Special Prob

Comparative Analysis of Drinking Water From Brgy. Calajunan, Mandurriao and Brgy. Pakiad, Oton and Associated Health Risk

A Special Problem presented toHilario Taberna Jr.

In partial fulfillment of the requirementsIn PH 175 (Environmental Health)

Proponents

Andradra, Thresdale De Pedro, Jobel

Estrada, Leo John NathanielFortuna, Edward Paul

Garzon, Dana MaeInosanto, HiroyukiOliva, Mel VincentPaler, Josan Moira

Sanchez, Xyra Angelie Tan, Leonard

May 2012

INTRODUCTION

Wastes are materials that are not products produced for the market for which the generator has no further use in terms of his/her own purposes of production, transformation or consumption, and of which he/she wants to dispose. It may be generated during the extraction of raw materials, the processing of raw materials into intermediate and final products, the consumption of final products, and other human activities. Residuals recycled or reused at the place of generation are excluded. (OECD 2003) Waste is directly linked to human development, both technological and social. The compositions of different wastes have varied over time and location, with industrial development and innovation being directly linked to waste materials. Examples of this include plastics and nuclear technology. It poses environmental costs and therefore environmental health hazards as it attracts rodents and insects which harbour gastrointestinal parasites, yellow fever, worms, the plague and other conditions for humans (Ray 2008). Exposure to hazardous wastes, particularly when they are burned, can cause various other diseases including cancers. Waste can contaminate surface water, groundwater, soil, and air which cause more problems for humans, other species, and ecosystems.

A sanitary landfill is a site where waste is isolated from the environment until it is safe. These industries generate large quantities of municipal solid wastes per day but unfortunately, there is no treatment and disposal facility for the management of the wastes from these areas (PIA 2011). It also provides a livelihood for families dependent on the dumpsite. This practice poses a major concern, specifically pertaining to the health consequences that dumpsites have on the environment, particularly on the contamination of adjacent surface and ground waters used as drinking water sources for many communities. Studies (Sia Su 2004; Torres et al.1991) confirmed that harmful chemical and bacterial contaminants are introduced into drinking water sources, particularly in communities that are in close proximity to dumpsites.

It has been established that the continuous consumption of unsafe drinking water directly threatens the health and life of individuals (Sia Su 2005; Lee et al. 2002; Semenzaet al. 1998). Consumption of drinking water from unsafe and uncertain sources has indicated various health risks that may include cancer, nephrotoxicity, central nervous system effects, and even cardiovascular diseases (Fauciet al.1998). Drinking water sources contaminated with harmful chemical contaminants particularly cadmium, nitrate-nitrogen, sulfate, and bacterial contaminants may bring about diarrheal illnesses (Fauci et al. 1998; Gupta et al. 2001).Epidemiological studies are conducted to estimate ,measure, and establish the links between the environmental impacts on health. Studies by Ostro et al. (1998); Tiwari(1997), and De Motta and Mendes (1993) showed that the level of exposure of individuals to the pollutants might be measured in damage to health associated with pollution.

Considerations of the impacts on health of water pollution have focused on waterborne illnesses like diarrhea because the problem contributes to about 70–80% of the health problems

in most developing countries (Chabala and Mamo 2001). In the Philippines, waterborne illnesses remain a leading cause of morbidity and mortality in the country. Every year, 770,000 cases are reported nationwide (Department of Health 2000).

This study aims to assess whether the drinking water quality parameters: sensory examination, pH, physico-chemical (i.e. Nitrate and iron) and bacteriological examination for fecal coliform are significantly different between the communities with and without the dumpsite. It aims to determine whether pollution in the dumpsite produces a significant health impact on the communities, particularly water-borne disease related symptoms, and to correlate the site-specific prevalence of these reported cases of symptoms cases with that of the drinking water quality water parameters stated above.

The results of this study would yield information regarding the quality of water there is in the 3 randomly selected point sources in Brgy. Pakiad, Oton, Iloilo and in the 3 randomly selected point sources in Brgy. Calajunan, Madurriao, Iloilo City and their differences in terms of water quality and occurrence of common waterborne diseases. This would give baseline data for the future regarding the implications and impacts of the presence of an open dumpsite compared to a place with no presence of it.

MATERIALS AND METHODS

The experiment used a descriptive research design. Standard procedures in microbiology and in analytical chemistry were used in determining the presence or absence of fecal coliform (Escherichia coli content) and physico-chemical properties of the water sample, respectively. An interview with the respondents from both sites was conducted to describe the type of the symptoms they have experienced before.

A. Description of the Study Area

The study aimed to compare the quality of drinking water in Brgy. Calajunan, Mandurriao with that of Brgy. Pakiad, Oton. Brgy.Calajunanis located in the western part of Mandurriao which borders the municipality from Oton. The total population of Brgy.Calajunan is 2, 953 (as of August, 2007). It serves as a depository site for the garbage collected around the city of Iloilo. Brgy. Pakiad is the barangay next to Brgy. Calajunan. It is located in the western part of Oton and has total population of 3, 156. It is the control site for the study since it has relatively similar characteristics with Brgy. Calajunan except that it doesn’t have a dumpsite. For each of the barangay, three point sources were selected and water samples were collected from each of them. The water collected from each of the point sources were then subjected to water analysis.

