Common Plastics in Environment Absorb Contaminants

A California study shows that the most commonly produced plastics that are littered in the environment are also the ones that absorb the most chemicals, a finding that poses a greater risk for marine animals and those that eat them.plastic

The absorption ability of these plastics continued for longer periods of time than previously thought. Chelsea Rochman, a doctoral student at University of California, Davis’ School of Veterinary Medicine, conducted the study for 12 months at five locations in San Diego Bay, the school reports. The study, whose results are published in the journal, Environmental Science & Technology, is the first controlled, long-term field experiment measuring the absorption of contaminants by the five most common plastics.

Those plastics are: 1) polyethylene terephthalate (PET), commonly used in water bottles; 2) high-density polyethylene (HDPE), used in detergent bottles; 3) polyvinyl chloride (PVC), commonly used in clear food packaging; 4) low-density polyethylene (LDPE), found in plastic shopping bags; and 5) polypropylene (PP), commonly used in yogurt containers and bottle caps.

The university explains how Rochman did her research:

Rochman and her colleagues deployed pellets of each plastic type in mesh bags tied to a dock at each study site. They retrieved them periodically to measure the plastics’ absorption of persistent organic pollutants.

“Consistently in our study, we found polyethylene [HDPE and LDPE] and polypropylene [PP] absorbed much greater concentrations of contaminants than PET or PVC, and those are the most commonly mass produced and consumed plastics,” says Rochman. “They are also the most commonly recovered as marine debris.”

The plastics with the highest absorption rates are also the most common. For example, HDPE, LDPE, and PP accounted for 62% of all plastics produced around the world in 2007, Rochman’s study found. PVC and PET made up 19% and 7%, respectfully, in the world. It was noted that while PVC did not take up proportionately as many pollutants as the other plastics, vinyl chloride is considered a carcinogen and toxic.

The researchers also were surprised at how long the plastics absorbed contaminates while in the environment, reports Mother Jones. They expected the plastics to absorb pollutants for several months. Instead, they were surprised to find that it would take 44 months for HDPE to stop absorbing pollutants.

“It surprised us that even after a year, some plastics would continue to take up contaminants,” Rochman says. “As the plastic continues to degrade, it’s potentially getting more and more hazardous to organisms as they absorb more and more contaminants.”

Source: “Plastics and chemicals they absorb pose double threat to marine life,” UC Davis News & Information, 1/28/13
Source: “Plastics Suck Up Other Toxins: Double Whammy for Marine Life, Gross for Seafood,” Mother Jones, 1/18/13
Image by Nigel Mykura.

7 Comments




  1. Plastics absorb toxic chemicals. Do they then release these chemicals when ingested? What is the data on that?

    Reply

      1. Dr. Bogomolova, thank you for your reply. If you don’t mind a follow-up, I would appreciate it. The subject paper indicated that plastics absorbed toxic chemicals when placed in sea water. It went on to speculate that these toxins would then poison fauna when ingested. I’ wondering if there are any studies indicating that these plastics would release these toxins when passing through the digestive tract. If they don’t, it seems to me that plastics then would provide a beneficial service by cleaning the environment of these toxins and trapping them. A link to any papers on this would be most appreciated. Thank you.

        Reply

      2. Dr. Bogomolova and E.J.,

        There is evidence that absorbed toxicants can leach out of the plastics and into organisms:
        Besseling, E., et al., 2013. Effects of Microplastic on Fitness and PCB Bioaccumulation by the Lugworm Arenicola marina (L.). Environmental Science & Technology. 47, 593-600.
        Mato, Y., et al., 2001. Plastic resin pellets as a transport medium for toxic chemicals in the marine environment. Environmental Science & Technology. 35, 318-324.

        Reply

        1. It is annoying that my “credentials” don’t authorize me for a full text view. One would think that a .gov site wouldn’t require such a thing. Anyway, what I did see is that the plastic pellets absorbed the toxins to the same concentration as in the environment. So, is the level of toxins in the lugworms(?) due to ingestion of the pellets or due to the ubiquitous presence of the toxins in the environment? One would have to eliminate the toxins in the environment to verify that the pellets are the transport mechanism. Also, the effect of the toxins doesn’t seem to be substantial anyway.

          Reply

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