Accumulation and fragmentation of plastic debris in global environments

Abstract

One of the most ubiquitous and long-lasting recent changes to the surface of our planet is the accumulation and fragmentation of plastics. Within just a few decades since mass production of plastic products commenced in the 1950s, plastic debris has accumulated in terrestrial environments, in the open ocean, on shorelines of even the most remote islands and in the deep sea. Annual clean-up operations, costing millions of pounds sterling, are now organized in many countries and on every continent. Here we document global plastics production and the accumulation of plastic waste. While plastics typically constitute approximately 10 per cent of discarded waste, they represent a much greater proportion of the debris accumulating on shorelines.Mega-and macro-plastics have accumulated in the highest densities in the Northern Hemisphere, adjacent to urban centres, in enclosed seas and at water convergences (fronts). We report lower densities on remote island shores, on the continental shelf seabed and the lowest densities (but still a documented presence) in the deep sea and Southern Ocean. The longevity of plastic is estimated to be hundreds to thousands of years, but is likely to be far longer in deep sea and non-surface polar environments. Plastic debris poses considerable threat by choking and starving wildlife, distributing non-native and potentially harmful organisms, absorbing toxic chemicals and degrading to micro-plastics that may subsequently be ingested. Well-established annual surveys on coasts and at sea have shown that trends in mega-and macro-plastic accumulation rates are no longer uniformly increasing: rather stable, increasing and decreasing trends have all been reported. The average size of plastic particles in the environment seems to be decreasing, and the abundance and global distribution of micro-plastic fragments have increased over the last few decades. However, the environmental consequences of such microscopic debris are still poorly understood.

Neustonic microplastic and zooplankton in the North Western Mediterranean Sea

“…Recently, the issue of microplastics (fragments less than 5 mm) has attracted increasing attention worldwide. This ubiquitous, persistent debris requires centuries to completely degrade (Derraik, 2002;Hansen, 1990;Goldberg, 1997;Arthur et al, 2009;Barnes et al, 2009;Zarlf et al, 2011).…”

Global Distribution, Composition and Abundance of Marine Litter

“…Nevertheless, common patterns indicate the prevalence of plastics, greater loads close to urban areas and touristic regions (Barnes et al 2009). Data expressed as items m −2 or larger areas are more convenient for comparisons.…”

“…Packaging, fishing nets and pieces thereof, as well as small pieces of unidentifiable plastic or polystyrene account for the majority of the litter items recorded in this category (Galgani et al 2013). Some of this can take hundreds of years to break down or may never truly degrade (Barnes et al 2009). …”

“…Initially described in the marine environment in the 1960s, marine litter is nowadays commonly observed across all oceans (Ryan 2015). Together with its breakdown products, meso-particles (5-2.5 cm) and micro-particles (<5 mm), they have become more numerous and floating litter items can be transported over long distances by prevailing winds and currents (Barnes et al 2009). …”

Micro-and macro-plastics in marine species from Nordic waters

“…number of items per area or total weight per area. Some common patterns have emerged though, such as greater loads of debris close to urban and touristic areas (Barnes et al, 2009). Flooding and heavy weather events also increase the number of beached items found, this is due to either the increased transport of plastics from terrestrial sources or the deposition of plastics items following high tides and storms.…”