B. Sample Collection and Transport

All water samples from the point sources for both barangays (Pakiad and Calajunan) were collected last May 8, 2012 between 6:00 to 8:00 in the morning. For each of the point sources sterile bottles were used to contain the water collected. Sensory examination was done immediately upon collection of the sample. After the sampling, samples were kept in buckets with ice and were transported immediately to the UPV Botany Laboratory Room for analysis proper.

C. Measurement of Physico-chemical characteristics

1. pH

pH of the water samples were determined usinga pH meter. This was done in three replicates per water sample.

2. Total Dissolved Solids (TDS)

Crucibles were prepared for weighing. The clean crucibles were then heated to 180+2C for 1 hour in an oven. They were stored in a desiccator until needed. Before use, the crucibles were weighed. A sufficient volume of sample was filtered using quantitative filter paper. A 20 mL filtrate was then transferred to a pre-dried and pre-weighed crucible and was evaporated to dryness on a steam bath (or in an oven). Evaporation was continued several times until at least 100 mL filtrate had been evaporated. Then, the residue was dried to constant weight. This whole process was done in three replicates.

3. Iron Content Determination

In determining iron in a water sample, the standard iron solution was pipetted into five 100-mL volumetric flasks with 1-, 5-, 10-, 25-, and 50-mL portion, respectively. A blank of 50mL of distilled water in another flask was needed. Different reagents were then added to each flask. These reagents were 1 mL of the hydroxylamine hydrochloride solution, 10 mL of the 1, 10 – phenanthroline solution, and 8 mL of the sodium acetate solution. Then, all the solutions were diluted to their respective 100-mL marks and were allowed to stand for 10 minutes.

Using the 508 nm wavelength, the absorbance of each of the standard solutions and the water sample were measured. Then, the absorbance vs. the concentration of the standards was plotted. From the absorbance of the water sample, the concentration of iron (mg/liter) was calculated.

4. Nitrate Content Determination

Standards were prepared by drying about 10g potassium nitrate at 105°C for two hours. It was then cooled in a desiccator. 1000 µg/mL NO3--N stock solution was then made by dissolving 7.223 g dry potassium nitrate in water in a 1000 mL volumetric flask. From the said stock solution, 25 mL was transferred into 500 mL volumetric flask and was filled with water up to the mark. This was the 50 µg/mL NO3--N stock solution. 0, 2, 4, 6, 8 and 10 mL of the 50 µg/mL NO3--N stock solution were transferred into corresponding 50 mL volumetric flasks and were filled with water up to the mark as well. Concentration of each prepared standard solution was then calculated.

From the prepared standards and samples, 0.5 mL was measured into suitably marked test tubes. Each test tube was added with 1.0 mL of salicylic acid solution, mixed well immediately after the acid had been added and left for 30 minutes. 5% salicylic acid was prepared by dissolving 5g salicylic acid in 95 mL concentrated sulfuric acid.

Then, 10.0 mL of NaOH solution was also added to each test tube, mixed well and left for one hour for full color development. 4M NaOH was prepared by dissolving

160g in 1000 mL distilled water. Absorbance of each standard and sample was read at 410 nm.

D. Determination of Fecal coliform contenta. Presumptive Coliform Test

Fermentation tubes were arranged in rows. From the undiluted sample, 5 x 10 mL were taken and inoculated into 5 x 10 double strength LT broth, followed by inoculation of 5 x 1 mL of the same sample and 5 x 1 mL of a tenfold dilution of the sample into 10 mL volumes of single strength broths. Inoculated tubes were inoculated at 30°C or 37°C for up to 48 hours. Lactose fermentation was evidenced by gas production that was detected by the inverted Durham tube that collected gas evolved in the broth. LT broths producing gas were regarded as presumptive coliforms.

b. Confirmed Coliform Test

Inocula from the positive LT broths were taken out and streaked into Eosin Methylene Blue (EMB) agar for confirmation. Plates were then incubated at 30°C for 18-24 hours. Typical coliform form black colonies on EMB agar or dark centered colonies with transparent colorless peripheries. Coliform concentration was determined in reference to MPN tables.

E. Determination of Incidence of Health Risk

A total of 100 (using Slovin’s formula) respondents from each barangay were selected for the interview of the study using purposive convenience sampling. They were interviewed last May 12, 2012 after signing informed consent forms. The interview questions included the frequency they drink water from the selected point sources and the symptoms they have experienced from the past.

F. Statistical Tool

Data collected were analyzed using SPSS and Microsoft Excel. For the physico-chemical characteristics, means and standard deviations were determined and One-Way ANOVA was employed to determine if there is a significant difference in the quality of the drinking water between Brgy. Calajunan and Brgy. Pakiad. In addition, Chi-square test was used to determine the possible relationships among the variables on the incidence on the health risks.

