No abstract

Plastic pollution is threatening aquatic ecosystems and wildlife. Understanding the characteristics and extent of plastic pollution is the first step towards improving management and therefore the environmental impacts. Pre-production pellets are used in the manufacture of a range of consumer items. The Avon–Heathcote Estuary/Ihutai in Aotearoa–New Zealand, an important wildlife habitat, was assessed for the presence and characteristics of pre-production pellets. Following a visual survey of the estuary’s perimeter to establish overall levels, seven accumulation hotspots were identified, and surveyed in more detail. The enumeration and characterisation of pellet colour, size, morphology, degree of weathering and polymer type was undertaken. A total of 3819 pellets were identified, with pellets present at all sites. The pellets were predominantly clear (86%), 3 mm in size (54%), cylindrical in shape (62%), showed moderate weathering (41%) and were made of low-density polyethylene (LDPE) (53%). Pellet abundance and characteristics varied between sites. Accumulation and abundance may be influenced by river inflows along which plastic manufacturers are located, weather conditions, locality to stormwater outlets and pellet characteristics. Pellet pollution is a notable problem in the Avon–Heathcote Estuary/Ihutai and it highlights the need to better understand the sources and improve best management practices.

No abstract

Plastics are an emerging class of environmental contaminants whose impacts are not yet fully understood. Trace elements, another class of environmental contaminant and commonly associated with plastics, have been widely researched and are known to be toxic to organisms. However, the combined impacts of these two contaminants on the environment remain unclear. Here, we reviewed the current knowledge of the types and concentrations of trace elements associated with plastics, the role of plastics in creating new exposure routes, the processes involved in the release of trace elements from plastics, and the transport of plastics through environmental compartments. Trace elements inherent in plastics, due to addition during manufacture for formation or functional properties, are typically present at higher concentrations than those that are acquired from the environment, and consequently are likely to have greater impacts. Trace elements are continuously released into environmental matrices from plastics but may be released at higher concentrations when exposed to rapid changes in environmental conditions (pH, ionic strength, redox potential, salinity, UV levels). Plastics potentially provide additional exposure routes for organisms to trace elements. For example, exposure to trace elements may occur when organisms ingest plastics, use them for shelter and nest building or as a surface to attach onto. Further research to improve our understanding of this complex contaminant should focus on environmentally relevant studies on trace element release and their effects.