Influence of surfactants on pyrene desorption and degradation in soils

Abstract

Four surfactants were tested at five concentrations to determine their abilities to solubilize soil-adsorbed pyrene. Inoculation with pyrene degraders in the presence of the surfactant Witconol SN70 was the most effective treatment for pyrene mineralization (46 to 80%) under unsaturated conditions, but the surfactant inhibited the effectiveness of these inoculants in soil slurries.

Microbial surfactants and their use in field studies of soil remediation

“…The role of microorganisms has been shown to be essential in the remediation of, at least, organic pollution, and the activity of microbial types naturally present can be enhanced by bioremediation techniques which include increased aeration of the polluted material and nutrient additions Ivshina et al 1998). Supplementing the source of microorganisms capable of degrading particular pollutants (bioaugmentation) and the enhancement of the desorption of pollutants from particulates using surfactants can increase hydrocarbon degradation (Deschenes et al 1995;Thibault et al 1996;Christofi et al 1998;Ivshina et al 1998). It is only 10-15 years that the use of surfactants in increasing the availability of hydrophobic pollutants in soils and other environments has been considered (Vigon and Rubin 1989).…”

Effects of a Nonionic Surfactant on Biodegradation of Phenanthrene and Hexadecane in Soil

“…Witconol SN70 is a nontoxic [22] linear alcohol ethoxylate (CH 3 (CH 2 ) x (OCH 2 CH 2 ) y OH), where x ϭ 10 to 14 (primarily 10) and y ϭ 5 (average molecular weight ϭ 392 g/mol and specific gravity ϭ 0.98 g/cm 3 ). Published values of the CMC range from 25 to 100 mg/L [15,16]. Our own measurements using a conventional plot of surface tension versus log surfactant concentration suggest a CMC of approx.…”

“…Abdul et al [15] assessed 10 commercial surfactants for their suitability to remove petroleum hydrocarbons from porous media, and Witconol SN70 (nonionic alcohol ethoxylate; Witco, Houston, TX, USA) exhibited the most favorable characteristics for in situ soil and aquifer washing. Furthermore, in biodegradation studies by Thibault et al [16], Witconol SN70 added in combination with a consortium of known pyrene degraders was the most effective treatment for enhancing pyrene mineralization. The positive results reported by Thibault et al [16] and Abdul et al [15] support attempts to use nonionic surfactants such as Witconol SN70 in bioremediation efforts.…”

“…Furthermore, in biodegradation studies by Thibault et al [16], Witconol SN70 added in combination with a consortium of known pyrene degraders was the most effective treatment for enhancing pyrene mineralization. The positive results reported by Thibault et al [16] and Abdul et al [15] support attempts to use nonionic surfactants such as Witconol SN70 in bioremediation efforts. The primary goal of this study was to simultaneously evaluate surfactant sorption, micellization, phenanthrene solubility, and phenanthrene degradation as a function of surfactant dose in both batch and transport environments.…”

Low surfactant concentration increases fungal mineralization of a polychlorinated biphenyl congener but has no effect on overall metabolism

“…Bioavailability is one of the limitations to biodegradation of persistent hydrophobic compounds such as polychlorinated biphenyls (PCBs). There is evidence that surfactants can increase the bioavailability of compounds with low aqueous solubility and thus increase their degradation (Liu 1980;Aronstein et al 1991;Alexander 1992, 1993;Tiehm 1994;Thibault et al 1996); however, in many cases, surfactants can also have a negative influence on biodegradation (Laha and Luthy 1991;Tiehm 1994;Thibault et al 1996). These effects may be due to the surfactant concentration used relative to its critical micellar concentration (CMC).…”