- Email: [email protected]
Geo-environmental site investigation for Tunceli, Turkey municipal solid waste disposal site
Engineering Geology 159 (2013) 76–82
Contents lists available at SciVerse ScienceDirect
Engineering Geology journal homepage: www.elsevier.com/locate/enggeo
Geo-environmental site investigation for Tunceli, Turkey municipal solid waste disposal site Ayten Öztüfekçi Önal a, 1, Deniz Demirbilek b, 1, Veysel Demir b,⁎ a b
Department of Geological Engineering, Tunceli University, Tunceli, Turkey Department of Environmental Engineering, Tunceli University, Tunceli, Turkey
a r t i c l e
i n f o
Article history: Received 8 August 2012 Received in revised form 12 March 2013 Accepted 18 March 2013 Available online 28 March 2013 Keywords: Solid waste Site investigation Unsanitary storage Environmental geotechnics
a b s t r a c t The environmental and geological condition of a current solid waste disposal site in the city of Tunceli, Turkey was investigated. Improper geological structure and soil properties of this unsanitary solid waste storage site as well as leachate from this site caused significant pollution in air, soil, and surface water. Natural soil characteristics and geology of the site are presented in this paper. Petrographic properties of vulcanized rubber rocks composed of tuff and volcanic sandstone at the bottom of storage sites and the mineralogical composition of the base composed of these rocks were examined. Permeability of the natural soil and index properties were determined using soil mechanics experiments (moisture content, specific gravity, Atterberg limit tests, sieve analysis, hydrometer analysis, falling-head permeability test, and standard proctor test) conducted on disturbed samples collected from excavated sites and the relationship between mineralogical composition and soil hydraulic behavior was investigated. Natural soil samples of six different parts of the site indicated that, the soil class in four samples is silty sands, sand–silt mixtures, one is clayey sands, sand–clay mixtures and one is clayey silts with slight plasticity. The values obtained using permeability tests for subsoil samples vary from 10−5 to 10−8 cm/s. Low permeability (10−7 and 10−8 cm/s) at the south part of the site increases to 10−5 cm/s at the natural soil of the North side. Extensively faulted and fissured volcanic sandstone levels at the site give potential to waste leachate to reach deep levels. The soil composition, hydraulic conductivity, topographic conditions, and other location criteria in the current solid waste disposal site showed that the current disposal site is not suitable for this purpose. © 2013 Elsevier B.V. All rights reserved.
1. Introduction Unsanitary solid disposal sites have been generally considered as an irregular solution of the waste disposal problem and most of them are used without sufficient geological, hydrogeological and environmental assessments. Environmental problems are expected to occur if no secure and environmental friendly measures associated with development are carried out (Bruno, 2007; Depountis et al., 2009). A significant source of natural soil, water, and air contamination can be caused from municipal and environmental waste disposal sites. There have been many studies conducted to prevent the pollution of the surface and groundwater from solid waste's leachate (Wright et al., 1988). Different geoenvironmental site investigation techniques can be applied to assess possible contamination from waste disposal sites (Mondelli et al., 2007). To minimize environmental risk factors, sanitary solid waste disposal sites are constructed after sufficient geological and environmental
⁎ Corresponding author. Tel.: +90 428 213 1794; fax: +90 428 213 1861. E-mail addresses: [email protected] (A. Öztüfekçi Önal), [email protected] (D. Demirbilek), [email protected] (V. Demir). 1 Tel.: +90 428 213 1794; fax: +90 428 213 1861. 0013-7952/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.enggeo.2013.03.014
assessments such as geotechnics of the site, hydrogeology, seismicity, etc. (Simsek et al., 2005; Sener et al., 2011). Open dumping is a common practice in Turkey. Around 67% of the generated municipal solid waste has been dumped at open dumps (Nas et al., 2008). Environmental problems caused by solid disposal such as odor problems, release of gases to atmosphere, risk of explosion or fire, uncontrolled leachate to surface and groundwater, and undesired visual pollution can easily be seen in these types of sites. In addition to these problems, even medical waste can be found in these sites. A site that is planned to become a sanitary landfill must initially be evaluated and assessed in details based on mineralogical and index properties of the subsoil and geological formations such as rock types, tectonic properties, the depth of groundwater level, etc. According to the solid waste control regulation of Turkey dated 1991 (14.3.1991-20814; amendment 05.04.2005-25777) the depth of the groundwater level must be at least 30–50 m and subsoil should have low permeability (10−8 m/s) thick clay segment or natural subsoil should have between 10 −6 and 10 −8 cm/s permeability (Chapius, 1990). An impermeable zone separating aquifer and subsoil of the site can block leaching process from the wastes. The current practice is to try hydraulical isolation of the waste in order to minimize the adverse effects of the disposal site on groundwater (Kayabali, 1996).
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
In the city of Tunceli, there is no sanitary solid waste disposal site. Currently all types of municipal wastes including medical waste have been deposited in an irregular way to the unsanitary solid disposal site. No environmental or geological assessments or any treatment of the site's natural soil was performed during selection of this site. The purpose of this study is to provide an assessment of current site's geology through a determination of the mineralogical composition and index properties of subsoil of the site, to indicate environmental risk factors and to draw attention to possible future environmental problems resulting from this site. To achieve these goals, the disposal site's geological map was created and samplings were performed to determine microscopic features of rock units and mineralogical composition of subsoil of the site. 2. Materials and methods Since some pollutants such as trace elements occur naturally in rocks and soils, the mineralogical composition of the sub-soil and rocks at the site was investigated to find out possible contaminant potential of the site's basin. This mineralogical composition study was also aimed to find out the content of minerals having high specific
77
surface value like clay minerals in subsoil of the site that can absorb the contaminants or became natural barrier blocking or retarding the spread of pollutants to the groundwater. To name rock units with microscopic analysis, fifteen volcanic rock samples were collected from solid waste sites and adjacent areas. To determine structural and mineralogical composition and index properties of natural soil of the site, six holes (C-1 to C-6) were excavated at six different points at the site as shown in Fig. 1. After the excavation, a piece of tarp was laid at the bottom of each hole and disturbed soil samples were taken with shaving soil from surface to the bottom of the hole. Samples were named from DZ-1 to DZ-6 (Table 1). To determine main minerals of cohesive subsoil of the site, the X-Ray Diffractometry (XRD) analysis of the DZ samples was constructed at Inonu University's (Malatya) Scientific Research Laboratory (IBTAM). The XRD resolves and microscopic studies of soil and volcanic rock samples were performed at Tunceli University Geology Department's Laboratory. Determination of specific gravity (ASTM D-854 (2000)), moisture content (ASTM D-2216 (1998) and TS 1900 (1997)), Atterberg plastic and liquid limits (ASTM D-4318 (2000) and TS 1900 (1997)), standard proctor test and sieve, hydrometer, and falling head permeability analysis (ASTM standard analysis) were completed.
