International  Journal  of
Environmental Research
and Public Health
Article
Occurrence of Banned and Currently Used Herbicides, In
Groundwater of Northern Greece: A Human Health Risk
Assessment Approach
Paraskevas Parlakidis 1, Maria Soledad Rodriguez 1,2, Georgios D. Gikas 3 , Christos Alexoudis 1,
Greivin Perez-Rojas 1,4, Marta Perez-Villanueva 1,4 , Alejo Perez Carrera 2, Alicia Fernández-Cirelli 2
and Zisis Vryzas 1,*
1 Laboratory of Agricultural Pharmacology and Ecotoxicology, Department of Agricultural Development,
Democritus University of Thrace, 68200 Orestias, Greece; pparlaki@agro.duth.gr (P.P.);
solerodrigez@gmail.com (M.S.R.); calexoud@agro.duth.gr (C.A.); greperez@gmail.com (G.P.-R.);
marta.perez@ucr.ac.cr (M.P.-V.)
2 Centro de Estudios Transdisciplinarios del Agua/CETA (UBA), Instituto de Investigaciones en Producción
Animal/INPA (CONICET), Facultad de Ciencias Veterinarias, Universidad de Buenos Aires,
Buenos Aires C1427CWO, Argentina; ceta@fvet.uba.ar (A.P.C.); inpa@fvet.uba.ar (A.F.-C.)
3 Laboratory of Ecological Engineering and Technology, Department of Environmental Engineering,
School of Engineering, Democritus University of Thrace, 67100 Xanthi, Greece; ggkikas@env.duth.gr
4 Centro de Investigación en Contaminación Ambiental (CICA), Universidad de Costa Rica,
San Jose 2060, Costa Rica
* Correspondence: zvryzas@agro.duth.gr
Citation: Parlakidis, P.; Rodriguez, Abstract: The presence of pesticide residues in groundwater, many years after their phase out in
M.S.; Gikas, G.D.; Alexoudis, C.; European Union veries that the persistence in aquifer is much higher than in other environmental
Perez-Rojas, G.; Perez-Villanueva, M.; compartments. Currently used and banned pesticides were monitored in Northern Greece aquifers
Carrera, A.P.; Fernández-Cirelli, A.; and a human health risk assessment was conducted. The target compounds were the herbicides
Vryzas, Z. Occurrence of Banned and
metolachlor (MET), terbuthylazine (TER), atrazine (ATR) and its metabolites deisopropylatrazine
Currently Used Herbicides, In
(DIA), deethylatrazine (DEA) and hydroxyatrazine (HA). Eleven sampling sites were selected to
Groundwater of Northern Greece: A
Human Health Risk Assessment have representatives of different types of wells. Pesticides were extracted by solid-phase extraction
Approach. Int. J. Environ. Res. Public and analyzed by liquid chromatography. MET was detected in 100% of water samples followed
Health 2022, 19, 8877. https:// by ATR (96.4%), DEA and HA (88.6%), DIA (78.2%) and TER (67.5%). ATR, DIA, DEA, HA, MET
doi.org/10.3390/ijerph19148877 and TER mean concentrations detected were 0.18, 0.29, 0.14, 0.09, 0.16 and 0.15 µg/L, respectively.
Obtained results were compared with historical data from previous monitoring studies and temporal
Academic Editor: Paul
trends were assessed. Preferential ow was the major factor facilitating pesticide leaching within the
B. Tchounwou
month of herbicide application. Moreover, apparent age of groundwater and the reduced pesticide
Received: 4 June 2022 dissipation rates on aquifers resulted of long-term detection of legacy pesticides. Although atrazine
Accepted: 19 July 2022 had been banned more than 18 years ago, it was detected frequently and their concentrations in
Published: 21 July 2022 some cases were over the maximum permissible limit. Furthermore, human health risk assessment
Publisher’s Note: MDPI stays neutral of pesticides was calculated for two different age groups though drinking water consumption. In
with regard to jurisdictional claims in all examined wells, the sum of the HQ values were lower than the unity. As a result, the analyzed
published maps and institutional afl- drinking water wells are considered safe according to the acute risk assessment process. However,
iations. the presence of atrazine residues causes concerns related with chronic toxicity, since ATR R values
were greater than the parametric one of 1 × 10−6 advised by USEPA, for both age groups.
Keywords: herbicides; metabolites; banned pesticides; groundwater; preferential ow; leaching
Copyright: © 2022 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons 1. Introduction
Attribution (CC BY) license (https:// Safe drinking water from surface- and ground-water is essential for human health,
creativecommons.org/licenses/by/ quality of life and socio-economic development of humanity and is a prerequisite factor
4.0/). for the human population [1]. The largest body of freshwater in the European Union
Int. J. Environ. Res. Public Health 2022, 19, 8877. https://doi.org/10.3390/ijerph19148877 https://www.mdpi.com/journal/ijerph
Int. J. Environ. Res. Public Health 2022, 19, 8877 2 of 16
(EU) is groundwater. In Greece, groundwater contributes to 13.9% of all renewable water
resources. In Greece, the annual water consumption/requirements are mainly covered
by groundwater use representing 36% in farming, 5% in public use and 1% in industrial
production. Hence, the usual geophysical peculiarities of Greece render the groundwater
pumping as the only source of drinking water [2].
Herbicides are generally considered the most economical and effective way to control
weeds in agricultural and non-crop environments [3]. However, the increasing use of
herbicides leads to natural waters contamination inducing public health and environmental
threats. For instance, the toxicity effects of pesticides to non-target organisms, such as
microbiota, sh, algae and aquatic invertebrates, were reported repeatedly by several
authors [4,5]. Several factors can affect pesticides and their metabolites behavior in the
environment. Physicochemical properties of pesticides such as ionization, water solubility,
volatility, octanol-water partition coefcient, thermo-, photo- and hydrolysis stability
combined with the soil properties including organic carbon content, texture, pH, clay
mineral type, dissolved organic matter and cation exchange capacity have important roles
on run-off, adsorption or leaching potential. Rainfall and irrigation intensity, biological
processes (biodegradation) and the agricultural practices affect pesticide fate, too [6,7].
Point or nonpoint source pesticide pollution can cause groundwater contamination through
leaching. Pesticides residues can reach groundwater in a short time (preferential ow)
by macropores reducing the potential to be absorbed by soil or to be biodegraded [8].
Alternatively, pesticides may move through soil micropores slowly (matrix ow) and are
available to interact with soil particles and microorganisms [9]. ATR, MET and TER have
long DT50 values and low absorptivity in soil, which increase their potential to contaminate
groundwaters [10,11].
Various directives regulated the presence of pesticides in groundwater such as Ground
Water Directive [12], Drinking Water Directive [13], Water Framework Directive [14] and
Directives about priority substances and environmental quality standards in the eld of
water policy [15]. The quality standards of drinking water, related to pesticides in EU, were
set with maximum concentration of 0.1 µg/L and 0.5 µg/L of the presence of individual and
total pesticides and metabolites, respectively [13]. In addition, EU has set environmental
quality standards (EQS) for surface water bodies in the eld of water policy for priority
substances and certain other pollutants, including pesticides. According to this directive,
the annual average EQS for atrazine was set to 0.6 µg/L and the maximum allowable EQS
was set to 2 µg/L [15].
Recent studies showed that ATR is an endocrine disruptor causing disfunctions at
normal human reproduction and development for both genders [16]. Furthermore, ATR
was correlated to potential neurological and liver problems [5,17]. Regarding TER, humans
are usually exposed to herbicide by inhalation and dermal contact, but the main exposure
pathway is oral, through drinking water consumption [18]. Moreover, the TER and its
metabolite desethyl-terbuthylazine were detected in hair samples of farm workers, but
only slight to moderate irritation to the eyes and skin were observed [19]. MET belongs to
Toxicity Category III for acute dermal, oral and inhalation effects, and to Toxicity Category
IV for dermal and eye irritation [20]. Thorpe and Shirmohammadi [21] showed that
the exposure of a mixture of herbicides containing MET to children caused a 7.6-fold
increased chance of developing bone or brain cancer, leukemia and lymphoma compared
to unexposed children. Hence, in Iowa and North Carolina, an increased risk of lung and
prostate cancer was observed, when farmers were exposed to MET [22].
