Ewemen Journal of Analytical & Environmental Chemistry

© 2017 Ewemen Resources Limited / EJAEC. All rights reserved.

2017 | Vol. 3 | Issue 2 | Pg. 157 - 160

Ewemen Journal of Analytical & Environmental Chemistry ISSN 2488-913X

Available online at http://ewemen.com/category/ejaec/

Full Length Research

ASSESSMENT OF TOTAL HARDNESS IN GROUND AND SURFACE WATERS IN ANKPA LOCAL GOVERNMENT AREA OF KOGI STATE, NIGERIA

1Obaje G.M., 1Ejeh J.B. and 2Abiaziem C.V.

1Department of Chemistry, Kogi State College of Education Ankpa, Kogi State.

2Department of Science Laboratory Technology, Federal Polytechnic Ilaro, Ogun State.

ABSTRACT

Received 24 August, 2017 Revised 2 September, 2017 Accepted 6 September, 2017 *Corresponding Author’s Email: [email protected]

One of the factors that establishes the quality of a water supply is its degree of hardness. Hard water contains high mineral content. Water hardness is usually noticed because of difficult in lathering soap and the formation of a scum in the bathtub. This study is aimed at determining hardness of selected water bodies from Ankpa Local Government Area (LGA) of kogi State. A total number of 21 water samples were collected from Maboro river and six boreholes over a period of three months in the area. EDTA titrimetric method and Eriochrome black T as indicator, were used for the analysis. Statistical mean and range were used to analyze the data obtained. Results revealed the average total hardness for all samples to be within the range of 12 mg/L to 55 mg/L. The boreholes total hardness varied from soft to moderately soft. Maboro river water value 12±2.5 mg/L is soft. The hardness values of 12±2.5 to 55±43 mg/L from the different water samples were within World Health Organization regulatory limit of 100-200 mg/L for drinking water. This suggests that the water hardness quality of River and boreholes in Ankpa LGA of Kogi State are safe for both domestic and industrial purposes. Keywords: Water hardness; Surface water; Ground water; EDTA; Titrimetric method; Erichrome Black T; Ankpa; Kogi, Nigeria

INTRODUCTION

One of the most common chemicals known to both the educated and the illiterate is water. This is probably due to its abundance and usefulness both to human, animals and plants. It is not out of place to say that water is involved in almost all activities; water is not only used all over the world in large quantities for drinking purposes, but it is used in even greater quantities for washing, bleaching, dyeing, cooking, raising steam to drive engine or turbines to generate electricity and as a solvent in industrial processes.

Odesina (2003) said that, water which does not latter readily with soap is described as hard water and this property is called hardness of water. Thompson (2000) said that hard water causes excessive consumption of soap used for cleaning purpose. Sodium soaps react with multivalent metallic cations to form a precipitate, thereby lose their surfactant properties, the lathering does not take place until all hardness ions precipitate out. This precipitate adheres to surfaces of tubes, sinks, dish washer and may stain clothing.

Ewemen Journal of Analytical & Environmental Chemistry 2017, 3(2): 157 - 160 Obaje et al.

www.ewemen.com page 158

Hard water is water that has high mineral content (in contrast with a soft water). Hard water is formed when water percolates through deposits of calcium and magnesium containing minerals such as limestone, chalk and dolomite. Hard drinking water is generally not harmful to one’s health (WHO, 2003) but can pose serious problem in industrial settings, where water hardness is monitored to avoid costly breakdown in boilers, cooling towers and other equipment that handles water. In domestic settings hard water is often indicated by a lack of suds formations when soap is agitated in water, and by the formation of limestone in kettles and water heaters, wherever water hardness is concern, water softening is commonly used to reduce hard water adverse effects. Stocchi (1990) states that hardness of water is a measure of the total concentration of the calcium and magnesium ions express as calcium carbonate. Water becomes hard by being in contact with soluble divalent, metallic cations. The two main cations that cause water hardness are: Calcium ion (Ca2+) and Magnesium (Mg2+). Calcium is dissolved in water as it passes over and through limestone deposit. Magnesium is dissolved as water passes over through dolomite and other magnesium bearing formations. Due to the fact that ground water is in contact with these geologic formations for a longer period of time than surface water, ground water is usually harder than surface water (Jumoke, 2005). The mineral ions that cause the hardness of water include Ca2+, Mg2+, Fe3+, SO2-4 and HCO-3. The concentration of Ca2+ ions is greater than the concentration of any other metal ion in water and so, water hardness is measured in terms of CaCO3. The degree of hardness of the water is classified in terms of its calcium carbonate concentration as follows (Miroslay and Vladimir, 1999). Table1: The degree of hardness of water

Degree of hardness Hardness (mg equivalent CaCO3L-1 ) Soft <50 Moderately soft 50 – 100 Slightly hard 100 – 150 Moderately 150 – 200 Hard 200 – 250 Very hard >300 Source: Miroslay and Vladimir (1999)

There are two types of hard water; temporary hard water and permanent hard water.