Fig. 1. Geological map of the unsanitary solid disposal site and surrounding area at the city of Tunceli. from C-1 to C-6: prospect locations of sampling holes; DA: sampling locations of microscopic study.
78
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
Table 1 Mineral composition of natural soil of the site. Abbreviations are the same as those used in Fig. 5. Mineral composition Sample no. Coordinate
Sm/A P Q Hb O S
DZ-1 DZ-2 DZ-3 DZ-4 DZ-5 DZ-6
x x x x x x
39°6.850′N–39°36.266′E 39°6.843′N–39°36.250′E 39°6.754′N–39°36.290′E 39°6.763′N–39°36.374′E 39°6.744′N–39°36.498′E 39°6.746′N–39°36.371′E
x x x x x x
x x x x x x
x x x x x x
B H G D C
x x x x x x
x x
x x
x
x x
3. Results and discussion The solid waste disposal site in the city of Tunceli, Turkey and its surrounding areas' rock formations and other geological properties were investigated. A map showing the location of the municipal disposal site in Tunceli and the location of the studied transect is seen in Fig. 1. To determine lithological and formational characteristics of base rocks, petrographical sampling was conducted from different rock units. To investigate the lithologic, mineralogical, and petrophysical properties of base rocks, petrographical thin sections comprising slices of rock samples 0.003 mm thick which have been fixed to glass microscope slides were prepared for microscopic studies. Formational and mineralogical analyses of these samples
Fig. 2. Micro photos; a) dacitic–andesitic lytic tuff, Op: opaque minerals, Pl: plagioclase, Gm: amorphous matrix and ironification in the matrix, (sample no. DA-3); b) dacitic– andesitic crystal tuff, Am: amphibole, Op: opaque minerals, Gm: glassy matrix (sample no. DA-1).
were performed with polarizing investigation microscope in Tunceli University and naming of the rocks was displayed. The unsanitary solid waste disposal site in the city of Tunceli is located at the area of Eocene volcanoclastics. A majority of the natural soil of the site is formed from hardened volcanic clasts. Field estimates of grain size and composition of the clasts were measured using the Fisher (1961) classification. Grain size between 2.00 and 0.063 mm was classified as volcanic lapillistone and smaller than 0.063 mm as volcanic tuff. Subsoil of the waste disposal site contains thick sequences of volcanic tuff and lapillistone. Closer to the surface, altered massive volcanic rocks (andesitic porphyry) were observed. Southeast of the site contains carbonates. The south side, covered mostly with solid waste, does not contain alluvium from the dried creek, but altered volcanic tuff and lapillistone. Volcanic tuff levels decrease toward the east and the creek mostly contains lapillistone. Pulumur River is comprised of sediments ranging from gravels to sands. At the North side of the waste disposal site, topsoil level is at a thickness ranging from 10 to 50 cm and at the South side from 20 to 60 cm topsoil. Lapillistones are the most abundant lithology of the site and tuff is second. Leveling is clearer at the direction of NE–SW and averages a 25° slope down to the SE. Four samples (DA-1 to DA-4) from tuff and eleven samples (DA-5 to DA-15) (Figure 1 and Table 1) from lapillistone and these volcanic rocks were analyzed with a polarizing microscope using thin sections and their mineralogical and petrographical properties were determined. In the tuff samples, the matrix micron-sized and amorphous, or glass-like. Tuff samples consisted of around 100 μm, small pieces of opaque minerals and plagioclase, and around ten micron sized
Fig. 3. Micro photos; a) andesitic lapillistone, Am: opacified amphiboles, Gm: glassy matrix, Pl: plagioclase (sample no. DA-8); b) dacitic lapillistone, Qtz: quartz, Pl: plagioclase, Gm: glassy matrix (sample no. DA-9).
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
Fig. 4. Altitude of sampling holes, depths of the holes and changes in natural soil with depth.
quartz and smaller sized amphibole microcrystals. Some plagioclase microcrystals display lamellar twinning and zoning. Carbonification and ironification in the matrix were observed. In these five samples, two samples were classified as dacitic–andesitic lytic tuff and three samples as dacitic–andesitic crystal tuff (Figure 2). Lapillistone samples consist of different sized subangular to rounded volcanic pebbles in a fine grained glassy matrix (Figure 3): mostly quartz, feldspar (plagioclase), and amphibole minerals together with dacitic, andesitic, and basaltic rock pieces. Dacitic rock pieces were composed of mainly plagioclase, sanidine, quartz, and less of amphibole and biotite; andesitic ones were composed of plagioclase and amphibole; and basaltic ones were composed of plagioclase, amphibole and less of pyroxene. Plagioclases contain not only large crystals but also microlites, generally having semi-euhedral forms, albite, and Carlsbad twins. Large crystals with stacking fractures, poecilitic textured with
79
amphibole microlites. Amphiboles show fissured fractures, either completely opacified hexagonal, or prismatic shaped or surrounded by an opacified rim on its edges. Hexagonal shaped ones display twin cleavage (Figure 3), and few crystals have clear green pleochroism. Ellipsoidal shaped andesitic rocks in lapillistones have similar mineralogical and textural properties with their lapillistone. They are formed mainly of plagioclases, sanidine, amphibole and relatively less of biotite and pyroxene. Plagioclases consisted of different grain sizes, distinctly shaped, twinned, zoned and highly altered and crushed. Sanidines, which are relatively less common at the site than plagioclases, are generally prismatic, distinctly shaped and Carlsbad twinned. Both amphiboles and biotites are generally distinct or semi-distinct shaped and completely opacified. Pyroxene displays opacification at its edges. In these rocks, opaque minerals are found either abundant as indistinct shapes in texture, or as an opacified texture, or as a formation of mafic pseudomorphic opaque minerals. In some places there are unaltered plagioclase inclusions in opacified amphibole crystal and in completely altered plagioclase phenocrystal. Groundmass of the rock also consists of feldspar, biotite and amphibole microlites. The phenocrystal rock's texture produced dense alteration and opacification. Andesites at the top level of volcaniclastic rocks show microlitic– porphyritic and vitroporphyritic texture. The main minerals are plagioclase, amphibole, quartz and relatively with less of prismatic biotite. Plagioclases exhibit highly crushed, faulted, concentric compositional zoning, albite polysynthetic twinning and subhedral and euhedral shaped medium grained crystals and porphyroblasts (Figure 3). Medium grain sized amphiboles are surrounded by an opacified envelope at the edges. Bigger grain sizes are opacified, prismatic shaped, generally crushed and mostly chloridized, surrounded by an opacified envelope. Bigger grain sizes are opacified, prismatic shaped, generally crushed and mostly chloridized. Quartz fine or medium grain size is crushed and in some places rounded. Biotites are of a smaller grain size than amphiboles. They are prismatic and embayed, mostly opacified completely. Groundmass of the rock consists of plagioclase, and amphibole microlites, interpenetrating quartz–plagioclase and uncrystallized glass materials. Subsoil of the site was altered and partially covered with topsoil. Six sampling holes were excavated to measure mineralogical composition and index properties of subsoil, and to determine the thickness of
Fig. 5. X-Ray Diffractometry (XRD) evaluation for six soil samples. A: Aerinite, B: biotite, C: calcite, D: dolomite, G: goethite, H: hematite, Hb: hornblende, O: opal, Ol: oligoclase, P: plagioclase, S: sanidine, Sm/A: smectite/aerinite, Q: quartz minerals.
