Microplastic in industrial aquaculture: Occurrence in the aquatic environment, feed and organisms (Dicentrarchus labrax).

The increasing use of plastics and the growing concern about their impact on the environment and living beings makes it necessary to study how microplastics (MP) affect aquaculture systems. In order to gain an in-depth understanding of these systems, this study covers the water intake, the purification treatment at the inlet, the water in the culture tanks, as well as the feed used in the feeding and the organism itself. For this purpose, five samples were taken, both in the water line, feed and sea bass during the weeks of the experiment. It is shown that the available purification systems reduce the amount of MP entering from the receiving environment. However, new MP are observed in the sea bass tank, which may be due mainly to those added through the feed and found in the feed, as well as in the piping and other materials used in current aquaculture systems (PTFE, PA, among others). If focusing on the feed that can reach the consumer, in the case of this study, carried out with sea bass, some types of MP (PE, PTFE, PS and PA) were found in 4 head samples and 4 skin/muscle samples. Although inlet water purification systems manage to reduce a high percentage of MPs in the system, it is observed that there are other access routes that should be considered and reduced in aquaculture facilities to prevent them from reaching the human consumer.

Influence of tourism on microplastic contamination at wastewater treatment plants in the coastal municipality of Chiclana de la Frontera.

The tourism is one of the most important sources of the economy in the Bay of Cadiz. Specifically, the municipality of Chiclana de la Frontera, with a population lower than 90,000 citizens, located in the southeast of Spain. During the summer season the population duplicates leading to an increment in flow at wastewater treatment plants (WWTPs). These facilities have been reported as a source of microplastics (MPs) into marine ecosystems, therefore the aim of the present study is to investigate if the tourism affects the presence, discharge and in the receiving environment. Samples were taken at the influent and effluent of the municipal WWTPs (one located at the urban area and other located at resort area) during 2021 (including low and high season). MPs were collected and extracted from wastewater matrixes following the method recommended by the National Oceanic and Atmospheric Administration and UTS treatment to reduce organic matter and cellulose, respectively. The analysis of the samples was performed according to their abundance, shape, size, and type of polymer, along with the removal rates of MPs at WWTPs. The results showed heterogeneous MPs abundance ranging from 1246.4 to 345.7 MPs/L and 72.9 to 4.2, in the influent and effluent, respectively, increasing the presence of MPs at resort WWTP during high season. Fibers were the predominant shape within all the samples. A total of 17 polymers were identified, by ATR-FTIR, where Acrylates, PE and PA were the largest polymers found. Despite the high MPs retention performance of the WWTPs analyzed (84.1-99.3 %), a combined contribution of approximately 1.4 × 107-5.9 × 108 MPs/d to the aquatic environment was estimated. Finally, these results indicate that the increase of MPs in the wastewater at WWTP-B was related with the population increase as a consequence of summer tourism.