RESULTS AND DISCUSSIONA. Sensory Examination

Immediately after the collection of the water samples from both barangays, they were subjected to sensory examination to avoid recording changes in the observable characteristics of the water sample.

Table 1. Results of Sensory Examination of the Water Samples from Brgy. Pakiad, OtonSample Smell Color Taste

A Odorless Colorless TastelessB Odorless Colorless TastelessC Odorless Colorless Tasteless

Table 2. Results of Sensory Examination of the Water Samples from Brgy. Calajunan, MandurriaoSample Smell Color Taste

X Weak Colorless MetallicY Weak Colorless MetallicZ Weak Colorless Metallic

The sensory properties of water are a combination of its chemical content and responses of a person’s senses. Personal preferences for drinking water are based on both psychological and physiological factors. Psychological factors include personal experience, memory, and external stimuli; physiological factors include biochemistry, physical body factors, health, and external factors such as humidity, temperature, etc.

Flavor is composed of tastes (sour, sweet, salty, bitter, umami), mouth feel, and odors that are either inhaled directly by the nose or are directed to nasal cavities through the back of the mouth. Although consumers generally expect their water to have little or no flavor, people can detect variations in pH, mineral, and organic content of drinking water. The perception of drinking water taste is relative to one’s saliva. Sources of flavor includes: (1) the chemical and microbial content of the natural water, which is most influenced by geology and ecology; (2) chemicals added or removed during treatment and (3) inputs and reactions that occur during distribution and storage.

Individual taste and odor compounds which result in sensory response can occur in concentrations from pg/L to mg/L. Although it is hard to generalize, certainly many nuisance organic odorants in water are present at mg/L concentrations, while many mineral species evoke a taste at mg/l concentrations. The intensity and descriptors of odors can vary with concentration and temperature.

Turbidity in water may be due to presence of colloidal constituents. The health effects related to the taste of drinking water are thus indirect. Adverse tastes may cause the consumer to prefer an unsafe source; careful treatment to minimize non-specific tastes, however, can be expected to pay dividends by controlling other parameters, such as turbidity, which have a more direct influence on public health.

B. Determination of pH

One way to assess the physico-chemical characteristics of the water is to determine the pH value. The pH of the water sample was measured with the use of the precalibrated pH meter.

Table 3. pH of the Water Samples from Brgy. Pakiad, Oton Sample A pH Average

Replicate1 6.74

6.62 ± 0.142 6.643 6.47

Sample B pH Average

Replicate1 6.31

6.49 ± 0.162 6.613 6.55

Sample C pH Average

Replicate1 5.86

5.91 ± 0.052 5.963 5.91

Table 4. pH of the Water Samples from Brgy. Calajunan, Mandurriao Sample X pH Average

Replicate1 6.35

6.60 ± 0.222 6.783 6.65

Sample Y pH Average

Replicate1 6.15

6.21 ± 0.062 6.273 6.21

Sample Z pH Average

Replicate1 6.48

6.68 ± 0.182 6.753 6.82

Table 5. Results for the Statistical Analysis of the pH of the Water SamplesSamples Analyzed P-value (ά= 0.05)

A vs XYZ 0.02605B vs XYZ 0.037288

C vs XYZ 0.000692X vs ABC 0.001504Y vs ABC 0.000245Z vs ABC 0.000537

The pH (power of hydrogen) of the water reflects with it is acidic or basic. The pH depends upon the [H+] or [OH-] in the water. All the pH range is in compliance with the pH standard imposed by the DENR except sample C. pH is classified as a secondary drinking water contaminant whose impact is considered aesthetic. According to DENR standards, the pH standard range is 6.5-8.5. It is also the pH range recommended by the U.S. Environment Protection Agency (EPA). Most of the drinking water has a neutral pH to slightly basic.

The pH of pure water (H2O) is 7 at 25oC, but when exposed to the carbon dioxide in the atmosphere this equilibrium results in a pH of approximately 5.2 (due to formation of carbonic acid). Because of the association of pH with atmospheric gases and temperature, it is strongly recommended that the water be tested as soon as possible. The pH of the water is not a measure of the strength of the acidic or basic solution and alone does not provide a full picture of the characteristics or limitations with the water supply.

The pH of water determines the solubility (amount that can be dissolved in the water) and biological availability (amount that can be utilized by aquatic life) of chemical constituents such as nutrients (phosphorus, nitrogen, and carbon) and heavy metals (lead, copper, cadmium, etc.). For example, in addition to affecting how much and what form of phosphorus is most abundant in the water, pH also determines whether aquatic life can use it. In the case of heavy metals, the degree to which they are soluble determines their toxicity. Metals tend to be more toxic at lower pH because they are more soluble.

Furthermore, excessively high and low pHs can be detrimental for the use of water. Water with low pH is considered to be acidic and not safe for human consumption. Acidic water is naturally soft and corrosive. Metals from the pipes and fixtures like copper, lead and zinc can be leached by acidic waters. It can also damage metal pipes and cause aesthetic problems, such as a metallic or sour taste, laundry staining or blue-green stains in sinks and drains. Water with a low pH may contain metals in addition to the before-mentioned copper, lead and zinc. Acidity or low pH of drinking water is usually a result of natural geological conditions at the site, possibly compounded by acid rain. Acidic water is harmful not only to human beings but even to animals as well.

