ARS | Publication request: FACTORS AFFECTING MICROBIAL DEGRADATION OF POLYCYCLIC AROMATIC HYDROCARBON PHENANTHRENE IN THE CARIBBEAN COASTAL WATER

Submitted to: Marine Pollution Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 24, 1999
Publication Date: N/A

Interpretive Summary: Polycyclic aromatic hydrocarbons (PAHs) are the major source of environmental contamination resulting from petroleum industry. Due to the health hazards associated with the presence of these compounds, about 16 PAHs have been listed as priority pollutants by the United States Environmental Protection Agency (USEPA). In a collaborative research with the University of Puerto Rico, several strains of naturally occurring bacteria have been isolated and characterized for their ability to degrade phenanthrene, a known indicator of pollution resulting from petroleum. In this study, several factors and parameters were studied to determine their effect on the rate and extent by which PAH is degraded. This report provides fundamental knowledge which will be useful for developing the on-site bioremediation procedures for PAHs.

Technical Abstract: Studies were conducted to assess factors that may influence the rate and extent of biodegradation of polyaromatic hydrocarbons (PAHs) in waters of Guayanilla Bay (latitude, 18 deg N; longitude, 66.45 deg W) Puerto Rico. Phenanthrene was used as a model PAHs compound. Both the rate and extent of phenanthrene degradation by natural microbial flora present in seawater samples from Guayanilla Bay were quite slow. Addition of KNO3 as a source of inorganic nitrogen (N) resulted in a 10-fold increase in the rate of phenanthrene degradation within a 125 h period, whereas addition of K2HPO4 as a source of inorganic nutrient phosphorus (P) had no effect. Phenanthrene degradation was strongly inhibited when seawater pH was adjusted to 10.0. Phenanthrene in seawater samples degraded rapidly when first pretreated with hydrogen peroxide (H2O2) and then inoculated with a known indigenous phenanthrene degrading bacterium, Altermonas sp. Pretreatment of phenanthrene with Triton-x-100 had little or no effect on its degradation by the same bacteria, whereas, degradation in samples preheated at 60 deg C was somewhat inhibited.