IMPACT STUDY OF AGRICULTURAL PRODUCTS ON THE …€¦ · Impact Study of Agricultural Products on the Groundwater Supplying the Ramsar 'Merja Zerga' Ecological Site 85 [email protected]

http://www.iaeme.com/IJCIET/index.asp 84 [email protected]

International Journal of Civil Engineering and Technology (IJCIET)

Volume 10, Issue 10, October 2019, pp. 84-99, Article ID: IJCIET_10_10_009

Available online at http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=10&IType=10

ISSN Print: 0976-6308 and ISSN Online: 0976-6316

© IAEME Publication

IMPACT STUDY OF AGRICULTURAL

PRODUCTS ON THE GROUNDWATER

SUPPLYING THE RAMSAR 'MERJA ZERGA'

ECOLOGICAL SITE

Kaoutar LAGLITI*, Akram FARHAT, Mohammed FEKHAOUI, Latifa TAHRI

Laboratory of Geo-biodiversity and Natural Patrimony, GEOPAC research center, Scientific

Institute, Mohammed V University, Rabat, Morocco.

*([email protected])

ABSTRACT

In order to provide a clear answer on the origin of the different pollutants found in

the Merja Zerga, this work has been divided into two parts:

The identification of pesticides in the region by the inventory of agricultural pesticides used,

their toxicological classification according to the WHO classification

The monitoring of groundwater quality in the region around the Merja Zerga, and the

analysis of some trace elements (heavy metals and pesticides).

This study allowed us to outline the interaction between agricultural practices and

groundwater quality in the region where the ecotoxicological risks represented by the

various uses are present.

Indeed, the inventory allowed us to identify 45 substances used in the region with

a dominance of insecticides.

On the other hand, the evaluation of the quality of these waters by the monitoring

of some physical and chemical tracers shows a good quality at the level of the study

area around the Merja Zerga (Kenitra province) according to Moroccan standards.

With regard to the analysis of trace elements (heavy metals and pesticides) in

these groundwater shows a lack of contamination of these waters by these elements

with the exception of lead but with negligible values and below the Moroccan

standards and denotes the absence of a possible impact of agriculture on the quality of

these waters. Which is related to road traffic and the intensive use of fuels in

agricultural actions.

Keywords: Merja Zerga, groundwater, agriculture, heavy metals, pesticides

Cite this Article: Kaoutar LAGLITI, Akram FARHAT, Mohammed FEKHAOUI,

Latifa TAHRI, Impact Study of Agricultural Products on the Groundwater Supplying

the Ramsar 'Merja Zerga' Ecological Site. International Journal of Civil Engineering

and Technology 10(10), 2019, pp. 84-99.

http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=10&IType=10

Impact Study of Agricultural Products on the Groundwater Supplying the Ramsar 'Merja Zerga'

Ecological Site


1. INTRODUCTION

Morocco and particularly the Gharb plain are experiencing a great increase in agricultural

development. Due to the flexibility of the climate in the region which allows a diversification

of the types of cultures and plantation. This development has resulted in a growing demand

for seedlings and a growing diversification of crops.

The Merja Zerga constitutes the most important Moroccan wetland [4], which is known

by a well-developed industrial and commercial agriculture, notably in the north and north-east

part of the lagoon implying a massive use of inputs (fertilizers, pesticides) that affect the

ecological integrity of the site [8], which affects the water resources required to maintain a

well-balanced ecosystem [5].

The present work consists first and foremost in carrying out an inventory of the various

pesticides through a field survey, also their classification according to their use, and their

danger according to the WHO, and the evaluation of the degree of contamination of the

waters. groundwater in the study area, which is the main source of drinking water for douar

people, trace metals and pesticides. In order to deduce the hydrological functioning of the

Merja Zerga, in order to design a management and backup program.

The presence or absence of these residues is therefore of great health interest to predict

any water intoxication. It is also necessary to know the concentrations allowing to present a

risk for the consumer.

