Alper Baba

THE EFFECT OF YATAGAN THERMAL POWER PLANT (MUGLA, TURKEY) ON THE QUALITY OF SURFACE AND GROUND WATERS

Yatagan thermal power plant consumes annually 5.4 million tons of coal and the annual production capacity of the plant is 3.78 billion KWh. The thermal power plant uses 15 000 tons of coal and discharges 5000 tons of fly and bottom ash daily to the disposal site. The waste is dumped using conveyer belts and pipes into a dam founded on metamorphic rocks. However, as the waste hills formed, the water level reached the karstic marbles that over lay schist. Water leaches through dried waste hills and karstic marbles, ultimately adversely affecting the quality of ground and surface waters. The concentrations of major and minor ions were determined on water samples taken at 2 points in the dam, 5 points in surface water and at 21 points in groundwater located in the vicinity of the waste disposal site, total of 28 samples, for three years. The chemical analyses revealed that the concentrations of Ca2+, Cd2+, Pb2+, Sb2+ and SO42- in some samples exceed the Turkish Drinking Water, the U.S. EPA and WHO limits. Isotope analyses were carried out to determine the origins of waters, which showedthat contamination is taking place in the vicinity of the waste disposal site.

Groundwater contamination and its effect on health in Turkey

The sources of groundwater pollution in Turkey are identified, and pathways of contaminants to groundwater are first described. Then, the effects of groundwater quality on health in Turkey are evaluated. In general, sources of groundwater contamination fall into two main categories: natural and anthropogenic sources. Important sources of natural groundwater pollution in Turkey include geological formations, seawater intrusion, and geothermal fluid(s). The major sources of anthropogenic groundwater contamination are agricultural activities, mining waste, industrial waste, on-site septic tank systems, and pollution from imperfect well constructions. The analysis results revealed that natural contamination due to salt and gypsum are mostly found in Central and Mediterranean regions and arsenic in Aegean region. Geothermal fluids which contain fluoride poses a danger for skeleton, dental, and bone problems, especially in the areas of Denizli, Isparta, and Aydın. Discharges from surface water bodies contaminate groundwater by infiltration. Evidence of such contamination is found in Upper Kızılırmak basin, Gediz basin, and Büyük Melen river basin and some drinking water reservoirs in İstanbul. Additionally, seawater intrusion causes groundwater quality problems in coastal regions, especially in the Aegean coast. Industrial wastes are also polluting surface and groundwater in industrialized regions of Turkey. Deterioration of water quality as a result of fertilizers and pesticides is another major problem especially in the regions of Mediterranean, Aegean, Central Anatolia, and Marmara. Abandoned mercury mines in the western regions of Turkey, especially in Çanakkale, İzmir, Muğla, Kütahya, and Balıkesir, cause serious groundwater quality problems.

Naturally occurring arsenic in terrestrial geothermal systems of western Anatolia, Turkey: Potential role in contamination of freshwater resources

Arsenic (As) contamination in terrestrial geothermal systems has been identified in many countries worldwide. Concentrations higher than 0.01 mg/L are detrimental to human health. We examined potential consequences for As contamination of freshwater resources based on hydrogeochemical investigations of geothermal waters in deep wells and hot springs collected from western Anatolia, Turkey. We analyzed samples for major ions and trace element concentrations. Temperature of geothermal waters in deep wells showed extreme ranges (40 and 230 °C), while, temperature of hot spring fluids was up to 90 °C. The Piper plot illustrated two dominant water types: Na-HCO3(-) type for geothermal waters in deep wells and Ca-HCO3(-) type for hot spring fluids. Arsenic concentration ranged from 0.03 to 1.5mg/L. Dominance of reduced As species, i.e., As(III), was observed in our samples. The Eh value ranged between -250 and 119 mV, which suggests diverse geochemical conditions. Some of the measured trace elements were found above the World Health Organization guidelines and Turkish national safe drinking water limits. The variation in pH (range: 6.4-9.3) and As in geothermal waters suggest mixing with groundwater. Mixing of geothermal waters is primarily responsible for contamination of freshwater resources and making them unsuitable for drinking or irrigation.

