Phytoremediation in subtropical Hawaii—A review of over 100 plant species

Abstract

Phytoremediation is an emerging remediation technology that utilizes plants and microbes INTRODUCTIONPhytoremediation is an emerging multidisciplinary field of science and technology. It uses plants and associated microbes to cleanse chemically contaminated air, soil, and water. Research activities to advance the science and technology have been carried out in the past decade. Several of its applications are phytoaccumulation, phytovolatilization, phytotransformation, rhizosphere filtration, and phytostabilization.The technology is a permanent treatment option, has low capital and energy costs, and is aesthetically pleasing (U.S. Environmental Protection Agency [USEPA], 2000). It is, however, often incapable of dealing with high chemical concentrations, and is slower than and requires greater land area than alternative treatment methods. A generally accepted hypothesis is that phytoremediation is suitable in warm climates.This encourages research, demonstration, and application of phytoremediation in tropical and subtropical areas.The use of native plants for phytoremediation in Hawaii has a particular appeal, as they are compatible with the island ecosystems.Their use is feasible and alleviates concerns due to a possible introduction of invasive species into fragile ecosystems.In general, advances of phytoremediation were reviewed recently with an emphasis on various aspects. (2003) and Pulford and Watson (2003) reviewed recent progress of heavy metal remediation, the latter specifically addressing the use of trees. Susarla et al. (2002) appraised the treatability of organic contaminants using phytoremediation. Glass (1999) estimated that the U.S. phytoremediation market for 1999 would be between $30-$49 million. Estimated 1999 world phytoremediation markets were $34-$58 million.The focus of this article is recent progresses and advances of phytoremediation in Hawaii, particularly those conducted at the University of Hawaii.The data summarized can serve as a useful database for future investigations on phytoremediation.There are many unseen risks in the Hawaiian Islands. Heavily contaminated areas include several notable Superfund sites such as Pearl Harbor. Further, many thousands of hectares of agricultural land have received large numbers of pesticide applications. A former pesticide mixing and loading site on Oahu contains dioxins (CERCLIS HISFN0905536). A historical military use of the islands has resulted in live-fire areas with explosive residues. Everyday activities also result in pollution, which may be ameliorated through phytoremediation.Wastewaters from various sources often prove to be a challenge to individuals, industries, and municipalities.Trade winds, Hawaii's natural "air conditioner," can scour landscapes, preventing revegetation on previously cleared lands, and the volcanic soils of the islands historically have metal concentrations that often exceed regulated maximum contamination levels.Bench-, pilot-, and field-scale phytoremediation studies have been conducted for several sites and cont...

Mineralization of 2,4,6-Trinitrotoleune (TNT) in Coastal Waters and Sediments

“…The types of whole plants that have been studied include the bush bean (Harvey et al 1990), hybrid poplar (Thompson et al 1998), soybean (Adamia et al 2006), switchgrass (Peterson et al 1998), ryegrass (Sung et al 2004), yellow nutsedge (Palazzo and Leggett 1986) and a variety of wetland species (Best et al 1999a, b, Bhadra et al 1999a, b, Burken et al 2000, Gorge 1994, Paquin et al 2004, Pavlostathis et al 1998. Some investigators have used cell cultures , Vanek et al 2002, Vila et al 2005 or plant extracts (Medina et al 2004) to differentiate between degradation by the plant cells vs the associated microflora.…”

Trinitrotoluene and Its Metabolites in Shoots and Roots of Panicum maximum in Nano-Phytoremediation

“…This procedure followed the method of Wang and Zhang (1997) [6], Choe et al (2001) [7], Sun et al (2007) [8], Jiamjitrpanich et al (2010) [5], and [3], according to equation as below: [9] 2FeCl 3 + 6NaBH 4 + 18H 2 0 → 2Fe 0 (s) + 6B(OH) 3 rhizosphere) and phytoextraction (the contaminants are taken up and stored in the aerial parts of the plant) [1], [2]. The combination of phytoremediation and nanoscale zero valent iron (nZVI) for 2,4,6-trinitrotoluene (TNT) removal in contaminated soil has been recently reported [3]- [5].…”

Molecular tools to understand the bioremediation effect of plants and earthworms on contaminated marine sediments

“…Paspalumvaginatum,a salt-tolerant herbaceous perennial plant,has been successfully used in bioremediation of dredged sediments contaminated by heavy metals and/or polycyclic aromatic hydrocarbons(PAHs).This is because of its high metal and PAHs tolerance [6,7]and its effectiveness intaking up sodium (Na) from the matrix, decreasing 4 salinityand making the medium more amenable to microorganisms and plants [8]. The shrub Tamarixgallicahas also shown great adaptability on salty media and has proven effective at improving contaminated growth media by the adsorption, extraction and/or degradation of conservative and degradable pollutants [9].…”