Northern Evros is one of the most important regions of agricultural economy in Greece.
In addition, the extensive agricultural activity, the vicinity with transboundary rivers and
different agricultural practices followed in Bulgaria and Turkey increase the complexity
of studying the origin of pesticide pollution. Previous monitoring studies of Northern
Evros showed medium detection frequency of ATR, MET, TER and ATR metabolites, e
DIA, deethylatrazine (DEA) and HA [2,23]. Interestingly, despite the ban, ATR and its
metabolites and MET have been frequently detected in high concentrations including water
Int. J. Environ. Res. Public Health 2022, 19, 8877 3 of 16
quality standards exceedances in numerous European countries such as Spain, Slovenia,
Hungary, Portugal and Germany, over last decade [24–28]. High concentrations of TER
were detected, too. For example, the maximum detected concertation in groundwaters
in the Águeda River Basin from Spain and Portugal was 2.5 µg/L [24]. Surprisingly,
a serious lack of human health risk assessment studies in groundwater is observed in
Europe. Therefore, the aim of this study was to investigate the groundwater quality, the
presence and the persistence of these compounds (i.e., ATR and its metabolites, MET and
TER), and to characterize their temporal and spatial variability in the studied aquifer,
18 years after atrazine’s ban. Moreover, a chronic risk assessment of side effects on human
health by consumption of contaminated drinking water was conducted. According to our
knowledge, this study is the rst attempt to correlate the human health risk assessment
with the determination of pesticides residues in groundwater in Balkans and by extension
in Greece.
2. Materials and Methods
2.1. Study Area Description
Sampling area was chosen taking into account the persistence of target pesticides in
groundwater in Northern Evros, Thrace District, North Greece, as reported by previous
studies and the extensive cultivation of wheat (2313.63 ha), cotton (2286.54 ha), sunowers
(1817.71 ha), maize (1695.18 ha) and beets (322.39 ha). Therefore, samples were taken from
11 sampling points, at Ardas Valley (third biggest arable area in Greece), divided in three
Groups A sampling network of shallow groundwater was established during a previous
study 20 years ago consisted of 4 experimental boreholes (Group A) [2]. Furthermore,
5 drinking water wells were included, which supply Orestiada town and local villages with
potable water (Group B). In addition, two active irrigation wells were chosen (Group C) to
include all available well types. Therefore, the sampling groups form was: Group A: A1,
A2, A3 and A4, Group B: B1, B2, B3, B4 and B5 and Group C: C1 and C2. Sampling sites
were located close to villages Rizia (A1, B1, C2), Keramos (A2), Plati (A3), Fylakio (A4, B2,
C1), Elia (B3), Arzos (B4) and Kastanies (B5) (Figure 1).
Figure 1. Study area of a transboundary aquifer (among Greece, Turkey and Bulgaria) and sampling
sites. The capital letters A, B and C represent the experimental boreholes, drinking water wells and
irrigation wells, respectively. Numbering identies the villages close to sampling sites.
Int. J. Environ. Res. Public Health 2022, 19, 8877 4 of 16
Sampling was performed on a monthly basis for the period 28 March–5 September
2018, conducting 5 samplings. The samples (volume of 1 L) in triplicate were poured in
dark polypropylene bottles. Then, they were transported to the Laboratory of Agricultural
Pharmacology and Ecotoxicology, Department of Agricultural Development, at Democritus
University of Thrace in ice-boxes and were stored in the dark at temperatures below−20 ◦C
until analysis that was performed within a period no longer than 1 week. Experimental
borehole samples were manually pumped using an experimental tube. The drinking
water and irrigation wells were equipped with a pump system and samples were collected
automatically before chlorination stage.
2.2. Chemicals and Instrumental Analysis
The pesticide standards had the highest available purity (>97%) and were purchased
by Dr. Ehrestrofer GmbH (Augsburg, Germany). Physicochemical properties of studied
compounds are shown in Table 1. The HPLC grades, acetonitrile, ethyl acetate, water and
methanol for liquid chromatography were purchased by Riedel de Haen (Seelze, Germany).
LiChrolut® EN Polymer-based solid-phase extraction cartridges with 200 mg absorbent
and 3 mL volume were purchased by Merck (Darmastdt, Germany).
Table 1. Physicochemical properties of target compounds [29].
Soil Dissociation Water Octanol-Water Vapour
Compound Degradation Constant (pKa) Solubility at Partition GUS Leaching
DT (Field) at 25 ◦C 20 ◦C (mg/L) Coefcient at Pressure at
20 ◦C (mPa) Potential Index
50 20 ◦C (LogKow)
ATR 29 1.7 35 2.7 0.039 2.57
DIA - - 980 1.15 - -
DEA 45 - 2700 1.5 12.44 3.24
HA - - 5.9 2.09 1.131
MET 21 - 530 3.4 1.7 2.36
TER 21.8 1.9 6.6 3.4 0.152 2.19
ATP: atrazine, DIA: deisopropylatrazine, DEA: deethylatrazine, HA: hydroxyatrazine, MET: metolachlor and
TER: terbuthylazine.
Groundwater samples were prepared for instrumental analysis using solid phase ex-
traction (SPE) for the multi-residue analysis as described by Papadakis and Papadopoulou-
Mourkidou [30] with slight modications. Water samples of 1 Lwere extracted by cartridges
which were preconditioned with adding of 4 mL methanol followed by 4 mL deionized
water. Samples were passed through cartridges at a ow rate of 5 mL/min. Target com-
pounds were eluted with 7 mL methanol followed by 3 mL ethyl acetate. Next, samples
were concentrated under nitrogen stream at 50 ◦C. Finally, samples were dissolved with
1.25 mL of methanol and stored at −20 ◦C until instrumental analysis.
Samples were analyzed by a HPLC/DAD equipped with autosampler (Finnigan
Surveyor, Thermo Scientic, Boston, MA, USA). The analytical column C18 Speedcore
100 × 4.6 mmwas purchased by Fortis Technologies Ltd. (Cheshire, UK). Chromatographic
data were processed by the ChromQuest 5.0 software (Finnigan Surveyor, Thermo Scien-
tic). The mobile phase was consisted of acetonitrile (A) and water (W). The ow was
set at 1.0 mL/min and the gradient included the following steps: the elution began at
20-80/A-W, 20-80/A-W (0–20 min), 95-5/W-A (20–25 min), 95-5/A-W (25–26 min) and
20-80/A-W (26–33 min). Total run time was 40 min. The injection volume was 25 µL. The
column oven temperature was adjusted at 30 ◦C. MET, TER, DEA and DIA were detected at
220 nm, while ATR and HA at 240 nm. For further conrmation of the target peaks, the UV
absorption spectra taken at the apex of each sample were compared with those obtained
from the standard solutions and control spiked samples. The quantication was performed
using external working standard calibration curves (1, 10, 50 and 100 µg/mL). The accuracy
(recovery) and precision (repeatability) of the analytical method were evaluated with the
analysis of fortied (at 0.1 µg/g and 0.5 µg/g) tap water samples in duplicate. The limits
Int. J. Environ. Res. Public Health 2022, 19, 8877 5 of 16
of detection (LOD, µg/L) were determined as the lowest concentrations giving a response
of three times the baseline noise of the analysis of three control samples. The limits of quan-
tication (LOQ, µg/L) were determined as the lowest concentrations of a given compound
in fortied samples that could be quantied with relative standard deviation lower than
20%. Positive detections of ATR, DIA, DEA, MET and TER were also conrmed with gas
chromatographic analysis using a Trace 2000 gas chromatograph connected with the GCQ
plus ion-trap mass spectrometer (Thermoquest, Austin, TX, USA). Gas chromatographic
analysis was carried out on a 30 m × 0.25 mm I.D., 0.25 µm lm thickness CP-SIL 8 CB (5%
phenyl, 95% dimethylpolysiloxane) low bleed/MS column (Varian Analytical Instruments,
Middelburg, The Netherlands) and the GC and MS operational conditions were those
mentioned by Vryzas et al. [31]. Fortied tap water samples were used for the validation
of the analytical method. Fortication levels includes the LODs, LOQs and the 0.1 µg/L.
