by Hamed Saber
Estrogenic Toxin Found in Widely Used Plastic:
[Via All Today's News - Sightline Daily]
Researchers in Germany have found traces of an unknown estrogen-mimicking chemical leaching into mineral water from a widely used type of plastic bottle.
The bottles are made from polyethylene terephthalate, or PET, and the scientists detected estrogenic activity in 78 per cent of samples, according to a study published online in Environmental Science and Pollution Research.
[More]
I love the world today. Just a few years ago, we would all have had to stick with a newspaper account of this research. These often do not provide the nuances present in a paper and sometimes are factually wrong. So I have learned to seek other sources on something like this.
Thankfully, the article is Open Access and is available for anyone to read. One thing to be aware of. this report examines mineral water from natural springs, not the filtered tap water we in find most of the bottled water in the US. This could add some interesting complications.
Right off I saw something in the abstract that was different than the article. The former says that activity was seen in 60% of the samples, not 78% as the newspaper article said.
So, reading the article cleared this up. 78% of all the plastic bottle samples showed estrogen-like activities. But, 33% of all the glass bottle samples also showed the same activity. In fact, one of the glass samples matched a plastic sample for the highest estrogen-like activity – about 75 ng/L. This was a cell-based assay looking at anything in the water that bound a human estrogen receptor.
There is something more interesting here than the newspapers suggested. Glass is the most inert substance we have for packaging a liquid, yet 33% of these packages had water with estrogen producing activities. The large number of plastic bottle samples is unexpected but that anything was found in samples from glass bottle is really perplexing
The report gets even more complex. In one case, they examined spring water from the same source packaged in glass or in plastic. This source had high levels of estrogen activity no matter what the packaging. In fact it had one of the highest levels of activity of any of the samples, indicating that the water and not the packaging material was the problem.
Here is what they have to say:
In contrast to estrogens naturally occurring in foodstuff and beverages, the sources of estrogens in water must be exogenous.
It sure appears that in this case, the water itself is responsible and not the packaging. They explain possible reasons for this in the discussion.
Next they used an organism-based assay – the effects of the waters on a snail. This gets even more interesting, since this system is not really estrogen receptor specific but can respond to a wide range of compounds.
So, what happened when they examined the waters from that spring that seemed to have some activity no matter how it was packaged ? In this assay, the water from the glass packaging showed no activity while the water packaged in plastic showed high levels of activity. Confusing? Well, it has to do with the type of research that is being reported.
This is really just an exploratory research project. It is simply to report a very interesting observation, presenting some reasons for the results and suggesting a range of further experiments to nail down what is going on. It is in no way a final report with definite conclusions, no matter how much the news reports wants to make it seem that definitive answers are present.
Remember, most science hypotheses are conditional, with conclusions always having a chance to be altered. The more examination that occurs into these results, the firmer the reasons behind everything becomes and the more likely a particular hypothesis suggested becomes.
Newspaper accounts almost never get this right, discussing preliminary conclusions as if they were well-founded. No wonder so many people get frustrated when reading about scientific results in the media.
These research are reporting results from the begining of a research project. They wanted to examine and quatify ways to assay for estrogen-like activities. They chose water since it should have no intrinsic biological properties to confuse the assays. What they found was much more interesting, and scary, than the news article reported. Here are the conclusions from the paper:
Our findings provide first evidence for a broad contamination of mineral water with xenoestrogens, typically in the range of 2–40 ng/l EEQ with maximum values of 75 ng/l EEQ. Consumption of commercially bottled mineral water may therefore contribute to the overall exposure of humans with endocrine disruptors. Moreover, it is probable that this estrogenic contamination originates from plastic food packaging materials because mineral water bottled in PET and Tetra Pak is more estrogenic than water bottled in glass. This gives rise to the assumption that additives such as plasticizers or catalysts migrate from the plastic packaging into the foodstuff. Though yet unidentified, these substances act as functionally active estrogens in vitro on the human estrogen receptor alpha and in vivo in a molluskan model. Therefore, we may have identified just the tip of the iceberg in that plastic packaging may be a major source for xenohormone contamination of many other edibles. Still, this study was not designed to evaluate whether the consumption of plastic packed nourishments comprehends the risk of endocrine disruptive effects in humans. It instead provides an insight into the potential exposure to EDCs due to unexpected sources of contamination.
EDC stands for Estrogen Disruptive Chemical and EEQ stands for estradiol equivalent. What they show for the first time is that commercially packaged spring water may have compounds in it that disrupt estrogen pathways in humans. They remark that their initial investigations revealed surprisingly high levels of such disrupters .
