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Water Quality and Contamination

SCI 207: Dependence of Man on the Environment

ABSTRACT

Ground water is the biggest source of drinking water available to human population around the world and is rapidly being polluted because of industrialization and increasing demands of agriculture around the world. A set of simple experiments were done to find out what kind of changes do some of these contaminants cause in ground water. Samples of tap water and bottled water were also analyzed for safety. Chemicals like oil, vinegar and soap cause turbidity, odor and color change in water samples. Tap water is much safer to drink than bottled water because it contains less contamination than bottles water.

INTRODUCTION

Ground water is present below the surface in porous rocks and is susceptible to contamination by natural and especially human related activities. Large amounts of chemicals like soap and detergents, fertilizers and pesticides, pharmaceutical by-products are discharged in to fresh water aquifers every day. These contaminants leach in to the soil and dissolve in ground water. Different contaminants have different rates of solubility and degradation once they reach the underground water table either by simple flow or by the downward movement of rain water. The ground water may become contaminated with both organic and inorganic substances especially heavy metals like Cadmium, Chromium and Nickel, etc. (Christensen et al, 2001). Pharmaceutical wastes can cause cancer in human cells. (Krifa et al. 2013). Many pharmaceutically active chemicals reach groundwater sources almost untreated and cause contamination. (Herber, 2002). Increase in the emissions of carbon dioxide by burning fossil fuels is the single largest cause of environmental degradation resulting not only in global warming but also causing acid rain which alters the pH of ground water. Water is a universal solvent; however, its dissolving properties are very sensitive to changes in temperature and pH. Global economic growth has, unfortunately, resulted in high levels of carbon dioxide emissions worldwide with the current annual rate at 3.3% from 1.3% in the last decade. (Canadell et al, 2007). The demands of agricultural output have put a lot pressure on fresh water sources. Rapid industrialization has led to huge increase in the usage of ground water. The untreated industrial wastes are released back in to rivers and streams causing further pollution. Industrial units are the biggest users of ground water today with a share of almost 22% of the total water supply available in the aquifers. (Brown and Brian, 1998).

MATERIALS AND METHODS

Dry clean beakers of 50 cm3 capacity were filled with samples of ground water. Each beaker contained 25 cm3 of water sample. Nothing was added to the water sample in the first beaker. 15 cm3 of oil cooking oil was added to the second water sample. Same volume of commonly available vinegar was added to the third sample and a pinch of commonly available laundry detergent powder was added to the fourth water sample. Potting soil was added to all other samples. The sixth sample contained a mixture of soil and oil whereas the seventh water sample contained. The last sample contained soil with detergent in water. The experiment was carried out at room temperature and pressure. Experiments were also carried out to measure the difference in concentrations of ammonia, phosphates, chloride etc. in bottled and tap water samples.

RESULTS

SAMPLE	CHANGES OBSERVED
	COLOR	TRUBIDITY	ODOR
1	None	None	None
2	None	None, however, a layer of oil formed at the top	May have been blocked by the layer of oil
3	None	Slight, cloudy appearance	Typical vinegar smell
4	None	Slight, cloudy appearance with a thin layer of bubbles	None
5	Light brown color	Medium, suspended soil particles mostly at the top layers of water	Typical potting soil smell detected
6	Light brown color	A shiny layer of oil at the top	Potting soil smell detected
7	Brownish grey	Slight	Typical vinegar smell detected
8	Brown	Dark fog like appearance	None

Ammonia Test Results

Water Sample	Test Results
Tap Water	0
Dasani® Bottled Water	0

Chloride Test Results

Water Sample	Test Results
Tap Water	0
Dasani® Bottled Water	500
Fiji® Bottled Water	500

Table 4: 4 in 1 Test Results
Water Sample	pH	Total Alkalinity	Total Chlorine	Total Hardness
Tap Water	7	40	1.0	0 - Soft
Dasani® Bottled Water	3	80	0	120
Fiji® Bottled Water	8	0	1.0	50

