PLANTS USED FOR PHYTOREMEDIATION Rashad Reed and Kenong Zhang

BZ 572 Fall 2010November 18, 2010

Plant Classification Ornamental Plants

Pot marigold (Calendula officinalis) Common hollyhock (Althaea rosea) Chinese brake fern (Pteris vittata )

Aquatic Plants Water Hyacinth (Eichhornia crassipes ) Eurasian Watermilfoil (Myriophyllum spicatum) Fool's Watercress (Apium nodiflorum) Duckweed (Lemna trisulca L.)

Pot Marigold and Common Hollyhock

Features of Ornamental Phytoremediation

Employs phytostabilization of pollutants

Found to phytoremediate heavy metals, i.e. Cd, Pb

Organic phyoremediation of petroleum (TPH)

Cultural background and influence (marketing, aesthetics)

Profitability to existing nursery, fertilizer, and gardening industries

Public acceptance

Advantages: Can be used in urban environments without changing existing landscape.

Relatively low costs Non-food chain plants that

can be periodically phytoextracted for pollutants.

Can be genetically modified to not produce pollen or set seed with minimal effect to ecology

Ornamental Phyto Case Study Liu et. Al tested 3 ornamentals, Impatiens Balsamina, Althaea

rosea and Candulata officinalis for ability to tolerate and accumulate Cd and Pb.

Soil and hydro conditions tested Cd levels ranged from 0, 10, 30, 50, 100 mg/Kg-1 Pb was added to Cd in the following concentrations:

0 + 0 (control), 1 + 50, 3 + 50, 5 + 50, 10 + 50, 1 + 100, 3 + 100, 5 + 100 and 10 + 100 mg L-1

Pb(NO3)2 form of bioavailable lead CdCl2·2.5H2O form of bioavailable cadmium

Ornamental Phyto Case StudySoil

Impatiens balsamina had leaves turn brown under >50 mg/Kg C. officinalis height increased as Cd levels increased A. rosea height slightly decreased for levels above 50 mg/Kg

(insignificant) C. officinalis and I. balsamina accumulates more Cd in roots than

the shoot at every Cd level A. rosea accumulates more Cd in shoots for 10, 30, and 50

mg/Kg, but more Cd in the roots under 100 mg/Kg CdCl2·2.5H2O

Ornamental Phyto Case Study

Ornamental Phyto Case Study A. rosea had the highest ability to accumulate Pb, the

maximal Pb concentration in the shoots and roots was 24 and 640 mg kg−1

Phytotoxicity shown (Cd and Pb = 10 + 50 and 10 + 100 mg L−1)

C. officinalis had the highest ability to accumulate Cd, the Cd concentration in the shoots and roots reached 825 and 1585 mg kg−1 in TP4 treatment, 700 and 1492 mg kg−1 in TP8 treatment, respectively

All three plants had a lower general affinity for Pb

Ornamental Phyto Case Study Case study conclusions

C. offinalis is tolerant to Cd levels, but is not a hyperaccumulator since more Cd was found in the roots than in the shoots. Phytostabilization

A. rosea, tolerant to heavy metals and is a hyperaccumulater of Cd when conc. < 100 mg kg-1

Efficacy of ornamentals was examined and has potential for use in urban environments with moderate to high Cd/Pb contamination levels

Fern Phytoremediation Classification: Marattiales, Ophioglossales, and

leptosporangiate ferns Best used in areas of high humidity Ability to uptake high levels of arsenic Industrial applications in phytoremediation Humidity requirements reduces water necessity Fast growing species and varieties available

(increased biomass) Ornamental use: Japanese painted fern

Chinese brake fern and Japanese painted fern

Arsenic accumulation in ferns Ma et al. (2001) reported the first known arsenic

hyperaccumulator Chinese brake fern (Pteris vittata L.). Tu et al. 2002 found that P. vittata grown in an As-

contaminated soil accumulated total dry biomass of 18 g plant-1 after 18 weeks of growth

