Determining water and sediment quality related to lead-zinc mining activity

This study focuses on the Koru and Tesbihdere Pb-Zn mining districts, located at the upstream areas of the Umurbey dam basin. Mining activities in Koru, one of the longest operated mines in NW Turkey, date back to the beginning of the 1900s. The purpose of the study is to (1) determine the hydrochemical properties of the water resources and to assess the potential environmental consequences of mining activities in the Koru and Tesbihdere mining districts, and (2) investigate the effects caused by mining activities on the water resources and sediment quality in the Umurbey dam basin. Concentrations of As, Cd, Cu, Fe, Mn, Pb, and Zn in river sediments downstream of the Tesbihdere and Koru mining district, and in the Umurbey dam sediments were higher than the world average for river sediments. The geoaccumulation index and enrichment factor revealed that sediments were strongly polluted with Pb and Zn, moderately to strongly polluted with Cd and moderately polluted with Cu. The chemical analyses of water resources revealed that the maximum Fe, Zn, Pb, Mn, and Cu concentrations reached 2890 μg/l, 1785 μg/l, 1180 μg/l, 984 μg/l, and 419 μg/l, respectively. The Koru River is classifi ed as polluted water according to Turkish inland water quality regulations. The environmental contamination problems in the local drainage system are caused by leakage from past and current tailing ponds into the Koru River. 20 D.S. Yucel, A. Baba basaltic andesite lava, andesitic tuff, rhyodacite and dacitic lava, and tuff. In the upper layers, as well as pyroclastic volcanic rocks, limestone bands are found (Bozkaya and Gokce 2009). This unit is unconformably overlain by Adadagi pyroclastics. Pyroclastic rocks contain agglomerates and tuffs of trachytic, trachyandesitic, dacitic, rhyolitic, and rhyodacitic composition, and andesitic and dacitic lavas containing agglomerates, lapilli stone, and ash tuffs with lava interlayers. Adadagi pyroclastics are exposed in a wide area around the Koru and Tesbihdere mining districts. The corresponding parts of the upper levels of this unit are in the form of layers, silica rich zones, as well as areas with Pb-Zn mineralization and alteration with common brecciation. Adadagi pyroclastics are heavily altered by hydrothermal fl uids; silicifi cation, kaolinization, alunitization, and chloritization are widespread (Bozkaya et al. 2007, Bozkaya and Gokce 2009). Cicek and Oyman (2016) reported that mineralization in Koru and Tesbihdere is commonly observed in the Adadagi pyroclastics, which includes rhyolitic lava-domes and tuffs (Figure 2b). Basalt is the youngest volcanic rock in the form of basaltic lavas and agglomerates, and is represented by the Karaomerler basalt. Karaomerler basalt is composed of basaltic lavas with a hypo-hyaline porphyritic texture, and agglomerate. The basalt unconformably overlies Akcaalan andesite and Adadagi pyroclastics in the northern part of the study area. Alluvium unconformably overlies all the earlier units and is composed of fragments of volcanic and volcano-sedimentary origin, of heterogeneous size, with no diagenesis. Alluvium is generally located along the Koru River. The elevation in the study area has a range of 50–500 m. The Koru and Tesbihdere mining districts have an approximate elevation of 180 m and 370 m above mean sea level, respectively. The Koru and Tesbihdere underground operated mining districts are located at the upstream areas of the Koru River. The Koru River is a tributary of the Umurbey River, which fl ows across the Umurbey plain and eventually fl ows into the Sea of Marmara. Mining activities have caused changes in the hydrology, land cover and land use of mine site. The Koru River is one of the major sources of water for the Umurbey dam. The total length of the Umurbey River is 22 km, the average fl ow rate is 16.777 m3/s, and the river basin area of the Umurbey dam is 279 km2 (Sasi and Berber 2012). Using Pleiades satellite image in December 2016, the dam lake area was calculated to be 1.39 km2. The Umurbey-Koru River confl uence is at a height of 873 m. The Umurbey River has its source in the Dede and Kaplan mountains (Ilgar, 2015). The Umurbey dam is situated along the Umurbey River’s fl ow path. Drinking water for several residential areas is supplied from wells drilled within the fl ood plain of the Umurbey River, including Umurbey village and Lapseki County. The Umurbey dam was established to increase the effi ciency of intensive agriculture in the Umurbey plain area, and to meet the irrigation water requirements of the region. The Umurbey plain is one of the most important areas in Turkey for peach, nectarine, cherry, plum, and apple production. The high quality of the fruit produced provides a large business advantage for both domestic and foreign markets (Ilgar 2015). The water quality in the Umurbey dam and its tributaries is important for providing safe drinking water to the local residents. The aim of this study is to (1) determine the hydrochemical properties of the water resources (the Umurbey dam and its tributaries) and to assess the potential environmental consequences of the mining activities in the Koru and Tesbihdere mining districts and (2) investigate the effects caused by mining activities on the water resources and sediment quality in the Umurbey dam basin. Materials and methods Two water sampling campaigns were conducted (one in the dry season and one in the wet season) to observe seasonal variations. A total of 30 water sampling points from springs, surface water, groundwater, and tailing ponds were selected to determine hydrochemical composition (Figure 3). The discharge rates of springs and surface water were also measured during sampling. Static groundwater levels were measured using an electric sounding device (Eijkelkamp, 30 m) from wells. Groundwater samples were collected using a bailer sampler (Eijkelkamp, 250 ml). Values for pH, temperature and electrical conductivity were recorded by means of a portable multi-parameter fi eld meter (WTW 340i multiparameter). All probes were calibrated at each sampling site before sampling using standard calibrating solutions. Water samples were fi ltered into polyethylene bottles Fig. 1. Location map of Koru and Tesbihdere mine districts and Umurbey dam basin on Google Earth view (December, 2016) Determining water and sediment quality related to lead-zinc mining activity 21 (50 ml*2) using disposable cellulose acetate syringe fi lters of 0.45 μm. Water samples taken for measuring the dissolved phase of metal concentrations were acidifi ed (nitric acid 65% Suprapure®, MERCK, Germany) to pH Fe> Zn> Mn> Pb> Cu> As> Cd, with the following concentration values: Al