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Advisor(s)
Abstract(s)
Microplastics are widespread in the marine environment, whereby organisms’ uptake
these tiny particles, presenting adverse biological responses. Plastic debris also act as
a vector of many contaminants which intensify their effects to marine organisms that
depend on type, size, shape and chemical properties. This study aimed to assess the
accumulation and potential toxicity of different sizes of microplastics with and without
adsorbed perfluorooctane sulfonic acid (PFOS) in the clam Scrobicularia plana. Clams
were exposed to 1 mg L-1 of virgin and PFOS (70.2 ± 12.4 μg g−1) contaminated lowdensity
polyethylene microplastics of two different sizes (4-6 and 20-25 μm) over 14
days. Microplastic and PFOS accumulation and filtration rate were determined along
with a multi biomarker approach to access the biological effects of microplastics
accumulation. Biomarkers include oxidative stress (superoxide dismutase, catalase,
glutathione peroxidases), biotransformation enzymes (glutathione-S-transferases)
activity, neurotoxicity (acetylcholinesterase activity), oxidative damage and apoptosis.
Microplastics and PFOS accumulated were microplastic size dependent but not PFOS
dependent and filtration rate was reduced at the end of the exposure. Reactive oxygen
species in gills and digestive gland were generated as a result of exposure to both
types of microplastics, confirming the disturbance of the antioxidant system. Larger
microparticles lead to stronger impacts, when compared to smaller ones which was
also supported by Integrated Biomarker Responses index calculated for both tissues.
An anti-apoptotic response was detected in digestive glands under exposure to any of
the MPs treatments as a probable mechanism associated to carcinogenic responses
derived from MPs uptake.
Description
Keywords
Scrobicularia plana Biomarkers Perfluorooctane sulfonic acid Microplastics Toxicity
Citation
Publisher
Elsevier