area that is generally flat with
rolling hills and no obvious topographic features to de-
lineate its boundaries. The North Eastern Aquifer (NEA)
is formed from two main aquifer basins: The Shallow
Aquifer (from the Eocene age) and the Deep Aquifer (of
the Turonian-Upper Cenomanian age), separated by a
chalk layer of Senonain age. Based on the exposure of the
formations; the natural recharge is estimated to be around
130 MCM/year. The yearly abstraction estimated from the
associated wells is estimated to be about 27 MCM/year [5].
Groundwater quality in the Basin has shown some dete-
rioration over time, primarily due to surface contamina-
tion from wastewater and unsustainable agricultural
practices [6].
The WAB lies under the western part of the West
Bank Mountains underlying and flows to the west to-
wards the Mediterranean Sea. WAB is formed of two
main aquifers: the Upper Aquifer (Turonian-Upper Ceno-
manian age) and the Lower Aquifer (Lower Cenomanian
to Upper Albian age) separated by a marly aquitard
called the Yatta formation. The average thickness of
these aquifers ranges from 600 to 900 meters. Based on
the exposure of the geologic formations, the average annual
natural recharge for the Basin is around 335 - 370 MCM/year
[5].
4.2. Soil and Groundwater Pollution
Soils in the studied areas can mainly be classified as be-
ing Grumusols, and Pale Randzisan Terra Rossa and
Brown Rendzinas which are degraded as a result of many
factors including erosion, acidification and salinization
due to both anthropogenic (man-made) and non-anthro-
pogenic (natural) causes. The main natural cause is the
change in climatic conditions in the area(rainfall and tem-
perature), while man-made causes include socio-economic
Table 1. The international standards guideline and their instrumentation detection limit.
Parameters* Detection limits* Benchmark Regulator
Iron (Fe) 100 1000 WHO***
Cobalt (Co) 2 - WHO***
Cadmium (Cd) 10 3 WHO***
Lead (Pb) 10 10 WHO***
Zinc (Zn) 100 3000 WHO***
Chromium (Cr) 50 50 WHO***
Copper (Cu) 50 2000 WHO***
2,4 D 1 100 WHO***
MC 250 37 EPA-2**
Paraquat 50 150 WHO***
Atrazine 10 2 WHO***
*Unit in µg/l for the analyst. * *EPA (Environmental Protection Agency). ***WHO, 1998 (World He alth Organization).
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Groundwater Pollution Due to Pesticides and Heavy Metals in North West Bank431
Figure 1. Representative sampling points in the study area in Tulkarem and Jenin. The numbers are representing sampling
points.
factors, existing land uses and use of organic and inor-
ganic material in agricultural activity. Soil and ground-
water pollution is caused mainly b y agricultural practices
(notably the use of inorganic fertilizers and pesticides),
localized industrial activities (organic pollutants, heavy
metals), and inadequate or improper disposal of waste-
water and solid waste (including hazardous materials).
Pesticides are used in large quantities in Tulkarem and
Jenin [7]. These include chemicals imported and used
illegally, despite of long-standing international bans. For
example, soil sterilizing with methyl bromide is officially
banned, yet still practiced extensively in greenhouse
farming in Tulkarem and Jenin [7]. Groundwater con-
tamination depends on land use, local soil and geological
conditions. Since limestone outcro ps over the study area,
this facilitates the penetration of substances increasing
the aquifer’s vulnerability to contamination.
4.3. Climate
The climate of Tulkarem and Jenin as the rest of the
West Bank is affected by diverse ranges in topography
and altitude and is influenced by the Mediterranean en-
vironment which is characterized by long, hot, dry sum-
mers and short, cool, rainy winters. The average annual
precipitation in Tulkarem is estimated at 642 mm for the
period extending from 1952 to 2006 with a total of rainy
days ranging fro m 57 to 75 during 1995- 2006. The aver-
age annual maximum relative humidity values was esti-
mated to be about 75.9% in February while the lowest
value was in May at about 62% during 1995-2004. The
average annual maximum temperature was recorded to
be 22.3˚C and the mean annual minimum temperature
was 15.6˚C [8]. The average annual precipitation in Jenin
is 528 mm. The average yearly temperature is 27.1˚C,
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Groundwater Pollution Due to Pesticides and Heavy Metals in North West Bank
432
while the average minimum temperature is 13.5˚C and
the mean annual humidity is 67.2% during the winter
[9].
4.4. Geography and Geology
Tulkarem has a highly varying topography; with the
highest point at 500 m above sea level and the lowest at
40 m above sea level. The same goes for Jenin that has a
peak height of 750 m above sea level while the lowest
level is at 90 m above sea level. In terms of geology, the
majority of the Tulkarem and Jenin area is rocky mainly
comprised of carbonate sediment such as limestone, car-
bonate, chalk and marl. The geological rock age forma-
tions range from Cretaceous to Quaternary.