In addition, drinking water with a pH level above 8.5 indicates that a high level of alkalinity minerals is present. High alkalinity does not pose a health risk, but can cause aesthetic problems, such as an alkali taste to the water that makes coffee taste bitter; scale build-up in plumbing; and lowered efficiency of electric water heaters. High pH causes water pipes and water-using appliances become encrusted with deposits, and it depresses the effectiveness of the disinfection of chlorine, thereby causing the need for additional chlorine when pH is high. Alkalinity comes from rocks and soils, salts, certain plant activities, and certain industrial wastewater discharges (detergents and soap-based products are alkaline).

Lastly, the pH of water samples from Pakiad (A, B, C) are each analyzed with those pH of the samples obtained from those samples obtained from Calajunan (X, Y, Z) and vice versa using the one way ANOVA with an alpha value of 0.05 as standard room for error. The p values obtained from the test were then compared to the alpha value. Results showed that all the P-values obtained in each analysis or tests are less than 0.05. This means that there is a significant difference in pH between the water samples obtained from Brgy. Pakiad and Brgy. Calajunan.

C. Total Dissolved Solids

The amount of the total dissolved solids in water sample was determined by evaporating the water sample (until dryness) in a pre-weighed crucible and getting the weight of the dried residue left.

Table 6. Weight of the total dissolved solids from the water samples in Brgy. Pakiad, Oton

A Crucible(pre weight)

Crucible (constant weight)

Crucible + residue

(pre weight)

Crucible + residue

(constant weight)

Residue

1 21.5526 21.5528 21.5975 21.5980 0.0452

2 22.7460 22.7455 22.7963 22.7965 0.0510

3 21.8889 21.8890 21.9385 21.9387 0.0497

Average 0.0488 ± 0.0031

BCrucible(pre

weight)

Crucible (constant weight)

Crucible + residue

(pre weight)

Crucible + residue

(constant weight)

Residue

120.2031 20.2026 20.2725 20.2729 0.0703

221.8142 21.8139 21.8898 21.8896 0.0757

322.7377 22.7372 22.8057 22.8062 0.0690

Average 0.0717 ± 0.0036

CCrucible(pre

weigh)Crucible (constant weight)

Crucible + residue

(pre weight)

Crucible + residue

(constant

Residue

weight)

122.2939 22.2940 22.3813 22.3818 0.0878

222.4485 22.4486 22.5245 22.5250 0.0764

321.0886 22.0891 21.1758 22.1760 0.0869

Average 0.0837 ± 0.0063

Table 7. Weight of the total dissolved solids from the water samples in Brgy. Calajunan, Iloilo

XCrucible(pre

weigh)

Crucible (constant weight)

Crucible + residue

(pre weight)

Crucible + residue

(constant weight)

Residue

121.0680 21.0683 21.8133 21.8138 0.7455

221.2040 21.2043 21.9107 21.9103 0.7060

321.1970 21.1974 21.2740 21.9524 0.7550

Average

0.7355 ± 0.0260

YCrucible(pre

weigh)

Crucible (constant weight)

Crucible + residue

(pre weight)

Crucible + residue

(constant weight)

Residue

119.6785 19.6781 19.7595 19.7600 0.0819

221.6697 20.6703 20.7788 20.7785 0.1082

320.0521 20.0524 20.1516 20.1513 0.0989

Average

0.0963 ± 0.0133

ZCrucible(pre

weigh)Crucible (constant weight)

Crucible + residue

(pre weight)

Crucible + residue

(constant

Residue

weight)

120.0101 20.0105 20.0604 20.0589 0.0484

220.9535 20.9540 20.9994 20.9989 0.0449

322.0642 22.0641 22.1054 22.1049 0.0408

Average

0.0447

Table 8. Results for the Statistical Analysis of the TDS of the Water SamplesSamples Analyzed P-value

A vs XYZ 2.12E-11B vs XYZ 2.37E-11C vs XYZ 2.8E-11X vs ABC 1.14E-11Y vs ABC 0.000403Z vs ABC 1.15E-05

Based on the results only sample A and sample Z are the only samples considered palatable based on the DENR’s established water quality standard of 500 mg/L which aims to provide palatability of drinking water. High TDS levels generally indicate hard water, which can cause scale build-up in pipes, valves, and filters, reducing performance and adding to system maintenance costs. These effects can be seen in aquariums, spas, swimming pools, and reverse osmosis water treatment systems. Aside that all of the water samples are considered to be fresh water as indicated by the works of Wendell in 2007, which classifies water according to TDS as in the following: fresh water if < 1500 mg/L TDS; brackish water if 1500-5000 mg/L TDS; saline water if > 5000 mg/L TDS.

