Emerging/New TechnologiesEmerging/New Technologies

ENVM 644: New Technologies in Environmental Management

Dr. Robert Beauchamp

PHYTOREMEDIATIONPHYTOREMEDIATION

NEW & UNIQUE

EXPLOITS NATURAL PROPENSITIES OF CERTAIN PLANTS TO REMOVE CONTAMINANTS FROM SOIL/WATER

CAN REMOVE ORGANICS & METALS

NEED A MANAGEMENT GUIDE

PHYTOREMEDIATIONPHYTOREMEDIATION (cont) (cont)

PLANTS CAN METABOLIZE CONTAMINANTS IN SHOOTS

OR

RELEASE CHEMICALS THAT CAN REACT WITH THE CONTAMINANT & DIMINISH THE HAZARD.

OR

INDIRECT EFFECTS – INTERACTIONS BETWEEN ROOTS, MICROBES & SUBSTRATES ENHANCE MICROBE ACTIVITY WHICH CAN DEGRADE CONTAMINANTS (RHIZOREMEDIATION)

DIRECT & INDIRECT PROCESS CAN OCCUR CONCURRENTLY.

MANAGER SHOULD KNOW WHETHERMANAGER SHOULD KNOW WHETHER

UPTAKE & METABOLISM OF CONTAMINANT WILL RESULT IN COMPLETE REMOVAL & DETOX.

OR

A TRANSFORMATION PRODUCT HAS ACCUMULATED IN THE PLANT (CAN BE HAZARDOUS).

OR

WHETHER PLANT-MICROBE INTERACTION IN ROOTS HAS DEGRADED CONTAMINANT IN THE MATRIX.

NATURE OF CONTAMINANT WILL:NATURE OF CONTAMINANT WILL:

DETERMINE PARTITIONING INTO WATER PHASE (SOLUBILITY) OR LIPID PHASE IN A MATRIX (FAT SOLUBILITY). 

LIPOPHILICITY OF A CONTAMINANT CONTROLS ITS AVAILABILITY & TRANSLOCATION IN A PLANT.

MEASURED AS OCTANOL-WATER PARTITION COEF. (KOW).

KOW – RATIO: CONTAMINANT CONC. IN ORGANIC SOLVENT TO ITS

CONC. IN WATER.

LOW KOW = HIGH WATER SOLUBLE COMPOUND

HIGH KOW = HIGH FAT-SOLUBLE COMPOUND

GENERAL RULE:GENERAL RULE:

UPTAKE OF ORGANICS BY PLANT ROOTS INCREASES WITH INCREASING KOW.

FOR TRANSLOCATION – AN OPTIMUM KOW EXISTS.

COMPOUNDS WITH LOW KOW < 10 ARE NOT READILY UPTAKEN BY ROOTS. CAN FLOW AWAY.

IF LOW KOW ENTERS PLANT, ANY TRANSLOCATION IS LIMITED BY LIPID COMPONENTS OF PLANT TISSUES.

HIGH FAT-SOLUBLE COMPOUNDS, KOW >103, HAVE LIMITED DELIVERY TO ROOTS DUE TO LOW WATER SOLUBILITIES & HIGH PARTITIONING TO LIPID PHASES IN THE MATRIX.

COMPOUNDS MOST READILY TAKEN UP AND TRANSLOCATED INTO PLANTS HAVE KOW BETWEEN 10 - 103.

IMPORTANT FOR MANAGER:IMPORTANT FOR MANAGER:

AN OPTIMUM KOW EXISTS FOR TRANSLOCATION OF

ORGANICS.

MANY CHEMICALS & PESTICIDES FALL IN THE RANGE FOR UPTAKE & TRANSLOCATION (KOW 10-103).

PCB’S, HYDROCARBONS, DIOXINS HAVE KOW’s 104-1010.

MOST SUCCESSFUL WHEN FOCUS IS ON STIMULATION OF RHIZOSPHERE BIODEGRADATION INSTEAD OF PROMOTING PLANT UPTAKE & METABOLISM.

PLANT ENZYMESPLANT ENZYMES

CAN CAUSE TRANSFORMATIONS WITHIN THE PLANT.

ENZYMES CAN TRANSFORM CONTAMINANTS OUTSIDE THE PLANT (EXPLANTA).

CAN TRANSFORM MUNITION WASTE (TNT) & ORGANIC DEGREASERS (TCE).

ENHANCED MICROBIAL ACTIVITY IN PLANT RHIZOPHERESENHANCED MICROBIAL ACTIVITY IN PLANT RHIZOPHERES

CAN SPEED UP ANY TRANSFORMATIONS.

