Interdisciplinary Centre of Marine and Environmental Research

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Diverse Arbuscular Mycorrhizal Fungi (AMF) communities colonize plants inhabiting a constructed wetland for wastewater treatment

Publication . Calheiros, Cristina S. C.; Pereira, Sofia I. A.; Franco, Albina R.; Castro, Paula M. L.

Constructed wetlands (CWs) are biological wastewater treatment systems that comprise several components where plants and associated organisms play an important role in water depuration. Microbial studies emphasize bacterial dynamics, whereas studies of arbuscular mycorrhizal fungi (AMF) are scarce and the functional role of AMF in aquatic and wetland plants is poorly understood. The aim of this study was to analyze the AMF communities colonizing the roots of Canna indica, Canna flaccida, and Watsonia borbonica inhabiting a CW treating wastewater of a tourism unit. The dynamics of the AMF communities were evaluated by Denaturing Gradient Gel Electrophoresis (DGGE) of 18S rRNA gene amplification products along cold (C) and hot (H) seasons for three consecutive years. DGGE profiles allowed the estimation of AMF species richness (S), and Shannon-Wienner (H) and Pielou (J) indexes, for the different plant species, showing differences between species and along the years. Excised bands from DGGE were analyzed and identified through sequencing for arbuscular mycorrhiza, revealing the presence of AMF strains closely related to Glomus sp., Rhizophagus sp. and Acaulospora sp. genera. Concomitant water quality analyses showed that the system was effective in organic and nutrient removal during the sampling period. Findings from this study suggest that AMF diversity found in the CW is influenced by the water constituents, season, and plant species.

2019Journal article

Open access

Toxicity abatement of wastewaters from tourism units by constructed wetlands

Publication . Calheiros, Cristina S. C.; Castro, Paula M. L.; Gavina, Ana; Pereira, Ruth

The present research intended to investigate the toxicity abatement of domestic wastewater after passing a biosystem composed of a constructed wetland (CW) followed by a pond. The wastewater was generated in a tourism house in a rural and mountainous context and passed through a septic tank before being diverted to a CW followed by a pond. A battery of ecotoxicological tests, comprising microalgae (Raphidocelis subcapitata), macrophytes (Lemna minor), cladocerans (Daphnia magna), and bacteria (Aliivibrio fischeri), was used to assess the toxicity of the wastewater collected before and after the CW and the water of the pond. Physicochemical parameters (pH, conductivity, chemical oxygen demand, biochemical oxygen demand, total suspended solids, phosphates, ammonium, and nitrate) were also determined. The CW was able to remove carbon and nutrients from the water with a concomitant reduction of its toxicity. This study, reinforced the added value of using toxicity tests as a complement to CW operational monitoring to validate the solution and to analyze possible readjustments that may be required to improve efficiency. This study lends further support to the claim that CWs can be a sustainable solution for treating small volumes of domestic wastewater in a rural context.

2019Journal article

Open access

Dataset of the preparation and characterization of an artificial sludge for ecotoxicological purposes

Publication . Gavina, Ana; Freitas, Ana Cristina; Ricardo, Amadeu; Gomes, Ana; Marques, Catarina; Lopes, Isabel; Pereira, Ruth

This work describes the protocol developed for preparing an artificial digested sludge to be used for the ecotoxicological evaluation and risk assessment of chemical substances that are previewed to attain the soil through sewage sludge applications for fertilization (e.g. pharmaceutical compounds). Such evaluations have been made with standard protocols for ecotoxicological tests with terrestrial species in which the chemical substances are directly spiked to the test soil. This procedure lacks ecological relevance in terms of the role the sludge organic matter plays on the bioavailability and fate of chemical substances. Here we describe the protocol and the composition for obtaining the artificial sludge, prepared with commercial pet food and eggs white to mimic the composition of domestic sewage sludge in terms of proteins, carbon hydrates, fat and fibers content. Further, the conditions ascertained for the anaerobic digestion of the organic mixture are described, and the final properties of the sludge are presented, after repeating the procedure twice.

2019Journal article

Open access