These researchers looked at EDC in a location no one expected to find any and, they found some. This is the real take home message. At this point we only know that there is something in some of the spring waters that mimics estrogen. We don not know what it is, if it is the same thing from the different waters and whether it really will have any biological effects in humans.
While the study was not designed to really examine what this means for human consumption (something lost in the newspaper account), it does suggest further research has be done. Again, no one ever really looked in bottled spring water because no one expected there to be anything there.
The researchers identify three places were the EDCs can be coming from. One is the packaging itself. This is what the newspaper accounts mention. But the activity could come from something that would have no such effect in humans.
Antimony can be found at much higher levels in water from plastic bottles and it has been shown to mimic estrogen in some assays but not actually in human beings. Further work will have to be done to tease out whether any of the activity seen has any effect in humans.
The second place where EDCs could be introduced is in the packaging process, such as from detergents or disinfectants used to clean the pipes of the facility. They found some evidence for this. Again, the researchers will need to find out just what is causing the activity.
The third possibility is that the water itself is contaminated, since some of the spring water appeared to have EDCs no matter how it was packaged. As the authors state:
Another source of hormonal activity in groundwater may be the reflux of synthetic estrogens like 17α-ethinylestradiol and other pharmaceuticals from wastewater discharge.
To me, this is actually a scarier possibility than the contamination from plastics. This would be a problem no matter how the water was packaged, whether in plastic or glass. This would explain why some water sources have activity while others, packaged the same way, show no activity. It would also imply actual compounds that are biologically active in humans are present.
So we have a preliminary paper that identifies surprisingly high amounts of estrogen-like activity in bottled mineral water. They identify three possible reasons for this and discuss examples they have for each. The fact that they found even one example is a little disconcerting. The fact that they found examples of all three possibilities raises some very intriguing and possibly scary questions.
The news reports only discuss one of the three, the one that fits a current meme (plastic is unnatural and bad for us all). While possibly true, it is not really anything that can be concluded by the paper. Even the authors state this.
Secondly, the reason that is actually the most unsettling to me is that the activity could come from groundwater contamination. This would be most likely to be from compounds that are directly EDCs because they are mimics of human estrogen, not just compounds that fortuitously have the activity but that our bodies will never react to in a biological way.
This why it is important to be able to read the actual paper. You can start with the abstract, skim the conclusions and then dig deeper into the results and methods. Very often the authors state their important conclusions and facts in very simple language that most can understand (or with a little dictionary help if words like exogenous are not immediately decipherable).
The take home message is that the newspaper reports actually only discuss one part of the paper, leaving out some of the interesting nuances that actually implicate other aspects of the research that are more disconcerting than what the papers discussed. Pharmaceuticals in the groundwater may be much more important questions to examine than packaging. The former are known human EDC while the latter is still speculative.
So, what have I personally learned from the report? It is hard to know right now how important packaging is versus the source, at least when it comes to mineral water. But I will keep my eyes open for some more information
I can stay away from spring water. It is not pure water and can have many things present in it anyway. I can try to only drink packaged water that is vapor distilled, deionized or purified by reverse-osmosis. Nothing should survive any of those processes but H2O. It is what scientists use because they have to be sure that when they use water for an experiment, that is all it has in it.
But what to drink the water out of? It may well be that filtered tap water will work fine but carrying it around in a glass bottle presents problems, as may plastic (aside from the other problems plastic may present, such a energy for production and environmental waste). A reusable canteen made of metal may be best but again may not be very convenient. At the moment, there is not an easy choice. So I will be wary and wait for more information.
I just wish the media reports had been more useful. I now feel I have better information to make a rational choice between different alternatives, rather than just running away from one.
As an aside, this paper is intriguing as a scientist because I am willing to bet that the basis of this paper was an accident. I would be surprised if someone out of the blue said “Let’s look at mineral water.” There would have been little empirical evidence that they would find anything positive. Researchers often do not do experiments where a negative answer is expected. It is hard to get this sort of work published. Scientists seldom work on anything without the thought of being able to get something publishable from the work.
Just speculating but I would imagine that they were developing assays in the lab, using water as a negative control. They would use these to look at a wide range of EDC. One of the post-docs or graduate students, drinking a bottle of Perrier (or similar, as a quick look via Google indicates that the Germans drink the most mineral water per capita in the EU and most of it is supplied from France ), decided to see what happened when they used that rather than the normal water control. Imagine the surprise when it read out positive!
Talk about a fun, easy piece of work. Find something surprising and unexpected that could have huge health implications. They will be writing about this work for a long time.