NEED SUITABLE PHYSIOCHEMICAL ENVIRONMENTS.

PLANTS ROOT EXUDATES, I.E. CARBOHYDATES & AMINO ACIDS. ENHANCES GROWTH / BIOACTIVITY OF MICROBIAL COMMUNITIES IN SOIL & PROMOTES DEGRADATION.

BIOFILMS ON ROOT SURFACES (PLANT MUCILAGE) PROMOTES DEVELOPMENT OF MICROBES.

MICROBIAL RESPIRATORY ACTIVITY CAN REDUCE O2 CONC. & CREATE REDUCED ENVIRONMENTS. CAN TRANSFORM HIGHLY CHLORINATED COMPOUNDS.

METALS REMEDIATION POTENTIAL METALS REMEDIATION POTENTIAL

SOILS CONTAMINATED BY METALS:– MINING– MANUFACTURING– URBAN ACTIVITIES

CAN DISRUPT ECOSYSTEMS

CAUSE HEALTH PROBLEMS

INJURE PLANTS

CAUSE ANIMAL FATALITIES

LEAD PROBLEM – CHILDREN

METALS REMEDIATION POTENTIAL (cont)METALS REMEDIATION POTENTIAL (cont)

EXAMINED TECHNOLOGIES– EXCAVATION

– ELECTROCHEMICAL

– ENCAPSULATING

– PHYSICAL

METALS ARE NOT BIODEGRADABLE. MICROBIAL PROCESSES OFFER PROMISE. A MICROBIAL PROCESS INVOLVES OXIDATION-REDUCTION

REACTIONS TRANSFORMS METAL SPECIES FROM SOLUBLE, MOBILE AND

MORE TOXIC INTO INSOLUBLE, LESS MOBILE & LESS TOXIC FORM.

THEN SEPARATED BY CHEMICAL/PHYSICAL PROCESS. EX. REDUCTION OF HAZARDOUS, SOLUBLE Cr6+ to

INSOLUBLE, LESS MOBILE & LESS TOXIC Cr3+, AND CHEMICAL PRECIP. AS Cr (OH)3.

HYPERACCUMULATORS: HYPERACCUMULATORS:

CERTAIN PLANTS CAN REMOVE METALS FROM MATRICES BY UPTAKE, TRANSLOCATION, & ACCUMULATION IN SHOOTS.

A HYPERACCUMULATOR CAN YIELD GREATER THAN OR EQUAL TO 0.1 % Cr, Ni, Co OR GREATER THAN 1.0% Zn or Mn IN ABOVE GROUND SHOOTS ON A DRY WEIGHT BASIS.

ECONOMIC VALUE - CAN LEAD TO PHYTOMINING/PHYTOEXTRACTION

SOME PLANTS CAN ACCUMULATE UP TO 1% OF BIOMASS FOR Zn, Ni, Co, Mn, Ar.

HYPERACCUMULATORS: (cont)HYPERACCUMULATORS: (cont)

TREES OFFER ADVANTAGE OF HIGH BIOMASS PRODUCTION.

TREES GENERALLY SLOW GROWING & POTENTIAL FOR LEAF DISPERSION.

GRASSES & CROPS HAVE HIGH GROWTH RATES & SOME HAVE HIGH METAL ACCUMULATION.

WITH LOW BIOMASS PRODUCTION, GRASSES TAKE LONGER TO ACCUMULATE METALS.

CROPS ( HIGH BIOMASS) CAN CREATE A HAZARD TO THE FOOD CHAIN.

HYPERACCUMULATORS: (cont)HYPERACCUMULATORS: (cont)

MOST STUDIED PLANTS ARE:– FAMILY BRASSICACSAE:

– GENERA – BRASSICA & THYLASPI

B. JUNCEA- LEAD, CADMIUM, ZINC

T. CAERULESCENS (ALPINE PENNYCRESS) – ZINC, CADMIUM FAVORED WITH LOWERING THE pH.

LOW GROWTH RATE AND LOW YIELD ARE LIMITING FACTORS.

BIOTECHNOLOGY CAN HELP.

REMOVAL BY PLANT ROOTS REMOVAL BY PLANT ROOTS

RHIZOFILTRATION -  – REMOVES METALS FROM SURFACE & GROUNDWATER

BY:• ABSORPTION• CONCENTRATION• PRECIPTATION

TERRESTRIAL PLANTS ARE BEST: – LONG, FIBROUS ROOTS

– LARGE SURFACE AREA

– EX. CONSTRUCTED WETLANDS SHALLOW LAGOONS GW/WASTE WATER PUMPING

PHYTOSTABILIZATION:PHYTOSTABILIZATION:

INTERIM CONTAINMENT STRATEGY

FOR SITES WITH LOW METAL LEVELS BELOW RISK THRESHOLDS.

