7 soil pollution risk -...

7 SOIL POLLUTION RISK

RESULTS AND DISCUSSION

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7.1 MAIN CHEMICAL POLLUTANTS

7.1.1 PHOSPHORUS

Phosphorus is an essential element for plant growth. Plants must have P to

conduct photosynthesis. It is one of major three fertilizer nutrients. Although the

majority of soil P is not soluble for plant absorption, Barber (1984) showed that

the total amount of phosphorus in top soil as an average of 1000 kg ha-1

is not

large compared to annual crop removals of 10 to 40 kg ha-1

. This is especially true

since a large fraction of the phosphorus present is in a mineral form not readily

available for absorption by the plant. Egashira et al. (2003) studied the surface

layers of 13 agricultural soils collected from locations differing in the parent rock.

They found that total P concentration ranged from 251 to 1334 mg kg-1

and was

most highly and significantly correlated with the organic P concentration

percentage. Organic (P) percentage from the total (P) varied considerably with the

soils from 11 to 70%. Amer and Abou-El Roos (1975) showed that total P in

Egyptian soils ranged from 870 to 1781 mg kg-1

in clay loam soils, about 722 mg

kg-1

in (sandy loam) soils and from 337 to 481 mg kg-1

in sandy soils. References

indicate that total phosphorus in soils varies considerably, the high values being

associated with heavy texture alluvial soils. According to Awaga (1989) the total

phosphorus content in Egyptian soils ranged between 270 to 1360 ppm expressed

as profile means, which ranged from 300 to 1050 mg kg-1

in alluvial soils and from

270 to 340 mg kg-1

in sandy soils and was about 680 mg kg-1

in calcareous soils.

Saarela (2003), found that total P ranged from 1066 - 1870 mg kg-1

. In addition,

Egashira et al. (2003) showed that total phosphorus in Ganges flood plains ranged

from 257 to 726 mg kg-1

soil. Important phosphorus levels have been reported in

Qarun and Wadi El-Rayan lake sediments Abdel-Satar and Sayed (2010) and water

(Omar et al., 2013).

Phosphate retention is considered the main problem of phosphorus found in

Egyptian soils especially in El-Fayoum soils. These soils have some physical and

chemical characteristics such as low P-availability high pH, high CaCO3 content,

high soluble calcium cations, fine clay and amount of Al and Fe oxides. Some of

these variables enhance P-fixation (retention) which transfer available-P to

unavailable forms. As a result of P-retention reaction in Egyptian soils, total-P

amounts in such soils become very high, whereas the available amount remains

very low and lies within the deficient range. Available amount of phosphorus is

related to soil characteristics as pH, CaCO3 content, clay mineralogy, sesquioxides,

and calcium concentration in soil solution. Any of these factors or combinations

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thereof may be linked to transformations of P from available to fixed form,

unavailable to plants. The concentration of total-P in the dry season varied wildly,

which was much higher than those in the wet and normal season (Song et al.,

2013). Phosphorus (P) is a crucial element in the eutrophication of the Great Lakes

(Van Bochove et al., 2011), and high levels of phosphate promote over-production

of algae and aquatic weeds. However that may be, many of us have

misconceptions as to the origin of pollutants phosphates, and many homeowners

unwittingly contribute to the problem. In 1976, the international Pollution from

Land Use Activities Reference Group (PLUARG) estimated that about 24% of all P

entering the entire Great Lakes basin came from the agricultural land on both

Canadian and US sides (PLUARG 1978).

7.1.2 NITRATES

The inorganic forms of soil nitrogen include ammonium (NH4+), nitrate (NO3

-),

nitrous oxide (N2O), nitric oxide (NO) and elemental nitrogen (N2). The last form of

nitrogen is inert except for its utilization by rhizobia and other nitrogen-fixing

microorganisms. From the standpoint of soil fertility the NH4+, NO2

-, and NO3

-

forms are of greatest importance; N2O and NO are also important in a negative

way, for they represent forms of nitrogen that are lost through denitrification. The

ammonium and nitrate forms arise either from the normal aerobic decomposition

of soil organic matter or from the addition to the soil of various commercial

fertilizers, these three forms usually represent from 2 to 5% of the total soil

nitrogen (Tisdale et al., 1985). Soil N occurs as inorganic or organic N, with 95% or

more of total N in surface soils present as organic N, (Tisdale et al., 1990).

According Sutapa et al. (2006) waste amendments increase the total N content of

soil (Muir et al., 1973) found that NO3-N concentration in soil is positively

correlated with the source of N-fertilizer, and livestock density but negatively

correlated with soil pH and depth. (Paramasivam et al., 2000) studied the

transport of NO3-N and NH4-N in fine sand, after heavy addition of liquid fertilizer

containing ammonium nitrate. They reported that both NO3-N and NH4-N are

transported quite rapidly (within 3 days). The concentrations of NO3-N in El-

Fayoum district soils ranged from 0.03 to 40.22 within the surface layer (0-30) and

from 0.01 to 33.2 in subsoil (30-60) with a mean 14.88 mg kg-1

within the top 60

cm (Hamdi, 2007). Acording to Xue Ying et al., 2013 the tributaries of the Taizi

River (China) were seriously contaminated by NH3-N, with 83.8%, 100% and 100%

of the sampling sites exceeding the fifth level in the dry season, wet season and

normal season, respectively.


155

The excess of nitrogen lead to overstimulation of growth of aquatic plants and

algae. These organisms, in turn, can clog water intakes, use up dissolved oxygen

as they decompose, and block light to deeper waters. Also the excess nitrogen in

water can harm persons where, too much nitrogen, as nitrate, in drinking water

can be harmful to young infants or young cattle. Excessive nitrate can result in

restriction of oxygen transport in the bloodstream. Infants under the age of 4

months lack the enzyme necessary to correct this condition "blue baby

syndrome". In parts of Eastern Europe where groundwater is contaminated with

50-100 ppm of nitrate, pregnant women and children under 1 year of age are

supplied with bottled water (USGS, 2014)6.

Nitrate contamination is one of the most problems that affect Spain where more

than 50% of the Spanish population lives in areas whose rivers are polluted by

nitrates. This compound in water cause problems in the digestive system and in

the long term, could lead to increased risk of cancer in these organs. Over ten

million of Spanish persons are exposed to high concentrations of nitrates,

considering that, in cities such as Madrid, much of the water comes from aquifers

and, if they are close to highly fertilized agricultural areas, the presence of nitrates

is a threat almost certain(FVS, 2011)7.

7.1.3 HEAVY METALS AND PESTICIDES

“Heavy metals” designates not only heavy metals, but also a group of metal and

metalloid elements that show similar behaviors in the soil system and trophic

chains. Originally, only some metals denser than iron (Cd, Hg and Pb) were

included in this definition, but, currently, many elements are considered heavy

metals, although the term is not fully accepted by IUPAC, and some alternative

names (e.g., toxic metal) have been suggested, for which there is no consensus.