80
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
Table 2 Percentage of grain size distribution of gravel, sand, silt and clay sizes and sample uniformity coefficient (Cu) and coefficients of curvature (Cc). Sample no.
Gravel
Sand
Silt
Clay
Cu
Cc
DZ-1 DZ-2 DZ-3 DZ-4 DZ-5 DZ-6
27.7% 12.6% 14.4% 3.4% 12.9% 31.4%
58.1% 65.5% 49.8% 32.3% 65.2% 60.5%
12.9% 20.68% 29.67% 50.9% 20.88% 7.5%
1.3% 1.22% 6.13% 13.4% 1.02% 0.7%
47.8 23.6 36.1 4.6 15.2 16.0
1.3 2.7 0.2 0.7 1.2 1.0
topsoil and altered zone. Tunceli's unsanitary solid waste disposal site's subsoil, surrounding area and valley in which waste leachate and seasonal surface water coming from the site flow consist of lapillistone and tuff. A couple centimeters to a couple decimeters of topsoil was observed on tuff, but no topsoil was observed on lapillistone at the northern edge of the valley. A small part of the site consists of tuff. The site and surrounding area are mostly lapillistone (Figure 4). XRD evaluation displayed that all samples of the natural soil have similar mineralogical composition (Figure 5). The mineralogical composition study for the sub-soil and rocks at the site showed that there is no inorganic pollutant with high solubility to pollute surface and groundwater. This study also showed that the subsoil of the site mostly does not contain minerals having a high absorption capacity. The subsoil of the site is mostly composed of silicate and carbonate minerals having low specific surface area, there is no or little presence of minerals having
large specific surface areas like smectite. The main components of this soil are plagioclase (feldspar) + quartz, clay and hornblende. In some samples, in addition to these minerals, zeolite, sanidine, dolomite + calcite + opal, hornblende, biotite, goethite and hematite were found. In all samples, clay minerals are Ca+2 rich smectite or aerinite (zeolite form) which is formed through hydrothermal processes. With the assumption of the natural soil's dacitic–andesitic composition not changing, it is normal to find plagioclase, quartz, and hornblende in all samples. Hornblende, biotite, oligoclase (plagioclase) and sanidine are derived from volcanic rocks. It is thought that iron oxide minerals such as hematite and goethite are derived from oxidation of volcanoclastic opaque minerals (most probably magnetite). Dolomite and calcite minerals might have formed with the reaction of carbonated ions carried by waters and Mg and Ca ions dissolved from hornblende which is an essential mineral of volcanoclastics. Smectites might have derived by alteration of plagioclases in volcanoclastics. Aerinite which is a zeolite mineral might have formed by hydrothermal alteration of basaltic–andesitic volcanoclastic or volcanites at the site and north of the site. In all samples large 14 Å picks are identified as clay minerals most probably Ca rich smectites. Other picks are other feldspar minerals, 3.34 Å picks are quartz minerals. These minerals were determined as essential minerals in the 3rd and 4th samples. Also, in all samples 3.22, 3.74, and 2.51 Å picks were observed and identified as sanidine minerals, and 4.02, 3.19 and 3.21 Å picks as oligoclase of plagioclases. In sample 1, oligoclases were the primary element, but in other samples
Fig. 6. Grain size distribution curves.
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
oligoclase was a secondary mineral. 1.77 and 1.80 Å picks, which are observed in samples 5 and 1, identified as quartz most likely pick cristobalite but other samples did not have these picks (Figure 5 and Table 1). Subsoil of the site is non-plastic in four samples (DZ-1, DZ-2, DZ-5, and DZ-6). DZ-3 and DZ-4 are plastic, so plastic limits and liquid limits were determined as 20.8, 37.08% (DZ-3) and 27.5, 45.37% (DZ-4) respectively. Plasticity index was calculated as 16.3 and 17.9 respectively. The subsoil's specific gravity varies between 2.45 and 2.70, and moisture content is between 3.9 and 18.2%. In Table 2, percentage of grain size distribution of gravel, sand, silt and clay sizes and sample uniformity coefficient (Cu) and coefficients of curvature (Cc) are displayed. Grain size distribution curves were displayed in Fig. 6. DZ1, DZ2, DZ-5 and DZ-6 natural soil samples are non-plastic — clay size grains are volumetrically less in amount. Subsoil particles
81
of samples DZ-1 and DZ-2 (north and northeast of the site) and samples DZ-5 and DZ-6 (southwest of the site) will disperse with contacting surface water, precipitation and waste leachate and increasing moisture content will carry easily through these suspended particles. These parts of the site are highly inclined; this also facilitates erosion and increases the amount of carried suspended particles. Generally natural soil in different parts of the site has similar characteristics. This easy erosion of the natural soil at the site may be understood as a decrease of the waste leachate pollution load in the subsoil of the site but since high silt, sand and low clay percentage in natural soil and based on XRD results, essential minerals of natural soil are feldspar and quartz, this leachate pollution load will not be adsorbed and pollution will be carried to the connecting environment. This will expand the area polluted from this disposal site. Subsoil sample results were also supported by visual observations at the site and surrounding environment in such a
Fig. 7. a) Erosion at the natural soil of the site. b) Polluted soil transport from natural soil of the site through leachate and seasonal precipitation to Pulumur River.
82
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
and November 2011, this leachate was absorbed by the soil and no other surface water emergence was observed.