Chinese brake fern tolerant of high concentrations of arsenic, up to 1,500 mg As kg-1 soil

Ferns operate by phytoextracting Arsenic, As(V) or As(III), storing As in the fronds

Ferns hyperaccumulate As through phosphate transporters and do not have phosphate deficiency symptoms at high levels of As

Fern phytoremediation (mechanism) Contains arsenate reductase (AR) genes to

reduce arsenate to arsenite AR was not detectable in the fronds, suggests

that arsenate reduction, occurs in roots Arsenite is then transported to shoots, where it

may be stored in the vacuoles (Lombi et al., 2002)

75-95% As in the fronds is present in the form of arsenite (Ma et al. 2001, Zhang et al. 2002).

Fern Phytoremediation in Practice 10 μg As/L-1 is the limit set by US EPA Over 29 million people in Bangladesh may be

exposed to over 50 μg/L As. Bangladesh, India, and Pakistan have problems

with ground water contamination from As Up to 7500 mg As/kg on a contaminated site

without showing toxicity symptoms. (Ma et al, 2001)

Contamination comes from industrial and chemical plants, dumping effluent into groundwaters (lack of regulation)

Scope of Arsenic contaminaton

Practical Urban Phytoremediation Hyde Park neighborhood: Augusta, GA

Phyoremediation in practice Low-lying geographic area containing approximately 200

houses and surrounded by industry, abandoned industry, railroad lines and large highways.

Problems of high poverty levels (>70%) Abandoned houses, overgrowth of weeds, snakes, etc. Illegal dumping and drain contamination Lack of community cohesiveness and/or solid leadership Phytoremedation can be used as a part of a larger

objective in urban environmental renewal

Hyde Park Pictures

Bob Safay. ATSDR Regional Representative. U.S. EPA, Region IV released a report in 1994.

The most serious contamination found near the Goldberg site.

From ditch sediments: Highest lead detected was 1800 mg/kg, and the highest level of PCBs was 13.2 mg/kg

From soil samples: lead (1100 mg/kg), arsenic (59 mg/kg), and dioxin/furans (0.0001 mg/kg

Agency for Toxic Substances and Disease Registry report, APPENDIX 3 - MARCH 1994 HEALTH CONSULTATION

Phytoremediation plan Perennials Alpine Pennygrass, Thlaspi caerulescens Hairy Goldenrod, Solidago hispida Yellow Tuft, Alyssum lesbiacum Bladder Campion, Silene vulgaris Horse bean, Vicia faba

Trees and Shrubs Aspen, Populus tremula Shrub violet, Hybanthus floribundus Grasses Indian grass, Sorghastrum nutans Kleingrass, Panicum coloratum Little bluestem, Schizachyrium scoparius Bent grass, Agrostis castellana

Aquatic plants Aquatic plants are those plants living in and adapted

to aquatic environments, which can only grow in water or permanently saturated soil.

Bodies of aquatic plants can be either floating or submerged.

Aquatic plants are often viewed as indicators of aquatic environment pollution.

Living environment of aquatic plants

Rivers Lakes

Constructed Wetlands

Hydroponic systems

Where do they live?

Mechanisms of aquatic plants phytoremediation

Inorganic pollutants Rhizofiltration Phytostabilization Phytoextraction

Organic pollutants Phytodegradation Phytovolatilization Rhizodegradation

Constructed Wetlands High substrate heterogeneity Wide application for pollutants removal

and phytoremediation Act as a cover above contaminated areas Rhizofiltration techniques are the most

commonly used Pollutant removal efficiencies are

significantly related to plant species present

Pollutant Removal Efficiencies of Constructed Wetlands

(Otte and Jacob, 2006)

