Original article
Influences of human activities and
agriculture on groundwater quality
of Kayseri-Incesu-Dokuzpınar
springs, central Anatolian part
of Turkey
Hatim Elhatip Æ Mustafa Afşin Æ llkay Kuşçu Æ Kadir Dirik
Yakup Kurmaç Æ Murat Kavurmacı
Abstract Human activities and agriculture have had
direct and indirect effects on the rates of contamination of groundwater in the Incesu-Dokuzpınar
spring area. Direct effects include dissolution and
transport of excess quantities of fertilizers with
associated materials and hydrological alterations
related to irrigation and drainage. Indirect effects may
include changes in water–rock reactions in soils and
aquifers caused by increased concentrations of
dissolved oxidants, protons, and major ions.
Agricultural activities have directly or indirectly
affected the concentrations of a large number of
inorganic chemicals in groundwater, for example
NO3, N2, Cl, SO42, H+, K, Mg, Ca, Fe, Cu, B, Pb, and Zn,
as well as a wide variety of pesticides and other
organic compounds. For reactive contaminants like
NO3, it is recommended that a combination of
hydrochemical and environmental-tracer analytical
approaches might be required to resolve changing
inputs from subsequent alterations as causes of
concentration gradients in groundwater. The water
type of Dokuzpınar springs is mainly Na–Mg–Ca–Cl–
HCO3. Note that the water types of the springs were
directly related to the hydrogeochemical properties of
outcrops at the study area. Thus, the high concentration of Ca2+ and HCO3 is mainly related to the
high CO2 contents in the marbles, whereas the high
Na concentration arises from the existing syenite,
volcanic ash, basalt, and clay units, although the
I_ ncesu-Dokuzpınar springs cover most of the
drinking and irrigation water demands of this area.
The high concentrations of NO3 and NaCl show that
the area around the springs is continuously being
contaminated by untreated sewage and agricultural
wastes, especially during dry periods. Therefore, this
approach is based on the vulnerability studies of the
catchment area, determination of the transfer time
of the pollutant, and the water-bearing formations of
I_ ncesu-Dokuzpınar springs. Vulnerability in this
study is defined as the intrinsic hydrogeochemical
characteristics of an aquifer, which may show the
sensitivity of groundwater to be contaminated by
different human activities.
Keywords Dokuzpınar Springs Æ Human activities Æ
Agriculture Æ Contamination Æ Turkey
Introduction and objectives
Received: 7 October 2002 / Accepted: 28 January 2003
Published online: 10 April 2003
ª Springer-Verlag 2003
H. Elhatip (&) Æ Y. Kurmaç
Aksaray Engineering Faculty, Environmental Eng. Dept.,
Niğde University, 68100 Aksaray, Turkey
E-mail: [email protected]
Tel.: +90-382-2150953
Fax: +90-382-2150592
M. Afşin Æ l. Kuşçu Æ M. Kavurmacı
Aksaray Engineering Faculty, Geological Eng. Dept.,
Niğde University, 68100 Aksaray, Turkey
K. Dirik
Faculty of Engineering, Geological Eng. Dept.,
Hacettepe University, 06532 Ankara, Turkey
490
Environmental Geology (2003) 44:490–494
I_ ncesu is a province of Kayseri City in the central Anatolian part of Turkey (Fig. 1). The study area lies between
latitudes 3830¢ and 3900¢ and longitudes 3500¢ and
3636¢. Kayseri-I_ ncesu has a wet climate with cold and
heavy rain in winter and hot summers. The research area
comprises different volcanic rocks from Paleocene to
Paleo-Quaternary age that have been highly effected by a
series of fault zones and reflects different hydrogeological
characteristics. Occurrence of springs in the project area
is mainly related to tectonism and Erciyes volcanism. The
I_ ncesu-Dokuzpınar springs (I_ DSp) emerge from basalt
rocks. The whole area of the springs is covered by volcano-sedimentary rocks. Note that the previously mentioned waters discharge upwards along fault lines after
leaching the pervious water-bearing formations (Fig. 2).
DOI 10.1007/s00254-003-0787-0
Original article
Fig. 1
Location map of the study area
The main objectives of this study are: to evaluate the influences of human activities and agriculture on groundwater
quality of Kayseri-Incesu-Dokuzpınar springs, to utilize the
hydrogeochemistry of the main aquifer that recharges the
springs, and to evaluate the factors that control the rate and
sources of pollutant hazards in the study area. A general
view of the springs is given in Fig. 3. The degradation of
groundwater depends on the pollution load and the behavior of pollutants as well as the geological and hydrogeochemical factors that control the flow and dispersion. The
evaluation of these factors in the most populated areas
around Kayseri-I_ ncesu is the subject of the present work.
Knowledge of the susceptibility of groundwater to pollution
is important to identify remedies and establish the water
quality and environmental protection according to TSE
(Turkish Standard Institute 1997). Man’s use and reuse of
water for domestic, industrial, and agricultural purposes in
the overpopulated regions result in the discharge of liquid or
solid wastes with different kinds of contaminants into the
geological environment. As a result, groundwater quality is
seriously stressed.
