An investigation of heavy metal and migration through ... - Springer Link

Environ Monit Assess (2011) 176:87–98 DOI 10.1007/s10661-010-1568-3

An investigation of heavy metal and migration through groundwater from the landfill area of Eskisehir in Turkey Recep Bakis · Ahmet Tuncan

Received: 29 July 2009 / Accepted: 4 June 2010 / Published online: 18 June 2010 © Springer Science+Business Media B.V. 2010

Abstract This paper was conducted in order to determine the groundwater and soil pollution within and around the landfill of Eskisehir, Turkey. In this paper, mud, leachate and groundwater samples were collected seasonally a year from near Eskisehir landfill-site to investigate the possible impact of leachate which affects soil and groundwater quality. Concentrations of various heavy metals (Fe, Cu, Zn, Mn, Co, Pb, Cr, Ni and Mo) were determined in mud, leachate and groundwater samples. In addition, the heavy metal transportation infiltrated from landfill through a porous medium into the groundwater was modelled in order to determine the potential groundwater pollution caused by the leachate of the landfill. The modelling of the contaminant transportation was carried out by using a multiflow computer programme which simulates the distribution of heavy metal concentrations. As a result of this study, the distribution of the contaminant concentration was modelled and determined with respect to time and distance. Hence, the contaminant concentrations were determined at any time interval according to distance. The heavy metal contamination in groundwater does

R. Bakis (B) · A. Tuncan Civil Engineering Department, Anadolu University, Eskisehir, Turkey e-mail: [email protected]

not affect the wells found at far points from the source in a short time, e.g. 10, 20 and 30 days according to the obtained experimental results. When the time intervals extended more than 1 year, heavy metal concentrations decrease with distance but the concentration of the contamination increases when it gets closer to the pollution source. In this study, the potential contamination of groundwater was effectively estimated. Keywords Contamination transport · Groundwater · Heavy metal · Landfill · Soil pollution

Introduction The consumption of available resources has resulted in municipal solid waste (MSW) from industrial to domestic activities, which affect human health. Improper management of solid waste areas has resulted in serious ecological, environmental and health problems. Such practices contribute to widespread environmental pollution as well as spread of diseases. Health deterioration, accidents, flood occurrences and environmental pressures are a few of the negative effects of MSW. Other environmental effects include pollution of surface and subsurface waters, unpleasant odors, pest infestations and gas explosions. Municipal solid waste is a major

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environmental problem in Turkey and in many developing countries. The problem of solid waste management is an increasing issue in Turkey. Household solid waste generation is 1 kg day−1 per person in Eskisehir, also municipal solid waste generation is close to 1 kg day−1 where more than 25 million tons of municipal solid waste is ˙ 2008). generated every year in Turkey (TÜIK Most of the solid waste is illegally dumped in the MSW dumping areas. If the solid waste generated from industrial and agricultural activities are included, this amount increases to at least 40– 50 million tons per year in Turkey. Therefore, the management of solid waste, particularly MSW, has been one of the most important environmental issues of Turkey (Bakis et al. 1999). Municipalities are responsible from the domestic solid waste management including collection, transportation and final disposal according the Turkish constitution law. Solid wastes are generally dumped on the land without having any restrictions. In recent years, the situation of land filling has started to improve in some municipals by new valid laws called the Environmental Law 2872 (TME 2009) and related regulations of MSW which are conducted according to the standards. Solid waste disposal methods are a major public concern in Turkey. Majority of the municipal solid waste disposal sites are still open dumps. Only seven cities have regular sanitary landfills used to dispose municipal solid wastes and more than 12 landfills are in the construction stage. The same situation of MSW environmental problems exists in the Eskisehir landfill where MSW is still disposed in open dumps. It is known that the composition of leachate is more important than the physical composition of wastes in landfills (Ahmed and Sulaiman 2001; Critto et al. 2003). Leachate consists of a more complex mixture of organic and inorganic composition. The main source of leachate is liquid, which generally comes into existence during the organic dissolution in the landfill. The environment can be polluted by the leachates, which occurs at the end of decayed solid waste, mixed with precipitations of surface water. As a result, surface water collection system (rivers, creeks and lakes), subsurface collection system (groundwater reservoirs) and soil system (different soils layers) have

