Scientists are finding more troubling news that the chemical oil dispersants BP used in the Gulf of Mexico to break up its massive Deepwater Horizon oil spill may be doing more environmental damage than good. While previous studies documented how BP’s oil dispersants created giant toxic plumes of dissipated oil that could remain on the Gulf floor for the next century, a new study has found the same dispersed oil is penetrating deep into the sand on shore.
Markus Huettel, a professor in Florida State University’s Department of Earth, Ocean and Atmospheric Science, and Alissa Zuijdgeest, a graduate student at the Swiss Federal Institute of Technology, conducted the study on Pensacola’s beaches after noticing oil-stained sand on the shore there that went down as far as two feet deep.
“The sand was not white,” Dr. Huettel told the Environmental Monitor. “It had this tannish-brown color and if you grab the sand it had this soapy, oilish feeling.”
The researchers tested how both non-treated oil and oil treated with chemical dispersants penetrated the sand by filling two acrylic tubes with sand. In the lab, they poured oil taken from BP’s blown-out Macondo well over some of the samples. On other samples, the researchers poured a mixture of Macondo oil and Corext dispersants and plain sea water.
Analyzing the fluorescent distribution of hydrocarbons in the sand and their chemical properties, the research team discovered that oil mixed with dispersants penetrates the sand much deeper than untreated oil. Additionally, the untreated oil degrades much more slowly and releases more polycyclic aromatic hydrocarbons into the environment.
The introduction of water to the columns to mimic the effect of ocean waves drove the dispersed oil deeper and deeper into the sand. The research team then performed the tests on the beach in real-world conditions and found that the “oil dispersants increased the flux of hydrocarbons into the sediment compared to oil-contaminated water without dispersants,” the Environmental Monitor reported. The researchers also found the water held more polycyclic aromatic hydrocarbons after dispersants were added.
While the levels of polycyclic aromatic hydrocarbons detected were less than EPA threshholds for human health, the chemicals could damage and kill macroinvertebrates in the sand and seep into nearby groundwater. The hydrocarbons could also wash back into the ocean, where it could threaten marine life.
According to the Environmental Monitor, Dr. Huettel said that oil dispersants are probably not the way to go in fighting oil spills even as large as the BP spill because “nature has mechanisms to deal with oil leaking from natural undersea seeps.”
Granted, the seeps are certainly nowhere near the 205 million gallons of oil leaked into the water from the Deepwater Horizon spill but, “I personally think that leaving it alone is the better strategy” Huettel told the Environmental Monitor.