Phosphate Test Results

Water Sample	Test Results
Tap Water	10
Dasani® Bottled Water	0

Absence of any color or smell gave the water in sample 1 a pleasing appearance. Although, it might not be absolutely pure, this water sample might be safe enough to drink as it did not show any unpleasant physical effects of contamination. Oil is less dense than water so it formed a thick layer at the top in the second water sample. This layer prevented any contact of air with the surface of the water. No particular smell was noted. It might be possible that the odor was blocked by the layer of oil at the top. Vinegar is a colorless liquid and weakly acidic. When vinegar was added to the third water sample it did not cause any specific change in color, however, it did cause typical vinegar smell making it a bit unpleasant. When vinegar was added with potting soil in sample 7, however, the color of the water changed to brownish grey. The color change may have been due to the change in pH of the soil. Addition of detergent in sample 4 resulted in the formation of bubbles because of lowered surface tension of water. The dark fog like texture observed in sample 8 might be due to dispersion of soil particles within the water because of low surface tension. Analysis of the tap water samples and bottled water samples clearly showed that tap water is the cleanest source of drinking water since it contains the least amount of contamination.

DISCUSSION

The addition of various chemicals affects the quality of drinking water and alters its chemical composition. It is vital to regularly check the level of different contaminants in ground water. Series of experiments were carried out to check the type of changes which occur in ground water when different contaminants like oil and soap are added. As opposed to popular belief, bottled water came up with more contamination than tap water which proves that drinking tap water is much safer than drinking bottled water. However, there are some aspects that need detailed study like the effect of temperature on the solubility of contaminants in water. A systematic study is also needed to review the levels of contaminants in ground water at different times of the day because humans are mostly active during day time so the concentrations of contaminants must be high during the day. However, this idea needs to be verified through proper research. Study can also be carried out to review the status of contaminants at different times of the year to reveal any possible relation between the rate of leaching and degradation and seasonal variation.

CONCLUSION

Series of experiments were carried out to check if how the quality of drinking water changes when different contaminants are added. Noticeable changes were observed in turbidity, color and odor when oil, detergent and vinegar were added. Experiments were also carried out to ascertain if bottled water is safe for consumption as against tap water. The results were totally unexpected because tap water turned out is far less contaminated than bottled water. However, more systematic research is needed to study the parameters of ground water contamination.

REFERENCES

Canadel, J.G., Que’re’, C.L., […..] and Marland, G. 2007. Contributions to accelerating atmospheric carbon dioxide growth from economic activity, carbon intensity and effeiciency if natural sinks. Proct Natl Acad Sci USA. 104(47): 18866-18870.

Christensen TH, Kjeldsen P, Bjerg PL, Jensen DL, Christensen JB, Baun A (2001). Biogeochemistry of landfill leachate plumes. Appl. Geochem., 16: 659–718.

Esceincelabs.com (2012). Introduction to Science. Retrieved from: http://managedcourse.next.ecollege.com/pub/content/49a6ebcb-6f67-4a76-a20a- 7c1f374dd49c/SCI207.W2.Laboratory.pdf

Herberer, T. (2002). Tracking persistent pharmaceutical residues from municipal sewage to drinking water. J. Hydrol….

Industry to agriculture ratio from Lester R. Brown and Brian Halweil, “China’s Water Shortage Could Shake World Food Security,” World Watch, July/August 1998, 13; industrial share of consumption from Sandra Postel, Dividing the Waters: Food Security, Ecosystem Health, and the New Politics of Scarcity, Worldwatch Paper 132 (Washington, DC: Worldwatch Institute, September 1996), 14.

Krifa, M., Cherif, A., Barillier, D., Mosrati, R., Ghedira, L. & Mansour, H. (2013). Human cell death in relation to DNA damage after exposure to the untreated and biologically treated pharmaceutical wastewater. Environmental Science and Pollution Research.20(6),3836-3842.