Total Dissolved Solids (TDS) are the compounds in the water that cannot be removed by a traditional filter. It represents the total concentration of dissolved substances in water. TDS are made up of salts or compounds which dissociate in water to form ions. This means that a salt has two parts, one with a positive charge (cations) and one with a negative charge (anions), which separate and mix with the water (H2O) molecules. Common inorganic salts that can be found in water include calcium, magnesium, potassium and sodium, which are all cations, and carbonates, nitrates, bicarbonates, chlorides and sulfates, which are all anions.

TDS is used to estimate the quality of drinking water, because it represents the amount of ions in the water. Water with high TDS often has a bad taste and/or high water hardness, and could result in a laxative effect. The U.S. Environmental Protection Agency sets a secondary standard of 500 mg/L TDS in drinking water. Secondary standards are unenforceable, but recommended, guidelines for contaminants that may cause cosmetic or aesthetic effects in

drinking water. High TDS concentrations can produce laxative effects and can give an unpleasant mineral taste to water.

Minerals present in water can originate from a number of sources, both natural and as a result of human activities. Mineral springs contain water with high levels of dissolved solids, because the water has flowed through a region where the rocks have a high salt content. The water in the Prairie Provinces tends to have high levels of dissolved solids, because of high amounts of calcium and magnesium in the ground. These minerals can also come from human activities. Agricultural and urban runoff can carry excess minerals into water sources, as can wastewater discharges, industrial wastewater and salt that is used to de-ice roads.

When TDS levels exceed 1000mg/L it is generally considered unfit for human consumption. A high level of TDS is an indicator of potential concerns, and warrants further investigation. Most often, high levels of TDS are caused by the presence of potassium, chlorides and sodium. These ions have little or no short-term effects, but toxic ions (lead arsenic, cadmium, nitrate and others) may also be dissolved in the water. High TDS results in undesirable taste which could be salty, bitter, or metallic. It could also indicate the presence of toxic minerals. High TDS indicates hard water, which causes scale buildup in pipes and valves, inhibiting performance.

Lastly, TDS concentration of water samples from Pakiad (A, B, C) are each analyzed with those pH of the samples obtained from those samples obtained from Calajunan (X, Y, Z) and vice versa using the one way ANOVA with an alpha value of 0.05 as standard room for error. The p values obtained from the test were then compared to the alpha value. Results showed that all the P-values obtained in each analysis or tests are less than 0.05. This means that there is a significant difference in TDS concentration between the water samples obtained from Brgy. Pakiad and Brgy. Calajunan. Water samples from Calajunan relatively have a higher TDS concentration than water samples from Pakiad.

D. Physico-chemical Examination1. Colorimetric Determination of Nitrate

By determining the absorbance of the standard nitrate solutions (with known concentration) using spectrophotometer, the absorbance vs nitrate concentration curve was derived and from the equation of the line, the nitrate concentration of the water sample was determined as shown in Table 9.

Table 9. Determination of Nitrate in Water Samples Collected from Brgy. Pakiad, Oton and Brgy. Calajunan, Mandurriao

Solution Absorbance NO-3 Concentration (µg/ml)

Standards

0.00 0.040 0.002.0 0.115 2.004.0 0.205 4.00

(ml of Standard NO-3

6.0 0.265 6.008.0 0.390 8.0010 0.470 10.0

Blank 0.00 0.00

W

A

T

E

R

S

A

M

P

L

E

Pakiad,Oton

A

1 0.040 0.422 0.050 0.883 0.040 0.42

Average 0.58 ± 0.13

B

1 0.110 2.22 0.100 2.23 0.090 2.8

Average 2.2 ± 0.20

C

1 0.063 1.52 0.050 0.883 0.040 0.42

Average 0.92 ± 0.27

Calajunan, Mandurriao

X1 0.060 1.32 0.080 2.23 0.090 2.8

Average 2.2 ± 0.36

Y

1 0.140 5.02 0.140 5.03 0.120 4.2

Average 4.8 ± 0.23

Z

1 0.090 2.82 0.120 4.23 0.100 3.2

Average 3.4 ± 0.36

Legend:A, B, C- Brgy. Pakiad Point Sources 1, 2, and 3 respectivelyX, Y, Z- Brgy. Calajunan Point Sources 1, 2, and 3 respectively

0 2 4 6 8 10 120

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

f(x) = 0.0433571428571429 x + 0.0307142857142857R² = 0.992842995917598

Absorb...

[NO-3] (µg/ml)

Abso

rban

ce

Figure 1. Absorbance vs NO-3 Concentration curve of the Standard Solutions

Concentration of nitrate was determined from the three point sources collected from Brgy. Pakiad, Oton, Iloilo. Mean [NO-

3] (µg/ml) obtained were: 0.58 ± 0.13; 2.2 ± 0.20and 0.92

± 0.27from point source 1, 2, and 3 respectively. It is notable that results obtained for the water samples are still in compliance with the standards imposed by the DENR, which is 50µg/ml (maximum nitrate level). In contrast, nitrate concentration obtained from analysis of the drinking water samples from three point sources of Brgy. Calajunan were higher except for one point source. Mean [NO-

3] (µg/ml) obtained were: 2.2 ± 0.36; 4.8 ± 0.23 and 3.4 ± 0.36 from point source 1, 2, and 3 respectively. Although these values are higher compared to those obtained from Brgy.Pakiad, they still remain in the safe range based on the standards set by DENR. However, U.S. EPA recommends that, water quality standards for human consumption is set at ten milligrams of nitrate-nitrogen per liter of water (10 mg/L NO3

--N). This level of nitrate-nitrogen is equivalent to 45 mg/L of nitrate (NO3

-). Beyond 40mg/L NO3- can cause

methemoglobinemia in infants under six months.

