Abstract

A village was chosen as the project site. 12 samples were collected, 9 from the hand pumps, 1 from the village tap, 1 from the city tap, and 1 from bottles as reference. 4 experiments have been conducted and confirmed by being conducted by an independent firm. The results were consistent and showed that the Total Dissolved Solids rise in some samples to dangerous levels. Microbiological testing, and analysis for Nitrates are strongly suggested as a continuation of this project.

Introduction

In the village, there is a 100 m³ capacity water tank fed from an 80 m deep well. Its water is distributed by gravity to all houses that require domestic drinking water and pay the fixed fees.

Hand Pump

Hand pumps are most popular outside residential areas, namely in the fields. They are used for drinking purposes for both people, and cattle. They are usually dug not far away from the irrigation streams. Hand pumps are usually dug to a depth of 16 - 24 m and sometimes to a depth of 32 m.

Water streams are used in villages for the disposal of domestic used water. At the same time, fertilizers and pesticides are extensively used cultivated land. These are potential sources of contamination for water wells that are the source of hand pump water.

There is not a known system for taking water samples for inspection from any responsible authority. The only evaluation is done by the users on basis of taste, smell, and rate of flow. Recently the rate of occurrence of kidney disease has increased significantly and people started to need hemodialysis peritoneal dialysis which is an expensive action and not available all the time.

The purpose of this investigation is to test the hand pump water in the village and evaluate its suitability for drinking.

Village Choice and the Collection of Samples

The village chosen was Zawyet El Bakly - Monofeyya Governorate. The choice of the village was mainly based on the existence of many contacts at that village who are expected to facilitate the work there.

A village map was made and the locations of the pumps were marked and labeled in a manner that will make it easy to recognize the source of every sample. You can notice in the following map that pump locations are marked with red crosses and labeled A, B, …, I. You can also notice that most pumps are named after the people who dug them as donations for general use.

The village was visited on Thursday March 23^rd, 2000 and three samples were taken from each pump and numbered 1, 2, and 3. Samples were taken in 150 cc glass bottles and hermetically closed.

Samples were taken from 9 hand pumps, 1 sample was taken from a house tap in the village and was labeled T, 1 sample was taken from a city tap and was labeled CT, and one last sample was taken from bottled water (Baraka) of known characteristics and was labeled BW.

Testing

The analysis were done using the Micro Scale Technique developed by Dr. Mahmoud El Marsafy. In this technique, small containers, and small and simple apparatus are used instead of standard ones. This made it quite easy to perform the tests and obtain adequate results. Although one of the sources suggested 192 tests necessary for water quality, 4 tests were carried out here. In addition to the tests that we carried out, an independent company was asked to conduct the same tests. As will be shown, the results were consistent.

We conducted the following four tests:

1. pH measurement: This is done by transferring 1 ml of a water sample into a small vial and adding 2 drops of Universal Indicator. The resulting color indicates the pH. Yellow/Green [g.y] indicates a pH of 7, it is only obtained from distilled water. Green [G] indicates pH of 7.3 and Green/Blue [G.B] indicates pH of 7.5

   International limits for drinking water : pH 6.5 - 8.5

2. Alkalinity expressed as mg bicarbonate/L: All water samples will contain dissolved salts of calcium bicarbonate [Ca (H CO₃ )₂] and magnesium bicarbonate [Mg (H CO₃ )₂]. The total bicarbonate will be determined by titration with a very dilute solution of Hydrochloric acid (HCl) using the universal indicator. Titration will be carried out on 1 ml of the water sample to which two drops of universal indicator is added. The acid will be added by a fine tipped dropper, and the number of drops required to obtain a red color noted. A reference "Baraka" sample must be similarly assayed. This sample contains 325 mg/l bicarbonate. Thus, the alkalinity value of the water sample can be determined in mg [H CO₃]^-/L.

   Calculations:
   Baraka sample had 10 drops of H Cl/ml sample. 1 drop of H CL is equivalent to 32.5 mg [H CO₃]^-/L
   Alkalinity of water sample = no. of drops x 32.5 mg [H CO₃]^-/L

   	Measurement of conductivity

   This value is also an indication of temporary hardness of the sample.

3. Total Dissolved Solids (T.D.S.) expressed as mg/L: Conductivity is measured in mA as the intensity of the current passing between two electrodes submerged in 2 mL of the sample and connected to a 9 V DC source. The millimeter range is kept as 20 ma Two paper clip steel wires are used as electrodes.

   Calculations:
   Conductivity of Baraka (reference sample containing 440 mg T.D.S./L) sample = 2.7 ma
   mg T.D.S / L / ma = 440/2.7 = 163
   T.D.S. of any sample in mg/L = Conductivity in ma x 163

   International limit for drinking water = 500 mg/L (not to exceed 1000 mg/L)

4. Total Residue after complete evaporation: A rapid comparative estimate of the total dissolved solid content of the water can be obtained on a Microscale by complete evaporation of 5 drops of sample (delivered from a very fine plastic tipped dropper) on an aluminum sheet placed on a hot plate (120 watts). The residue of water samples can be compared with standard reference water samples.

Results

a) Results of our experiments:

b) Results obtained from the independent firm Pfizer Egypt:

The results show that:

1. The pH is within limits.
2. The T.D.S. are above the allowable value (500 mg/L) in most cases but that they are below the max. allowed (1000 mg/L).

The Manganese content depended greatly on depth. It was well below the allowable (0.1) for the village tap water (0.034) while it was above the allowable for all pump water, it even exceeded the max. (0.5) in two cases.

Recommendations

We strongly recommend that this investigation be pursued concerning: microbiological analysis, and analysis for nitrates. The deadline that we had did not allow us to perform these tests that we believe of vital importance for the case on our hands.

Acknowledgment

We wish to express our thanks and gratitude to Dr. Ahmed El Sawi Shoukry for suggesting the project, and to him and Dr. Mahmoud El Marsafy for their teaching, guidance, and help, and for donating a lot of their valuable time for our project.

The Project Reviewers

Bernd Eggen, Amelia Irion, John Lovell, Brad Roscoe , Hossam El Badawy