243
from the families Cucurbitaceae, Solanaceae, and Brassicaceae is the main agricultural product since the 1980s.
Groundwater of the Strumica/Strumeshnitsa river basin belongs to the Petrich
valley aquifer shared by the Republic of North Macedonia and Bulgaria. The aquifer is made up of Pliocene, predominantly, and Quaternary lake sediments and alluvial sands, gravels, clays, and sandy clays (UNECE 2011). The Strumica river is
transboundary tributary to the Struma/Strymonas river which source is in western
Bulgaria (Vitosha Mountain, south of Sofia) and ends in the Aegean Sea (Strymonikos
Gulf – Greece) (Fig. 8.1).
The intensive agriculture production makes this area vulnerable regarding fertilizer and pesticide application as well as sewage and manure leaching. The average
air temperature and precipitation are 12.7 °C and 604 mm, respectively. According
to Ivanova and Ambarkova (2015), a compact groundwater type with water level
under pressure is present (artesian well at a depth of 180–160 m) in the region and
the well capacity of 10–20 l/s. Gorgieva et al. (2000) classified the groundwater in
the investigated region as highly vulnerable regarding the poor technical condition,
no flow regulation in the convey structures, unregulated use, and the decrease of
precipitation. The main use of groundwater in the Strumica region is for irrigation
and only small part for water supply and industry.
8.2.2 Sampling and Analysis
8.2.2.1 Groundwater Sampling
A total number of 185 groundwater samples were collected from existing boreholes
on agriculture land during April, May, and June 2014 and 2015 (Fig. 8.1). Samples
were collected according to the EPA guidelines (Johnston 2007). For that purpose,
groundwater was left to flow until the conductivity stabilization and collected in
clean glass bottles which were transferred in 2 hours, preserved, and kept on 4 °C
until the analysis.
8.2.2.2 Chemical Analysis
Groundwater was analyzed for the quantity of major cations (Ca, Mg, Fe, K, Mn,
Na), anions (CO 3 , HCO 3 , Cl, NO 3 , SO 4 ), heavy metals, and trace elements (As, Al,
B, Be, Cu, Cr, Co, Cd, Li, Mg, Mo, Ni, Pb, Ti, V, Zn). Anions like chlorine, carbonate, and bicarbonate were analyzed by volumetric methods. Sulfate (SO 4
2−
), nitrate
(NO 3
−
), nitrite (NO 2
−
), and ammonia (NH 4
+
) were determined by the colorimetric
method using spectrophotometer type JENWAY 6715, UV-Vis (US EPA Methods
375.4 1978; US EPA Methods 352.1 1971; US EPA Methods 354.1 1971; US EPA
Methods 350.2 1974). pH is measured by pH meter HANNA HI 2211-01, and electrical conductivity is measured using the conductometer JENWAY 4520, in situ.
8 Groundwater Pollution Under the Intensive Agriculture Production
from the families Cucurbitaceae, Solanaceae, and Brassicaceae is the main agricultural product since the 1980s.
Groundwater of the Strumica/Strumeshnitsa river basin belongs to the Petrich
valley aquifer shared by the Republic of North Macedonia and Bulgaria. The aquifer is made up of Pliocene, predominantly, and Quaternary lake sediments and alluvial sands, gravels, clays, and sandy clays (UNECE 2011). The Strumica river is
transboundary tributary to the Struma/Strymonas river which source is in western
Bulgaria (Vitosha Mountain, south of Sofia) and ends in the Aegean Sea (Strymonikos
Gulf – Greece) (Fig. 8.1).
The intensive agriculture production makes this area vulnerable regarding fertilizer and pesticide application as well as sewage and manure leaching. The average
air temperature and precipitation are 12.7 °C and 604 mm, respectively. According
to Ivanova and Ambarkova (2015), a compact groundwater type with water level
under pressure is present (artesian well at a depth of 180–160 m) in the region and
the well capacity of 10–20 l/s. Gorgieva et al. (2000) classified the groundwater in
the investigated region as highly vulnerable regarding the poor technical condition,
no flow regulation in the convey structures, unregulated use, and the decrease of
precipitation. The main use of groundwater in the Strumica region is for irrigation
and only small part for water supply and industry.
8.2.2 Sampling and Analysis
8.2.2.1 Groundwater Sampling
A total number of 185 groundwater samples were collected from existing boreholes
on agriculture land during April, May, and June 2014 and 2015 (Fig. 8.1). Samples
were collected according to the EPA guidelines (Johnston 2007). For that purpose,
groundwater was left to flow until the conductivity stabilization and collected in
clean glass bottles which were transferred in 2 hours, preserved, and kept on 4 °C
until the analysis.
8.2.2.2 Chemical Analysis
Groundwater was analyzed for the quantity of major cations (Ca, Mg, Fe, K, Mn,
Na), anions (CO 3 , HCO 3 , Cl, NO 3 , SO 4 ), heavy metals, and trace elements (As, Al,
B, Be, Cu, Cr, Co, Cd, Li, Mg, Mo, Ni, Pb, Ti, V, Zn). Anions like chlorine, carbonate, and bicarbonate were analyzed by volumetric methods. Sulfate (SO 4
2−
), nitrate
(NO 3
−
), nitrite (NO 2
−
), and ammonia (NH 4
+
) were determined by the colorimetric
method using spectrophotometer type JENWAY 6715, UV-Vis (US EPA Methods
375.4 1978; US EPA Methods 352.1 1971; US EPA Methods 354.1 1971; US EPA
Methods 350.2 1974). pH is measured by pH meter HANNA HI 2211-01, and electrical conductivity is measured using the conductometer JENWAY 4520, in situ.
8 Groundwater Pollution Under the Intensive Agriculture Production