However, elements that may represent a serious environmental problem

(including some light metals as Be or Al) are commonly referred to as "heavy

metals". Heavy metal contamination is an important problem, causing serious

alterations to the environment and adversely affecting human health (Souza etal.,

6 http://water.usgs.gov/edu/nitrogen.html

7 https://www.vidasostenible.org

CHAPTER 7

156

2014). Heavy metals have long been a component of some agricultural pesticides

that are sprayed on croplands and eventually end up in rivers, lakes and coastal

waters. They are also found in high concentrations in sewage sludge, some

fertilizers and industrial waste. The macro fauna and microorganisms may absorb

heavy metals from the surrounding water or from their food. When absorbed,

heavy metals tend to accumulate in certain tissues and organs, rather than being

uniformly distributed in the body, causing numerous harmful effects on

organisms. Heavy metals often accumulate in the nervous system and brain,

causing lesions, behavioral disturbances and diverse neurological problems. Heavy

metals may also impair growth, cause malformations of the body, damage organs,

or disrupt the immune system. Due to limitations in the allowed amounts of water

from the Nile, vast areas of agricultural lands in El-Fayoum Province are irrigated

with water from mixing stations that mix fresh Nile water and old drainage water

that lead to increasing concentrations of heavy metals in soil and water.

Glenn et al. (1995) studied how the amount of sludge applied to soil influences

the composition of the soil solution. Because the movement of heavy metals

within soils is mainly in the solution phase, chemical factors that control the

distribution of metals between the solid and solution phase influence the mobility

of heavy metals. Some of the soil chemical reactions controlling mobility of heavy

metals and phosphorus are in fact adsorption/ desorption processes. Determining

the metal and phosphorus sorption properties of soil gives a good indication of

the mobility and, therefore, the bioavailability of these elements. Hence, an

understanding of sorption properties is essential when determining loading rates

of sludge-borne heavy metals and phosphorus to soils that will have minimal

impact on the environment.

The concentrations of heavy metals, nitrate and total soluble salt in such mixed

water depends mainly on the mixing ratio and how well the water is mixed.

Detailed long-term monitoring of the concentrations of heavy metals

concentrations, nitrates and total soluble salts is the only way to distinguish

between non-contaminated, contaminated and polluted soils

Concentrations of total Cd in El-Fayoum District soils greatly exceeded the

maximum permissible limits listed by several developed countries. The

concentrations of total Ni in soils slightly exceeded the maximum critical limits

recommended by developed countries. Although the concentrations of total Pb in

soils all over the area of El-Fayoum District were generally below the maximum


157

permissible limits, there is evidence of Pb concentration increases in few spots

particularly in soil surface near main roads and urban areas (Hamdi, 2007).

Total and DTPA extractable heavy metals indicated that the surface layer (0-30)

cm of El-Fayoum District soils generally contained greater concentrations of both

total and DTPA extractable Cd, Ni and Pb in comparison with those in subsoil (30-

60 cm) with some exceptions in several sites. The concentrations of total Cd, Pb

and Ni in top soils were 2.16, 1.87 and 2.88 times those of the layer (30-60cm)

respectively. Corresponding ratios of DTPA extractable metals were 2.27, 1.4 and

1.74 respectively. This was due to atmospheric depositions, applied commercial

fertilizers (phosphates in particular) pesticides, manures, town refuse and maybe

discharge of domestic sewage (Hamdi, 2007).

7.1.4 CRITICAL THRESHOLD OF SOIL CONTAMINANTS

The concentration of trace elements in the soil is increasingly becoming an issue

of global concern, especially as soils constitute a crucial component of rural and

urban environments, and it can be considered a very important "ecological

crossroad" in the landscape (USDA, 2001). Although some are essential for growth

and reproduction, trace elements are toxic for living organisms at excessive

concentrations. Deficiencies in these essential elements or micronutrients can

lead to disease and even death of organisms. Some essential trace elements are

Co, Cr, Cu, Mn, Mo, Ni, Se, and Zn. Others, as Ag, As, Ba, Cd, Hg, Pb and Sb may

also have negative impacts. The most important heavy metals with regards to

potential hazards and occurrence in contaminated soils are As, Cd, Cr, Hg, Pb, and

Zn (Alloway, 1995).

The accumulation of heavy metals in agricultural soils is of increasing concern due

to the food safety issues and potential health risks as well as its detrimental

effects on soil ecosystems. These metals have peculiar characteristics including:

� Their concentration in soils does not decay with time.

� They can be necessary or beneficial to plants at certain levels, but toxic

when exceeding specific thresholds.

� They are always present at a background level of non-anthropogenic

origin, as their input in soils may be related to weathering of parent rocks

and pedogenesis.

� They often occur as cations which strongly interact with the soil matrix.

Consequently, heavy metals in soils can become mobile as a result of

changing environmental conditions.

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158

The major external source of heavy metals in soils is usually pollution, caused by

anthropogenic activities, such as metal mining, smelting, and processing (Rosman

et al., 1993).

In addition to aerial sources of trace pollutants, fertilizers, pesticides, and all

sewage-derived materials contribute to increase the trace element pool in soils.

The mobilization of heavy metals from smelter and mine spoil by transport with

seepage waters or by windblown dust may also be an important source of soil

contamination in some industrial regions. The variability of trace element

concentrations in materials used in agriculture is presented in Table 7-1.

High concentration of trace elements in soils may be derived from various

sources, including anthropogenic pollution, weathering of natural high

background rocks, and metal deposits (Asaah and Abimbola, 2006).

The reference values for heavy metals in soils for agricultural soils, with relation to

the soil vulnerability classes are shown in Table 7-2.

Contamination of soil with heavy metals can occur because of anthropogenic

activities such as manufacturing, mining, smelting procedures, and agriculture, as

well as natural activities (Navarro et al., 2008).

Table 7-1. Main agricultural sources of trace element contamination in soils (ppm DW).

Adapted from Kabata-Pendias (2001).

Element Manure

(ppm)

N- fertilizers

(ppm)

P- fertilizers

(ppm)

Sewage sludge

(ppm)

Pesticides (%)

As 3–25 2–120 2–1200 2–26 22–60

B 0.3–0.6 6 5–115 15–1000 -

Be - - - 4–13 -

Cd 0.3–0.8 0.05–8.5 0.1–170 2–1500 -

Co 0.3–24 5–12 1–12 2–260 -

Cr 5.2–55 3–19 66–245 20–40600 -

Cu 2–60 1–15 1–300 50–3300 12–50

F 7 82–212 8500–38000 2–740 18–45

Hg 0.09–0.2 0.3–3 0.01–1.2 0.1-55 0.8–42

Mo 0.05–3 1–7 0.1–60 1–40 -

Ni 7.8–30 7–38 7–38 16–5300 -

Pb 6.6–15 2–1450 7–225 50–3000 60

Sb - - - - -

Se 2.4 - 0.5-25 2–10 -

Zn 15–250 1–42 50–1450 700–49000 1.3–25


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Table 7-2. Reference values for heavy metals agricultural soils with relation to the soil

vulnerability classes (V1-V4) (ppm DW). Source: MIMAM (2000).