Hydrogeochemistry of the springs
Results of the hydrochemical analysis is given in
Table 1. The main water type of I_ ncesu-Dokuzpınar
springs is Na–Mg–Ca–Cl–HCO3. The water type of the
springs was directly related to the hydrogeochemical
properties of outcrops at the study area. Thus, the high
Na concentration arises from the existing syenite, volcanic ash, basalt, and clay units that exist in the study
area. The Ca/Mg, Ca/Na and SO4/Cl ratios, and base
change index decrease from the recharge area downwards to the discharge area. This reduction showed that
the duration of water-rock contact, depth of groundwater flow pattern, and the travel time increased
(Appelo and Postma 1992).
The periodic variation in temperature, pH and electrical
conductivity (EC) values, and concentrations of individual ions in the water samples from the study area, are
graphically illustrated in Fig. 4. A periodic general uniformity in chemical composition exists, which is related
to conditions of sources and rate of recharge at the outlet
points of the I_ ncesu-Dokuzpınar springs. The general
changes in the EC values of groundwater from the spring
area are periodically compared with the higher ion concentration changes during the dry and wet seasons. At
the end of the dry periods (October), addition of salts
may lead to an increase in EC and NaCl values and may
cause chemical reactions between the Na and Ca ions
during ion exchanges. Also, the high concentrations of
most ions in the groundwater probably result from surface leaching during irrigation and from contamination
by sewage.
Environmental Geology (2003) 44:490–494
491
Original article
Fig. 2
Geological map of the study area and its vicinity
Fig. 3
General view of the I_ ncesu-Dokuzpınar springs
492
Environmental Geology (2003) 44:490–494
Influence of human activities
and agricultural contaminants
on water quality
The phrase ‘‘agricultural contaminants’’ in this study refers to chemicals whose concentrations in groundwater
seem to be higher than they would be in the absence of
agricultural activities, although they might not necessarily
come directly from applied artificial substances. Use of the
word ‘‘contamination’’ is meant to imply that human activities have caused an increase in the flux or concentration of a constituent, but not necessarily that the change
has been harmful. The major contaminant considered in
this paper is NO3), which is the most abundant, mobile,
and persistent agricultural contaminant in many shallow
groundwaters.
Irrigation, farming, and waste drainage in the study area
have altered groundwater fluxes and flow patterns. Agricultural contaminant loads in recharging groundwater
have resulted in well-known societal problems related to
drinking-water quality and ecological effects of ground-
Original article
Table 1
Hydrochemical analysis of I_ ncesu-Dokuzpınar springs
Parameters
T
pH
EC
Na
K
Ca
Mg
HCO3
SO4
Cl
Cu
Fe
Zn
Pb
Mn
Ni
Cd
Cr
B
SiO2
NO3
NO2
PO4
NH3
NH4
Units
(C)
–
(lS/cm)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
25 March
2000
12
7.3
377
41.00
5.50
18.00
11.50
103.82
11.88
70.90
0.532
0.103
0.14
0.127
0
0
0
0.022
1.615
5.675
16.01
0.01
0.151
0.068
0.4
16 October
2000
13
6.9
530
62.2
6
27
18
122
14.44
95.72
0.824
0.125
0.16
0
0
0
0
0.01
1.821
7.568
18.24
0.015
0.272
0.1
0.68
25 May
2001
12.5
7.1
320
78.4
7
24.5
17.75
158.2
16.47
120.5
0.639
0.1
0.1
0
0
0
0
0.015
1.652
5.962
16.96
0.01
0.184
0.094
0.5
Fig. 4
Periodic changes in ion concentrations
water discharge to surface-water bodies. In addition,
agricultural contaminants have caused substantial changes
in groundwater geochemistry and water-rock interactions,
which have received somewhat less attention. Global
trends indicate that agricultural effects on the hydrochemical cycle will continue to be important topics of
research in the future (Hem 1970).
The main sources of nitrate in the study area include:
nitrate from the application of fertilizers in irrigation and
from detergents in untreated waters. The common fertilizer applied liberally throughout the irrigation district is
(NH4)2SO4. Through a nitrification process in the presence
of oxygen, ammonium is transformed into nitrates according to the following reaction (Freeze and Cherry
1979).
Fig. 5
Periodic changes in the heavy-metal and nutrient concentrations
2O2 þ NHþ
4 ¼ NO3 þ H2 O
Greater mineralization is generally associated with the
higher nitrate concentrations of the I_ ncesu-Dokuzpınar
springs. The high nitrate concentrations may occur due to
the leaching of NO3 from fertilizers and biocides during
irrigation of agricultural land and leakage from overloaded
sewage networks are sources of NO3 pollution (Fig. 5).
Thick volcanic ash with clay layers in the study area
probably prevents or at least retards the introduction of
pollutants to the aquifer. The contrasting transport behavior of chemicals like NO3 and various pesticides makes
the design of management strategies for minimizing their
effects on ecosystems complicated. However, a high nitrate
content and significant mineralization in the groundwater
are probably due to contamination of the recharge to the
aquifer by irrigation drainage, deteriorated sewage networks, and septic tanks (APHA, AWWA, WPCF 1989).