LARGE SCALE REMOVAL ACTION NOT FEASIBLE.

PLANTS WITH HIGH TOLERANCE FOR METALS IN SOIL & LOW ACCUMULATION.

VIGOROUSLY GROWING & EXERT HYDRAULIC CONTROL OVER TRANSPORT OF METALS.

MATRIX CONTROLS:MATRIX CONTROLS:

PLANT ESTABLISHMENT, PROLIFERATION, & PERFORMANCE.

PH, OXIDATION-REDUCTION.

COMPOSITION & DISTRIBUTION OF REACTIVE SURFACES.

PRESENCE OF MULTIPLE & MIXED CONTAMINATION

INTERACTION WITH CLIMATE FACTORS

CLIMATE – TEMPERATURECLIMATE – TEMPERATURE

TEMPERATE REGIONS - LIMITED TO WARMER PARTS OF YEAR.

SHORT- TIME AVAILABLE.

OK WHEN NO IMMEDIATE THREAT EXISTS.

WARMING TECHNOLOGIES EXIST/QUESTIONABLE ECONOMIES.

SOIL MATRIX:SOIL MATRIX:

MADE UP OF SOIL PHASES

PHYSIOCHEMICAL PROPERTIES OF pH & REDOX.

CAN INFLUENCE MOBILITY .

CAN REGULATE CONTAMINANT EXPOSURE & SUSCEPTIBILITIES TO BIOLOGICAL TRANSFORMATION /REMOVAL PROCESSES.

CONTROL PROCESSES THAT ELIMINATE/REDUCE EFFECTS OF CONTAMINANTS IN ENVIRONMENT.

IMPACT ORGANICS & METALS DIFFERENTLY.

COLLOIDAL NATURE EFFECTSCOLLOIDAL NATURE EFFECTS REACTIVITY OF SOIL REACTIVITY OF SOIL PHASES PHASES (INORGANIC & ORGANIC)(INORGANIC & ORGANIC)

SOIL COLLOIDS ARE:

– EXTREMELY SMALL SIZE

– LARGE SURFACE AREA

– NEGATIVELY CHARGED SURFACE AREA – INFLUENCE ATTRACTIONOR REPULSION BETWEEN SOIL & CONTAMINANT.

ORGANIC PHASE IN SOIL:ORGANIC PHASE IN SOIL:

HIGH ORGANIC CONTENT IN SOIL

CAN RESULT IN MODERATE TO HIGH LIPOPHILOC ORGANIC TOXICS BEING TRAPPED IN ORGANIC MATTER.

UNAVAILABLE FOR PLANT UPTAKE.

CAN ENHANCE DEGRADATION IN RHIZOPHERES BY STIMULATING MICROBIAL GROWTH & BIOACTIVITY

METALS CAN BOND WITH ORGANICS & REDUCE AVAILABILTY FOR PLANT UPTAKE.

METAL BONDING WITH ORGANICS CAN ASSIST IN SITE STABILIZATION.

ORGANIC PHASE IN SOIL: (cont)ORGANIC PHASE IN SOIL: (cont)

EX. LEAD STABILIZATION

AVAILABILITY OF METALS IN CLAYS WITH HIGH COLLOIDAL SOLIDS WILL BE REDUCED COMPARED WITH SAND SOILS.

BECAUSE: – POSITIVE CHARGED CATIONS OF CONTAMINANTS

ATTRACTED TO NEGATIVE CHARGED MINERAL SURFACES.

– CHELATING AGENTS ARE BEING RESEARCHED TO IMPROVE METAL AVAILABILITY.

MATRIX (SOIL) pH MATRIX (SOIL) pH

EXERTS GREATER IMPACT ON METALS.

PLANTS ABSORB METALS IN IONIC FORM.

METAL CONCENTRATION INCREASES WITH DECREASING pH. (INCREASES HYDROGEN IONS ACTIVITY).

MAY BE TOXIC TO PLANTS.

RESEARCH IS ON ACIDIFIERS.

EX. SULFUR.

OXIDATION-REDUCTION OXIDATION-REDUCTION

MANY ELEMENTS ARE MORE MOBILE DEPENDING ON OXIDATION STATE.

EX. CHROMIUM – Cr6 IS HIGHLY OXIDIZED FORM & IS MORE TOXIC, MORE SOLUBLE & MOBILE THAN Cr3+

(REDUCED FORM).