5. Discussion
5.1. MCPP, 2, 4-D and Atrazine
Environmental pollution arises through inadequate dis-
posal practices of various amounts of organic compounds
from agricultural activities that are applied and distrib-
uted in the general environment through the air, water
and soil, particularly during periods of rain, high winds,
or high temperature. 2, 4-D and its derivatives character-
ized by alkali or amine salts used as agricultural herbi-
cides against broad-leaf weeds in cereal crops as well as
on pastures and lawns are fairly rapidly broken down by
hydrolysis, photolysis, and by biological action. Persis-
tence or accumulation of 2, 4-D residues from normal
use is occasionally possible, mainly under dry or cold
conditions where there is little biological activity [10].
Consequently leading to the contamination of water
sources used for irrigation and drinking purposes.
There is no data about the environmental fate of the
impurities present in 2, 4-D herbicides. In general, 2, 4-D
residues in surface water were found to be less than 0.1 µg/l.
This is not unexpected, according to the relatively rapid
biodegradation of 2, 4 D in the environment [11].
Atrazine is an herbicide used for weed control which is
largely used in the study area with different commercial
names. Atrazine is adsorbed or dissolved with organic
matters which result in enhanced aqueous solubility
therefore, enhancing the mobility of Atrazine. Most of
the decrease in Atrazine concentration in the root zone
over time could be attributed to leaching and degradation
during the study period [12]. The concentrations of 2,
4-D and Atrazine in the collected samples are less than
the permissible guidelines set at 100 and 2 µg/l respec-
tively (Figure 2) and had different distribution trends.
The shallower water table in the wells of Jenin compared
to that in Tulkarem increases the risk of using the water
for domestic purposes especially without monitoring
organic compounds.
Results showed that most of the analyzed samples did
not contain Parquet or contain amounts less than the in-
ter national guideline standard (100 µg/l acco rding to EPA
-2). Results for MCPP, considered as an indicator for the
most common herbici des, are shown i n Figure 3.
Results of MCPP concentrations revealed that there is
a direct relation between depth and the presence of or-
ganic accumulation in the tested wells, this supports and
correlates the presence of nitrate and its incremental to
MCPP in acid form in high amounts.
5.2. Heavy Metals
Analyses of heavy metals are rarely done in the West
Bank for monitoring purposes. The result for Pb was
greater than the WHO guideline [10] set at 10 µg/l.
While Cr and Cd were found in concentrations around
the WHO guideline of 50 and 3 µg/l r espectively. The Cr
and Pb concentrations show fluctuations above and be-
low the WHO standard [10] (Table 1), hence; both are
considered as sources of pollution caused by industry and
arbitrary dumping sites that deteriorates the groundwater
(Figure 4).
Concentrations of heavy metals varied both spatially
and temporally and were distributed in a way in which it
is more crucial in the wells in Jenin compared to those in
Tulkarem (Figure 5), since the depths to the water table
are shallower compared to those in Tulkarem.
Figure 2. The concentrations of 2, 4-D and Atrazine in the
study area.
Figure 3. The concentrations of MCPP in the groundwater
wells in the study are a .
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Groundwater Pollution Due to Pesticides and Heavy Metals in North West Bank433
Figure 4. The concentrations of the trace elements in Tul-
karem area.
Figure 5. The concentrations of the trace elements in Jenin
area.
5.3. Nitrate, Potassium and Depth
The results illustrate that there is a direct relation be-
tween the depth and the concentration of nitrate due to
practices and activities on the ground mainly being the
use of fertilizers. Nitrate levels in the groundwater are
found to be above the WHO guideline values due to fer-
tilizers making the sources unfit for drinking purposes
(i.e. >50 mg/liter). The same goes for potassium incre-
mental and accumulation. In most of the cases the tested
sources bacterial pollution was absent further justifying
that the nitrate and potassium incremental are due to the
extensive use of fertilizers. The accumulation of organic
substances and heavy metals w ere verified by comparing
between nitrate and potassium incremental results and
well depths as in Figure 6.
Figure 6. Variations of NO3, K versus depth in Tulkarem
and Jenin groundwater wells.
6. Conclusions
Analysis results indicate that the nitrate and potassium
increment in shallow wells makes the sources unfit for
domestic consumption. This is mainly d ue to agricultural
activities and the use of fertilizers. Results revealed that
Parquet was not found in the tested wells since it has
only been introduced and used very recently. Heavy met-
als were also investigated in the two areas; cationic pa-
rameters can be easily exchanged in the complex com-
pounds as aligned. In Tulkarem there was no significant
pollution from the trace elements mainly Pb 90%, Cd
20% and Cr 35%. On the other hand, in Jenin about 85%
of the tested samples were polluted with Pb. The effects
of these pollutants on human health due to the low bio-
degradability and accumulations of organics and trace
compounds must also be determined.
7. Recommendations
It is recommended to control and restrict the agricultural
and industrial activity in both areas in order to prevent
the leachate from reaching the groundwater. Pesticides
and mainly those contai ning a hal ogen-carbon bon d should
be investigated in the future. It is also recommended to
initiate a pilot scale study for chlorinated water and con-
trolling the organic indicators of Total Organic Carbon
(TOC) and Dissolved Organic Carbon (DOC). Raising
the awareness of all relevant institutions working in the
fields of environmental pollution and discussing water
treatment issues for the future is strongly recommended.
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