Green Chemistry for Green Treatment Technologies Ceyda Senem Uyguner-Demirel and Miray Bekbolet Abstract The implementation of clean, eco-friendly, less energy and waste producing processes and technologies is realized today with an increasing interest. In order to provide a sustainable development, environmentally friendly sub- stances, novel technologies and new green chemistry options should be exploited. In that respect, in this chapter green chemistry and its principles are reviewed in relation to green technologies for the removal of emerging compounds from water and wastewater. //// Emerging compounds Removal from Wastewater- Natural and solar based treatments ///
4.5 Perspectives Phytoremediation has received considerable attention from researchers and is widely viewed as a green technology for the remediation of polluted environments, but it is not yet exploited as a commercial platform technology. However, the increasing pace of genome sequencing will lead to the discovery of further metal- related genes that can be tested in transgenic plants for phytoremediation applications. Gene transfer techniques already allow plastid targeting and the simultaneous transfer and expression of several genes. Therefore, novel infor- mation about plant metabolism and plant–microbe interactions will facilitate the development of novel phytoremediation strategies to clean up soils polluted with heavy metals. If the phytoremediation of polluted soils is possible using transgenic plants that can accumulate metals without negative effects, then it should also be possible to enhance crops with micronutrients such as Fe and Zn, particularly in areas where soils are depleted or where bioavailability is limited. A better understanding of the genetic factors that control the accumulation, metabolism, and tolerance of metals in plants will allow plants to be utilized efficiently for both phytoremediation and biofortification.
Glick BR (2003) Phytoremediation: synergistic use of plants and bacteria to clean up the environment. Biotechnol Adv 21:383–393
Dushenkov S, Kapulnik Y (2000) Phytofiltration of metals. In: Raskin I, Ensley BD (eds) Phytoremediation of toxic metals. Using plants to clean up the environment. Wiley, New York, pp 89–106
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Sampling of Plant Species Studied for Phytoremediation The following is a sampling of plant species that have been studied for phytoremediation. Some plants on this list may not be well suited for growing conditions in Puget Sound. A number of plants with identifi ed phytoremediative abilities have not been included on this list because they are an invasive or potentially invasive weed in Washington state. These plants include such species as: Amorpha fruticosa (Indigo bush) Accumulates lead Azolla pinnata (Water velvet) Biosorbs metals Bacopa monnieri (Water hyssop) Accumulates metals Hydrilla verticillata (Hydrilla) Hyperaccumulates metals Myriophyllum aquaticum (Parrot feather) Transforms and degrades a variety of contaminants Phragmites australis (Common reed) Used in reed bed treatment systems (native genotypes do exist that are not considered invasive) Related native species may not react to contaminants in the same manner as those specifi ed. Different cultivars of the same species and various species of the same genus may differ in reactions and responses to climatic factors (McCutcheon, 2003). GRASSES/LEGUMES C ONTAMINANT P ROCESS C OMMENTS Hydrocarbons Rhizodegradation Metals Hyperaccumulation Hydrocarbons Rhizodegradation Buchloe dactyloides Buffalo grass Hydrocarbons Rhizodegradation/ Accumulation Cerastium arvense Field chickweed Cadmium Uptake/ Accumulation Claytonia perfoliata Miner’s lettuce Cadmium Uptake/ Accumulation Cynodon dactylon Bermuda grass Hydrocarbons