Element V1 V2 V3 V4

As 35 30 25 20

Cd 3 1.5 1 0.5

Co 50 40 30 20

Cr 250 200 125 70

Cu 140 100 50 20

Hg 1.5 1 0.5 0.4

Mo 5 10 15 30

Ni 85 65 45 25

Pb 300 100 70 50

Zn 300 200 150 70

Table 7-3. Maximum admissible concentrations (MAC) of trace elements in agricultural

soils proposed or given in the directives in various countries. and year (ppm DW).

Source: Adapted from Kabata-Pendias (2001) and MIMAM (2000).

Element Spain

2000

Austria

1977

Poland

1993

Russia

1986

UK

1987

Germany

1992

EU

1986

US

1993

As - 50 30 2 10 - - -

B - 100 - - - - - -

Be - 10 10 - - - - -

Cd 1-3 5 1-3 - 3-15 1.5 1-3 20

Co - 50 50 - - - - -

Cr - 100 50-80 0.05 - 100 50-150 1500

Cu 50-220 100 30-70 23 50 60 50-140 750

F 500 - - - - - -

Hg 1-1.5 5 5 2.1 - 1 1-1.5 8

Mo 10 10 - - - - -

Ni 30-112 100 30-75 35 20 50 30-75 210

Pb 50-300 100 70-150 20 500-2000 100 50-300 150

Sb - - 10 - - - - -

Se - 10 10 - - - - -

V - - 150 150 - - - -

Zn 150-450 300 100-300 110 130 200 150-300 1400

Kabata-Pendias (2001), reported that long-term use of inorganic phosphate

fertilizers adds substantially to the natural levels of Cd in soils, while other

CHAPTER 7

160

elements such as As, Cr and Pb do not increase significantly. Effects of sewage

sludge applications on soil composition are especially of great environmental

concern and have been the subject of many studies and much legislation. Advisory

standards and guidelines for safe addition of trace elements in sewage sludge to

land is still in the stages of experiment however, several authors have suggested

threshold values for the maximum admissible concentration of trace elements in

soils for specific countries (Table 7-3).

7.2 SOIL POLLUTION RISK IN ANDALUSIA UNDER CLIMATE CHANGE SCENARIOS

7.2.1 PHOSPHORUS CONTAMINATION RISK

Results show, there are small differences among contamination vulnerabilities

classes of phosphorus under future hypothetical climatic scenarios (Table 7-4). A

positive effect of climate change is observed in the soil type JA06-Typic

Haploxerepts, where the attainable risk varied from V4rl subclass in the current

scenario to be V3r subclass in the future climate scenarios. Net positive effects of

climate change with respect to P were also observed in MA04-Typic Haploxerolls,

SE02-Typic Rhodoxeralfs, SE09-Typic Xerofluvents and SE05-Typic Fluvaquents. In

general, the total area that has a positive effect represents about 7.0% of the

studied area.

Table 7-4. Spatial distribution (area, km2 and %) of vulnerability classes (V1, none; V2,

low; V3, moderate; V4, high; V5, extreme) by phosphorus contamination risk under

current and future climate scenarios. The number of limitation factors is shown between

parentheses.

Land

vulnerability

classes

1960-2000 2040 2070 2100

km2 %

km

2 %

km

2 %

km

2 %

V1 13650 15.6 14648 16.7 14648 16.7 14648 16.7

V2 13857 15.8 11955 13.6 11955 13.6 11955 13.6

V3 2157 2.5 0 0.0 0 0.0 0 0.0

V3(1) 21280 24.3 26211 29.9 26211 29.9 26211 29.9

V4 18834 21.5 19963 22.8 19963 22.8 19963 22.8

V4(1) 16489 18.8 14823 16.9 14823 16.9 14823 16.9

V4(2) 1333 1.5 0 0.0 0 0.0 0 0.0


161

Figure 7-1. Attainable and actual phosphorus contamination vulnerability under current

and future climate scenarios. Vulnerability class: V1, None; V2, Low; V3, Moderate; V4,

High; 5,Extreme. Limitation factors: r=Surface Run-off; l=Leaching Degree.

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V1

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Natural regions with negative climate change impact

Natural regions with positive climate change impact

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V3-/i

V4-/i

V5-/i

V5r/i



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V5r/i

V5rl/i

CHAPTER 7

162

On the other hand, negative impacts are expected under the projected climate

change scenarios, especially on JA08-Lithic Haprendolls and HU02-Lithic

Xerorthents (Figure 7-1). According to this, 3.5% of the study area shows a

negative impact, where the actual vulnerability class under future climate

scenarios is V5-/i instead of V4-/I under current climate conditions (Figure 7-1).

7.2.2 NITROGEN CONTAMINATION RISK

In the case of nitrogen contamination vulnerability, most positive impacts under

projected climate change scenarios (2040, 2070 and 2100) were found in JA06-

Typic Haploxerepts, where the attainable vulnerability class was V4ld and the

contamination risk decreased to V2r. In general, nitrogen contamination risk

decreased in approximately 19% of total area in Andalusia. CO04-Typic

Haploxerepts showed a negative impact under projected climate scenarios, with

variations only at subclass level (limiting factors), changing from V3c to V3cr

(attainable) and from V5c/j to V5cr/j (actual risk). Also, negative changes at

subclass level have been observed in JA08- Lithic Haprendolls: V2 to V2r

(attainable risk) and V4-/j to V4r/j (actual risk). In general, about 5% of the studied

area is expected to support negative impacts and the changes involved the

limiting factors in subclass level.

The area of N vulnerability changed between the current scenario and future

climate scenarios. But no changes among 2040, 2070 and 2100 climate changes

scenarios are expected.

Table 7-5. Total area (km2 and %) of vulnerability classes (V1, none; V2, low; V3,

moderate; V4, high; V5, extreme) by nitrogen contamination risk under current and

future climate scenarios. The number of limitation factors is shown between

parentheses.

Land

vulnerability

classes

1960-2000 2040 2070 2100

km2 %

km

2 %

km

2 % km

2 %

V1 12895 14.7 21937 25.0 21937 25.0 21937 25.0 V2 13954 15.9 4109 4.7 4109 4.7 4109 4.7

V2(1) 31065 35.5 38083 43.5 38083 43.5 38083 43.5

V3 1129 1.3 - - - - - -

V3(1) 13521 15.4 11240 12.8 11240 12.8 11240 12.8

V3(2) 13703 15.6 12231 14.0 12231 14.0 12231 14.0

V4(2) 1333 1.5 - - - - - -


163

Figure 7-2. Attainable and actual nitrogen contamination vulnerability under current and

future climate scenarios. Vulnerability class: V1, none; V2, low; V3, moderate; V4, high;

5, extreme. Limitation factors: r, surface runoff; l, leaching degree; c, cation exchange

capacity; d, denitrification.

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V5 -/ j

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V5 cr,dr,ld / j

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V3 -/ j

V4 -/ j

V4 c,d,r / j

V5 r / j

V5 cr, dr / j


CHAPTER 7

164

7.2.3 HEAVY METAL CONTAMINATION RISK

In the case of study heavy metal contamination vulnerability under the projected

climate change scenarios, about 15% of the studied area will have a positive effect

under different future climate scenarios. High variation between classes is

expected in JA06-Typic Haploxerepts, changing from V4rl to V3r (attainable risk)

and only subclass-level changes from V5rl/e to V5r/e (actual risk) (Figure 7-3).