Environ Monit Assess (2011) 176:87–98

been seriously polluted by this leachate during transportation. Hence, landfills are one of the sources of groundwater and soil pollution due to the production of leachate and transportation of the contamination to the far points (Howard and Livingstone 2000; Islam and Singhal 2004; Slack et al. 2004; Von Der Heyden and New 2004; Kacaroglu and Gunay 1997). Furthermore, different hazardous gases of the landfill also pollute the atmosphere. Research site and sample locations This study was mainly conducted to determine the extent of groundwater and soil pollution within and around the landfill of the city of Eskisehir, Turkey. In this study, the Eskisehir landfill has been selected as a research site. Location of the Eskisehir dumping area is given in Fig. 1. Eskisehir city is located at northwest of interior Anatolia region. The population of the city is approx˙ 2008). Residents, imately 750,000 people (TÜIK businesses and institutions produced more than 250,000 tons of MSW per year which was generated from approximately 1 kg of waste per person per day in 2008. This quantity indicates that the rate of generated waste (in kilograms per person per day) and total waste generation (in million tons) have increased from 1960 to 2008. With these purposes, contaminated groundwater by waste disposal area in Eskisehir has been selected as a research site due to its adverse effect on the environment. The leachate samples have been taken to determine the amount of heavy metals in the area. This landfill, which contains a rather high concentration of contaminants, may pollute the rivers, lakes and aquifers in the Eskisehir region. Heavy metals may also seep and pollute the aquifers underneath the sites of disposal or agricultural usage. The solid waste produced from the Eskisehir landfill is then transported to the soil layer consists of conglomerate–sandstone, tuff–marl–clay and limestone, old and young alluvium disposal site according to the geological deposits (DSI˙ 2001). Thus, the amount of the toxic elements has to be known in order to take appropriate measurements to prevent groundwater contamination due to water flow through the fractures in formation.


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Fig. 1 Location of Eskisehir and research area

The groundwater level varies between 1 and 1.5 m below the surface. Average water level change was 1 m between dry and wet seasons. These problems are common to all disposal sites around the world.

Materials and methods Materials The samples have been collected in three categories such as mud, leachate and groundwater samples. They were taken every season for a year from the same sampling point. The para-

meters measured showed changes with respect to different seasons.

Mud samples The mud samples have been taken near the vicinity of landfill to determine the amount of heavy metals absorbed by the soil. Three leachate samples were seasonally taken to determine the heavy metal concentrations in summer and winter conditions. The mud samples were taken from soil fully contaminated by leachate and from 0 to 40 cm average depth of the layer near the edge of the landfill. Mud samples were stored in plastic bottles during transportation to the laboratory.

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Leachate samples The leachate samples have been taken near the vicinity of the landfill to determine the amount of heavy metals. Three leachate samples were seasonally taken to determine the heavy metal concentrations in summer and winter conditions. The liquid samples were collected from the surface leachate of the landfill area. Leachate samples were collected using lL polyethylene bottles that had been cleaned by soaking in 10% nitric acid and rinsed with distilled water, at the sampling site the bottles were rinsed twice with the water to be sampled prior to filling. The same procedure was carried out for groundwater sampling in the site. Groundwater samples The groundwater samples have been taken from a well, which was 600 m away from the landfill and whose depth was 3 m, to determine the amount of heavy metals. Three samples were seasonally taken to determine the heavy metal concentrations in summer and winter conditions. Groundwater also flows above the ground surface near this well during winter seasons.

Methods Mud samples were air dried for 3 days and oven dried at 105◦ C to constant weight for 24 h. Then these were disaggregated and sieved by using a 63-μm sieve after drying. Experiments were performed by using triplicate samples. A total of 1 g of the fine fraction was weighted and homogenized. Then each sample was digested using 750 ml/HCl and 250 ml/HNO3 called aqua regia at 115◦ C for 24 h (Novozamski et al. 1993). The