Table 3 Permeability and classification of natural soil samples collected from the site. Subsoil samples
Subsoil classification based on USCS
Permeability (cm/s)
DZ-1 DZ-2 DZ-3 DZ-4 DZ-5 DZ-6
SM, poorly graded sand–silt mixture SM, poorly graded sand–silt mixture SC, poorly graded sand–clay mixture ML, low plastic silty or clayey fine sand SM, poorly graded sand–silt mixture SM, poorly graded sand–silt mixture
k20 °C k20 °C k20 °C k20 °C k20 °C k20 °C
= = = = = =
3.44 5.21 7.36 3.32 6.72 7.28
× × × × × ×
10−6 10−5 10−7 10−8 10−6 10−5
way that fine grain sized materials of topsoil are accumulated at Pulumur River (east of the disposal site). The pictures taken from the site show (Figure 7) erosion at the natural soil of the site and polluted soil transport from natural soil of the site through leachate and seasonal precipitation to Pulumur River. This indicates that pollution sourced from the site is carried through surface water and leachate to the surrounding environment. Subsoil classification and permeability values of the samples are displayed in Table 3. Except the south part of the site (DZ-3 and DZ-4, high clay percentage), other subsoil samples are classified as SM class according to USCS classification. Because of grain size and consistency properties, this class displays high liquefaction tendency, therefore subsoil of the site will not be stable, and it should not be forgotten that there is a possibility that disposed wastes could dislocate or collapse at this site. For subsoil of solid waste disposal sites, a second important factor is that, when the duration of water pressure exposed increases on the subsoil, there would be liquefaction potential, and there is a possibility that permeability could increase. Because of all these reasons, to keep subsoil of Tunceli's unsanitary solid waste disposal site stable, all waters coming from the surrounding environment to the site should be drawn away. Natural soil of the site is mostly non plastic, has no liquid limit, and is mostly SM class according to USCS classification. With precipitation or surface waters, moisture content of the soil increases and fast subsidence of ground may be observed. The rocks and subsoil at the site mostly do not contain minerals with high absorption capacity and low permeability to absorb the waste contamination and become natural barrier blocking or retarding the spread of pollutants to the groundwater. In most places of the site, permeability of the subsoil is more than required (10−8 cm/s). The values obtained from permeability tests of the site for subsoil samples vary from 10 −5 to 10−8 cm/s. Low permeability (10−7 and 10−8 cm/s) at the south part of the site increases to 10−5 cm/s at the subsoil of the North side. Extensively fractured and fissured volcanic sandstone levels at the side give potential to the waste leachate to reach deep levels in time. Therefore even after the site closed, with possibility of waste leachate existence, observational drilling should be conducted at the direction of rock slopes (Southeast). The map of the aquifer, seasonal variations in groundwater levels and chemical composition of groundwater should be studied to protect the aquifer. Considerable variation occurs in constituent concentrations of the leachates and this varies considerably from periods with dry and wet weathers (Johansen and Carlson, 1976). To compare the variation of the site's soil index properties and leachate concentration with annual precipitation, average annual precipitation was collected from official sources and determined as 659.7 mm between October 2010 and November 2011. But 73% of this precipitation occurs in four months between December and April. The leachates emerging from waste disposals and other surface waters (emerging from seasonal rains and groundwater) observed at the skirts of sliding areas of the site merge at the east part of the site (C1 and C2), flow zigzag around 1 km and reach to Pulumur River. It was observed that the highest discharge flow rate at this merged point reaches up to 3 l/s at the period between December 2010 and May 2011, but during the dry season between June
4. Conclusions The natural soil of the site and surrounding areas contain andesitic– dacitic volcanoclastic rocks formed by thick sequences of tuff and lapillistone. Tuff level is relatively less in amount, thin-medium bedded soft and altered, but volcanic sandstone level is more, medium-high thick bedded, good welded, faulted, fractured, and also very altered up to 1 m from the bottom of the site. Main minerals of the subsoil of the site consist of feldspar and quartz. Among these minerals, no mineral containing inorganic pollutant was determined. There is also no or little presence of environment friendly minerals like clay and zeolite which are seen abundantly in the volcanic terrains and having a high absorption capacity that can hold pollution of wastes. This also indicates that pollution at the site and surrounding environment is mainly due to this disposal site, and the subsoil of the site cannot hold this pollution. The leachate emerging from waste disposals combining with surface water (emerging from seasonal rains and groundwater) follows the path up to Pulumur River. This path contains extensively faulted, fissured, highly permeable (10−5 cm/s) volcanic sandstones. Therefore, highly contaminated leachate from the waste site has potential to reach groundwater sources. Geological investigation of the unsanitary solid waste disposal site of the municipality of Tunceli, Turkey displayed that the current site is not suitable for this purpose. Acknowledgments This study is funded by Tubitak (project no: CAYDAG-110Y019) and Tunceli University. Special thanks to the directors of these institutions for their support, and thanks to reviewers for their useful and constructive comments. References American Society for Testing and Materials (ASTM), 1998. Standard test method for laboratory determination of water (moisture) content of soil and rock by mass. Annual Book of ASTM Standards, D 2216. American Society for Testing and Materials (ASTM), 2000a. Standard test method for specific gravity of soil solids by water pycnometer. Annual Book of ASTM Standards, D 854. American Society for Testing and Materials (ASTM), 2000b. Standard test method for liquid limit, plastic limit, and plasticity index of soils. Annual Book of ASTM Standards, D 4318. Bruno, B., 2007. Hydro-geotechnical properties of hard rock tailing from metal mines and emerging geo-environmental disposal approaches. Canadian Geotechnical Journal 44 (9), 1019–1052. Chapius, R.P., 1990. Sand–bentonite liners: predicting permeability from laboratory tests. Canadian Geotechnical Journal 27, 47–57. Depountis, N., Koukis, G., Sabatakakis, N., 2009. Environmental problems associated with the development and operation of a lined and unlined landfill site: a case study demonstrating two landfill sites in Patra, Greece. Environmental Geology Journal, 56(7). Springer, pp. 1251–1258. Fisher, R.V., 1961. Proposed classification of volcaniclastic sediments and rocks. Geological Society of America Bulletin 72, 1409–1414. Johansen, O.J., Carlson, D.A., 1976. Characterization of sanitary landfill leachates. Water Research 10, 1129–1134. Kayabali, K., 1996. Engineering geological aspects of replacing a solid waste disposal site with a sanitary landfill. Engineering Geology 44, 203–212. Mondelli, G., Giacheti, H.L., Boscov, M.E.G., Elis, V.R., Hamada, J., 2007. Geoenvironmental site investigation using different techniques in a municipal solid waste disposal site in Brazil. Environmental Geology 52, 871–887. Nas, B., Cay, T., Iscan, F., Berktay, A., 2008. Selection of MSW landfill site for Konya, Turkey using GIS and multi-criteria evaluation. Environmental Monitoring and Assessment 160 (1–4), 491–500. Sener, S., Sener, E., Karaguzel, R., 2011. Solid waste disposal site selection with GIS and AHP methodology: a case study in Senirkent-Uluborlu (Isparta) Basin, Turkey. Environmental Monitoring and Assessment 173, 533–554. Simsek, C., Kincal, C., Gunduz, O., 2005. A solid waste disposal site selection procedure based on groundwater vulnerability mapping. Environmental Geology 49, 620–633. Wright, T.D., Ross, D.E., Tagawa, L., 1988. Hazardous-waste landfill construction: the state of the art. In: Freeman, Harry M. (Ed.), Standard Handbook of Hazardous Waste Treatment and Disposal. McGraw-Hill, Inc., New York, pp. 10.3–10.23.