About 2% of the studied area will have a negative impact, especially on JA08-

Lithic Haprendolls, where attainable risk increased from V2, current, to V3r in the

future climate scenarios, and actual risk increased from V4-/e, current, to V5r/e,

under future projected scenarios, as shown in Figure 7-3.

No variation among the different climate change scenarios (2040, 2070 and 2100)

is expected in spatial and temporal analysis (Figure 7-3 and Table 7-6) and,

generally, the amount of vulnerable areas will decrease under future scenarios in

compassion to the current climate scenario (Table 7-6).


moderate; V4, high; V5, extreme) by heavy metals contamination risk under current and

future climate scenarios. The number of limitation factors is shown between

parentheses.

Land vulnerability

classes

1960-2000 2040 2070 2100

km2 % km

2 % km

2 % km

2 %

V1 20030 22.9 24559 28.0 24559 28.0 24559 28.0 V2 9441 10.8 4109 4.7 4109 4.7 4109 4.7

V3 1129 1.3 - - - - - -

V3(1) 45108 51.5 54920 62.7 54920 62.7 54920 62.7

V4(1) 6547 7.5 - - - - - -

V4(2) 5345 6.1 4012 4.6 4012 4.6 4012 4.6


165

Figure 7-3. Attainable and actual heavy metals contamination vulnerability under

current and future climate scenarios. Vulnerability class: V1, none; V2, low; V3,

moderate; V4, high; 5, extreme. Limitation factors: r, surface runoff; l, leaching degree;

c, cation exchange capacity; d, denitrification.

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V1

V2

V3 c, d, r

V4 cr



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Climate scenario 2040, 2070 and 2100 (Actual risk)


V3 -/ e

V4 -/ e

V5 c, r, d / e

V5 cr / e



CHAPTER 7

166

7.2.4 PESTICIDES CONTAMINATION RISK

According to results, contamination risk by pesticides in the studied area is higher

than in the case of phosphorus, nitrogen and heavy metals. Only 9.0% of the study

area shows positive effects under different climate scenarios, while 17.0% of the

studied soils show negative climate change impacts. GR11-Aquic Xerofluvents and

JA01-Typic Rhodoxeralfs show the highest positive changes, with vulnerability

class decreasing under climate change scenarios. In JA01-Aquic Xerofluvents, the

risk class decreased from V4og to V3o (attainable vulnerability) and from V5og/e

to V4o/e (actual vulnerability class) (Figure 7-4).

CA03-Calcic Rhodoxeralfs show the highest negative impacts, with attainable

vulnerability increasing from V2r (current scenario) to V4r (future climate

scenarios). In addition, actual vulnerability increased from V4r/e, current scenario,

to V5r/e under different future scenarios 2040, 2070 and 2100 (Figure 7-4). As

shown in (Table 7-7), vulnerability classes are not expected to vary under the

different climate change scenarios. On the other hand, variations between current

and future scenarios have been observed.

Table 7-7. Total area (km2 and %) of vulnerability classes by pesticide contamination risk

under current and future climate scenarios (V1, none; V2, low; V3, moderate; V4, high;

V5, extreme). The number of limitation factors is shown between parentheses.

Land

vulnerability

classes

1960-2000 2040 2070 2100

km2 %

km

2 %

km

2 %

km2

%

V1 7022 8.0 6773 7.7 6773 7.7 6773 7.7 V2 7465 8.5 7714 8.8 7714 8.8 7714 8.8

V2(1) 2699 3.1 1054 1.2 1054 1.2 1054 1.2

V3(1) 24215 27.6 15460 17.6 15460 17.6 15460 17.6

V3(2) - 0.0 - - - - - -

V3(3) 1666 1.9 - - - - - -

V4 - 0.0 - - - - - -

V4(1) 19450 22.2 26746 30.5 26746 30.5 26746 30.5

V4(2) 15196 17.3 25245 28.8 26384 30.1 26384 30.1

V4(3) 9887 11.3 4608 5.3 3469 4.0 3469 4.0


167

Figure 7-4. Attainable and actual pesticides contamination vulnerability under current

and future climate scenarios. Vulnerability class: V1, none; V2, low; V3, moderate; V4,

high; V5, extreme. Limitation factors: r, surface runoff; l, leaching degree; c, cation

exchange capacity; d, denitrification; o, pesticides sorption; g, biodegradation.

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Climate scenario 2040, 2070 and 2100 (Attainable risk)


V1

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V4 rg, or

V4 org



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V2 -/ e

V4 -/ e

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V5 r / e

V5 og, or, rg / e

V5 lor, org / e

Pesticides contamination vulnerability (Actual risk)

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V2 - /e

V4 - /e

V4 o, r /e

V5 r /e

V5 or, rg /e

V5 org /e



CHAPTER 7

168

Figure 7-5. Total area and vulnerability classes of phosphorus, nitrogen, heavy metals

and pesticides contamination risk in different climate scenarios. Vulnerability class: V1,

none; V2, low; V3, moderate; V4, high; V5, extreme. Limitation factors: I, phosphate; j,

nitrogen.

Figure 7-5 shows the histogram of areas according to different vulnerability

classes of contamination risk by phosphorus, nitrogen, heavy metals and

pesticides under different climate scenarios. Results show that actual

contamination risk is higher than attainable risk, because of the impacts of soil

management practices (which include the addition of nitrogen, phosphorus

fertilizers and pesticides).

7.3 SOIL POLLUTION RISK IN EL-FAYOUM UNDER DIFFERENT MANAGEMENT

SCENARIOS

Pantanal outputs include vulnerability classes (land, management and field

vulnerability) for phosphorus, nitrogen, heavy metals and pesticides for different

soils, types of management and crops, including maize, beans, wheat and

sorghum (Table 7-8). Results show no differences for attainable vulnerability

under different management scenarios of wheat, maize, sorghum and bean,

Actual risk (Erosion)

V1 V2 V3 V4 V5

0

20

40

60

Vulnerability classes

V1 /i V2 /i V3 /i V4 /i V5 /i

0

20

40

60

Attainable risk (Phosphorus)

Actual risk (Phosphorus)

Area (x1000 km2)

V1 V2 V3 V4 V5

0

20

40

60Attainable risk (Nitrogen)

V1 /j V2 /j V3 /j V4 /j V5 /j 0

20

40

60Actual risk (Nitrogen)


Area (x1000 km2)

V1 V2 V3 V4 V5

0

20

40

60Attainable risk (Heavy metals)

V1 /e V2 /e V3 /e V4 /e V5 /e

0

20

40

60Actual risk (Heavy metals)

Area (x1000 km2)


V1 V2 V3 V4 V5

0

20

40

60

V1 /e V2 /e V3 /e V4 /e V5 /e

0

20

40

60


Area (x1000 km2)

Attainable risk (Pesticides)

Actual risk (Pesticides)

Current 2040 2070 2100


169

where the phosphorus vulnerability class was V1 in different soil units: Vertic

Torrifluvents (F-SU1), Typic Haplocalcids (F-SU2), Typic Torrifluvents (F-SU3), Typic

Haplosalids (F-SU5) and V2 in Typic Haplogypsids (F-SU4),Typic torripsamments (F-

SU6). On the other hand, vulnerability varied among the different crop

management, but all soil types showed the same vulnerability class. Attainable

vulnerability for phosphorus, nitrogen and heavy metals varied from V1 to V2 and

varied from V1 to V3 in the case of pesticides.

