Mihaela Sima

Sulfide oxidation and acid mine drainage formation within two active tailings impoundments in the Golden Quadrangle of the Apuseni Mountains, Romania

Sulfidic mine tailings have to be classified as one of the major source of hazardous materials leading to water contamination. This study highlights the processes leading to sulfide oxidation and acid mine drainage (AMD) formation in the active stage of two tailings impoundments located in the southern part of the Apuseni Mountains, in Romania, a well-known region for its long-term gold-silver and metal mining activity. Sampling was undertaken when both impoundments were still in operation in order to assess their actual stage of oxidation and long-term behavior in terms of the potential for acid mine drainage generation. Both tailings have high potential for AMD formation (2.5 and 3.7 wt.% of pyrite equivalent, respectively) with lesser amount of carbonates (5.6 and 3.6 wt.% of calcite equivalent) as neutralization potential (ABA=-55.6 and -85.1 tCaCO(3)/1000 t ) and showed clear signs of sulfide oxidation yet during operation. Sequential extraction results indicate a stronger enrichment and mobility of elements in the oxidized tailings: Fe as Fe(III) oxy-hydroxides and oxides (transformation from sulfide minerals, leaching in oxidation zone), Ca mainly in water soluble and exchangeable form where gypsum and calcite are dissolved and higher mobility of Cu for Ribita and Pb for Mialu. Two processes leading to the formation of mine drainage at this stage could be highlighted (1) a neutral Fe(II) plume forming in the impoundment with ferrihydrite precipitation at its outcrop and (2) acid mine drainage seeping in the unsaturated zone of the active dam, leading to the formation of schwertmannite at its outcrop.

Community Perception of Water Quality in a Mining-Affected Area: A Case Study for the Certej Catchment in the Apuseni Mountains in Romania

Mining-contaminated sites and the affected communities at risk are important issues on the agenda of both researchers and policy makers, particularly in the former communist block countries in Eastern Europe. Integrated analyses and expert based assessments concerning mining affected areas are important in providing solid policy guidelines for environmental and social risk management and mitigation. Based on a survey for 103 households conducted in a former mining site in the Certej Catchment of the Apuseni Mountains, western Romania, this study assesses local communities’ perceptions on the quality of water in their living area. Logistic regression was used to examine peoples’ perception on the quality of the main river water and of the drinking water based on several predictors relating to social and economic conditions. The results from the perception analysis were then compared with the measurements of heavy metal contamination of the main river and drinking water undertaken in the same study area. The findings indicate that perception and measurement results for the water quality in the Certej Catchment are convergent, suggesting an obvious risk that mining activities pose on the surface water. However, the perception on drinking water quality was little predicted by the regression model and does not seem to be so much related to mining as to other explanatory factors, such as special mineralogy of rock and soils or improper water treatment infrastructure, facts suggested by the measurements of the contaminants. Discussion about the implications of these joint findings for risk mitigation policies completes this article.

Assessment of Availability and Human Health Risk Posed by Arsenic Contaminated Well Waters from Timis-Bega Area, Romania

Mobilization of As from geological materials into ground and drinking water sources may represent an important threat to human health. The objective of this study was to assess the As concentration and availability in underground water used as drinking water sources. Water samples were collected from public and private wells in Timis-Bega area of Pannonian Basin, West Romania. Total-dissolved As measured after “classical” filtration of water samples was in the range of 0.10–168 μg L−1, thus exceeding the guideline value in majority of the samples. The aim of this study was also to assess the “truly dissolved” concentrations of As considered as available concentrations, in well waters, after passive sampling by Diffusive Gradients in Thin-films (DGT). The results showed that over 70% of total-dissolved As is in available forms. The obtained data were used to evaluate the risks of using the wells as drinking water source. Hazard quotients for ingestion and dermal pathways and hazard index (HI) for exposure to As were calculated. The HI values > 1 found that majority of samples indicated a health risk for local residents.

Chemical modeling of groundwater in the Banat Plain, southwestern Romania, with elevated As content and co-occurring species by combining diagrams and unsupervised multivariate statistical approaches.