use of aqua regia is an internationally accepted analytical procedure and it is suitable for routine analysis of large series of soil samples (Muller et al. 1994; De Groot et al. 1982). The sample solutions were cooled and filtered by using Whatman no. 541 paper after acid digestion. The filtered solution was made up to 100 ml with distilled water. Mud samples were analyzed for Fe, Cu, Zn, Mn, Co, Pb, Cr, Ni and Mo metals by a flame atomic absorption spectrophotometer (AAS; Perkin Elmer Model 3110) using airacetylene flame with deuterium lamp background correction. Quantification of the metals was based on the calibration curves of standard solutions of respective metals. Experimental results are given in Table 1. According to Table 1, the concentrations of heavy metals in the mud samples taken in dry (summer) season are higher than the concentrations of wet (winter) season samples. According to the maximum heavy metal contents, the detection limits in mud samples were sequenced as Fe, Ni, Zn, Mn, Cu, Cr, Pb and Co. Heavy metal contents (mg kg−1 , dry weight) in mud samples exceeded the Turkish Standard of Control Regulation of Solid Wastes (CRSW) maximum tolerance limits in soil (mg kg−1 ; CRSW 2004). Among the metals in the landfill, iron was found to be the most abundant one with a concentration of 27,510 mg kg−1 . The results show relatively high contamination in the mud samples compared to the leachate samples. After sampling the leachate and groundwater, they were quickly transferred to the laboratory and stored in a cold room (4◦ C). The analysis was started without delay in the laboratory based on the priority to analyze parameters as prescribed

Table 1 Heavy metal concentrations in the mud samples taken from the Eskisehir landfill Type of the sample Name of standard

Collected Fe average depth of the samples

CRSW, max. – tolerance limits (mg kg−1 ) in soil Mud samples Summer 0–40 cm (mg kg−1 ) Winter 0–40 cm

Cu

Zn

Mn

Co

Pb

Cr

Ni

Mo

Fe has 100 300 800–1,000 50 100 100 50 10 different values 27,510 422 2,394 803 76.8 190 120.2 4,412.1 8.70 23,625 356 1,701 576 35.1 116 111.5 3,620 9.20

CRSW, Turkish Standard of Control Regulation of Solid Wastes, maximum tolerance limits in soil (mg kg−1 )


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Table 2 Heavy metal concentrations in the leachate samples taken from the Eskisehir landfill Type of sample

Leachate samples, average concentration on (mg L−1 ) a TSE

Standard name/seasons

Collected average depth

Fe

Cu

Zn

Mn

Co

Pb

Cr

Ni

Mo

According to the TSEa 266, max. tolerance limits (mg L−1 ) in water WHO standard health based guideline by the WHO, (mg L−1 ) Summer Winter

–

1.0

3.0

5.0

0.05

–

0.05

0.05

0.05

–

–

2.5

2.0

3

0.5

–

0.01

0.05

0.02

–

Surface Surface

4.580 2.610

0.120 0.100

0.270 0.180

0.100 0.080

0.134 0.110

0.350 0.150

1.110 1.050

0.320 0.270

0.045 0.039

266, Standard of Turkish drinking water (maximum tolerance limits in drinking water; mg L−1 )

by the Standard Methods for the Examination of Water and Wastewater (APHA AWWA 1992). For this purpose, samples were filtered through 0.45-μm Millipore filter paper. They were concentrated five times by the evaporation method for heavy metal analyses. To check the accuracy and precision of the measurements, (Merck) standard solutions with known concentrations were used. The analyses of heavy metal concentrations such as Fe, Cu, Zn, Mn, Co, Pb, Cr, Ni and Mo of the leachate and groundwater samples of the landfill have been determined using AAS for two

categories which are summer and winter samples. Experimental results are given in Tables 2 and 3, respectively. The concentrations of heavy metals such as iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), cobalt (Co), lead (Pb), chromium (Cr), nickel (Ni) and molybdenum (Mo) were determined in leachate and groundwater samples. The concentrations of these elements, in summer leachate samples, were 4.58, 0.12, 0.27, 0.10, 0.134, 0.35, 1.11, 0.32 and 0.045 mg L−1 , respectively. All the experiments were carried out in triplicate and the results are given in Table 2. Most

Table 3 Heavy metal concentrations in groundwater samples Type of the sample

Groundwater samples, (mg L−1 )

Standard name/seasons

Collected average depth

Fe

Cu

Zn

Mn

Co

Pb

Cr

Ni

Mo

According to the TSEa 266, max. tolerance limits (mg L−1 ) in water WHO standard health based guideline by the WHO, (mg L−1 ) Summer Winter