Management vulnerability was V3-V4 (phosphorus), V2-V4 (nitrogen), V4 (heavy

metals) and V2 (pesticides), under the different soil types and crop managements.

Field vulnerability represents the combination of attainable risk and management

risk and varies depending on soil unit and crop management. Results show that

contamination risk by different agents under maize, beans, wheat and sorghum

cultivations is generally limited by management practices and soil properties.

Table 7-8. Attainable, management and contamination vulnerability risks for wheat,

maize, sorghum and bean crops in El-Fayoum. Vulnerability class: V1, none; V2, low; V3,

moderate; V4, high. Contaminant type: P, phosphorus; N, nitrogen; H, heavy metals; X,

pesticides. Degradation factors: q, heavy metals ; I, phosphate ; j, nitrogen ; o, pesticide

sorption.

Crop Soil profile Attainable vulnerability Managment vulnerability Field vulnerability

P N H X P N H X P N H X

Wheat F-SU1 V1 V1 V1 V2 V3 V3 V4q V2 V2-/- V2-/- V3-/q V2-/-

F-SU2 V1 V1 V1 V2 V3 V3 V4q V2 V2-/- V2-/- V3-/q V2-/-


F-SU4 V2 V1 V1 V3o V3 V3 V4q V2 V4-/- V2-/- V3-/q V3o/-


F-SU6 V2 V2 V2 V3o V3 V3 V4q V2 V4-/- V4-/- V4-/- V3o/-

Maize F-SU1 V1 V1 V1 V2 V4i V4j V4q V2 V3-/i V3-/j V3-/q V2-/-

F-SU2 V1 V1 V1 V2 V4i V4j V4q V2 V3-/i V3-/j V3-/q V2-/-


F-SU4 V2 V1 V1 V3o V4i V4j V4q V2 V4-/i V3-/j V3-/q V3o/-


F-SU6 V2 V2 V2 V3o V4i V4j V4q V2 V4-/i V4-/j V4-/q V3o/-

Sorghum F-SU1 V1 V1 V1 V2 V3 V4j V4q V2 V2-/- V3-/j V3-/q V2-/-

F-SU2 V1 V1 V1 V2 V3 V4j V4q V2 V2-/- V3-/j V3-/q V2-/-

F-SU3 V2 V1 V1 V3o V3 V4j V4q V2 V4-/- V3-/j V3-/q V3o/-


F-SU5 V1 V1 V1 V1 V3 V4j V4q V2 V2-/- V3-/j V3-/q V1-/-


Bean F-SU1 V1 V1 V1 V2 V4i V2 V4q V2 V3-/i V1-/- V3-/q V2-/-

F-SU2 V1 V1 V1 V2 V4i V2 V4q V2 V3-/i V1-/- V3-/q V2-/-

F-SU3 V2 V1 V1 V3o V4i V2 V4q V2 V3-/i V1-/- V3-/q V1-/-

F-SU4 V2 V1 V1 V3o V4i V2 V4q V2 V4-/- V1-/- V3-/q V3o/-

F-SU5 V1 V1 V1 V1 V4i V2 V4q V2 V3-/i V1-/- V3-/q V1-/-

F-SU6 V2 V2 V2 V3o V4i V2 V4q V2 V4-/i V2-/- V4-/q V3o/-

CHAPTER 7

170

Table 7-9 shows the area corresponding to each vulnerability class (V1, V2, V3 and

V4), based on the evaluation of contamination risk of 46 representative soil

profiles from SDBm-El-Fayoum. The assessment was carried out for phosphorus,

nitrogen, heavy metals and pesticides under different management types of four

major crops (wheat, maize, sorghum and bean).

Phosphorus and nitrogen vulnerability classes under the different studied crops

and managements have the same distribution areas (Table 7-9). Table 7-10 shows

no variation among the distribution of vulnerability classes by heavy metals under

the different crops and types of management. Similarly, Table 7-11 shows no

variation among the distributions of vulnerability classes for pesticides under the

different crops and managements.


moderate; V4, high) of phosphorus and nitrogen under wheat, maize, sorghum and bean

crops.

Soil unit


V1-none

V2-low

V3-moderate

V4-high

km2 %

km

2 %

km

2 %

km

2 %

Wheat

F-SU1 0 0

506.7 66.7

0 0

253.3 33.3 F-SU2 42.1 10

0 0

0 0

378.9 90

F-SU3 0 0

0 0

80.6 57.1

60.4 42.9 F-SU4 0 0

29 33.3

0 0

58 66.6

F-SU5 0 0

58 100

0 0

0 0 F-SU6 0 0

0 0

0 0

26 100

Maize

F-SU1 0 0

0 0

506.7 66.7

253.3 33.3 F-SU2 42.1 10

0 0

0 0

378.9 90

F-SU3 0 0

0 0

80.6 57.1

60.4 42.9 F-SU4 0 0

0 0

29 33.3

58 66.6

F-SU5 0 0

0 0

58 100

0 0 F-SU6 0 0

0 0

0 0

26 100

Sorghum

F-SU1 0 0

506.7 66.7

0 0

253.3 33.3 F-SU2 42.1 10

0 0

0 0

378.9 90

F-SU3 0 0

80.6 57.1

0 0

60.4 42.9 F-SU4 0 0

29 33.3

0 0

58 66.6

F-SU5 0 0

58 100

0 0

0 0 F-SU6 0 0

0 0

0 0

26 100

Bean

F-SU1 0 0

0 0

464.4 61.1

295.6 38.9 F-SU2 42.1 10

0 0

0 0

378.9 90

F-SU3 0 0

0 0

80.6 57.1

60.4 42.9 F-SU4 0 0

0 0

29 33.3

58 66.6

F-SU5 0 0

0 0

58 100

0 0 F-SU6 0 0

0 0

0 0

26 100


171

The assessment of land degradation (contamination and erosion risk) has been

studied based on four scenarios of management and under wheat, sunflower and

olive. Table 7-12 shows the different practices between the four studied

scenarios.


moderate; V4, high) of heavy metals vulnerability classes under wheat, maize, sorghum

and bean management crops.

Soil unit V1 V2 V3 V4

km2 % km

2 % km

2 % km

2 %

F-SU1 0 0 0 0 760.0 100 0 0

F-SU2 0 0 0 0 378.9 90 42.1 10.0

F-SU3 0 0 0 0 141.0 100.0 0 0

F-SU4 0 0 0 0 87.0 100.0 0 0

F-SU5 0 0 0 0 58 100.0 0 0

F-SU6 0 0 0 0 6.5 25.0 19.5 75.0


moderate; V4, high) of pesticides vulnerability classes under wheat, maize, sorghum and

bean management crops.