Rhizodegradation/ Accumulation Perennial grass used in pastures/lawns; shown in studies to enhance degradation of TPH and PAHs in soils (McCutcheon & Schnoor, 2003). Perennial A. castellana has been shown to accumulate As, Pb, Zn, Mn and Al. Used for low-water use lawn and pasture grass. Has shown promise in grass mixes to enhance degradation of PAHs in soils (McCutcheon & Schnoor, 2003). Perennial grass; low maintenance, drought tolerant lawn requiring little/no mowing. In studies has been shown to reduce TPH and PAHs in soil (McCutcheon & Schnoor, 2003). Tufted perennial, white fl owers. A Northwest (NW) native, a recent study on Vashon Island indicated uptake of cadmium (Institute for Environmental Research and Education, 2003). Additional chickweed varieties found in the NW include C. beringianum (Bering chickweed) and C. fi scherianum (Fisher’s chickweed). A somewhat succulent annual with white or pink fl owers. Also known as Montia perfoliata. A smaller attractive variety is Montia spathulata. A recent study on Vashon Island indicated uptake and accumulation of cadmium (Institute for Environmental Research and Education, 2003). Lawn grass; minimum maintenance but needs mowing and can be invasive. In studies where mixed with other grasses, it has reduced TPH and PAHs in soils (McCutcheon & Schnoor, 2003). S PECIES /C OMMON N AME Agropyron smithii Western wheat grass Agrostis castellana Colonial bentgrass Bouteloua gracilis Blue gamma grass 209GRASSES/LEGUMES S PECIES /C OMMON N AME Elymus Canadensis Canadian wild rye C ONTAMINANT P ROCESS C OMMENTS Hydrocarbons Rhizodegradation/ Accumulation Festuca arundinacea Tall fescue Pyrene, PAHs Rhizodegradation/ Phytoextraction Festuca rubra Red fescue Hydrocarbons Rhizodegradation Lolium perenne English ryegrass Hydrocarbons/ Nutrients Rhizodegradation/ Uptake Lupinus albus White lupin Arsenic Rhizoaccumulation Lotus corniculatus Birds-foot trefoil Hydrocarbons Rhizodegradation/ Accumulation Melilotus offi cinalis Yellow sweet clover Hyrdocarbons Rhizodegradation Panicum virgatum Switch grass Hydrocarbons Rhizodegradation Stellaria calycantha Northern starwort Cadmium Uptake/ Accumulation Stenotaphrum secundatum St. Augustine grass Hydrocarbons Rhizodegradation Trifolium pratense Red clover Hydrocarbons Rhizodegradation Trifolium repens White clover Hydrocarbons PCBs Rhizodegradation/ Metablolization Vicia spp. Vetch Nutrients/ Metals Uptake In combination with other grasses, was shown to reduce PAHs in soils (McCutcheon & Schnoor, 2003). E. mollis is a NW native wild rye. Introduced perennial grass common in the NW; studies have shown enhanced degradation of recalcitrant PAHs (McCutcheon, 2003). Also helpful in uptake of nutrients: nitrogen, phosphorus and potassium (Christensen-Kirsh, 1996). Perennial grass often used in lawn mixes; Studies have shown enhanced degradation of TPH and PAHs (McCutcheon & Schnoor, 2003). Perennial grass shown to uptake nutrients and to signifi cantly enhance degradation of TPH and PAHs in soils (McCutcheon & Schnoor, 2003). A nitrogen fi xing legume capable of growth in acidic soils with low nutrient availability. A recent study indicated an ability to take up arsenic, primarily stored in the root structure (Esteban, Vazquez & Carpena, 2003). A number of lupine varieties are native to the NW, including: Lupinus arcticus (Artic lupine), L. littoralis (Seashore lupin), L. nootkatensis (Nootka lupine), and L. polyphyllus (Large- leaved lupine). An introduced European annual herb; when mixed with grasses was shown to reduce TPH and PAHs in soils (McCutcheon & Schnoor, 2003). This plant is generally not recommended for introduction into constructed wetlands of the Puget Sound region (Azous & Horner, 2001). Tall, sweet smelling annual; M. alba is more common in NW region. When mixed with