AD-A285 710

PUBLICITY FOR US ARMY CORPSOF ENGINEERS CONTRACTR&D 6872-EN-01, APRIL 1993

IN-SITU DECONTAMINATION OFMETALPOLLUTED SOILS BY

METAL-ACCUMULATOR PLANTS

S.P. McGrathRothamsted Experimental Station

Harpenden, Herts., AL5 2JQ, U.K.

ELECE"OC 1c 8 1994 ;

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Published Papers:

A. J. M. Baker, R. D. Reeves & S. P. McGrath (1991). In situdecontamination ofheavy metal polluted soils using crops ofmetal-accumulating plants - afeasibility study. In: In Situ Bioreclaination: Applications and Investigations"for Hydrocarbon and Contaminated Site Remediation. Ed. by R.E. Hinchee &R.F. Olfenbuttel, pp. 600-605, Butterworth- Heinemann, Boston & London.

IS. P. McGrath, C. M. D. Sidoli, A. J. M. Baker & R. D. Reeves (1993). The potentialfor the use of metal-accumulating plants for the in situ decontamination ofmetal-polluted soils. In: Integrated Soil and Sediment Research: a Basis forProper Protection, [Proceedings of the European Conference on IntegratedResearch for Soil and Sediment Protection and Remediation, (EUROSOL),MECC Maastricht, The Netherlands, 6-12 September 1992] Ed. by H. J. P.Eijsackers & T. Hamers, pp. 673-676, Kluwer Academic Publishers, Dordrecht.

A. J. M. Baker, S. P. McGrath, C. M. D. Sidoli & R. D. Reeves (1993). Thepossibility of in situ heavy metal decontamination of polluted soils using cropsof metal-accumulating plants. Resources, Conservation and Recycling (inpress).

I Conference Papers, Abstracts, etc.:

A. J. M. Baker, R. D. Reeves & S. P. McGrath (1989). Plant accumulators of nickeland zinc - ecological curiosities or potential deconLaminators of metal-pollutedsoils? Abstract. Paper delivered to the 7th European Meeting of theSociety for Environmental Geochemistry and Health, Royal Holloway andBedford New College, Egham, 11-14 April 1989.

IA. J. M. Baker, R. D. Reeves & S. P. McGrath (1990). The potential for use ofmetal-accumulating plants in the decontamination of soils polluted by heavymetals. In: Abstracts of the International Conference on Metals in Soils,Waters, Plants and Animals, Orlando, Florida, USA, 30 April-3 May 1990.Abstract 188, Savannah River Ecology Laboratory, Universtiy of Georgia,USA.

I A. J. M. Baker (1990). Decontamination of metal-polluted soils. Reflections, 1, July1990, p. 4, AERC Ltd, Colchester, Essex.

IA. J. M. Baker, S. P. McGrath & R. D. Reeves (1991). In situ decontamination ofheavy metal polluted soils using crops of metal- accumulating plants - afeasibility study. In: Abstracts of the International Symposium on In Situ andOn-Site Bioreclamation, (Session 7-A Inorganics), 19-21 March 1991, SanDiego, California.

S. P. McGrath, A. J. M. Baker & R. D. Reeves (1991.). The possibility of in situheavy metal decontamination of polluted soils Using crops of

, metal-accumulating plants. Abstract A2-36, Annual Joint Meeting of the

LI_ _ _____

American Society of Agronomy, Crop Science Society of America and the SoilScience Society of America, 29 October- 1 November 1991, Denver, Colorado,USA.

A. J. M. Baker, S. P. McGrath, C. Sidoli & R. D. Reeves (1992). Th. potential forthe use of metal-accumilating plants for the in situ decontamnination ofmetal-polluted soils. Extended Abstract. In. Preprints of the InternationalSymposium on Soil Decontamination Using Biological Processes, Karlsruhe,6-9 December 1992, pp. 205- 209. Dechema, Frankfurt am Main.

A. J. M. Baker, S. P. McGrath, C, Sidoli & R. D. Reeves (1993). In situ remediationof metal-contaminated soils using crops of hyperaccumulator plants: potentialsand future prospects. Extended Abstract. In: Proceedings of the SoilRemediatiou Workshop 1992, Associaiicn Francaise interprofessionelle duCadmium, Paris 24-25 September 1992 (in press).

A. J. M. Baker, S. P. McGrath. C. Sidoli & R. D. Reeves (1993). The possibility of insitu heavy metal decuntamination of soils using crops of metal-accumulatingplants. In: Abstracts of the International Conference on EnvironmentalBiotechnology in Waste Treatment and Recycling, I-long Kong, 12-14 January1993, p. 26.

A. J. M. Baker, S. P. McGrath & R. D. Reeves (1993). In situ phytoremediation ofmetal-contaminated soils: potentials and future prospects. Paper delivered tothe International Conference of the Society for Environmental Geochemistryand Health, New Orleans, USA, 25-27July 1993. Abstracts, p. 9.

S. P. McGrath, C. M. D. Sidoli, A. J. M. Baker & R. D. Reeves (1993). Plants cleanup soils. Abstract, Paper presented to the 'British Association Meeting,University of Keele, Staffs., UK, 30 August 1993.

A. J. M. Baker, S. P. McGrath & R. D. Reeves (1993). In situ bioremediation ofmetal-contaminated soils using crops of hyperaccumulator plants: potentialsand future prospects for a developing technology. In: Abstracts of the SecondInternational Conference on the Biogeochemistry of Trace Elements, Taipei,Taiwan, Republic of China, 5-10 September 1993. Abstract 55, p. 28.

