Study finds Great Lakes water, beer have varying levels of plastic particles

Researchers puzzled by differences in beer, water

Credit: Wikimedia Commons

DETROIT - There are plastic particles in our water and even more in some of our beer, according to a study published earlier this month in the Public Library of Science. 

While researchers explained it's no surprise plastic particles are in Great Lakes tap water, what's really puzzling is the varying levels of plastic particles found in the beer made with that same water.

It's one thing to have water polluted with man-made particles, but what's happening during brewing processes that is adding such man-made particles to the beer? There is no definitive answer to that question yet, researchers say. 

Researchers examined beer last year from 12 breweries that use municipal water drawn from the Great Lakes. Three breweries drew water from Lake Superior, four from Lake Michigan, one from Lake Huron, two from Lake Erie, and two from Lake Ontario. Seven brands of beer were purchased from Minneapolis liquor stores, two were purchased directly from breweries in Duluth, Minn., and the remaining three were purchased in Alpena, Mich. and Rochester, N.Y. 

All beers were packaged in 12- or 16-fluid-ounce aluminum cans, 12-fluid-ounce glass bottles, 64-fluid-ounce glass growlers, or 32-fluid-ounce glass howlers

The study found beer contains an average of 4.05 man-made particles, mostly plastic fibers, per liter. However, researchers found a puzzling difference between the amount of particles found in the beer and the water with which it was brewed. In some instances the beer contained much more particles than the water with which it was brewed. Other beers contained less particles than the water (see the table below). 

That means if you're drinking beer and tap water daily you could be ingesting about 5,800 plastic particles each year. 

"While both the municipal tap water and the beers analyzed all contained anthropogenic particles, there seemed to be no correlation between the two, which would seem to indicate that any contamination within the beer is not just from the water used to brew the beer itself," reads an excerpt from the researchers' report. 

This table shows how many particles were found in the water and beer from the seven municipalities where the Great Lakes water was drawn: 

But what about Germany, where beer is supposed to be "purist?" Researchers found that German beer on average had 22.6 particles per liter and a wider range of particles per liter than what is shown in the above table. 

From the study: 

While the tap water study represents the first of its kind, our beer study was intentionally aligned with that of Liebezeit et al. (2014) [32] but focused on Laurentian Great Lakes (USA) beers as opposed to beers from Germany. While this prior study reported 2 to 79 fibers/L of beer with an overall mean of 22.6 particles/L, our study had a narrower range, 0 to 14.3 particles/L, and a lower overall mean (4.05 particles/L). The most significant divergence between our studies, however, is that little other than fibers were found in the Great Lakes beers. The German beers, on the other hand, had 12 to 109 fragments/L and 2 to 66 granules/L in addition to the fibers. These differences may be attributable to varying brewing customs and regulations in Germany as compared to the US. In fact, a significant amount of variation in processing exists within the U.S. alone. In order to increase shelf life, national brands tend to filter their beers more thoroughly, while locally distributed craft beers may modify or forgo this step completely because they feel it affects the overall experience.

Here is more from the study explaining how even more particles were found in beer brewed in Colorado: 

Even though the average number of particles found in beer (4.05 particles/L) was similar to the average number of particles found in tap water (5.45 particles/L), not even a weak correlation could be drawn when comparing the results from specific beer brands to their corresponding municipal tap water supply. In fact, the highest and lowest counts in this study came from two beers that were brewed in the same city using the same municipal water supply. This indicates that product processing may be integral to understanding anthropogenic contamination. The brand with the highest count has breweries in several states. Interestingly, the first beer samples processed in January were a different style of beer from the same company, but they were brewed in Colorado. The data for that beer were not included in our study because it did not fulfill the requirement of having its water drawn from the Great Lakes, but the mean for that beer (15.7 particles/L) was also very high. Future research efforts could focus on a particular facility, sampling at multiple locations throughout the process, in an effort to identify the source of contaminants.

It should be noted that most of the beers selected for this study were pilsners. This was intentional as wheat beers and stouts tended to clog the filters and considerably lengthen the filtration times. If there is a significant difference in the brewing process for various styles of beer, it may affect the outcome of the results and future research efforts could focus on understanding any potential differences in contamination among varieties.

In reviewing the results, it is clear that the pore size of the filter did not play a role in either the density or the size of particles detected (> 100 μm) found in the samples. Although the average length of the particle found in tap water was the smallest (0.96 mm) it was only larger by two hundredths of a millimeter when compared to the average length of particle found in beer (0.98 mm) and approximately one tenth of a millimeter when compared to the average length of particle found in salt (1.09 mm).

In order to give an indication of how many anthropogenic particles a person might consume in a year, we conducted a similar exposure analysis with beer, using averages, as we did with water. According to the average number of particles found in the 12 brands tested in this investigation, an individual consuming a single 12-fluid-ounce beer once a day could be ingesting nearly 520 particles annually. Since a slight range was found between brands, this annual ingestion could be negligible or as high as 1,800 particles.

The researchers concluded: 

This investigation reveals troubling amounts of anthropogenic debris in global tap water, North American beer, and internationally sourced (but US purchased) sea salt. Particles were found in 81% of tap water samples, as well as in all 12 brands of beer and sea salt. These findings add to a growing body of knowledge about plastic pollution in human consumables. ...

... The high proportion from drinking water is of particular concern because it is difficult to recommend practical strategies for avoiding ingestion. While sea salt can be reduced and beer can be avoided, drinking water is not something that can or should be eliminated or restricted, yet tap water is the most prominent source of anthropogenic debris among the three consumables analyzed in this study.

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