Pesticides, antibiotic-resistant bacteria could be spread by raindrop aerosols

Thursday, January 14, 2016 by: L.J. Devon, Staff Writer
Tags: pesticides, raindrops, aerosols

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(NaturalNews) Rain storms naturally produce aromatherapy and researchers from the Massachusetts Institute of Technology are finding out how. Using high speed, slow motion cameras, the researchers' documented how raindrops hit a surface of the Earth and create aerosols that can be carried through the wind. The aroma-therapeutic phenomenon has been known as petrichor, which is a term for the earthy scent that is released when rain hits dry soil. When water drops hit a surface, tiny air bubbles explode inside, blasting tinier droplets called aerosols into the air where they can be carried by wind.

Lead researcher Cullen Buie compared the action to opening a can of soda. "When you pour a freshly opened can of soda, you notice a fizz above the surface," he said. When the bubbles pop, the fizz becomes an aerosol that sends the smell of the soda to a person's nose.

Pesticides and bacteria can take to the wind when raindrops hit a surface

When rain hits the Earth's surface, it can potentially send aerosols filled with E. coli bacteria or pesticides into the air where they can be carried by wind to unsuspecting people.

The researchers were able to track this phenomenon by applying fluorescent dye to 16 different kinds of soil. Then, they simulated rainfall by dripping water droplets onto each sample. The falling droplets literally picked up the dye from the soil and turned it into aerosols. Using speed as a variable, the researchers found out that light to moderate rainfall had the most dramatic effect. The researchers added that aerosols can travel through the air for miles.

"You would expect pesticides and other contaminants to be dispersed by this mechanism as well," said Buie. This research may provide some reasoning as to why we instinctively take shelter from rain. It might not be because we are getting wet. It could be because our senses are protecting us from pathogenic or chemical aerosols that are kicked up into the wind by rainfall.

In theory, viruses and bacteria could spread through raindrop aerosols, but the researchers are currently working on new experiments to verify how this works to potentially contaminate agricultural crops. They have verified that bacteria on soil surfaces can be dispersed into the wind, but they haven't yet proved that bacteria and pesticides can be splashed into the air off of crops or how these crops catch aerosols from miles away. If proven, this could provide valuable insight into how strains of E. coli spread from raindrop aerosols onto the leaves of leafy greens, ultimately infecting the people who eat them. In San Benito County California a deadly strain of E. coli sickened over 200 people in 2006 and caused at least three deaths. The contamination was thought to be caused by feral pigs. This research may shed new insight on how rain drop aerosols play a part.

Sources:

http://www.thecalifornian.com