Pollution and Debris

The issue: Chemical pollution, toxic and solid residues and debris, including plastic, result from anthropogenic activities and the ocean is often the ultimate sink. There are numerous realised and potentially harmful effects of these pollutants, which vary depending on use and material. Major types of pollution include garbage, liquid chemicals, solid residues that make their way into the ocean through varied pathways including  open dumping, spills, waste releases, natural disasters, hydroclimatological extreme events, shipping, industrial activities and from degrading debris (e.g. leaching from plastic or decomposing organic material). These direct and indirect coastal, riverine and atmospheric inputs vary from one region to another and are often greatest near the inflows (see Chapter 20, OMA). For example, nitrogen load from human activity into water ways was estimated at 32.6 MMT/yr (Mekonnen and Hoekstra 2015), and between 5 and 13 million tonnes of plastics (Jambeck et al 2015). Also, between 1990 and 1999 an estimated 6.8-5000 thousand tonnes of oil entered the ocean as run off alone (National Research Committee 2003). Assessing the impacts of these anthropogenic inputs (especially nutrient, sewage inputs from diffuse sources) and their combined effect is complicated (Jambeck et al 2020) and although impacts are evident in the deep sea few qualitative and accumulative studies are available (Ramirez-Llodra et al 2011).

The Working Group: The DOSI Pollution and Debris working group aims to 1) improve public understanding of and promote research into the patterns, impacts and relative risk of pollution and debris in the deep sea, 2) advocate for the consideration of deep-sea science in policy development and conservation initiatives, augmenting work already being done in shallow waters, 3) provide expert opinion on pollution and debris concerns through written responses, workshops, and engagement with pollution and debris-focused groups.

Current Activities: We are working to support the International Negotiating Committee (INC) on Plastic Pollution. For the Committee’s second meeting, held in 2023, we prepared  a policy brief on the deep-ocean impacts of plastic pollution in both English and Spanish. You can read our Participation Report from the meeting here.

We plan to write further policy briefs on the following themes:

• Improved practice in fisheries to reduce fisheries-based marine litter
• Improved practice in merchant shipping sector to reduce shipping-based marine litter
• Why the knowledge on deep-sea contaminants is crucial in baseline environmental impact studies
• Developing a list of existing groups working on marine plastic pollution with which to engage, with the aim of adding the deep-sea perspective.
• Press pack, providing a unified expert opinion on the impacts of pollution and debris
• Development of a reference listing of benthic and pelagic studies about plastic/debris/pollution in the deep sea
• Discussion of the differing methods of assessing plastic in the marine environment, with the aim of developing best practices for the global community.
• Developing a matrix to help inform communities of relative risk of different deep sea threats, along with other WGs