|Environmental impact of mining activities in the eastern Mediterranean Sea|
Varnavas, S.P. (2000). Environmental impact of mining activities in the eastern Mediterranean Sea, in: Balopoulos, E.T. et al. (Ed.) International conference. Oceanography of the eastern Mediterranean and Black Sea. Similarities and differences of two interconnected basins, Zappeion international conference Centre, Athens, Greece, 23 to 26 February 1999. pp. 412-413
In: Balopoulos, E.T. et al. (Ed.) (2000). International conference. Oceanography of the eastern Mediterranean and Black Sea. Similarities and differences of two interconnected basins, Zappeion international conference Centre, Athens, Greece, 23 to 26 February 1999. Research in Enclosed Seas Series, 8. EC: Brussel. ISBN 92-828-9019-8. 494 pp., more
In: Research in Enclosed Seas Series. Office for Official Publications of the European Communities: Luxemburg, more
|Author|| || Top |
Objectives and MethodologiesThe aim of the work is to assess the enviromental impact of sulphide mining activities in the Mediterranean region in view of the leaching of sulphide related elements such as Fe,Cu,Zn, Pb,As,Cd from mine tailing. The following research methodology was used-Geochemical mapping of the distribution of sulphide related elements such as Fe,Cu,Zn,Pb,As,Cd arround the mine tailings.-Chemical and mineralogical analysis of mine tailings in order to determine the input of metals in the surrounding environment.-Soil analysis with regard to heavy metal content, water movement and adsorption of metals in sedimends.-Study of the uptake of metals by plants (root vegetables), growing in the neighbourhood of the tailings and modelling of heavy metal distribution in soils and streams.-Modelling the behaviour of metals in streams (water and sediments).-Sampling of sea water, sediments and beach sands at coasts close to mining activities.Results-The results of this work have provided a comprehensive picture of the environmental situation around mining sites in the Mediterranean region.-Together with the depend understanding of the related processes this has provided a better base for any management decisions and land use activities in these areas, including agricultural or horticultural use of contaminated soils.-A model to calculate the transport of metals from mineral waste in the Limni Mine area, Cyprus to the Chrysochou bay has been developed. Model calculations show that the bulk of copper transported to the bay is particulate, and chemically inert. Cadmium on the other hand is transported mainly in chemically active form. The model is capable of reproducing reasonably weIl the measured sediment composition of the Limni stream. Model calculations further show that the water composition with respect to dissolved constituents at the mouth of the Limni stream is fairly constant, mainly due to the very high alkalinity of the headwater (7-7.5 meq/l), which is capable of neutralising large quantities of acid mine drainage water. Therefore, the pH of the Limni water at the point where it enters the sea is always (in the calculation) between 7.9 and 8.35. In the period following a (simulated) rainfall event of 200 mm in the mountains east of the Limni mine, about 2 tons of copper are transported to the Chrysochou bay from the Limni stream alone.-The soils occurring in the vicinity of the Limni mine mineral waste in which wheat and peanut are cultivated are markedly polluted with Cu, Zn, Cd, Mo, Se, As and Cd.-Significant toxic metal enrichments were found in cultivated plants.-Of the metals related to the toxic solid waste Cd, Si, Cu and Fe accumulate in a higher degree in the roots than in the remaining parts of the plant. By contrast Zn and Mn accumulate in a higher degree in the upper part of the plant than in the roots.-It is revealed that large quantities of mineral waste were dispersed on the beach being a constant source of toxic metals to the marine environment.Copper and Zn are markedly enriched at the seawater beach interface whereas As is mostly enriched at the upper zone of the beach.-Pyrite content in the Limni Mine beach reaches 65.4%, while at 2OOm offshore it reaches the value of 24%.-The acid mine drainage waters of the tailings contain significant amounts of Fe, Cu, Zn and S indicating the continuous release of these elements from the mining tailings during the wet season and their dispersion in the surrounding area.-The coastal seawaters are enriched in dissolved Fe, Zn and Cu relative to eastern Mediterranean seawaters indicating that the released Fe, Cu and Zn from the mining tailings reach the marine environment.-In the seafloor sediments, significant amounts of Fe, Mn, Cu, Zn, Pb and Ni are present in the acetic acid souble fraction indicating that they are loosely held in the sediments. It is therefore implied that significant amounts of the above metals have recent I y accumulated on the seafloor .-A large part of the bay is influenced by the chemical weathering of the waste since it is covered by sediments rich in metals identical to those encountered in the waste ( i.e. Cu, Pb, Co, Mn, Zn ).-The stream sediment analysis showed that the streams Argaki Limni and Argaki Karioulasi are the main paths through which significant amounts of metals such as Cd, Cu, Ni, Cr, Zn are dispersed away from the waste mounds.-Significant enrichments of Cd, Cu, Ni, Cr and Zn were located in the stream sediments very close to the coast. -The EDT A leaching analysis have shown that the above metals are easily removable from the sediments. Therefore, they enter the surrounding soils during the wet season in the soluble form. In addition, they may enter the marine environment both incorporated in the transported sediments and in the dissolved form.Conclusions-Since it has been revealed that the chemical weathering of the mineral waste affected a large part of the surrounding the mining area, including areas where food production takes place a priority should be given in carrying out the necessary research for the stabilization and the prevention of further weathering of the mineral waste, the degree of which increases very rapidly.-The application of a pilot plant towards the remediation of all areas where food production takes place such as the soils and the coastal zone is of high priority .This can be achieved by the identification of the appropriate earth material which should be used in the metal-rich soils for inactivating the metals and their prevention to get into the food chain.-The exact quantities of toxic metals taken by the population with their food should be determined.-The study of dispersion of toxic metals by dust to the urban environment, marine and agricultural environment is of great importance.-The influence of the mineral waste on the seafood and the fish should be investigated.