INTRODUCTION:

Microorganisms can be found in raw water from rivers, lakes and groundwater. While not all microorganisms are harmful to human health, there are some that may cause diseases in humans. These are called pathogens. Pathogens present in water can be transmitted through a drinking water distribution system, causing waterborne disease in those who consume it [1].

In order to combat waterborne diseases, different disinfection methods are used to inactivate pathogens. Along with other water treatment processes such as coagulation, sedimentation, and filtration, chlorination creates water that is safe for public consumption [2,3].

For more than 100 years many public water systems add chlorine (a process known as “chlorination”) to their water supply for the purpose of disinfection. Disinfection kills or inactivates harmful microorganisms which can cause illnesses such as typhoid, cholera, hepatitis and giardiasis [4].

Chlorine is added to drinking water as elemental chlorine (chlorine gas), sodium hypochlorite solution or dry calcium hypochlorite. When applied to water, each of these forms “free chlorine,” which destroys pathogenic (disease-causing) organisms [5,6].

Chlorination also offers a number of benefits including:

• Reduces many disagreeable tastes and odors.

• Eliminates slime bacteria, molds and algae that commonly grow in water supply reservoirs, on the walls of water mains and in storage tanks.

• Removes chemical compounds that have unpleasant tastes and hinder disinfection.

• Helps remove iron and manganese from raw water.

Chloride ion concentration above 250 mg/L can produce a distinct taste in drinking water as shown in table1 [7].

Table1. Chloride ion levels in drinking water and its acceptability.

Chloride levels expressed in mg/L	Acceptability
0 - 250	Acceptable
250 - 500	Less than desirable
500 - 1000	Undesirable
Over 1000	Unsatisfactory

The Canadian drinking water quality guideline for chloride is an Aesthetic Objective (AO) of less than or equal to 250 milligrams per litre (mg/L). At concentrations higher than 250 mg/L, the sodium associated with chloride may be a concern to people on sodium-restricted diets [8,9].

While protecting against microbial contamination is the top priority, water systems must also control disinfection byproducts (DBPs), chemical compounds formed unintentionally when chlorine and other disinfectants react with natural organic matter in water. Drinking water chlorination could form a group of byproducts known as trihalomethanes (THMs), including chloroform. Trihalomethanes are associated with several types of cancer and are considered carcinogenic [10-14].

The aim of this research is the determination of chloride ion concentration in drinking water of Al Hawash area.

MATERIALS AND METHODS:

Samples collection:

A total of 30 samples of Al Hawash area drinking water were randomly taken. Analysis was conducted during the same day of bringing the samples. The analyzing procedure was done during November 2015. The work is done in laboratory of toxicology at Al Hawash Private University (HPU).

Method of analysis:

Mohr’s method (precipitation titration) is used for the determination of chloride ions in water sample. This method determines the chloride ion concentration of a solution by titration with 0.02N silver nitrate and the indicator used is 5% potassium chromate solution [15,16].

RESULTS AND DISCUSSION:

In this study, chloride ion concentration was determined in all of 30 samples of drinking water of Al Hawash area. Chloride ion concentration was found to be between 17.5 mg/L and 56.8 mg/L with 33.638 mg/L as an average and 9.219 as a standard deviation. Results are presented in table 2 and table 3. It is found that chloride ion concentration in all of drinking water sample was within internationally accepted limit which is less than 250 mg/L.

Table 2. Concentration of chloride ion in drinking water samples expressed in mg/L

Concentration expressed in mg/L	Number of sample	Concentration expressed in mg/L	Number of sample
56.8	16	17.75	1
17.75	17	28.4	2
30.53	18	28	3
35.5	19	39	4
35.5	20	34.79	5
21.3	21	31.95	6
21.3	22	35.5	7
22.72	23	35.5	8
23.43	24	42.6	9
35.5	25	35.5	10
35.5	26	49.7	11
24.85	27	42.6	12
31.95	28	44	13
35.5	29	35.5	14
34.08	30	46.15	15

Table 3. Minimum, maximum, average and standard deviation values for chloride ion concentration in drinking water samples.

Standard deviation	ِِAverage	Maximum	Minimum
9.219592	33.63833 mg/L	56.8 mg/L	17.75 mg/L

CONCLUSION:

Chlorination is a very popular method of water disinfection that has been used for many years. It has shown to be effective for killing bacteria and viruses.

Although chlorination does have some drawbacks, it continues to be the most popular, dependable, and cost-effective method of water disinfection. This study showed that the concentration of chloride ion in drinking water was within internationally accepted limit. This requires strict and continuous control for the levels of these anionic ion in drinking water.

REFERENCES:

1. White G. The Handbook of Chlorination. 2nd Edition. Van Nostrand Reinhold Company, New York. 1986; 2^nd ed.

2. American Water Works Association. Manual of Water Supply Practices: Waterborne Pathogens. Denver: American Water Works Association. 1999; 1^st ed.

3. American Water Works Association. Water Quality Division Disinfection Systems Survey Committee Report. Journal of the American Water Works Association. 9; 2000: 24-43.

4. White GC. Current chlorination and dechlorination practices in the treatment of potable water, wastewater and cooling water. In: Jolley RL, ed. Water chlorination: environmental

5. impact and health effect. Ann Arbor, MI, Ann Arbor Science.1; 1978:1-18.

6. Dychdala GR. Chlorine and chlorine compounds. In: Black SS, ed. Disinfection, sterilization and preservation. Philadelphia, PA, Lea and Febiger. 1977;2^nd ed:167-195.

7. Chlorine and hydrogen chloride. Geneva, World Health Organization. (Environmental Health Criteria, No 21).1982:1-95.

8. Illinois department of public health, division of environmental health. Commonly found substances in drinking water and available treatment. 1-8.

9. Department of National Health and Welfare (Canada). Guidelines for Canadian drinking water quality. Supporting documentation. Ottawa. 1978.

10. Copenhagen, WHO Regional Office for Europe. Sodium, chlorides, and conductivity in drinking water: a report on a WHO working group. 1978 (EURO Reports and Studies 2).

11. Backer LC, Ashley DL, Bonin MA, Cardinali FL, Kieszak SM and Wooten JV. Household exposures to drinking water disinfection by-products: whole blood trihalomethanes levels. J Expo Anal Environ Epidemiology. 10(4);2000:321-6.

12. Richardson SD. The role of GC-MS and LC-MS in the discovery of drinking water disinfection by-products. Journal of Environmental Monitoring. 4(1); 2002:1-9.

13. Rook J.J. Formation of haloforms during chlorination of natural waters. Water Treatment Examination.23; 1074: 234-243.

14. (WHO) World Health Organization. Guidelines for drinking-water quality, 2nd edition: Health Criteria and other supporting information. World Health Organization, Geneva.2; 1996, 2^nd ed.

15. (WHO) World Health Organization (1993). Guidelines for drinking-water quality: Recommendations. World Health Organization, Geneva.2; 1993; 2^nd ed.

16. Sheen R T and Kahler H L. Effects of Ions on Mohr Method for Chloride Determination, Ind. Eng. Chem. Anal. Ed. 10(11); 1938: 628-629.

17. Kraemer E O and Stamm A J. Mohr’s Method for the Determination of Silver and Halogens in other than Neutral Solutions. J. Am. Chem. Soc. 46(12); 1924:2707- 2709.

Received on 17.01.2016 Modified on 15.03.2016

Research J. Pharm. and Tech. 2016; 9(6):709-710

DOI: 10.5958/0974-360X.2016.00133.5