Soil unit V1 V2 V3 V4

km2 % km

2 % km

2 % km

2 %

F-SU1 42.2 5.6 211.1 27.8 506.7 66.7 0 0

F-SU2 0.0 0 42.1 10.0 336.8 80.0 42.1 10.0

F-SU3 0.0 0 40.3 28.6 20.1 14.3 80.6 57.1

F-SU4 0.0 0 29.0 33.3 58.0 66.7 0 0

F-SU5 19.3 33.3 19.3 33.3 19.3 33.3 0 0

F-SU6 0 0 0 0 6.5 25.0 19.5 75.0

CHAPTER 7

172

Table 7-12. The different practices of the principles four management scenarios.

Practices Scenario 1 Scenario 2 Scenario 3 Scenario 4

Land use type None Arable, irrigated Arable, irrigated Arable, irrigated

Irrigation water

(mm)

11 714 1142 1427

Crop rotation Nill, grazing Winter summer,

crop

combination

Winter summer,

crop

combination

Winter summer,

crop

combination

Land use on slopes Yes Yes Yes Yes

Addition of P-

fertilizer

Nothing Controlled Excessive Excessive

Addition of N-

fertilizer

Nothing Controlled Excessive Excessive

Addition of animal

manure

No Yes Yes Yes

Addition of

industrial / urban

waste

No No Yes Yes

Season of

fertilization

Autumn/win

ter

Autumn/winter Autumn/winter Autumn/winter

Use of pesticides No Yes Yes Yes

Persistence of

pesticides

Nil Low, < 6 months Medium, 6-12

months

High, ˃ 12

months

Toxicity (LD50,

ppm)

Nil Low, >1001 Medium, 200-

1000

High,<200

Methods of

application of

pesticides

Nil Foliage Foliage Direct

Artificial drainage No Yes Yes Yes

Artificial ground

water

No No Yes Yes

Treatment of

residues

Nil, grazing Mulching,

ploughed in

Mulching,

ploughed in

Burning

Tillage Zero tillage Minimum tillage Mulch tillage Conventional

tillage

Depth of tillage Without

superficial

tillage

With superficial

tillage

With superficial

tillage

With superficial

tillage

Tillage method Nil Use of dick

cultivator

Use of dick

cultivator

Use of dick

cultivator

Row spacing (m) Nil 0.1 0.1 0.1

Soil conservation

techniques (water

erosion)

Nil Terracing Terracing Terracing

Soil conservation

techniques (wind

erosion)

Nil Nil Nil Nil


173

Table 7-13. Vulnerability classes of ccontamination under different management

scenarios for wheat, sunflower and olive in El-Fayoum. Contaminant type: P,

phosphorus; N, nitrogen; H, heavy metals; X, pesticides. Vulnerability classes: V1, none;

V2, low; V3, moderate; V4, high. Degradation factors: q, heavy metals; I, phosphate; j,

nitrogen; o, pesticide sorption.

Management

scenario

Wheat Sunflower Olive

P N H X P N H X P N H X

Scenario 1 V4i V4j V4q V4t V4i V4j V4q V4t V4e V4j V4q V4t

Scenario 2 V4i V2 V4q V3 V4i V4j V4q V2 V3 V4j V4q V3

Scenario 3 V3 V2 V4q V2 V3 V2 V4q V2 V2 V2 V2 V1

Scenario 4 V2e V2e V2e V2e V2e V2e V2e V2e V2e V2e V2e V2e

Table 7-13, shows that class of management vulnerability for wheat, sunflower

and olive crops decreases with water irrigation. When vulnerability to

contamination by nitrogen, heavy metals and pesticides, and to water and wind

erosion were considered, highest risks were observed under Scenario 1 (100%

water irrigation), while lowest risks were observed under Scenario 4 (no irrigation

and no cultivation, rainfed conditions). The vulnerability was analysed.

Attainable vulnerability by nitrogen and heavy metals show the same risk under

different crops and scenarios for each soil profile, varying between V1 (F-SU1, F-

SU2, F-SU3 and F-SU4) and V2 (F-SU6) (Table 7-14 to Table 7-16). Vulnerability to

pesticides was V1 (F-SU3 and F-SU5), V2 (F-SU1 and F-SU2) and V3 (F-SU4 and F-

SU6). Typic Haplogypsids (F-SU4) and Typic torripsamments (F-SU6) show the high

soil degradation risk (contamination and erosion). Under wheat (Table 7-14),

sunflower (Table 7-15) and olive (Table 7-16), the highest vulnerability classes for

contamination by phosphorus, nitrogen, heavy metals and pesticides and water

erosion were observed under scenario 1. These results are in agreement with

Abdel Kawy and Belal (2012), who stated that, under current irrigation policies,

heavy metals accumulation in the surface layer of cropped soils will go on

increasing due to the use of drainage water for irrigation. The lower vulnerability

classes were observed under scenario 4. In opposite, a high vulnerability for wind

erosion was observed under scenario 4.

These results are in agreement with Ali and Abdel Kawy (2013), who have

reported intense chemical degradation in EL-Fayoum soils. They suggested that

degradation risk and the actual hazard indicate that the human activities are not

CHAPTER 7

174

sufficient to overcome the degradation processes in the most of the depression.

The high variability of results suggests that soil information is a key issue for

adequate land use planning and risk assessment (Abd-Elmabod et al., 2010).

Table 7-14. Attainable and field vulnerability of contamination under different

management scenarios for wheat crop in El-Fayoum. Contaminant type: P, phosphorus;

N, nitrogen; H, heavy metals; X, pesticides. Vulnerability class V1, none; V2, low; V3,

moderate; V4, high. Degradation factors: q, heavy metals; I, phosphate; j, nitrogen; o,

pesticide sorption; t, pesticides.

Managment scenario Soil profile Attainable vulnerability Field vulnerability

P N H X P N H X

Scenario #1 F-SU1 V1 V1 V1 V2 V3-/i V3-/j V3-/q V4-/t

F-SU2 V1 V1 V1 V2 V3-/i V3-/j V3-/q V4-/t


F-SU4 V2 V1 V1 V3o V4-/i V3-/j V3-/q V5o/t


F-SU6 V2 V2 V2 V3o V4-/i V4-/j V4-/q V5o/e

Scenario #2 F-SU1 V1 V1 V1 V2 V3-/i V1-/- V3-/q V4-/-

F-SU2 V1 V1 V1 V2 V3-/i V1-/- V3-/q V4-/-

F-SU3 V1 V1 V1 V1 V3-/i V1-/- V3-/q V2-/-

F-SU4 V2 V1 V1 V3o V4-/i V1-/- V3-/q V4o/-

F-SU5 V1 V1 V1 V1 V3-/i V1-/- V3-/q V2-/-

F-SU6 V2 V2 V2 V3o V4-/i V2-/- V4-/q V4o/-

Scenario #3 F-SU1 V1 V1 V1 V2 V2-/- V1-/- V3-/q V2-/-

F-SU2 V1 V1 V1 V2 V2-/- V1-/- V3-/q V2-/-

F-SU3 V1 V1 V1 V1 V2-/- V1-/- V3-/q V1-/-

F-SU4 V2 V1 V1 V3o V4-/- V1-/- V3-/q V3o/-

F-SU5 V1 V1 V1 V1 V2-/- V1-/- V3-/q V1-/-

F-SU6 V2 V2 V2 V3o V4-/- V2-/- V4-/q V3o/-

Scenario #4 F-SU1 V1 V1 V1 V2 V1-/e V1-/e V1-/e V2-/e

F-SU2 V1 V1 V1 V2 V1-/e V1-/e V1-/e V2-/e


F-SU4 V2 V1 V1 V3o V2-/e V1-/e V1-/e V3o/e




175


management scenarios for sunflower crop in El-Fayoum. Abbreviations as in Table 7-14

(page 174).

