Sunlight can help dissolve oil into seawater, surprising even scientists

Last updated on February 26th, 2022 at 01:16 pm

Water and oil are naturally antipodals, which means that oil does not dissolve in water; it just floats over the surface. Due to this natural phenomenon, oil spills have been the greatest of disasters, polluting water bodies and proving hazardous for the environment. 

But what if there is a natural solution to this problem! 

Scientists have observed that sunlight can effectively dissolve the oil into the ocean. 

A team of researchers from Woods Hole Oceanographic Institution (WHOI) intend to figure out where much of the oil from the 2019 Deepwater Horizon oil spill wound up. It was one of the largest spills in US history, where almost 210 million gallons of crude oil was spilled into the Gulf of Mexico. It even caused 11 deaths. 

To the surprise of these researchers, about 17 % of this floating oil seems to dissolve into the water. It is nothing short of a miracle, as this has never happened before. After studying closely, they concluded that sunlight dissolved some oil into the water. 

Daniella Haas Freeman, a joint program student at WHOI, said, “If this sizable fraction of oil is being transformed by sunlight and is dissolving into seawater, that might mean that less oil is ending up in other places, like sensitive coastal ecosystems. On the other hand, we have to consider the impacts of the compounds on marine organisms before we can decide if the net result is positive or negative,”

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Researchers explained that when the sunlight falls on the spilled oil, it generates chemical reactions that transform it into another substance. Photo-oxidation is one such chemical process that degrades the oil surface due to the combination of oxygen and sunlight. It affects the solubility level of oil in the water.

Scientists have already been trying the method called photo-dissolution for over 50 years. They expose the substance to light and generate the water-soluble substances from the crude oil. However, they never used this process to evaluate any past oil spills. But they used the custom-built light-emitting diode (LED) reactors to study various effects of the different kinds of lights (like, visible light, ultraviolet) on the oil surface. 

They conclude that oil thickness is of utmost importance when these chemical reactions occur. The oil spill location also affects the results, as at some places, there’s a greater risk of oil spilling than others. Wavelengths of light equally matter in this process. Researchers observed that the longer the wavelength, the lesser oil it dissolves as it is more scattered by water than the short wavelength. 

The studies by WHOI’s researchers could prove to be a boon for the environment in case of oil spills. If so, the natural resource, sunlight, can spare the need of any other custom-built lights. Moreover, it could resolve many issues pertaining to the maritime oil-spill disasters and save marine life to a greater extent. 

At present, Freeman and the team are researching the impact of sunlight on oil spills even profoundly.

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