Temporary hard water is caused by the presence of dissolves calcium hydrogen trioxocarbonate (iv), Ca(HCO3)2, which decomposes on heating. Temporary hardness of water can be easily removed by boiling. On boiling, the calcium hydrogen trioxocarcabonate (iv) decomposes to calcium trioxocarbonate (iv) CaCO3, which is insoluble and this brings the calcium ions out of the solution as a precipitate (equation 1). Once the calcium ions are out of the solution, the soap that is added to the water will be available for the formation of lather (Ababio, 2013). Ca(HCO3)2(aq) CaCO3 (s) + H2O (l) + CO2(g)……..(1) Insoluble

Temporary hardness can also be removed by using slaked lime Ca(OH)2 (equation 2). Ca(HCO3)2(aq) + Ca(OH)2(s) 2CaCO3(s) +2H2O(l) ……….(2) Soluble slightly soluble Insoluble

Permanent hardness of water is caused by the presence of calcium and magnesium ions in the forms of soluble tetraoxosulphate (vi) and chlorides. Permanent hardness of water can only be removed by using chemicals. It can be removed by precipitating the calcium and magnesium ions from solution. The chemicals employed are all soluble sodium compounds which will form insoluble precipitates with the calcium and magnesium ions. Washing soda, caustic soda and permutit or zeolite are some of the common chemical used in the removal of permanent hardness (Ababio, 2013). Permutit or zeolite is an ion exchange resin used industrially and in the home for softening water. Zeolite is a naturally accruing sodium aluminiumtrioxosilicate (iv) and commonly known as sodium zeolite. The resin can also be prepared artificially. As the hard water is passed through the resin, the sodium ions will go into solution while the unwanted calcium and magnesium ions take their place in the complex salt (Ababio, 2013). Hard water tastes better than soft water because of the dissolved minerals in it. The calcium salts present in hard water, when taken in the animals, help to build strong teeth and bones. Hard water helps animals such as snails and crabs to make their shells. These shells are making mainly of calcium trioxocarbonate (iv).



Hard water can be supplied in pipes made of lead as this type of water does not dissolved lead. Soft water dissolves lead. If supplied in lead pipes, it will cause lead poisoning. The most suitable reagent that is used for the determination of hardness of water is ethylenediaminetetraacetic acid (EDTA). In analytical chemistry, EDTA is used in complexometric titration and analysis of water hardness or as a masking agent to sequester metal ions that would interfere with the analysis (Domiguez and Ward, 2009). This study is aimed at determining hardness of selected water bodies from Ankpa Local Government Area of Kogi State. Ankpa community is overdependence on underground water through indiscriminate sinking of boreholes because the only surface water (Maboro river) has been under severe environmental stress and are being threatened as a result of human developmental activities. There is also paucity of data on the total hardness of surface and ground waters in Anpka LGA. The data obtain in this study will serve as a baseline data of the area for future use. MATERIALS AND METHODS

Materials

All reagents used were of analytical grades, BDH England. Sample Collection

The samples were collected with the aid of clean polythene bottles from respective sampling points and analyzed immediately after each collection. The samples were collected consecutively within three months on 27th May, 28th June and 30th July 2014, in triplicates. Maboro River and six boreholes were sampled. Determination of water hardness

100mL of water sample was measured into a conical flask, 4mL of ammonia ammonium chloride buffer (pH=10) was added, followed by 2 drops of eriochrome black T indicator. This was titrated against 0.01M EDTA solution until the wine red (Pink) colour of water solution changed to blue. And this was repeated twice for each sample (Standard Methods, 1998). Total hardness is given as:

mg/L (CaCO3) = 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 0.01𝑀 𝐸𝐷𝑇𝐴 𝑢𝑠𝑒𝑑 (𝑚𝑙 ) ×1000

𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒 (𝑚𝑙 )

The arithmetic mean and the range were the statistical methods used for the analysis of the results. RESULTS AND DISCUSSION

The results of analysis of the water samples from the different sources over the three month period is as presented in Table 2.