Contents lists available at SciVerse ScienceDirect
Engineering Geology journal homepage: www.elsevier.com/locate/enggeo
Geo-environmental site investigation for Tunceli, Turkey municipal solid waste disposal site Ayten Öztüfekçi Önal a, 1, Deniz Demirbilek b, 1, Veysel Demir b,⁎ a b
Department of Geological Engineering, Tunceli University, Tunceli, Turkey Department of Environmental Engineering, Tunceli University, Tunceli, Turkey
a r t i c l e
i n f o
Article history: Received 8 August 2012 Received in revised form 12 March 2013 Accepted 18 March 2013 Available online 28 March 2013 Keywords: Solid waste Site investigation Unsanitary storage Environmental geotechnics
a b s t r a c t The environmental and geological condition of a current solid waste disposal site in the city of Tunceli, Turkey was investigated. Improper geological structure and soil properties of this unsanitary solid waste storage site as well as leachate from this site caused significant pollution in air, soil, and surface water. Natural soil characteristics and geology of the site are presented in this paper. Petrographic properties of vulcanized rubber rocks composed of tuff and volcanic sandstone at the bottom of storage sites and the mineralogical composition of the base composed of these rocks were examined. Permeability of the natural soil and index properties were determined using soil mechanics experiments (moisture content, specific gravity, Atterberg limit tests, sieve analysis, hydrometer analysis, falling-head permeability test, and standard proctor test) conducted on disturbed samples collected from excavated sites and the relationship between mineralogical composition and soil hydraulic behavior was investigated. Natural soil samples of six different parts of the site indicated that, the soil class in four samples is silty sands, sand–silt mixtures, one is clayey sands, sand–clay mixtures and one is clayey silts with slight plasticity. The values obtained using permeability tests for subsoil samples vary from 10−5 to 10−8 cm/s. Low permeability (10−7 and 10−8 cm/s) at the south part of the site increases to 10−5 cm/s at the natural soil of the North side. Extensively faulted and fissured volcanic sandstone levels at the site give potential to waste leachate to reach deep levels. The soil composition, hydraulic conductivity, topographic conditions, and other location criteria in the current solid waste disposal site showed that the current disposal site is not suitable for this purpose. © 2013 Elsevier B.V. All rights reserved.
1. Introduction Unsanitary solid disposal sites have been generally considered as an irregular solution of the waste disposal problem and most of them are used without sufficient geological, hydrogeological and environmental assessments. Environmental problems are expected to occur if no secure and environmental friendly measures associated with development are carried out (Bruno, 2007; Depountis et al., 2009). A significant source of natural soil, water, and air contamination can be caused from municipal and environmental waste disposal sites. There have been many studies conducted to prevent the pollution of the surface and groundwater from solid waste's leachate (Wright et al., 1988). Different geoenvironmental site investigation techniques can be applied to assess possible contamination from waste disposal sites (Mondelli et al., 2007). To minimize environmental risk factors, sanitary solid waste disposal sites are constructed after sufficient geological and environmental
⁎ Corresponding author. Tel.: +90 428 213 1794; fax: +90 428 213 1861. E-mail addresses: [email protected] (A. Öztüfekçi Önal), [email protected] (D. Demirbilek), [email protected] (V. Demir). 1 Tel.: +90 428 213 1794; fax: +90 428 213 1861. 0013-7952/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.enggeo.2013.03.014
assessments such as geotechnics of the site, hydrogeology, seismicity, etc. (Simsek et al., 2005; Sener et al., 2011). Open dumping is a common practice in Turkey. Around 67% of the generated municipal solid waste has been dumped at open dumps (Nas et al., 2008). Environmental problems caused by solid disposal such as odor problems, release of gases to atmosphere, risk of explosion or fire, uncontrolled leachate to surface and groundwater, and undesired visual pollution can easily be seen in these types of sites. In addition to these problems, even medical waste can be found in these sites. A site that is planned to become a sanitary landfill must initially be evaluated and assessed in details based on mineralogical and index properties of the subsoil and geological formations such as rock types, tectonic properties, the depth of groundwater level, etc. According to the solid waste control regulation of Turkey dated 1991 (14.3.1991-20814; amendment 05.04.2005-25777) the depth of the groundwater level must be at least 30–50 m and subsoil should have low permeability (10−8 m/s) thick clay segment or natural subsoil should have between 10 −6 and 10 −8 cm/s permeability (Chapius, 1990). An impermeable zone separating aquifer and subsoil of the site can block leaching process from the wastes. The current practice is to try hydraulical isolation of the waste in order to minimize the adverse effects of the disposal site on groundwater (Kayabali, 1996).
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
In the city of Tunceli, there is no sanitary solid waste disposal site. Currently all types of municipal wastes including medical waste have been deposited in an irregular way to the unsanitary solid disposal site. No environmental or geological assessments or any treatment of the site's natural soil was performed during selection of this site. The purpose of this study is to provide an assessment of current site's geology through a determination of the mineralogical composition and index properties of subsoil of the site, to indicate environmental risk factors and to draw attention to possible future environmental problems resulting from this site. To achieve these goals, the disposal site's geological map was created and samplings were performed to determine microscopic features of rock units and mineralogical composition of subsoil of the site. 2. Materials and methods Since some pollutants such as trace elements occur naturally in rocks and soils, the mineralogical composition of the sub-soil and rocks at the site was investigated to find out possible contaminant potential of the site's basin. This mineralogical composition study was also aimed to find out the content of minerals having high specific
77
surface value like clay minerals in subsoil of the site that can absorb the contaminants or became natural barrier blocking or retarding the spread of pollutants to the groundwater. To name rock units with microscopic analysis, fifteen volcanic rock samples were collected from solid waste sites and adjacent areas. To determine structural and mineralogical composition and index properties of natural soil of the site, six holes (C-1 to C-6) were excavated at six different points at the site as shown in Fig. 1. After the excavation, a piece of tarp was laid at the bottom of each hole and disturbed soil samples were taken with shaving soil from surface to the bottom of the hole. Samples were named from DZ-1 to DZ-6 (Table 1). To determine main minerals of cohesive subsoil of the site, the X-Ray Diffractometry (XRD) analysis of the DZ samples was constructed at Inonu University's (Malatya) Scientific Research Laboratory (IBTAM). The XRD resolves and microscopic studies of soil and volcanic rock samples were performed at Tunceli University Geology Department's Laboratory. Determination of specific gravity (ASTM D-854 (2000)), moisture content (ASTM D-2216 (1998) and TS 1900 (1997)), Atterberg plastic and liquid limits (ASTM D-4318 (2000) and TS 1900 (1997)), standard proctor test and sieve, hydrometer, and falling head permeability analysis (ASTM standard analysis) were completed.
