The contamination of bivalve molluscs by lipophilic toxins is responsible for human intoxications with manifestations that can be severe. In Portugal, the most common toxins are those of the okadaic acid (OA) group, associated with diarrheic intoxications called DSP (Diarrhetic Shellfish Poisoning). Given the danger of these intoxications, several species of bivalves with commercial interest are analysed weekly at the National Reference Laboratory for Marine Biotoxins of the Portuguese Institute of the Sea and the Atmosphere (IPMA) to assess the occurrence of lipophilic toxins. The capture and commercialization of bivalve molluscs in countries belonging to the European Union is prohibited when the levels of group OA toxins exceeds 160 μg OA equivalent per kg of mollusc. According to IPMA data, the fishing and catching of the shellfish species Donax trunculus in the Eastern Algarve can be interdicted for about 4 months a year, with a higher incidence in the summer months. There is a great impact of this interdiction in economic and social terms, considering the high dependence of this resource in the Eastern Algarve region. In fact, the D. trunculus is emblematic in the Algarve and a regional delicacy, and its consumption has a positive impact on tourism in the region. Contamination of bivalves by toxins of the OA group is associated with many factors, but the phenomenon is not yet fully understood. In the summer period, there is an increase in the local population in the Eastern Algarve that seeks the region for summer vacations, mainly to enjoy the beaches. During this period, the use of sunscreen products by vacationers is recurrent with the purpose of protecting the skin against the UV light that could be highly harmful to health. This consumption will lead to the introduction of a high concentration of organic compounds (with UV filter action) in coastal waters, essentially by the entry of bathers into sea water. Thus, in the summer months there are presumably new (and more) contaminants in the coastal waters of the Eastern Algarve, namely active ingredients of sunscreens, such as oxybenzone, which toxicity in aquatic organisms is scientifically recognized. In this project, it is considered that the D. trunculus will take longer to eliminate okadaic acid in scenarios of co-exposure to oxybenzone, as will occur in the summer on the beaches of the Eastern Algarve. This delay in the elimination of okadaic acid will lead to an increase in the period of interdiction and capture of this valuable resource, with very negative implications at the socioeconomic level. It is also predicted that “greener” sunscreens (e.g., where oxybenzone is replaced by molecules from marine macroalgae) will not have the same effect of slowing down OA metabolism. Therefore, these alternative sunscreens will not have a negative impact on the economic activities dependent on D. trunculus in the Eastern Algarve region (such as fishing, aquaculture, tourism). The confirmation of those two hypotheses will support recommending the replacement of sunscreens with oxybenzone by others “free of this compound”, possibly with molecules provided by marine macroalgae (such as Ulva spp.) in their composition. Awareness actions on the harmful effects of sunscreen ingredients on the environment are foreseen in the project, as well as dissemination activities.