A. J. M. Baker, S. P. McGrath & R. D. Reeves (1993). In situ biorernediation ofmetal-contaminated soils using crops of hyperaccumulator plants: potentialsand future prospects for a developing technology. In: Agricultural andEnvironmental Biotechnology: Biodiagnosis, Biocontrols, Bioprocesses.Abstracts of the International Conference, 15-17 September 1993, Torino, Italy.p. 168. Edizione MAF Servizi, Torino. LAcceston Foi,'

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I 15 September 1993 British Satellite News (Rothamsted Greenhouses)

11 October 1993 Anglia TV (at Woburn Experimental Plots andRothamsted Laboratories)

I Radio Interviews (SP McGrath),

9 August 1992 BBC World Service, Science in Action

28 August 1992 BBC World Service, Global Concerns

I 23 July 1993 BBC Greater London Radio, interview

I10 August 1993 German Radio

29 August 1993 BBC World Service

I 30 August 1993 Radio Stoke, Country Progranune

I 20 September 1993 BBC Radio 2, John Dunn Show

1993 BBC TV, 'Tomorrow's World'I -!III

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May 1992 Calendar News, Yorkshire Television[Gang Mines, Derbys; Labs. University]

25 June 1993 Newsround, BBC TV[Gang Mines, Derbys]

15 July 1993 Film Unit, Central Office of Information[Gang Mines, Derbys; Labs. University]

Radio IhtreLews/Pirogammes

18 May 1993 Radio Sheffield, live

I 19 May 1993 LBC Newstalk, 18.45, live

19 May 1993 LBC 20.45, live

4 & 6 June 199-3 BBC Radio 4, Nat,:,al History Programme

I 7 June 1993 BBC Radio 4, 'You and Yours'

1993 BBC TV, 'Tomorrow's World'

199,3/94 Transatlantic Films. Filming over next two years for'Plant Hunters' series on Discovery Cbannel

I

III,

Remediotion technologiesVarious sitratcgies exist worldwide,although in the UK remediation tech-nology is a very young industry. BarryEllis of Celtic Tehnologies has out-lined some basic approaches:* containment - synthetic liners,modified clk,•y liners, jet growting, slur-r -walls, grouna freezing* reduction of contaminant mobility- stabilisation and solidification* contaminant removal - vacuumextraction, air stripping* biological destruction -- landspreading, composting and treatmentbed destruction0 physical removal in situ - soilflushing* physical removal ex situ - soilwashing0 physical removal on-site - pumpand treat* high temperature oxidisation -thermal processing

It has to be remembered that remedi-ation technologies are developing allthe time and as the market grows thecost of remediation could fall.Rothamsted Experimental Station(part of the Agricultural and FoodRescarcl. Council) is developing a lowtech solution based on plants absorbingheavy metals within one metre of thetopsoil. Scientists have had succcsswith plants from thte cabbage family

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The Hindu.September 1992

Decontaminatingsoil by plantsý',

The worlds first field experiment to lest thepotential of special plants to decontaminate pc.luted land is now under way in the U.K.

A team of scentists at the U.K. Agricuttural'and Food Research Council's (AFRC) Rothamst-ed Exrimental Station at Harpenden. near Lon-

d, h succeeded in developing plants thatcan grow in soil highly contaminated with heavymetals. Their experiments indicate that the plantscan abso(b the heavy metals from the soil, event.ually leading to decontamination. It is likely thatthis research will lead to a safe, natural and cost.effective method for dealin• with the problem ofsoil contamination.

Heavy metals such as zinc, cadmium and cop.per. which are presment in sewage sludge. canhave disastrous effect~s on the soil microbi(alpopulation in treated farmland,

Over the past few years it Nn been found thateven small concentrations of metals from sew-age sludge applied to agricultural land can sri-I ~ously lnerfnr with soIl microbkological activity.Flhzouv bpaumrw~~e bilvoei Nfo/P. the nitrogen-fixing b tt Infects clover room

Wlct"Y lt~ty 6en . "In expeimental piots of land contaminated

wit, metal only one strain of soll bug was toler-Will to Metals but unalbl to ftx nftrogeri wit Om•ncrnml host. Scientiest inolved in time expri-itl kx •od to estabish which ofseveral different metals was respovnable for thedeath of effech"• smW• of micro ..

two of zinc, cadmkum, copper and nkel wereadded separately to Wi trom the un•ontan•-oimbed contnA plot of the experiment, The resultsshowed that adding zinc-at 1 3 tie fte U.K.

IMt for this element in sudge-feated sod. orcadmnt n at 2.4 times the limit caused cowletedeath of effectUve sirains of microbe within 18montht Copper at 1.7 times tie limit decreasedthe number of deaths but did not cause completeelimination, and nickel had no effect.Most plants at best cao only reove smallquantitie of toxic metals from sod. the pres-ent work has given new hope because the teamhas found that omne specialised plants, knownai hyper-accumulatoms, can absorb much largerconcentrations of" metals.

it has been shown that hyper-accumulatorscan absorb 10.000 mg zinc for every one-tenth ofa kilogramme of dry matter, compared to about30 mg in normal plants. In the case of cadmium,th ey ca l•~ 0() m g p e o nle-tenth of -a

kilogramme of soil compared with the usual onemilligramme. - LPSI,

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~,Alm Baker. a senior lecturer in~J1D cbbaes *~'bbnbe. f'Sh".ffeld's aramal and plant

WVdeploye= to mop up Brit- Isciences department. said theain's abVandned industrial two-year experimneat hadsites.. after the success of an in- proved a theory developed overvestogatlOn into their powers of; favouriteudy

-absorbing toxic sludge. Wild cabbages, which iml .de3 versity and the Governmxnenr rockery plant slyssum. have de-Rothamate eprmental lab- veloped an ability to adapt to

ca re 7fii 'e iv6 a ne' - them harmlessly Into shootstr msigietallic poisons thtan and tissues. Their appetite ap-

current detoxifying techniques, pears to extend beyond metalsIThe successful trials are to municipal rubbish and con-likely to see tihe Wae yellow tarninated sewage sludge.bkow-is of wild cabbage jm'n Dr Raker said yestazday: "Apurple b~uddleia and pink very sMAll number of species1-willow herb as a part of the go further and actlveiy seek outIuner city landscape. toidma to takea up. possibly as st

There am. also hopes that defence mechanism faianzt"cabageclazug"could speed prdators." These vegtaeme

the renaissance of abandoned mocal-etectors will be at thesite-s lto areas from London to centra of the project's nex

or nickel traces- IU qL nA l- 3The cabag trals, funded by to tackle sites currenty aban-

Du Afnt. the US chemical firm, pensively by vdduigonaeue3 range of relatively saturation thgLp cls

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HEMICALS & SPECIALTIES

(Pasty toxins tempt green gourmetslants will be genetically had been burnt and even oldengieered to clean up the smelter sites dating from thetoxic compounds which " American Revolutionary and

cont-aminate large areas of soil 4Civil Wars.in industrial countries. f" -Of the plants we have an-Irojects being carried out and '~a ' - ~significant abilities to accumu-uppurted by DuPont. late lead: hemp dogbane and