Nitrate and nitrite are naturally occurring ions that are part of the nitrogen cycle and are ubiquitous in the environment. Both are products of the oxidation of nitrogen (which comprises approximately 78% of the earth’s atmosphere) by microorganisms in plants, soil or water. Nitrate is the more stable form of oxidized nitrogen but can be reduced by microbial action to nitrite, which is moderately chemically reactive. Chemical and biological processes can further reduce nitrite to various compounds or oxidize it to nitrate. Nitrate salts are used widely as inorganic fertilizers, and are also used in explosives, as oxidizing agents in the chemical industry and as food preservatives. Nitrite salts have been also used as food preservatives, especially to cure meats (Environmental Protection Agency, 1987; Health Canada, 1992; Pokorny et al., 2006). The content of nitrite in groundwater or surface water is generally negligible compared with that

of nitrate. However, under anaerobic conditions, nitrate may be converted to nitrite through microbacterial contamination (Health Canada, 1992).

Nitrate contamination of potable water sources is becoming one of the most important water quality concerns in the United States. The maximum contaminant level (MCL) for nitrate is 10 mg/L as nitrogen (N). The major health concern of nitrate exposure through drinking water is the risk of methemoglobinemia, or “blue baby syndrome,” especially in infants and pregnant women. Due to the nature of the infant digestive system, nitrate is reduced to nitrite which can render hemoglobin unable to carry oxygen (SWRCB, 2010). Nitrate is naturally occurring at low levels in most waters, but it is particularly prevalent in groundwater that has been impacted by certain agricultural, commercial or industrial activities. Of specific concern are crop fertilization activities and discharges from animal operations, wastewater treatment facilities, and septic systems. Small rural communities are particularly impacted by nitrate (Pacific Institute, 2011). The main diffuse sources of contamination of surface water are agricultural run-off, drainage from roads and suburban lawns, and nitrogen transported by rain (Graffy et al., 1996).

One of the main reasons why there is higher nitrate concentration in water samples collected from Brgy. Calajunan is fertilizer contamination due to the presence of farmlands in the vicinity where samples were collected. Application of fertilizer in excess of the amount not taken up by crops leads to leaching into the groundwater. Leakage from livestock feedlots and waste storage also contributes to the nitrate problem (LLNL, 2002). Additional sources include wastewater treatment discharge, faulty septic systems and various industrial applications. Due to the typical sources, nitrate contamination is more common in rural agricultural areas. The major health concern of nitrate exposure through drinking water is the risk of methemoglobinemia, especially in infants and pregnant women (SWRCB, 2010).

In contrast, minimal nitrate concentration detected from the water samples of Brgy. Pakiad, Oton, Iloilo might have been due to natural occurrence of nitrate and nitrite in soil results from microbial oxidation of ammonia which is derived from organic nitrogenous material such as plant proteins, animals and animal excreta (WHO, 1978). The background concentration of nitrate in sources of water in the USA is very low, and is generally less than 2 mg/L nitrate-N in groundwater and less than 0.6 mg/L in streams. Higher levels of nitrate are found in contaminated sources, and especially in groundwater (Mueller & Helsel, 1996). Also, water sample collected from point source B although have a safe nitrate concentration has an appreciably higher value compared to others. This might be because the point source is located near a pig pen and a chicken coop, which may have caused contamination. Point sources A and C on the other hand are properly covered, far from farm lands, roads, or animal/livestock cages.

Table 10. Statistical Analysis of the Water Sample collected from two barangays andthree different point sources

Comparison P- valueA vs X,Y,Z 0.000904B vs X,Y,Z 6.28 x 10-6

C vs X,Y,Z 0.000190X vs A, B, C 0.000131Y vs A, B, C 0.00485X vs A, B, C 0.000391

All the samples collected from both barangays are significantly different from each other with the nitrate concentration higher in Brgy. Calajunan compared to Brgy. Pakiad.

2. Determination of Iron, with 1, 10 Phenanthroline

To further assess the physico-chemical characteristics of the obtained water sample the iron content was determined with the use of 1, 10-Phenanthroline. Through the use of spectrophotometer, the absorbance of the water sample was measured and the Iron concentration was computed.

