A study of beach litter during lockdown, which included Muizenberg Beach, has found that much of it is locally produced plastics.
Plastics – including foamed plastics and cigarette butts (their filters are made from a plastic called cellulose acetate) – accounted for 92% to 99% of litter items by number, and 85% to 94% by mass.
Glass was most prevalent at Surfer’s Corner in Muizenberg.
The study found lockdown did not markedly diminish pollutants on the beaches because there was enough residual land litter to wash through the storm drains.
The City’s environmental department, national government’s Working for Coast Programme and Professor Peter Ryan’s research team at UCT produced the study, which looked at 250m of beach at Milnerton in Table Bay and at two 400m stretches of beach on the northern False Bay coast, one at Muizenberg and one east of Sunrise Beach.
The study’s daily monitoring of street litter in Muizenberg showed that the amount of litter doubled as we moved from level 5 to level 4 lockdown.
The two teams were issued with permits to legally work along the three meticulously cleaned sections for the last 10 days of the level 5 lockdown and then throughout lockdown level 4.
Professor Ryan said the study showed that compared to data from previous studies of daily accumulation at Milnerton and Muizenberg, litter loads were not much lower during lockdown, because most litter washes ashore rather than being left by beach-goers.
“Despite the lower litter levels on land, there appears to have been enough residual litter trapped in storm drains to keep litter levels at ‘normal’ levels at least through the end of April. Further studies will assess how much the return of beach-goers affects litter loads, particularly at intensely used beaches such as Muizenberg’s Surfer’s Corner,” he said.
Each item of litter – collected daily – was washed, dried, and categorised according to its type of material and what it is used for. Items were counted and weighed. The oldest item that the team found was a soft drink lid manufactured in 1993.
Some 94% of identifiable litter came from local sources, but only 8% of the local rubbish had goose barnacles and bryozoans. This, the study suggests, shows that local rubbish had not been in the water as long as items collected from Indonesia.
Some 81% of bottle lids and bottles from Indonesia had these, which showed they had been in the ocean a long time. The study identified the country of manufacture for 1 400 items collected and concluded that the vast majority of litter on our beaches is locally produced.
The proportion of local litter was greater at Milnerton (99%) than the two False Bay beaches (91% to 94%), where most foreign items came from Asia (mainly Indonesia), carried by the Agulhas Current.
During the 10 days of the level 5 lockdown, the teams collected 13 665 litter items with a total weight of 78.7kg from the three beaches. This amounts to an average of 1 367 new litter items per day along 1 050m of Cape Town’s coastline, which is more than one new litter item a day for each metre of Cape Town’s coastline.
The 10-day study period during level 5 started the day after there was moderate rain on Tuesday, April 21, which resulted in high litter loads at the start of the study window at Milnerton and, to a lesser extent, Sunrise Beach. This is because rain washes all the accumulated litter out of storm drains into the sea.
Litter loads at Muizenberg’s Surfer’s Corner were highest in the middle of the study period, when onshore southerly winds carried in litter from offshore. Most of the non-plastic litter at Milnerton and Sunrise beaches were wooden items, but at Surfer’s Corner in Muizenberg the biggest culprit was glass. There was also no marked decrease in glass in Muizenberg over the study period, despite the beach being deserted.
The glass pieces were all old “beach glass” or fragments of bottles that presumably were exhumed by wave and tidal action every day. Despite no beachgoers, snack-food packets such as sweet and ice-cream wrappers and chip packets accounted for virtually all food packaging.
Straws were outnumbered by lollipop sticks and earbud sticks at all three beaches, with four times as many lollipop sticks as straws on the False Bay coast.
“The study demonstrates the litter that is dropped on land, ends up in our ocean. If you throw your cigarette butt in the street and a chocolate wrapper out of the car window instead of in the bin, it is likely to end up in a stormwater pipe and eventually drain into the ocean. The pollution of our natural environment is everybody’s business, and we all need to do our part to protect our rivers, canals, wetlands, and ocean,” said the City’s mayoral committee member for spatial panning and environment, Marian Nieuwoudt.
The research provides a baseline against which the impact of beachgoers and of litter loads can be estimated for future, and provide novel insights into the four main sources of beach litter, namely:littering by beachgoers, litter from local land-based sources washing ashore through the stormwater system, litter illegally dumped from ships and long-distance drift from other parts of the world.