Author(s): Catarina Mansilha; Armindo Melo; Deolinda Flores; Joana Ribeiro; Joao Ramalheira Rocha; Vitor Martins; Patricia Santos; Jorge Espinha Marques

Linked Author(s): Catarina Mansilha

Keywords: Sao Pedro da Cova coal mine; Coal mine effluents; Irrigation; Polycyclic aromatic hydrocarbons; Potentially toxic elements

Abstract: Water from coal mine drainage is usually connected to a persistent form of pollution. Policies that push towards a restrained use of water for irrigation are not popular among farmers, who are not prepared to respond to drastic increases in water costs, which could decrease the economic profitability of their activities. Therefore, the use of unconventional free water sources, such as mine wastewaters, is regarded as a possible choice. The abandoned São Pedro da Cova coal mine is located in a peri-urban area (NW Portugal), with a landscape consisting of a mosaic of urban, industrial, agricultural, and forest areas. Coal mining effluents from two mine drainage galleries are discharged around 1 km to SE of the mine, producing an ocher-colored sediment which is continuously accumulated in local watercourses (Silveirinhos stream and Ferreira river), and are used for agriculture irrigation. Water samples were collected in Silveirinhos stream and in the mine drainage galleries and were characterized in terms of their suitability for irrigation. Specific water quality parameters were analyzed, including several Potentially Toxic Elements (PTEs) and Polycyclic Aromatic Hydrocarbons (PAHs). The overall quality of groundwater from coal mine drainage revealed pollution. It is very important to raise awareness for rapid intervention in the area due to the evident deleterious impact on local communities. The understanding of the polluted mine water chemistry is fundamental for the design of effective treatment systems, to mitigate the effects of past actions through the development of better management strategies, as well as for reducing environmental and health impacts.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221649

Year: 2022