Restoring all our lands to useful, prosperous, multipurpose areas involves several key issues: safety of site, energy, resources, effectiveness of clean up and costs. Since our natural resources are priceless, it seems that money should be no object...but it is. Access and effectiveness of clean up of a toxic site is always a consideration based on costs, as well as a number of other pertinent issues. The estimated cost of just removing uranium from contaminated sites over the next 30 years hovers between 373 billion and 1.694 trillion. Those figures are just for the approximately 1000 US sites that have radioactive contamination. When adding in the costs of cleaning up other heavy metals and organics, (including petroleum by-products), and industrial waste, the cost goes from unreasonable to unmanageable. Seeking simple alternatives to high cost remediation seems the only lucid choice. Finding ways to clean up sites takes research, creativity, innovation, and a willingness to explore the possibilities beyond the conventional. Ironically, some of our most effective solutions may be uncomplicated, natural, and manageable utilization of resources already available. Other methods to be discussed use the best of cutting edge biotechnology and technical aptitude to create bio-helpers and biodegradables that have short term critical addressing, as well as long term management potentials. Using clever resource management, along with industrial, commercial, and ecological management & oversight can open doorways of opportunity to reduce and in some cases eliminate challenges that have long plagued the nuclear and industrial waste industries.
There are several areas of research and development that are providing options in hazardous waste management. Some of these options have the ability to be effectively utilized in soil, groundwater, and surface water cleansing. There are also some concerns that have been raised with respect to the implementation of these options. Solutions to some of those challenges will be presented here as well. It is hoped that the information presented will give an overview of options and solutions to a crucial area of energy and natural resource management.
One area of concentration that shows promise in its effectiveness in waste remediation and cost reduction is phytoremediation. Simply put, it is the introduction of botanicals whose properties and /or companion organisms have the ability to significantly reduce certain types of waste, (depending on the plant), and to restore the site to within safe levels in shorter periods of time, with extreme reduction in costs. There are several subdivisions of phytoremediation. All areas can play an important part in the versatility of site remediation approaches-utilizing more than one form, depending upon conditions and risks. Phytoremediation allows nature to do its job most effectively: balance, cleansing, renewing itself. We partner in this process by assisting when necessary, and this cooperative approach insures the most successful outcome with minimal invasiveness to the surrounding environment, which may be of major concern depending upon location, proximity, and region.
One type of phytoremediation that shows huge potential is phytodegradation. This is a process where the introduced botanical reduces and destroys unwanted organics and heavy metals including (but not limited to) most petroleum by-products, pesticides and explosives like TNT. They can be used at ground level, soil level and below, deep water, and even surface water remediation. One example is the use of fescus grass that cleaned up petroleum hydrocarbons in Astoria, Oregon in a very brief period of time, with no residue discovered in the plants. A series of complicated chemical events within the plant's root and stem system explain the phenomenon. In another case, poplar trees were planted in deep water that not only reduces the waste, but because they drink so rapidly, pulled the contaminants close to them and prevented further spread of the spill down the waterway. The significance of these trials is two fold: first, a remediation of undesirables and secondly, in the fact that the plant remains residue free. A combination of perennial plant partnering, recreating a natural meadow has had similar outcome in Tennessee in the absorption of TNT. The risk to herbivores from this type should be negligible, considering the risk of untreated contaminants pose a much greater risk. Some plants may actually store TNT, and it may reach high levels. Those shall be discussed in the following section, as they are a different classification of phytoremediation. Their risk is higher, and their solution to that problem involves additional cost, but ultimately, still a savings when compared to other forms of remediation. Most meadow perennials are phytodegradators that, when they do store their contaminants, it is usually at root level, keeping the toxins away from deer, rabbits, etc. and can actually cleanse themselves within three seasons. These strong perennials include Echinacea (augustafolia and purpurea), common forms of burdock (three types), and lobelia. The residues become quickly eliminated by plant processes and so disposal of contaminants becomes unnecessary. The advantages of this approach are obvious: reduced costs in remediation, transport, and little disturbance to surrounding areas make this an attractive option where communities or sensitive natural surroundings may be of concern. They are phytodegradators that cleanse themselves in a single season; some actually have partnering microorganisms that are the actual destroyers of the contaminants, and as a result, there is no residue to dispose of. This treatment option holds great possibility and should be explored fully to maximize potentials.
Phytoextraction is the ability of a botanical to take in toxins and store them. Some plants are very used to adapting to areas with high levels of zinc, nickel, and lead. Therefore, they also have the ability to absorb strontium, cesium, and uranium. Obviously, removal of heavy metals in soil and deep water would be easy for these types of plants; but the question may be concerning their effectiveness remediating toxins on the surface of water. Sunflowers were tied to natural rafts and sent through waterways near Chernobyl. In laboratory analysis, sunflowers were able to remove ninety percent of the contaminant in just ten days! The plant performed equally well in the water where they were constantly exposed to an increase in contamination every time it rained. In soil, sunflowers remediated petroleum wastes in Utah.
On the Clinton River Project near Detroit, using deep-rooted phytoextractors and creating natural retention ponds removed everything from organic to bacteriological contaminants. Where herbivores may not have adapted to plants with high concentrations of metals, the plants can be recycled and taken to secondary smelters (by industry that normally remove lead from, for example old batteries) and their biomass can be incinerated. Phytoextraction plants with quick maturity dates, depending on growing zones, may be removed and new plants replaced up to three times a year. Risks are going to vary widely, depending on sites and metals absorbed. While a bit more complicated, phytoextraction still reduces costs and risks in remediation. Sometimes, chelators are added to soil to coax lead out of the soil and into plants.
