228
extraction efficiencies showed satisfactory results for all investigated pesticides
except for methomyl and metribuzin. The recovery study performed from a spiked
water sample at 0.1 μg/l showed satisfied recovery in the range from 68 to 117%
using LLE with methylene chloride (Figs. 7.3, 7.4 and 7.5). LODs were in the range
of 0.001–0.388 ng/μl; LOQs were in the range of 0.005–1.17 ng/μl. RSD was lower
than 10% for all compounds (Table 7.8). The proposed method was validated for
benalaxyl, buprofezin, chlorpyrifos, pirimiphos methyl, pyrimethanil, pirimicarb, and
triadimenol and used for identification of pesticides in groundwater.
7.3.2 Groundwater Quality
7.3.2.1 Pesticides in Groundwater Samples
Pesticides can reach water-bearing aquifers below ground from applications onto
crop fields, seepage of contaminated surface water, accidental spills and leaks,
improper disposal, and even through injection waste material into wells.
In this study 15% of investigated groundwater samples show the presence of
pesticides. Pyrimethanil and chlorpyrifos were identified in 3 out of 20 investigated
groundwater samples in a maximum concentration of 0.3392 μg/l (Table 7.9).
Chlorpyrifos was widely used in agriculture for the control of soil and foliar pests
before it was banned in the European Union in January 2020. It is an organophosphate volatile compound that has low aqueous solubility and low soil mobility.
Based on these chemical properties, it is considered that chlorpyrifos possesses a
low risk of leaching to groundwater. Despite this, it is found in groundwaters worldwide like Pakistan (Tariq et al. 2007), New Zealand (Close and Skinner 2012),
Argentina (Loewy et al. 2011), Brazil (Bortoluzzi et al. 2007), Turkey (Tuncel et al.
2008), Australia (Wightwick and Allinson 2007), Spain (Teijon et al. 2010), Ireland
(Estévez et al. 2012), Greece (Vryzas et al. 2012), Portugal (Silva et al. 2011), the
Table 7.7 Tukey HSD post
hoc test between the groups
(q = 2.93; critical
value 47,465)
Comparison
Absolute mean difference
10 psi vs 20 psi 25,085
10 psi vs 30 psi 43,273
10 psi vs 40 psi 53,756
10 psi vs 50 psi 60,064
20 psi vs 30 psi 18,188
20 psi vs 40 psi 28,670
20 psi vs 50 psi 85,150
30 psi vs 40 psi 10,482
30 psi vs 50 psi 103,338
40 psi vs 50 psi 113,821
Significant values are marked with bold
q studentized range distribution
B. Kovacevik et al.
extraction efficiencies showed satisfactory results for all investigated pesticides
except for methomyl and metribuzin. The recovery study performed from a spiked
water sample at 0.1 μg/l showed satisfied recovery in the range from 68 to 117%
using LLE with methylene chloride (Figs. 7.3, 7.4 and 7.5). LODs were in the range
of 0.001–0.388 ng/μl; LOQs were in the range of 0.005–1.17 ng/μl. RSD was lower
than 10% for all compounds (Table 7.8). The proposed method was validated for
benalaxyl, buprofezin, chlorpyrifos, pirimiphos methyl, pyrimethanil, pirimicarb, and
triadimenol and used for identification of pesticides in groundwater.
7.3.2 Groundwater Quality
7.3.2.1 Pesticides in Groundwater Samples
Pesticides can reach water-bearing aquifers below ground from applications onto
crop fields, seepage of contaminated surface water, accidental spills and leaks,
improper disposal, and even through injection waste material into wells.
In this study 15% of investigated groundwater samples show the presence of
pesticides. Pyrimethanil and chlorpyrifos were identified in 3 out of 20 investigated
groundwater samples in a maximum concentration of 0.3392 μg/l (Table 7.9).
Chlorpyrifos was widely used in agriculture for the control of soil and foliar pests
before it was banned in the European Union in January 2020. It is an organophosphate volatile compound that has low aqueous solubility and low soil mobility.
Based on these chemical properties, it is considered that chlorpyrifos possesses a
low risk of leaching to groundwater. Despite this, it is found in groundwaters worldwide like Pakistan (Tariq et al. 2007), New Zealand (Close and Skinner 2012),
Argentina (Loewy et al. 2011), Brazil (Bortoluzzi et al. 2007), Turkey (Tuncel et al.
2008), Australia (Wightwick and Allinson 2007), Spain (Teijon et al. 2010), Ireland
(Estévez et al. 2012), Greece (Vryzas et al. 2012), Portugal (Silva et al. 2011), the
Table 7.7 Tukey HSD post
hoc test between the groups
(q = 2.93; critical
value 47,465)
Comparison
Absolute mean difference
10 psi vs 20 psi 25,085
10 psi vs 30 psi 43,273
10 psi vs 40 psi 53,756
10 psi vs 50 psi 60,064
20 psi vs 30 psi 18,188
20 psi vs 40 psi 28,670
20 psi vs 50 psi 85,150
30 psi vs 40 psi 10,482
30 psi vs 50 psi 103,338
40 psi vs 50 psi 113,821
Significant values are marked with bold
q studentized range distribution
B. Kovacevik et al.