Surfactant-facilitated remediation of metal-contaminated soils: efficacy and toxicological consequences to earthworms.
The effectiveness of surfactant formulations to remove aged metals from a field soil and their influence on soil toxicity was investigated. Batch studies were conducted to evaluate the efficacy of cationic (1-dodecylpyridinium chloride; DPC), nonionic (oleyl dimethyl benzyl ammonium chloride; trade name Ammonyx KP), and anionic (rhamnolipid biosurfactant blend; trade name JBR-425) surfactants for extracting Zn, Cu, Pb, and Cd from a soil subjected to more than 80 years of metal deposition. All three surfactants enhanced removal of the target metals. The anionic biosurfactant JBR-425 was most effective, reducing Zn, Cu, Pb, and Cd in the soil by 39, 56, 68, and 43%, respectively, compared with less than 6% removal by water alone. Progressive acidification of the surfactants with citric acid buffer or addition of ethylenediaminetetra-acetic acid (EDTA) further improved extraction efficiency, with more than 95% extraction of all four metals by surfactants acidified to pH 3.6 and generally greater than 90% removal of all metals with addition of 0.1 M EDTA. In two species of earthworm, Eisenia fetida and Lumbricus terrestris, metal bioaccumulation was reduced by approximately 30 to 80%, total biomass was enhanced by approximately threefold to sixfold, and survival was increased to greater than 75% in surfactant-remediated soil compared with untreated soil. The data indicate that surfactant washing may be a feasible approach to treat surface soils contaminated with a variety of metals, even if those metals have been present for nearly a century, and that the toxicity and potential for metal accumulation in biota from the treated soils may be significantly reduced.
Slizovskiy
Ilya B
IB
Muhlenberg College, Department of Chemistry, Allentown, Pennsylvania, USA.
Kelsey
Jason W
JW
Hatzinger
Paul B
PB
D000818:Animals; D002104:Cadmium / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D003300:Copper / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D004492:Edetic Acid / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007854:Lead / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D008670:Metals / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity; D009835:Oligochaeta / Q000187:drug effects*; D011726:Pyridinium Compounds / Q000737:chemistry / Q000633:toxicity; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity; D013501:Surface-Active Agents / Q000737:chemistry* / Q000633:toxicity; D015032:Zinc / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity
D008670:Metals; D011726:Pyridinium Compounds; D012987:Soil; D012989:Soil Pollutants; D013501:Surface-Active Agents; D002104:Cadmium; C001524:Laurosept; D007854:Lead; D003300:Copper; D004492:Edetic Acid; D015032:Zinc