"Metal-eating' plants derived k- -. " - common ragweed,' he said.from rare wild relatives of corn- -) b *'Their lead accumulation abil-

inon or garden plants, such as -_ . E ities are not consistent in every~abbage, cress, turnip and rag- soil. Moat metals - and lead in

lieed. will remove pollutants I , ' dA+ r cm ",bJsoil. particular - have numerous=rom and lestore them to pro-- forms, not all of which are equal-

ductive use. V04'P' "C- 4, '. r ly available for plant uptake.In DuPont's central research 'Our ultimate aim is to clone

nd development division at . genes into the plants.'1Glasgow, Newark, USA, Dr Scott -I. . . The stakes are high: in the US

Cunningham and his colleagues alone- the estimated cost of

are two years into a programme , . ." cleaning up hazardous waste islooking particularly at lead-con- j-;-- s','. - $752 billion over the next 30

years. Other parts of the worldAt Sheffield University's ani- -have similar problems and there

mal and plant sciences derart- -. _ -o/ is even hope of developingment in England, Dr Alan . .a plants which could clean up theBaker's search for plants which i' radioactive debris of the Cher-

1have evolved a natural resis- S' 1'nobyl nuclear disaster.tance to metals is funded by It has even been suggestedDuPont. Dr Baker has been that bio-mining could get rid ofstudying metal resistance in conventional mining completelyplants for more than 20 years. by planting metal-bearing crops,

'Some plants actively bio- the earth. menters at the time, the treated 'We are looking towards harvesting them, and smeltingaccumulate metals and detoxify Dr Baker has travelled the sludge they spread annually and geneticaily engineering a model them to lecovel the metal.them internally,' he said. world in pursuit of these plants ploughed into the soil for 20 plant which will be able to deal 'The potential uses of plants

'A considerable percentage of known as 'hypersccumsulators'. years was contaminated, with more than one metal,' which absorb toxins are numer-the plant's weight can be made He found a tree in New Cale- The soal, when Dr Baker came added Dr Baker. ous,' says Scott, who is about toof metal. Some of the xmnc-sccu- donia, for example, which had to use it, was a perfect me- 'Such a plant could have the start work with Conoco in Poncamulting plants are virtually gal- accumulated so much nickel - tal cocktail for testing nine potentil to clean up a site with- City to look at pla.its whichvanised.' up to 2$ per cent of the plant's promising accumulator species. in six to eight years.' might clean up oily sludge. A

The brassica family, which latex - that if the bark is cut it 'Most of the plants are peren- Dr Cunningham's work for species of Bermuda grass isincludes the wild cabbage, bleeds blue sap. nials, including relatives of the DuPont concentrates on lead already known to grow on andradish, shepherd's purse, cress, Dr Baker built up a seed bank popular garden plant alysstm because the company is com- help clean up oily sludge.Iol seed rape and turnip, are par- of green metal detectors and exclusively found on a few mitted to cleaning up sites con- It is early days yet but hopesticularly adept at rsetal accu- tested them on an ideal site at Greek islands,' :.aid Dr Baker. taminated many years ago when are high that current researchmulation. It is not the familiar Woburn in the UK, uadvertent- Accumulator plants are normal- they produced lead-based piod' will eventually allow scientistsstrains which are creating inter- ly created by an experimental ly best at dealing with one spe- ucts and explosives. Scott has to send in the clones and makeest, however, but relatively rare crop growing project which cific metal, although most also been investigating many old for- the solution to the major prob-adaptations only found in areas ended 30 years ago. take up other metals to a lesser mer DuPont sites, as well as lem of contamincted industrialI where metals occur naturally in Unknown to those experi- degree. land where lead lined buildings land a truly green one.

... while busy bacteria help clean-up our actA DuPont team has developed tech- an anp'robic - oxygen-free - environ- has been added to DuPont's waste and mixed with wood chips to form

ninology that uses natural soft bac- ment in which naturally occurring bac- reduction arsenal, compost.m ..L.Lteria to clean up groundwater and teria use the contaminants as an oxygen Reduce, Reuse and Recycle have been 'We'll speed up the natural compost-soil contaminated with chlorinated substitute. joined by 'Rot', with bacteria and other ing process by providing optimal grow-hydrocarbons, solving a major environ- Anaerobic bioreinediation is faster micro-organisms being enlisted to help ing conditions, namely air and water atmental and public health challenge. and more cost-effective than other make sure that an important new the right temperatures,' explained Deb

Chlorinated solvents, also known as methods, such as the commonly used DuPont plant meets environmental tar- Luper of Engineering's Water and Wastechlorinated hydrocarbons, are one of 'Dump and treat' technology, gets. Management Greup.the most common pollutants in ground- It has previously been used success- In DuPont's first large scale waste Initially, the plan was to burn thewater worldwide, fully to treat gasoline and petrol but composting operation, the natural excess microbes from the waste water

They are often by-products of manu- never with chlorinated hydrocarbons, peocess of plant decay will not only help treatment process. It is estimated thatfacturing operations and are used in which are extremely hard to break to treat wastes at the adipic acid plant composting will cost several million dol-dry-cleairng fluids, metal finishing and down. in Singapore, but create a product ben- lars less than incineration, while creat-electronic circuit fluids. The team, which includes Conoco and eficial to the environment. ing a beneficial product.

For the first time, bioremediation has DuPont representatives, demonstrated When the plant starts up in 1994, Once the safety of this is verified byremoved chlorinated hydrocarbons thor- the technology at DuPont's Victoria, organic wastes from the manufacturing DuPont, independent researchers andoughly enough to meet the stringent Texas site and is now testing the process will be fed to bacteria and other government agencies, it will be used toEnvironmental Protection Agency's method to determine how broadly this micro-organisms. decrease erosion and promote lush veg-drinking water standards, technology can be applied. As these organisms feed, grow and etation at the sandy Singapore site, and

The technology involves establishing In another development, a fourth 'R' multiply, they'll be periodically removed marketed in neighbouring countries.

12 Conoco World, June 1993

IUI

II 'Green' solutions to heavy metal pollution7T6 &teV. f) J r-m Cn _ _ _ _ _ _ _ _ _ _

I W~drelatives of the cabbage couldsoon be used to help clean up Britain's

S swcontaminated industrial sites, following thesuccess of a two-year trial conducted by aresearch team headed by Dr Alan Baker inthe Department of Animal and PlantSciences.