other grasses was shown to degrade TPH in soils (McCutcheon & Schnoor, 2003). Also helpful in uptake of nutrients: nitrogen, phosphorus and potassium (Christensen-Kirsh, 1996). Enhances degradation of PAHs in soils (McCutcheon & Schnoor, 2003). P. occidentale is a species found in the NW. Low sprawling perennial. A number of varieties are common in the NW, including, S. longifolia (Long-leaved starwort) and S. longipes (Long-stalked starwort). A recent study on Vashon Island indicated uptake and accumulation of cadmium (Institute for Environmental Research and Education, 2003). Perennial grass often used in lawns; coarse-textured. Decreases TPH and PAHs in soils (McCutcheon & Schnoor, 2003). Introduced perennial herb common in the NW. When mixed with other grasses was shown to degrade TPH in soils (McCutcheon & Schnoor, 2003). Introduced perennial herb, deep rooting; enhances microbial activity and degradation of PAHs. Nitrogen fi xer, and PCB metabolizer. Perennial herb, takes up nutrients (nitrogen, phosphorus and potassium); V. faba has been shown to accumulate Al (McCutcheon & Schnoor, 2003). 210 • LID Technical Guidance Manual for Puget SoundOTHER FORBES C ONTAMINANT P ROCESS C OMMENTS Cadmium Uptake/ Accumulation Allium schoenoprasum Chives Cadmium Hyperaccumulation Atriplex hortensis Garden Orach PCBs Metabolism Brassica juncea Indian mustard metals Rhizofi ltration/ Hyperaccumulation Brassica rapa Field mustard Digitalis purpurea Common Foxglove Cadmium, Zinc Hyperaccumulation Perennial aromatic herb native to the NW. Also known as A. borealis. A recent study on Vashon Island indicated uptake and accumulation of cadmium (Institute for Environmental Research and Education, 2003). Perennial onion relative. A recent agricultural study in Israel indicated Cd was accumulated in roots and leaves (Khadka, Vonshak, Dudai & Golan-Goldhirsh, 2003). Of the spinach family, Orache is an extremely variable species; A. patula (Spearscale), A. subspicata and A. patula common in the NW. Shows promise transforming PAH and Graden Orach metabolizes PCBs (McCutcheon & Schnoor). Various species applicable for removing heavy metals (Pb, Zn, Ni, Cu, Cr, Cd and Ur) from soil or water (McCutcheon & Schnoor, 2003); B. campestris (also known as B. rapa) and B. camestris are common annual herb species in the NW. Known to accumulate metals. Cadmium Phytoextraction Helianthus annuus Sunfl ower Metals PAHs Extraction/ Metabolism Rhizodegradation Pteris vittata Brake fern Senecia glaucus Arsenic Hyperaccumulation Crude Oil Rhizodegradation Solidago hispida Hairy golden rod Metals Hyperaccumulation Thlaspi caerulescens Alpine pennycress Cadmium, Zinc, Nickel Hyperaccumulation S PECIES /C OMMON N AME Achillea millefolium Yarrow A recent study on Vashon Island indicated uptake of cadmium; D. lanata (Grecian foxglove) shown to transform digitoxigenin (McCutcheon & Schnoor, 2003). The common sunfl ower has been the subject of numerous studies and is used to extract heavy metals (Pb, Ur, Sr, Cs, Cr, Cd, Cu, Mn, Ni and Zn). Has shown promise in degrading PAHs in soil (McCutcheon & Schnoor, 2003). P. vittata accumulates arsenic in its above ground shoots (Caille et al., 2003). Observed to rhizodegrade crude oil in Kuwait; Senecio triangularis (Arrow-leaved groundsel), S. pseudoarnica (Beach groundsel), and S. intergerrimus (Western groundsel) are among the related perennial herbs in the NW. Shown to accumulate Al. Solidago species shows promise for metabolizing TCE (McCutcheon & Schnoor, 2003). Related NW species include S. Canadensis(Canada goldenrod) and S. multiradiata (Northern goldenrod). This plant is well recognized for its ability to hyperaccumulate metals. T. arvense (Field pennycress) is a common NW annual weed. Appendix 6: Phytoremediation Plant List • 211TREES, SHRUBS and