http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0085433

Rochman CM, Hentschel BT, Teh SJ (2014) Long-Term Sorption of Metals Is 
Similar among Plastic Types: Implications for Plastic Debris in Aquatic 
Environments. PLoS ONE 9(1): e85433. doi:10.1371/journal.pone.0085433

Abstract
Concerns regarding plastic debris and its ability to accumulate large 
concentrations of priority pollutants in the aquatic environment led us 
to quantify relationships between different types of mass-produced 
plastic and metals in seawater. At three locations in San Diego Bay, we 
measured the accumulation of nine targeted metals (aluminum, chromium, 
manganese, iron, cobalt, nickel, zinc, cadmium and lead) sampling at 1, 
3, 6, 9 and 12 months, to five plastic types: polyethylene terephthalate 
(PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), 
low-density polyethylene (LDPE), and polypropylene (PP). Accumulation 
patterns were not consistent over space and time, and in general all 
types of plastic tended to accumulate similar concentrations of metals. 
When we did observe significant differences among concentrations of 
metals at a single sampling period or location in San Diego Bay, we 
found that HDPE typically accumulated lesser concentrations of metals 
than the other four polymers. Furthermore, over the 12-month study 
period, concentrations of all metals increased over time, and chromium, 
manganese, cobalt, nickel, zinc and lead did not reach saturation on at 
least one plastic type during the entire 12-month exposure. This 
suggests that plastic debris may accumulate greater concentrations of 
metals the longer it remains at sea. Overall, our work shows that a 
complex mixture of metals, including those listed as priority pollutants 
by the US EPA (Cd, Ni, Zn and Pb), can be found on plastic debris 
composed of various plastic types.

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