0 5 10 15 20 25 300

0.2

0.4

0.6

0.8

1

1.2

f(x) = 0.040140579064588 x + 0.0134339420935413R² = 0.995537196217205

Absorbance of Solutions of Different Iron Concentrations at 508 nm

Absorbance of Solutions of Different Iron Concentra-tions at 508 nmLinear (Absorbance of So-lutions of Different Iron Concentrations at 508 nm)

Figure 2. Linear Graphical Representation and Equation on the Relationship Between the Prepared Solution Standards of Different Concentrations and Their Absorbances at 508 nm

Wavelength for Iron Determination of Point Sources A, B, C and X.

0 2 4 6 8 10 12 140

0.1

0.2

0.3

0.4

0.5

0.6

f(x) = 0.0439353905496625 x − 0.00233510125361619R² = 0.997743237111479

Absorbance of Solutions of Different Iron Concentrations at 508 nm

Absorbance of Solutions of Different Iron Concentra-tions at 508 nmLinear (Absorbance of So-lutions of Different Iron Concentrations at 508 nm)

Figure 3. Linear Graphical Representation and Equation on the Relationship Between the Prepared Solution Standards of Different Concentrations and Their Absorbances at 508 nm

Wavelength for Iron Determination of Point Sources Y and Z.

Table 11. Results of the Determination of the Iron Concentration of the Obtained Water Samples.

Location Water Point

Source

Replicate Absorbance Iron Concentration

(mg/L)

Water Point Source Average Iron

Concentration (mg/L)

Brgy. Pakiad

A 1 0.002 0.098 0.087 ± 0.016

2 N. D. N. D.

3 0.001 0.075

B 1 0.011 0.303 0.303 ± 0.046

2 0.013 0.349

3 0.009 0.257

C 1 0.009 0.257 0.257 ± 0.023

2 0.010 0.280

3 0.008 0.235

Brgy. Calajuna

n

X 1 0.031 0.759 1.192 ± 0.44

2 0.070 1.647

3 0.049 1.169

Y 1 0.017 0.090 0.123 ± 0.038

2 0.020 0.165

3 0.018 0.115

Z 1 0.014 0.015 0.118 ± 0.075

2 0.018 0.115

3 0.017 0.090

Iron can be a troublesome chemical in water supplies. Making up at least 5 percent of the earth’s crust, iron is one of the earth’s most plentiful resources. Rainwater as it infiltrates the soil and underlying geologic formations dissolves iron, causing it to seep into aquifers that serve as sources of groundwater for wells. Although present in drinking water, iron is seldom found at concentrations greater than 10 milligrams per liter (mg/L) or 10 parts per million. However, as little as 0.3 mg/l can cause water to turn a reddish brown color. Iron is mainly present in water in two forms: either the soluble ferrous iron or the insoluble ferric iron. Water containing ferrous iron is clear and colorless because the iron is completely dissolved. When exposed to air in the pressure tank or atmosphere, the water turns cloudy and a reddish brown substance begins to form. This sediment is the oxidized or ferric form of iron that will not dissolve in water. Iron is not hazardous to health, but it is considered a secondary or aesthetic contaminant. Essential for good health, iron helps transport oxygen in the blood. Most tap water supplies approximately 5 percent of the dietary requirement for iron. Dissolved ferrous iron gives water a disagreeable metallic taste. When the iron combines with tea, coffee and other beverages, it produces an inky, black appearance and a harsh, unacceptable taste. Vegetables cooked in water containing excessive iron turn dark and look unappealing. Concentrations of iron as low as 0.3 mg/L will leave reddish brown stains on fixtures, tableware and laundry that is very hard to remove. When these deposits break loose from water piping, rusty water will flow through the faucet. When iron exists along with certain kinds of bacteria, a smelly biofilm can form. To survive, the bacteria use the iron, leaving behind a reddish brown or yellow slime that can clog plumbing and cause an offensive odor. This slime or sludge is noticeable in the toilet tank when the lid is removed. The organisms occur naturally in shallow soils and groundwater, and they may be introduced into a well or water system when it is constructed or repaired. Iron can combine with different naturally-occurring organic acids or tannins. Organic iron occurs when iron combines with an organic acid. Water with this type of iron is usually yellow or brown, but may be colorless. As natural organics produced by vegetation, tannins can stain water a tea color. In coffee or tea, tannins produce a brown color and react with iron to form a black residue. Organic iron and tannins are more frequently found in shallow wells, or wells under the influence of surface water. For these reasons, the DENR through the Philippine National Standards for Drinking Water sets Iron Concentration for drinking water should not be greater than 1 mg/L.

Iron reacts with 1,10-phenanthroline to produce the complex [Fe(phen)3]2+, called "ferroin," is used for the photometric determination of Fe(II). Figures 2 and 3 show the results and the lines and their equations of the relationship between the prepared solution standards of different concentrations and absorbance at 508 nm wavelength. The best line possible was utilized by omitting outlying points such that the R2 value of the linear equation was made to be close to the value of 1 as much as possible while maintaining at least 3 points in the graph. Table

5 shows the results of the determination of the iron concentration of the obtained water sample. As seen in Table 5, point source X was the only point source water sample to exceed the standard set by the DENR with an iron concentration of 1.192 ± 0.44. Around point source X, there were piles of uncollected junks near the point source, such as pipes, galvanized iron sheets, bike tubes, etc. and wide pools of stagnant water, which are ~2m – 6m in diameter, which may explain why point source X water sample had an iron concentration that went far beyond the iron concentration of the other samples. The other samples, having values within the normal range as set by the DENR, may have so because of the natural processes happening in the dissolution and percolation of ground iron. Also, as seen in Table 6, each of the sample from the 2 different barangays have iron concentrations that are significantly different (p<0.05) from the water sample coming from point sources from the other barangay. The significant difference may be due to the presence of piles of garbage and wastes having iron in the dumpsite in Brgy. Calajunan which led water samples in this barangay to have a significantly higher iron concentration from those of the water samples from Brgy. Pakiad.

