Study of Distribution of Trace Elements in Tigris River in Baghdad City

 

Zainab Jawad Kadhim, Mohammed F. Hamaza, Mohammed T. Khethi

College of Science, Thi-Qar University, Al-Nasiriya, Iraq

*Corresponding Author E-mail: mohammed.f@sci.thiqaruni.org

A Base line studies of the distribution of trace elements in Tigris River in Baghdad City have been determined .The present work entitled sampling water from Tigris River between Al-Kademei City and Al-Jadera at five stations. Total concentrations of five heavy metals, cadmium (Cd), copper (Cu), iron (Fe), lead(pb) and zinc (Zn) were determined using atomic absorption spectrometry in order to assess their contamination levels of the river. Their concentrations were found to vary between (0.08-1.26 µg/l) (0.02-1.43 µg/l)(0.84-66 µg/l)(0.54-2.78 µg /l)(0.43-1.9 µg/l) respectively  .The results suggest that the trace elements present in this originated from low diverse sources and the study showed that pollution with some of this metals  are high  compared with global standard that’s request accurate watching period and continue  test  in regular periods .

 

 

1. INTRODUCTION:

Water pollution is considered as the most complex problem because of its wide defects and its close relationship to human and its diffusion⁽¹⁾.

 

Metals that are naturally introduced into the Rivers come primarily from such sources as rock weathering, soil erosion, or the dissolution of water-soluble salts ⁽²⁾. Naturally occurring metals move through aquatic environments independently of human activities, usually without any detrimental effects. The metals added by human activities have affected the water quality. Some of these metals are essential for proper metabolism in all living organisms yet toxic at high concentrations; other metals currently thought of as non-essential are toxic even at relatively low concentrations. ⁽³⁾

 

Major sources of toxic metals arising from human activities are domestic and industrial wastewaters and their associated solid wastes.

 

In the most cases trace element concentrations in bottom sediments indications of water pollution. Soluble fractions of trace elements are, in most aquatic environments, rapidly absorbed either by clay or organic compounds and deposited in sediments or they are caught by plankton and root tissues of aquatic plants. Thus, concentrations of trace elements in selected samples of aquatic compartment reflect either chemical composition of bedrocks or anthropogenic influence^(4).

 

Trace elements that occur and/or may occur in human body are as follows: Essential: Cu ,Fe and Zn Non-essential: Cd, Pb. (In bold are elements of high toxicity to humans).⁽⁵⁾

 

Tigris is the most important river and sources of fresh water in the areas surrounding of Baghdad City.

 

The objective of the present study are to determine the original distribution of trace elements in Tigris River in Baghdad City and to evaluate the role civil and factories jetsam as a source of river pollution.

 

In order to accomplish these aims, five sampling sites were selected to represent different region of Tigris River. A reference stations was chosen at the Tigris River north Baghdad City included in the present survey and their positions are show (Figure 1). The sampling program carried out over a period of 7 months. (July2011 to January 2012).

 

2. GENERAL DESCRIPTION OF THE SAMPLING STATIONS:

The positions of stations were determined by the Global Positioning System (GPS).

1      The first station: In the beginning of the river in the north latitude (33 23, 2.75 N º) and east longitude (45 º 45), the river here has no cities or large pollution sources for a long the distance.

2      The second station: It's about 1km south of Al-Nasiriya city before electrical power plant in the north latitude  (32 Â º 06) and east longitude ( 46 Â º 01). This station characterizes by many agricultural fields and plants on its banks.

3      The third station: It is about 3 km south of  Al-Nasiriya city at electrical power plant, which discharge hot water to the river in the north latitude (31 Â º  29) and east longitude (46 Â º 2).There are salt areas on the left side and agricultural fields on the right .

4      The forth station: It lies about 1 km after electrical power plant, in the north latitude (31 Â º 21) and east longitude (46 Â º 14). This station characterizes with low water level and narrow width.

5      The fifth station: It lies where the river enter Al-Nasiriya city, in the north latitude (31 Â º 33) and east longitude (46 Â º 15). It is affected by domestic wastewater and workshops from near cities which populated with about (75000) people.

                       

3. MATERIALS AND METHODS:

Subsurface (1m) water samples have been collected from all stations utilizing the sampling devise Recommended by EPA 2004 (5).The samples analysis by using Atomic Absorption PG 990 with suitable hollow cathode lamps .

 

4. RESULTES AND DISCUSSION:

Heavy metals released into the Tigris River by both natural processes and human activities, can be distributed among several different stations within the water environment and the level of metals in Tigris River is listed in table 1.

 

Our data indicate that the level of Zn observed in Tigris River water lie above  the range of values reported by EPA standard . The highest conc. of Zn were recorded sta.5(2.78 µg/l) and lowest was (0.54 µg/l)at sta. 1.This indicate that Tigris River pollution has possibly discharge and Urban runoff and electricity generation station in Dora(at St. 5) may be consider as the most significant sources of metals entering Tigris River .

 

Cu revealed the highest conc. 1.43 µg/l at sta.3. The lowest (0.02µg/g) was recorded in sta.1. Copper dissolved in the Tigris River comes mostly from industrial and municipal wastewaters. Concentrations of dissolved copper generally increase in the downriver direction, especially near urban centers.

 

The highest concentration of Cd was (1.26µg/l) and the lowest was (0.08µg/l) were recorded in sta.1.During weathering processes, Cd forms simple compounds, such as CdO, Cd(OH)₂, CdCl₂ and CdF₂ that are easily mobile and follow Zn, The median Cd concentration in world ocean waters has been estimated to range from 0.07 to 0.11 μg/l^{. (7)}

 

 

 

Fig (1) Map of Tigris river showing the position of stations

 

 

Fig.2: Concentration µg\l of heavy metals observed in the Tigris River water

 

 

Table1: Concentration µg\l of heavy metals observed in the Tigris River water 

 

Iron plays an important role in marine environments as a micronutrient for organisms and its low bioavailability may limit growth of phytoplankton that are critical for the oceans primary production ⁽⁸⁾. Iron concentrations in landfill leachate and ground water can create various technologic and environmental problems. Redox conditions of in landfill leachates are very complex, but reducing conditions may predominate. Therefore concentrations of Fe in groundwater around waste disposal sites may vary in the broad range from 3 to 5 500 mg/ l ⁽⁹⁾, whereas Fe contents of groundwater in unpolluted zones of temperate humid climate average 0.75 mg /l ⁽⁵⁾.

 

The highest conc. of Fe was encountered in sta.5 (66µg/l), while lowest values were recorded from sta.1 was (0.8 µg/l).

 

Pb showed increments in sta.5 (0.2µg/l) and the lowest values were recorded in stas.1 was (0.03µg/l). Range concentration of heavy metal can be cleared by the series 

 

Fe > Cd > Cu >Zn > Pb

 

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6-      U.S. EPA (2003) Ambient water quality criteria. EPA-440/5-80-071. Office of water regulations and standards. Criteria and Standard Division. Washington, DC.

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Received on 13.07.2013       Modified on 28.07.2013

Accepted on 06.08.2013      © AJRC All right reserved