Weathering of hydrocarbons in mangrove sediments: testing the effects of using dispersants to treat oil spills

This field study was a combined chemical and biological investigation of the relative effects of using dispersants to treat oil spills impacting mangrove habitats. The aim of the chemistry was to determine whether dispersant affected the short- or long-term composition of a medium range crude oil (Gippsland) stranded in a tropical mangrove environment in Queensland, Australia. Sediment cores from three replicate plots of each treatment (oil only and oil plus dispersant) were analyzed for total hydrocarbons and for individual molecular markers (alkanes, aromatics, triterpanes, and steranes). Sediments were collected at 2 days, then 1, 7, 13 and 22 months post-spill. Over this time, oil in the six treated plots decreased exponentially from 36.6 +/- 16.5 to 1.2 +/- 0.8 mg/g dry wt. There was no statistical difference in initial oil concentrations, penetration of oil to depth, or in the rates of oil dissipation between oiled or dispersed oil plots. At 13 months, alkanes were >50% degraded, aromatics were similar to 30% degraded based upon ratios of labile to resistant markers. However, there was no change in the triterpane or sterane biomarker signatures of the retained oil. This is of general forensic interest for pollution events. The predominant removal processes were evaporation (less than or equal to 27%) and dissolution (greater than or equal to 56%), with a lag-phase of 1 month before the start of significant microbial degradation (less than or equal to 7%). The most resistant fraction of the oil that remained after 7 months (the higher molecular weight hydrocarbons) correlated with the initial total organic carbon content of the soil. Removal rate in the Queensland mangroves was significantly faster than that observed in the Caribbean and was related to tidal flushing. (C) 1999 Elsevier Science Ltd. All rights reserved.

Immediate ecotoxicological effects of short-lived oil spills on marine biota.

Marine environments are frequently exposed to oil spills as a result of transportation, oil drilling or fuel usage. Whereas large oil spills and their effects have been widely documented, more common and recurrent small spills typically escape attention. To fill this important gap in the assessment of oil-spill effects, we performed two independent supervised full sea releases of 5 m(3) of crude oil, complemented by on-board mesocosm studies and sampling of accidentally encountered slicks. Using rapid on-board biological assays, we detect high bioavailability and toxicity of dissolved and dispersed oil within 24 h after the spills, occurring fairly deep (8 m) below the slicks. Selective decline of marine plankton is observed, equally relevant for early stages of larger spills. Our results demonstrate that, contrary to common thinking, even small spills have immediate adverse biological effects and their recurrent nature is likely to affect marine ecosystem functioning.

Bioremediation of oil spills

Due to the increasing demand of petroleum everywhere, and the great amount of spills, accidents and disasters, there is an urgent need to find an effective, non-cost and harmless method to clean up the affected areas. There are microorganisms in nature (bacteria and fungi, mainly) that feed on hydrocarbons and transform them into others harmless chemical substances. These bacteria produce enzymes that degrade oil very effectively. This natural process can be accelerated by adding more bacteria or providing nutrients and oxygen to facilitate their growth, which is called ―bioaugmentation and biostimulation. Through this project we discover that these processes can be affected by different factors making difficult the biodegradation execution and opening a gap between the laboratory experiments and the real cases. Therefore, there is much remain to be done and a lot of study ahead to make this technique available in a great scale.

Selected methods for detecting and tracing hazardous materials spills /

Mode of access: Internet.

Laboratory investigation of residual liquid organics from spills, leaks, and the disposal of hazardous wastes in groundwater /

Mode of access: Internet.

Chemical shoreline cleaning agents for oil spills : update state-of-the-art on mechanisms of action and factors influencing performance /

"EPA contract no. 68-C8-0062, Work assignment no. 3-48, SAIC project no. 01-0895-03-1000."

Emergency spills research strategy 1980-1984 /

Mode of access: Internet.

Hazardous material spills and responses for municipalities /

Mode of access: Internet.

CAM-4, a portable warning device for organophosphate hazardous material spills /

Mode of access: Internet.

Hazardous material spills : a documentation and analysis of historical data /

Mode of access: Internet.

Development of a kit for detecting hazardous material spills in waterways /

Mode of access: Internet.

Study of detection, identification, and quantification techniques for spills of hazardous chemicals /

Sponsored by the Coast Guard, Office of Research and Development, and the Environmental Protection Agency, National Environmental Research Center, Remote Sensing Branch.

Disposal systems and techniques for oil and hazardous chemicals recovered from marine spills /

Final report, February 1979.

A summary of immediate telephone notification requirements for spills or sudden releases of chemicals and oils in Illinois.

"Version 2.0."