Spatial and temporal variations in debris accumulation and composition on an estuarine shoreline, Cliffwood Beach, New Jersey, USA

A twelve month field investigation documents differences in cross shore accumulation and composition of debris on the dune, backbeach, and foreshore of a sandy estuarine shoreline. Debris was gathered monthly within 3 belt transects extending from the dune crest to the low tide terrace (base of the foreshore). Individual pieces of debris were classified by type, function, degree of fragmentation, length, weight, and location on the beach profile (dune, vegetated backbeach, backbeach and foreshore). Plastic comprised 42.5% and glass 29.3% of the 5793 pieces of debris that were collected. Debris was primarily consumer and household related items, and the greatest quantities of debris were found during beach user months. The cross shore spatial distribution of debris reflects the influence of wind or wave processes across the profile with small lightweight debris on the wind-dominated upper profile and heavier debris on the wave-dominated lower profile. A chi-square test revealed that more plastic was observed than expected in the dune and backbeach areas with the greatest quantities found after onshore winds. More glass was observed than expected on the foreshore where low wave energies prevent transport higher on the beach profile.