Refilwe Mofokeng, Gemma Gerber, Mathew Coote, Sipho Mkhize, Deborah Robertson-Andersson, Gan Moodley. Presented at the Symposium of Contemporary Conservation Practice 2015.

1. Microplastics in marine organisms in KZN:
A new conservation threat?
A representation of studies conducted on microplastics in various countries worldwide showing the number
of publications per country/region.
• UK is the most active country in microplastics research
• Africa has no published studies focusing solely on microplastics to date .
So what does this mean?
80 % of microplastics in Durban are
from domestic sources!
“… medical studies on both
rodents and humans have
also shown that particles of
polyvinylchloride and
polystyrene <150 µm can
translocate from the gut
cavity to the lymph and
circulatory systems.”
Microplastics get consumed by
fish which affect their endocrine
and reproductive systems thus
impacting overall conservation of
aquatic organisms
R.P. Mofokeng, G. Gerber, M.W. Coote, S.K. Mkhize, T. Mkhize, D. Robertson-Andersson, and G.K. Moodley.
University of KwaZulu-Natal (Westville Campus), School of Life Sciences.
What are microplastics?
• Small plastic particles, <5 mm in
size.
• There are two forms of
microplastics (MP) namely; primary
(A1) and secondary (B) MP.
• Primary MP (A1) are found mostly
in cosmetics, plastic beads and
industrial effluent (A2).
• Secondary MP (B) result from
degradation of large plastic debris
which break down over a period of
time.
p <0.0001
F value = 31.98
Stomopneutes Tripneustes
3 X
Conclusion
• All investigated organisms ingested microplastics.
• Microplastics are not only abrasive causing physical harm to organisms, they also tend to accumulate heavy metals and Persistent Organic
Pollutants.
• Microplastics may therefore cause accelerated bioaccumulation of toxins up the food chain thus impacting conservation of aquatic
biodiversity as well as human health.
The solution , however, is in our homes!!!
• 80% of microplastics in Durban's marine waters are beads and fibres, which are present in daily household products such as toothpaste,
facial cleansers, make-up and synthetic fibres.
• Simple behavioural changes such as using alternative products that do not contain microplastics and installing filters in washing machines to
trap fibres from entering aquatic systems are some of the measures that can be taken to reduce the amount of microplastics entering marine
systems.
• This will enhance conservation of aquatic systems, ensuring a healthier and sustainable marine environment.
2 X
X
Microbeads (< 1 mm & 1 – 2 mm) - similar to natural gut retention time
Microbeads (> 5 mm) - 3 x Natural gut retention time (39.6 + 5.8 h)
Microfibres (> 1 mm) - 2 x Natural gut retention (23.8 + 10.4h)
Mussels ingest more plastics with increasing
concentration of microplastics in the water column.
• Sea urchins can take up microplastics through the
madreporite as well as ingesting them.
• The larger the madreporite pore size, the potentially
higher the intake of microplastics.
Globally more than 240million tonnes of
plastic is used each year.
The number of plastics produced now is
around 250 million t.y-1 with a 10 %
annual increase
Mussel: Perna perna
Sea urchins:
Stomopneustes variolaris & Tripneustes gratillaMullet: Mugil cephalus
EFFECTS OF MICROPLASTICS ON AQUATIC ORGANISMS IN THE KZN BIGHT
• Of 187 fish dissected, 34 % had plastics in them
• ALL 16 species caught contained microplastics
• Fish caught in the Durban eddy contained significantly higher microplastic concentrations than
fish caught in Richards Bay or Durban.
• 141 plastic pieces were recovered from fish digestive tracts.
A1
A2
B
Microplastics transport to aquatic
systems?
• Directly introduced into aquatic systems
(freshwater & marine):
• Through drains, sewage, factories, etc.
• Or they are a result of UV degradation
of plastics over time.
Cocktails of toxicants
scorb onto MP particles
PCB
PAH
PBDE’s