Managment scenario Soil profile Attainable

vulnerability

Field vulnerability

P N H X P N H X

Scenario #1 F-SU1 V1 V1 V1 V2 V3-/i V3-/j V3-/q V4-/t






Scenario #2 F-SU1 V1 V1 V1 V2 V3-/i V3-/j V3-/q V2-/-

F-SU2 V1 V1 V1 V2 V3-/i V3-/j V3-/q V2-/-

F-SU3 V1 V1 V1 V1 V3-/i V3-/j V3-/q V1-/-

F-SU4 V2 V1 V1 V3o V4-/i V3-/j V3-/q V3o/-

F-SU5 V1 V1 V1 V1 V3-/i V3-/j V3-/q V1-/-

F-SU6 V2 V2 V2 V3o V4-/i V4-/j V4-/q V3o/-

Scenario #3 F-SU1 V1 V1 V1 V2 V2-/- V1-/- V3-/q V2-/-

F-SU2 V1 V1 V1 V2 V2-/- V1-/- V3-/q V2-/-

F-SU3 V1 V1 V1 V1 V2-/- V1-/- V3-/q V1-/-

F-SU4 V2 V1 V1 V3o V4-/- V1-/- V3-/q V3o/-

F-SU5 V1 V1 V1 V1 V2-/- V1-/- V3-/q V1-/-

F-SU6 V2 V2 V2 V3o V4-/- V2-/- V4-/q V3o/-







CHAPTER 7

176


management scenarios for olive crop in El-Fayoum. Abbreviations as in Table 7-14 (page

174).

Management

scenario

Soil profile Attainable vulnerability Field vulnerability

P N H X P N H X

Scenario #1 F-SU1 V1 V1 V1 V2 V3-/e V3-/j V3-/q V4-/t

F-SU2 V1 V1 V1 V2 V3-/e V3-/j V3-/q V4-/t


F-SU4 V2 V1 V1 V3o V4-/e V3-/j V3-/q V5o/t


F-SU6 V2 V2 V2 V3o V4-/e V4-/j V4-/q V5o/t

Scenario #2 F-SU1 V1 V1 V1 V2 V2-/- V3-/j V3-/q V4-/-

F-SU2 V1 V1 V1 V2 V2-/- V3-/j V3-/q V4-/-

F-SU3 V1 V1 V1 V1 V2-/- V3-/j V3-/q V2-/-

F-SU4 V2 V1 V1 V3o V4-/- V3-/j V3-/q V4o/-

F-SU5 V1 V1 V1 V1 V2-/- V3-/j V3-/q V2-/-

F-SU6 V2 V2 V2 V3o V4-/- V4-/j V4-/q V4o/-

Scenario #3 F-SU1 V1 V1 V1 V2 V1-/- V1-/- V1-/- V1-/-

F-SU2 V1 V1 V1 V2 V1-/- V1-/- V1-/- V1-/-

F-SU3 V1 V1 V1 V1 V1-/- V1-/- V1-/- V1-/-

F-SU4 V2 V1 V1 V3o V2-/- V1-/- V1-/- V2o/-

F-SU5 V1 V1 V1 V1 V1-/- V1-/- V1-/- V1-/-

F-SU6 V2 V2 V2 V3o V2-/- V2-/- V2-/- V2o/-







7.4 MAIZE CROPPING IN EL-FAYOUM: A SPECIAL STUDY CASE

Cultivation of maize in some parts of El-Fayoum province traditionally requires

high inputs of fertilizers and pesticides, as well irrigation with wastewater. This

section is devoted to a brief discussion about recommendations for maize

cropping, in order to reduce soil vulnerability to contamination by phosphorus,

nitrogen, heavy metals and pesticides.

In order to achieve this object, the recommended scenario includes a reduction of

the use of fertilizers, pesticides and complete elimination of additions of industrial

waste and sewage sludge (the main sources of heavy metals in El-Fayoum

depression). This recommended scenario does not assume organic agriculture:

farmers will still use fertilizers and pesticides, but under controlled conditions.


177

Results include the mean values of vulnerability for all studied soil units (F-SU1 to

F-SU6, including data from 46 soil profiles). Contamination risk class decreased for

the three outputs of Pantanal model: land, management and field vulnerabilities

for phosphorus, nitrogen, heavy metals and pesticides, as shown in Figure 7-6.

Figure 7-6. Vulnerability classes of land, management and field vulnerability under

current and recommended scenarios in El-Fayoum Province. Contaminant type: P,

phosphorus; N, nitrogen; H, heavy metals; X, pesticides. Vulnerability classes: V1, none;

V2, low; V3, moderate; V4, high; V5, extreme.

Land vulnerability Management vulnerability Field vulnerability

Vulnerabilityclasses

Contaminant types

P N H X

P N H X

SU2: Typic Haplocalcids

Current scenario

Recommended scenario

P N H X

SU3: Typic Torrifluvents

Current scenario


P N H X

SU4: Typic Haplogypsids

Current scenario

Recommended scenario P N H X

P N H X

SU5: Typic Haplosalids

Current scenario

Recommended scenario P N H X

P N H X

SU6: Typic Torripasamments

Current scenario


V1

V2

V3

V4

V5

V1

V2

V3

V4

V5

V1

V2

V3

V4

V5

V1

V2

V3

V4

V5

P N H X

V1

V2

SU1: Vertic Torrifluvents

V3

V4

V5

V1

V2

V3

V4

V5

Current scenario


Typic Torripsamments

CHAPTER 7

178

Figure 7-7. Vulnerability classes for current scenario and hypothetically recommended

scenario for all the studied soil type in El-Fayoum Province. Contaminant type: P,

phosphorus; N, nitrogen; H, heavy metals; X, pesticides.

7.4.1 VERTIC TORRIFLUVENTS

Results obtained under the actual management scenario indicate that in SU1-

Vertic Torrifluvents (506.7 km2, 66.67% of the total unit area) have a moderate

vulnerability class (V3), while the rest of the area (253.3 km2, 33.33%) falls within

the V4 class due to the risk of contamination by phosphorus. For nitrogen and

heavy metals, it was found that almost all the area is included in class V3.