A third form of Phytoremediation is phytostabilization. The advantages are that most heavy metals are stored in the roots, away from herbivores and soil and water sources. Using roots sources that have the ability to cleanse themselves eliminates the need for removal from sensitive sites. Burdock and Echinacea are ideal candidates. Once remediated, these sites can become ideal areas for botanical propagation of these strong perennials for market sale to pharmacological and herbal remedy companies. Echinacea in particular is threatened, mostly due to the increase in its usage as a medicinal because of its antibiotic, antiviral, and immune bolstering properties. Planting more can create an economically enfranchising opportunity for communities or countries. Since burdock and Echinacea are both drought and flood resistant (that is, neither will be killed by these environmental conditions, and their potency will not be reduced by these conditions) and are extremely climate versatile, they become the best options in this type of remediation. Burdock does have a tendency to spread like wildfire and can behave parasitically, so monitoring its progress is essential.
The fourth type of phytoremediation is phytovolatilization. This is not the authors' favorite; mostly because there are too many complications we have no current solution to address. Further research is essential to overcome the shortcomings. Biogenetic engineering has created four botanicals that can absorb mercury and methyl-mercury, but they release it as a vapor into the air. Obvious problems with mercury being reintroduced into the soil via rainfall or even carried away elsewhere. Perhaps transporting contaminated material to storage sites utilizing the botanicals and controlling issues with vapor are an option. More research is definitely required before widespread implementation.
Another area where bioengineering and technical research may provide solutions where mercury is concerned is a process where separation by capillary electrophoresis using pulsed amperometric detection is employed. It is a process that is quite complicated, but removes mercury and methyl-mercury from waterways and even species. The importance of this procedure being successfully used more widely cannot be understated. Mercury is a monumental problem in waterways worldwide and in the US alone, over 30,000 people a year die from complications with consumption of seafood contaminated with mercury. Pregnant women have a host of fish and seafood they are now informed they cannot consume due to health dangers and the American Academy of Pediatrics has determined that young children should not eat more than one serving of tuna a week due to contamination and danger to the nervous system. More research and capital investment in areas where we can make headway in this arena is crucial to have safer waterways and food supply, a key to overall population wellness.
Utilizing anaerobic/aerobic processes are cost effective as well, and can be used in chemical, petrochemical, above ground reactor, subsurface and bioprocessing areas. A fluidized bed anaerobic/aerobic hybrid single-process surface and sub-surface bioreactive barriers are effective. This bio-film based system immobilizes microorganisms as well as provide opportunity for microbial monitoring. Priority has been given to chlorinated products, polycyclic aromatic hydrocarbons and nitroaromatics. Remediation and/or reduction and control of these specific pollutants can be used in a variety of regions.
One area of serious consideration with respect to remediation is uranium. There are a plethora of approaches being discussed to clean up contaminated sites. One solution receiving special attention is natural attenuation, using iron oxyhydroxides. The EPA considers this method of remediation as valid and useful. The Sandia Natural Attenuation Project is a multi-agency, multi-lab endeavor and its results are promising. Natural attenuation is irreversible absorption, it will not leech out once it is absorbed. It will work with radionuclides, heavy metals, and organics. It works at soil sites at Chernobyl because the isotope 137C sticks to mineral surfaces. It is a slower process and must be watched carefully because of risk to humans and animals. Since this project has involvement from EPA, the Nuclear Regulatory Commission, and DOE, the hope is that this project will continue and perhaps methods of accelerated absorption in a briefer time frame may be discovered. There have been many research projects at Chernobyl that have attempted to reduce contamination. One fascinating partnership between CGP (Consolidated Growers and Processors), Phytotech, (a US based phytoremediation firm) and the Ukraine's Institute of Bast Crops (a seed bank founded in 1931) used industrial hemp as a way of reducing contamination by phytodegradation-it worked extremely well. Through biogenetic engineering, the hemp seed used (there are 400 varieties) had all the measurable THC removed (not that there is much to begin with in industrial seed). The crop was residue free, probably due to a series of bacteria and organic organisms that live at the root site that destroy toxins even before any absorption takes place. Crops could be turned under for effective composting and increasing organic material in the soil. Increasing the remediation process at this site and others should be a high priority to make the area livable again and reduce additional complications and restrictions of natural resources. Improving remediation processes and improving soil quality equals increased enfranchisement and wellness for communities at large. We should give these possibilities our closest examination to determine overall viability in multiple markets.
Radiation resistant bacteria are being bioengineered to devour toxic metals and organics. Bacterium Deinococcus is designed to clean up toxic waste left at radioactive sites, especially where nuclear weapons were produced. Other recent developments like Oclansorb, which absorbs hydrocarbons (12 times its weight) , and can be incinerated after use without concern of release of toxins into the environment. It is completely biodegradable. It is developed by Hi-Point Industries, in Canada.
Obviously, there are a lot of considerations where parasite/organic overrun may be concerned. In wetland sites (as well as sub-tropical and tropical zones) the biomass used for remediation can be used as fuel pellets, soil conditioner, industrial products, and when determined safe, animal feed (26% crude protein). This will help keep sensitive areas in check and balance. Plant partnering reduces plants running wild over more sensitive plantings and monitoring becomes key. Many individuals can become employed, or have their employment redirected into conservation, natural resource, management, technology development, and bio-technical research. Many more are needed in bioengineering, botanical propagation, horticulture, and herbal study. Combining our human, financial, as well as natural resources, always with sensitivity and consideration about the sites approached, will guarantee our collective success in the vast area of remediation of contaminated areas. Our vision is broader, our commitment stronger than ever. We will take all our accumulated knowledge and explore our options fully; we truly cannot afford to do otherwise.
Stephanie N. Simmons