Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Low concentrations of oxygen and nutrients slowing biodegradation of Exxon Valdez oil

The combination of low concentrations of oxygen and nutrients in the lower layers of the beaches of Alaska's Prince William Sound is slowing the aerobic biodegradation of oil remaining from the 1989 Exxon Valdez spill, according to researchers at Temple University.

Considered one of the worst environmental disasters in history, the Exxon Valdez spilled more than 11 million gallons of crude oil into Alaska's Prince William Sound, contaminating some 1,300 miles of shoreline, killing thousands of wildlife and severely impacting Alaska's fishing industry and economy.

In the first five years after the accident, the oil was disappearing at a rate of about 70 percent and calculations showed the oil would be gone within the next few years. However, about seven or eight years ago it was discovered that the oil had in fact slipped to a disappearance rate of around four percent a year and it is estimated that nearly 20,000 gallons of oil remains in the beaches.

The researchers, lead by Michel Boufadel, director of the Center for Natural Resources Development and Protection in Temple's College of Engineering, have been studying the cause of the remaining oil for the past three years.

Their study, "Long-term persistence of oil from the Exxon Valdez spill in two-layer beaches," was posted Jan. 17 in advance of publication on Nature Geoscience's Web-site (

Boufadel said the beaches they studied consisted of two layers: an upper layer that is highly permeable and a lower layer that has very low permeability. He said that, on average, water moved through the upper layer up to 1,000-times faster than the lower layer, and while both layers are made up of essentially the same materials, the lower layer has become more compacted through the movement of the tides over time.

These conditions, said Boufadel, have created a sort of sheltering effect on the oil, which often lies just 1-4 inches below the interface of the two layers.

Boufadel said that oxygen and nutrients are needed for the survival of micro-organisms that eat the oil and aid in aerobic biodegradation of the oil. But without the proper concentrations of the nutrients and oxygen along with the slow movement of water, anaerobic biodegradation is probably occurring, which is usually very slow.

Boufadel, who is also chair of the Department of Civil and Environmental Engineering at Temple, said that an earlier study, published in 1994, had already established a low concentration of nutrients was affecting the remaining Exxon Valdez oil.

He said that because of Alaska's pristine environment, you would expect to find a low concentration of nutrients and this recent study confirmed the earlier findings. What Boufadel and his team found was, on average, that the nutrient concentration in the beaches was 10 times lower than what is required for optimal aerobic biodegradation of oil. They also found that the oxygen levels in the beaches are also insufficient to sustain aerobic biodegradation.

Using groundwater hydraulic studies, the researchers found that the net movement of water through the lower layer of beach was outwards, so it is preventing oxygen from diffusing through the upper layer to where the oil is located.

"You have a high amount of oxygen in the seawater, so you would like to think that the oxygen would diffuse in the beach and get down 2-4 inches into the lower layer and get to the oil," said Boufadel. "But the outward movement of the water in the lower level is blocking the oxygen from spreading down into that lower layer."

Boufadel and his team are now exploring ways to deliver the much needed oxygen and nutrients to the impacted areas in an effort to spur aerobic biodegradation of the remaining oil.

The study was funded by a grant from the Exxon Valdez oil Spill Trustee Council.

Preston M. Moretz | EurekAlert!
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

nachricht Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>