Benefits and drawback of constructed wetland

Benefits: Aesthetical functions Provide habitat for

wildlife animal species Educational resources Little maintenance

required Increased Cost-

efficiency

Drawbacks: Limited by plant

tolerance and pollutant bioavailability

Limited plant life expectancy

Susceptible to climate change, pollution, and disease

Heavy Metal Heavy metal ions of Cd2+, Hg2+, and Pb2+ are

nonessential and toxic to plants Cu2+, Zn2+, Mn2+, Fe2+, Ni2+, and Co2+ are essential

micronutrients for plants, but toxic when present in high concentration

Hyperaccumulators: plant species tolerate, uptake, and translocate high levels of certain heavy metals that is toxic to other species. Contain >100 mg/kg of Cd, >1000 mg/kg of Cu, or >10,000

mg/kg of Zn and Mn(dry weight in leaves)

Heavy Metal Toxicity Mercury toxicity symptoms

concentration deficits Impaired motor function

Lead toxicity symptoms Learning disability Mental retardation

Chromium toxicity symptoms

Damage DNA Damage kidney

Pb

Hg

Typical Species for Heavy Metal Removal

Eurasian Watermilfoil (Myriophyllum spicatum)

Water Hyacinth (Eichhornia crassipes )

Duckweed (Lemna trisulca L.)

Fool's Watercress (Apium nodiflorum)

Water Hyacinth Floating plant with broad ,thick,

and glossy leaves that the plant body can grow as much as 1m high.

Able to phytoaccumulate metal pollutants contain Ag, Pb, Cd and Zn in municipal and agricultural wastewater.

Known as one of the plants with fastest growth rate that can double population in 2 weeks.

High invasive potential.

Case Study: Removal of Cadmium and Zinc by Water Hyacinth

The stock solution was prepared in distilled water with analytical grade CdCl2. 2½ H2O and ZnSO4.7H2O which was later diluted as required. The plants were maintained in tap water with concentrations of 0.5, 1, 2, 4 mg/L of Cd and 5, 10, 20, 40 mg/L of Zn.

The test durations were 0 (two hours), 4, 8 and 12 days. Relative growth, metal accumulation, and bioconcentration

factor (BCF) are evaluated.

Relative growth (above) and BCF (below)

Relative plant growth Metal Accumulation

Zn

Cd

Cd

Zn

BCF

Cd

Zn

(Lu et al., 2004)

Eurasian watermilfoil Submerged aquatic perennial

plant which grows in still or slow-moving water.

Slender stems up to 3 m long with numerous leaflets thread-like, 4-13 mm long.

Introduced to North America between the 1950s and 1980s where it has become invasive species.

Able to uptake and remove lead, zinc, and copper from wastewater.

Plant tissue was washed with 3% HCl solution previously. Metal source were provided by CuSO4, ZnSO4, and

Pb(NO3)2 to prepare the stock solutions with concentration of 2, 4, 8, 16, 32 and 64 mg/L (doubling). Standard curves were made.

Absorption tests were conducted in 250 ml conical flasks placed on orbital shaker and contact for 2 hours.

Filtrate was analyzed by atomic absorption spectrophotometer (AAS) to determine sample metal concentrations.

Case Study: Removal of Lead, Zinc, and Copper by Eurasian watermilfoil

(Keskinkan et al., 2003)

According to figure 1 (left), equilibrium were reached after about 20 mins after beginning; after that the data was adhered well to the Langmuir equation (see below) which means that absorption was as a monolayer.

The value of metal concentration of solution on time t over the beginning concentration Ct/C0 is shown below:

Compare of the metal uptake capacities (qmax, mg/g) of Myriophyllum spicatum to other plant species:

(Keskinkan et al., 2003)

Fool's Watercress Hollow stems rooting at base and

finely grooved. About 0.3-1m high.

Simply pinnate leaves in shiny bright green in color with 2-4 pairs of  lobes.

Usually find in grown ditches, shallow ponds or very damp places.

Capable to uptake and remove various heavy metals such as Hg, Cr, Pb, Cu, and Zn.

(Vlyssides et al., 2005)

A mathematical model was established to evaluate the inherent capacity of watercress to uptake heavy metals.

