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Cleaning the Earth Nature’s Way – Phytoremediation.
Cleaning the Earth Nature’s Way – Phytoremediation.
Phytoremediation1,2 may be defined as the treatment of environmental problems by using plants in situ so to avoid the need to excavate the contaminant material for disposal elsewhere. It can be applied to the amelioration of contaminated soils, water, or air, using plants that can contain, degrade, or eliminate metals, pesticides, solvents, explosives, crude oil and its derivatives (refined fuels), and related contaminating materials. Phytoremediation has been used successfully for the restoration of abandoned metal-mine workings, and cleaning up sites where polychlorinated biphenyls have been dumped during manufacture, and for the mitigation of on-going coal mine discharges. Phytoremediation uses the natural ability of particular plants (“hyperaccumulators”, described below) to bioaccumulate, degrade, or otherwise reduce the environmental impact of contaminants in soils, water, or air. Those contaminants that have been successfully mitigated in phytoremediation projects worldwide are metals, pesticides, solvents, explosives, and crude oil and its derivatives, and the technology has become increasingly popular and has been employed at sites with soils contaminated with lead, uranium, and arsenic. A major disadvantage of phytoremediation is that it takes a relatively long time to achieve, because the process rests upon the ability of a plant to thrive in an environment that is not normally ideal for plants.
Advantages and limitations of phytoremediation.
- Advantages:
- In terms of cost, phytoremediation is lower than that of traditional processes both in situ and ex situ.
- The plants can be easily monitored.
- There is the possibility of the recovery and re-use of valuable metals (by companies specializing in “phyto-mining”).
- It is potentially the least harmful method because it uses naturally occurring organisms and preserves the environment in a more natural state.
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EPA’s New Fracking Study: A Close Look at the Numbers Buried in the Fine Print
EPA’s New Fracking Study: A Close Look at the Numbers Buried in the Fine Print
When EPA’s long-awaited draft assessment on fracking and drinking water supplies was released, the oil and gas industry triumphantly focused on a headline-making sentence: “We did not find evidence of widespread, systemic impacts on drinking water resources in the United States.”
But for fracking’s backers, a sense of victory may prove to be fleeting.
EPA’s draft assessment made one thing clear: fracking has repeatedly contaminated drinking water supplies (a fact that the industry has long aggressively denied).
Indeed, the federal government’s recognition that fracking can contaminate drinking water supplies may prove to have opened the floodgates, especially since EPA called attention to major gaps in the official record, due in part to gag orders for landowners who settle contamination claims and in part because there simply hasn’t been enough testing to know how widespread problems have become.
And although it’s been less than a month since EPA’s draft assessment was released, the evidence on fracking’s impacts has continued to roll in.
A study in Texas’ Barnett shale found high levels of pollutants – volatile organic compounds, heavy metals, and known carcinogens – in many people’s drinking water, based on testing from over 500 water wells. The contaminants found were associated with the shale drilling industry, but the researchers cautioned it was too soon to say whether the industry actually caused the contamination.
But the association was strong, the researchers said. “In the counties where there is more unconventional oil and gas development, the chemicals are worse,” lead researcher Zachariah Hildenbrand told Inside Climate News. “They’re in water in higher concentrations and more prevalent among the wells. As you get away from the drilling, water quality gets better. There’s no doubt about it.”
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