For all compound the LODs were ranged from 0.001 to 0.005 µg/L and LOQs from 0.01 to
0.05 µg/L. The recoveries were higher than 86% for all compounds with relative standard
deviation lower than 15% at tested fortication levels.
2.3. Human Health Risk Assessment
Human health risk assessment was conducted for atrazine, metolachlor and terbuthy-
lazine. According to Kim et al. [32] human health risk assessment of pesticides can provide
information about the probability and the kind of effects to human population. In this case,
oral exposure through drinking water consumption was considered as pathway to people.
Risk assessment was divided to carcinogenic and non-carcinogenic and to two age groups,
adults and children. Drinking water was provided to the local population by wells located
close to the villages Elia, Arzos, Fylakio, Rizia and Kastanies (Figure 1).
2.4. Chronic Daily Intake (CDI)
CDI shows the estimated intake amount of pesticide per kilogram body weight
(Equation (1)):
DIP × EFi × ED
CDIi = i
BWi ×
(1)
AT
where DIP is the average daily intake, EFi is the exposure frequency (365 days per year for
both age groups), EDi is the exposure duration (6 and 70 years for children and adults,
respectively), BWi is equal to 70 kg for adults and 20 kg for children and AT is the average
lifespan (2190 and 25,550 days for children and adults, respectively). The determination of
the average daily intake (DIP) was estimated using the Equation (2), which was suggested
by Muhammad et al. [33], Papadakis et al. [4] and Ali et al. [34]:
DIP= Ci × IRi (2)
where Ci (µg/L) represents extreme and mean concentration of pesticide residues and IRi
shows the intake rate of water (0.87 L/day for children and 1.41 L/day for adults).
2.5. Hazard Quotient (Non-Carcinogenic Risk Assessment)
To calculate the hazard quotient (HQ), CDI was divided with the respective reference
dose of each compound (Equation (3)):
HQ = CDIi/RfD (3)
where RfD is the acute toxicity reference dose [35].
The RfD values for atrazine, metolachlor and terbuthylazine, were 0.035, 0.015 and
0.008 (mg/kg-day), respectively [36,37]. When HQ values are equal or greater than 1, the
exposed part of population is under health risk.
Int. J. Environ. Res. Public Health 2022, 19, 8877 6 of 16
Multiple pesticides residues risk (HQs) can be calculated by the sum of HQ for indi-
vidual pesticide using the Equation (4):
HQs ∑n
= i 1 HQi (4)
=
2.6. Carcinogenic Risk Assessment
Carcinogenic risk (R) was calculated by the Equation (5) [4,32]:
R = CDI × SF × ADAF (5)
where SF is the cancer slope factor (mg/kg-day), which reects the possibility of the
individual pesticide to cause cancer and ADAF is an age factor considering the early life
pesticide exposure (3 for children and 1 for adults). Among the studied pesticides the only
available SF value is for atrazine with value 0.22, provided by IRIS [36].
2.7. Statistical Analysis
An analysis of variance was conducted (ANOVA) for human health risk results using
a mixed linear model according to Mas et al. [38]. The calculations were performed using
the Excel Solver Add-in Package.
3. Results and Discussion
3.1. Concentrations and Detection Frequency
The sampling sites were in the Ardas valley, an aquifer vulnerable to pesticide contam-
ination according to previous studies [5,23]. In general, the mean concentrations presented
a wide range of values exceeding, occasionally, the maximum permissible limit of 0.1 µg/L
in experimental boreholes (group A), drinking water wells (group B) and irrigation wells
(group C) (Table 2).
Table 2. Statistics of pesticides concentrations (µg/L).
Sampling Sites
Parameter
A1 A2 A3 A4 B1 B2 B3 B4 B5 C1 C2
Mean 0.02 0.23 0.10 0.28 0.23 0.45 0.03 0.05 0.30 0.20 0.14
Median <0.00 0.01 0.01 0.01 0.11 0.18 0.02 0.01 0.24 0.16 0.17
ATR Max 0.07 0.50 0.30 0.55 0.63 1.86 0.06 0.05 0.49 0.56 0.26
n 5 5 5 5 5 5 5 5 5 5 5
Mean 0.06 0.05 0.06 0.14 0.14 0.09 0.26 0.08 0.22 1.99 0.06
Median 0.02 <0.00 0.02 <0.00 0.15 0.09 0.20 0.02 0.22 2.01 0.04
DIA Max 0.14 0.14 0.12 0.45 0.12 0.13 0.49 0.15 0.31 2.91 0.14
n 5 5 5 5 5 5 5 5 5 5 5
Mean 0.13 0.05 0.05 0.18 0.13 0.05 0.17 0.05 0.28 0.23 0.20
Median 0.01 0.01 <0.00 <0.00 0.09 0.01 0.07 0.03 0.32 0.32 0.20
DEA Max 0.46 0.05 0.05 0.65 0.27 0.05 0.45 0.06 0.13 0.42 0.55
n 5 5 5 5 5 5 5 5 5 5 5
Mean 0.07 0.30 0.05 0.07 0.05 0.05 0.08 0.05 0.06 0.13 0.10
Median 0.05 0.01 0.02 0.00 0.01 0.02 0.05 0.01 0.06 0.06 0.05
HA Max 0.20 0.08 0.07 0.27 0.32 0.08 0.16 0.05 0.46 0.30 0.29
n 5 5 5 5 5 5 5 5 5 5 5
Mean 0.18 0.60 0.11 0.24 0.06 0.05 0.06 0.05 0.22 0.10 0.14
Median <0.00 <0.00 0.04 <0.00 0.05 0.01 0.03 <0.00 0.13 0.11 0.12
MET Max 0.58 0.23 0.20 0.93 0.12 0.04 0.15 0.05 0.52 0.17 0.41
n 5 5 5 5 5 5 5 5 5 5 5
Mean 0.02 0.45 0.05 0.15 0.25 0.14 0.05 0.04 0.16 0.20 0.09
Median 0.01 0.80 <0.00 0.10 0.21 0.16 0.02 <0.00 0.17 0.11 0.13
TER Max 0.06 1.00 0.20 0.34 0.16 0.36 0.07 0.11 0.16 0.56 0.16
n 5 5 5 5 5 5 5 5 5 5 5
n = number of samples in triplicate.
Int. J. Environ. Res. Public Health 2022, 19, 8877 7 of 16
According to the results shown in Table 3, the ATR mean concentration was above
0.1 µg/L in A2 and A4 sites. DIA mean concentration was found higher than 0.1 µg/L
in A4, while HA surpassed it in A2. DEA mean concentration were higher than 0.1 µg/L
in A1 and A4. TER presented limit exceedances in A2 and A4 and MET in all boreholes.
As far as drinking water wells, ATR showed higher mean concentration than 0.1 µg/L in
B1, B2 and B5. DIA mean concentration was higher in B1, B3 and B5. In HA case, mean
concentration was above the limit in all drinking water wells. The mean concentration of
MET was higher than 0.1 µg/L in B5, while TER limit exceedances were found in B1, B2
and B3. Concerning the irrigation wells, exceedances of 0.1 µg/L were observed for ATR,
and DEA in both wells, for MET in C2 and for HA, DIA and TER in C1. Furthermore, the
highest concentration of ATR, DIA, DEA, HA, MET and TER were 1.86, 2.91, 0.65, 0.46, 0.93
and 1.0 µg/L, respectively (Table 3).
Table 3. Summary of positive samples in pesticide residues and exceedances of the EU permissible limit.
Sampling Sites Positive Samples (%) ** Samples with Concentration Higher than 0.1 µg/L (%)
N * ATR DIA DEA HA MET TER ATR DIA DEA HA MET TER
A1 5 80 80 60 60 80 60 0 40 20 20 40 0
A2 5 80 80 80 80 80 40 0 20 0 0 20 40
A3 5 80 80 40 80 80 20 40 20 0 0 40 20
A4 5 80 80 40 80 80 60 40 40 20 20 20 60
BI 5 80 100 100 80 100 100 60 60 40 0 40 100
B2 5 80 100 100 80 100 60 60 40 0 0 0 60
B3 5 100 100 100 100 100 80 0 100 40 40 20 0
B4 5 80 80 80 80 80 40 0 40 0 0 0 20
B5 5 100 100 100 100 100 80 100 100 80 40 60 80
C1 5 100 100 100 60 100 80 60 100 60 40 60 80
C2 5 100 100 100 100 100 80 60 40 60 40 60 60
Total 55 87.3 90.9 81.8 81.8 90.9 63.6 38.2 54.5 29.1 18.2 32.7 47.3
* Number of samples in triplicate. ** Positive samples in pesticide residues are considered when pesticide
concentrations are ≥ of LOQs.