The project, carried out in collaborationwith Dr Steve McGrath (a former BSc andPhD graduate of this University) at theAgriculture and Food Research Council'sRothamsted Experimental Station inHertfordshire, has demonstrated that certainplants can be effective in removingpotentially toxic heavy metals such as zinc,

I cadmium, lead and nickel from pollutedland. A settling pond receiving effluents from China's second largest zinc mine at Shaoguan,

The 'green remediation' process they Guingdong Province, has been planted with dense stands of the teedmace Typhalatifolia to remove contaminant heavy metals from the effluent waters and thenare develoI •ing could ultimately prove a less immobilise them in sediments.

costly alternative to physico-chemical clean-up techniques currently employed in theUSA and the Netherlands. It would also Fundamental aspects of the mechanistas Another 'green technology' projecthave the advantage of retaining the of metal accumulation by such plants are underway in the Department of Animal ancbiological integrity of the soil rather than currently being investigated by Plant Sciences involves the use of fast-producing a sterile growth medium which Dr Baker and his research group. Some of growing, productive wetland plants - likegenerally results from present treatment the plants can scavenge metals from low soil the reedmace and common reed - to cleanoptions. concentrations, actively accumulating them metal-polluthd effluents from mining and

Funded by the EC atnd the American in their shoots to similar concentrations as mineral processing works.

chemical finn DuPont, the plant trials have those found in plants growing naturally on

used a range of relatively uncommon metal- the most metal-enriched soils. Dr Baker's Dr Baker and a research student,

accumulating species from the UK, Belgium group are investigating the possible role that Mr Zbihong Ye, are collaborating with

and Greece. These unusual plants, with a the accumulated metals may play as a research groups at Baptist College, Hong

capacity to bioaccumulate several percent of deterrent to herbivory and in contrrl of Kong, and Zhongshan University,

metals in their shoots, have been identified pathogens. Guangzhou, PR China, in a project on the r(

by Dr Baker during research over the last Commenting on the project, Dr Baker of wetland plawmts in metal immobilization ii

twenty years. Whilst in the cabbage family, said: "We have proof of concept - what we both natural and constructed wetlands. Thethe nearest domesticated relatives of the now need is a major development study, using materials from both Europe ant

plants being tested are the cresses and the programme to breed and improve the most China, aims to elucidate the mechanisms

common rockery plant, alyssum. All are promising species and to generate sufficient involved, and to allow selection of

, native to soils naturally rich in heavy metals, materials so that this technology can be particularly useful strains of wetland plantsoften in areas of major mining operations, tested on a practical scale." for further development.

Liverpool Echo Tuesday, June 29, L993

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In Britain

aweadowe

Wto evltl1s

Atprset.th~=I no satlsact'y. way ofgetng rid of the meftas Wtthlot damgn the

Howe".r research has shown thW some*weeds absorb 100 to 200 times hiOhe levels of,metals thm ot6W vejet

An ItIeivdcu drbedha ffs s th n uey grow. ~asIHe~vgmd. ftyScould then be cut. up,dre

Dr '= c*G~th~o theInstitute of Amable.

Cropd eerhIntIrfrsht asta thewodsan mvi It.

before teprocess I nueHowever, fth actual dean-up could be a slow

prcs:one experiment with sewage sludlgo= nneee crop of weed.out say Dr rath: "It would be psil

to~~~ ~wcosyear you grow oneftoseetn an9 reigtems fiinAndseecin ad upI the p KWeffien

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IOI __- i'0D0WASTES MANAGEMENT

-'Northampton-

I Wild cabbageand contamination

Wild cabbages maybe used tocleanup abandoned industrial sites fol-lowing an investigation into theirability to absorb toxic waste, ac-cording to a recent i'eport in TheGuardian.

Scientists from Sheffield Uni-versity and the Government'sRothamsted experimental labora-tories have found the cabbages canbe even more effective at iteutral-ising metallic poisons than currentdetoxifying techniques.

The trials have been funded byUS chemical company Du Pontand the EC.

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I)II

Earth AlmanacI an advantage by storing them in

! their leaves too. That way they mayavoid being eaten by bugs or infect.

~ed by a fungus." It the researchers

can increase a weed's lead intake toS~one percent of its mass, the plants

could be cut, dried, an, burned toreclaim and recycle the lead.

Tiny Desert Fox MustBe Wily to Survive

if presents a host of hazards forthe cat-size San Joaquin kitfox. Of this endangered sub-

species only about 5,000 remain.Their southern California neighbors

GAELR.OO. MUT PICTV0IS

The Future Is Now for a sycamores are measured by scien-tists, who also monitor caterpilars

Global-warming Test-- ~ ~~~~~~and aphids that feed on the vegeta- ---- k-•'-"

ow will plants adapt to the tion. "Some plants may adapt bySgreenhouse effect -rising growing quicker and bigger. Others

H temperatures and carbon may slow down," says project leaderdioxide levels, the wages of fossil Trevor Ashenden.fuel burning and deforestation? Tostudy the effects of such climate Contaminated Soil: Canchange, British scientists quite Plants Get the Lead Out?sensibly are using greenhouses--I eight very sophisticated greenhouses or 30 years an E. 1. du Pont de(colored by creative photography) Nemours & Co. plant incalled Solardomes. F Deepwater, New Jersey,

Built on the coast of Wales by made tetraethyl lead, a gasolinethe Institute of Terrestrial Ecology, additive that was phased out in thethe domes create conditions pre- 198Me. High concentr~tions of leaddicted for the late 21st century. now contaminate 25 acres. Yet inTheir air contains twice today's car- this wasteland, two weeds-corn-bon dioxide and is 5.47 warmer mon ragweed and hemp dogbane-than outside air. Growing in the not only grow but thrive, even asdomes, grasses and small oaks and lead accumulates in their tissues. So

company research- VULM UAIoIS MUVnTC 3. Mc,,•,Ir pIT

era (left, from left include coyotes and golden eagles,

to right) Scott Cun- which prey on them. A bullying out-ningham, Steve sider, the red fox, is invading theirGermani, and Bill territory. Agriculture has gobbledBerti have planted up more than 90 percent of the kitmore of the weeds foxes' former range, virtually re-to see if th•'and stricting them to the Carrizo Plain,other plants can a 400-square-mile basin of grass-draw significant land and scrub. And that shrunkenamounts of heavy habitat can be seawed by drought.metals from con- But the foxes have friends. Thetaminated soils, a Nature Conservancy has bought atechnique called 23,000-acre ranch, expanding theplant remedialtion. Carrizo Plain Natural Area to

"All plants store 200,000 acres, which the groupsome metals in manages in cooperation with thetheir roots," says state and the U. S. Bureau ofScott, "but a few Land Management.

