Browsing by Author "Keiter, Steffen"
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- Influence of particle size on ecotoxicity of low-density polyethylene microplastics, with and without adsorbed benzo-a-pyrene, in Clam Scrobicularia planaPublication . Rodrigues, Ana Rita; Mestre, Nélia; FONSECA, TAINÁ; Pedro, Paulo; Carteny, Camilla C.; Cormier, Bettie; Keiter, Steffen; Bebianno, Maria JoãoThis study investigated the ecotoxicological effects of differently sized (4–6 µm and 20–25 µm) low-density polyethylene (LDPE) microplastics (MPs), with and without adsorbed benzo-a-pyrene (BaP), in clam Scrobicularia plana. Biomarkers of oxidative stress (superoxide dismutase—SOD; catalase—CAT), biotransformation (glutathione-S-transferases—GST), oxidative damage (lipid peroxidation—LPO) and neurotoxicity (acetylcholinesterase—AChE) were analysed in gills and digestive glands at different time intervals for a total of 14 days of exposure. In order to have a better impact perspective of these contaminants, an integrated biomarker response index (IBR) and Health Index were applied. Biomarker alterations are apparently more related to smaller sized (4–6 µm) MPs in gills and to virgin LDPE MPs in the digestive gland according to IBR results, while the digestive gland was more affected by these MPs according to the health index.
- Perfluorooctane sulfonic acid (PFOS) adsorbed to polyethylene microplastics: accumulation and ecotoxicological effects in the clam Scrobicularia planaPublication . Islam, Naimul; FONSECA, TAINÁ; Vilke, Juliano Marcelo; Gonçalves, Joanna M.; Pedro, Paulo; Keiter, Steffen; Cunha, Sara C.; Fernandes, José O.; Bebianno, Maria JoãoMicroplastics 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.