Fig. 1. Geological map of the unsanitary solid disposal site and surrounding area at the city of Tunceli. from C-1 to C-6: prospect locations of sampling holes; DA: sampling locations of microscopic study.
78
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
Table 1 Mineral composition of natural soil of the site. Abbreviations are the same as those used in Fig. 5. Mineral composition Sample no. Coordinate
Sm/A P Q Hb O S
DZ-1 DZ-2 DZ-3 DZ-4 DZ-5 DZ-6
x x x x x x
39°6.850′N–39°36.266′E 39°6.843′N–39°36.250′E 39°6.754′N–39°36.290′E 39°6.763′N–39°36.374′E 39°6.744′N–39°36.498′E 39°6.746′N–39°36.371′E
x x x x x x
x x x x x x
x x x x x x
B H G D C
x x x x x x
x x
x x
x
x x
3. Results and discussion The solid waste disposal site in the city of Tunceli, Turkey and its surrounding areas' rock formations and other geological properties were investigated. A map showing the location of the municipal disposal site in Tunceli and the location of the studied transect is seen in Fig. 1. To determine lithological and formational characteristics of base rocks, petrographical sampling was conducted from different rock units. To investigate the lithologic, mineralogical, and petrophysical properties of base rocks, petrographical thin sections comprising slices of rock samples 0.003 mm thick which have been fixed to glass microscope slides were prepared for microscopic studies. Formational and mineralogical analyses of these samples
Fig. 2. Micro photos; a) dacitic–andesitic lytic tuff, Op: opaque minerals, Pl: plagioclase, Gm: amorphous matrix and ironification in the matrix, (sample no. DA-3); b) dacitic– andesitic crystal tuff, Am: amphibole, Op: opaque minerals, Gm: glassy matrix (sample no. DA-1).
were performed with polarizing investigation microscope in Tunceli University and naming of the rocks was displayed. The unsanitary solid waste disposal site in the city of Tunceli is located at the area of Eocene volcanoclastics. A majority of the natural soil of the site is formed from hardened volcanic clasts. Field estimates of grain size and composition of the clasts were measured using the Fisher (1961) classification. Grain size between 2.00 and 0.063 mm was classified as volcanic lapillistone and smaller than 0.063 mm as volcanic tuff. Subsoil of the waste disposal site contains thick sequences of volcanic tuff and lapillistone. Closer to the surface, altered massive volcanic rocks (andesitic porphyry) were observed. Southeast of the site contains carbonates. The south side, covered mostly with solid waste, does not contain alluvium from the dried creek, but altered volcanic tuff and lapillistone. Volcanic tuff levels decrease toward the east and the creek mostly contains lapillistone. Pulumur River is comprised of sediments ranging from gravels to sands. At the North side of the waste disposal site, topsoil level is at a thickness ranging from 10 to 50 cm and at the South side from 20 to 60 cm topsoil. Lapillistones are the most abundant lithology of the site and tuff is second. Leveling is clearer at the direction of NE–SW and averages a 25° slope down to the SE. Four samples (DA-1 to DA-4) from tuff and eleven samples (DA-5 to DA-15) (Figure 1 and Table 1) from lapillistone and these volcanic rocks were analyzed with a polarizing microscope using thin sections and their mineralogical and petrographical properties were determined. In the tuff samples, the matrix micron-sized and amorphous, or glass-like. Tuff samples consisted of around 100 μm, small pieces of opaque minerals and plagioclase, and around ten micron sized
Fig. 3. Micro photos; a) andesitic lapillistone, Am: opacified amphiboles, Gm: glassy matrix, Pl: plagioclase (sample no. DA-8); b) dacitic lapillistone, Qtz: quartz, Pl: plagioclase, Gm: glassy matrix (sample no. DA-9).
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
Fig. 4. Altitude of sampling holes, depths of the holes and changes in natural soil with depth.
quartz and smaller sized amphibole microcrystals. Some plagioclase microcrystals display lamellar twinning and zoning. Carbonification and ironification in the matrix were observed. In these five samples, two samples were classified as dacitic–andesitic lytic tuff and three samples as dacitic–andesitic crystal tuff (Figure 2). Lapillistone samples consist of different sized subangular to rounded volcanic pebbles in a fine grained glassy matrix (Figure 3): mostly quartz, feldspar (plagioclase), and amphibole minerals together with dacitic, andesitic, and basaltic rock pieces. Dacitic rock pieces were composed of mainly plagioclase, sanidine, quartz, and less of amphibole and biotite; andesitic ones were composed of plagioclase and amphibole; and basaltic ones were composed of plagioclase, amphibole and less of pyroxene. Plagioclases contain not only large crystals but also microlites, generally having semi-euhedral forms, albite, and Carlsbad twins. Large crystals with stacking fractures, poecilitic textured with
79
amphibole microlites. Amphiboles show fissured fractures, either completely opacified hexagonal, or prismatic shaped or surrounded by an opacified rim on its edges. Hexagonal shaped ones display twin cleavage (Figure 3), and few crystals have clear green pleochroism. Ellipsoidal shaped andesitic rocks in lapillistones have similar mineralogical and textural properties with their lapillistone. They are formed mainly of plagioclases, sanidine, amphibole and relatively less of biotite and pyroxene. Plagioclases consisted of different grain sizes, distinctly shaped, twinned, zoned and highly altered and crushed. Sanidines, which are relatively less common at the site than plagioclases, are generally prismatic, distinctly shaped and Carlsbad twinned. Both amphiboles and biotites are generally distinct or semi-distinct shaped and completely opacified. Pyroxene displays opacification at its edges. In these rocks, opaque minerals are found either abundant as indistinct shapes in texture, or as an opacified texture, or as a formation of mafic pseudomorphic opaque minerals. In some places there are unaltered plagioclase inclusions in opacified amphibole crystal and in completely altered plagioclase phenocrystal. Groundmass of the rock also consists of feldspar, biotite and amphibole microlites. The phenocrystal rock's texture produced dense alteration and opacification. Andesites at the top level of volcaniclastic rocks show microlitic– porphyritic and vitroporphyritic texture. The main minerals are plagioclase, amphibole, quartz and relatively with less of prismatic biotite. Plagioclases exhibit highly crushed, faulted, concentric compositional zoning, albite polysynthetic twinning and subhedral and euhedral shaped medium grained crystals and porphyroblasts (Figure 3). Medium grain sized amphiboles are surrounded by an opacified envelope at the edges. Bigger grain sizes are opacified, prismatic shaped, generally crushed and mostly chloridized, surrounded by an opacified envelope. Bigger grain sizes are opacified, prismatic shaped, generally crushed and mostly chloridized. Quartz fine or medium grain size is crushed and in some places rounded. Biotites are of a smaller grain size than amphiboles. They are prismatic and embayed, mostly opacified completely. Groundmass of the rock consists of plagioclase, and amphibole microlites, interpenetrating quartz–plagioclase and uncrystallized glass materials. Subsoil of the site was altered and partially covered with topsoil. Six sampling holes were excavated to measure mineralogical composition and index properties of subsoil, and to determine the thickness of
Fig. 5. X-Ray Diffractometry (XRD) evaluation for six soil samples. A: Aerinite, B: biotite, C: calcite, D: dolomite, G: goethite, H: hematite, Hb: hornblende, O: opal, Ol: oligoclase, P: plagioclase, S: sanidine, Sm/A: smectite/aerinite, Q: quartz minerals.
