil contamination and runoff contamination. Pesticides are difficult to biodegrade.
== Genetic engineering == The use of genetic engineering to create organisms specifically designed for bioremediation is under preliminary research. Two category of genes can be inserted in the organism: degradative genes, which encode proteins required for the degradation of pollutants, and reporter genes, which encode proteins able to monitor pollution levels. Numerous members of Pseudomonas have been modified with the lux gene for the detection of the polyaromatic hydrocarbon naphthalene. A field test for the release of the modified organism has been successful on a moderately large scale. There are concerns surrounding release and containment of genetically modified organisms into the environment due to the potential of horizontal gene transfer. Genetically modified organisms are classified and controlled under the Toxic Substances Control Act of 1976 under United States Environmental Protection Agency. Measures have been created to address these concerns. Organisms can be modified such that they can only survive and grow under specific sets of environmental conditions. In addition, the tracking of modified organisms can be made easier with the insertion of bioluminescence genes for visual identification. Genetically modified organisms have been created to treat oil spills and break down certain plastics (PET).
== See also ==
== References ==
== External links == Phytoremediation, hosted by the Missouri Botanical Garden To remediate or to not remediate? Anaerobic Bioremediation