Some other inorganic constituents of groundwaters that
are present in agricultural additives include Cl, K, Ca, Mg,
and a variety of minor elements. Agricultural sources of
some of these elements can dominate natural sources locally. Furthermore, agricultural effects on the recharge
fluxes of various ions like NO3 and H+ can cause changes
in weathering rates and ion-exchange equilibrium in the
subsurface, thereby altering indirectly the concentrations
of other constituents in groundwater. These indirect effects have important implications for geochemical studies
of water–rock interactions and can represent sources or
sinks for a variety of problematic contaminants such as
nutrients and toxic trace elements.
Finally, estimating the role of human activities on the
optimum yields of the springs for certain uses is important
for environmental balance and ecosystems. The high NO3,
NH3, NH4, and PO4 concentrations in the I_ ncesuDokuzpınar springs reflect the influence of liquid wastes,
frequent use of detergents, and widespread farming and
stockbreeding around the spring areas.
The discharge of liquid wastes that have nutritious organic
materials from the surrounding food, textile, and leather
factories into the receiver environment causes the
Environmental Geology (2003) 44:490–494
493
Original article
precipitation of intensive mud deposits and changes the
color of these deposits. These wastes have high heavymetal concentration, such as; B, Fe, Cu, Pb, and SiO2. This
type of water causes acidic influences at relatively different
rates in the discharge environment. Therefore, the
amount, distribution rates, and environmental effects of
the settlement, agricultural, and industrial waste ‘‘pollutants’’ around the spring area were investigated in detail.
Results and conclusions
Urbanization activities around Kayseri City affect the
groundwater quality in the shallow zones, depending on
the hydrological characteristics that control the flow and
dispersion of water and contaminants. The groundwater of
the Quaternary aquifer in the recharge area of the I_ ncesuDokuzpınar spring has great mineralization, high nitrate
pollution, and more depleted heavy metal contents, especially at the outlet points in the downstream side. The
thick clay and volcanic ash layers overlying the aquifer in
the upstream side have probably retarded the inflow of
younger water, which carries pollutants from irrigation
drainage and an overloaded sewage network. However, in
the downstream side of the I_ ncesu-Dokuzpınar area the
aquifer is more vulnerable to pollution.
Common agricultural practices have caused substantial
increases in the groundwater-recharge fluxes and concentrations of major elements and a variety of other heavy
metals. These increases have resulted in a transient agricultural chemical signal in aquifers that have groundwater
residence times of decades or more. Some elements are
added to the hydrosphere directly as components of fertilizers or other additives, whereas some are associated
indirectly with fertilizer loadings or land disturbance
through enhanced rates of leaching of natural sources in
soils, owing to physical and biological changes and to
increased acidity or ionic strength of agricultural recharge.
In addition, high fluxes of NH4 and NO3 in recharging
groundwater have resulted in unnaturally high concentrations of chemical species released from aquifer materials by oxidation reactions in the saturated zone, because
the electron demand of NO3 in agriculturally contaminated
recharge is commonly several times higher than that of
dissolved O2 in uncontaminated recharge.
Recommendations
Indirect human activities and agricultural effects on
groundwater composition are of geochemical significance
and can be useful as tracers of agricultural groundwater in
494
Environmental Geology (2003) 44:490–494
the study area. Although uncertainty and debate still exist
about the sources and pathways of NO3 in groundwater
recharge, several different types of evidence indicate that
excessive applications of artificial fertilizers and manures
have contributed substantially to the recharge rate of NO3
in many parts of the world.
Agricultural studies on the behavior of N and other important constituents in soils and crops have not been
coupled universally with studies that follow the progress of
those constituents below the root zone, in groundwater
recharge, and through aquifers.
In addition to the major constituents commonly associated with agricultural contamination, more work is needed
on the indirect effects that agricultural groundwater infiltration and recharge have on water–rock interactions, such
as leaching, weathering, and biogeochemical transformations in soils and aquifers, including dissolution and
precipitation of toxic or environmentally sensitive
elements that are not necessarily included in agricultural
additives.
Future applications of environmental tracers to agricultural contamination studies should include more sophisticated applications of multiple-tracer analyses to systems
with substantial transit times in the unsaturated zone and
the saturated zone, and to groundwater mixtures in discharges from wells and springs. Advances in the understanding of complex systems are expected to occur as
long-term trends in multiple-tracer data are developed at
individual sites, and by the application of more realistic
transport simulations for multiple tracers, including
agricultural contaminants.
Acknowledgements Sincere thanks are extended to the funding
group of the project that was provided by the Scientific and
Technical Research Council of Turkey (TÜBI_ TAK). I am also
grateful to my colleagues Yakup Kurmaç and Murat Kavurmacı,
who helped in the field and laboratory work for this project; the
reviews of the manuscript were also much appreciated.
References
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