Persistent organic pollutants (POPs) are carbon-based chemical substances that remain in the environment over a long period of time. They can be transported over long distances and can bioaccumulate through the food web, storing in fatty tissues of living organisms. POPs are widely distributed over large regions around the globe due to human activity. Effects of POPs includes damage to the nervous system, reproductive system damage, immune system damage, cancer, and allergies (1). Some POPs are also endocrine disruptors, damaging the hormonal system leading to damage within the reproductive system as well as the offspring. Common POPs can include crude oil and petroleum refined products (gasoline, motor oil, kerosene) polyaromatic hydrocarbons (from coal power plants, manufacturing gas plants), PCBs (polychlorinatedbiphenyl ethers), pesticides/ insecticides/ herbicides, detergents, plastics, and alcohols (1).
On April 21st, 2016 Emily Gertz from Alternet posted an article titled “How Eating Tuna Can Weaken Your Immune System”. This article was based off of the work lead by Amro Hamdoun. Starting off, the article states that eating any seafood that has been tainted with long-lasting environmental contaminants can weaken the body’s defense system. Emily talked about how the study tested how the exposure to 10 POPs can impact an important protein, P-gp, in animals (3). The purpose of P-gp is to eject toxins from the body but the researchers found that the 10 POPs can weaken this protein’s protective role. Throughout the article Emily provides quotes and facts directly from the peer reviewed article. She states what the purpose of the study was and the conclusions it made. She also gave some background information on POPs at the end of her article.
The peer reviewed article titled “Global marine pollutants inhibit P-glycoprotein: Environmental levels, inhibitory effects, and cocrystal structure” focused on P-glycoprotein (P-gp) and how 10 different POPs interact with the drug outflow transporter, P-gp (2). The researchers identified specific types of organochloride pesticides, polychlorinated biphenyls, and polybrominated biphenyl ethers which inhibit P-gp in organisms. P-gp is a key protein for xenobiotic elimination in all animals. Within the discussion section the researchers described that the P-gp along with P450 is expressed on apical plasma membranes at sites of toxin uptake such as the intestine (2). The inhibition of P-gp by POPs can cause a decrease in critical cellular defense. P-gp protein was extensively studied with the interaction of inhibitory pollutants, polybrominated diphenyl ether (PBDE)-100 (2). This provided the first view of a pollutant binding to a drug transporter. The structure of P-pg also reviled a high degree of conversion within POPs binding residues. They determined the environmental levels of these POPs in yellowfin tuna from the Gulf of Mexico. Primarily tuna was studied because it is one of the most exported fish in that area. The study concluded that there is an inhibition of the transporters by POPs found in fish (2).
I feel that Emily did a good job stating the facts and getting to the point of the peer reviewed article but she did leave out many other important facts that the study concluded that she did not include. I wish she would have talked about solving the cocrystal structure of P-gp bound to a pollutant. Also, I believe that Emily should have focused more on P-gp and its inhibition from POPs since this was the main focus of the study. I did like that she included direct quotes from the peer reviewed article and that she did give some further information that was not stated in the article as well including links to other articles involving the same topic. Overall, I would rate this article a 7/10 for the reasons previously stated.
1) "The 12 Initial POPs
under the Stockholm Convention." Stockhold Convention. N.p., n.d.
Web. 12 Nov. 2016. <http://chm.pops.int/TheConvention/ThePOPs/The12InitialPOPs/tabid/296/Default.aspx>.
2) Nicklisch,
Sascha, Steven Rees, Aaron McGrath, Tufan Gokirmak, Lindsay Bonito, Lydia
Vermeer, Cristina Cregger, Greg Loewen, and Amro Hamdoun. "Global Marine
Pollutants Inhibit P-glycoprotein: Environmental Levels, Inhibitory Effects,
and Cocrystal Structure." Science Advances 2.4 (2016): n.
pag. Global Marine Pollutants Inhibit P-glycoprotein: Environmental
Levels, Inhibitory Effects, and Cocrystal Structure | Science Advances. 15 Apr.
2016. Web. 14 Nov. 2016. <http://advances.sciencemag.org/content/2/4/e1600001.full>.
3) Gertz / TakePart, Emily J. "How Eating Tuna
Can Weaken Your Immune System." Alternet. N.p., 21 Apr. 2016. Web. 12 Nov. 2016.
<http://www.alternet.org/food/how-eating-tuna-can-weaken-your-immune-system>.
It seems to me that the Alternet piece was reaching for conclusions a bit. I am not sure where the author found such strong conclusions about weakened immune systems, but I don't think it was appropriate to draw such a strong conclusion without bringing in more references.
ReplyDeleteThanks for the feedback Aubrey. I agree completely. The peer reviewed article mainly focused on how the protein P-gp is influenced by POPs, but they never related this to the tuna they were testing. Im guessing she implied that once people consumed the fish they would have weakend immune systems. But you are correct, she shouldn't have jumped to conclusions without evidence.
DeleteVery interesting topic, Lindsey! I would have appreciated if Emily would have included a more detailed discussion of some of the sources of POPs. For example, I don't think the most people know that most furniture is coated with polychlorinated biphenyl-containing flame retardants that contribute greatly to the issues discussed in this article. I think giving the common reader more information about how this problem relates to their everyday life (as in how they might unknowingly contribute to it and be affected by it) is important and something Emily could have done better.
ReplyDeleteThanks for the feedback Liz. I also agree with that. These online articles should be more informative for the public in the sense that yes, POPs can be found in your food but here are some other sources etc. It is a little frustrating when articles are posted like this because it is only showing one source while there hundreds of others that should be addressed.