T have likely gained -- JOHN L. Eur

National Geographic, August 1993

Pal w"'Oppwor rocks-heavy metaJgi~~uists z&D a te sovyeaiuaz avidh- as Ch~ae i the'eur ofdouda =atomed w oflld tefamb

h~ao~woc*i,#ols~diitir. d Vtil dot s rý A! mdlv _ -w evenr that hur-

C of tai=Cdnvirrmental pol- . dkia, coa lm@ taid -4cld amoida cmn @wt.ado" mejmm I k ba"n m I h ftd -f*C be' ~oft tor Wind roe d@.0 30rf c hrovet'm~~ao -,ii~ thS. r *la could be at k* a astar tual and horticultural tmm gtbor &rethar pI~

be S"md e Qfidd Alk -,~ - dr P-011116 Sti- Fs decatasmiation that doesn't Together - dlih .o athe.U- Onecowlbmwto~ylbejllat ~IOW W~ U- ote h at R ad's buti n.*, aD binologicaWciiynq the P00 Stay metals lost a Wdutuul or other~mo~ak~aiw.In -two of Antic Crop& Reserch &m ~towl. Itcould= =eafoth a to i wme. when the , asm are

myP dofrkladmnd cobtmsAd Nod plaits frm the - - and vap ýla umug a trl re eeypalistmd sites. bmwea and incierted, thedb IM~hnffift10- pposc totun te de- Touh ee f naoticie tofD~ nAwd wh c conain

*ir~~~~~~~~~~~d.~~w~ It wol mayev nod decide toe tr metals.e u o ha ~c t--m

of som em metals suha ck mm lmaaa site. at the bgm-mrinally polluthat han only r j. or mysieK= = Though this is unflkely to bemaziall poated an muns l th' a ,,wobl Me it mayxdie, cbmiu amid aithi, ammd rumeuchcmsre. would be a cheap, wimually plant could be wome a IIOOr so m swuay. age

ouald be the &*am ing bar h-W 'Ye &mo ostPh"t o lo way of redclaiming land cosilanw. deltd n mua Osam@i mature to ftitbck sod tha uproatad ShXm and hai 1.a -oh iduatmy. - In therwairmhyuco- oinm gw biiyC-lils polhudol.. I . em thety'wmr pit- 7i b murea h h com daftadod -dbqmd e mmethem. the bhal.

litha dow. lo w~thadhii 1111 dw SOl Whet we bech~ r aing ccbkg wl mo 1111111. we 8"

tba so h Q* PH=tion soca Belte hme.bmaauao besdhein~ asuweplady 2 for othe mm

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I Metalfwssende Pflanzen entgfieftenfoden.,Hyperkkumnulatoren" nehmen groB. Mengen an Scnwermetallen auf / RIlckgewinnung

IPflanzen gedeihen auf claem FedKohiarten. Nicht in Promille, son- Schon nach zebn Emnten babe sich-des Institutes fur Ackerbail und Ge- dern in Prozenten ilires Eigenge- der Anteil an Schwerxnetallen in ei-

treldekunde in Rothainsted bef wichtes ziehen sie Schwermetalle ncr Industriebrache auf Iandwirt-London. aus demn Boden und speichemn sie, so 3c6aftich akzeptable Werte gesenkt.

,.Hyperakkumulatoren' hat sic der McGrath. Er hofft daB -1ch nach der Der Boden war nut Kupfer, Cad-IBiologic-Professor Steve McGrath Ernte aus der Pflanzenzische, die zu miLm, -Nickel, Chrom und Blei ver-wegen ihrer metallspeichernden Ei- 29 Prozent aus Metalloxiden bisteht. seucht gewesen. Eine besonderegenschaften getauft. Hunderte von Metalle wiedergewinnen lassen. Vorliebe haben die Pflinzchen fuirSorten gibt es, unter ihnen das Alpi- Erste Versuchsergebnisse stirn- Cadmium und Zinik cntwickelt.

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Pflanzen ziehenIZink und Bici aus Welcher bioloishen Eigen-verseuchten Bbden ihren HurPger atif Metaillverdan-

ken, wwzsen die Forscher nochdpa/ok London - Metalifressen- nicht. DaS sic es tin, ist aber alsI de Pflanzen gedeihen auf einem botanische Kutiositat seit lan-Feld des instituts fir Ackerbau gem bekannt. Metallophythenund Getreidekunde in Rotham- hei~en diese Pflanzen. Sie wach-sted bei London. ,Hyperakku- sen meist auf Schutthalden vonImulatoren" hat sic der Biologie Bergwerken. Zuni Beispiel dasprofessor Steve McGrath wegen Voralpen-Hellerkraut (Thaspiihrer metallspeichernden Eigen- alpestre). Es bevorzugt zinkrei-schaften getauft: Hunderte von che Standorte. Mit 100 MiUl-Sorten, darunter das Alpm'e grammn Zink pro Liter gedeiht esPfennigkraut und verschiniene normal, mit 500 blifiht es. AndereKoblarten. In Prozenten ihrer P0flncn k~nnen bei dismmEigenrgewichtes, so McGrath, Zinkgehalt nicht gedeihen so

zeen sic Schwermetaile aus muB da= Kraut keine Konkur-demn Boden und upeiclaern sic rena tflrciten. M~lcherweisezum gra~ter Teil in ibren BuIt- dient darn aufgenommnien Metalltern Er hoift daO sich nach der auch dem Selbstschutz, indemnErnte aus der Pflanznashe, die es fleren den Appetit verdirbt.zu 20 Prozent aus Metalloxide Erat einmal konventionelIbesteht, Metalle wiedergewin- due Aus ud4uct inen lassen. McGrrath die meafesnen

Erste Versuchzergebnise Talente aelme .Hypemkkuamu-I I stimmen jim sebi, uehr optimi- l.torcn* verbeuaern Soilten diesatisc Schon nach sehu Ernten Pbra~her m mit iditeln derhabe sich der Anteff an Schwer- Gentechnologle. ptmietxi -metallen in einer Industriebra- wow' auch in Ezgad ein Ge-che auf Iandwirtachaftich ak- nehmigwUngvrftah= ntig imtzeptable Werte geuenkt Der BO- -, darn mO~te''zichergestelltden war mit Kupfer Cadmium, werden, dW aich die metaflfresNickel, Chrom unci Blel ;;r-' senden Pftlnwi zilcht unkon-Iseucht gewesen. -Elne besondere uafliert vermehren. Eine Sa-Vorliebe haben die Pfiaznzen fidr menmischwtg geger. Schwer-Cadmium und Zink entwickelt metaffie mO~te sich in ibere Ap-,.Zink kann ich ihnen auf unse- Petit aid metaffische B~den be-Irem Boden aber leider nicht an- sbrlinken.NOWen bcdauert McGrath.

