Correlation between biological and physical availabilities of phenanthrene in soils and soil humin in aging experiments

Journal Article · Sun Aug 01 04:00:00 EDT 1999 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1897/1551-5028(1999)018<1720:CBBAPA>2.3.CO;2· OSTI ID:20012726

White, J C; Hunter, M; Nam, K; Pignatello, J J; Alexander, M

The bioavailability of an organic compound in a soil or sediment commonly declines with the soil-chemical contact time (aging). A series of parallel desorption and bioavailability experiments was carried out on phenanthrene previously aged up to {approximately}100 d in Mount Pleasant silt loam (Mt. Pleasant, NY, USA) or Pahokee peat soil to determine as a function of the aging period the degree of correlation between the reduction in bioavailability and the rate and extent of desorption and the influence of soil organic matter composition on availability. The mineralization of phenanthrene by two bacteria and the uptake of phenanthrene by earthworms showed expected declines with aging. Likewise, the rate of phenanthrene desorption in the absence of organisms decreased with aging. The decline in initial rate of mineralization or desorption was nearly an order of magnitude after 50 to 60 d of aging. Plots of normalized rates of mineralization or desorption practically coincided. Similarly, plots of normalized fraction mineralized or fraction desorbed during an arbitrary period gave comparable slopes. The partial removal of organic matter from the peat by extraction with dilute NaOH to leave the humin fraction reduced the biodegradation of phenanthrene aged for 38 and 63 d as compared to the nonextracted peat, but the effect disappeared at longer incubation times. The rate of desorption from samples of peat previously extracted with NaOH or Na{sub 4}P{sub 2}O{sub 7} declined with aging and, for a given aging period, was significantly slower than from nonextracted peat. This work shows that the reduction in bioavailability of phenanthrene over time in soil is directly correlated with reduction of its physical availability due to desorption limitations. In addition, this study shows that removal of extractable humic substances leads to a decline in the rate of desorption and in the bioavailability of the substrate.

• Research Organization: Connecticut Agricultural Experiment Station, New Haven, CT (US)
• Sponsoring Organization: National Institute of Environmental Health Sciences; US Department of Agriculture; Environmental Protection Agency; National Science Foundation; US Department of Energy
• OSTI ID: 20012726
• Journal Information: Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 8 Vol. 18; ISSN ETOCDK; ISSN 0730-7268
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
BIODEGRADATION
BIOLOGICAL AVAILABILITY
DESORPTION
HUMIC ACIDS
ORGANIC MATTER
PHENANTHRENE
REMEDIAL ACTION
SOILS