Stopping marine debris at the source: Effectiveness of Source Reduction Plans in Australia

Globally, single-use plastics (i.e., items only used once before being discarded plastic, such as straws, plastic bags, cigarette butts) are a substantial contributor of debris in the environment. In response, policy interventions to minimise single-use plastics and packaging have increased in the past decade (e.g., national and state level bans on plastic bags). Reduction strategies that tackle debris items at the source (i.e., Source Reduction Plans (SRPs)) have been suggested as a key strategy to achieve a reduction in debris in the environment. SRPs differ in their implementation approach, since different items require different methods depending on their characteristics, pathway, and source. In Australia, several SRPs have been applied by communities and the Tangaroa Blue Foundation (TBF). Globally, there is a lack of information available concerning the challenges associated with the implementation of SRPs, such as policy considerations and costs. Therefore, there is a need to measuring the effectiveness of specific SRPs as mitigation tools, to identify their strengths and weaknesses, and determine the best reduction approaches for specific items. We measured the effectiveness of two quantifiable SRP projects at different scales: cigarette butts (consumer level) and strapping bands used in fisheries (industrial level). There was a marginally significant decline in strapping bands in the environment over time (2004–2020), although we were unable to associate this directly to the SRP intervention (ban on ships). At a consumer level, there was a decline in the rate of cigarette butts flicked on the ground during sporting events post-SRP, with an overall reduction of 45.4% in number of cigarettes per spectator. Our results suggest the outcomes differ depending on the type of SRP, due to the different characteristics of the tackled item (i.e., source, pathway) and the respective SRP implementation mechanism. We highlight the importance of SRPs and make recommendations on future steps towards reducing single-use plastics in the environment.