Table 4 presents the percentage of positive samples in pesticide residues and the per-
centage of samples with concentration higher than permissible limits set by EU. Throughout
the study, DIA and MET presented 90.9% detection frequency in water samples followed
by ATR (87.3%), DEA and HA (81.8%) and TER (63.6%). The highest exceedance frequency
of the maximum permissible limit in wells was observed in well B5 followed by C1, C2, B1
and B3. The measured values of pesticide concentrations in all sampling sites are presented
by the box and whisker plot in Figure S1.
Table 4. Pesticides concentration from different European countries.
Reference Maximum Detection Frequency Samples > 0.1 µg/L
Concertation ( g/L) (%) (%) Year Country
µ
ATR (4.45) ATR (1.91)
ATR (0.38) MET (0.23) MET (1.91) MET (0.63)
TER (0.90)
Menchen et al. [28] TER (12.1) TER (2.81)
DIA (0.21) 2017 Spain
DIA (8.28) DIA (0.32)
DEA (0.12) DEA (5.73) DEA (0.32)
Meffe et al. [39] TER (29.05) not specied not specied 2014 Italy
Jurado et al. [40] ATR (3.45) MET (5.37)
TER (1.27) DEA (1.98) not specied not specied 2012 Spain
TER (1.42) TER (50) TER (15)
Hernández et al. [41] DIA (0.46) DEA DEA DIA (72) DIA (35) 2008 Spain
(0.40) DEA (35) DEA (8)
Int. J. Environ. Res. Public Health 2022, 19, 8877 8 of 16
Table 4. Cont.
Reference Maximum Detection Frequency Samples > 0.1 µg/L
Concertation ( g/L) (%) (%) Year Country
µ
ATR (0.37) ATR (4)
Sanchez-Gonzalez MET (100) ATR (4)
et al. [24] MET (0.55) TER (0.34) TER (70) MET (48) TER (36) 2013 Spain
DEA (0.34) DEA (8) DEA (4)
ATR (30) ATR (5)
Sanchez-Gonzalez ATR (0.19) MET (0.05) MET (25) TER (55) MET (0)
et al. [24] TER (1.89) DEA (0.08) TER (25) 2013 Portugal
DEA (26) DEA (0)
ATR (0.23) ATR (94.6)
MET (0.068) MET (38.8)
Korosa et al. [27] TER (0.03) TER (574) not specied 2016 Slovenia
DIA (0.02) DIA (17.9)
DEA (0.1) DEA (98.2)
ATR (0.2) ATR (12.5)
Lapworth et al. [42] DIA (0.1) DIA (9.6) not specied 2015 England
DEA (0.16) DEA (20)
ATR (0.69) ATR (73)
Lapworth et al. [42] DIA (0.47) DIA (60) not specied 2015 France
DEA (0.13) DEA (47)
The maximum concentrations detected in this study are within the range of concentra-
tions detected in groundwater samples at the European level, indicating that the established
herbicide residues are an international issue. Menchen et al. [28], recorded the maximum
concentrations for ATR (0.38 µg/L), MET (0.23 µg/L), DEA (0.12 µg/L), DIA (0.21 µg/L)
and TER (0.90 µg/L). According to Meffe et al. [39], the maximum concentrations for TER in
Italian groundwater was 29.05 µg/L. Considerable higher maximum concentrations were
found in Spanish groundwater by Jurado et al. [40], for ATR (3.45 µg/L), MET (5.37 µg/L),
DEA (1.98 µg/L) and TER (1.27 µg/L). Hernandez et al. [41] found that DIA was the most
frequent detected compound (72%), followed by TER (50%), with maximum concentrations
1.42 µg/L for DEA, 0.40 µg/L for DIA and 0.46 µg/L for TER. Moreover, a third Spanish
study in agricultural areas showed maximum concentration 0.33 µg/L for ATR, 0.37 µg/L
for DEA, 0.34 µg/L for TER and 0.55 µg/L for MET with detection frequency ranged from
4% (DEA) to 68% (MET). The same study presented results from Portuguese groundwater
in agricultural areas, too. TER had the highest concentration (1.88 µg/L) with frequency
detection reached 56%, followed by ATR (0.19 µg/L) and detection frequency 25%. DEA
and MET concentration were lower than 0.1 µg/L [24]. According to Korosa et al. [27],
in groundwater samples from Slovenia ATR and DEA were detected at concentrations
up to 0.228µg/L and 0.10 µg/L and their frequency of detection was 94.6% and 98.2%,
respectively. In another study conducted in United Kingdom and France, the highest con-
centrations in British groundwaters for ATR, DIA, and DEA were 0.20, 0.10 and 0.16 µg/L,
respectively, while the highest concentrations were lower than 0.1 µg/L, in France [42].
Table 4 presents the respective data of similar monitoring studies.
3.2. Historical Vulnerability of the Transboundary Aquifer to Contamination by Pesticide Residues
The fact that target compounds reached concentrations above the quality standard
values for drinking water indicates that studies made during pesticides registration process
are not always complying with the results from monitoring studies. It is estimated that less
than 1% of the pesticides applied reach the target pest and the remaining distributed to var-
ious environmental compartments including groundwater bodies [43]. In a previous study
was found that waters of that site constitute an aquatic mixture with different residence
times and various leaching mechanisms are involved to the pollution of groundwater [44].
Int. J. Environ. Res. Public Health 2022, 19, 8877 9 of 16
Similarly to the results obtained 15 to 19 years ago extreme concentrations were observed
in this study, indicating the presence of point source pollution sites nearby the studied wells.
Target compounds had beenmonitored previously (between 1999–2003), at the same locations,
before atrazine ban in EU [2]. Moreover, a similar study was conducted between 2010–2012
(data not shown), confirming the occurrence of ATR, DEA, DIA and MET (provided by
the Greek Ministry of Agricultural Development). In order to have a better perspective on
pollution temporal trends, the data of this study were compared with those of 1999–2003.
Fifteen to nineteen years ago MET had been detected at least once in 63 % of the wells
followed by ATR (61%), DEA (50%), alachlor (47%) and DIA (34%). According to Vryzas
et al. [2], maximum concentrations for ATR (1.48 µg/L), DEA (0.76 µg/L), DIA (0.07 µg/L)
and MET (1.54 µg/L) had been detected at the same drinking water wells sampled in this
study and considerable higher pesticide concentrations were detected in shallow groundwater
from experimental boreholes. This study confirms previously reported data on adsorption,
degradation and leaching of selected pesticides [2,31,44–46]. Vulnerability of the aquifer to
pollution depend on the land uses, soil properties, geological characteristics of the unsaturated
zone, the hydraulic properties, the depth of the vadose zone and the leaching potential or
physicochemical properties of the contaminant.
According to previous studies focused on this area, ATR degraded faster than MET in
all soils of the vadoze zone and the biotransformation rates of both compounds decreased
as the soil depth increased. Hence, the chronic presence of ATR in eld is indicated by
the higher biotransformation rate of ATR in soil taken from the middle of a studied eld
in comparison with soil sampled from the eld margins [2]. The major metabolites of
ATR and MET were found at higher concentrations in the 10–20 cm layers of all soil cores
studied 0–110 cm below ground surface. However, the enhanced biodegradation rate of
ATR in these soils is not enough to prevent the contamination of groundwater bodies. Our
results have been observed by other studies, too. According to McMahon et al. [47], Kolpin
et al. [48] and Steele et al. [49] degradation rates of triazine parent compounds are slower
than their transport rates in groundwater. Moreover, Vonberg et al. [25] and Jablonowski
et al. [50] conducted a solid samples analysis contaminated with atrazine from a lysimeter
and agricultural eld, respectively, reporting the persistence of the parent compound for
over 20 years after its last application, followed by possible leaching.
