Distinctly different types of plastic resin pellets have been found during our surveys of beaches adjacent to the Port of Fremantle. The newness of these pellets and the numbers found indicate one or more local sources from the port precinct and or from drainage further up the Swan River.
Survey Sites
Port Beach
Port Beach is north of the Harbour entrance and the section of beach surveyed – immediately north of Rous Head -is adjacent to the major shipping container depots and the main road into North Quay. Debris tends to accumulate in the southern corner of this section of beach as Rous Head interrupts the longshore flow especially in North West to Westerly wind regimes.
Bathers Beach
Bathers Beach is adjacent to South Mole and lies between the Roundhouse and the Fremantle Fish markets. Its location can be likened to a pocket able in the right conditions to trap and hold debris. These conditions would include river flow, and frontal activity pushing debris to the south of the harbour entry in north westerlies and then westerlies and south westerlies driving debris into the beach.
Method
Analysis of Pellets collected during autumn had shown there to be high numbers of a translucent pellet in the Port Beach sample. (1) As this suggested a local input of pellets, Bathers Beach was added into the survey sites and samples collected. These were analysed for wear, staining and concentration.
The pellets from both sites were then further differentiated into types. Where a number of pellets of the same type turned up in a sample and were distinctly new looking and or distinctly different from the background range of pellet types they were given an identification number based on appearance, shape and whether they appeared to have been extruded or mechanically cut in the manufacturing process. (2)
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