Miguel Ángel Álvarez-Vázquez

Contributions of trace elements to the sea by small uncontaminated rivers: Effects of a water reservoir and a wastewater treatment plant

Trace element contributions from small rivers to estuaries is an issue barely addressed in the literature. In this work, freshwater flowing into the Ria of Cedeira (NW Iberian Peninsula) was studied during a hydrological year through the input from three rivers, one considered uncontaminated (the Das-Mestas River), a second affected by urban treated wastewater discharges (the Condomiñas River), and the third containing a water reservoir for urban supply (the Forcadas River). With the objective of assessing the possible influence of human pressure, the annual yields for selected trace elements (Al, Fe, As, Cd, Co, Cr, Cu, Mn, Mo, Ni and Pb) were estimated and compared by normalizing by basin surface. Both dissolved and particulate transported elements were considered. After the data treatment and analysis it can be highlighted that: (i) the Das Mestas River is suitable to be included between the short European pristine baseline of small rivers, at least regarding the transported trace elements; (ii) natural enrichments were identified associated to the lithology of the basin in the Das-Mestas River (i.e. As) and in the Condomiñas River (i.e. Co, Cr and Ni); this fact highlights the importance of considering the local background for a proper assessment; (iii) the impoundment in the Forcadas River is related with a general decrease, even depletion, of the particulate and dissolved transported trace elements, except Mn; (iv) the discharge of sewage to the Condomiñas River is increasing the inputs to the ria of some trace elements in the particulate phase (i.e. Al, Cu and Pb). Both observed human-induced changes can be regarded as typical disturbances of trace element contributions from small rivers to estuaries.

Inventory and Assessment of Fluvial Potholes to Promote Geoheritage Sustainability (Miño River, NW Spain)

The Miño is the most important river in the NW Iberian Peninsula. When it flows through Ourense town (Spain), the attractiveness of the thermal springs hides the importance of the fluvial potholes developed over bedrock. These forms reflect the strength of erosion processes, linked to fluvial incision over time. Potholes have an environmental, didactic, socio-economic and cultural potential. In order to promote their integration within territorial heritage, this research is focused on a place-based knowledge and practice. This study aimed to define the meanings and interests of fluvial potholes, regarding their sustainable uses as georesources and offering fit information for the key social actors to assist territorial development. An inventory of sculpted forms was carried out in an urban reach of the Miño River. After the site diagnosis and form characterisation, a set of fluvial potholes (82 cases) was identified within the thermal area. The assessment of the geomorphological and use/management interests delivered their values as resources for territorial sustainability. Ten potholes, selected from a preliminary list and identified through the methodology, have a potential for education, leisure and recreation. Actions designed to raise awareness of the interests and values of these geodiversity components are also presented.

Possible impact of environmental policies in the recovery of a Ramsar wetland from trace metal contamination

The Umia-Grove Intertidal Complex is located within the Ria of Arousa (NW Iberian Peninsula). Out of its significance for wintering shorebirds it has been included in the Ramsar List of Wetlands of International Importance as well as in international protection networks such as the European Natura 2000 and Important Bird and Biodiversity Areas-BirdLife International. In a sediment analysis conducted in the year 1999, the wetland was found to have been contaminated by potentially toxic trace metals, to wit: Cr, Cu, Ni, and Pb. Sediment samples retrieved in 2014 to make an updated assessment of the condition of the ecosystem showed evidence of the presence of selected trace elements, namely, Cd, Co, Cr, Cu, Ni, Pb, and Zn, within or slightly above the background ranges of local, regional, and general references. In the 15-year time frame between the two samplings there has been noticeable change in the relationship between nature and society as a consequence of the entry into force of a number of regulations aimed at avoiding the emission of contaminants; among others, the ban of Pb in gasoline, the deployment of wastewater treatment plants according to the European Water Framework Directive, and the limitation of the use of Cu pesticides. With the ensuing drop of human pressure, the self-purifying capacity of the ecosystem has effectively contributed to the wetlands recovery. Nevertheless, the application of a normalized enrichment factor to the more recent set of samples suggests the presence of relict low contamination by Cd, Cu, and Ni in localized areas. The compared analysis of the wetland condition in the two years is a sign of the success of the policies and regulations for environmental protection, but further work and more effectiveness are necessary in order to preserve threatened ecosystems of such importance as the Umia-Grove wetland.

Landform values for rural sustainability: Recognition and assessment in a Spanish–Portuguese border region case study

Abstract Landform assemblages may be used to define sites of geomorphological interest which are resources for rural sustainability. This paper focuses on the valuation and significance of such sites in the context of one European internal border region, illustrated using a case study from the inland mountains of the Spanish-Portuguese border: the Serra do Larouco. The theoretical and methodological approach used includes the recognition, inventory and assessment of a preliminary list of twenty-eight sites. They comprise diverse granitic landforms which characterise the rural inland landscapes in the North West of the Iberian Peninsula. The results from the qualitative and quantitative assessments were the basis for a final selection of nine sites as significant land resources. An analysis of their key values supports the proposal of different use and management options to promote rural sustainability. A review of the methodology applied and the consideration of other case studies provide a means to interpret and discuss the regional and local significance of the selected sites. The conclusions emphasise the crucial role that values linked to landforms can play in little-known mountainous and rural border regions, suggesting a future research agenda.