–

1.0

3.0

5.0

0.05

–

0.05

0.05

0.05

–

–

2.5

2.0

3

0.5

–

0.01

0.05

0.02

–

3m 3m

0.08 0.08

0.03 0.03

0.03 0.03

0.01 0.02

0.00 0.00

0.02 0.02

0.04 0.03

0.02 0.02

0.00 0.00

0.00 means no value detected according to detection limits of AAS a TSE 266, Standard of Turkish drinking water (maximum tolerance limits in drinking water; mg L−1 )

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of the heavy metal concentrations in the leachate samples exceed the limit values according to the Standards of Turkish drinking water (TSE 266) and World Health Organization (WHO) standards (TSE 266 1997; WHO 2009). Maximum detection limits of Fe, Pb, Cr and Ni were 4.58, 0.35, 1.11 and 0.32 mg L−1 , in the summer leachate sample, respectively. In the leachate samples, heavy metal concentrations such as Fe, Mn, Pb, Cr and Ni exceeded the limit values according to TSE 266 and WHO. The concentrations of heavy metals in groundwater such as iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), cobalt (Co), lead (Pb), chromium (Cr), nickel (Ni) and molybdenum (Mo) were determined. The average concentrations of these elements, in summer groundwater samples, were 0.08, 0.03, 0.03, 0.01, 0.00, 0.02, 0.04, 0.02 and 0.00 mg L−1 , respectively. All the experiments were carried out in triplicate and the results are given in Table 3. The results showed that the contamination in the leachate samples was relatively low compared to the mud samples. Heavy metal concentrations such as Fe, Cu, Zn, Co, Pb, Cr, Ni and Fe, Mn, Pb, Cr and Ni exceeded the limit values in the mud and leachate samples, according to TSE 266 and Turkish Standard of Waste Control Regulation. Groundwater concentrations did not exceed the limits given in the TSE 266 and WHO standards. Only Pb concentration exceeded the limit of WHO standard in groundwater samples.

Groundwater pollution Groundwater is being polluted by many contaminated sources such as leachate from municipal solid wastes, chemical liquid wastes in disposal sites, discharged spill of chemical or other waste materials, underground injection of unsuitable liquid wastes and placement of a septic tank systems in unsuitable location areas (Al-Tahani et al. 2004; Flyhammar 1997). All these pollutions result from human activities, population increase, industrial production and warped cities. Therefore, these contaminations contain different pollutants, for example heavy metals, organic matters,


phenol, sulphate, nitrate, nitrite, ammonia and manganese. So, firstly, it is required to determine the level of groundwater contamination for the modelling of the potential groundwater pollution. It is known that groundwater is polluted mainly by four sources, such as domestic, industrial, agricultural and natural (environmental). Each source can be classified due to its main origin (Bear and Verrujit 1987). Domestic contaminants are transported to the aquifer by the accidental breakage of pipelines, precipitation infiltrating through landfill or percolation from septic tanks. Industrial contaminants are transported to the aquifer by wastewater containing oils, grease, heavy metals, chemical compounds or accidents like the breakage of a pipeline. Agricultural contaminants are fertilizers, salts, pesticides and herbicides carried by irrigation water. Environmental pollution occurs from the intrusion of the precipitation that causes to dissolution of carbonate from the rocks to the groundwater. All relevant contaminants may be originated from the seepage of the polluted ponds and dam reservoirs, leachate of landfills, the liquid waste in underground pits, the leakage of septic tanks and irrigated lands. Generally, it is accepted that Darcy’s law is valid for groundwater flow (Bear 1972; Freeze and Cherry 1979; Fired 1975). Darcy’s law can be defined as the relationship between the properties of the porous medium and the hydraulic gradient. The environment is saturated and the groundwater is in steady-state flow according to this law. On the other hand, contaminant is approximately continuous and it can be assumed that the transporting process occurs in homogenous soil layers and isotropic porous media. In this study, the mathematical modelling of contaminant transportation in a porous medium is carried out to determine the potential groundwater pollution of the Eskisehir landfill. The distribution of the pollutant concentrations was found with the mathematical model and the results were obtained graphically. In order to determine the concentration distribution with respect to time and distance, as well as the thickness of the aquifer, the velocity of groundwater and the dispersivity of the contamination; a multiflow computer programme developed by Walton (1989)


