| Summary: | With the help of the local people we met during the course of the 2015 Odyssey, the main objective, obtaining a collection of comparable data about marine plastic pollution using the NOAA internationally recognized protocol, has been achieved. It cannot be sufficiently stressed that not one of the 30 sampled shorelines during this worldwide journey was free from marine plastic debris. As for the recent identification of plastic debris in the Arctic and Antarctic areas, this observation confirms that plastic contamination in the oceans is ubiquitous. Whether in terms of macrodebris (>2.5 cm) or microplastics (< 5 mm) concentrations, Hawaii constitutes by far the 2015 Odyssey’s most notable hotspot. The highest macrodebris concentration registered at Kamilo Point in Hawaii (more than 3,500 macrodebris per 100 m2) was almost ten times greater than the second hotspot of the 2015 Odyssey, Pago Bay (372) on Guam Island in the Mariana Archipelago. Hawaii also constitutes the highest microplastics concentration hotspot with more than 94,000 particles per m2 collected once again at Kamilo Point again. For comparison, the second highest concentration, Ovahe beach on Easter Island, revealed more than 24,000 microparticles per m2. Unfortunately, based on their locations, marine macrodebris concentrations can suffer bias due to direct waste disposal (intentional or accidental) of tourists and/or local residents, and also because of the consecutive shoreline clean-up campaigns. Therefore, microplastic concentrations are a more reliable indicator to establish a comparison between study sites. On that basis, Northeast Pacific islands – especially the Hawaiian Archipelago – experience the most significant marine debris accumulation, followed by those of the South Pacific, Northeast Atlantic, Indian, Northwest Atlantic, Northeast Pacific and South Atlantic Oceans respectively. The macrodebris and microplastic average concentrations are summarized below in Figure 1. In qualitative terms, the hard plastic fragments category ...
|
|---|