Groundwater contamination study of the upper part of the dibdibba aquifer in Safwan Area (Southern Iraq)‎

Dissertant

Manhi, Hazim Karim

Thesis advisor

al-Kubaysi, Qusayy Yasin

Comitee Members

al-Shamma, Aysar Muhammad
al-Jabbari, Miqdad Husayn Ali
al-Dahhan, Sadi Abd al-Jabbar Musa

University

University of Baghdad

Faculty

College of Science

Department

Geology Department

University Country

Iraq

Degree

Master

Degree Date

2012

English Abstract

The study area is located in the extreme southern part of Iraq in Basra governorate, between latitudes (30º 05′ 00″- 30º10′ 00″) and longitudes (47º40 ′ 00″- 47º 47′ 00″) expanded over about 60500 m2 including the residential area of Safwan district and vicinity.

Safwan area is considered as an important agricultural area in Iraq that supplies other areas of country by main vegetable crops, where the agriculture is the predominant profession there.

Recently, and in addition to some other activities, groundwater in Safwan has been exploited to produce drinking water by more than eight desalination plants.

The groundwater of the Dibdibba aquifer represents the main and lone natural water source in the study area.

The Dibdibba aquifer consists of two parts, upper, unconfined, that having brackish water, and lower, semi-confined, with saline water.

The two parts separated from each other by a hard clay bed called locally (Jojeb).

The two parts are connected hydraulically, naturally due to the vanishing or local thickness decrease of the separator bed and artificially by penetrating the Jojab by water wells drilling operations.

The static water level ranges from 7.24 - 14.

m a.s.l.

Based on the climatic data of Al-Basra meteorological station for the period 1980-2010, the climate is classified as sub-arid to arid climate due to the decrease in the annual averages of rainfall and the decrease in the temperature averages which causes the drought conditions domination especially after 1997.

Twenty-three well are chosen to be sites for hydrochemical sampling.

The samples were collected in two seasons, dry and wet, and analyzed to determine the physical and chemical properties and compared with the national, international standards, and different water classifications, to estimate the groundwater suitability for different purposes.

In general, groundwater in the study area is of Na2SO4 type in the dry period and NaCl type in the wet period with the continental origin of groundwater.

Concerning the groundwater uses, it is unsuitable to direct use as a human drinking, industrial, and building purposes, but it varies from good to unacceptable for livestock drinking and unfitting for poultry.

In spite of unsuitability of Safwan groundwater for irrigation, it has been used successfully in irrigation due to high infiltration soil conditions and continuous irrigation.

The comparison testified the occurrence of a saline contamination in groundwater in addition to the high concentrations of Ca, Mg, Na, Cl, SO4, and B that reached contamination levels.

Three trace elements are also considered as contaminants, which are Pb, Ni, and Cd.

The human activities especially agriculture are the main source of the groundwater contamination together with the different waste sources such as sewage, garbage, desalination plants, and polluted air, in addition to the natural sources representing in the III Dibdibba sediments and the effect of Jabal Sanam rocks that appeared clearly in the west and northwestern parts of the study area.

In order to estimate The GWQI for irrigation purposes, two methods are used which are, the standard method for examination of water and wastewater recommended by American Public Health Association, which named APHA and Analytic Hierarchy Process, which named AHP method.

In APHA method, thirteen parameters have been chosen which are (electrical conductivity (EC), total dissolved solids (TDS), Ca++, Mg++, Na+, K+, Cl-, SO4=, HCO3-, NO3, sodium adsorption ratio (SAR), pH, and B), while in AHP method, Expert Choice software was used to creating the hierarchy and giving weighting for each one of the six chosen parameters that are (EC, SAR, B, Cl, HCO3, and NO3).

The mentioned parameters in the two methods were chosen according to Ayers and Westcot (1989) classification for irrigation water that recommended by Food and Agriculture Organization FAO.

The results are represented in spatial distribution maps using ARC GIS.

In both two-method, the resulted WQI values are classified into three classes (good, moderate, and poor water).

The two-method results show a considerable congruence, where the poor water appeared in the west and northwestern parts in both maps showing the effects of the high concentrations and the influence of Jabal Sanam., while the good and moderate water cover about 80-90% of the study area.

There are some differences between the two results that ascribed to the parameters number used in each method.

To assessing aquifer vulnerability to pollution, GOD technique has been used, which depends on three factors, G groundwater occurrence, O overlaying lithology and D depth to groundwater.

The resulting map clarifies that the upper part of the aquifer has a moderate class of aquifer pollution vulnerability and this sensitivity is higher in the places where the groundwater is closer to the surface.

Main Subjects

Earth Sciences, Water and Environment

Topics

• Pollution
• Groundwater
• Iraq
• Safwan(City)

No. of Pages

135

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-608845