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Financial Times Tuesday August 31, 1993

* Cean-up crops.* tes~ted for work.1on toxi Soils

PLANT * Whi tae,. up toIL, Mcoratb. u~iiests 'that p015131tmetalas nutrients- ~m be coul be genetically engineered

forrecycmtzg. to -eelswherthe metalsProfessor Steven. Mc~ath of could be harvested economi-

the Agrk.4lturai and Food cally.Reseattch Comdas Insttute of .Du Pont. the internationalArable .Crops .Research chemical company,- Is linter-decie th xeietletdInuigtetcnqet

proms -cad smea remd~r clean p la otmntotics,- thee hig rno l additv tetorla we-thy t-

-His research tuami has tested was produced, and a nmetnga number -of plants for zinic mapany plans a test to pouptake on'soils pollute by duce pure metals from hair-licsy metals from- London vested material.sewage ovar 2D yesis. Plants which have the aIlitHThe most efficient Plant, to andletoxic metal are

z~ oacceptable Uesatrtce rfM~ahadnine cnopplngL Prof McGrath Owe of Wh chatopion naturalsaid this could be achieved In accumulators is Sebertia aen-three years using intensive minhta, a tree that lives -oncultivation. nickel-rich soULs *An obvious

Existing metbods of physical application would be to 'tapIand chemical treatient to such trees for nickel, In anremove -soil pollution are analogous way to that forexpensive and also alter the rubber." Prof McGrath saidsoil.'struicture, - leaving It green remedlation could -beIunsuitable for cultivation. combined with bloremedlatlon,.

Using green remedlation the technique in which bac-techniques, a hectare of con- teria ameused to break downtaminated soil could be cleaned organic pollutants such as pea-up for L5,000, leaving it fertile, tickiesto produce a one-stagewhereas conventional treat- clean-up.ment by vitrification costs He said he would also like to£18,000 per hectare. study plants in areas where

At present. the potential of there is a high level of radioac-Ithe technique is limited by the tivity, to see if they accumu-productivity of the plants. Prof lated radioactive materials.

The Guardian, Tuesday August 31, 1993

I~.I bb ue 'king' intacklW moisons

i ~ ~ w-" SOm' b . far. VAoft 35%0000_____ _____ ____ flowering Plants, scientists

have d-Wvv"er~dnal 0Cot hem'v IN' Vi hWan e ato iet

be racuie thwk fla etaninated by miak on

U ~~r~all xkn C ~trmeiUfsis ih si~ojy ~dnns .u dI~they qbe

Even lthe un 11waI as TIbauid.

mtephen McGrathtodheateMrA opzmw4I aseodatlypl-98a eadng. Oaao n por hdareinBat a rbni of wed sf#And ameunlnhmvift

aebaheen found-which -It wouI4 do av~uoJaluise n a=l cohskt. an tin, but whtw- ol

tninecSdIwn adto knw Is, car~ it do cther met-

Rothainsted Ixperimental The plant could- be' gmnei-a

StaIoniu cas tareiti r ieycale ywod thi thke uhapi fal

dle the metals in it js is al-ter, cepecially if encouraged bi

Iiimcn r eyldmnm

The Independent, Tuesday August 31, 1993

I Pl~ants suk metl>~~o~~oflted IancE

mcmii ot o tillued allmidSUSAN WiAtII

icduhn4m d Bu s zsaotund 3,00(1 tina of uwkqa-abandoned suidda nno mntdsi per hectare Th

wages 6Ci be grmd p ams of iaih with cean-~a

'kavng da, frtu WiStMUt"Os daupc pant. Maugf hisOci?

thO~spedmThehzm =notd with lead-

4mbe U perocvat ini~dhi Ut -hsl.ofkd h onad, With.04&in be piwsP& . .11o ftesits. ame old imi:tnnt for nitdu - taa sicWtheved" Cdte)a

u~f i nbim %=kW a hI of vanel whidame MM oftopan do wn an biM and m~amW*

off a -polluted site produces -Dr Mc~inth said .' ...Dr Mdcrath' team tested 10.'

~r sc utinyplantspecks on a sitt coontamiIrs i ti ywt 20 yw wm*l of.Landon sludgeand remuded the

"-what are the insurane comn- ukeup of metal such an inc,

paic=oigto do'[, you hae copper.,Lmawngae adCm

taeyormortgage pectancy that three specks - a dowMe a-through?'tive Oi~valsum, an flpine Penny

Professo Eano said there was ames and northern rock cess. -an urgicut need for a debate on had an unusually larg caPIcitYI the ethical mind social conse- for storing metalquence oflan inamd lifepn He is confident that the w4,l

"ltitimy tothikaoutts funded in part'bydie US Amy,that we don't get taken by star- should produce a tdxeper Way to.pwzre if scientific dreams become deal with polluted land than any;

reality." of today's appioaclnes.

Ii Dally Telegraph, 4th October 1993

I

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clt>.ceeaner by cabbageI PLANTS from the cabbage cadmium and nickel '1i'ialsfamily could clean land con-. haye been funded by the EC,taminated with toxic wastes, Leverhulme Trust and thesays Prof Stephen McGrath -US anmy to deconta 'minate aI of the .PRothamsted Experi- -.field treated with metal-con-I mental Station, Harpenden. taminated sludge. The~meth-.'The: plants- have proved od could take.-another five

promising at removing zinc, years to devrelop.'.--1:,-. R H

I1II'II

SPlants could cleanI contaminated land

find ontanminaucd usth hiv, nictals timld hi.le.aned by plants vwhich extra'ct Eli nt'-tamninanis

and store them in their aiovc ground portions.'now aacording to a paper prewnted at thie ilritish

M-. A%% tion for (he Advancccllent of Scien-tc (lcrn(c:coi Augus.;.