Adsorption studies of ATR, DEA, DIA, HA and MET were also conducted in soils
from ve different depths (i.e., 0–10, 10–20, 20–40, 40–80 and 90–110 cm below ground
surface). The present study revealed that when pseudo-equilibrium stage reached, the
amount of the adsorbed compounds accounted only for 10, 14, 27, 43 and 94% of the initial
amount of DEA, DIA, ATR, MET and HA, respectively, spiked to the soils. According to
this study, it was expected that more than 57 and 73% of the applied dose of MET and ATR,
respectively, to be desorbed into the soil water and be available for leaching to deeper soil
layers [45].
In addition, the low adsorption capacity of ATR and MET within soil profile of the
studied area, proved that the preferential flow is a major pesticide leaching mechanism in this
area since pollutants can reach the saturated zone of the aquifer through preferential flow
paths (shrinkage of the clay minerals, plant roots and earthworms forming burrows) without
going through chromatographic flow within the unsaturated zone and thereby circumventing
the degradation processes [46]. Studies on the apparent age of the studied aquifers shown
that the residence time of groundwater bodies ranged from 1.2 to 50 years [2].
The leaching mechanisms prevailed in this area has been also studied in an extensive
four-year eld experiment focused on soil water samples taken from 0–25, 35, 60, 100 and
160 cm below ground surface [46]. According to this study, MET, ATR, DEA and DIA
were detected in more than 67% of the total soil water samples. The main conclusion
of this study was that the corn-applied herbicides have been leached below the surface
soil via macropore-dominated pathways in less than one month after their application.
Agricultural practices (application of pesticides and sprinkler irrigation) used in this area,
soil structure and hydrogeological conditions increase the leaching potential of pesticides
Int. J. Environ. Res. Public Health 2022, 19, 8877 10 of 16
in the studied area. It is worth notice that alachlor, another banned herbicide, with very
limited half-life period (DT50eld = 14 days) had been detected in soil water of the studied
area at concentrations greater than 0.1 mg/L up to 40 months after its application.
Irrigation is usually carried out by self-propelled sprinkler irrigation systems or basin
irrigation systems multiple times in summer period. These types of irrigation system
provide high volumes of high-pressure water, which, in combination with rainfall, can
exacerbate the phenomenon of leaching [46]. Moreover, Nouma et al. [51] mentioned
that basin irrigation systems can favor pesticides leaching to groundwaters, too. As
recommend by Vryzas, et al. [46], the late pesticide application, use of drip instead of
sprinkler irrigation and delayed rst irrigation seem to be the major management actions
according to good agricultural practice that prevent pesticide leaching to groundwater in a
semiarid Mediterranean region. The limited spatial and temporal variation of concentration
levels observed in studied wells indicates a continuous load of the aquifer with the target
compounds. The continuous use of high amounts of atrazine for more than 30 years was
enough to contaminate the soil and aquifer and to be detected with its metabolites in
groundwater 15 years after its last use (2004). However, illegal applications cannot be
excluded since the studied area is 20 km from Turkish and Bulgarian borders and illegal
trade of banned pesticides had been observed.
The variability and seasonality of temperature and rainfall impact signicantly on the
fate of pesticides within soil zone. Along the study, the temperatures were ranged between
5.3 and 39.9 ◦C, reaching extremely high values. The vapor pressures of pesticides can be
increased as the temperature increases. In this study, pesticides have low vapor pressures
(Table 2) and therefore volatilization could not cause losses, except for DEA. Moreover, high
rainfall values were observed in May and June, 48.6 and 59 mm, respectively (Figure 2).
Heavy rainfall could induce the remobilization of organic pollutants adsorbed in soil
or sediments, especially lipophilic compounds such as ATR, TER and MET. Moreover,
high rainfall intensities can cause overow events and increase the frequency of leaching
phenomenon, which can also be more rapid under rainy conditions [52,53].
Precipitation (mm) Monthly average temperature (°C)
Monthly maximum temeprature (°C) Monthly minimum temperature (°C)
Meteorological station locaction
Latitude: 41° 30' 11.02" N
Longitude: 26° 31' 46.99" E
50 120
40 100
30
80
20
60
10
40
0
-10 20
-20 0
Figure 2. Meteorological data during the sampling period.
The MET and ATR effectiveness against corn weeds and the limited available herbi-
cides resulted their extensive use during the period of 1980–2005. ATR withdrawal brings
Temperatute (°C)
Precipitation (mm)
Int. J. Environ. Res. Public Health 2022, 19, 8877 11 of 16
out the TER as the most used herbicide, until nowadays. Application rates are similar,
ranged from 600 to 1200, 900 to 1800 and 860 to 1200 gr/ha for ATR, MET and TER, respec-
tively. The cropping system and major crops has been gradually changed from 2005 till
now. However, eld crops are still the major crops in the area and the irrigation practices
are the same that were used 20–40 years ago. TER applied by farmers in agricultural area
of Ardas valley as a pre-emergence herbicide for maize, cotton and beet cultivations in
April, replacing the banned ATR. The extended treatment period of TER coincides with the
signicant rainfall period in the studied area. The use of a basic measure also identies
TER as a moderate leachers: in fact, TER has a GUS (groundwater ubiquity score) score of
2.19, indicating that it is a leacher [54].
In laboratory investigations with various top-soils, the degradation of [14C] TER was
examined to determine which soil features would enhance metabolite production. After a
45-day incubation period, the concentration of TER dropped by 30%, while desethylter-
buthylazine was generated at the same time. In different soils, the TER half-life ranged from
88 to 116 days. In addition, a research team hypothesized that TER is more readily absorbed
by soil than atrazine, which could shield the molecule against biodegradation [55].
Commercial plant protection products bentazone, terbuthylazine and metolachlor
were used to investigate the degradation and leaching of bentazone, TER and S-metolachlor,
as well as their metabolites applied to a weighable, monolithic, high precision lysimeter
with a loamy, sandy soil. Bentazone decomposed faster in soil than TER and S-metolachlor,
but TER metabolization after the second application resulted in higher formation of de-
sethylterbuthylazine and TER hydroxylation. On day 12, the greatest concentration of TER
(310 g/kg) was found while the topsoil contained 16 g/kg of terbuthylazine on day 150,
indicating leaching losses [56].
3.3. DEA to ATR Ratio
The DEA to ATR ratio (DAR) has been used to categorize point and non-point source
pollution of groundwater and, in order to, characterize the degradation and transport of
ATR in response to its metabolite DEA. This ratio can give us an indication of the major
leaching mechanisms contribute to the pollution of groundwater and the capacity of the
unsaturated zone to biodegrade ATR to DEA. During the transport of atrazine through
chromatographic ow within the biological more active unsaturated zone it could be
metabolized in signicant amounts by microorganisms to DEA [2,57,58]. In such cases the
DAR would have values higher than 0.4, or even close to 1.0. In contrary, when atrazine
bypasses the vadose and enters the saturated zone through preferential ow the contact
time between atrazine and soil microbial community could be shorter and, therefore, the
DAR ratio would be less than 0.4. The DAR ratio can provide information about atrazine
leaching behavior based on the fact that atrazine represents a closer adsorption capacity
to DEA than to HA in spite of HA was found as the main metabolite of atrazine at same
area. In addition, this soil can adsorb higher amount of atrazine than DEA. Therefore,
DEA can be leached faster than atrazine through chromatographic or preferential ow [46].
The calculated DAR in this study was found to be higher than one in some cases, and
lower than one in most samples (Table 5), indicating that contamination in some cases
comes from diffuse sources but most probably the bound atrazine was gradually desorbed
from the soil matrix to the soil water and moved to groundwater through preferential
ow [25,46,59]. Although DAR values can be used to characterize the predominant leaching
mechanisms in the studied aquifer, the different types of wells (experimental boreholes,
drinking water wells and irrigation wells) used in this study and the respective differences
in construction techniques restrict the estimation of the various mechanisms involved in the
leaching processes.
Int. J. Environ. Res. Public Health 2022, 19, 8877 12 of 16
Table 5. Percentage (%) of samples with DAR value higher than 1.
