Dolphins Are Being Poisoned by Their Mother's Milk, Scientists Warn
Dolphins Are Being Poisoned by Their Mother's Milk, Scientists Warn
News article: https://www.newsweek.com/dolphin-babies-toxic-chemicals-mother-milk-1841219
Scientific article: https://www.sciencedirect.com/science/article/pii/S0048969723065154?fr=RR-2&ref=pdf_download&rr=823a4a1b4a132a99
For my blog post, I chose the news article “Dolphins Are Being Poisoned by Their Mother’s Milk, Scientists Warn” by Jess Thomson at Newsweek. This news article was published November 6, 2023. This news article draws most of its material from the scientific article, “The dynamics of persistent organic pollutant (POP) transfer from female bottlenose dolphins (Tursiops truncatus) to their calves during lactation. This research was carried out by a group of scientists at different marine wildlife organizations like the Northwest Fisheries science center and U.S. Navy Marine Mammal Program.
The scientific article, published October 18, 2023, looks into multiple aspects of persistent organic pollutant (POP) transfer from female delphinids to calves. POPs are organic compounds with high lipophilicities that build up in the blubber of marine mammals, specifically predators who consume prey with high trophic levels. These contaminants can be passed from mother to offspring during the gestation period and during lactation. To understand the transfer of POPs from female dolphin to calf, placenta and blood and milk samples were analyzed. As POP levels in the blood of marine mammals correlate to the concentration of POPs in the blubber, they used the data from blood serum samples to reflect the concentrations of POPs that would be found in the blubber. They measured the concentrations of PCPs, PBDE congers, DDTs, and several other POPs in the placenta collected after birth and milk and blood serum samples from mother/calf pairs at time periods from birth to ~15 months post-partum (the duration of the nursing period in wild bottlenose dolphins). They also measured the thickness of the blubber at 3 sites in all female dolphins to understand how blubber stores in mother/calf pairs change over time and if this any effect on the overall POPs transferred. These findings were grouped by the history of the dolphin (age and reproductive history).
Fig. 1. Milk sum POP concentrations in adult female bottlenose dolphins during the lactation period. Female numbers are based on age, from oldest (Fem 1) to youngest (Fem 3).
Blubber thickness was measured using ultrasound technology. They found that, despite other dolphin species mobilizing fat during lactation period, the female bottlenose dolphin blubber thickness remained stable over the 15-month lactation period. This suggests that contaminant transfer patterns will vary across marine mammal groups, and studies like this are needed across several different marine species to understand the role of blubber in species lactation. Sample collection included taking milk and blood serum samples as soon as possible after calf birth and at 3 month intervals (month 6, month 9, and month 15 approximately post-partem). GC-MS and TLC-FID were used to analyze POP concentrations in these samples. The data showed the trends in concentrations of contaminants in placentas, milk, and blood serum were as follows: ∑PCBs and ∑DDTs were found in highest concentrations and HCHs were consistently found in lower concentrations in these samples. Although POP concentration varied from individual to individual, overall, milk POP levels decreased over time, with the multiparous (birthed calves before study) female displaying lower POP concentrations than primiparous (birthed their first calf in study) females. They sampled a primiparous dolphin and found that her PCB and DDT concentrations dropped >80% in the first 89 days post-partem compared to the PCB and DDT concentrations determined pre-partum. An interesting result that was found in this study was that first time mothers hold higher amounts of contaminants and transfer larger amounts of POPs to their calves than dolphins that have given birth before the study. While the POP concentrations in the mothers were found to decrease during the lactation period, the concentrations of POPs in the calves increase, resulting in calves having higher concentrations of POPs than their mothers by the end of the 15 month period. These high levels of contaminants entering the body of calves could have detrimental effects on their early neurological development.