PHYTOREMEDIATION MAY FAVOR PRESENCE OF Cr6.

OTHER REMOVAL SCHEME MAY BE TO REDUCE Cr6 TO Cr3 AND PRECIPITATE AS INSOLUBLE, IMMOBILE HYDROXIDE, Cr(OH)3.

THE CHOICE IS THE MANAGER’S.

DEEP ROOTED PLANTSDEEP ROOTED PLANTS

EARLY ASSUMPTION THAT PHYTOREMEDIATION DEPTH WAS LIMITED TO 15-30 CM.

RESEARCHERS ARE DEVELOPING DEEP ROOTED PLANT SYSTEMS.

EX. – HYBRID POPLAR TREES.

– GROUNDWATER CONTAINING ATRAZINE AND TNT.

METALS ARE DIFFICULT DUE TO: METALS ARE DIFFICULT DUE TO:

LOW SOLUBILITY

ATTRACTION TO SOIL SURFACES

TEND TO REMAIN IN ROOT ZONES

PRESENCE OF OTHER TOXICSPRESENCE OF OTHER TOXICS

EASILY OVERLOOKED VARIABLE THAT CAN IMPEDE REMEDIATION

MOST CONTAMINATED SITES CONTAIN MIXTURES OF COMPOUNDS (ORGANICS & INORGANICS).

AN EXAUSTIVE CHARCTERIZATION MAY BE REQUIRED FOR DECISION.

MANAGEMENT AIDS MANAGEMENT AIDS

REQUIREMENTS:

– POTENTIAL SUCCESS OF TECHNOLOGY

– STAKEHOLDER CONCERNS

– CAREFUL PLANNING (TEAM OF EXPERT)

– SCHEDULING

– BUDGETING

– IMPLEMENTATION

– MONITORING

– CONTROLLING

MANAGEMENT AIDS (cont) MANAGEMENT AIDS (cont)

PRODUCES EXPECTED RESULTS.

PLANNING:– SITE CONDITIONS– LEGAL REQUIREMENTS– OBJECTIVES & TARGETS

IMPLEMENTATION:– RESPONSIBILITIES/AWARNESS– COMMUNICATION– DOCUMENTATION OF PROCESS

MONITORING: – MEETING OBJECTIVES & TARGETS – ANY CORRECTIVE ACTION

TEAM OF EXPERTS TEAM OF EXPERTS

TECHNICAL EXPERTISE REQUIRED

– MICROBIAL BIOLOGY

– SOIL SCIENCE/GEOLOGY

– HYDROLOGY

– PLANT PHYSIOLOGY

– PROJECT MANAGEMENT

RECOVERY OF CONTAMINANTS RECOVERY OF CONTAMINANTS

HARVEST CONTAMINATED PLANTS

LOW GRADE ORE (PHYTOMINING)

RECYCLED

UNDISTURBED ENVIRONMENT

ESTIMATED FINANCIAL RECOVERIES: ESTIMATED FINANCIAL RECOVERIES:

HYPERACCUMULATOR PRODUCE 10-20 TONS BIOMASS/HECTARE/YR WITH VOLUME 10O KG/HECTER/YR (FOR NICKEL, WOULD RECOVER $550/HECTARE AT MARKET VALUE OF $2.50/LB.)

$960/HECTARE WITH ALFALFA PRODUCTION OF 500 KG OF Zn/HECTARE AT $1.92/KG.

ESTIMATED COMPARISON COSTSESTIMATED COMPARISON COSTS

TECHNOLOGY COST/TON

PHYTOREMEDIATION $25 – 100

ELECTROKINETICS 20 – 200

SOIL FLUSHING 40 – 190

SOIL WASHING 75 - 200

LANDFILLING 100 – 400

VITRIFICATION 400 – 850

CONCLUSIONS CONCLUSIONS

PHYTOREMEDIATION :– PERMANENT IN-SITU OPTION

– PHYTOMINING CAN BE PROFITABLE

– MANY PLANTS HAVE ABILITY TO CONCENTRATE CONTAMINANTS IN SHOOTS & LEAVES

– DEPENDENT ON CLIMATE, MATRIX, pH, REDOX POTENTIAL, KOW, ORGANIC MATTER.

– PLANNING, SCHEDULE, BUDGET, CONTROLS, MONITORING SYSTEM, PROJECT MANAGER, TEAM OF EXPERTS, TOP SUPPORT SUPPORT.

– RECYCLING CAN DEFRAY COSTS.