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This study had the support of the Fundação para a Ciência e a Tecnologia (FCT) through MARE: UID/MAR/04292/2019; CESAM: UID/ AMB/50017/2019, FCT/MCTES through national funds, the co-funding by the FEDER within the PT2020 Partnership Agreement and Compete 2020; Project PROTEOME (PTDC/AAG-MAA/1302/2014) co-financed by COMPETE (POCI-01-0145-FEDER-016773). The project was also partially funded by the Integrated Programme of SR&TD “SmartBioR” (reference Centro-01-0145-FEDER-000018) co-funded by Centro 2020 program, Portugal2020, European Union, through the European Regional Development Fund. Hugo R. Monteiro, Sara C. Novais, and João L.T. Pestana wish to acknowledge the financial support given by FCT (SFRH/BD/80988/2011, SFRH/BPD/94500/2013, IF/01420/2015, respectively). Spinosad and indoxacarb are two relatively new insecticides mainly used in agriculture to control insect pests. However, at their current application rates, non-target aquatic insect species may also be impacted. In this study, larvae of the non-biting midge Chironomus riparius were exposed in the laboratory to both insecticides and their effects evaluated at the organismal level, using standard ecotoxicological tests, and at the biochemical level, by monitoring specific oxidative stress, neuronal, and energy metabolism biomarkers. Chronic exposure to both insecticides compromised growth and emergence of C. riparius. Short-term exposures revealed alterations at biochemical level that might be related to the toxicological targets of both insecticides. Growth and development time were the most sensitive endpoints at individual level for both pesticides, while at the biochemical level, the electron transport system activity was the most sensitive biomarker for spinosad exposure, suggesting an increase in energy demands associated with the activation of defense mechanisms. Glutathione-S-transferase was the most sensitive biomarker for indoxacarb exposure, underlining the role of this enzyme in the detoxification of indoxacarb. Additionally, changes in lactate dehydrogenase and glutathione peroxidase activities were observed for both insecticides, and evidences of oxidative damage were found for spinosad. This study contributes to the growing knowledge on sublethal effects of novel insecticides on non-target aquatic invertebrates and strengthens the usefulness of biochemical biomarkers to support the interpretation of their potentially deleterious effects on aquatic insects near agricultural fields. info:eu-repo/semantics/publishedVersion

This PhD thesis focuses on the investigation of iron oxide nanoparticles (IONP). Due to the increasing application of iron nanomaterials (NM) in environmental remediation of contaminated sites, tons of these NM will consequently be released to the environment with unknown risks to biota. For assessing effects of IONP, Daphnia magna was used since there are several standardized test protocols available. Due to its sensitivity against most pollutants and its filter-feeding way of life Daphnia is a preferred organism for testing NM in aquatic ecotoxicology. The presented studies show the influence of coating materials and colloidal properties on the effects of IONP on Daphnia in acute and chronic tests. In a further study, the use of IONP for remediation applications and the risk/benefit for the environment from this technique was studied in combinatory exposure acute tests. Furthermore, the Daphnia acute test was critically revised and possible miniaturizations and prolongations are shown.

A short-term Tisbe battagliai toxicity test design was used to assess the potential eco- logical effects of pollutants in coastal marine communities. By exposing nauplii and reproductive females over 4 and 6 d, respectively, to 3 toxic substances (fluoranthene, cypermethin and delta- methrin), the bioassay was seen to successfully measure survival effects on egg, nauplii and adults and sublethal effects on food acquisition and clutch size. Predictive consequences of toxic exposure at population level was estimated in terms of reproductive success, by integrating effects on adult survival and reproductive performance over the studied exposure period. Fluoranthene exposure reduced feeding rate and clutch size at concentrations below those affecting survival and population responses. For cypermethrin, survival, sublethal and reproductive success concentration effects were of a similar magnitude. For deltamethrin adult and nauplii survival, clutch size and reproductive suc- cess were equally affected at concentrations which were lower than those affecting feeding and egg survival. Responses to contaminated algae showed a different pattern, with toxicant effects only on nauplii survival and reproductive success, and under exposure to pyrethroid insecticides. Thus, dif- ferences in the dominant ecotoxicological modes of action, in terms of the balance between survival and sublethal responses with potential effects at the population level, could be successfully assessed using this short-term bioassay. These results have important implications for risk assessment in estu- arine and coastal waters because with relatively short-term, and thus cost-effective tests, the func- tional relationship between effects on survival, feeding and reproduction rates and concentration can be determined.