SEGH Articles

A pre-mining survey to establish the geochemical baseline in stream water and sediment of a mineralised area in north Greece

02 March 2012

 

One of the lessons learnt by the legacy of mining is that involvement of environmental scientists in the initial planning stages, in geochemistry baseline studies is significant for setting up realistic goals for monitoring and remediation programs.

A recent PhD project in the Department of Economic Geology and Geochemistry at the University of Athens, Greece investigated the geochemical characteristics of surface water and stream sediments of Asprolakkas drainage basin, an area of sulphide mineralization within metamorphic rocks, located in Chalkidiki peninsula, north Greece. One of the research objectives was to establish the geochemical baseline conditions prior to any type of new mining activity. The area represents the only example of active mining and processing of base metal sulphide ore in Greece and also includes an unmined porphyry Cu-Au ore deposit that will be exploited in the near future. In a wider context, this research represents a pre-mining baseline geochemical study that can be used as an analogue for similar metallogenetic provinces in areas with a Mediterranean type climate. The deposits of the area have a long exploitation history that started in 600 BC and continues until today, mainly because of their Au potential. It is believed that the mining activity in Chalkidiki during ancient times was the major source of gold during the era of Fillip II and Alexander the Great.

Concentrations of dissolved major ions and trace metals displayed wide variability within the study area. Kokkinolakkas, the stream draining the exploited Pb-Zn (±Ag) ore bodies, is strongly influenced by chemical weathering of sulphide minerals and presents elevated levels of SO4, Pb, Zn, Mn, Ni, Cd, As and Sb. Stream water of the unmined areas demonstrated a different chemical composition with elevated values mainly for Pb and As. It was found that hydrological conditions are important in modeling the element concentrations in water under present conditions. Major ion content decreases in the wet period as a result of dilution owing to the heavy winter rainfall. A contrasting behavior was observed for heavy metal composition in Kokkinolakkas water samples, due to the enhanced base metal dissolution under high run off conditions. It appears that downstream dispersion of metals is favoured by transport via adsorption processes onto very fine particles (< 0.45 μm). The study also revealed that weathering of the mineral deposits supports the occurrence of a prevalent Fe-Mn oxyhydroxide surface, which is considered to be capable of scavenging toxic metals. However, these precipitates could be a secondary source of trace metals for the water column upon dissolution of the oxides under reduced conditions. Cadmium is the only labile metal indicating the different chemical binding, and higher solubility of this element, compared to the other heavy metals. High actual concentrations were also measured in the carbonate fraction of Kokkinolakkas stream sediment samples, highlighting that pH is the principal variable governing the potential release of these elements to the dissolved phase.

Bearing in mind the ongoing mining developments in the area, results of this study are very significant, providing scientific data about the present environmental-geochemical baseline conditions of the drainage basin and are available for any future comparison. These data can enable mine planners to better anticipate and plan for potential environmental impacts and are useful for setting up realistic goals in monitoring and remediation programs.

Dr Ariadne Argyraki, Assistant Professor in Geochemistry, National and Kapodistrian University of Athens. E-mail: argyraki@geol.uoa.gr 

 Stream water sampling in Chalkidiki, Greece.

Reference

Kelepertzis, E., Argyraki, A., Daftsis, E (2012). Geochemical signature of surface water and stream sediments of a mineralized drainage basin at NE Chalkidiki, Greece: A pre-mining survey, Journal of Geochemical Exploration, 114, 70-81. (doi:10.1016/j.gexplo.2011.12.006)

Keep up to date

SEGH Events

Submit Content

Members can keep in touch with their colleagues through short news and events articles of interest to the SEGH community.

Science in the News

Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

  • Genotoxic effects of PM 10 and PM 2.5 bound metals: metal bioaccessibility, free radical generation, and role of iron 2018-10-09

    Abstract

    The present study was undertaken to examine the possible genotoxicity of ambient particulate matter (PM10 and PM2.5) in Pune city. In both size fractions of PM, Fe was found to be the dominant metal by concentration, contributing 22% and 30% to the total mass of metals in PM10 and PM2.5, respectively. The speciation of soluble Fe in PM10 and PM2.5 was investigated. The average fraction of Fe3+ and Fe2+ concentrations in PM2.5 was 80.6% and 19.3%, respectively, while in PM2.5 this fraction was 71.1% and 29.9%, respectively. The dominance of Fe(III) state in both PM fractions facilitates the generation of hydroxyl radicals (·OH), which can damage deoxyribose nucleic acid (DNA), as was evident from the gel electrophoresis study. The DNA damage by ·OH was supported through the in silico density functional theory (DFT) method. DFT results showed that C8 site of guanine (G)/adenine (A) and C6 site of thymine (T)/cytosine (C) would be energetically more favorable for the attack of hydroxyl radicals, when compared with the C4 and C5 sites. The non-standard Watson–Crick base pairing models of oxidative products of G, A, T and C yield lower-energy conformations than canonical dA:dT and dG:dC base pairing. This study may pave the way to understand the structural consequences of base-mediated oxidative lesions in DNA and its role in human diseases.

  • A systematic review on global pollution status of particulate matter-associated potential toxic elements and health perspectives in urban environment 2018-10-08

    Abstract

    Airborne particulate matter (PM) that is a heterogeneous mixture of particles with a variety of chemical components and physical features acts as a potential risk to human health. The ability to pose health risk depends upon the size, concentration and chemical composition of the suspended particles. Potential toxic elements (PTEs) associated with PM have multiple sources of origin, and each source has the ability to generate multiple particulate PTEs. In urban areas, automobile, industrial emissions, construction and demolition activities are the major anthropogenic sources of pollution. Fine particles associated with PTEs have the ability to penetrate deep into respiratory system resulting in an increasing range of adverse health effects, at ever-lower concentrations. In-depth investigation of PTEs content and mode of occurrence in PM is important from both environmental and pathological point of view. Considering this air pollution risk, several studies had addressed the issues related to these pollutants in road and street dust, indicating high pollution level than the air quality guidelines. Observed from the literature, particulate PTEs pollution can lead to respiratory symptoms, cardiovascular problems, lungs cancer, reduced lungs function, asthma and severe case mortality. Due to the important role of PM and associated PTEs, detailed knowledge of their impacts on human health is of key importance.

  • Interactions between polycyclic aromatic hydrocarbons and epoxide hydrolase 1 play roles in asthma 2018-10-06

    Abstract

    Asthma, as one of the most common chronic diseases in children and adults, is a consequence of complex gene–environment interactions. Polycyclic aromatic hydrocarbons (PAHs), as a group of widespread environmental organic pollutants, are involved in the development, triggering and pathologic changes of asthma. Various previous studies reported the critical roles of PAHs in immune changes, oxidative stress and environment–gene interactions of asthma. EPHX1 (the gene of epoxide hydrolase 1, an enzyme mediating human PAH metabolism) had a possible association with asthma by influencing PAH metabolism. This review summarized that (1) the roles of PAHs in asthma—work as risk factors; (2) the possible mechanisms involved in PAH-related asthma—through immunologic and oxidative stress changes; (3) the interactions between PAHs and EPHX1 involved in asthma—enzymatic activity of epoxide hydrolase 1, which affected by EPHX1 genotypes/SNPs/diplotypes, could influence human PAH metabolism and people’s vulnerability to PAH exposure. This review provided a better understanding of the above interactions and underlying mechanisms for asthma which help to raise public’s concern on PAH control and develop strategies for individual asthma primary prevention.