2. MATERIALS AND METHODS 2.1. Study Area

The Merja Zerga is a lagoon located on the Moroccan Atlantic coast, at the seaside village of

Moulay Bousselham about 120 km north of Rabat and 40 km south of Larache (Figure 1). Its

geographical coordinates are :

34˚ 47 '- 34˚ 52' north latitude,

06˚ 13 '- 06˚ 14' west longitude.

Figure 1. Location of study Area [7]

Kaoutar LAGLITI, Akram FARHAT, Mohammed FEKHAOUI, Latifa TAHRI


The hydrological regime of the Merja Zerga lagoon is influenced by (Figure 2):

The freshwater inflow of the Nador Canal and Oued Drader,

The groundwater recharge (groundwater) of Dhar El Hadchi and El Fahis.

Marine waters conditioned by the tide gauge,

The waters of the lagoon system of Merja Zerga have different origins. The inflow of

marine waters is the most important, with an average volume of about 12 000.106 m3 / year

or more than 98% of the waters of this paralic system [1].

A mapping of Merja Zerga habitats (Figure 2) has been established [2] using the MedWet

methodology, based on a hierarchical model combining criteria related to hydrology,

vegetation and sedimentology [3]. Of all the habitats identified in the site, the intertidal

mudflats constitute the main component, with approximately 1,300 ha or more than 44% of

the wetland. The halophilic grasslands totaling 910 ha are in second position, while the

peripheral grasslands extend over 380 ha.

Figure 2. Habitat mapping of the Merja Zerga [7].

2.2. Land cover

Dewatering and hydrological modifications for agricultural purposes affected the habitats of

Merja Zerga. In addition, the intake of fresh water from the drainage of the agricultural area

of Gharb in Merja Zerga via the Nador Canal has softened the waters of the southern part of

the lagoon, causing the plant facies to change by reconquest of macrophytes such as Juncus

acutus, Phragmites sp and Typha sp.


Ecological Site


The analysis of the ancient maps (1950, 1960) of the region shows that the supply of fresh

water to the lagoon was initially provided by local rainfall and the Drader River. In addition,

the analysis of old aerial photographs (1950 and 1960) shows a large extension of reed beds,

which were in turn severely reduced later due to overgrazing and cutting.

Figure 3 Map of land occupation of Merja Zerga. Map made by Landsat-7, TM image analysis taken

in 2007, plus field survey. [5]

The land used for agriculture in Moulay Bousselham totals 1881.04 ha (25.21% of the

total area, ORMVAL Dlalha). It is divided into irrigated land (1626.73 ha) and bour land

(254.31 ha).

The crops are very diversified with the dominance of cereals (29.33%) and agro-industrial

crops "strawberry" (27.43%). Then follow, oilseed crops (18.11%), mainly sunflower and

groundnuts, fruit growing (9.95%), agricultural fallow (7.96%), and vegetables, legumes and

vegetables. only 3.85%, 2.32% and 1.05% respectively.

Our surveys and field surveys have shown an extension of crops at the expense of this

wetland. Indeed, to the west of the wetland the strawberry growing areas have taken some of

the areas that normally were habitat to Juncus maritimus and other persistent to persistent

emerging maize-type habitats are currently restricted to an area of 3 ha dominated by Typha.

To get an idea of the state of land occupations, we compared the data provided by the

municipal monograph (2007) of Moulay Bousselham and Bahhara Ouled Ayad (Table 1). It

appears that agriculture occupies a key place in the land occupation. In fact, the total area of

useful agricultural area in the two communes is 18915 ha, or 74.9% of the total area. In

second place, come the forests with a rate of 13.8% of the total area. The pastures and

uncultivated lands arrive last with a recovery of 11.3%.



Table 1. Land cover in the communes of Moulay Bousselham and Bahhara Oulad Ayad

municipalities Land use Area

(in ha)

Occupancy rate

per

municipality

(in%)

Moulay Bousselham Agricultural

area

irrigated 3206 28

Bour 3564 31

Forest 2535 22

Path and uncultivated land 2115 19

Bahhara Oulad Ayad Agricultural area irrigated 2748 20

Bour 9397 68

Forest 950 7

Path and uncultivated land 755 5

Total 25270 100

2.3. Justification of the choice of sampling

The sampling points were chosen at Kenitra province and especially at the Dhar El Hadechi

water table and El Fahis water table at the douars surrounding the Merja Zerga (Figure 4).

