PDF Publication Title:
Text from PDF Page: 015
Review RSC Advances aquatic organisms, especially at environment relevant concen- trations (<1 mg L1, i.e., 0.001 mg L1 or 1 109 MPs per L (ref. 142)) (Table 3). For example, in a mesocosm scenario, the bio- turbation and metabolic activity of lugworms (burrowing invertebrates) in PLA exposures were not different from organ- isms in control treatments, while lugworms exposed to PVC decreased their activity.144 In the same study, the concentrations of microphytobenthos (diatoms) only decreased by a factor of 1.6 in higher dose exposure (2% MPs w/w sediment), in PLA treatments when compared to PVC (2.5).144 Similarly, in a freshwater study, Straub et al.145 reported that the assimilation efficiency (digestive process) of amphipods (invertebrates) was not impaired aer a 4 week exposure to PHB (32–64 mm, ca. 1 mg L1) when compared to organisms exposed to poly- methylmethacrylate (PMMA), but PHB exposure led to body mass loss in amphipods aer 3 weeks. Finally, the reproduction and mortality of water eas was impaired by PLA, but only at extremely high concentrations (EC50 1⁄4 122 mg L1, median effective concentration, for reproduction and increase in mortality (60%) and decrease in adult body length at 500 mg L1).146 Even though the evidence seems to point to a low toxicity of MPs derived from biobased polymers, there is, however, a large gap in the knowledge of these MPs' effects in aquatic organisms. As a consequence, this limited number of ecotoxicological reports and data does not yet allow for a valid and reliable risk assessment of biobased MPs to be performed. Microplastics have the potential to enhance the bio- accessibility of co-contaminants adsorbed onto the surface of particles,149 inducing extra toxicological effects in the biota. Bioaccessibility is dened as the portion of a compound released in the gastrointestinal tract and accessible for absorption.150 Once ingested, the rate of desorption of metals151 or of organic co-contaminants152 from MPs may increase. Enhanced desorption rates can be induced due to the higher ionic strength of biological uids in the gut and to low pH conditions, corresponding to an increased bioaccessibility of substances153 and toxicity of contaminants to organisms. A model approach has shown that hydrophobic organic chem- icals (HOC), sorbed to MPs, can biomagnify (increased bio- accumulation in higher trophic levels) differently in food webs in the marine environment, with PCBs having a lower potential than PAHs due to their physical–chemical characteristics.154 However, the potential bioaccumulation of HOCs induced by MPs is only relevant for diets of over 3% of MPs,154 a condition rarely met in common aquatic habitats, but that could occur in areas of higher MPs concentrations (MPs hot-spots), or in the future due to increased emissions of MPs.132 Even though there is little evidence that MPs increase the bioaccessibility of co- contaminants to organisms when compared with food items, sediments and aquatic media,153,155,156 the interaction of MPs with other toxicants sources is still not fully understood.157 Biobased MPs can differ in adsorption rates of co- contaminants when compared to fossil fuel-based MPs, but their contribution to the bioaccessability of co-contaminants to organisms is unknown. For example, chlorinated phenols adsorption to biobased MPs (PLA) is similar to PE, but lower than PP, in freshwater scenarios.158 Fipronil, a phenylpyrazole © 2021 The Author(s). Published by the Royal Society of Chemistry RSC Adv., 2021, 11, 32917–32941 | 32931 Table 3 (Contd.) Ecotoxicological assessment Biobased polymer Organisms Exposure medium Exposure Effects Reference PLA Water eas (Daphnia magna) Freshwater No induced toxicity (mortality, day of rst brood and number of offspring) Zimmermann et al.147 Yeast Estrogen Screen (YES) and the Yeast Antiandrogen Screen (YAAS) a dilution series 1 : 2 (corresponding to 0.0027–7.5 mg PLA) Exposure to leachates obtained as above, for 20 h (endocrine activity) to a dilution series 1 : 2 (corresponding to 0.0037–7.5 mg PLA) Leachates extracted from 122 mg L1 of MPs in methanol (sonication, 1 h), evaporated and solved in DMSO. Exposure for 21 d Leachates from PLA signicantly induced cytotoxicityPDF Image | Long-term durability and ecotoxicity of biocomposites in marine environments
PDF Search Title:
Long-term durability and ecotoxicity of biocomposites in marine environmentsOriginal File Name Searched:
RA-011-D1RA03023J.pdfDIY PDF Search: Google It | Yahoo | Bing
Development of a solar powered Electric Ship The Electricship website originally started off as a project to develop a comprehensive renewable, affordable, modular electric ship... More Info
Modular Boat Hull Composite The case for a unsinkable, modular composite hybrid boat hull... More Info
MS Burgenstock Hybrid Electric Catamaran Lake Lucerne Unique shuttle servicing Lucerne to the Burgenstock Resort... More Info
Ground Power Unit GPU Powered by Lithium Ion Batteries The goal of the Ground Power Unit is to provide a readily accessible, modular, ready-to-power solution for remote power... More Info
| CONTACT TEL: 608-238-6001 Email: greg@electricship.com | RSS | AMP |