Data on the type, provenance, quantity (density), and rate of accumulation of beach-washed plastic debris were recorded on Henderson Island, a remote, uninhabited island in the South Pacific during 29 May – 15 August 2015. Henderson Island is rarely visited by humans, thus debris on the islands' beaches may act as a proxy for the adjacent South Pacific Ocean. The island was found to contain the highest density of debris anywhere in the world, up to 671.6 items/m2 (mean ± SD: 239.4 ± 347.3 items/m2 on the surface of the beaches. Approximately 68% of debris (up to 4,496.9 pieces/m2) was buried <10 cm in the beach sediment. Up to 26.8 new items/m are thought to accumulate daily.
Maintenance and Update Frequency: notPlanned
Statement: Methods are detailed in Lavers & Bond (2017): https://www.pnas.org/content/114/23/6052.abstract
In brief, micro- (2–5 mm) and macrodebris (≥5 mm) items, including plastic, glass, wood, and metal items, were sampled along the North (2.1 km long) and East (1.9 km long) Beaches of Henderson Island from 2015 May 29–August 15. We sampled surface beach debris along five 30-m transects and 10 20-m transects in the beach-back. Buried debris (0–10 cm) was sieved from all sediment excavated in 10 0.4 × 0.4 m quadrats. Plastic accumulation was sampled along a 10 × 0.2 m transect centered on the high tide line on North Beach for six consecutive days. To extrapolate the total amount of debris on Henderson Island, we multiplied the mean surface densities and mean buried densities by total beach area and added the debris from a highly polluted area separately (SI Materials and Methods). All debris items (≥2 mm on beaches and ≥5 mm in the beach-back) encountered on sample transects or quadrats were counted, weighed, and sorted by type and color.
Royal Society for the Protection of Birds
David and Lucile Packard Foundation
Farallon Islands Foundation
Government of the Pitcairn Islands