was used (Tombul and Koparal 2003; Bakis et al. 1999; Lee 1988; Wilsion and Miller 1978). The modelling of heavy metal transportation in groundwater Estimation of the boundary and initial conditions of the contaminant transport as well as the scaling of parameters is an uncertain process according to Lee (1988). The influence of pollution to groundwater takes place as water leaks from small point, infiltrates in a cracked path and polluting sources reach the groundwater. The influence of contamination depends on its initial concentration, distance to the groundwater and the flow velocity. The pollutant transport can be in the vertical direction until reaching to groundwater due to gravitational acceleration because the contamination transport depends on water flow. However, the movement of water could be either vertical or horizontal depending on the flow characteristics and the availability of the hydrogeological structure. It was stated by Bear (1972) that the governing mechanisms of the contaminant transport in a fluid was hydrodynamic dispersion, where the solution is dispersed by the need of the liquid which flows around the solid soil particles (Bear 1972). This system is the solution of the classical advection–dispersion equation describing the contaminant transport at any point according to Hunt (1983). Determining the pollutant movement depends on a certain number of parameters such as a porous and piezometric surface. Direct explanation of the model of contaminant transport has also been made. On the other hand, when the groundwater flow becomes two dimensional, the polluted area can be three dimensional (Lee 1988). Seeps from the waste landfill pollute the aquifer with heavy metals, salts, etc. It is considered that free surface of the Eskisehir landfill is expected to pollute the aquifer with high concentrations of pollutants. The pollution occurring from the leakage of contaminant sources can influence the aquifer by movement in both vertical and horizontal directions and mixing with the groundwater flow system. Contaminant transportation by groundwater should be accurately

93

estimated to determine the total potential of the pollution. Real estimation can be done by modelling according to the spreading and transporting of contamination in complicated aquifer groundwater. In this research area, groundwater below the landfill site has been intensively polluted by iron (Fe) and chromium (Cr). Only these two elements in leachate samples are used for the simulation given in Table 2. This pollution has been accepted as a permanent source and the dispersion of the contaminant concentration with respect to time and distance was simulated by the multiflow programme. The effects of pollution parameters on the wells which provide drinking and domestic water have been simulated. This research was done by using some hypothetical data, which represent alluvion aquifer characteristics of the Eskisehir groundwater. The averages of aquifer characteristics of the Eskisehir groundwater have been used and their values are given in Table 4.

Model description The following assumptions were made to idealize the aquifer conditions. The results were obtained by using contamination values, and the layer thickness of the aquifer. The assumptions

Table 4 The required data for application of the Multiflow programme Parameter

Value

Number of grids in x–y direction Grid space (m) The length of x–y simulation region (m) The porosity of aquifer in the region Effective porosity The thickness of aquifer (m) Longitudinal dispersivity (m), D1 Transverse dispersivity (m), Dt The number of contaminant sources The number of contaminant point sources The x–y coordinates of contaminant sources The amount of infiltration from contaminant sources (L day−1 ) The initial concentration of contaminant in source (mg L−1 )

20 × 20 30 600–600 0.25 0.25 20 10 1 1 1 0–360 36,000 Fe = 4.580

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mentioned below do not cause any important errors in the model: • • • • • • •

The porous environment is homogenous, isotropic and saturated Flow velocity of the groundwater is uniform and in one direction Movement in horizontal direction is much greater than in vertical direction The movement is two dimensional (vertical and horizontal) The movement of pollutants in the groundwater is the same as the flow of groundwater Density and viscosity differences between the contaminant and the groundwater have been ignored The properties of the dispersion for a certain time and distance are unchanged

There are many analytical equations for the mathematical modelling of contaminant transport (Hunt 1983; Bear and Verrujit 1987; Kinzelbach 1986). Generally, the assumptions mentioned above may not have relations with mass transport. The interactions of the mixture at a certain distance from a point of source depends on its speed, constant vertical dispersion and the thickness of the aquifer (Kinzelbach 1986; Tombul and Koparal 2003). The contaminants can mix with groundwater and their transportation in a porous medium can be calculated by an advection dispersion equation (Freeze and Cherry 1979). This may also be calculated by a hydrodynamic spread and the analytical solution of Eq. 1, given below. D

∂C ∂ 2C −v + 2 ∂x ∂x

ρb ∂s × n ∂t

+

∂C ∂t

= rm

terms represent dispersion and advection, respectively. The third and fourth terms represent adsorption and chemical biological deterioration, respectively. It is assumed that adsorption and

a

b

∂C ∂t (1)

