Linking exposure of mediterranean freshwater ecosystems to pesticides mixtures with their environmental side-effects

• Author(s): Pereira, Ana Carina Santos
• Date: 2017
• Persistent ID: http://hdl.handle.net/10400.5/14958
• Origin: Repositório da UTL
• Subject(s): ecological risk assessment; pesticides; mixtures; modelling; freshwater ecosystem
• Document Type: Doctoral thesis
• Language: English
• Advisor(s): Cerejeira, Maria José; Daam, Michiel Adriaan
• Contributor(s): Repositório da Universidade de Lisboa

Description

Doutoramento em Engenharia do Ambiente - Instituto Superior de Agronomia

In freshwater ecosystems associated with agricultural areas, organisms are exposed to a multitude of toxicologically and structurally distinct pesticides in concentrations that may fluctuate over time. However, the environmental risks of chemicals are traditionally evaluated and regulated on the basis of single substance. Understanding and improving the link between effects and exposure assessment is an important step in the current challenges of risk assessment in order to increase its ecological relevance. To this end, integrated approaches of different hierarchical levels of complexity and ecological realism have been developed and applied, including: exposure modelling, laboratory testing with individual organisms, species sensitivity distribution, ecosystem models and assessment of aquatic community interactions to evaluate the effects of realistic pesticide combinations on water bodies associated with rice, tomato and maize typical agroecosystems of Mediterranean conditions. Contributing to the overall knowledge of the adequacy of the prospective risk assessment and demonstrating that pesticide risk may be underestimated during the actual registration procedure. The data generated in the present study contributed to the derivation of optimized programs of measures under the scope of European legislation; the identification of sites with the highest expected impacts of pesticide mixtures; the evaluation of the major pesticide compounds that contributed mostly to the identified aquatic risks. Furthermore contribute to a deeper knowledge and unravel the effects of co-occurring chemicals, environmental and biological stressors in aquatic ecosystems considering the effects of biotic and abiotic interactions at community and ecosystem levels. The results contribute to reducing the risks of pesticides in freshwater