Record Display for the EPA National Library Catalog


Main Title Optimizing BTEX Biodegradation under Denitrifying Conditions.
Author Hutchins, S. R. ;
CORP Author Robert S. Kerr Environmental Research Lab., Ada, OK.
Publisher c1991
Year Published 1991
Report Number EPA/600/J-91/288;
Stock Number PB92-124262
Additional Subjects Water pollution control ; Biodegradation ; Petroleum products ; Ground water ; Denitrification ; Aquifers ; Underground storage ; Storage tanks ; Leakage ; Environmental transport ; Experimental design ; Benzene ; Toluene ; Xylenes ; Microorganisms ; Nutrients ; Reprints ; Benzene/ethyl ; Traverse City(Michigan)
Library Call Number Additional Info Location Last
NTIS  PB92-124262 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 14p
Leaking underground storage tanks are a major source of ground water contamination by petroleum hydrocarbons. Gasoline and other fuels contain benzene, toluene, ethylbenzene, and xylenes (collectively known as BTEX), which are hazardous compounds, regulated by the U.S. Environmental Protection Agency (EPA). Laboratory tests were conducted to determine optimum conditions for benzene, toluene, ethylbenzene, and xylene (collectively known as BTEX) biodegradation by aquifer microorganisms under denitrifying conditions. Microcosms, constructed with aquifer samples from Traverse City, Michigan, were amended with selected concentrations of nutrients and one or more hydrocarbons. Toluene, ethylbenzene, m-xylene, and p-xylene, were degraded to below 5 micrograms/L when present as sole source substrates; stoichiometric calculations indicated that nitrate removal was sufficient to account for 70 to 80% of the compounds being mineralized. o-Xylene was recalcitrant when present as a sole source substrate, but was slowly degraded in the presence of the other hydrocarbons. Benzene was not degraded within one year, regardless of whether it was available as a sole source substrate or in combination with toluene, phenol, or catechol. Pre-exposure to low levels of BTEX and nutrients had variable effects, as did the addition of different concentrations of ammonia and phosphate. Nitrate concentrations as high as 500 mg/L NO3-N were slightly inhibitory. These data indicate that nitrate-mediated biodegradation of BTEX at Traverse City can occur under a variety of environmental conditions with rates relatively independent of nutrient concentrations. However, the data reaffirm that benzene is recalcitrant under strictly anaerobic conditions in these samples.