Hydrocarbon Distribution and Weathering Characteristics at a Tropical Oil Spill Site

Abstract

A study was performed on the state of an oil spill site on the southwest coast of Puerto Rico. The location of the study was Bahia Sucia, the site of the Zoe Colocotroni spill of 17 March, 1973. Particular attention was given to the weathering characteristics of the stranded oil remaining at the sites and to the presence of biogenic hydrocarbons in the sediments. High resolution gas chromatography of the aliphatic and aromatic fractions of the sediment hydrocarbons was used to distinguish the types of hydrocarbons present and their distribution. It was observed that oil weathers much more rapidly in a tropical environment as compared with spills in temperate areas. Even in the most heavily impacted areas, the Zoe Colocotroni oil had weathered practically to the point of being tar. It was also observed that a tropical site has a significant chronic input of hydrocarbons from both natural and anthropogenic sources. Gas chromatograms of extracts of leaf waxes from live mangroves compared with biogenic hydrocarbons observed in the sediments. Tar-balls also account for a significant fraction of the hydrocarbon burden in the sites studied. The conclusion is that a tropical area has the potential for making a much more rapid recovery from an oil spill than a temperate one. Moreover, in assessing the effects of a tropical oil spill, care must be taken to distinguish the relative contribution to the total hydrocarbon burden in a spill area by oil, pelagic tar, and biogenic sources.

Ecotoxicology of tropical marine ecosystems

“…The anaerobic conditions and low redox potential values found in mangrove sediments are known to be unfavorable for the biodegradation of hydrocarbons [58], and substantial concentrations of hydrocarbons remain in mangrove sediments 10 to 30 years after spills [59,60]. Three years after the Zoe Colocotronis spill in Puerto Rico, soil samples from the mangrove community had up to 80,000 ppm extractable hydrocarbons [61]. Mangroves can translocate aromatic hydrocarbons into their tissues [46], and the toxic components of retained oil continue to cause sublethal effects, including reduced productivity, lower rates of litter production, and lower seedling survival [62].…”

The natural petroleum hydrocarbon background in subtidal sediments of prince william sound, Alaska, USA

“…There are three major hydrocarbon types: (1) petrogenic hydrocarbons related to crude oil and its refined products; (2) biogenic hydrocarbons generated by biologic or diagenetic processes; and (3) pyrogenic hydrocarbons generated by high temperature processes [4], including forest fires and fossil-fuel combustion. For example, Page et al [5] documented multiple sources of petroleum and biogenic hydrocarbons in the Amoco Cadiz impact zone; mangrove leaf waxes [6] were shown to be a major source of biogenic hydrocarbons in a tropical spill site; and Page et al [2] identified numerous hydrocarbon sources in Prince William Sound subtidal sediments, including pyrogenic polycyclic aromatic hydrocarbons (PAHs) primarily associated with sites of past or current human use (see also Bence et al [7]), weathered Exxon Valdez oil residues from subtidal areas close to some heavily oiled shorelines, and a regional background of oil-seepderived petroleum distributed throughout the seafloor sediments in the sound. The identification of this regional petroleum background was subsequently confirmed by benthic sediment studies conducted by others in 1993 [8].…”

Impact of oil pollution on living resources

“…Nadeau and Bergquist (1977); Page et al (1979) Getter et al (1981) Lasday et al (1981 Reports in the literature of oil pollution damage to mangroves include the following, given in Table 3. Large trees not defoliated at this stage.…”