Where D is the coefficient of dispersion (m2 day−1 ), v is the average flow velocity, ρ b is the density of formation (g cm−3 ), C is the contaminant concentration (mg L−1 ), s is the absorption mass per unit weight of rock (g g−1 ), n is the porosity, t is time and rm is chemical reaction and biological deterioration. On the left part of Eq. 1, the first and second

c Fig. 2 Expected concentration values and distribution of Fe pollution toward drinking well after 10, 100 and 1,000 days in a, b and c, respectively. a Concentartion distribution of Fe (mg L−1 ) after 10 days. b Concentartion distribution of Fe (mg L−1 ) after 100 days. c Concentartion distribution of Fe (mg L−1 ) after 1,000 days


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chemical biological deterioration terms are being neglected. Thus, Eq. 1 can be written as ∂ 2C D1 2 + Dt ∂x

∂ 2C ∂ 2C + ∂ y2 ∂z2

−v

∂C ∂C = ∂x ∂t

C is the contaminant distribution in the aquifer, x is the direction, B is the Huntush leakage factor, m is the thickness of the aquifer layer, r is a function of contaminant distance from a point source, α 1 is the longitudinal dispersivity coefficient, α t is the transverse dispersivity coefficient, u is a dimensionless parameter for the hydraulic of the well and W is a well function represent by W (u, r/B) and found by Walton (1989): r W u, B

r (r/B) − 2u B = π exp − erfc − (5) √ 2r B 2u

(2)

Where D1 is the longitudinal dispersion coefficient, Dt is the transverse dispersion coefficient. These dispersion coefficients are important to solve Eq. 2. These are a function of soil characteristics and change with respect to the influence of aquifer, i.e. flow velocity, and they are obtained from the land or laboratory tests. This is done by the experimental scale measurement and from the analytical solution of Eq. 2, which gives the concentration of contaminant distribution depending on time and distance in one dimension. The solution of this equation for the case where the contaminant feeds the source Q and the concentration is continuously infiltrated (injected) into the aquifer was given by Hunt (1978). If the equation of two dimensions does not contain adsorption and radioactive deterioration, it can be expressed as below (Fired 1975; Wilsion and Miller 1978): C=

r C0 Q exp (x/B) .W u, √ 4 × 10−3 × π nvt α1 αt B

Application of the model The concentrations of heavy metals for different time periods were determined by considering the contamination as a continuous source of point with a constant infiltration value of 35,000 L day−1 (0.405 L s−1 ), which is mixed into the aquifer from landfill. The contaminant transport simulation in groundwater was carried out with the Multiflow programme developed by Walton (1989) in order to determine how long the potential of heavy metal contamination is distributed which depends on time vs. distance, velocity of groundwater flow, porous medium and soil structure. The municipal solid wastes of Eskisehir have been damped in a valley located far from 15 km distance from the city centre since 1960. The slope of this valley is nearly 10%. Due to the characteristic of the soil structure, contaminated water seeps into the underground in the same region. Well parameters associated with the aquifer layer,

(3)

This solution gives the thickness of the unit aquifer. If Eq. 3 is divided by the thickness of the aquifer, Eq. 4, given below, can be obtained: C=

r 7.957×10−5 ×C0 Q exp (x/B) .W u, √ mvt α1 αt B

Where u =

r2 , 4α1 vt

(4)

r = x2 + y2 ( αα1t vv ) and b = 2α1

Table 5 Variation of model and distribution of heavy metal concentrations (Fe, Cr) with time and distance Heavy metal Fe

Cr

Days

10 100 1,000 10 100 1,000

Seepage, Q(L day−1 ) 36,000 36,000 36,000 36,000 36,000 36,000

Initial concentration

Aquifer thickness

Dispersivity (m)

C0 (mg L−1 )

(m)

D1

Dt

4.58 4.58 4.58 1.11 1.11 1.11

20 20 20 20 20 20

10 10 10 10 10 10

1 1 1 1 1 1

Velocity (m day−1 )

Concentration at desired point C (mg L−1 )

