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- Uptake of enrofloxacin from seawater to the macroalgae Ulva and its use in IMTA systemsPublication . Rosa, João; Leston, Sara; Crespo, Daniel; Freitas, Andreia; Pouca, Ana Sofia Vila; Barbosa, Jorge; Lemos, Marco F.L.; Pardal, Miguel Ângelo; Ramos, FernandoIntegrated multi-trophic aquaculture systems can minimize the environmental impacts of aquaculture, while delivering economical benefits. However, the use of extractive species such as seaweeds can accumulate pharmaceuticals commonly used in these systems. Therefore, this work evaluated the exposure of the seaweed Ulva to enrofloxacin (ENR), a vastly used antimicrobial in aquaculture, at two dosages (C1, 7.5 μg L−1 and C2, 15 μg L−1), and concentrations in water and in Ulva were measured through time. Traditional endpoints such as growth and mortality were assessed as ENR effects in the macroalgae. Enrofloxacin presented good stability in seawater, and degradation rates were influenced by the presence of seaweed at the lowest concentration tested. The seaweed was able to assimilate the antibiotic, reaching internal concentrations of 7.76 ± 1.11 ng g−1 WW after 30 min of exposure for C1, and 14.51 ± 1.22 ng g−1 WW, after 15 min for C2. Lowest concentrations detected at the end of experimental time were 4.08 ± 0.42 ng g−1 WW and 5.09 ± 1.57 ng g−1 WW for C1 and C2, respectively, which nonetheless, corresponds to ∼5% of the maximum residue limit established for fish for ENR by the European regulation. The presence of ENR stimulated Ulva growth, with differences observed 96 h after the beginning of the trial.
- Integrated multitrophic aquaculture systems: potential risks for food safetyPublication . Rosa, João; Lemos, Marco F.L.; Crespo, Daniel; Nunes, Margarida; Freitas, Andreia; Ramos, Fernando; Pardal, Miguel Ângelo; Leston, SaraBackground: The demand for fish and fish products is now higher than ever. However, several problems such as nutrient loading or excessive use of resources can be associated with the intensification of aquaculture systems. Integrated multitrophic aquaculture systems (IMTAs) refer to the co-culture of different species belonging to different trophic levels, and offer a sustainable approach to aquaculture development. In these systems, organic and inorganic extractive species will feed on other species waste or on uneaten feed nutrients, acting as bioremediators. Scope and approach: The extractive capacity that these organisms have to take up nutrients from the water also means they will accumulate chemicals that are often administered in intensive productions. The present review describes a vast number of substances that can be found in IMTAs, either intentionally administered or resulting from contamination, and subsequently accumulated in species reared afterwards in these systems. The presence of such chemicals in organisms produced in IMTAs raises several food safety and human health concerns, which need to be addressed. Key findings and conclusions: Although IMTAs still face many challenges in terms of large scale production, legislations are not yet ready to comprise co-cultivation of multiple species in proximity. Also, maximum residue limits already existent for fish must be set for other organisms also produced in IMTAs in order to protect consumer's health. An increase in extractive species consumption (e.g. seaweeds) has been noticed during the past few years, and as IMTAs gain importance as a sustainable production method, food safety issues must be tackled.