S. Acksen et alı 
Marine Pollution Bulletin 228 (2026) 119525 
5 
Br 
23°N 
20°N' 
4 
r 
15°N 
10°N 
CN 
jo 
20°W 15°W 10°W 
A 
10* 
10° 
= 
28 
1078 
. 
Pr 
10'8 
® 
CC 
10° 
) 
30 
n 
220 
10 
A 
nn 
ZoneS _ 
Zone NW 
Zone NE 
DO 
D 
) 250 500 750 1000 
Days before reaching Säo Vicente 
301 
C 
3 Em Zone S 
L— 71 Zone NW 
a L— 7 Zone NE 
"I hm ma 
z 
20 
D 
D 
2 
3 
10 
1 
7 
WET! 
äö 10 20 30 40 
Number of Particles (%) 
Fig. 7. (A) Cumulative heatmap of particles trajectories in front of the West African shelf. Particles from the three release zones are averaged and pathways up to 
.000 days before reaching Säo Vicente were considered. The black line marks the shelf area that is further inspected in (B) and (C). (B) Number of particles (%) at the 
African shelf before reaching Säo Vicente, separated by zones around the island. (C) Number of particles leaving the West African shelf at specific latitudes towards 
Säo Vicente summed 1uD across days 0-1000 before their arrival. Grey tones indicate the zones around Sän Vicente in which the particles would arrive. 
Table 2 
Examples of accumulation rates of debris on beaches worldwide. 
Location Accumulation rate Source 
Säo Vicente, Cabo Verde 0.05 + 0.06 items/m?/d or 0.2 + This study 
0.4 g/m?/d or 0.84 + 0.91 items/m/ 
ior 1262.1 + 2087.6 kg/km/year 
ar 1260 + 1365 items/100 m/15 d 
1445 + 1743 g/m/d or 14.3 + 8 
tem/m/d or 0.0187 + 0.019 m’ /m/ 
4 
10.79 items/km/d 
0. to 29.51 items/m/month 
Sub-Antarctic Island 
beaches 
3arrier islands across the 
1orthern Gulf of 
Mexico 
>oint Pleasant Park, 
Halifax Harbour 
Aapa Nui (Easter Island) 
Jousine Island, 
Seychelles 
Zorfu Island, Ionian Sea 
Eriksson et al. 
2013) 
Wessel et al. 
2019) 
355 (+68 SE) items/month 
0 and 1.90 items/m/day 
3.0082 items/m/d or 2993 items/ 
xm/year 
142 + 115 N/100 m/15 d 
1.77 items/m/d 
2.5-60.2 items/100 m/d 
Walker et al. 
2006) 
Thiel et al. 
42021) 
Dunlop et al. 
2020) 
Prevenios et al. 
(2018) 
Brabo et al. 
(2026) 
Currie et al. 
2023) 
Haarr et al. 
‚20241 
Brazil (Jericoacoara 
National Park) 
Maui, Hawaii 
Lofoten, Norway 
10 items/100 m/d 
Pedro or Palha Carga. As the prevailing wind direction on Säo Vicente is 
northeast throughout the year, winds are most likely the main driver of 
pollution along the north and east-facing coast as they transport floating 
debris from the ocean onto the shores (Guo and Wang, 2019). 
Table 3 
Vlicro- and mesoplastic abundances in beach sediments on other oceanic islands 
ar on the African continent. 
Location Size Average particle Range Source 
range abundance (particles/ 
(mm) (particles/m”) mA 
Säo Vicente 1-10 121.7 
South Africa 2-25 708 
Gran Canaria 1-5 986 
& 
Lanzarote 
Tenerife 1-5 532.8 
0-1694 This study 
0-10,000 Ryan et al. 
(2018) 
Herrera et al. 
(2018) 
Alvarez- 
Hernändez 
et al. (2019) 
Mesoplastic particles were most abundant at the back of the beach, in 
particular at northward oriented sites, also presumably because of winds 
that move light-weighted plastic debris from the shoreline to the back. 
The fact that we found higher macrodebris abundances during the initial 
:leanings than in the follow-up surveys on the beaches in Praia Norte, 
Salamansa and Bafa das Gatas shows a continuous accumulation of 
debris, which increases the load the longer the beach was not cleaned. 
his continuous flux possibly originates from the ocean due to the 
>rientation of the beaches. These three beaches also exhibited higher 
shares of plastic items than the others, presumably because those can 
sasier be transported over long distances by ocean currents. On the 
:;ontrary, Sao Pedro, Palha Carga and Lazareto exhibited higher debris 
‚ates during later surveys than during the initial cleanings. This hints at 
anreliable debris sources, either from land or random entries by sea by 
uıncommon weather and wind conditions. Hence, these beaches also