1 1 1 1 1 1

0 0 0.09 0 0 0.05

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which carries the groundwater around the landfill, have been used for the above model. These parameters are considered to have the following values: The thickness of the saturated aquifer is 20 m, in which the hydraulic gradient is 0.0667, the hydraulic conductivity is 3.47 × 10−6 cm s−1 or 29.9885 m day−1 and the groundwater flow speed is 1 m day−1 . The other values are given in Table 4 by taking the porosity of the aquifer as 0.25.

a

The heavy metals with the highest concentrations have been found as iron (Fe) and chromium (Cr) in the summer leachate samples (Table 2). So, the simulation of the model was carried out only with these two heavy metals in the leachate samples. In the landfill, the initial iron concentration was 4.580 mg L−1 , which is the highest value in the leachate of the summer season as shown in Table 2. The total Fe concentration did not reach to the observation well after 10 days and 100 days as shown in Fig. 2a and b, respectively. However, the concentration of Fe reached to 0.09 mg L−1 after 1000 days as shown in Fig. 2c. The same simulation was made for the Cr concentration and all of the results are given in Table 5, which contain the variation of the model and heavy metal distribution of time-dependent concentration. The same simulations were carried out for the determination of the distribution of Cr concentrations using the Multiflow programme. The resulting graphs are given in Fig. 3a, b and c, respectively.

Conclusions

b

c Fig. 3 Expected concentration values and distribution of Cr pollution toward drinking well after 10, 100 and 1,000 days in a, b and c, respectively. a Concentration distribution of Cr (mg L−1 ) after 10 days. b Concentration distribution of Cr (mg L−1 ) after 100 days. c Concentration distribution of Cr (mg L−1 ) after 1,000 days

In this paper, mud, leachate and groundwater samples were collected seasonally a year from near Eskisehir landfill-site and the concentrations of various heavy metals (Fe, Cu, Zn, Mn, Co, Pb, Cr, Ni and Mo) were determined in mud, leachate and groundwater samples. The highest heavy metal concentrations were found in the mud samples for summer and winter seasons. According to the maximum heavy metal contents, heavy metal concentrations in the mud samples exceeded the Turkish Standard of Control Regulation of Solid Wastes maximum tolerance limits in soil (mg kg−1 ). The results showed relatively high contamination in the mud samples compared to the leachate samples. Also, heavy metal concentrations in the leachate samples exceeded the limit values of the TSE266 and WHO standards. Groundwater heavy metal concentrations did not exceed the limits given in the TSE 266 and WHO standards. Only the Pb concentration exceeded the limit of the WHO standard in the groundwater samples.


In addition, the modelling of the heavy metal transportation, infiltrated from landfill through a porous medium into the groundwater, has been investigated. The modelling of the contaminant transportation was carried out by using a Multiflow computer programme which simulates the distribution of heavy metal concentrations. As a result of this study, it was seen that the heavy metal contamination in groundwater does not affect the wells found at far points from the source in a short time, e.g. 10, 20 and 30 days according to the obtained experimental results. When the time intervals extend more than 1 year, heavy metal concentrations decrease with distance but the concentration of the contamination increases when it gets closer to the pollution source. In conclusion, the concentrations of the Fe and Cr metals obtained from the simulation model at the end of 1,000 days are approximately close to the concentrations obtained experimentally from the observed groundwater well. Therefore, from these data, the distribution of heavy metal contamination can be forecasted using the model for the future evaluation of heavy metal concentrations. This simulation model can be used for the planning and management of well observation and the prevention of contamination distribution in groundwater. Acknowledgements The authors would like to thank to the director of Soil Research Institute of Eskisehir where the total heavy metal concentrations in groundwater, leachate and mud samples were determined by using Perkin Elmer Atomic Absorption Spectrometer 3110.

References Ahmed, A. M., & Sulaiman, W. N. (2001). Evaluation of groundwater and soil pollution in a landfill area using electrical resistivity imaging survey. Environmental Management, 28(5), 655–663. Al-Tahani, A. A., Beaven, R. P., & White, J. K. (2004). Modelling flow to leachate wells in landfills. Waste Management, 24, 271–276. APHA, AWWA (1992). Standard methods for the examination of water and wastewater (18 ed.). Washington: American Public Health Association/American Water Works Association. Bakis, R., Tombul, M., & Bilgin, M. (1999). Simulation of heavy metal contaminant of which leachate and pollu-

