I call it the “invisible pollution”.
Microplastic are plastic particles smaller then 5mm. It means that only bigger fragments are visible through human eyes; the smaller ones can be visible only at the microscope. But with the term “invisible pollution” I mean also an other side of this problem.
Introducing my study
My name is Martina Capriotti, I’m an Italian marine biologist studying pollution in the sea since some years. As part of the founder team of the Hydrosphere Association I want to provide my contribute to help our oceans. The project I’m currently conducing, thanks to a National Geographic and Sky Ocean Rescue grant, focuses on evaluating the presence and the effects of anthropogenic chemical contaminants attached to the microplastics’ surface, trying to fill up the big gap of knowledge on microplastic biological effects.
About the contaminants
When I talked about anthropogenic contaminants, I referred to chemical compounds that can have a toxic effect on life and can persist in the environment. Their common definition is : POPs Persistent Organic Pollutants. They have the ability of accumulating inside lipid tissues, through a process defined as “bioaccumulation”; in this way they enter the food web raising the concentration at each higher level, through a process defined as “biomagnification”.
Microplastic particles attract POPs in the aquatic environment, as they have a very low affinity for water. Several studies demonstrated how these chemicals create bonds with plastic polymers in the lab.
Other studies (like mine) found a great variety of contaminants on the surface of microplastics collected from the field.
Microscope image: blue microplastic mm. 3,5
© 2019 Martina Capriotti
Seems that once ingested, microplastics can release these contaminants inside the digestive tract of the animal and let them be absorbed at gut level. Very few data exist on this specific topic at the moment, but it could possibly be a pollutants source.
Consequences in the body
Which kind of consequences contaminants in the water can provoke?
A part from a stress status, detectable at biomolecular level, many compounds are able to mimic the endogenous hormones, acting in the organism instead of them.
So they can bind cellular receptors, that are generally bound by endogenous hormones; as consequence they activate some pathways inside the cell, in an enhanced way or also when the hormone is not present in that moment.
We can detect other kind of effects at development, reproduction or behavioral levels.
Martina Capriotti – PhD Life and Health Science
Hydrosphere Association Scientific Director