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Degradation kinetics of aromatic organic solutes introduced into a heterogeneous aquifer
Author(s) -
MacIntyre William G.,
Boggs Mark,
Antworth Christopher P.,
Stauffer Thomas B.
Publication year - 1993
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/93wr02276
Subject(s) - degradation (telecommunications) , naphthalene , aquifer , plume , benzene , reaction rate constant , sorption , chemistry , environmental chemistry , population , kinetics , environmental science , thermodynamics , groundwater , geology , organic chemistry , geotechnical engineering , telecommunications , physics , demography , adsorption , quantum mechanics , sociology , computer science
Degradation rates of benzene, p‐xylene, naphthalene, and o‐dichlorobenzene have been measured in a heterogeneous, unconfined aquifer during a pulse injection experiment at Columbus Air Force Base, Columbus, Mississippi. Dissolved oxygen in the pulse plume maintained aerobic conditions. Degradation kinetics calculated from the complete field data set were approximately first order with the following rate constants: benzene, 0.0070 d −1 ; p‐xylene, 0.0107 d −1 ; naphthalene, 0.0064 d −1 ; and o‐dichlorobenzene, 0.0046 d −1 . Reaction rates were also calculated from a near‐field subset of the data using a model based on the hydrologic characteristics of the aquifer. Shapes of the degradation rate curves were consistent with microbial degradation processes. Maximum degradation rates obtained are presumed to be characteristic of the microbial population metabolism. Carbon 14‐labeled p‐xylene was included in the injection solution to permit detection of degradation products. This technique is suggested for future field experiments, because it distinguishes solute degradation from solute losses by sorption and evaporation and allows mass balance to be demonstrated throughout the course of the reaction in the aquifer.