Microplastics Contaminated by Pollutants in Ocean Waters Can Affect Food Chain

Plastics pollute the oceans in the form of big sheets of wrappings from sea vessels all the way down to six-pack rings. British researchers have now found that microscopic bits of the deteriorated pollutants pass toxic contamination on to the lowest levels of the marine food chain, as will be reported in November in American Chemistry Society's Environmental Science and Technology journal, according to a new press release.

Until now, not much attention was paid to these microplastics because attention was being paid to the severe problems caused by the intact plastics. Plastic pollutants deteriorate over time in the salinated ocean waters and this deteriorated debris breaks down into microscopic particles of plastic. These microscopic particles, or microplastics, litter the ocean and its various marine environments. Microplastic's also enter the marine environments through waste waters that carry household and industrial cleaning products. Microplastics are included in the manufacture of cleaning products added as "scrubbers" that get washed out with waste water and enter the marine system.

Microplastics can absorb high levels of the toxic chemical polychlorinated biphenyl (PCB); it is PCBs that are also found in carpets, which led the U. K. Health Ministry to warn parents to keep their babies off of carpets. PCBs are chemicals formed by adding chlorine to biphenyl. PCBs are on the Agency for Toxic Substances and Disease Registry (ATSDR).

It was not previously known that microplastics attract, hold and transport toxic water pollutants. British researcher Emma L. Teuten and her colleagues conducted studies to determine the threat to marine animals posed by these toxin transporting microplastics.

In their study Teuten and her team exposed microplastics to the chemical phenanthrene, which is the colorless crystalline hydrocarbon C14H10. Phenanthrene (PAH) is a major marine pollutant that is on the EPA Priority Pollutant list and a toxic pollutant so designated by the Clean Water Act. PHAs are associated with the risk of chronic diseases.

The researchers then added a few millionths of a gram of the PAH contaminated microplastics to the sediment in which sediment-dwelling marine worms, called lugworms, were burrowed. Lugworms are segmented marine worms that burrow in sandy shores. Teuten's team found that even the introduction of a few millionths of a gram of PAH contaminated microplastic showed up in the tissue of the worms: the lugworm's phenanthrene accumulation increased 80 percent.

This PAH accumulation is of particular importance because the lugworms are at the bottom of the marine food chain. PAH molecules accumulated in the worm's tissues would be transfered to the next level of the food chain. Additionally, the molecules would be biomagnified: the toxins would undergo biological magnification and the concentration of the PAH would increase in each level of the food chain with the potential of ending ultimately in the human food chain.

Teuten's study suggests that the transportation of toxic pollutants throughout the ocean waters and in marine organisms is catalyzed by the introduction of toxins that are being held by the microplastics into the lowest level of the marine food chain. Microplastics are now shown to pose a threat to marine environments on a global scale and to the human food chain as well.

""Microplastics" may pose previously unrecognized pollution threat," Eureka Alert/American Chemical Society.