Printed Edition of the Special Issue Published in Toxics

Overview

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Key numbers

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the African continent (4), despite the presence of some of the world’s most notable lakes and rivers.
of which approximately 80% was plastic. Glass, metal and paper were also found at each site, but plastic
bags (22.5–49.4%), personal hygiene products (7.15–18.6%), beverage bottles (1.9–18.8%) and discarded
tilapia (Oreochromis niloticus) and catﬁsh (Bagrus bayad) revealed the presence of MPs in over 75% of the
in a clean-up campaign that took place annually between 2015 and 2018. Approximately 80% of
Mediterranean Sea (9), in Orange County in California (USA, (10)), and a ten year nationwide
of volunteers allows for extensive sampling at a wider range of sites (14) and although data validity
Tanganyika, Lake Malawi holds approximately 25% of the world’s total surface freshwater supply (19).
of ﬁsh present in the lake (19). Perhaps unsurprisingly, approximately 70% of the animal protein
ﬁshing activities; multiﬁlament gillnets (44% of all debris), monoﬁlament gillnets (42%), longlines and
hooks (7%), and ﬂoats (1%). Plastic bags (4%) and clothing (2%) accounted for the remaining solid
plastic particles were recovered from the gastrointestinal tracts of 11 perch (55%) and 7 tilapia (35%),
with spectral analysis conﬁrming the presence of MPs in 20% of each species (24). Together, these two
the other countries that border Lake Malawi (Table 1). The port has various socio-economic activities,
Table 1. Site descriptions.
coast (4), but typical densities reported globally range from 0–2–5 items/m2 (3). An average density of
the number of volunteers to total litter found (values presented in Table 2) resulted in an R2 value
The composition of debris across all beaches was plastic 80.2 ± 5.0%, metal 9.5 ± 2.5%, glass
4.9 ± 3.8%, paper 4.6 ± 4.0%, and construction material 0.9 ± 1.5%. Moreover, the percentages of
that typically more than 80% of anthropogenic litter is comprised of plastics (18). Our study adds data
consistent across sites: plastic carrier bags (22.5–49.4%), personal hygiene products (7.15–18.6%),
beverage bottles (1.9–18.8%), ﬁshing gears (0.21–20.25%), cups (1.9–13.3%), packaging materials
Remaining categories constituted less than 2% of plastic collected. The trend observed at Lake
products contributed to only 1% of plastic items collected in African clean-ups.
(∼46%) with plastic bans (39) and numerous stakeholders are involving themselves in the ﬁght against
debris in Orange County, California. Mar. Pollut. Bull. 2001, 42, 241–245. (CrossRef)
n = 29) and catﬁsh (Bagrus bayad, n = 14). Fish were purchased from local sellers in Cairo, and then
their gastrointestinal tracts were dissected and examined for MPs. Over 75% of the ﬁsh sampled
contained MPs in their digestive tract (MP prevalence of 75.9% and 78.6% for Nile tilapia and catﬁsh,
respectively). The most abundant MP type was ﬁbers (65%), the next most abundant type was ﬁlms
(26.5%), and the remaining MPs were fragments. Polyethylene (PE), polyethylene terephthalate (PET)
isolate MPs. In total, suspected plastics were recovered from the gastrointestinal tracts of 11 perch (55%)
and seven tilapia (35%), and they were conﬁrmed in 20% of each ﬁsh species (i.e., four individuals)
Nile tilapia (n = 29) had an average weight and length of 129.7 ± 59.0 g and 17.7 ± 2.5 cm, respectively,
organic matter with an eﬃcacy of >90% (15,31) whilst importantly having negligible impact on the
particles that were at least 0.5 mm in one dimension. In total, 10% of the collected MPs were identiﬁed
occurrence of MPs (FO%), as follows: FO% = (Ni/N) × 100, where Ni is the number of digestive tracts
Over 75% of the 43 ﬁsh sampled in this study contained MPs in their gastrointestinal tract (33 out
of 43, FO = 76.7%). From these 33 ﬁsh, a total of 211 items of plastic were recovered. The highest
(sample #15, Table S1). The two species showed similar levels of MP prevalence, with FO values of
75.9% and 78.6% for Nile tilapia and catﬁsh, respectively. Of the 22 out of 29 Nile tilapia that contained
4.7 ± 1.7 items (Table 1). This diﬀerence between 7.5 ± 4.9 and 4.7 ± 1.7 items per ﬁsh was signiﬁcant

Methods (brief)

clean-ups from 2015 to 2018. Almost half a million individual items of beach debris were collected,
sampled ﬁsh (9). Similar studies from both marine and freshwater environments showed that this high
level of MP ingestion is rarely found and that ﬁsh sampled from the Nile River in Cairo are potentially
ﬂooding of the Mississippi River caused major freshwater intrusions into the sampled locations. Across
the ten sample sites and seasonal sampling periods, there was considerable spatial and temporal
Lake Malawi. A total of 490,064 items of anthropogenic litter were collected by over 2000 volunteers
data on the anthropogenic debris collected by volunteers on the Malawian coast of Lake Malawi.
In the present, relatively small-scale, study, anthropogenic debris was surveyed and collected
to the little information on anthropogenic and plastic debris collected from freshwater shorelines and
collected during the clean-up at Nkhata jetty in 2018.
Area Covered (m2 ) Volunteers Items Collected Items Collected
before moving to the next stretch. Litter was collected from the shallow water to the highest water
Litter larger than 2 cm was collected by hand, enumerated, and then classiﬁed into categories:
products, were identiﬁed, counted, and collected for disposal. After the clean-up, all recyclable items
A total of 490,064 items of anthropogenic litter were collected by over 2000 volunteers at the
three locations over the four-year period. With reference to the number of items collected, Nkhata
Typically, the numbers of items collected at diﬀerent locations are normalized to the area of the site in
the number of volunteers, the more litter is likely to be collected. Furthermore, in this case where

Implications

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Verification notes

Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing wiki/sources/ pages before creation.
Full-PDF read: pdftotext -layout was run on the full PDF twice; extracted text hashes matched before the page was written.
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Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
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Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised