The effect of soil: water ratios on the mineralisation of phenanthrene: LNAPL mixtures in soil.
Contamination of soil by polycyclic aromatic hydrocarbons is frequently associated with non-aqueous-phase liquids. Measurement of the catabolic potential of a soil or determination of the biodegradable fraction of a contaminant can be done using a slurried soil respirometric system. This work assessed the impact of increasing the concentration of transformer oil and soil:water ratio on the microbial catabolism of [(14)C]phenanthrene to (14)CO(2) by a phenanthrene-degrading inoculum. Slurrying (1:1, 1:2, 1:3 and 1:5 soil:water ratios) consistently resulted in statistically higher rates and extents of mineralisation than the non-slurried system (2:1 soil:water ratio; P<0.01). The maximum extents of mineralisation observed occurred in the 1:2-1:5 soil:water ratio microcosms irrespective of transformer oil concentration. Transformer oil concentrations investigated displayed no statistically significant effect on total mineralisation (P>0.05). Soil slurries 1:2 or greater, but less than 1:5 (soil:water), are recommended for bioassay determinations of total contaminant bioavailability due to greater overall mineralisation and improved reproducibility.
Doick
Kieron J
KJ
Department of Environmental Science, Institute of Environmental and Natural Science, Lancaster University, Lancaster LA1 4YQ, UK.
Semple
Kirk T
KT
D001673:Biodegradation, Environmental; D002245:Carbon Dioxide / Q000032:analysis; D007219:Industrial Oils / Q000032:analysis; D008899:Mineral Oil / Q000032:analysis; D008903:Minerals / Q000737:chemistry; D010616:Phenanthrenes / Q000737:chemistry*; D011549:Pseudomonas / Q000378:metabolism*; D015203:Reproducibility of Results; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis*; D014867:Water
D008903:Minerals; D010616:Phenanthrenes; D012987:Soil; D012989:Soil Pollutants; D014867:Water; D002245:Carbon Dioxide; C031181:phenanthrene; D008899:Mineral Oil