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Spatial environmental risk evaluation of potential toxic elements in stream sediments

Publication . Antunes, I.M.H.R.; Albuquerque, M.T.D.; Roque, Natália

The occurrence of Potential Toxic elements (PTE) in a river system is influenced by different factors such are geology, mineralogy, hydrology, vegetation, chemical reactivity, land use pattern and biological productivity. In the herein study – Monfortinho area (Central Portugal) - stream sediments were used as a tool for contamination evaluation and definition of PTE enrichment clusters. The assessment of the studied PTE distribution and the evaluation of the associated ecological risk is the target goal of the herein study and went through a two-step methodology: 1. Data collection and preparation; 2. Spatial modeling and definition of spatial clusters of high (high rings) and low (low rings) significance. For this last issue, was adopted a geostatistical approach, namely variography for attributes spatial structure computation, Ordinary Kriging for content inference aiming to predict the variables’ values at any arbitrary spatial location within the study region; and finally, clusters definition using the Local G clustering algorithm. A broad discussion about PTE provenance and possible trends in spatial dissemination lead to the conclusion that the Monfortinho area is far affected by the mining legacy. It is worth noticing the Fe; Ni; Ba; Cu; B; Zn; V; Pb and As enrichment overlapping the areas of old abandoned Ba-Zn mineralizations (southern area) and the sedimentary gold concentrations along the Erges river banks (northern region). The multivariate geostatistical approach allowed the identification and quantification of anthropogenic impacts and therefore the definition of adequate monitoring actions for the contaminated zones. Future work involves an exhaustive identification of covariates to tackle PTE fate as well as to as to clarify their provenance and enrichment.

2018Journal article

Restricted access

New thermal mineral water from Aguas (Penamacor, Central Portugal): hydrogeochemistry and therapeutic Indications

Publication . Gomes, L. Ferreira; Antunes, I.M.H.R.; Albuquerque, M.T.D.; Silva, A. Santos

Thermal mineral waters are a potential resource in the local and economic development of a region. The thermal area of Termas das Águas is in the inner region of central Portugal and its grant will enable the exploration and exploitation of this water resource for medical and therapeutic purposes through a thermal medical SPA. In Portugal, the classification and legalization of a thermal unit must provide a natural mineral water resource, recognized by Portuguese Energy and Geology General Directorate and integrated in a concession granted by the Portuguese Government. For this purpose, it will be necessary to have available mineral water, with physico-chemical and microbiological, temporal stability, ensuring water’s high quality. The purpose of a certified mineral water includes a detailed geomorphological, geological and hydrogeological characterization of the survey area, as well as the water's compositional temporal stability. Only after the recognition conferred by the national agency as a natural mineral water, it is possible to start a medical-hydrological study, for this resource. This process follows an experimental period of 3 years, during which it is implemented the different and specific balneotherapy techniques associated with the therapeutic features of the mineral water. A final report, to be submitted to Portuguese General Directorate for Health, will gather the main results and conclusions, regarding the benefits of this natural resource on human health, and allow its inclusion as an official medical thermal SPA in the Portuguese Normative Decrees. The main subject of this research is the geological and hydrogeological characterization of Termas das Águas aquifer, as well as the mineral water quality study (AM4 – well). The main topics for the medical hydrological study, mainly related to rheumatic and respiratory diseases, are also presented to the medical SPA of Termas das Águas.

2019Book part

Open access

Predictive scenarios for surface water quality simulation: a watershed case study

Publication . Antunes, I.M.H.R.; Albuquerque, M.T.D.; Oliveira, Sandrina Fidalgo; Sanz-Lobón, Germán

Surface water is exposed to contaminants which change the natural hydrological parameters and consequent contaminant dispersion. Water self-depuration is an ecological process aiming to restore the natural watercourse balance, which depends on the quality and quantity of topical and diffuse contributions. The main goal of this research is the evaluation of surface water quality in the Águeda River (Portugal-Spain transboundary watershed) and its self-depuration ability considering different predicted scenarios. Biochemical oxygen demand (BOD5), dissolved oxygen (DO), dry residue, Ptotal, Ntotal, pH, temperature and microbiological parameters were analyzed, in thirty-six surface water samples. Simulation of different quality scenarios was undertaken using Qual2Kw software and the river's self-depuration ability discussed. The obtained model's calibration achieved a score of 95% confidence interval, for almost analyzed parameters. The calibrated model was used for two prediction scenario construction. The first one, intending to assess the influence of topical contaminated discharge and the second one, aiming to evaluate the influence of minimum flow rates, representing an extremely dry year. The two considered scenarios revealed that self-depuration capacity is more affected by the presence of minimum flow rates than topical discharges, attesting a large potential for self-depuration along the Águeda River.

2018Journal article

Restricted access

Effects of wastewater treatment plant’s discharges on a freshwater ecosystem: a case study on the Ramalhoso River (Portugal)

Publication . Almeida, Pedro Dinis Nunes; Albuquerque, M.T.D.; Antunes, I.M.H.R.; Ferreira, Ana Maria; Pelletier, Gregory

Sewage discharges constitute severe stress in freshwater ecosystems. The Ramalhoso River belongs to the Tagus River watershed and was chosen for a pilot study on the impact of wastewaters discharges in a freshwater ecosystem and its ability for self-depuration. Twelve water samples were collected along the river and were georeferenced. The first point is located upstream of the first discharge point, the second one corresponding to the discharge flow, and all the other samples located downstream of secondary inflows at approximately equal distances. Three sampling campaigns were conducted during the rainy winter (January), the intermediate conditions (March), and the dry season (June). The following chemical parameters were analyzed: biochemical oxygen demand for 5 days (BOD5), dissolved oxygen concentration (DO), total phosphorus (Ptotal), total nitrogen (Ntotal), pH, temperature, total suspended solids (TSS), microbiological parameters (MP), and flow determination. Dissolved oxygen, BOD5, and TSS were used as indicators of environmental pollution. A coupled hydrodynamic and water dispersion model simulated different pollution scenarios using the QUAL2kw software to construct a water quality model. The simulation results are consistent with field observations and demonstrate that the model has been correctly calibrated, allowing feasibility studies of different treatment schemes and the development of specific monitoring activities.

2021Journal article

Restricted access