VINES S PECIES /C OMMON N AME Acer rubrum Red maple C ONTAMINANT Leachate P ROCESS Uptake Betula pendula European white birch PAHs PCBs Phytodegradation Gleditsia triacanthos Honey locust Lead Phytoextraction Ilex spp. Holly Cadmium Accumulation Liquidambar styracifl ua American sweet gum Perchlorate Phytodegradation/ Rhizodegradation Maclura pomifera Osage orange PCBs Rhizodegradation Morus rubra Mulberry PAHs PCBs Rhizodegradation Populus spp. Poplars Chlorinated solvents, PAHs, atrazine, DDT, carbon tetrachloride Phytodegradation/ Phytovolatilization Phytoextraction Populus tremula Aspen Pb Extraction Rosa spp. Paul’s scarlet rose Organic contaminants Phytodegradation 212 • LID Technical Guidance Manual for Puget Sound C OMMENTS Fairly fast growing deciduous trees that have been utilized to uptake landfi ll leachate along with hybrid poplars (McCutcheon & Schnoor, 2003). NW species include A. macrophyllum (Oregon maple), A. circinatum (Vine maple), and A. glabrum (Rocky mountain maple). Attractive European native, has been shown in laboratory tests to degrade PAHs and PCBs in solution (McCutcheon & Schnoor, 2003). Common honey locust (many cultivars available) has shown promise in the extraction and accumulation of lead (Gawronski, 2003). Evergreen shrub or tree. Recently shown to take up and accumulate cadmium (Institute for Environmental Research and Education, 2003). A native of the eastern U.S., grows to 60 ft., and is tolerant of damp soils. Has shown promise for phytoremediation of perchlorate (McCutcheon & Schnoor, 2003). A deciduous tree that can withstand heat, cold, wind, drought, and poor soil. Roots have been shown to stimulate PCB-degrading bacteria in the soil (McCutcheon & Schnoor, 2003). The mulberry is one of a few trees producing phenolic compounds stimulating PCB-degrading bacteria, and thus enhance the degradation of this pollutant. Mulberry has also been shown in the lab to degrade PAHs (McCutcheon & Schnoor, 2003). Deciduous trees known for deep rooting and rapid growth. The focus of major attention in the fi eld of phytoremediation, hybrids and clones have been developed for very fast growth and colonization. Poplars can absorb nutrients, such as nitrogen, at a high rate and are used in treatment of land applications of wastewater (McCutcheon & Schnoor, 2003). Known to take up and transform TCE from groundwater (McCutcheon & Schnoor, 2003). Varieties tested include P. deltoids (Eastern cottonwood), P. trichocarpa (Black cottonwood), P. simonii (Chinese poplar) and P. nigra (Lombardy poplar). P. trichocarpa is a NW native. P. tremula, P. treumloides (Trembling aspen), and hybrids have shown potential to remediate contaminated water, either from the soil or water table, esp. the extraction of lead (McCutcheon & Schnoor, 2003). Paul’s scarlet rose is a red, natural climbing rose that can metabolize tetrachlorinated PCB 77. There are, of course many varieties. R. gymnocarpa (Dwarf rose) and R. nutkana (Nootka rose) are two Washington natives.
TREES, SHRUBS and VINESS PECIES /C OMMON N AME
Salix spp. Willow C ONTAMINANT Perchlorate Viola spp. Violets Metals P ROCESS Phytodegradation/ Rhizodegradation Phytoextraction Phytoextraction/ Hyperaccumulation
C OMMENTS Deciduous trees or shrubs needing plenty of water. S. caroliniana (Coastal plain willow) and S. nigra (Black willow) shown to uptake and degrade percholate in soils as well as phytoextract metals (Cd, Zn and Cu). Additional Salix ssp. and hybrids have extracted metals (Cr, Hg, Se and Zn) (McCutcheon & Schnoor, 2003). Species in the NW include, S. commutata (Undergreen willow), S. lucida (Pacifi c willow), and S. sitchensis (Sitka willow). A study on Vashon Island indicated uptake/accumulation of cadmium by S. scouleriana (Scouler’s willow) (Institute of Env. Research & Ed., 2003).
