The national lockdown offered the City of Cape Town, in partnership with the National Government and the University of Cape Town, a unique research opportunity to learn more about litter on our beaches.
The research opportunity was unique because of the complete absence of beachgoers for the first time ever, due to the lockdown regulations. The City’s Environmental Management Department and the National Government’s Working for Coast Programme partnered with Prof. Peter Ryan’s research team from UCT to make maximum use of this time to learn more about beach litter and where it comes from.
Cape Town beaches used for research
A study was done along the 250m of Table Bay, Milnerton. It was the same site where they have comparative data for 1994/95, 2012 and 2019. The study was done at two 400m stretches of beach on the northern False Bay coast, one at Muizenberg and one east of Sunrise Beach.
Two teams were issued with permits so that they could legally work along these sections for the last 10 days of the Level 5 lockdown – from 22 April to 1 May 2020; and throughout Level 4 of the lockdown.
They collected litter every morning. Each item of litter was washed and dried. They were then categorised in terms of the type of material and weighed. Astonishingly, the oldest item that the team found was a soft drink lid manufactured in 1993. Also, in many cases, it was possible to identify the country of manufacture. Most of the identifiable litter came from local sources (about 94%). As for the rest, the incidence of Asian items was most pronounced among rigid plastic items such as bottle lids and high-density Polyethylene (HDPE) bottles, which can drift long distances at sea. Many more foreign lids carried goose barnacles and bryozoans (81%), indicating they had been at sea for some time, unlike lids from South Africa (8%). Indonesia was the source of most of these items.
Some of the key findings:
- 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.
- This is more than one new litter item per day per metre of Cape Town’s coastline
- The 10-day study period on Level 5 commenced the day after a moderate rain event on 21 April. This 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 Corner were highest in the middle of the study period. Due to the onshore southerly winds carried in a litter from offshore
- Plastic items, including foamed plastics and cigarette butts, accounted for 92% to 99% of litter items by number, and 85% to 94% by mass
- Most of the non-plastic litter came from wooden items at Milnerton and Sunrise Beach, but the glass was most prevalent at Muizenberg Corner, accounting for 6% of all litter items (13% of mass). Interestingly, there was no marked decrease in glass at Muizenberg Corner over the 10-day study period, despite the beach being deserted. The glass pieces were all old ‘beach glass’ or fragments of bottles that presumably were exhumed by a wave and tidal action every day
- Despite the lack of beachgoers, on-the-go snack food packets such as sweet and ice-cream wrappers and chip packets accounted for virtually all food packaging, as is also typical of street litter
- 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. Soft drink bottle lids were 15 times more abundant than PET drink bottles. Although ropes and other shipping-related litter contributed only a modest proportion of the number of litter items (1% to 7%), they comprised 30% to 70% of the mass of plastic on beaches mainly due to large marine items
- Compared to data from previous studies of daily accumulation at Milnerton and Muizenberg, litter loads were not much lower during the lockdown, because most litter washes ashore, rather than being left by beachgoers. Despite the lower litter levels on land during the lockdown, there appears to have been enough residual litter trapped in stormwater drains to keep litter levels at ‘normal’ levels at least through the end of April
- The country of manufacture was identified for almost 1 400 items collected during the 10-day accumulation studies. A majority of items were from local sources. This excluded items known to be imported into South Africa, for example, sweets from Brazil, Turkey, Malaysia, and McDonald’s tomato sauce sachets from Egypt.
- It is clear that even without beachgoers, we are locally responsible for the vast majority of litter on our beaches. 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
Research shows that litter is everyone’s business
City’s Mayoral Committee Member for Spatial Planning and Environment, Alderman Marian Nieuwoudt, explained that the waste that is left on land will eventually end up in the ocean.
“Thus, 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 storm water 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.”
The research provides a baseline against which we can estimate the impact of beachgoers on litter loads in future. The research 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 dumped from ships
- long-distance drift from other parts of the world
“This research is crucial as it will help us understand where plastic and other pollution in the ocean come from. By identifying the sources of pollution, we can develop and implement programmes and actions to address this problem.”