Sampling in these areas was chosen because of the vulnerability of the aquifers at this

level. It should be noted that the various douars visited use well water as the sole source of

drinking water, which may explain the importance of these analyzes from a hygienic point of

view.

Figure 4: selected sampling points around the Merja Zerga


Ecological Site


3. RESULTS AND DISCUSSION

3.1. Inventory of pesticides for agricultural use in the study area

The inventory of the different pesticides was carried out thanks to a survey carried out in the

field. The census was conducted through direct contact with traders, identifying the types of

pesticides sold in the region as well as the specific uses for the crops characterizing the study

area.

The main marketing channels for pesticides

In sum, there were 25 traders (Table 2) in the coastal zone. The intensive agricultural

intensification that this area is experiencing thanks to the availability of groundwater close to

the surface and of good quality for irrigation. However, the other side of the coin, is that this

development remains compromised in view of the strong pressure on the water table and the

misuse of agricultural inputs (fertilizers and pesticides) making the threats of overexploitation

and degradation of the quality of agricultural products. water a visible reality in the region.

The public authorities (in particular the Sebou Basin Hydraulic Agency) have also started a

participatory approach for the sustainable management of the coastal water table for more

than 3 years, but it seems that the efforts made so far have not not a palpable impact on the

ground.

The traders in the coastal zone are concentrated in the centers of Souk El Had (9 traders)

and Dlalha (9 traders).

Table 2: Number of merchants by city center, type of merchant and education level of the seller or

farmers in our study area can go to buy their products for agricultural use.

Cities

Number of traders

per city center

merchant nature

level of instruction of the seller

Dlalha 9 6 retail sale and 3 retail sale /

semi-wholesaler

1 agronomist, 3 technicians, 1

level Bac + 2, 2 level Bac and 2

secondary level

Kenitra 5 3 retail sale and 2 retail sale /

semi-wholesaler

4 technicians and 1 level Bac

Souk El Had 9 7 retail sale and 2 retail sale /

semi-wholesaler

All technicians

Souk Larbaa 2 1 retail sale and 1 retail sale /

semi-wholesaler

All technicians

The analysis of the tables of pesticides that we identified from our inventory carried out in

the region allowed us to find 45 active ingrédients :

19 insecticides mainly organochlorines, synthetic pyretrinoids and carbamates;

13 fungicides represented mainly by dithiocarbamates;

7 nematicides consisting of fumigants;

And 2 herbicides mainly phenoxy acids.

In the study area, insecticides and fungicides are most commonly used in agriculture as

nematicides and herbicides. In fact, the different crops grown in the region are mostly

irrigated crops and favor the development of fungi, hence the excessive use of fungicides.



Table 3. The number of commercial products identified at the study area level for fungicides,

insecticides, nematicides, herbicides

Pesticides Number of products approved

according to the Phytosanitary

Index

Number of commercial

products identified

Insecticides 208 19

Fongicides 264 13

Nématicides 120 7

Herbicides 121 2

Total 713 41

Figure 5 Relative percentage of pesticides used in the stady area

Main pesticides used for the main and intensive crops in the study area

Cereals

The total area occupied by common and durum wheat is about 1560 ha. But in the future

cereals will decrease but phytosanitary treatments will increase. The most used pesticides are :

Table 4 The most used fungicides in the study area

Commercial specialty Active ingredient Rate/ha Number of

application

Soft wheat,

hard wheat,

and corn

IMPACT

Flutriafol + Carbendazime

propinazole

1l/ha

1

Table 5. The most used herbicides in the study area


application

Soft

wheat,

hard

wheat,

and corn

AFRIT480

PRINTAZOL 75

2,4-D

2,4D + 2,4MCPA

0,8l/ha

12,5 g/ha

2 à 3

2 à 3


Ecological Site


Vegetables

Vegetables occupy an area of about 940 ha.

