Document ID: chunk:federal_register_of_legislation:F2018L01047:reg:5:p1
Version: federal_register_of_legislation:F2018L01047
Segment Type: reg
Provision Reference: reg 5 (pt 1/2)
Character Range: 9878–12942

5

Why is plastic debris a problem in the marine environment?

         Anthropogenic debris entering and accumulating in the world's oceans is comprised of many types of materials. However, a recent systematic review of the demonstrated ecological impacts of these materials (Rochman et al., 2016), found that the majority (82 per cent) were plastic. The review suggested that there is sufficient evidence now for decision makers to begin to mitigate problematic plastic debris to avoid risk of irreversible ecological harm. Other researchers (e.g. Browne et al., 2015) suggest that policies on anthropogenic debris should focus on replacing problematic products with safer alternatives by tasking ecologists and engineers to identify and remove features of products that might cause ecological impacts.
         Plastics are an obvious, problematic target for action. Experts say fishing gear (ropes and nets made from synthetic fibres), balloons and plastic bags are the biggest entanglement threat to marine fauna, and plastic bags and utensils are the biggest ingestion risk for seabirds, turtles and marine mammals (Wilcox et al., 2016). Plastics may also be chemically harmful in some contexts, either because of their potential toxicity or because they absorb other pollutants (Rochman et al., 2013).
         As plastic debris accumulates in the environment, exposure to physical, chemical and biological processes results in its fragmentation into smaller pieces, and the potential for ingestion by animals increases (Browne et al., 2008). Potential routes for entry of microplastics (including beads and fibres) into the environment include fragmentation of larger items, introduction of small particles that are used as abrasives in cleaning products, and spills of plastic powders and pellets in sewage waste.

         Fragments of plastic on the shoreline. Image: © CSIRO

         Seabirds often eat floating plastic. Wilcox et al. (2015b) suggested that nearly all species of seabirds will eventually be found ingesting plastic, based on the discoveries reported so far. For example, 21 per cent of surveyed wedge-tailed shearwater (Ardenna pacifica) chicks on Heron Island in the southern Great Barrier Reef were fed plastic fragments by their parents, ingesting 3.2 fragments on average (Verlis et al., 2013). In addition, plastic-derived polybrominated diphenyl ethers (a very common class of flame retardants) are found in the abdominal fat tissues of short-tailed shearwaters (Ardenna tenuirostris) in the north Pacific Ocean, presumably transferred from ingested plastics (Tanaka et al., 2013).
         6  /  Threat Abatement Plan

           An extreme example of plastic ingestion — an albatross chick from Midway Island, USA, killed by the plastic it was fed by parent birds. Image: © Britta Denise Hardesty

           Studies published between 1985 and 2012 identified general plastic as the main debris ingested by marine turtles, followed by soft plastic, rope and styrofoam (Schuyler et al. 2014). Up to 52 per cent of sea