97 tion diffusions groundwater with Multiflow Software. In The symposium of city management, human and environmental problems, proceeding books (Vol. III, pp. 433–442). Istanbul, Turkey. Bear, J. (1972). Dynamic of f luid in porous. New York: American Elsevier. Bear, J., & Verrujit, A. (1987). Modelling groundwater f low and pollution. Dordrecht: D. Reidel. CRSW (2004). Turkish Standard of Solid wastes Control Regulation. T.R. Ministry of the Environment and Forestry. Critto, A., Carlon, C., & Marcomini, A. (2003). Characterization of contaminated soil and groundwater surrounding an illegal landfill (S. Giuliano, Venice, Italy) by principal component analysis and kriging. Environnemental Pollution, 122, 235–244. De Groot, A. J., Zschuppe, K. H., & Salomonas, W. (1982). Standardization of methods of analysis for heavy metals in sediments. Hydrobiologia, 92, 689– 695. DSI˙ (2001). The planning of water resources of Porsuk Basin, Final report, volume 1/3, General Directorate ˙ III. Regional Direcof State Hydraulic Works (DSI), torate, Carried out by Su Yapı Consultant and Engineering, Eskisehir, Turkey. Fired, J. J. (1975). Groundwater pollution (p. 330). Amsterdam: Elsevier Scientific. Flyhammar, P. (1997). Estimation of heavy metal transformation in municipal solid waste. The Science of the Total Environment, 198, 123–133. Freeze, R. A., & Cherry, J. A. (1979). Groundwater. Englewood Cliffs: Prentice-Hall Inc. Howard, K. W. F., & Livingstone, S. (2000). Transport of urban contaminations into Lake Ontario via subsurface. Urban Water, 2, 183–195. Hunt, B. (1978). Dispersive sources in uniform groundwater flow. Journal of Hydrology Division, 104, 75–85. Hunt, B. (1983). Mathematical analysis of groundwater resources. Butterworth & Co., Ltd. Islam, J., & Singhal, N. (2004). A laboratory study of landfill–leachate transport in soils. Water Research, 38, 2035–2042. Kacaroglu, F., & Gunay, G. (1997). Groundwater nitrate pollution in an alluvium aquifer, Eskisehir urban area and its vicinity, Turkey. Environmental Geology, 31(3/4), 178–184. Kinzelbach, W. (1986). Groundwater modelling and introduction with sample programs in basic. Amsterdam: Elsevier Science. Lee, C. (1988). Groundwater contaminant transport. PhD thesis, University of Prude, West Lafayette, IN, USA. Muller, H. W., Schwaighofer, B., & Kalman, W. (1994). Heavy metal contents in river sediments. Water Air, Soil Pollution, 72, 191–203. Novozamski, I., Lexman, T. M., Houba, V. J. G. (1993). A single extraction procedure of soil for evaluation of uptake of some heavy metal by plants. International Journal of Environmental Analytical Chemistry, 51, 47–58. Slack, R. J.,Gronow, J. R., & Voulvoulis, N. (2004). Household hazardous waste in municipal landfill:

98 Contaminations in leachate. Science of the Total Environment, 37(1–3), 119–137. TME (2009). Turkey’s the Ministry of Environment (TME), Environmental Law 2872. Tombul, M., & Koparal, A. S. (2003). The mathematical modelling of total nitrogen contamination transport via groundwater from a sugar factory in Eskisehir, Turkey. International Journal of Environment and Pollution, 19(2), 188–196. TSE 266 (1997) Turkish Drinking Water Standard (p. 96) (in Turkish). ˙ (2008) Republic of Turkey, Prime Ministry of State TÜIK Institute of Statistics. http://www.die.gov.tr.

Environ Monit Assess (2011) 176:87–98 Von Der Heyden, C. J., & New, M. G. (2004). Groundwater pollution on the Zambian copper belt: Deciphering the source and the risk. Science of the Total Environment, 327, 17–30. Walton, W. C. (1989). Analytical groundwater modelling (p. 173). Clinton: Lewis. WHO, The World Health Organization (WHO) (2009). Drinking water Standard. http://www.who.int/water_ sanitation_health/dwq/guidelines/en/index.html. Accessed 25 July 2009. Wilsion, J. L., & Miller, P. J. (1978). Two dimensional plume uniform groundwater flow. Journal of Hydrology Division American of Engineering, HY4, 503–514.