Vulnerability classes of contaminants

0

5

10

15

20

25

30

P N H X

0

5

10

15

20

25

30

SU6: Typic Torripasamments

Current scenario


SU4: Typic Haplogypsids

Current scenario

P N H X

0

20

40

60

80

100Recommended scenario

0

20

40

60

80

100Current scenario

0

20

40

60

P N H X

0

20

40

60



Current scenario


P N H X

0

20

40

60

80

100

120

140

1600

20

40

60

80

100

120

140

160

SU3: Typic Torrifluvents

Current scenario


P N H X

0

100

200

300

400

0

100

200

300

400

SU2: Typic Haplocalcids


Current scenario

P N H X

0

200

400

600

8000

200

400

600

800

SU1: Vertic Torrifluvents

Current scenario


Area, km2

V1= None V2= Low V3= Moderate V4= High V5= Extreme

Typic Torripsamments


179

According to vulnerability for contamination by pesticides, it was found that V5

class includes 506.7 km2 (66.7%). The resting area falls within classes V4 (211.1

km2, 27.8%) and V3 (42.2 km

2, 5.6%).

On the other hand, data under the recommended management scenario in the

same soil units show vulnerability V2 (506.7 km2, 66.67%) and V4 (253.3 km

2,

33.3%) due to contamination risk by phosphorus. For nitrogen and heavy metals,

it was found that almost all of the area is included in V1 class. According to

vulnerability of pesticides contamination vulnerability, vulnerability classes

determined were V1 (253.3 km2, 33.3%) and V2 (506.7 km

2, 66.7%).

7.4.2 TYPIC HAPLOCALCIDS

Under current conditions, SU2-Typic Haplocalcids (382.7 km2, 90%) show high

vulnerability (V4) for phosphorus, while the rest of the area (38.3 km2, 10%) falls

into class V3. Attending to vulnerability for contamination by nitrogen and heavy

metals, 100% of the total area present moderate vulnerability class (V3). Finally,

vulnerability class for pesticides is V1 (38.3 km2, 10%) and V5 (382.7 km

2, 90%).

In contrast, under the recommended management scenario, vulnerability for

phosphorus is V2 (38.3 km2, 10%) and V4 (382.7 km

2, 90%). Vulnerability for

nitrogen and heavy metals decreased to V1 in all the area. Finally, vulnerability for

pesticides is V1 (38.3 km2, 10%) and V2 (382.7 km

2, 90%).

7.4.3 TYPIC TORRIFLUVENTS

SU3-Typic Torrifluvents spread through an area of 141 km2. Under the current

management conditions, vulnerability for phosphorus is V3 (80.6 km2, 57.1%) and

V4 (60.4 km2, 42.9%). For nitrogen and heavy metals, results showed that 100% of

the unit has a moderate vulnerability class (V3). Current vulnerability for

pesticides is V3 (40.3 km2, 28.58%), V4 (20.1 km

2, 14.22%) and V5 (80.6 km

2,

57.2%).

Under the recommended scenario, phosphorus vulnerability is V2 (80.6 km2,

57.1%) and V4 (in this case, the affected area did not vary). For nitrogen and

heavy metals, results showed that vulnerability class decreased from V3 to V1 in

all the study area. Finally, for pesticides, vulnerability also decreased to V2 in all

the study area.

CHAPTER 7

180

7.4.4 TYPIC HAPLOGYPSIDS

In SU4-Typic Haplogypsids soil unit, under current management conditions,

vulnerability for phosphorus is V3 (29 km2, 33.3%) and V4 (58 km

2, 66.6%). For

nitrogen and heavy metals, the whole unit (87 km2) was included in V3 class. For

pesticides, vulnerability was V4 (29 km2, 33.3%) and V5 (58 km

2, 66.6%).

On the other hand, under the recommended scenario, vulnerability for

phosphorus is V2 (29 km2, 33.3%) and V4 (58 km

2, 66.6%). For nitrogen and heavy

metals, vulnerability is V1 and V2 in all the unit area, respectively. Finally,

vulnerability for pesticides is V1 (29 km2, 33.3%) and V2 (58 km

2, 66.6%).

7.4.5 TYPIC HAPLOSALIDS

In SU5-Typic Haplosalids soil unit, vulnerability for phosphorus, nitrogen and

heavy metals is V3 in all the unit area. In contrast, vulnerability for pesticides is V2

(19.3 km2, 33.3%) and V3 (38.7 km

2, 66.7%).

On the other hand, the result of recommended management scenario indicates

that the whole unit has a vulnerability class V3 for phosphorus. But for nitrogen

and heavy metals, the vulnerability decreased to V2. In the case of pesticides

vulnerability was V1 (38.7 km2, 66.7%) and V2 (19.3 km

2, 33.3%).

7.4.6 TYPIC TORRIPSAMMENT

In SU6-Typic Torripsamment soil unit, vulnerability for phosphorus under the

current scenario is V4 (26 km2). Vulnerability for nitrogen and heavy metals is V3

(6.5 km2, 25%) and V4 (19.5 km

2, 75%). Finally, the whole unit area was classified

as V5 for pesticides vulnerability.

On the other hand, vulnerability for phosphorus did not vary under the

recommended scenario, while vulnerability for nitrogen decreased to V2 in all the

unit area. Finally, vulnerability the total unit area was V3 for heavy metals and V2

for pesticides under the recommended management scenario.

7.4.7 WHOLE AREA

Figure 7-8 shows the results for the whole study area. It can be summarized that

the model application results are grouped in five vulnerability classes: V1 (none)

to V5 (extreme) for each specific contaminant. Results obtained in El-Fayoum area

showed that 47.8% and 52.2% of total studied area were classified as V3 and V4

due to phosphorus contamination under the actual management scenario, but

41.9, 5.9 and 52.2% of total area were classified as V2, V3 and V4 under


181

recommended management scenario. Vulnerability for nitrogen and heavy metals

was V3 (98.7%) and V4 (1.3%) of the total area under the actual management

scenario. Finally, vulnerability for pesticides is V1 (2.6%), V3 (8.1%), V4 (17.4%)

and V5 (71.9%) under the actual management scenario,

In contrast, under the recommended scenario, vulnerability was V1 (94.4%) and

V2 (5.6% of the total area) for nitrogen, V1 (79.0%), V2 (19.1%) and V4 (1.7%) for

heavy metals and V1 (24.0%) and V2 (76.0%) for pesticides under the

recommended management scenario.

Figure 7-8. Comparison between vulnerability classes for current management scenario

and hypothetically recommended management scenario in El-Fayoum Province.

Contaminant type: P, phosphorus; N, nitrogen; H, heavy metals; X, pesticides.

V1= None V2= Low V3= Moderate V4= High V5= Extreme

Vulnerability classes of contaminantsP N H X

0

200

400

600

800

1000

1200

1400

1600

P N H X

Area, km

Current scenario Recommended scenario

Area, km2

Eutrophication and high concentration

of nutrients in the agriculture water in

El-Fayoum Province.

Burnt rice crop residues in marshlands

near Seville (Andalusia).

Olive crop in Andalusia. The farmer

used herbicide to control weeds

among the olive tree.

Pollution of irrigation water by human

waste in El-Fayoum Province.

Using animal manure as an organic

fertilizer in El-Fayoum depression.

Brick factories contribute in the

contamination of air and soil in El-

Fayoum province.

Burnt weeds in irrigation canals in El-

Fayoum.

Baher el Banat irrigation canal. This is

one of the most polluted canals in El-

Fayoum depression.

7 soil pollution risk -...

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