Ste•se'n Mlc(rath. front the ARFC( InstiUlt ofl Arablc* Crops Research at liarpendcn. ,aid a number of plant,

acted :ias ,h.vpr accumulators. with le-acs cotntaininghigh concentratitons of metal.% such ai cadmitlm.copper. lead. nickel and tine

Plants growing on a contaminated stew could N.croppcd. and the mctal-enriche'd hitmnass eitherdisposed As 12ndfill or reduced ito a-h. which could

allow metal% to be recovered and rccyched

N Professor McGrath said the "greecn remediatisn of"contaminatcd sites would lcave soil in better conditionthan other ectan-up techniques. such as acid-lcaching.electro-osmosis. or vitrification. which remove allhiological activity. and affect the soil structure

Species of plants which act as hvpcr accumulators ,ar%from herbaceous plants to trces. The latex of one irec.Srbertia acuminata frum New (:aledonia. containsmore than I I per cent nickel, which could posihly bec"tapped. as other tree are fir ruhhbr

An experiment was carried out on a field where metal-crontaminated sludge from London had heen applied for20 years. Ten species were grown to test their abilityto remove metals, one of which. Tbleapi caerulescens.reduced the damount of zinc in the soil it an acceptablclevel after just nine croppings. Al.ssum leniunm wouldrcmove the same amount of zinc aftcr 81 croppings.and oilseed rape. by contrast. would require 832

i €eroppings.I PrL-_ofessor McGrath pointed out that hyWr accumulatorplants are relatively rare. And tften grow in remoteareas. Some of the plants arc hard to crop. and newmachincry may have to be developed to colpe withlow.growing or shurt-hived species'We look forward to seeing contaminated andAbandoned sites growing clean with a cover of yellowand while flowers of hyper a•cumulator plants'

More research needs to hie dOne to ide.nify othersuitable species. and tti find ways of increasing theireficiincy as accumulators, he added.

Copies tif Plants 1atm# up oilts can be obtained fromProfemsr Steven Mc(rath. suil Science l)epartnment.fRotthans(ted Experimt'ncal Station. Ilarpe'nden.

flertfordshirc AIA LIQ

* Botanists At Cambridge I niveritv are bIreeding Avarivv ofi clot which hiss treater re'istaoee top luttlhcino tl:ises- tItni the ordinars clii. And which c•iuldt ht

used to replant areas tcsotid oi ihei tree for more thaiaM, NI years Abotut -tt0i sapling, (it die snticioth.hla'vd cnii

Arc being planted artound (imliridg-.hire as a pilot

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. PLANTrS CAN CLEAN UP CONTA•MINATED SOILS"; ZýA.,tl L 1 jI.•, C~."

Zg"Lý:I•.•Jl 4 3,,jJI,t that a smal but growing number are and found only in remote a~reawcapable of accumulating very high con- an urgent need to collect &r

•jJ-I •:JI •. I•,4, ,.-_ centrations of metals in their steins and them, and to establish a

, .. .•, o.• '• ,] ff . ;x.: i •vJ.L leaves, and more tt n 70 species are now facility for their large-scale pr,I~ ~ ~ ~ ~~~; .• ,ýLlO La'l•A.Q .j known to be what are classified as

,•,;•.•,L.• .•, O..•.J •.hyperaccumulators. For further informnadon, pleaseStephen McGraph, AFRC

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Pflanzen zur Entgiftung*kontaminierterB 0do

(BN) Nochdern Wissenschaftler ont- Als ein Beispiel elnes soichon Hyper- schiedener Anoen auspflanzen, staff* ek haben, dlass einige Pflonzonor- akkumulotons nonnte Dr. McGraph der in unseren Versuciten gepflanztentn in der Lago sind, sehr hake Kon- die Sebe rtia ocuminato, die ouf Monokulturen, urn dem Baden dort,

zentrationen von Metallen in ihren nic-kel- und chromreichen BMden in wooas sich urn die Obliche Mehn~ch-I tieten und BIattern zu speichern, ha- Neukaledonien beimnisch ist. Der La- verschrnutzung handelt, rnehrere Mo-ben Si. die Ansicht ge6ussert, doss tex diesos Baumnes enthalt Ober 11% talle gteichzeitig zu ontziehen.i*Pflanzen violleicht zur L6sung des Nickel und ist daher bidulich gefd~rbt.-Problems kontaminierten B-5den bel- Lout Dr. McGraph ware es nur lo- Do Hyperakkurnulatoren nechc ver-trogon kdnnten. gisch, sokcho Baurne analog zur haItnismassig jinbekonnt sind und bis-Ober 70 Anten sind bisher bekannt Gummigewinnung zur Gowinnung her nun in abgetegenon Gebieten go-

und werden als sogenannte tHyper- von Nickel onzuzapfen. funden wurden, sielit Dr. McGraphI Okkurnulatorern* bezeichnet. Di e d iie Notwendigkeit, sie zunachst zuPflonzen, unter denon krautortige bis Mit finanzieller UnterstOtzung der idontifizieren und zu kultivieren undbin zu Baurnen vertreten sind, enthal- Europaischeni Union, des Leverhume otre Knimplasma-Einrichtung fur ibmeten dos 100. bis lO00fache der rObti- Trust und der US-Arm.. habon Wis- Zucht zu granden. In der Zukunft kdn-chen Metallkonzentration in ihren senschaftler ous Grossbritannion und noe man versuchen, die metottspol-I brrice Sprossen. Nouseelond Feldversuche auf oinern chemden Eigenscbcuften mit Hilfe der

Boden durchgefohrt, aid den 20 Jok- Gontechnik iii optimieren, wenn dieDr. Steven McGroph yam Institute of ne long schwennetallbetasteter for die Metollansommiung zustandi-I .Amble Crops Research in Harpenden Schlamm oufgetragen warden war. gen Gene identifiziert seien. Dann

bei London sagte ktirzlich auf oeine Darauf wtrden zehn Pflanzonorten bestehe die M8glichkeit, die entspre-I Konforenz, doss die Entdeckung von ausgepflonzt und ouf lihre Fahigkeit chenden Gene auf lsistungsfahige,immer mebr Hyperokkumulatoren die untersucht, Schwermetolle oufzuneh- aben ungeniessbare WirtspfacnzenPerspektive enbffnet habe, kontami- men. -zu ubentriagen.nierte Wodn und IndustriebrochonI mit einern Teppich weiss- und geibblOi- Dr. McGroph sagte zu don Ergobnis- Dr. Steven McGraplibender Hypeorkkumulator-Pflanzen sen: aDiese Method. zeigt vielver- Institute of Arable Crops Researchzu roinigon. Gegenwartig gibt s kein sprechendle Ansrdtze zur Reinigung Experimental SiafionI Rainigungsverfohren,' dos kostengon- elnen massig belasteten Indlustriebra- Harpenden, Hartsstig ist und die Bodenfentilitat noch cho, wenn man for die Reinigung eini- England Al 5 2JQBeseitigung der Metallbelastung or- go Johre Zeit hot. In Zukunft kann Tol.: 0044-582-763133halt. man vielleicht eine Mischung ver- Fax: 0044-582-7609.81

WASSER BODEN WJfT UMWELTSCNU!z 3/94 1

S I TI .N,\•AlIONAI. PHI:.%-C.•1TIN( Ri4RI..At224-236 Walworlh Road.