The study proposes a combined model based on diagrams (Gibbs, Piper, Stuyfzand Hydrogeochemical Classification System) and unsupervised statistical approaches (Cluster Analysis, Principal Component Analysis, Fuzzy Principal Component Analysis, Fuzzy Hierarchical Cross-Clustering) to describe natural enrichment of inorganic arsenic and co-occurring species in groundwater in the Banat Plain, southwestern Romania. Speciation of inorganic As (arsenite, arsenate), ion concentrations (Na+, K+, Ca2+, Mg2+, HCO3-, Cl-, F-, SO42-, PO43-, NO3-), pH, redox potential, conductivity and total dissolved substances were performed. Classical diagrams provided the hydrochemical characterization, while statistical approaches were helpful to establish (i) the mechanism of naturally occurring of As and F- species and the anthropogenic one for NO3-, SO42-, PO43- and K+ and (ii) classification of groundwater based on content of arsenic species. The HCO3- type of local groundwater and alkaline pH (8.31-8.49) were found to be responsible for the enrichment of arsenic species and occurrence of F- but by different paths. The PO43--AsO43- ion exchange, water-rock interaction (silicates hydrolysis and desorption from clay) were associated to arsenate enrichment in the oxidizing aquifer. Fuzzy Hierarchical Cross-Clustering was the strongest tool for the rapid simultaneous classification of groundwaters as a function of arsenic content and hydrogeochemical characteristics. The approach indicated the Na+-F--pH cluster as marker for groundwater with naturally elevated As and highlighted which parameters need to be monitored. A chemical conceptual model illustrating the natural and anthropogenic paths and enrichment of As and co-occurring species in the local groundwater supported by mineralogical analysis of rocks was established.

Fostering Community Outreach Activities for Environmental Sustainability Through a Cross-Border Academic Research Partnership

The focal aim of this study is to provide a general framework of the role of an academic research partnership in fostering community outreach activities to improve environmental sustainability through developing tailored science-society interfaces. The paper seeks to present an overview of the EU Romania—Bulgaria Cross Border Cooperation Programme project entitled “Romanian—Bulgarian cross-border joint natural and technological hazards assessment in the Danube floodplain. The Calafat-Vidin—Turnu Măgurele-Nikopole sector (ROBUHAZ-DUN)” and, particularly, the research collaboration, scientific outcomes and dissemination activities carried out during the 18 month project. The aim of the paper is to offer an example of how to promote environmental sustainability to community members in a rural transboundary area in order to respond to their needs in terms of hazard assessment and mitigation, but also to increase knowledge and awareness of disaster risk reduction, climate change and environment sustainability. A special attention was paid to the main scientific and informative products (promotional materials, maps, posters, guidebooks, university course, reports) which were used as support materials for the dissemination activities undertaken throughout the project in terms of raising awareness and informative campaigns in schools, meetings with local authorities, joint round tables, media events, summer school etc. These activities were aimed at bridging the gap between the academic research and local communities in an area prone to natural and human-induced hazards in order to support environmental sustainability through disaster risk reduction education.

Geomorphic services for landslide risk evaluation in the RO-RISK Project

The paper presents the steps undertaken within the RO-RISK (Disaster Risk Evaluation at National Level) project with the aim of achieving landslide hazard and risk evaluation at the national level, as well as the close interand transdisciplinary collaboration through the involvement of specialists and stakeholders during the whole research process, the results of which can be assigned to geomorphic services. A common methodology to analyze all the selected risks has been followed within the project, mainly focusing on hazard and impact analyses. At the end, three national and two local scale landslide scenarios have been analyzed into detail in order to provide risk figures as estimations on the location and magnitude of possible physical impacts on the population, the built-up environment and the transportation network, as well as economic and sociopsychological impacts, all of which were needed to finally estimate risk acceptability. Keywords— landslides; risk assessment; geomorphic services; environmental changes; RO-RISK; Romania

Climate Change Projections for a Medium-Size Urban Area (Baia Mare Town, Romania): Local Awareness and Adaptation Constraints

Numerous studies worldwide emphasize the impacts that cities now face due to increasing variability of weather extremes associated with climate change, exacerbating the urban heat island effect, air pollution and health impacts. In this respect, cities need to cope with these new threats and get prepared. One way of doing this is to develop climate change mitigation and adaptation strategies, focusing on local vulnerabilities in relation to the current societal development needs and adaptation options. There are many recent initiatives and examples for climate change adaptation strategies and plans for large cities, but only a few examples for small and medium-size cities. This paper investigates the mid-(2021–2050) and far-future (2071–2100) climate change signals in an urban area located in northern Romania (Baia Mare town), with around 200,000 inhabitants, exploring the results of some CORDEX GCMs under the new IPCC RCPs (RCP2.6, RCP4.5 and RCP8.5). The study analyzes these signals in relation to the local awareness of key institutional stakeholders, as well as to the current social and economic constraints towards considering the climate change adaptation. The findings, based on a survey, highlight how the local authorities perceive and include climate change aspects in their activities as an important step towards real implementation of specific climate-based decisions, as well as their needs in terms of climate information and data. The study provides useful scientific insights about future climate and expected impacts in the Baia Mare Urban System to stakeholders, which could increase their awareness and knowledge in terms of climate change.