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Reducing salinity and organic contaminants in the Pearl Harbor dredged material using soil amendments and plants
Author(s) -
Hue N. V.,
Campbell S.,
Li Q. X.,
Lee C. R.,
Fong J.
Publication year - 2002
Publication title -
remediation journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.762
H-Index - 27
eISSN - 1520-6831
pISSN - 1051-5658
DOI - 10.1002/rem.10045
Subject(s) - agronomy , salinity , compost , biosolids , cynodon dactylon , dry weight , environmental science , germination , festuca arundinacea , biology , poaceae , environmental engineering , ecology
Phytoremediation is an emerging technique that can be used to economically remediate sites contaminated withtrace elements and/or man‐made organic contaminants. This technique was used on Pearl Harbor (Oahu,Hawaii) dredged material (PHDM) containing polycyclic aromatic hydrocarbons (PAHs) andsome heavy metals. The dredged material was first amended with a high‐calcium soil (WaialuaMollisol) and a biosolids‐based compost at different proportions to yield varying salinity levels. Amixture that yielded an electrical conductivity (EC, a measure of salinity) of the saturated pasteextract of 15 to 20 dS/m was identified and used to evaluate the salt tolerance of five plant species. Relativegermination and one‐month‐old biomass indicated that common bermuda grass ( Cynodondactylon ), seashore paspalum ( Paspalum vaginatum ), beach pea( Vigna marina ), and cow pea ( Vigna unguiculata ) can produceat least 40 percent of biomass of the control at an EC of approximately 18 dS/m, suggesting the four plants arerelatively salt tolerant. In contrast, Desmodium intortum either did not germinate or died withintwo weeks after germination at the same salinity level. A subsequent greenhouse experiment, using mixtures of thePHDM (0 or 25 percent dry weight), organic amendments (10 percent leucaena green manure orbiosolids‐based compost), and a Mollisol (65 or 90 percent dry weight) in 6‐liter potscontaining 4 kilograms of material yielded the following results: (1) A combination of transplantedseashore paspalum, seeded bermuda grass, and seeded beach pea was effective in taking up sodium (Na),thereby reducing salinity and making the medium more amenable to diversified microbes and plants, which may beeffective PAH degraders; (2) total PAH concentration was reduced by about 30 percent after threemonths of active plant growth, but degradation of individual PAH members varied significantly, however;(3) leguminous green manure, as a soil amendment, was more effective than compost for use in bio‐and/or phytoremediations; and (4) soil amendments, when applicable, could supplement livingplants in reducing organic contaminants, such as PAHs. © 2002 Wiley Periodicals, Inc.