Plant uptake rate follows the first order kinetic model depending on the heavy metal concentration in the plant biomass.

This model allowed to evaluate the specific uptake rate and the maximum content within plant biomass.

The relationship between metal concentration in solution Es (mg/L) and plant biomass Ep (mg/g) is:

Case Study: Removal of Copper, Lead etc. by Fool’s Watercress

(Vlyssides et al., 2005)

Change of heavy metal concentrations in solution and

plant biomass(Vlyssides et al., 2005)

The estimated absorption kinetic parameters for various heavy metals, by Apium Nodiflorum using the data acquired

E∞ = the saturation heavy metal concentrations in the plant biomasskm = maximum uptake rate of metal KS = saturation constant(Vlyssides et al.,

2005)

Duckweed Has a very simple structure that

lacks obvious stems or leaves, with small plate-shaped structure floating on water surface.

Reproduction is mainly rely on asexual budding.

High pollutant removal potential due to small size, fast growth, and easy to cluture.

(Kara and Kara, 2004)

The duckweed obtained from natural lake was acclimatized to laboratory conditions for one week before starting research.

Solution of Cadmium was prepared using Cd(NO3)2 and contact with plant sample for different length.

After absorption, water samples were analyzed by AAS at 228.8nm.

Case Study: Removal of Cadmium by Duckweed

Cd removal efficiencies

(Kara and Kara, 2004)

Aquatic Plants VS. Terrestrial Plants in Phytoremediation

Advantages of aquatic plants Faster growth and larger

biomass production rate Relative higher capability of

pollutant uptake Better water purification

effects due to direct contact

GO AQUATIC!

Aquatic Plants VS. Terrestrial Plants in Phytoremediation

Advantages of terrestrial plants More plant-soil microbe

interactions to enhance pollutant uptake

Higher tolerance against severe weather and temperature change

More sophisticated root system

GO TERRESTRIAL!

Conclusions Ornamental phytoremediation is beautiful,

profitable and effective: utilizing phytoextraction and phytostabilization

Ferns hyperaccumulate As which can be useful in contaminated groundwater regions, such as Bangladesh

Hyde Park, Augusta GA has a current and ongoing contamination problem that ornamentals may help to alleviate without affecting food chain or food supply

Conclusions Most of the aquatic plants showed high heavy

metal phytoremediation potential are usually considered as invasive species, which indicates that there are numerous positive aspects of those species that is able to take advantage of

To achieve better remediate effects, more effort is required to accelerate the pace of phytoremediation techniques from laboratory experiment to practical use.

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Design Center for Community Design and Preservation. www.ced.uga.edu/charrettes.html17. Rathinasabapathi, Bali, L.Q. Ma and M Srivastava. (2006) Floriculture, Ornamental and Plant

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the arsenic hyperaccumulator Pteris vittata L. Environmental Pollution. 135, 333-340.19. Internet source, slide 11(b). http://www.shadesofgreenusa.com/Priclist_files/painted_fern1.jpg20. J. Liu, Q. Zhou, T. Sun, L.Q. Ma and S. Wang. (2008) Identification and Chemical Enhancement of Two Ornamental Plants for Phytoremediation. Bull Environ Contam Toxicol 80:260–265.21. J. Liu, Q. Zhou, T. Sun, L.Q. Ma and S. Wang. (2008) Journal of Hazardous Materials 151:261–267.22. Fiegl, J., Bryan P. McDonnell, Jill A. Kostel, Mary E. Finster, and Dr. Kimberly Gray "A Resource Guide:

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Suggested reading material

Checker, Mellissa. (2005) From Friend to Foe and Back Again: Industry and environmental action in the urban south http://www.augustaneeds.com/files/ASU_HydePark_MelissaChecker_2005.pdf

Checker, Mesllisa (2005) Polluted Promises: Environmental Racism and the Search for Justice in a Southern Town. NYU Press, NewYork, NY.