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: 

 Stream water sampling in Chalkidiki, Greece.


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

  • Assessment of the toxicity of silicon nanooxide in relation to various components of the agroecosystem under the conditions of the model experiment 2018-08-18


    Investigation of SiO2 nanoparticles (NPs) effect on Eisenia fetida showed no toxic effect of the metal at a concentration of 250, 500 and 1000 mg per kg of soil, but conversely, a biomass increase from 23.5 to 29.5% (at the protein level decrease from 60 to 80%). The reaction of the earthworm organism fermentative system was expressed in the decrease in the level of superoxide dismutase (SOD) on the 14th day and in the increase in its activity to 27% on the 28th day. The catalase level (CAT) showed low activity at average element concentrations and increase by 39.4% at a dose of 1000 mg/kg. Depression of malonic dialdehyde (MDA) was established at average concentrations of 11.2% and level increase up to 9.1% at a dose of 1000 mg/kg with the prolongation of the effect up to 87.5% after 28-day exposure. The change in the microbiocenosis of the earthworm intestine was manifested by a decrease in the number of ammonifiers (by 42.01–78.9%), as well as in the number of amylolytic microorganisms (by 31.7–65.8%). When the dose of SiO2 NPs increased from 100 to 1000 mg/kg, the number of Azotobacter increased (by 8.2–22.2%), while the number of cellulose-destroying microorganisms decreased to 71.4% at a maximum dose of 1000 mg/kg. The effect of SiO2 NPs on Triticum aestivum L. was noted in the form of a slight suppression of seed germination (no more than 25%), an increase in the length of roots and aerial organs which generally resulted in an increase in plant biomass. Assessing the soil microorganisms’ complex during introduction of metal into the germination medium of Triticum aestivum L., there was noted a decrease in the ammonifiers number (by 4.7–67.6%) with a maximum value at a dose of 1000 mg/kg. The number of microorganisms using mineral nitrogen decreased by 29.5–69.5% with a simultaneous increase in the number at a dose of 50 mg/kg (+ 20%). Depending on NP dose, there was an inhibition of the microscopic fungi development by 18.1–72.7% and an increase in the number of cellulose-destroying microorganisms. For all variants of the experiment, the activity of soil enzymes of the hydrolase and oxidoreductase classes was decreased.

  • Seasonal characteristics of chemical compositions and sources identification of PM 2.5 in Zhuhai, China 2018-08-16


    Fine particulate matter is associated with adverse health effects, but exactly which characteristics of PM2.5 are responsible for this is still widely debated. We evaluated seasonal dynamics of the composition and chemical characteristics of PM2.5 in Zhuhai, China. PM2.5 characteristics at five selected sites within Zhuhai city were analyzed. Sampling began on January 10, 2015, and was conducted for 1 year. The ambient mass concentration, carbon content (organic and elemental carbon, OC and EC), level of inorganic ions, and major chemical composition of PM2.5 were also determined. Average concentrations of PM2.5 were lower than the National Ambient Air Quality Standard (NAAQS) 24-h average of 65 μg/m3. The daily PM2.5 concentration in Zhuhai city exhibited clear seasonal dynamics, with higher daily PM2.5 concentrations in autumn and winter than in spring and summer. Carbon species (OC and EC) and water-soluble ions were the primary components of the PM2.5 fraction of particles. Apart from OC and EC, chemical species in PM2.5 were mainly composed of NH4+ and SO42−. There was a marked difference between the summer and winter periods: the concentrations of OC and EC in winter were roughly 3.4 and 4.0 times than those in summer, while NH4+, SO42−, NO3, and Na+ were 3.2, 4.5, 28.0, and 5.7 times higher in winter than those in summer, respectively. The results of chemical analysis were consistent with three sources dominating PM2.5: coal combustion, biomass burning, and vehicle exhaust; road dust and construction; and from reaction of HCl and HNO3 with NH3 to form NH4Cl and NH4NO3. However, additional work is needed to improve the mass balance and to obtain the source profiles necessary to use these data for source apportionment.

  • Estimates of potential childhood lead exposure from contaminated soil using the USEPA IEUBK model in Melbourne, Australia 2018-08-14


    Soils in inner city areas internationally and in Australia have been contaminated with lead (Pb) primarily from past emissions of Pb in petrol, deteriorating exterior Pb-based paints and from industry. Children can be exposed to Pb in soil dust through ingestion and inhalation leading to elevated blood lead levels (BLLs). Currently, the contribution of soil Pb to the spatial distribution of children’s BLLs is unknown in the Melbourne metropolitan area. In this study, children’s potential BLLs were estimated from surface soil (0–2 cm) samples collected at 250 locations across the Melbourne metropolitan area using the United States Environmental Protection Agency (USEPA) Integrated Exposure Uptake Biokinetic (IEUBK) model. A dataset of 250 surface soil Pb concentrations indicate that soil Pb concentrations are highly variable but are generally elevated in the central and western portions of the Melbourne metropolitan area. The mean, median and geometric soil Pb concentrations were 193, 110 and 108 mg/kg, respectively. Approximately 20 and 4% of the soil samples exceeded the Australian HIL-A residential and HIL-C recreational soil Pb guidelines of 300 and 600 mg/kg, respectively. The IEUBK model predicted a geometric mean BLL of 2.5 ± 2.1 µg/dL (range: 1.3–22.5 µg/dL) in a hypothetical 24-month-old child with BLLs exceeding 5 and 10 µg/dL at 11.6 and 0.8% of the sampling locations, respectively. This study suggests children’s exposure to Pb contaminated surface soil could potentially be associated with low-level BLLs in some locations in the Melbourne metropolitan area.