80
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
Table 2 Percentage of grain size distribution of gravel, sand, silt and clay sizes and sample uniformity coefficient (Cu) and coefficients of curvature (Cc). Sample no.
Gravel
Sand
Silt
Clay
Cu
Cc
DZ-1 DZ-2 DZ-3 DZ-4 DZ-5 DZ-6
27.7% 12.6% 14.4% 3.4% 12.9% 31.4%
58.1% 65.5% 49.8% 32.3% 65.2% 60.5%
12.9% 20.68% 29.67% 50.9% 20.88% 7.5%
1.3% 1.22% 6.13% 13.4% 1.02% 0.7%
47.8 23.6 36.1 4.6 15.2 16.0
1.3 2.7 0.2 0.7 1.2 1.0
topsoil and altered zone. Tunceli's unsanitary solid waste disposal site's subsoil, surrounding area and valley in which waste leachate and seasonal surface water coming from the site flow consist of lapillistone and tuff. A couple centimeters to a couple decimeters of topsoil was observed on tuff, but no topsoil was observed on lapillistone at the northern edge of the valley. A small part of the site consists of tuff. The site and surrounding area are mostly lapillistone (Figure 4). XRD evaluation displayed that all samples of the natural soil have similar mineralogical composition (Figure 5). The mineralogical composition study for the sub-soil and rocks at the site showed that there is no inorganic pollutant with high solubility to pollute surface and groundwater. This study also showed that the subsoil of the site mostly does not contain minerals having a high absorption capacity. The subsoil of the site is mostly composed of silicate and carbonate minerals having low specific surface area, there is no or little presence of minerals having
large specific surface areas like smectite. The main components of this soil are plagioclase (feldspar) + quartz, clay and hornblende. In some samples, in addition to these minerals, zeolite, sanidine, dolomite + calcite + opal, hornblende, biotite, goethite and hematite were found. In all samples, clay minerals are Ca+2 rich smectite or aerinite (zeolite form) which is formed through hydrothermal processes. With the assumption of the natural soil's dacitic–andesitic composition not changing, it is normal to find plagioclase, quartz, and hornblende in all samples. Hornblende, biotite, oligoclase (plagioclase) and sanidine are derived from volcanic rocks. It is thought that iron oxide minerals such as hematite and goethite are derived from oxidation of volcanoclastic opaque minerals (most probably magnetite). Dolomite and calcite minerals might have formed with the reaction of carbonated ions carried by waters and Mg and Ca ions dissolved from hornblende which is an essential mineral of volcanoclastics. Smectites might have derived by alteration of plagioclases in volcanoclastics. Aerinite which is a zeolite mineral might have formed by hydrothermal alteration of basaltic–andesitic volcanoclastic or volcanites at the site and north of the site. In all samples large 14 Å picks are identified as clay minerals most probably Ca rich smectites. Other picks are other feldspar minerals, 3.34 Å picks are quartz minerals. These minerals were determined as essential minerals in the 3rd and 4th samples. Also, in all samples 3.22, 3.74, and 2.51 Å picks were observed and identified as sanidine minerals, and 4.02, 3.19 and 3.21 Å picks as oligoclase of plagioclases. In sample 1, oligoclases were the primary element, but in other samples
Fig. 6. Grain size distribution curves.
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
oligoclase was a secondary mineral. 1.77 and 1.80 Å picks, which are observed in samples 5 and 1, identified as quartz most likely pick cristobalite but other samples did not have these picks (Figure 5 and Table 1). Subsoil of the site is non-plastic in four samples (DZ-1, DZ-2, DZ-5, and DZ-6). DZ-3 and DZ-4 are plastic, so plastic limits and liquid limits were determined as 20.8, 37.08% (DZ-3) and 27.5, 45.37% (DZ-4) respectively. Plasticity index was calculated as 16.3 and 17.9 respectively. The subsoil's specific gravity varies between 2.45 and 2.70, and moisture content is between 3.9 and 18.2%. In Table 2, percentage of grain size distribution of gravel, sand, silt and clay sizes and sample uniformity coefficient (Cu) and coefficients of curvature (Cc) are displayed. Grain size distribution curves were displayed in Fig. 6. DZ1, DZ2, DZ-5 and DZ-6 natural soil samples are non-plastic — clay size grains are volumetrically less in amount. Subsoil particles
81
of samples DZ-1 and DZ-2 (north and northeast of the site) and samples DZ-5 and DZ-6 (southwest of the site) will disperse with contacting surface water, precipitation and waste leachate and increasing moisture content will carry easily through these suspended particles. These parts of the site are highly inclined; this also facilitates erosion and increases the amount of carried suspended particles. Generally natural soil in different parts of the site has similar characteristics. This easy erosion of the natural soil at the site may be understood as a decrease of the waste leachate pollution load in the subsoil of the site but since high silt, sand and low clay percentage in natural soil and based on XRD results, essential minerals of natural soil are feldspar and quartz, this leachate pollution load will not be adsorbed and pollution will be carried to the connecting environment. This will expand the area polluted from this disposal site. Subsoil sample results were also supported by visual observations at the site and surrounding environment in such a
Fig. 7. a) Erosion at the natural soil of the site. b) Polluted soil transport from natural soil of the site through leachate and seasonal precipitation to Pulumur River.
82
A. Öztüfekçi Önal et al. / Engineering Geology 159 (2013) 76–82
and November 2011, this leachate was absorbed by the soil and no other surface water emergence was observed.