Environmental Impact of the Utilization of Geothermal Areas

Turkey is one of the fastest growing power markets in the world and is facing an ever-increasing demand for power in the coming decades. Geothermal is one of its important renewable energy sources; Turkey is rated the 7th country in the world in terms of geothermal potential. The countrys installed capacity is 992 MWt for direct use and 20.4 MWe for power production. These are expected to almost triple in the next ten years and more than quadruple in the next twenty years. Geothermal energy is generally accepted as being an environmentally benign energy source. Geothermal development over the last forty years in Turkey has shown that it is not completely free of impacts on the environment. Environmental impacts are projected to limit the use of this needed energy resource. Geothermal waters of Turkey are highly mineralized with elevated levels of arsenic (As), boron (B), cadmium (Cd), and lead (Pb), resulting in scaling and corrosion. Because they are not reinjected, geothermal discharges also result in an observed contamination of soil and waterways. Reinjection is recommended to be installed as a standard procedure to avoid these adverse impacts.

Groundwater quality and hydrogeochemical properties of Torbali Region, Izmir, Turkey.

The large demand for drinking, irrigation and industrial water in the region of Torbalı (Izmir, Turkey) is supplied from groundwater sources. Almost every factory and farm has private wells that are drilled without permission. These cause the depletion of groundwater and limiting the usage of groundwater. This study investigates spatial and temporal change in groundwater quality, relationships between quality parameters, and sources of contamination in Torbalı region. For this purpose, samples were collected from 10 different sampling points chosen according to their geological and hydrogeological properties and location relative to factories, between October 2001 and July 2002. Various physical (pH, temperature, EC), chemical (calcium, magnesium, potassium, sodium, chloride, alkalinity, copper, chromium, cadmium, lead, zinc) and organic (nitrate, nitrite, ammonia, COD and cyanide) parameters were monitored. It was observed that the groundwater has bicarbonate alkalinity. Agricultural contamination was determined in the region, especially during the summer. Nitrite and ammonia concentrations were found to be above drinking water standard. Organic matter contamination was also investigated in the study area. COD concentrations were higher than the permissible limits during the summer months of the monitoring period.

Statistical Analysis of Causes of Death (2005–2010) in Villages of Simav Plain, Turkey, With High Arsenic Levels in Drinking Water Supplies

The purpose of this research was to compare the causes of death in 5 villages situated in Simav Plain, Turkey, during 2005–2010 where different arsenic levels were detected in drinking water supplies. Since groundwater in Simav Plain had arsenic concentrations that ranged between 7.1 and 833.9 ppb, a two-phase research was formulated. In the first phase, public health surveys were conducted with 1,003 villagers to determine the distribution of diseases. In the second phase, verbal autopsy surveys and official death records were used to investigate the causes of death. In total, 402 death cases were found in the study area where cardiovascular system diseases (44%) and cancers (15.2%) were major causes. Cancers of lung (44.3%), prostate (9.8%), colon (9.8%), and stomach (8.2%) were comparably higher in villages with high arsenic levels in drinking water supplies. Furthermore, the majority of cases of liver, bladder, and stomach cancers were observed in villages with high arsenic levels.

