『Abstract
The Buyukmelen River is expected to be a water source that can
supply the drinking water needs of Istanbul until 2040. The drinking
and utility water needs of Istanbul are to transport water from
the Buyukmelen River to Istanbul via pipeline and pump it into
the Akibeykoy and Omerli reservoirs when their water levels drop.
The Buyukmelen River is located in the province of Duzce in 170
km east of Istanbul and its water basin is approximately 2250
km2 The Buyukmelen River flows muddy in the rainy season
and into the Black Sea.
The chemical compositions of natural waters alter due to interaction
with geological formations, physical and chemical weathering of
various rocks and the effects of mining and agricultural production.
A research was conducted at the Buyukmelen River basin to determine
the effects of hydrological processes. Therefore, the samples
of rocks, soil, stream water, suspended and bed sediment were
collected from the Buyukmelen River basin. Geochemical and water
chemistry analyses of samples were performed at ALS Chemex laboratories,
Canada.
The bed sediments contain quartz, calcite, plagioclase, amphibole
and clay minerals. The clay minerals in the suspended and bed
sediment samples are kaolinites, smectite and illite.
The water samples collected from the Aksu, Kucukmelen, Asarsu
and Ugursuyu streams and the Buyukmelen River in winter (December
2005) and summer (June 2006) periods are rich in Ca and HCO3 ions. The ions most abundant in rainfall sample
are HCO3 and Na. The ion compositions of
surface waters have increased due to the weathering of limestone,
agglomerate and volcanic sandstones, light acidic rainfall, semi-arid
Black Sea climate in the Buyukmelen basin. The suspended sediment
amount of the Buyukmelen River in the rainy season (December 2005)
is 174 mg/l.
According to the water contamination regulation of Turkey, the
Buyukmelen Rivers belongs to quality class 4 based on Al ion and
to quality class 3 based on Fe ion in winter period, and to quality
class 2 based on Mn concentration in summer period.
Chemical index of alteration (CIA) indices observed in the suspended
and bed sediments (average of 55) suggest that their source area
underwent moderate degrees of chemical weathering processes. According
to Upper Continental Crust (UCC) values, the suspended sediment
was rich in elements such as Fe2O3,
CaO, MgO, MnO, TiO2, P2O5, V, Cr, Co, Cu, Zn, As, Cd, Sb, Hg and Pb. The
element concentrations of the suspended sediments were related
to size fractionation, mainly of clay content. The mentioned enrichment
was contributed by agglomerate, basalt, volcanic sandstone and
graywacke from rocks in the study area. Source of ions such as
l, Fe, Mn, Ba, Cr, Co, Cu, Ni, Ti and Hg and major in Buyukmelen
River is interaction with rocks such as the agglomerate, basalt,
andesite, volcanic sandstone and graywacke.
As suggested by Singh et al. (2005), before weathering of some
rocks in the Buyukmelen River basin, it was determined that they
were graywacke and literanite based on the geochemistry of the
suspended and bed sediments.
Keywords: Bed sediment; Hydrogeochemistry; River water; Suspended
sediment; Turkey; Weathering; Water quality』.
1. Introduction
2. Geography and climate
3. Materials and methods
4. Geological setting
4.1. Structural geology
4.2. Hydrogeology
5. Mineralogy
5.1. Particle size in samples of bed sediment
5.2. Mineralogical composition of rock, soil, suspended and bed
sediment samples
6. Geochemistry and weathering
6.1. Chemical index of alteration (CIA) and chemical mobility
7. Hydrogeochemical characteristics
7.1. Major ion content of stream waters
7.2. Water-rock interaction
7.3. Heavy metal content of stream waters in the Buyukmelen River
basin
8. Results and discussion
Acknowledgements
References