Bioventing remediation and ecotoxicity evaluation of phenanthrene-contaminated soil.
The objectives of soil remediation processes are usually based on threshold levels of soil contaminants. However, during remediation processes, changes in bioavailability and metabolite production can occur, making it necessary to incorporate an ecotoxicity assessment to estimate the risk to ecological receptors. The evolution of contaminants and soil ecotoxicity of artificially phenanthrene-contaminated soil (1000 mg/kg soil) during soil treatment through bioventing was studied in this work. Bioventing was performed in glass columns containing 5.5 kg of phenanthrene-contaminated soil and uncontaminated natural soil over a period of 7 months. Optimum conditions of mineralisation (humidity=60% WHC; C/N/P=100:20:1) were determined in a previous work. The evolution of oxygen consumption, carbon dioxide production, phenanthrene concentration and soil toxicity were studied on sacrificed columns at periods of 0, 3 and 7 months. Toxicity to soil and aquatic organisms was determined using a multispecies system in the soil columns (MS-3). In the optimal bioventing treatability test, we obtained a reduction rate in phenanthrene concentration higher that 93% after 7 months of treatment. The residual toxicity obtained at the end of the treatment was not attributed to the low phenanthrene concentration, but to the ammonia used to restore the optimal C/N ratio.
García Frutos
F Javier
FJ
CIEMAT, Avda. Complutense 22, 28040 Madrid, Spain. garcia.frutos@ciemat.es
Escolano
Olga
O
García
Susana
S
Babín
Mar
M
Fernández
M Dolores
MD
D001673:Biodegradation, Environmental; D002245:Carbon Dioxide; D054750:Ecotoxicology / Q000379:methods; D004787:Environmental Pollution; D010101:Oxygen Consumption; D010616:Phenanthrenes / Q000378:metabolism* / Q000633:toxicity; D012987:Soil; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism* / Q000633:toxicity
D010616:Phenanthrenes; D012987:Soil; D012989:Soil Pollutants; D002245:Carbon Dioxide; C031181:phenanthrene