Sampling Site Percentage (%)
A1 50
A2 25
A3 50
A4 50
B1 0
B2 0
B3 80
B4 50
B5 0
C1 40
C2 25
Our results are in agreement with those of Vryzas et al. [44], conducted in the same
area 15–19 years ago, who found similar DAR values few months after the application
of atrazine. Overall, atrazine’s degradation products showed higher concentrations than
did the parent compound. DIA exhibits a large range of concentrations varying between
0.01 µg/L and 2.91 µg/L. According to biotransformation studies conducted in the soil
prole of the studied area HA was the most frequently detected metabolite and with the
highest concentrations. The second most frequently detected degradation product in soil
was DEA, followed by rare DIA detections [2]. The overwhelming majority of soil water
samples with DEA presence, showed DEA had greater concentrations than DIA and the
ratio values CDEA/CDIA reached 33 [51]. DEA (50% of groundwater samples) was more
frequently detected than DIA (34% of groundwater samples) in an extensive groundwater
monitoring program conducted in the same area 15–19 years ago [2]. Contrary to previous
reported data, in this study, atrazine and its metabolites were detected with equal frequency
of detection.
3.4. Human Health Risk Assessment
An extended discussion was preceded related to the presence, occurrence and distribu-
tion reasons of target pesticides at studied area. Results on human health risk assessment
are presented in Table 6. Although, the HQ values for individual pesticide did not exceed
the value 1, the estimated non-carcinogenic risk for children was higher, when compared
to adults. The HQ values for mean pesticides concertation were ranged between 0.0171 to
0.1913 for adults and between 0.0393 to 0.5752 for children. The highest mean values are
reported to metolachlor and the lowest to atrazine. The highest HQ values were determined
in drinking water well close to Rizia namely, 0.2507 and 0.7817 for adults and children,
respectively. Similar HQ values for atrazine and metolachlor in surface water were reported
by Papadakis et al. [4], in a Greek study. The risk level for TER was low with HQ values
lower than 0.6.
The sum of HQ values did not reach the unity in all studied wells. The greatest
cumulative potential risk was determined in the Rizia well with values 0.2836 and 0.8299
for adults and children, respectively. The lowest potential risk has the Elia well, with values
lower than 0.4. Consequently, according to the acute risk assessment, the studied drinking
water wells are characterized as safe.
Oppositely, the carcinogenic risk assessment showed high values. In all cases, ATR R
values were higher than the parametric one of 1 × 10−6 recommended by USEPA, for both
age groups, showing that the local population were under carcinogenic risk (Table 6). The
water consumption through the Fylakio well presents the highest risk, while the Arzos well
was the lowest. The R values are ranged between 0.0002–0.0018 for adults and 0.0012–0.0181
for children. Previous study conducted in Greece, indicated high carcinogenic risk only for
children [4].
Int. J. Environ. Res. Public Health 2022, 19, 8877 13 of 16
Table 6. HQ and R indexes of pesticides through drinking water consumption, pumped by drinking wells.
Rizia (B1) Fylakio (B2) Elia (B3) Arzos (B4) Kastanies (B5)
Index Adult Child Adult Child Adult Child Adult Child Adult Child
HQ a
m 0.0422 0.1262 0.0684 0.2162 0.0171 0.0393 0.0184 0.0416 0.0515 0.1563
HQ b
h 0.0895 0.2916 0.2305 0.7839 0.0225 0.0548 0.0205 0.0509 0.0737 0.2333
ATR R c
m 0.0003 0.0029 0.0005 0.0050 0.0001 0.0009 0.0001 0.0010 0.0004 0.0036
R d
h 0.0007 0.0067 0.0018 0.0181 0.0002 0.0013 0.0002 0.0012 0.0006 0.0054
HQm 0.1913 0.5752 0.1342 0.3757 0.0751 0.1692 0.0821 0.1941 0.1432 0.4063
MET HQh 0.2507 0.7817 0.2502 0.7818 0.0985 0.2505 0.1206 0.3254 0.2238 0.6881
HQm 0.0501 0.1235 0.0391 0.0787 0.0501 0.1233 0.0402 0.0901 0.0512 0.1303
TER HQh 0.0672 0.1833 0.0459 0.1070 0.0758 0.2136 0.0481 0.1172 0.1619 0.5132
HQ SUM HQi 0.2836 0.8299 0.3058 0.6779 0.1403 0.3318 0.1407 0.3258 0.2459 0.6929
a HQm hazard quotient (mean concentration), b HQh hazard quotient (highest concentration), c Rm carcinogenic
risk (mean concentration) and d Rh carcinogenic risk (highest concentration).
4. Conclusions
All pesticides were detected in both shallow and deep ground-water bodies (experi-
mental boreholes, drinking or irrigation water wells). DIA and MET presented the highest
detection frequency in water samples, while TER and DIA showed the highest exceedance
frequency of the EU permissible limit. Perennially, these herbicides were used in a variety
weed-sensitive cultivations, including wheat, beet, cotton, maize and sunower. The type
of crops grown in a region largely determines the types of pesticides that were used, which
in turn affects the residues of pesticides that are typically found in the groundwaters of
studied region. Moreover, illegal used of banned pesticides cannot be excluded from a trans-
boundary area. Despite agricultural use of atrazine has been banned in Greece for more
than 18 years ago, atrazine and its metabolites residues are still detected in groundwater of
the region, indicating their high persistence in saturated zone. The repeated application
of studied pesticides could lead to enhanced biodegradation, as previously reported in
the studied area, but the remaining amounts of bound residues was gradually desorbed
from the soil matrix to the soil water and moved to groundwater through preferential
or chromatographic ow. Furthermore, the detection of extreme concentrations suggests
the presence of occasional point-sources pollution. However diffuse sources cannot be
excluded. These observations were conrmed by DAR ratios and the frequency of detection
of parent compounds and their respective metabolites, suggesting multi-mixed leaching.
The drinking water consumption for local people is safe considering the acute risk assess-
ment. However, the atrazine R values suggested high carcinogenic risk. We suppose that
EU regulatory agencies could benet from the linking of monitoring data with probabilistic
human models in order to propose efcient pollution management methods.
Supplementary Materials: The following supporting information can be downloaded at: https://
www.mdpi.com/article/10.3390/ijerph19148877/s1, Figure S1: Box-whisker plots of concentrations
of pesticides in sampling points: (a) atrazine, (b) DIA, (c) DEA, (d) HA, (e) terbuthylazine and
(f) metolachlor. The caps at the end of each box indicate the extreme values (minimum andmaximum),
the box is dened by the lower and upper quartiles, and the line inside the box denotes the median
value. The pesticide concentrations below the LOQs are considered as zero.
Author Contributions: P.P., C.A., A.F.-C. and Z.V. conceived and planned the experiments, P.P. and
C.A. made the sampling, P.P., M.S.R., G.P.-R. and M.P.-V. made the extractions and instrumental
analysis. P.P., Z.V., M.S.R., G.D.G., A.P.C. and A.F.-C. wrote the manuscript. All authors have read
and agreed to the published version of the manuscript.
Funding: This work was supported by European Union’s Horizon 2020 research and innovation
programme under the Marie Skłodowska-Curie grant agreement No. 690618 KNOWPEC (Knowledge
for pesticide control).
Institutional Review Board Statement: Not applicable.
Int. J. Environ. Res. Public Health 2022, 19, 8877 14 of 16
Informed Consent Statement: Not applicable.
Data Availability Statement: The datasets used and/or analyzed during the current study are
available from the corresponding author on reasonable request.
Conicts of Interest: The authors declare no conict of interest. The article reects only the author’s
view and the Agency is not responsible for any use that may be made of the information it contains.