Table 3 Permeability and classification of natural soil samples collected from the site. Subsoil samples
Subsoil classification based on USCS
Permeability (cm/s)
DZ-1 DZ-2 DZ-3 DZ-4 DZ-5 DZ-6
SM, poorly graded sand–silt mixture SM, poorly graded sand–silt mixture SC, poorly graded sand–clay mixture ML, low plastic silty or clayey fine sand SM, poorly graded sand–silt mixture SM, poorly graded sand–silt mixture
k20 °C k20 °C k20 °C k20 °C k20 °C k20 °C
= = = = = =
3.44 5.21 7.36 3.32 6.72 7.28
× × × × × ×
10−6 10−5 10−7 10−8 10−6 10−5
way that fine grain sized materials of topsoil are accumulated at Pulumur River (east of the disposal site). The pictures taken from the site show (Figure 7) erosion at the natural soil of the site and polluted soil transport from natural soil of the site through leachate and seasonal precipitation to Pulumur River. This indicates that pollution sourced from the site is carried through surface water and leachate to the surrounding environment. Subsoil classification and permeability values of the samples are displayed in Table 3. Except the south part of the site (DZ-3 and DZ-4, high clay percentage), other subsoil samples are classified as SM class according to USCS classification. Because of grain size and consistency properties, this class displays high liquefaction tendency, therefore subsoil of the site will not be stable, and it should not be forgotten that there is a possibility that disposed wastes could dislocate or collapse at this site. For subsoil of solid waste disposal sites, a second important factor is that, when the duration of water pressure exposed increases on the subsoil, there would be liquefaction potential, and there is a possibility that permeability could increase. Because of all these reasons, to keep subsoil of Tunceli's unsanitary solid waste disposal site stable, all waters coming from the surrounding environment to the site should be drawn away. Natural soil of the site is mostly non plastic, has no liquid limit, and is mostly SM class according to USCS classification. With precipitation or surface waters, moisture content of the soil increases and fast subsidence of ground may be observed. The rocks and subsoil at the site mostly do not contain minerals with high absorption capacity and low permeability to absorb the waste contamination and become natural barrier blocking or retarding the spread of pollutants to the groundwater. In most places of the site, permeability of the subsoil is more than required (10−8 cm/s). The values obtained from permeability tests of the site for subsoil samples vary from 10 −5 to 10−8 cm/s. Low permeability (10−7 and 10−8 cm/s) at the south part of the site increases to 10−5 cm/s at the subsoil of the North side. Extensively fractured and fissured volcanic sandstone levels at the side give potential to the waste leachate to reach deep levels in time. Therefore even after the site closed, with possibility of waste leachate existence, observational drilling should be conducted at the direction of rock slopes (Southeast). The map of the aquifer, seasonal variations in groundwater levels and chemical composition of groundwater should be studied to protect the aquifer. Considerable variation occurs in constituent concentrations of the leachates and this varies considerably from periods with dry and wet weathers (Johansen and Carlson, 1976). To compare the variation of the site's soil index properties and leachate concentration with annual precipitation, average annual precipitation was collected from official sources and determined as 659.7 mm between October 2010 and November 2011. But 73% of this precipitation occurs in four months between December and April. The leachates emerging from waste disposals and other surface waters (emerging from seasonal rains and groundwater) observed at the skirts of sliding areas of the site merge at the east part of the site (C1 and C2), flow zigzag around 1 km and reach to Pulumur River. It was observed that the highest discharge flow rate at this merged point reaches up to 3 l/s at the period between December 2010 and May 2011, but during the dry season between June
4. Conclusions The natural soil of the site and surrounding areas contain andesitic– dacitic volcanoclastic rocks formed by thick sequences of tuff and lapillistone. Tuff level is relatively less in amount, thin-medium bedded soft and altered, but volcanic sandstone level is more, medium-high thick bedded, good welded, faulted, fractured, and also very altered up to 1 m from the bottom of the site. Main minerals of the subsoil of the site consist of feldspar and quartz. Among these minerals, no mineral containing inorganic pollutant was determined. There is also no or little presence of environment friendly minerals like clay and zeolite which are seen abundantly in the volcanic terrains and having a high absorption capacity that can hold pollution of wastes. This also indicates that pollution at the site and surrounding environment is mainly due to this disposal site, and the subsoil of the site cannot hold this pollution. The leachate emerging from waste disposals combining with surface water (emerging from seasonal rains and groundwater) follows the path up to Pulumur River. This path contains extensively faulted, fissured, highly permeable (10−5 cm/s) volcanic sandstones. Therefore, highly contaminated leachate from the waste site has potential to reach groundwater sources. Geological investigation of the unsanitary solid waste disposal site of the municipality of Tunceli, Turkey displayed that the current site is not suitable for this purpose. Acknowledgments This study is funded by Tubitak (project no: CAYDAG-110Y019) and Tunceli University. Special thanks to the directors of these institutions for their support, and thanks to reviewers for their useful and constructive comments. References American Society for Testing and Materials (ASTM), 1998. Standard test method for laboratory determination of water (moisture) content of soil and rock by mass. Annual Book of ASTM Standards, D 2216. American Society for Testing and Materials (ASTM), 2000a. Standard test method for specific gravity of soil solids by water pycnometer. Annual Book of ASTM Standards, D 854. American Society for Testing and Materials (ASTM), 2000b. Standard test method for liquid limit, plastic limit, and plasticity index of soils. Annual Book of ASTM Standards, D 4318. Bruno, B., 2007. Hydro-geotechnical properties of hard rock tailing from metal mines and emerging geo-environmental disposal approaches. Canadian Geotechnical Journal 44 (9), 1019–1052. Chapius, R.P., 1990. Sand–bentonite liners: predicting permeability from laboratory tests. Canadian Geotechnical Journal 27, 47–57. Depountis, N., Koukis, G., Sabatakakis, N., 2009. Environmental problems associated with the development and operation of a lined and unlined landfill site: a case study demonstrating two landfill sites in Patra, Greece. Environmental Geology Journal, 56(7). Springer, pp. 1251–1258. Fisher, R.V., 1961. Proposed classification of volcaniclastic sediments and rocks. Geological Society of America Bulletin 72, 1409–1414. Johansen, O.J., Carlson, D.A., 1976. Characterization of sanitary landfill leachates. Water Research 10, 1129–1134. Kayabali, K., 1996. Engineering geological aspects of replacing a solid waste disposal site with a sanitary landfill. Engineering Geology 44, 203–212. Mondelli, G., Giacheti, H.L., Boscov, M.E.G., Elis, V.R., Hamada, J., 2007. Geoenvironmental site investigation using different techniques in a municipal solid waste disposal site in Brazil. Environmental Geology 52, 871–887. Nas, B., Cay, T., Iscan, F., Berktay, A., 2008. Selection of MSW landfill site for Konya, Turkey using GIS and multi-criteria evaluation. Environmental Monitoring and Assessment 160 (1–4), 491–500. Sener, S., Sener, E., Karaguzel, R., 2011. Solid waste disposal site selection with GIS and AHP methodology: a case study in Senirkent-Uluborlu (Isparta) Basin, Turkey. Environmental Monitoring and Assessment 173, 533–554. Simsek, C., Kincal, C., Gunduz, O., 2005. A solid waste disposal site selection procedure based on groundwater vulnerability mapping. Environmental Geology 49, 620–633. Wright, T.D., Ross, D.E., Tagawa, L., 1988. Hazardous-waste landfill construction: the state of the art. In: Freeman, Harry M. (Ed.), Standard Handbook of Hazardous Waste Treatment and Disposal. McGraw-Hill, Inc., New York, pp. 10.3–10.23.