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Wastewater surveillance represents an alternative approach to regulating contamination and the early detection of infectious agents and outbreaks of diseases of public health importance. This study evaluated domestic wastewater effects on recreational waters in estuarine and seawater bodies in Guayas and Santa Elena provinces in Ecuador, South America. Fecal indicator bacteria (thermotolerant coliforms) served as key indicators for evaluation. Physical, chemical, and microbiological quality markers following the Ecuadorian environmental quality standard and the discharge of effluents to the water resource were analyzed. Samples were collected from 44 coastal sites and 2 oxidation lagoons during the dry and rainy seasons of 2020 and 2021, respectively. SARS-CoV-2 RNA was detected in samples with higher E. coli concentrations using reverse transcription quantitative PCR to detect the genes N and ORF1ab. All samples analyzed for SARS-CoV-2 showed Ct ˂ 40 for at least one gene. Four samples showed at least 20 genome copies of gene N per reaction. These were at an artisanal fishing port, an estuarine area (Palmar), a recreational bay, and an oxidation lagoon. A moderate correlation was found between SARS-CoV-2 RNA, thermotolerant coliform and E. coli (p-value ≤ 0.0037), and a strong and positive correlation between thermotolerant coliform and E. coli. (p-value ≤ 0.00001), highlighting the utility of these established parameters as a proxy of the virus. Significant differences were found in the concentrations of thermotolerant coliforms between seasons (p-value = 0.016) and sites (p-value = 0.005). The highest levels of coliforms were found in the dry season (63000 MPN/100 mL) in Anconcito and during the rainy season (14000 MPN/100 mL) at Esterillo in Playas County. It is recommended that the decentralized autonomous governments of the surveyed provinces in Ecuador implement urgent corrective actions and establish medium-term mechanisms to minimize a potential contamination route. Additional parameters must be included in the monitoring, such as Enterococcus and intestinal parasites, due to their public health implications. In the oxidation lagoons, maintenance actions must be carried out, including the dissolution of sediments, an increase in water retention times, and in situ treatment of the sludge, to improve the system's performance.

The composition, abundance and distribution of macroplastics (MAPs) and microplastics (MPs) in the Vinces and Los Tintos rivers were determined in three sites (Pueblo Nuevo, Santa Marianita, Los Tintos) from the low basin in the coastal province of Guayas, Ecuador. MAPS were recorded by visual census, covering a total distance of 140 m, and MPs were extracted in the intertidal sediments via density separation using a saturated NaCl solution, and these were counted using a stereomicroscope. A total of 940 plastic items were identified. The predominant debris was plastic with 85.2%, followed by manufactured materials and metals. The Vinces River contained the highest abundance of plastic in the locality of Pueblo Nuevo. The most abundant plastic was MPs. The most common MAPs were plastic bags (23%), food packaging (17%) and foamed plastic (8%). MP size classes quantified between 0.15 and 2.52 mm in intertidal, very fine sandy sediment and decreased in abundance with increasing grain size. The most common MPs were fibres (65.2%) (black (43.8%) and blue (25.8%)), and their distribution has a high correlation with population density and water flow direction: Santa Marianita 5.55 g−1, Pueblo Nuevo 7.39 g−1, Los Tintos 8.17−1. A significant abundance of fibres was identified in Pueblo Nuevo. The plastic spatial distribution revealed major plastic pollution in areas where recreational and tourism activities have been developed. Therefore, we recommend implementing awareness campaigns by educating businesses, residents and tourists on managing solid waste (especially plastic) and wastewater. Our results can serve as a baseline for future plastic monitoring in the area.

This study summarises the diversity of living macroinvertebrates and seaweeds from the intertidal and subtidal rocky shores along Ecuadorian continental coast. Benthic macroinvertebrate communities and seaweeds were quantified over quadrants (50 × 50 cm) randomly placed on transects of 50 m length. A checklist of 612 species was generated: 479 species of macroinvertebrates and 133 species of seaweeds. Groups recorded were Mollusca (184 species), Cnidaria (70), Arthropoda (68), Annelida (60), Echinodermata (42), Chordata (18), Bryozoa (13), Porifera (22), Sipuncula (2), Brachiopoda and Platyhelminthes (only identified as morphotypes). The seaweeds were represented by Rhodophyta (78), Chlorophyta (37), Ochrophyta (13), Cyanobacteria (5) and 19 biotic complexes. Furthermore, 22 new taxa and six alien species were recorded from the intertidal zone. This study provides the first large scale report of benthic communities in different marine coastal ecosystems in mainland Ecuador, covering 1,478 km2 of protected areas and 382 km2 of non-protected areas. The highest benthic diversity was registered in the protected areas and rocky shores from the intertidal zone. The biological data, herein reported, are useful for a long-term monitoring programme to evaluate the status of conservation and to detect rapid changes in the benthic biodiversity from coastal areas.

Reason for addendum: During the preparation of the original manuscript, a scientific work that dealt precisely with Polychaeta as environmental indicators in Patagonia was not considered. This being the first and only work regarding this subject, it was reasonable and necessary to incorporate this information.

Los poliquetos (Annelida) son organismos en íntimo contacto con el sedimento donde viven y el agua sobrenadante. El estrés ambiental genera rápidas respuestas en estos organismos que se refleja en los individuos y sus poblaciones, por lo que se utilizan como indicadores biológicos de disturbios y de calidad ambiental. Los poliquetos han sido ampliamente utilizados en monitoreo ambiental y en bioensayos, y muchos estudios ecotoxicológicos se realizan con poliquetos. En casi todos los hábitats bentónicos estos organismos juegan un papel muy importante en la organización y estructura de las comunidades bentónicas y redes tróficas. Son un ítem fundamental en la alimentación de otros invertebrados y de aves migratorias y peces. Los poliquetos también tienen importancia económica para la industria farmacéutica, y de alimentos concentrados para especies marinas de cultivo (peces y crustáceos), en el campo médico y en la bioingeniería, además de la recreativa (acuarofilia, carnada) y por supuesto para el consumo humano. Varios de los índices de impacto ambiental y calidad ambiental existentes se basan en las características de tolerancia/sensibilidad de los organismos bentónicos, y muchos de ellos son poliquetos. Existen unos pocos trabajos de revisión de estos organismos como indicadores, pero todos en idioma inglés. Este trabajo muestra una actualización de los datos referidos a Latinoamérica y el Caribe, e incluye una amplia revisión bibliográfica.

En la provincia del Guayas se encuentra la mayor población urbana del Ecuador con 3 645 483 habitantes y durante la última década el crecimiento urbano se ha concentrado en el cantón Durán. En ese sentido, las actividades antrópicas se han derivado en urbanismo, al desarrollo agrícola y el industrial, por lo que se han alterado las condiciones normales de los ecosistemas acuáticos adyacentes. En el presente estudio, se determinó la presencia de nitratos, nitritos y amonio en los sedimentos del Estero San Camilo (adyacente al cantón o pueblo de Durán) en noviembre de 2015 durante la época seca. Se realizaron muestreos de sedimentos en cuatro estaciones considerando la principal actividad productiva del área (industrial, urbana y agrícola), en las cuales se colectaron tres réplicas mediante el uso de una draga Van Veen. Se registraron variaciones espaciales significativas (p