During the course of the project, the project partners from the Institute of Natural Resources and Territorial Planning (INDUROT) at the University of Oviedo conduct several field monitoring campaigns at this site. These activities are part of work package 1 and will help set an initial basis for comparison, as well as track how remediation efforts evolve in real conditions on site. The site is also relevant for work package 2, in which the strategies will be optimised for example with nanobiophytoremediation techniques.
The Nitrastur case study:
phytomanagement strategies for the post-industrial landscape
Langreo in Asturias has been one of Spain’s key industrial hubs since the 19th century. This 20-hectare megasite hosted coal mining and coal-fired power stations, as well as steel and chemical industries. The Nitrastur fertiliser plant, one of Spain’s largest brownfield sites, significantly contributed to the region’s pollution before it was abandoned in 1997. The site is primarily contaminated by arsenic (As) and lead (Pb), together with other metal(loid)s such as zinc (Zn), cadmium (Cd) and copper (Cu). The fine-grained pyrite ashes spread across the site and mixed with the natural soil are a major source of contamination. Other pollutants include slag, coal waste, hydrocarbons and polycyclic aromatic hydrocarbons (PAHs).
At the Nitrastur site, pHYBi is building on past remediation projects starting from 2016, such as the LIFE I+DARTS, NANORM and REGROUND projects. In these projects birch and willow trees have already been planted and are now evaluated for their phytoextraction and phytostabilisation qualities. The use of bioaugmentation and biomass-derived amendments, such as bacterial inocula, is being evaluated in the context of soil phytoremediation. New experimental plots are being trialled, as well as the application of nano-amendments in laboratory settings for nanobiophytoremediation.
Different campaigns track soil evolution at the Nitrastur site
Throughout the project, three field monitoring campaigns are being conducted to evaluate changes in soil properties, the availability of contaminants, the performance of vegetation and the production of biomass. These surveys collectively document the long-term evolution of the site, both before and after the implementation of new phytomanagement strategies in real field conditions.
The first monitoring campaign revealed significant variation in contaminant levels across the site. 13 years later, however, there was no clear relationship between plant growth, metal(loid) accumulation in leaves and bacterial community composition, and either contaminant concentrations or the historical treatments.
From historic plots to future soil solutions
During this year’s field sampling, the INDUROT team, Verónica Peña-Álvarez, Lidia Moriano, Salvador Sánchez, Rubén Alba-Álvarez, Arantza Heredia-Bilbao and José L. R. Gallego, revisited the historic plots that were established 13 years ago. Soil and plant samples were collected for analysis of contaminant concentrations, soil properties linked to soil health, and microbial communities using metagenomics. Tree height and biomass were estimated using 3D laser scanning, and plant health indices were assessed using drone-based multispectral imagery.
In addition to the long-term monitoring campaigns, pHYBi is developing new pilot-scale phytomanagement approaches at Nitrastur. The results of these monitoring campaigns are helping to inform the design of new field experiments at Nitrastur. These experiments will test phytomanagement strategies adapted to the local area, combining organic amendments, nanoscale materials and microbial inocula. The aim is to improve soil health, reduce contaminant availability and support plant growth under real field conditions.