Table 6. The most used fungicides in the study area

Commercial

specialty Active ingredient Rate/ha

Number of

application

vegetables

MANEB 80

DITHANE

ANTRACOL 70 WP

Manèbe

Mancozèbe

Propinèbe

200 g/hl

200 g/hl

250 g/hl

1

1

1

Sunflower

Sunflower, although it is not a main crop in the Gharb cropping system and is rather a

substitute crop for farmers, still occupies an area of about 35 to 40 ha.

Table 7. The most used insecticides in the study area

Commercial

specialty Active ingredient Rate/ha

Number of

application

sunflower

FURADAN 5G

DURSBAN

ARRIVO 25 EC

KARATE 5 EC

LANNATE 25 WP

Carbofuran

Chlorpyriphos-éthyl

Cypermethrine

Lamba-cyhalothrine Méthomyl

Methomyl

20 kg/ha

150 cc/ha

300 cc/ha

250 cc/ha

200 g/hl

1

1

1

1

1

PEANUTS

The groundnut occupies an area of about 700ha. The pesticides used are :



application

Peanuts

PELT 44

NESPOR 80 PM

Thiophanate-métyl

Manèbe

100 g/hl

200 g/hl

1

1



application

Peanuts

TALSTAR 10 EC

LANNATE 25 WP

Bifenthrine

Méthomyl

30 à 40 cc/hl

150 à 250 cc/hl

2

2

Strawberries

As is the case for other crops in Gharb and throughout Morocco, a number of unapproved

pesticides are used on the strawberry plant but the foreign client authorizes them on this crop,

knowing that it is mainly used for export. On the other hand, there is a list of products that can

be used on the strawberry plant in compliance with the standards of the two standards:



GlobalGap and Tesco Nature's Choice. This list is developed based on the list of products

supplied by the client and list of approved products provided by the DPVCTRF (currently

ONSSA management). This list is updated and revised to track changes in national legislation

and phytosanitary legislation at destination country level as well as customer requirements.

The strawberry in the Gharb occupies an area of about 50 ha. This crop is also among the

most pesticide-consuming crops.



application

strawberries

DITHANE M45

Mancozèbe

200 g/hl

3 à 4



application

sttrawberries

PRIMOR 50 DG

DECIS EXPERT

Pyrimicarbe

Deltaméthrine

75 g/hl

100 cc/hl

2

2

Table 12. The most used nematicides in the study area


application

strawberries

MOCAP 20 EC

NEMACUR 10 GR

VIDATE

Ethoprophos

Phenamiphos

Oxamyl

40 l/ha

50 kg/ha

6 à 8 l/ha

1

1

2

Avocado

Avocado in the study area currently occupies an area of about 22ha. The pesticides used are :



application

Avocado

ANTRACOL 70 WP

Propinèbe

250 g/hl

1 à 2

Table 14. The most used nematicides in the study area


application

Avocado

MOCAP 20 EC

NEMACUR 10 GR

VIDATE L

Ethoprophos

Phenamiphos

Oxamyl

40 l/ha

50 kg/ha

6 à 8 l/ha

1

1

2


Ecological Site


Classification of the main pesticides identified according to the ecotoxicological and

toxicological risk

For the ecotoxicological and toxicological classification, the classification of the World

Health Organization has been adopted which is based on the danger that a pesticide may pose

to human and animal health. As reported in the second chapter of this report, the hazard

according to the WHO [9] means the degree of health risk (risk of a single or multiple

exposure over a relatively short time) that may accidentally occur for a manipulator. a

pesticide in accordance with the manufacturer's guidelines and standards for storage and

transport of pesticides.

Table 15. Classification of pesticides used in the region, according to WHO [9]:

Pesticides Classe Ib Classe II Classe III

Insecticides 5 6 3

Fongicides 0 0 12

herbicides 0 1 1

According to this table the insecticides used in the study area contain the most dangerous

active substance (class Ib), 6 moderately hazardous substances (class II) and 3 slightly

dangerous substances. For fungicides despite their high numbers, they contain only class III

products that are slightly dangerous. In addition, herbicides are poorly used in the region,

shows a class II and a class III.

