Transport, weathering and pollution of plastic from container losses at sea: Observations from a spillage of inkjet cartridges in the North Atlantic Ocean

Observations of beached polypropylene inkjet cartridges, spilled from a ship container lost in the North Atlantic Ocean, have been compiled through calls on international social media. Within a period of four years from the spillage, a total of about 1500 cartridges was reported in locations as far apart as Florida and northern Norway. The distribution of cartridges reflected the principal surface currents in the ocean, with some carried by the Azores and Canary currents around the North Atlantic Gyre, and others transported northwards with the North Atlantic and Norwegian currents. Along the shorelines of the UK and Ireland, there was a clear, preferential accumulation of cartridges on west- and south-facing coasts, consistent with the direction of the North Atlantic current and the heading of the principal winds. Dates of first sightings in various regions throughout the North Atlantic (and as reported on social media) suggested that cartridges traveled on average at around 6-13 cm s. These observations and estimates were largely consistent with simulations of the dispersion of free floating, neutrally buoyant particles from the spillage site derived from PlasticAdrift, an empirical model based on drifter tracking data. Microscopic and X-ray fluorescence analyses of selected cartridges revealed a high degree of exterior weathering, resulting in chalking and embrittlement of the polypropylene and the formation of microplastics rich in Ti, chemical fouling of interior ink foams (where still present) by Fe oxides, and, in some cases, the presence of an electronic chip containing Cu, Au and brominated compounds. Significantly, the latter characteristic renders cartridges as electrical and electronic waste and means that current, conventional regulations on plastic cargo lost at sea are not applicable here. More generally, the study highlights the potential usefulness of social media-led citizen science to marine research, and inadequacies in the relevance and robustness of instruments and conventions that deal with plastic waste in the ocean.