DeleteNice post Lindsey! This is a really interesting topic. These organic compounds have always been directly related to the formation of certain cancerous diseases. However, it is surprising that they can also alter the immune and hormonal system. I´m really concerned about this issue because in my country, Ecuador, the oil activity in coastal zones is very common and we are one of the leading exporters of tuna in the world. I propose that for future studies they should evaluate these compounds in different marine species (Pelagic and Benthic).
ReplyDeleteThanks for the feedback Maria! I was surprised as well to find out how much damage POPs can do to the body as well. And yes, it is an increasing problem but I am glad more people and researchers are putting in more work to better understand POPs and the impacts they have on the environment. Also the impacts physiologically with the human body.
DeleteThe authors of the journal article claim that an "environmentally relevant" mixture of inhibitors impairs the function of P-gp. But they don't actually relate the amount of these inhibitors in the fish to the amount of fish people actually eat on average. Obviously POPs are an issue and we probably should not be eating them, but I think that including this in their research would be more convincing to policy makers.
ReplyDeleteThanks for the feedback Aubrey! I noticed that as well which was interesting. It also made the article posted by Emily not as credible, another flaw with her article. I believe the researchers were trying to relate the work they had done with P-gp and POPs to human health.
DeleteI'm really glad to see you did an article on POPs. They are a big contaminant class to tackle, and it seems like it's always a "win-lose" situation when it comes to their discovery, usage, and subsequent transfer into the environment. For example, aqueous film forming foam (AFFF) is a highly efficient fire suppressing agent that was often used in the military, but a substitute is now being sought after the discovery of its persistence and bioaccumulative nature. Another example is the use of CFCs as very effective replacement to other toxic refrigerator coolants, but we know from class that it got phased out because it was an ozone-depleting chemical.
ReplyDeleteI totally have to agree with Aubrey's comment above and it makes me very skeptical of papers on this type. I love eating fish and in particular really enjoy eating some tuna. There are concerns with eating fish, like mercury levels, but we really have to consider the amount of fish consumed and the concentrations of these contaminants. What concentration of POPs is needed to actually hinder the immune system in a health adult and how much fish would need to be consumed to achieve that concentration? Coastal people who rely on fish as there primary source of protein may need to take precautions but for many of the people consuming these exported products there may be little to no real concern.
ReplyDeleteI think the peer reviewed paper is ok in that it is beginning the research in this area. I am a little more concerned about the popular media article because I am concerned they are simply trying to use fear to discourage people from eating fish products and I think this is boarder line wrong.
Thanks for your feedback Daniel! I agree with you that the article is trying to use fear to inform the public. There needs to be more studies to further explain how much POPs in the body would actually cause harm to the immune system. How much P-gp needs to be inhibited to cause significant impacts needs to be focused on more.
DeleteNice post! I agree with Dan. I think that the popular media article is making some not necessarily warranted general statements. Rather than encouraging people to think about why these issues are happening, the article is focused on telling people to just avoid fish. The peer reviewed study should be an indicator that we need to start considering how to fix this issue, rather than tell us to simply stop eating tuna or other contaminated food sources. With coastal communities depending on this food source so heavily, for both their economy and livelihood, it seems like more popular media articles should be urging people to look for change, not just ignore problems. Further, it would be interesting if the mercury levels of these fish would have also been examined. Are there any links between theses two types contaminants?
ReplyDeleteThanks for the feedback Annabel! Ive been looking online and there have been many studies to detect mercury and POPs concentrations in various species including humans. But i'm not entirely sure if they have any impacts on one another. I'm sure the accumulation of both of these contaminants would cause more harm than just one or the other in the body.
DeleteGood job, Lindsey! For me, it turns out to be a quite inspiring and refreshing topic because I have always been interested in food security in daily life. I was shocked to hear that eating tuna can exert negative impacts on our immune systems. However, though the article demonstrated something about the specific protein P-gp which can eliminate xenobiotic contamination, I still fell confused about one thing that is tuna the specific fish be effected by POPs? Or actually all of the fish will be influenced by POPs, then the title of the article will be a little bit misleading and exaggerating.
ReplyDeleteI agree with you and thanks for the feedback! Yes the article is misleading because the author Emily makes assumptions on what the peer review article is trying to convey. the peer reviewed article is mainly on the discovery of the cocrystal structure P-gp and how POPs bind to it. They also measured the amounts of POPs in a sample of tuna making it environmentally relevant. There was no real correlation or data shown that eating fish causes immune depression.
DeleteI agree with the previous posts that the article is misleading. I don't think that avoiding fish because they have POPs in them is going to help people's immune systems. People are already exposed to background levels of these chemicals all the time. It would be interesting if the researchers did a study comparing people who eat fish regularly with those who do not and trying to figure out if there is actually a link between eating these fish and P-gp expression.
ReplyDeleteThe Alternet was pretty bad. The only thing I got from it was not to eat tuna. This is the problem with these types of articles, people without critical thinking abilities will read it and never eat tuna (or any fish). Most of the fish we eat comes from fish farms does it not? Are there any new regulations on fisherman trying to sell seafood from the Gulf as a result of the Gulf oil spill? It would be interesting to see if there are such regulations.
ReplyDeleteThanks for the feedback Rory. There are commercial and recreational regulations that were put into place for fishing in the gulf. These regulations state when you can fish certain types of fish, what types of fish you can keep, and how many you can keep. permits are required as well for all fishers. Now we are focusing on remediation and restoration of the gulf waters.
DeleteReally nice post, Lindsey! I definitely agree with some of the previous posts about the Alternet's dubious reporting. I think that, even though this is some new research, it would be interesting to see how these POPs effect other marine organisms, apart from tuna, and whether the reaction would be as severe in larger animals, or in the people who are consuming these protein sources.
ReplyDelete