Figure 6 WHO classification of pesticides [9]

Thus, the use of pesticides in the region and the comparison of their toxicity makes it

possible to highlight the risks associated with these substances. Indeed, only two methomyl

elements and the class Ib Methamidophos insecticides appear to represent a potential risk and

require future monitoring in the different components of this ecosystem.

0

2

4

6

8

10

12

14

insecticides fongicides herbicides

Classification of pesticides according to WHO:

Classe Ib Classe II Classe III



The physicochemical characteristics of groundwater in the study area

All the results of the physicochemical analyzes are represented in Table 16. The whole will be

discussed according to the MOROCCAN STANDARDS (2002) (Official Bulletin N ° 5062

of 30 Ramadan 1423 fixing the standards of potability for human consumption) [6].

Table 16. Results of physico-chemical analyzes of groundwater

stations depth(m) pH T°C Conductivity

(µs/cm)

S1 7 7,67 20,4 432

S2 9 7,28 17,2 1380

S3 12 7,49 20,3 396

S4 12 7,70 20,3 372

S5 3 7,35 20,1 449

S6 7 7,47 20,2 440

S7 15 7,60 21,2 672

S8 12 7,53 20,1 548

S9 7 7,46 20,1 644

S10 6 7,12 19,3 651

S11 25 6,61 20,3 421

Temperature

Figure 7: Evolution of temperatures in the different stations (S)

The values obtained are between 17.2 ° C as a minimum value and 21.2 ° C as the

maximum value recorded at the wells around the Merja Zerga in the depth of the wells does

not exceed 25m depth and therefore reflects the effect of the climate temperature. However,

this variation does not seem to be related to the depth of the wells.

0

5

10

15

20

25

S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11

Temperature T°C

Stations


Ecological Site


pH

Figure 8 The spatial evolution of the pH of the samples

Generally measured pH values are of mild alkalinity. They range between 6.61 as a

minimum value and 7.70 as the maximum value recorded from the wells around the Merja

Zerga. These waters are well buffered.

Conductivity

Figure 9: Spatial variation of groundwater conductivity

The analysis of the evolution of the conductivity makes it possible to distinguish two

classes:

Excellent class with a value less than 750 μs / cm. These are wells 1, 3, 4, 5, 6, 7, 8, 9, 10, 11.

Middle class 2 with a conductivity of 1380 μs / cm good. One point represents this class

station 2.

Moreover, the evolution of this parameter highlights the role of the effect of the geological

nature on the quality of the water. This influence is very visible at the level of the wells where

6

6.2

6.4

6.6

6.8

7

7.2

7.4

7.6

7.8

S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11

pH

0

200

400

600

800

1000

1200

1400

1600

S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11

Conductivity (µs/cm)



the mineralization is the highest in relation with the leaching of neighboring lands (clayey and

sandy ground) and the thrusting of waters heavily laden with dissolved salts.

The metallic trace elements

Iron, zinc, mercury, copper, chromium

The analysis of the other metallic elements (Fe, Zn, Hg, Cu, Cr) in the groundwater shows a

total absence of contamination of these waters by these elements, the values obtained are

negative therefore lower than the Moroccan norm (2 mg / l) and denotes the absence of a

possible impact of agriculture on the quality of these waters. According to the Moroccan

norm, these waters are of a good category.

Copper

Figure 10: The spatial evolution of Lead in the studied area

Despite the presence of some peaks (S3, S4, S6, and S10) the values obtained are lower

than the Moroccan standard of 10 μg / l and classify these waters in the category of good

quality. But this presence, which is linked to road traffic and the intensive use of fuels in

agricultural actions, suggests a potential for local contamination of groundwater in the region.

