Let’s talk plastic

Jimena B. Pérez-Viscasillas, University of Puerto Rico


In a recent article published by The Conversation, researcher Richard Sharpe discusses his work on male reproductive efficiency and how it might be affected by phthalates. Phthalates are plasticisers, compounds added to plastic materials to make them more flexible.  “Plasticisers leach out of the plastic over time” Sharpe writes. “This is why if you use the same plastic water bottle over a long period it will eventually become brittle and break – indicating that you have drunk all of the plasticisers that leached out.”

Fig. 1  Plastics aren’t the only products with phthalates. These compounds can also be found in fragrances, personal care products, etc. (Taken from University of Michigan Formative Children’s Environmental Health and Disease Prevention Center


What could this mean for our health? Many different studies have been conducted to find out how these compounds might be affecting our bodies. Sharpe specifically focuses on how they might affect the male reproductive system. He argues that, because the available data on the subject is so variable, it is not yet completely conclusive whether phthalates are indeed the cause of lower male fertility.

What we do know, however, is that phthalates have been found to disrupt the production of some hormones in the body. Because hormones are the body’s chemical messengers, not having them able to deliver their messages to tissues properly could mean trouble for one’s health. One such case is that of prostaglandins, the hormone I’m looking at in this summer’s research. Prostaglandins are hormones that regulate inflammatory responses in the body. When you prick your finger and see it swell up, part of what you’re observing is due to prostaglandins doing their job, allowing more blood and immune cells into your tissue. Prostaglandins play major roles in the immune and reproductive systems. Therefore, it is hypothesized that if a pregnant woman suffers from hormonal inhibition because of exposure to phthalates, this could have long-term health effects on her baby too.

Fig 2. Human embryo. (Image taken from BBC)

Sharpe asks this research question in his article as well. However, part of the reason why effects of contaminants on human health are so difficult to research is precisely because exposure to them is so common among human populations. As he points out, “this means we don’t really have an unexposed group (“control”) against which to compare.” Luckily, we humans aren’t the only organisms around. Studying other species (such as, say, gators and chickens…) allows us to better understand these possible hazards.  Finding evolutionary relationships between us and sentinel species is an essential step towards understanding just what these phthalates and many other contaminants are up to in our bodies.

To learn more about phthalates, click here. For more about my research, stay tuned. Later, gators!


This research is made possible thanks to the Hollings Marine Laboratory, the Medical University of South Carolina, the College of Charleston and funding by NSF through the Fort Johnson REU program.

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Kristensen, David M. (2011). Many Putative Endocrine Disruptors Inhibit Prostaglandin Synthesis.  ENVIRONMENTAL HEALTH PERSPECTIVES. Vol.119 No. 4: 534 – 541.

Milnes MR, Guillette LJ Jr. Alligator Tales: New Lessons about Environmental Contaminants from a Sentinel Species; BioScience 2008; Vol. 58 No.11 doi:10.1641/B581106

Sharpe, Richard. “Are plastics making men infertile?” The Conversation 25 Jun. 2015. Web 29 Jun. 2015.

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