GEOMORPHOLOGICAL INVESTIGATION OF THE EXCAVATION-INDUCED DÜNDAR LANDSLIDE, BURSA — TURKEY

Abstract. This paper discusses the occurrence and development of the excavation‐induce deep‐seated landslide, which took place near Dündar village, located west of Orhaneli town in northwestern Turkey. The event occurred in the Bursa‐Orhaneli lignite field, which has been actively operating since 1979. Due to undermining of a gently inclined slope (10°) to extract a coal seam, primary tension cracks, which were precursors of the movement, were first observed in the northern head area in mid‐ to late October 2003. This movement happened simultaneously with precipitation that was significantly above long‐term average measured at a nearby climatology station (Keles). This precipitation amount is characterized statistically by a significant standardized anomaly of 1.6. The majority of the monthly precipitation total in October 2003, which mainly consisted of rain showers and thunderstorms, occurred in the last week of the month. By April 2004, rotational failure continued intermittently. After a relatively wet (rainy and snowy) period from January 2004 to April 2004, the main rotational slump occurred in late April 2004, causing the entire destruction of Dündar villages cemetery. Daily climatic and synoptic meteorological data have proved that heavy showers in late April may had triggered the last slump by producing rain showers of 19.3 mm and 19.9 mm daily total on 27 and 28 April 2004, respectively. Field observations carried out along the main head scarp have shown that the slope failure was facilitated by a pre‐existing normal fault with an east‐ west direction and 80° dip. Grain‐size analysis showed that the failure occurred on clayey silt, which forms 55% of the slip surface material. Based on the evidence from X‐ray fluorescence and energy dispersive X‐ray spectroscopy results, smectite‐type clay ‐ a product of the chemical weathering of tuff ‐ was the main constituent of the slip surface material. The landslide occurred over an area of 600 m × 650 m with a total volume of 8775 000 m3. Approximately 28 hectares of farm land were entirely destroyed and the excavated coal seam was buried. The mining operation was moved to 100 m north of the landslide area near Gümüşpınar village. From morphological evidence, it is concluded that excavation activities caused the failure to extend in more than one direction as an enlarging sliding mechanism; this produced a high landslide risk for Gümüşpınar village, where the most significant normal fault with a 75 m vertical displacement in a coal‐bearing sequence is found in the lignite field.

The impact of an open waste disposal site on soil and groundwater pollution

A study has been carried out of a waste disposal site, located in the valley of a small creek, 3 km south of Canakkale city centre. The surface area of the site was around 101000 square metres, and the total amount of waste deposited at the site since 1990 was approximately 1001000 tons. The major risks of the dump are its closeness to the university campus area to the south, the airport to the north, and residential areas encroaching towards the dump site. The nuisance caused by odour is high. The waste pile emplaced at the head of the tributary stream has caused channelling of the leachate to the creek, which is eventually washed towards the agricultural fields. The field investigation included surface geological, hydrogeochemical and geochemical studies. Water samples were collected at 11 points. Three observation wells were dug in front of the open waste disposal site. Soil samples from these observation wells were collected at 30, 70 and 150 cm depths, and some heavy metals were analysed. The concentrations of lead, copper and zinc in soil at the depth of 150 cm decreased with distance from the waste disposal site. Hydrogeochemical data analysis gave similar results.

Hydrochemical and Isotopic Composition of Tuzla Geothermal Field (Canakkale-Turkey) and its Environmental Impacts

Tuzla is an active geothermal area located in northwestern Turkey, 80 km south of the city of Canakkale and 5 km from the Aegean Coast. Geothermal brine, deriving from this area, contains an abundance of NaCl and a water temperature of 173°C (T1 well at 814 m depth) is typically encountered. The aim of this study was to determine the hydrogeochemical properties of the geothermal brine using both chemical and isotopic data, and to investigate the origin of the geothermal brine in the Tuzla area and the environmental impacts of Tuzla Geothermal Field (TGF). Both geothermal brine and shallow groundwater in the area are of meteoric origin. Isotope results indicate that the hot saline waters (brine) in the Tuzla geothermal field originate from connate water along faults. As the saline water rises to the surface, it mixes with shallow groundwaters in various ratios. In addition, the high sodium (Na) and chloride (Cl) content in the Tuzla Stream, fed from the Tuzla geothermal brine during the dry season, cause an increase in sodium and chloride concentrations in the shallow groundwaters by infiltration into the aquifer. Moreover, salt accumulation on the surface is observed due to the uncontrolled artesian flow of geothermal brine, which adversely affects the salinity of shallow groundwater.

Environmental and Exergetic Aspects of Geothermal Energy

Geothermal energy is already in the form of heat, and from the thermodynamic point of view, work is more useful than heat because not all heat can be converted to work. Therefore, geothermal resources should be classified according to their exergy, which is a measure of their ability to do work. In recent years there has been a remarkable growth of interest in environmental issues—sustainability and improved management of development in harmony with the environment. Environmental impact assessment is one of the most widely used tools in environmental management. In this study, the environmental and exergetic aspects of geothermal energy, namely the rapid impact assessment matrix method, and, specific exergy index, were studied first. They were then applied to the Tuzla geothermal field in Canakkale and Balcova geothermal field in Izmir, Turkey, respectively. Finally, the results obtained are given and discussed.