Influence of activated charcoal on desorption kinetics and biodegradation of phenanthrene in soil.

The observed strong sorption of polycyclic aromatic hydrocarbons (PAHs) to black carbon (BC) presents potential implications for PAH bioaccessibility in soils. The effects of BC on the desorption kinetics and mineralization of phenanthrene in four soils was investigated after 1, 25, 50, and 100 d soil-PAH contact time, using sequential hydroxypropyl-β-cyclodextrin (HPCD) extractions in soils amended with 0, 0.1, 1, and 5% (dry wt.

Linking desorption kinetics to phenanthrene biodegradation in soil.

The desorption of polycyclic aromatic hydrocarbons (PAHs) often exhibits a biphasic profile similar to that observed for biodegradation whereby an initial rapid phase of degradation or desorption is followed by a phase of much slower transformation or release. Most investigations to-date have utilised a polymeric sorbent, such as Tenax, to characterise desorption, which is methodologically unsuitable for the analysis of soil. In this study, desorption kinetics of (14)C-phenanthrene were measured by consecutive extraction using aqueous solutions of hydroxypropyl-beta-cyclodextrin (HPCD).

Biogenic volatile organic compounds as a potential stimulator for organic contaminant degradation by soil microorganisms.

The effects of monoterpenes on the degradation of (14)C-2,4-dichlorophenol (DCP) were investigated in soils collected from areas surrounding monoterpene and non-monoterpene-emitting vegetation. Indigenous microorganisms degraded (14)C-2,4-DCP to (14)CO(2), after 1d contact time. Degradation was enhanced by prior exposure of the soils to 2,4-DCP for 32 d, increasing extents of mineralisation up to 60%.

Assessing biodegradation potential of PAHs in complex multi-contaminant matrices.

This study sought to extend validation of a cyclodextrin based extraction method for the assessment of PAH-biodegradation potential to complex multi-contaminant matrices. To this end, four reference materials (RMs) were produced by blending, in different proportions, soils impacted with diesel, lubricating oil and spent oxide. These reference materials had modest summation operatorPAH (16 US EPA) concentrations that ranged from 5.

Impact of black carbon in the extraction and mineralization of phenanthrene in soil.

During the past century, increased biomass burning and fossil fuel consumption have drastically increased the input of black carbon (BC) into the environment, and that has been shown to influence the behavior of organic contaminants in soil. A study was conducted to investigate the effects of BC on the relationship between aqueous hydroxypropyl-beta-cyclodextrin (HPCD) extraction and microbial mineralization (bioaccessibility) of 14C-phenanthrene (10 mg kg(-1)) in four soils amended with 0, 0.1, 0.

Relationship between cyclodextrin extraction and biodegradation of phenanthrene in soil.

A number of soil extraction techniques have been proposed to determine the microbial degradability of organic contaminants in soil. Exhaustive methods using organic solvents have little relevance to the concentration of contaminants actually available to microorganisms. The present study investigated the relationship between sequential hydroxypropyl-beta-cyclodextrin (HPCD) extractions and microbial mineralization of [14C]phenanthrene in four soils over time.

Development of phenanthrene catabolism in natural and artificial soils.

The characteristics of natural soils often vary from those of artificial soil (e.g. OECD), which may lead to substantial differences in the bioavailability of test substances.

Biodegradation of 2,4-dichlorophenol in the presence of volatile organic compounds in soils under different vegetation types.

It has been suggested that monoterpenes emitted within the soil profile, either by roots or by decaying biomass, may enhance the biodegradation of organic pollutants. The aim of this study was to evaluate the effect of biogenic volatile organic compounds (VOCs) on the catabolism of 2,4-dichlorophenol in soils. Soils were collected from areas surrounding monoterpene (woodland) and nonmonoterpene (grassland)-emitting vegetation types.

Can microbial mineralization be used to estimate microbial availability of organic contaminants in soil?

The aim of this study was to characterize the behaviour of a PAH-degrading bacterium to determine whether mineralization plateaus as a result of substrate removal, a decrease in microbial activity or nutrient availability in sterile soils over time. To investigate this, the mineralization of 14C-phenanthrene was measured until it plateaued; subsequently, additional 14C-phenanthrene, catabolic inocula or nutrients were introduced and mineralization was measured for a further 10 d. Cell numbers were also measured together with 14C-uptake into microbial biomass.