Perennial fl owering plants with many varieties. Hybanthus fl oribundus (Shrub violet) from Australia, has been found to accumulate high concentrations of metals. A study on Vashon Island, WA found violets growing naturally to have accumulated cadmium (Institute for Environmental Research and Education, 2003). The many varieties in the NW include: V. adunca (Early blue violet), V. langsdorfi i (Alaskan violet), V. palustris (Marsh violet), and V. glabella (Yellow wood violet). Sources: Phytoremediation Adams, E.B. (1992 December). Wetlands: Nature’s Water Purifi ers. Clean Water for Washington. Washington State University Cooperative Extension and Washington Department of Ecology. EB1723. Azous, A.L., and Horner, R.R. (Eds.). (2001). Wetlands and Urbanization: Implications for the Future. Boca Raton, FL : Lewis Publishers. Bretsch, K. (2003). Remediation of stormwater residuals decant with hydrocotyle ranunculoides. In U.S. EPA National Conference on Urban Storm Water: Enhancing Programs at the Local Level. Chicago, IL, February 17-20, 2003. Christensen-Kirsh, K.M. (1996). Phytoremediation and wastewater effl uent disposal: Guidelines for landscape planners and designers. Master’s Project, Department of Landscape Architecture. University of Oregon. Crawford, C. (1982). Wetland Plants of King County and Puget Sound Lowlands. King County, WA: King County Resource Planning Section. Esteban, E, Vazquez, S and Carpena, R. (2003) White Lupin Response to Arsenate. University of Madrid, Spain. In COST Action 837 “Workshop on Phytoremediation of toxic metals.” Stockholm, Sweden, June 12-15, 2003. Retrieved March 10, 2004 from http://lbewww.epfl .ch/COST837/abstracts_stockholm/posters.pdf Gawronski, S.W., Raczka, M., & Trampczynska, A. (2003). Ornamental tress and shrubs as phytoremediants. In COST Action 837 “Workshop on Phytoremediation of toxic metals.” Stockholm, Sweden, June 12-15, 2003. Retrieved March 10, 2004 from http://lbewww.epfl .ch/COST837/abstracts_stockholm/posters.pdf Hogan, E.L. (ed.). (1990). Sunset Western Garden Book. Menlo Park, CA: Lane Publishing Co. Institute for Environmental Research and Education (IERE). (2003 January). Vashon Heavy Metal Phytoremediation Study Sampling and Analysis Strategy (DRAFT). (Available from the IERE, P.O. Box 2449, Vashon, WA 98070-2449.)
Appendix 6: Phytoremediation Plant List • 213Khadka, U., Vonshak, A., Dudai, N., Golan-Goldhirsh, A. (2003). Response of Allium schoenoprasum to Cadmium in hydroponic growth medium. In COST Action 837 “Workshop on Phytoremediation of toxic metals.” Stockholm, Sweden, June 12-15, 2003. Retrieved March 10, 2004 from http://lbewww.epfl .ch/COST837/abstracts_stockholm/posters.pdf McCutcheon, S.C., & Schnoor, J.L. (Eds.). (2003). Phytoremediation: Transformation and Control of Contaminants. Hoboken, New Jersey: Wiley-Interscience, Inc. Pojar, J., & MacKinnon, A. (1994). Plants of the Pacifi c Northwest Coast: Washington, Oregon, British Columbia & Alaska. Vancouver, B.C.: Lone Pine Publishing. Washington Department of Ecology. (2001 June). An Aquatic Plant Identifi cation Manual For Washington’s Freshwater Plants. Olympia, WA, Author. Washington State Weed Control Board, Washington State Noxious Weed List, Retrieved June, 2004 from http://www.nwcb.wa.gov/weed_info/contents_common.html Weinmann, F., Boule, M., Brunner, K., Malek, J., & Yoshino, V. (1984). Wetland Plants of the Pacifi c Northwest. Seattle, WA: U.S. Army Corps of Engineers, Seattle District. 214 • LID Technical Guidance Manual for Puget Sound