Clean your soil of oil or heavy metal contamination by planting a tree or seeding a lawn.

Phytoremediation and Bioremediation referred to in an earlier blog are not the best words to start anything you want others to read. But bear with me as the title to the blog is closer to the mark. For many years now the rest of the world has been progressing dramatically in the science of using plants and trees to treat contaminated and polluted sites. I hate to say this but the UK lags behind significantly and whilst the technology is accepted and used in the UK, it is still in it's infancy.NASA recently spend considerable resources into the research of houseplants and just how much they can do in purifying air. The results are staggering, with many of the palm species coming out on top with incredible rates of absorbation for pollutants including: Formaldehyde, Carbon Monoxide, xylene, and benzene. As such stick a Dracaena marginata in every room.The most incredible results have come out of the research into trees and plants when grown on known contaminated sites. Unfortunately it is impossible to link to the pages detailing the comprehensive lists of the species which can actually reduce and degrade pollutants such as Oils and other hydrocarbons, Heavy metals such as arsenic, lead and cadmium, nitrate and other leachates. But I want to list a few species of particular note:Grasses: 2 of our more common species; Lolium perenne ,Ryegrass and Festuca rubra Red Fescue, have both been proven to enhance degradation of hydrocarbons in soil.Trees: Willow species are well known for their ability to uptake leachates at an incredible rate, but they are capable of degrading some of the more unpleasant heavy metals as well, including cadmium. Holly can also 'accumulate' cadmium.Mulberries, (which I personally feel everyone should plant if they can), have phenolic compounds in the roots which assist degrading bacteria to an amazing degree, breaking down many nasty pollutants in the soil.[A wee diversion, but on the same lines as the degrading bacteria, it is possible to buy enzymes, which will effectively eat oil, diesel and petrol spills. I tested this out once after an incident with a DERV Landrover, stupidly pouring it onto tarmac, the enzymes had a field day and to the best of my knowledge are continuing to munch their way along the road in question - check out zebec]Poplars should be grown more in the UK, particularly as due to increased levels of nutrients flowing into our watercourses have caused stupidly high levels of nitrogen, the rate of uptake by a poplar is staggering. Alders will of course do the same.Other key species are: Birch, for degrading pollutants in dry sites, Red Maples, (together with Alders), are fantastic to capture leachates around landfill sites no matter how large, Buffalo Grass and Miscanthus also.We are in the process at the moment of waiting to get clearance from the quangos to accept biomass from trees and plants used for phytoremediation purposes available for waste to energy. Shouldn't be a problem and watch this space. But if there is a green light - imagine being able to remediate pollution and get paid every seven years for the by product.www.paysagedurable.com

In my capacity as an environmental scientist I have carried out a number of desktop land contamination studies. Where land contamination has the potential to be present I have had to put to the local planning authority a remediation proposal. The whole land contamination situation in the uk is in flux as DEFRA (in their infinite wisdom) have replaced the old contamination assessment system with a Soil Guidance Value system. However there are not many SGV's in place at present. The reality is Local Authorities use a wide mix of contamination assessment methods, but err on the side of caution.
Anyway to the real point, I have informally put forward the phytoremediation/bioremediation approach on a number of occasions, the argument falls on deaf ears. The law regarding contamination responsibility, and the lack of skilled planning officers (prepared to think independantely) means that any potential for human contact with contaminants means remove the source.
A recent re-development of a residential plot I dealt with was flagged up as contaminated, the levels were not high or extensive and a few such as nickel were purely phytotoxic (no human threat) in this case only 0.9mg/kg over threshold limit. The Planning Section insisted on the removal of the contaminated topsoil to a hazardous waste landfill. So 38 tonnes of marginally contaminated topsoil to be removed to landfill and replaced by clean tested topsoil - How sustainable is this approach.
If anybody could provide me with any referenced scientific research info on bio/phyto-remediation they have come across I will look into it and see if I can use it to break the source-pathway-receptor link enough to satisfy planning considerations.

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Comments

PRO

Phil Voice March 10, 2009 at 7:02pm

Great post Pip

You might be interested in sunflowers and how they were used to clean up the contamination after the Chernobyl disaster.
PRO

Phil Voice March 10, 2009 at 7:05pm

"Sunflowers were grown using hydroponics to create long root systems. The plants were then transferred to huge floating rafts where the long roots would be dangled into the polluted water. There is evidence that using this method, the Sunflower can extract massive quantities of toxins, including metals such as uranium from deep into the water.

It is believed this method accounted for removing 95% of radiation from polluted water after Chernobyl."
John Honeyman May 4, 2009 at 9:49am

In my capacity as an environmental scientist I have carried out a number of desktop land contamination studies. Where land contamination has the potential to be present I have had to put to the local planning authority a remediation proposal. The whole land contamination situation in the uk is in flux as DEFRA (in their infinite wisdom) have replaced the old contamination assessment system with a Soil Guidance Value system. However there are not many SGV's in place at present. The reality is Local Authorities use a wide mix of contamination assessment methods, but err on the side of caution.
Anyway to the real point, I have informally put forward the phytoremediation/bioremediation approach on a number of occasions, the argument falls on deaf ears. The law regarding contamination responsibility, and the lack of skilled planning officers (prepared to think independantely) means that any potential for human contact with contaminants means remove the source.
A recent re-development of a residential plot I dealt with was flagged up as contaminated, the levels were not high or extensive and a few such as nickel were purely phytotoxic (no human threat) in this case only 0.9mg/kg over threshold limit. The Planning Section insisted on the removal of the contaminated topsoil to a hazardous waste landfill. So 38 tonnes of marginally contaminated topsoil to be removed to landfill and replaced by clean tested topsoil - How sustainable is this approach.
If anybody could provide me with any referenced scientific research info on bio/phyto-remediation they have come across I will look into it and see if I can use it to break the source-pathway-receptor link enough to satisfy planning considerations.