The news article begins by contextualizing the most alarming discoveries of the study, framing the findings as incredibly concerning. I believe they opened their article with these findings for the shock factor, using the alarming results to draw readers in. Then the author takes a step back to discuss what POPs are, how they enter the environment, and how bioaccumulation results in high contaminant concentrations in the blubber of dolphins. These topics were not discussed in great detail in the study. By doing this, the news article author makes this research more accessible to a larger audience. The news article does do a good job explaining the finding that POPs in female dolphins decrease as the concentrations of POPs increase in the calves during the lactation period. The author then lists all the chemicals that were quantified during the study. Normally I would appreciate an author going deeper into the breadth of what was analyzed in the study, however this author does not even include what were the major and minor contaminants found in the samples. Unless a reader has read the scientific article, they would be left assuming that all these chemicals were found in high concentrations in the study samples. The news article then changes topics, saying that the finding in this study could also explain why high numbers of Southern Resident orca calves have been dying a year post-partum. Nowhere in the scientific article are orca whales mentioned, and the hyperlinked source goes to another Newsweek article (not a scientific article or trusted source). In fact, the study makes it a point to discuss how these results are specific to bottlenose dolphins and how these studies are needed across a variety of taxa. This section of the news article seems unnecessary.
Overall, I would rank the news article a 5/10 as they did not accurately discuss the findings of the study and framed specific information to lure in readers. The results they discuss can be misleading if the reader does not read the scientific article as well. It seems there is no real organization to how the news article author discusses the findings of the study, as the author ends up repeating the effects of bioaccumulation 4 times and reiterates information about the negative health effects of toxins in calves. Additionally, the information about the orcas seems thrown in at the end, with no clear connection to the actual study discussed.
I honestly think that the news article could have received a lower score than what you gave it. The fact that it didn't actually go into detail on any specific concentrations, or include any helpful diagrams shows that they did not care much to accurately and honestly present the scientific information. Additionally, it seems ridiculous that the author would try to broaden the scope of the issue to orcas when the scientific paper specifically states how the results of the study cannot be applied to other marine animal populations because of differences in blubber accumulation and loss.
ReplyDeleteHi Giana, I completely agree that this article deserves a score lower than 5. I keep reflecting on how this article is way too broad and there is not much the reader would take away from it as it did not include key values of POP concentrations as well as other important findings of the study. I was pretty confused on the message that this article was trying to get across to this readers by including the snippet about orca whales, where they trying to give the impression that these findings are directly translatable to orcas as well?
DeleteThis is really interesting research that seems pretty difficult to carry out. If I didn't take a look at the Methods, I would have assumed the team sought out wild dolphins to take their samples. It's pretty fortunate for the study to have dolphins kept in open water enclosures, and I feel like the news article might have benefitted from a quick mention of this. Maybe they omitted this part so they didn't have to get into a discussion about treatment/care of the animals, as I'm sure a good deal of readers would be concerned about this.
ReplyDeleteHi Zach, I have to agree that they might have omitted information about the source of dolphins so they wouldn't need to elaborate on how controlled the conditions of this study were. The scientists who performed this study even went as far to test the POPs in the octopi and other fish they were feeding mothers and calves during this study to ensure the POPs were not coming from their food source. There were a lot of cool techniques that were used to carry out this study, and I am disappointed these were not discussed at all in the news article.
DeleteThis is a really interesting study, I agree with your rating for this article. I think coming to the conclusion that this sort of POP accumulation could be responsible for the death of orcas a year after birth is a very large jump, especially considering the study specifically mentioned this was a very species specific finding. In regards to the study, I see why they used blood POP levels as a stand in for measuring POP levels in blubber, as to not have to take a biopsy from the mothers, but I don't link this is a good approximation. I could be mistaken here, but to my understanding, the plasma of blood that carries all other constituents such as blood cells is mostly water, so it seems to me and POP would be relatively quickly sequestered into fatty tissues that are more hydrophobic.
ReplyDeleteHi Kelsey, I think this is a really good point, and something that was not explicitly explained in the study. They put a link to a study from the Marine Pollution Bulletin called "PCBs and chlorinated pesticides in clinically healthy Tursiops truncatus: Relationships between levels in blubber and blood" which studied the relation between concentrations of POPs in the blood and in the blubber of bottlenose dolphins. You are totally correct that these POPs will have higher lipophilicities and thus be in blubber in higher concentrations. This study was able to use the concentrations found in blood and blubber and observed there was a positive relationship between the two (not that they are the same). Using this method, this study determined the concentrations of POPs in blood and were able to extrapolate what the concentrations would be in blubber.