References
1. Affum, A.O.; Acquaah, S.O.; Osae, S.D.; Kwaansa-Ansah, E. Distribution and risk assessment of banned and other current-use
pesticides in surface and groundwaters consumed in an agricultural catchment dominated by cocoa crops in the Ankobra Basin,
Ghana. Sci. Total Environ. 2018, 633, 630–640. [CrossRef] [PubMed]
2. Vryzas, Z.; Papadakis, E.N.; Vassiliou, G.; Papadopoulou-Mourkidou, E. Occurrence of pesticide in transboundary aquifers of
North-eastern Greece. Sci. Total Environ. 2012, 441, 41–48. [CrossRef]
3. Drouin, G.; Droz, B.; Leresche, F.; Payraudeau, S.; Masbou, J.; Imfeld, G. Direct and indirect photodegradation of atrazine and
S-metolachlor in agriculturally impacted surface water and associated C and N isotope fractionation. Environ. Sci. Process. Impacts
2021, 23, 1791–1802. [CrossRef]
4. Papadakis, N.E.; Vryzas, Z.; Kotopoulou, A.; Kintzikoglou, K.; Makris, C.K.; Papadopoulou-Mourkidou, E. A pesticide monitoring
survey in rivers and lakes of northern Greece and its human and ecotoxicological risk assessment. Ecotoxicol. Environ. Saf. 2015,
116, 1–9. [CrossRef]
5. Singh, S.; Kumar, V.; Chauhan, A.; Datta, S.; Wani, A.B.; Singh, N.; Singh, J. Toxicity, degradation and analysis of the herbicide
atrazine. Environ. Chem. Lett. 2017, 16, 211–237. [CrossRef]
6. Carazo-Rojas, E.; Perez Rojas, G.; Perez-Villanueva, M.; Chinchilla-Soto, C.; Chin-Pampillo, J.S.; Aguilar-Mora, P.; Alpizar-Marin,
M.; Masis-Mora, M.; Rodriguez-Rodriguez, C.E.; Vryzas, Z. Pesticide monitoring and ecotoxicological risk assessment in surface
water bodies and sediments of a tropical agro-ecosystem. Environ. Pollut. 2018, 241, 800–809. [CrossRef] [PubMed]
7. Syafrudin, M.; Kristanti, R.A.; Yuniarto, A.; Hadibarata, T.; Rhee, J.; Al-onazi, W.A.; Algarni, T.S.; Almarri, A.H.; Al-Mohaimeed,
A.M. Pesticides in Drinking Water—A Review. Int. J. Environ. Res. 2021, 18, 468. [CrossRef]
8. Tudi, M.; Daniel Ruan, H.; Wang, L.; Lyu, J.; Sadler, R.; Connell, D.; Chu, C.; Phung, D.T. Agriculture Development, Pesticide
Application and Its Impact on the Environment. Int. J. Environ. Res. 2021, 18, 1112. [CrossRef]
9. Hasegawa, S.; Sakayori, T. Monitoring of Matrix Flow and Bypass Flow through the Subsoil in a Volcanic Ash Soil. Soil Sci. Plant
Nutr. 2000, 46, 661–671. [CrossRef]
10. Milan, M.; Ferrero, A.; Fogliatto, S.; Piano, S.; Vidotto, F. Leaching of S-metolachlor, terbuthylazine, desethyl-terbuthylazine,
mesotrione, ufenacet, isoxautole, and diketonitrile in eld lysimeters as affected by the time elapsed between spraying and
rst leaching event. J. Environ. Sci. Health B 2015, 50, 851–886. [CrossRef]
11. Bakaraki Turan, N.; Tuğba Zaman, B.; Selali Chormey, D.; Onkal Engin, G.; Bakırdere, S. Atrazine: FromDetection to Remediation—
AMinireview. Anal. Lett. 2021, 55, 411–426. [CrossRef]
12. Directive 2006/118/EC; Protection of Groundwater against Pollution and Deterioration. European Parliament and Council: Brussels,
Belgium, 2006; Volume 372, pp. 19–31.
13. Directive 98/83/EC; Quality of Water Intended for Human Consumption. European Parliament and Council: Brussels, Belgium,
1998; Volume 330, pp. 32–54.
14. Directive 2000/60/EC; Establishing a Framework for Community Action in the Field of Water Policy. European Parliament and
Council: Brussels, Belgium, 2000; p. 327.
15. Directive 2008/105/EC; European Parliament and of the Council on Environmental Quality Standards in the Field of Water Policy.
European Parliament and Council: Brussels, Belgium, 2008; Volume 348, pp. 84–97.
16. Stradtman, S.C.; Freeman, J.L. Mechanisms of Neurotoxicity Associated with Exposure to the Herbicide Atrazine. Toxics 2021, 9,
207. [CrossRef]
17. Yang, L.; Li, H.; Zhang, Y.; Jiao, N. Environmental risk assessment of triazine herbicides in the Bohai Sea and the Yellow Sea and
their toxicity to phytoplankton at environmental concentrations. Environ. Int. 2019, 133, 105175. [CrossRef] [PubMed]
18. USEPA. Reregistration Eligibility Decision (RED) Terbuthylazine; USEPA: Washington, DC, USA, 1995.
19. Mercadante, R.; Polledri, E.; Giavin, E.; Menegola, E.; Bertazzi, P.A.; Fustinoni, S. Terbuthylazine in hair as a biomarker of
exposure. Toxicol. Lett. 2012, 210, 169–173. [CrossRef]
20. USEPA. Health Effects Assessment for Asbestos. EPA, 1995. Re-Registeration Eligibility (RED) Facts: Metolachlor. EPA-738-F-95-007.EPA
Prevention, Herbicides, and Toxic Substances; USEPA: Washington, DC, USA, 2009.
21. Thorpe, N.; Shirmohammadi, A. Herbicides and Nitrates in Groundwater of Marylandand Childhood Cancers: A Geographic
Information Systems Approach. J. Environ. Sci. Health C 2005, 23, 261–278. [CrossRef] [PubMed]
22. Rusiecki, J.A.; Hou, L.; Lee, W.J.; Blair, A.; Dosemeci, M.; Lubin, J.H.; Bonner, M.; Samanic, C.; Hoppin, J.A.; Sandler, D.P.; et al.
Cancer incidence among pesticide applicators exposed to metolachlor in the Agricultural Health Study. Int. J. Cancer 2006, 118,
3118–3123. [CrossRef] [PubMed]
23. Papastergiou, A.; Papadopoulou-Mourkidou, E. Occurrence and spatial and temporal distribution of pesticide residues in
groundwater of major corn-growing areas of Greece (1996–1997). Environ. Sci. Technol. 2001, 35, 63–69. [CrossRef]
Int. J. Environ. Res. Public Health 2022, 19, 8877 15 of 16
24. Sanchez-Gonzalez, S.; Pose-Juan, E.; Herrero-Hernandez, E.; Alvarez-Martin, A.; Sanchez-Martin, M.J.; Rodriguez-Cruz, S.
Pesticide residues in groundwaters and soils of agricultural areas in the Agueda River Basin from Spain and Portugal. Int. J.
Environ. Anal. Chem. 2013, 93, 1585–1601. [CrossRef]
25. Vonberg, D.; Vanderborght, J.; Cremer, N.; Pütz, T.; Herbst, M.; Vereecken, H. 20 years of long-term atrazine monitoring in a
shallow aquifer in western Germany. Water Res. 2014, 50, 294–306. [CrossRef]
26. Szekacs, A.; Mortl, M.; Darvas, B. Monitoring Pesticide Residues in Surface and Ground Water in Hungary: Surveys in 1990–2015.
J. Chem. 2015, 2015, 717948. [CrossRef]
27. Korosa, A.; Auersperger, P.; Mali, N. Determination of micro-organic contaminants in groundwater (Maribor, Slovenia). Sci. Total
Environ. 2016, 571, 1419–1431. [CrossRef] [PubMed]
28. Menchen, A.; De las Heras, J.; Gómez Alday, J. Pesticide contamination in groundwater bodies in the Júcar River European Union
Pilot Basin (SE Spain). Environ. Monit. Assess. 2017, 189, 146. [CrossRef] [PubMed]
29. PPDB (Pesticide Properties Data Base). Pesticides General Information; University of Hertfordshire: Hateld, UK, 2016; Available
online: https://sitem.herts.ac.uk/aeru/ppdb/en/Reports/1362.htm (accessed on 1 March 2022).