Table 2: The total hardness of water samples calculated in mg/L CaCO3

Sampling location Hardness (mg/L) Range 1 Maboro River 12±2.5 9.5-14.5 2 Munaja borehole 13±2.3 10.5-15 3 Okenyi borehole 29±6.3 23-35.5 4 Sebima borehole 19±5.6 13.5-24.5 5 Oriko borehole 12±0.5 11-12 6 Ogodo borehole 55±43 28.5-104 7 K.S.C.O.E Ankpa borehole 14±8.3 5.5-22

The results showed that total hardness for all the samples to be within the range of 12±2.5 to 55±43 mg/L. The highest value, 55±43 mg/L, was from Ogodo borehole, followed by 29±6.3 mg/L which was from Okenyi borehole and the least was Oriko borehole which is 12±0.5 mg/L. Maboro river water hardness value 12±2.5 mg/L is softer than all the boreholes considered except Oriko borehole. Based on the classification of the degree of hardness of water as reported by Miroslay and Vladimir, (1999), all the water samples fall within the range of softness (<50) except Ogodo borehole water that is moderately soft (50–100). According to Jumoke (2005) ground water is usually harder than surface water because ground water is in contact with geologic formation for a longer period of time than surface water. The result of 12±2.5 to 55±43 mg/L obtained from the analysis of Maboro River and six different boreholes water samples as mentioned above complied with the similar study carried out on streams and boreholes water in Anambra State by Mmuo et al (2013). The hardness values of 12±2.5 to 55±43 mg/L from the different water samples were within WHO regulatory limit of 100-200mg/L for drinking water (WHO, 1993). This suggests that the water hardness quality of River and boreholes in Ankpa LGA of Kogi State are safe for both domestic and industrial purposes. Hard drinking water is generally not harmful to one’s health except very hard (WHO, 2013) but can pose serious problem in industrial settings, where water hardness is



monitored to avoid costly breakdown in boilers, cooling towers and other equipment that handles water. CONCLUSION

The result obtained from this study revealed all the water samples investigated to be within the range of softness (<50) except Ogodo borehole water that is moderately soft (50–100). Hard water is not harmful to health, except when it is very hard (>300). Based on the World Health Organization Standard, the water quality of River and boreholes in Ankpa Local Government Area of Kogi State are safe for both domestic and industrial purposes. ACKNOWLEDGEMENT

The authors acknowledge Mrs. Obaje Goodness for her support. CONFLICT OF INTEREST

None declared. REFERENCES

1. Ababio OY (2013). New school chemistry for senior secondary school (6rded.). Onitsha: Africana First Publisher PLC, pp.297-299.

2. Jumoke E (2005). Comprehensive chemistry for senior secondary schools Lagos: Johnson Publisher, pp.163-166

3. Odesina IA (2003). Essential chemistry for senior secondary school. Ikeja:Tonad publisher. PP:249-251

4. Standard Methods for the Examination of Water and Wastewater (1998). – #2340 Hardness. (20th eds), American Public Health Association / American Water Works Association / Water Environment Federation, Washington, DC. Available from: <https://beta-static.fishersci.com/content/dam/fishersci/en_US/documents/programs/scientific/technical-documents/white-papers/apha-hardness-standard-methods-white-paper.pdf > [Accessed 1 Sept. 2017].

5. Stocchi M (1990). Ecological Association of water hardness with prevalence of childhood. Dermatitis Res 94 (1): 33-71.

6. Thompson, J.J. (2000). Photochemical transformation in aqueous solution and possible environmental fate of Ethylenediaminetetraacetic acid (EDTA). Ecotoxicol Environ Safety 19: 55-63.

7. Miroslay R and Vladimir NB (1999). Practical environmental analysis. Royal Society of Chemistry, Cambrige, UK, pp: 175-179

8. Mmuo UE, Omaka NO, Ibe GU, Okoye OG and Ezenwamadu CF (2013). Estimation of total hardness in stream and borehole water in Abatete Town in Anambra State Nigeria. In: U. Augustina (eds.), Proceedings of 8th Annual

International Conference ANACHEM Chemical Society of Nigeria [CSN] Anambra State Chapter, pp. 6-10

9. Domiguez K and Ward WS (2009). A novel nuclease activity that is activated by Ca2+ chelated to EGTA”. Syst Biol Reprod Med 55(5): 193-199.

10. WHO (1993). Guidelines for drinking water quality. Health criteria and other supporting information.

11. WHO (2003). Hardness in drinking water, world report on reducing risk and promoting healthy life. Geneva, World Health Organization.

Article’s citation

Obaje GM, Ejeh JB and Abiaziem CV (2017). Assessment of total hardness in ground and surface waters in Ankpa Local Government Area of Kogi State, Nigeria. Ew J Anal & Environ Chem 3(2): 157 – 160. Authors’ contributions

Author OGM designed the study, wrote the procedure and interpreted the data. Author EJB and ACV anchored the experiments. Authors OGM and ACV managed the literature searches and produced the initial draft. All authors read and approved the final manuscript.

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Ewemen Journal of Analytical & Environmental Chemistry