DeleteI believe that this news article didn't really do a great job following the actual scientific article. While it is important to cater to non-scientific readers as a news organization, it is also important that it doesn't just go more towards fear-mongering without brining in specific data. I mostly agree with the 5/10 rating, if not even a 4/10. I also find that the methods section of the scientific study needs to be discussed more. Some of the sample preparation doesn't make too much sense without some more context.
ReplyDeleteHi Roland, upon reflection I believe that this article deserves a rating lower than 5. I have a hard time understanding the purpose of this news article other than presenting data in a misleading way to generate fear in readers. The news organization itself is very sketchy. The website itself has many formatting issues, especially the headers on the tabs at the top of the page. This makes the articles coming from this website seem untrustworthy.
DeleteI agree with your assessment, as it is clearly disappointing that the author hesitated to go into detail on specific and relevant data from the study, as well as include diagrams or charts that could help the reader understand the findings of the study. I don't appreciate articles that don't portray the research from the scientific study in an adequate manner; not everyone reads scientific papers or has access to them. So, it would be helpful to those who like to actually learn from news articles or the web if the author could discuss more specifically and accurately the results from the scientific study - especially, for example, the specific concentrations, as well as the major and minor contaminants, as you've noted. I agree with your analysis of what the article does well, but it is clear that a lot could be better.
ReplyDeleteHi Nick, I too feel it is disappointing when articles do not go represent science in a way the audience can understand. This, I believe, has a twofold effect: (1) disappoints readers who know a thing or two about science, and (2) can potentially mislead readers into misunderstanding the research of the study supposedly being reported. And that is what I think this article is doing. By improperly representing the data of the study, they can lead readers to interpret the results of the study incorrectly.
DeleteI agree that the article's potential is hindered by a lack of clarity and cohesion in presenting the study's findings. One innovative approach could involve interactive infographics or multimedia elements to engage readers and enhance comprehension of the intricate scientific details. This would elevate the article's educational value and bridge the gap between scientific complexity and public awareness.
ReplyDeleteI also find it interesting that the author chose to link the findings of the peer reviewed paper to a completely different situation involving orca whales but didn't have a source to site. This is one of my main gripes with science reporting. Scientific phenomenon are incredibly complex and cannot be related to one another as easily as by comparing one common thread, in this case, baby whales. That being said, I do think that they did a good job overall highlighting the important findings of the paper without sugarcoating or glossing over more difficult details. All in all, reporting on a study involving dolphins is certainly a smart way to capture a reader's attention.
ReplyDeleteI would agree with your rating of the article. When I was reading it, I was initially pleased with how it provides background on POPs and how bioaccumulation happens because these are topics that the everyday reader may not be familiar with. But then I found their discussion to be lacking. I find it odd that they did explain how the study discusses that bottlenose dolphins and other species have differences in blubber during lactation and would therefore have different transfer patterns. After that, it also feels like the section about orcas was kind of thrown in. I think maybe they did this as a way to emphasize the possible implications of this study and as a way of fear-mongering, but I don't think that's responsible of the author.
ReplyDeleteHi Sabrina, I really found the research article that you chose fascinating! While a portion of the methods section dedicated to statistical analysis flew over my head, the figures were very insightful and gave readers a greater understanding on POP levels in milk and serum of lactating female bottlenose dolphins and their calves--perhaps I'm wrong having not read too deeply in mammal POP studies, but this seems groundbreaking. While I also found portions of the article irresponsible in conveying the research (The orcas part clearly seen by the author as "Well I already wrote about research on them before, so let's bring that in to this article), I wanted to ask if you know of any studies done (or current efforts being made) on dolphins from the Pacific/Indian oceans? After all, the MMP facility is right on the west coast, so I think it'd be intriguing to cross-compare POP effects on the same/similar species.
ReplyDeleteI agree that this news article deserves a low rating. The study itself is interesting, but the news article doesn't seem to do a good job of portraying any relevant information in a way easily digestible by the public. The author does make a concerted effort to explain the background and interpretation in an understandable way to the public, but I feel they do this to an unnecessary level. It just ends up serving to muddle the results and makes the data even harder to interpret based on the article alone.
ReplyDelete