30. Papadakis, E.M.; Papadopoulou-Mourkidou, E. LC-UV determination of atrazine and its principal conversion products in soli
after combined microwave-assisted and solid-phase extraction. Int. J. Environ. Anal. Chem. 2006, 86, 573–582. [CrossRef]
31. Vryzas, Z.; Vassiliou, G.; Alexoudis, C.; Papadopoulou-Mourkidou, E. Spatial and temporal distribution of pesticide residues in
surface waters in north-eastern Greece. Water Res. 2009, 43, 1–10. [CrossRef]
32. Kim, H.H.; Lim, Y.W.; Yang, J.Y.; Shin, D.C.; Ham, H.S.; Choi, B.S.; Lee, J.Y. Health risk assessment of exposure to chlorpyrifos and
dichlorvos in children at childcare facilities. Sci. Total Environ. 2013, 444, 441–450. [CrossRef]
33. Muhammad, S.; Shah, M.T.; Khan, S. Health risk assessment of heavy metals and their source apportionment in drinking water of
Kohistan region, northern Pakistan. Microchem. J. 2011, 98, 334–343. [CrossRef]
34. Ali, N.; Kalsoom; Khan, S.; Ihsanullah; ur Rahman, I.; Muhammad, S. Human Health Risk Assessment Through Consumption of
Organophosphate Pesticide Contaminated Water of Peshawar Basin, Pakistan. Expos. Health 2018, 10, 259–272. [CrossRef]
35. USEPA. Denitions and General Principles for Exposure Assessment: Guidelines for Exposure Assessment; Ofce of Pesticide Programs:
Washington, DC, USA, 1999.
36. IRIS (Integrated Risk Information System). Oral Chronic Reference Dose Integrate Risk Information System Database; Toxicity
and Chemical Specic Factor Database. Available online: www.epa.gov/iris (accessed on 2 September 2021).
37. FOOTPRINT. The FOOTPRINT Pesticide Properties Data Base. Database Collated by (FP6-SSP-022704). Available online:
http://sitem.herts.ac.uk/aeru/footprint/en/index.htm (accessed on 2 September 2021).
38. Mas, L.I.; Aparicio, V.C.; De Gerónimo, E.; Costa, J.L. Pesticides in water sources used for human consumption in the semiarid
region of Argentina. SN Appl. Sci. 2020, 2, 691. [CrossRef]
39. Meffe, R.; Bustamante, I. Emerging organic contaminants in surface water and groundwater: A rst overview of the situation in
Italy. Sci. Total Environ. 2014, 481, 280–295. [CrossRef]
40. Jurado, A.; Vázquez-Suñé, E.; Carrera, J.; López de Alda, M.; Pujades, E.; Barceló, D. Emerging organic contaminants in
groundwater in Spain: A review of sources, recent occurrence and fate in a European context. Sci. Total Environ. 2012, 440, 82–94.
[CrossRef]
41. Hernández, F.; Marín, J.M.; Pozo, O.J.; Sancho, J.V.; López, F.J.; Morell, I. Pesticides residues and transformation products in
groundwater from a Spanish agricultural region on the Mediterranean Coast. J. Environ. Anal. Chem. 2008, 88, 409–424. [CrossRef]
42. Lapworth, D.J.; Baran, D.; Stuart, M.E.; Manamsa, K.; Talbot, J. Persistent and emerging micro-organic contaminats in Chalk
groundwater of England and France. Environ. Pollut. 2015, 203, 214–225. [CrossRef] [PubMed]
43. Pimentel, D.; Levitan, L. Pesticides: Amounts applied and amounts reaching pests. BioScience 1986, 36, 86–91. [CrossRef]
44. Vryzas, Z.; Papadakis, E.; Oriakli, K.; Moysiadis, T.P.; Papadopoulou-Mourkidou, E. Biotransformation of atrazine andmetolachlor
within soil prole and changes in microbial communities. Chemosphere 2012, 89, 1330–1338. [CrossRef]
45. Vryzas, Z.; Papadopoulou-Mourkidou, E.; Soulios, G.; Prodromou, K. Kinetics and adsorption of metolachlor and atrazine and
the conversion products (deethylatrazine, deisopropylatrazine, hydroxyatrazine) in the soil prole of a river basin. Eur. J. Soil Sci.
2007, 58, 1186–1199. [CrossRef]
46. Vryzas, Z.; Papadakis, E.N.; Papadpoulou-Mourkidou, E. Leaching of Br-, metolachlor, alachlor, atrazine, deethylatrazine and
deisopropylatrazine in clayey vadoze zone: A eld scale experiment in north-east Greece. Water Res. 2012, 46, 1979–1989.
[CrossRef] [PubMed]
47. McMahon, P.B.; Chapelle, F.H.; Jagucki, M.L. Atrazine mineralization potential of alluvial-aquifer sediments under aerobic
conditions. Environ. Sci. Technol. 1992, 26, 1556–1559. [CrossRef]
48. Kolpin, D.W.; Kalkhoff, S.J.; Goolsby, D.A.; Sneck-Fahner, D.A.; Thurman, E.M. Occurrence of selected herbicides and herbicide
degradation products in Iowa’s groundwater, 1995. Ground Water 1997, 35, 679–688. [CrossRef]
49. Steele, G.V.; Johnson, H.M.; Sandstrom, M.W.; Capel, P.D.; Barbash, J.E. Occurrence and fate of pesticides in four contrasting
agricultural settings in the United States. J. Environ. Qual. 2008, 37, 1116–1132. [CrossRef]
50. Jablonowski, N.D.; Köppchen, S.; Hofmann, D.; Schäffer, A.; Burauel, P. Persistence of 14C-labeled atrazine and its residues in a
eld lysimeter soil after 22 years. Environ. Pollut. 2009, 157, 2126–2131. [CrossRef]
51. Nouma, B.B.; Rezig, M.; Bahrouni, H. Best Irrigation Practices Designed for Pesticides Use to Reduce Environmental Impact on
Groundwater Resource in the Tunisian Context. J. Agric. Sci. 2016, 8, 142–152. [CrossRef]
Int. J. Environ. Res. Public Health 2022, 19, 8877 16 of 16
52. Bloomeld, J.P.; Williams, R.J.; Gooddy, D.C.; Cape, J.N.; Guha, P. Impacts of climate change on the fate and behaviour of
pesticides in surface and groundwater—A UK perspective. Sci. Total Environ. 2006, 369, 163–177. [CrossRef] [PubMed]
53. Park, W.-P.; Chang, K.-M.; Hyun, H.-N.; Boo, K.-H.; Koo, B.-J. Sorption and leaching characteristics of pesticides in volcanic ash
soils of Jeju Island, Korea. Appl. Biol. Chem. 2020, 63, 71. [CrossRef]
54. Bozzo, S.; Azimonti, G.; Villa, S.; Di Guardo, A.; Finizio, A. Spatial and temporal trend of groundwater contamination from
terbuthylazine and desethylterbuthylazine in the Lombardy Region (Italy). J. Environ. Qual. 2003, 32, 1089–1098. [CrossRef]
55. Guzzella, L.; Rullo, S.; Pozzoni, F.; Giuliano, G. Studies on Mobility and Degradation Pathways of Terbuthylazine Using
Lysimeters on a Field Scale. Environ. Sci. Process. Impacts 2013, 15, 366. [CrossRef] [PubMed]
56. Schuhmann, A.; Klammler, G.; Weiss, S.; Gans, O.; Fank, J.; Haberhauer, G.; Gerzabek, M.H. Degradation and leaching of
bentazone, terbuthylazine and S-metolachlor and some of their metabolites: A long-term lysimeter experiment. Plant Soil Environ.
2019, 65, 273–281. [CrossRef]
57. Adams, C.D.; Thurman, E.M. Formation and transport of deethylatrazine in the soil and vadose zone. J. Environ. Qual. 1991, 20,
540–547. [CrossRef]
58. Goolsby, D.A.; Thurman, E.M.; Pomes, M.L.; Meyer, M.T.; Battaglin, W.A. Herbicides and their metabolites in rainfall: Origin,
transport, and deposition patterns across the Midwestern and northeastern United States, 1990–1991. Environ. Sci. Technol. 1997,
31, 1325–1333. [CrossRef]
59. Hildebrandt, A.; Guillamón, M.; Lacorte, S.; Tauler, R.; Barceló, D. Impact of pesticides used inagriculture and vineyards to
surface and groundwater quality (North Spain). Water Res. 2008, 42, 3315–3326. [CrossRef]