1. Introduction

The district of Nosy-Be is composed of five districts, this study concerns in the district CITE SEIMAD on the first district. A quarter of the population in the first district is in the CITE SEIMAD neighborhood. The number of inhabitants in this district is given by the following table

The people who live on the CITY SEIMAD use a large well for drinking water. The characteristic of this Well is given in the following table

This study is divided into three parts: the first by the bibliographic synthesis, then the results of analyzes for the physicochemical and microbiological parameters, the interpretation and the discussion of these results, we will conclude with the conclusion.

2. Bibliographic Synthesis

Well water is groundwater: the porosity and the structure of the ground determine the type of groundwater and the mode of underground circulation of the water. Generally pollution is absence in the underground water.

Classification:

Depending on the situation of the water table: free water table, captive water table and water table.

Depending on the geological nature of the terrain: alluvial aquifer, karstic nappe and basement ply. Main Features the quality of the water depends on the land because there is a balance and an exchange of materials between the ground and the water that is there. Groundwater has: Low turbidity Temperature is one of the physical parameters.

Table 1. Recommendation of the WHO

Table 2. Recommendation of the EU

Table 3. Recommendation of the EM

Low oxygen concentration

Low contamination (bacteria, viruses ...) the source of drinking water in general is surface water and groundwater

A free web is sensitive to the captive web.

The free layer is fed by the whole surface of the ground situated above it.

Metals can exist in water the presence of pollution in drinking water is very dangerous Quality standard: for drinking water is referenced by the recommendation of the World Health Organization (WHO), the European Union (U.E) and the Malagasy State (E.M).

Norm of quality

1 - Recommendation of the WHO

2 - Recommendation of EU

3 - Recommendation of the EM

3. Analysis Parameters

Temperature, turbidity to know the transparency of the water, pH to know the water is acidic, basic or neutral. Dissolved oxygen makes it possible to estimate the amount of organic matter in the water.

Salinity is the measure of the concentration of salt in water. Ammonium to know the existence of pollution in water. Calcium, magnesium, sodium and potassium are essential elements for the nutrition of human life.

4. Results of Measures

I – Physical parameters

1 – Temperature

Table 4. Represents of the temperature

Figure 1. Temperature measurement

The value of the temperature found is 16.1°C so it is acceptable for the three potability standards because the value is <25°C. [3]

2 – Turbidity

Table 5. Represents the measurement of the turbidity

Figure 2. Turbidity measurement. [1]

For turbidity, the acceptable value for drinking water is 5 NTU gold for the CITY SEIMAD Well is equal to 1.3 NTU; it perfectly meets the required condition.

3 – pH

Table 6. Represents the measurement of the pH

Figure 3. pH measurement

The pH is outside the required value because for CITY SEIMAD Well water is 6.22, while the three potability standards require this value to be 6.5 to 9, according to this results therefore the water in the vicinity of the acid. [3]

II – CHEMICAL PARAMETERS

1 – Dissolved oxygen

Table 7. Measurement results of dissolved oxygen concentration

Figure 4. Dissolved oxygen

Dissolved oxygen is 0.3 mg / L less than the value requested for WHO, EU and EM. [2]

2 – Salinity

Table 5. Measurement results of salinity concentration

Figure 5. Results salinity

Salinity is 0 so exactly meets the required condition.

3 – Ammonium

Table 6. Measurement results of ammonium concentration

Figure 6. Results ammonium

The concentration of ammonium found is 0.05 mg / L, are lower than the three concentration values for international standards. [5]

4 – Sodium

Table 7. Measurement results of sodium concentration

Figure 8. Results sodium concentration

The sodium concentration found is very low compared to the required values is for the Well is 3.38 mg / L, and the standard is 200mg / L.

5 – Potassium

Table 8. Measurement results of potassium concentration

Figure 9. Results potassium concentration

The potassium concentration of CITY SEIMAD wells is in excess of the values required for drinking water standards

6 – Calcium

Table 9. Measurement results of calcium concentration

Figure 10

The concentration of calcium found is very small compared to the standards required for drinking water. So the well of City SEIMAD is not good. [6, 10]

7 – Magnesium

Table 11. Measurement results of magnesium concentration

Figure 11. Results of magnesium concentration

The magnesium concentration is very low at the values required for international standards. [10]

8 – Iron dosage

Table 12. Measurement results of iron concentration

Figure 12. Results of iron concentration

Iron is only available for CITY SEIMAD well water. [9]

9 – Aluminum

Table 13. Measurement results of Aluminum concentration

Figure 14. Results of Aluminum concentration

Aluminum is only available for CITY SEIMAD well water. [4]

10 – Copper

Table 14. Measurement results of copper concentration

Figure 15. Results of copper concentration

Copper exists but in the form of a trace, so no problem for drinking water [8].

11 – Lead

Table 15. Measurement results of lead concentration

Figure 16. Results of lead concentration

Lead also does not exist for this water [11].

12 – Chlorides

Table 16. Measurement results of chlorides concentration

Figure 17. Results of chlorides concentration

The concentration of chloride found is very low by international standards for drinking water, so the water is not good. [7]

III- MICROBIOLOGICAL ANALYSIS

Figure 18. Results of the microbiological

Table 18. Measurement results of the microbiological

The water CITY SEIMAD Well is not microbial.

5. Interpretation of results

- Physical parameters

The temperature is 16.1°C, below 25°C for international standards, the turbidity 1.3 NTU less than 5 NTU for the condition of drinking water and the pH is 6.22 excluded for the standard of potability. The turbidity is 100%, the pH is 88% and the temperature is 100% for the standards required for drinking water, so from these values it can be written that the physical parameter corresponds perfectly to 96% of the values required for international standards.

- Chemical parameters

The dissolved oxygen is 0.3 mg / L, the required concentration is <2mg / L so it is acceptable.

Salinity does not exist for the water of CITY SEIMAD.

Ammonium is 0.05 mg / L, the required value is <0.5 mg / L, so the water is less polluting.

The potassium concentration is higher than the values requested for WHO, EU and ME.

The concentration of sodium found is 3.38 mg / L, but the required values are 200 mg / L; the calcium concentration found is 4.8mg / L, their required values are 100mg / L and the magnesium is 0.97mg / L, the required value is 50mg / L.

In conclusion, according to this comparison the water is low in sodium, calcium and magnesium.

Metals like copper, aluminum, iron and lead do not exist for the water of CITY SEIMAD.

- Microbiological analysis

from the values found have can write: Revive microorganism at 36°C, Intestinal Enterococci and Spores of microorganisms meet 100% for the standards required for drinking water, while Coliform bacteria and Eschercia coli respond to 95%, In conclusion at the bacteriological level, according to this value, it is possible to write the result that it meets 98% of the norm required for drinking water.

6. Conclusions

Physical parameters are eligible for the three international standards required for drinking water.

Chemical parameters: the concentrations found are almost insufficient to drinking water standards, for which I propose the demineralization before being used. No trace of metals for this water well CITY SEIMAD.

No danger also at the level of the bacteria for the well water of CITY SEMAD.