London SEI7 IJE

Extract fromFannersn Weekly - London

ARIA MEETING

Sewage sludge cleansed.1 Maintainai.;j soil quality gave

delegates at last week'smeeting of the ArableResearch InstituteAssociation plenty to talkabout. Andrew Blake reports

FARMERS on land polluted byheavy metals, perhaps fromsewage sludge, could eventually beable to clean it up by growing spe-cial crops.

Accordint iý 'ofessor SteveMcGrath RothamatedExperimental -.!on, it mighteven be possib', ecover valu-able metals by p. vassing the har-vested plants.

He points out that the amountof sewage sludge dest ad to end Any heavy metal build-up following sewage slud4p application could be rectified using 'hyper~accumulator*up on farms after 15 ., when it plants which concentrate the metals in their tissues. Offlake may be 300 times higher than normal cropping.may no longer be dumped at sealegally, is likely, to "le. showed that more than 80% of the that other soil micro-organisms are unusually efficient at concen

Control of indus..si4, effluents zinc, cadmium, copper, nickel, could similarly be affected merits a* trating heavy metals in their topshas helped reduce the amount of chromium and lead applied cautious approach. In what Prof McGrath believe.heavy metals like zinc, cadmium between 1942 and 1961 remains in A recent government review on is the world's first field experimenand lead in sludges. But much the cultivated layer. "They are the use of sewage sludge recom- to test the idea, researchers acomes from domestic sources. very persistent and stay in the top- mended that the legal limits be Woburn have discovered somrI Increased recycling of municipal soil." Normal cropping might take tightened. The justification for set- species could absorb up to 30,00(wastes and the use of composts is 2000 year-, to remove them. ting different levels according to parts per million of zinc but sta.likely to add to the burden. Long-term trials have proved soil pH is also due for a rethink, healthy. "A normal plant or

Unlike nitrogen, such metals they could harm nitrogen-fixing A more radical way forward is healthy soil would have abouleach only very slowly, says Prof bacteria associated with white the use of so-called "hyper-accu- 30ppm, and on polluted soiMcGrath. Field tests in 1985 icx ,r, he explains. The possibility mulators". These are plants which 300ppm."

I

I

SPEKIRUM

I Kontamni~erte M~en~ mit PflanzenentgiftenI Vrsehedeneame Flaz.atelasec Als ei Beispiel elne soichen 1W-Ak& sur Dekoataaluaetion von 56- Perakkumulators nannte McGraphdeselmtzueuldle nit Metallen bela- die Sebertia acwnlnatadle autnik-sttladEugl*&eWluueusdaaftkr kel- urid chromreidhen Baden infandem heaus, dal butlante Neukaledonlen henimLidh ist. DerMfanzea Is der Lags dad, Behr khae Latex dieses Baumnes enthit (IberI Koametratioaen von Kotailen In lb. 11I% Nickel end Lst daher bitutich -

rea tleea nd lattern u spet. ge~rbL Laut Mcernph w~re es nurchem. Ober 70 Arten mit entspre- logisch, soiche Bliumie ansaog airdienden Eigenschaften sind bis- Gummigewinnung zur GewinnungI her bekannt und werden ris sage- von Nickel nnzuzapfen.nannte HFyperakkumnulatoren' be- Mit finanzieller Unterstitltung..zeichnet. Die Pflanzen, unter de- der Europiischen Union. des Le- ,.t- -':I nen krautartige bis hin zu Baumrte verhurne TWAutend der US-Arrnee.vertreten sind, enthalten d&~, 100- haben Wissenschaftler aus GroE- clvshednAro yrkioaato w e "vww ebis 1000-faclie der Oblichen Metall- britannrien und Neuseeland Feld-AdtezceemAreHpekkuttu wd.wtsdweeelkonzent-atian in fibren oberi-di- versuche auf einemn Boden durch- knallre oeprelnagplutI schen Trieben. gefiihrt, auf den 20 Jahre lang

Dr. Steven McGraph vam Insti- schwermetallbelasteter Schlanmm Versuchen gepflanzten Monokultu. metallspeichernden Eigensebaf-tute of Arable Crops Research in aufgetragen warden war. Darauf ren, umn dem Boden dart, w3 es ten mit Hilte der Gentedmnik zuop.-Harpenden bei London stellte wurden zehn Pflanzenarten ausge- sich urn die (Ibliche Mekirfadwver- timieren, wenn die f~ir die Metall-kilmlich auf einer Konferenz fest, pflanzt und auf thre Fihigkeit un- schrnutzuipg handelt. mebrere Me- ansarnmniung zusttindigen Gene

dgdie Entdeckuxig von urtmer tersuchtSchwermetaileaufzurneh- talle gleickizeitig zu entziehen.' identifizert seien. Dann besteheS mekir Hyperaklcurulatoren die men. Da Hyperakkumulatoren noch die Mdglchkejt, die entsprechen-Perspektive eroffnet babe, kont~.- Der Wissenschaftler zu den Er- verhatltnismlh~ig unbekannt sind den Gene auf leistungsfkhige, aber

mrdnerte Boden und Industriebra- gebnissen: DEiese Methode zeigt und bisher nur in abgelegenen Ge- ungeniegbare Wirtspflanzen zuI chen mit einemn Tb-ppich weig- und vielversprechende Ansaitze zur bieten gefunden wurdeai, sieNt der ilbertragen.gelbbliihenderHyperakkuxnulator- Reinigung einer magig belasteten. englische Wissernschaftler die Not-Pflaxizen zu reinigen. Gegenw~irtig Industriebrache, wenn man f~r die wendigkeit, sie zualchst zu identi-glibe es kein Reinigungsverfahren, Reinigung einige Jahre Zeit hat. In fizieren und zu kultivieren unddas Witnlch kostengimnstig ist und Zukunft kann man vielleicht eine eine Keimplasrna-Emnrichtung fur

deBodenfertilidit nach Beseiti- M6ischung versdiiedener Arten ikire Zuckit zu griinden. In der Zu-gugder Metailbelastung erbat. auspflanzen statt der in unseren kunft ktinne man versuchen, die

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