Pesticides

Douars in the study area rely primarily on groundwater for water supplies, but there is a

dearth of information on the volume and quality of these groundwaters. Given the threat of

contaminated groundwater to human health, it is important to gather more information on the

quality of groundwater in the area.

Indeed, the level of contamination of groundwater in our study area by the desired

pesticides (Figure 11) shows a total absence of all types of pesticides, these waters seem less

subject to pollutants.

This absence could be related to the decrease in precipitation and water inflow during the

last 2 years, and that the contamination of these waters is mainly related to the leaching of the

soil after the treatment periods and probably to the geological nature of the region. may not

favor the infiltration of these elements.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11

lead µg/l


Ecological Site


Added to this is soil drainage, the depth of the water table, the type of storage, the

mobility and the degradation of the pesticide considered. S1 :

S2 :

S3 :

S4 :

S5 :

S6 :

S7 :

S8 :

S9 :

S10 :



S11 :

Figure 11: Chromatographs of the analyzed pesticides

4. CONCLUSION

The study of the inventory of pesticides and their various qualitative and quantitative uses

based on the inventory of pesticides and the spatial monitoring of the groundwater quality of

the study area by the analysis of TMEs and pesticides, we has made it possible to outline the

interaction between agriculture and water quality in the region and the ecotoxicological risks

represented by the various uses.

In fact, the use of pesticides in the region and the comparison of their toxicity makes it

possible to highlight the risks associated with these substances. Only the methomyl and

methamidophos elements which are active substances characterizing these class Ib

insecticides appear to represent a potential risk and require future monitoring in the different

components of this ecosystem.

In addition, the analysis of the ETMs of these groundwaters shows a lack of

contamination of these waters by these elements and denotes the absence of a possible impact

of agriculture on the quality of these waters.

Despite the presence of some peaks in Lead, particularly at wells (S3, S4, S6, and S10),

the values obtained are lower than the Moroccan standard of 10 μg / l and classify these

waters in the category: good quality.

However, these values for Lead in the area suggest a possibility of local contamination of

the deep layers of the area and open the way for future investigation to better understand this

presence.

The same findings were noted for pesticides that show no contamination in the region.

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[1] BENHOUSSA, A. 2000- Caractérisation des habitats et micro distribution de l’avifaune

de la zone humide de Merja Zerga (Maroc). Doctorat d’Etat. Dac. Sci., Rabat.

[2] DAKKI, M., HAMMAN F., HAMMADA S. 1998- Cartographie des habitats naturels

d'une zone humide côtière méditerranéenne : les marais de Smir (région de Tétouan,

Maroc).

[3] FEKHAOUI, M. ; SERGHINI, A. ; ELBLIDI, S. ; EL ABIDI, A. 2009- la réserve

biologique de Merja Zerga et son environnement immédiat : hydrologie et évaluation des

impacts de la l’utilisation des intrants (engrais et pesticides).

[4] RGUIBI IDRISSI, H. 2008- Greening strawberry cultivation in Merja Zerga : impact

essessment study. WWF Internationa – Living Water Programm.


Ecological Site


[5] NORMES MAROCAINES 2002- bulletin officiel N°5062 du 30 ramadan 1423 fixant les

normes de potabilité à la consommation humaine.

[6] GNINBA A., BENHOUSSA A., EL AGBANI M.A., DAKKI M., THEVENOT M. 2006-

Etude phénologique et variabilité interannuelle d’abondance des charadriidés das un site

Ramsar du Maroc : la Merja Zerga

[7] TOUZANI, S. 2000- Contribution a l’aménagement intégré de la lagune de Merja Zerga.

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[8] FARINHA J.C., COSTA L.T., ZALIDIS G.C., Mantzavelas A.L., Fitoka E.N., Hecker N.

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[9] WHO, 1998- « Directives de qualité pour l'eau de boisson. », Deuxième édition, Additif

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Documents

IMPACT STUDY OF AGRICULTURAL PRODUCTS ON THE …€¦ · Impact Study of Agricultural Products on the Groundwater Supplying the Ramsar 'Merja Zerga' Ecological Site 85 [email protected]