E. Bacteriological Examination (Fecal coliform: Multiple Tube Fermentation Technique)

Fecal coliform was determined by multiple tube fermentaion technique. The test tubes with lactose tryptose broth were then checked for gas formation which indicates fermentation by the bacteria present in the sample and turbidity which means bacterial growth in the media. The results of this experiment are shown in Table 13.

Table 12. MPN Index of Water Samples Collected

Point SourceNumber of Positive Tubes MPN Index

(per 100 ml)DSLB SSLB undiluted

SSLB diluted

Pakiad A 3 3 0 2.4B 3 3 0 2.4C 3 3 0 2.4

Calajunan X 4 3 0 27Y 4 2 0 22z 3 3 0 2.4

Coliform bacteria are found in the digestive system and pass through in the waste of human beings and warm-blooded animals. They are not general pathogens but serve as indicators to show that disease bacteria may be present and that treatment or corrective measures should be taken (Nwachukwu and Otokunefor, 2006). Furthermore, the use of normal intestinal organisms as indicators of fecal pollution is universally accepted for monitoring and assessing the micro-biological safety of water supplies (Dissanayake et al., 2004).

Tests for coliform may be carried out using either the multiple-tube fermentation technique or the membrane filter technique. The multi-tube fermentation procedure involves three test phases called the presumptive, the confirmed, and the completed test. The presumptive test is based on the ability of coliform bacteria to ferment lactose sugar broth, producing gas. The confirmed test consists of growing cultures of bacteria from the presumptive medium that suppresses the growth of other organisms. The completed test is then based on the ability of the cultures to again ferment lactose broth. This test is very specific for coliform.

The results of the experiment showed that some tubes are positive for gas formation which indicates lactose fermentation by the bacteria and along with it is observed turbidity in the tubes. However, when these samples where grown into EMB Plate, none exhibited green metallic sheen. This result indicates that the presence lactose fermenting bacteria but cannot grow in EMB Plate. Examples of these bacteria are Enterobacter, Citrobacter and Klebsiella. These bacterial genera are lactose fermenters but not fecal in origin. Since there is no growth in the EMB Plates, it indicates that no coliform bacterium is present in the water sample. MPN indices of all the water samples were in violation with the DENR standard which is an MPN index ) per 100 mL.

F. Health Risk Assessment

Of all the diseases surveyed in both barangays, only typhoid fever, amoebiasis and ascariasis were reported. Part of the survey also was to gather data on the symptoms associated with waterborne diseases. Table 13 shows the frequency distribution of the results of the survey.

Table 13. Frequency Distribution of Waterborne Diseases and Associated Symptoms.Location Symptomatic Typhoid Fever Ascariasis Amoebiasis

Yes No Total Yes No Total Yes No Total

Yes No Total

Brgy. Calajunan

81 19 100 8 92 100 14 86 100 29 71 100

Brgy. Pakiad

9 91 100 2 98 100 2 98 100 0 100 100

As analyzed using the chi-squared test for independence, there was a significantly higher occurrence of waterborne disease-associated symptoms (p=0.00<0.05), typhoid fever (p=0.00<0.5), ascariasis (p=0.00<0.05) and amoebiasis (p=0.00<0.05) in Brgy. Calajunan compared to Brgy. Pakiad. The results of the survey coincided with the bacteriological test results wherein there was higher MPN index in Brgy. Calajunan’s water samples than in Brgy. Pakiad’s water samples.

CONCLUSION

Water quality is determined by assessing three classes of attributes: biological, chemical, and physical. Primary drinking water standards regulate organic and inorganic chemicals, microbial pathogens, and radioactive elements that may affect the safety of drinking water. Secondary standards, on the other hand, regulate color, iron, odor, pH, total dissolved solids, and nitrates, among others, all of which may affect qualities of drinking water like taste, odor, color, and appearance.

pH of water samples from both barangays are relatively the same, but Brgy. Pakiad has somehow lower pH. All except one water sample were in accordance with the DENR standard. TDS concentration of water samples from Brgy. Calajunan is higher than that of Brgy. Pakiad. Samples B, C, X and Y exceeded the limit of 500 mg/L. All samples collected from both barangays were within the standards of DENR in terms of [NO -

3]. Nitrate concentration was higher in Brgy. Calajunan than in Brgy. Pakiad. [NO-

3] obtained from both barangays were significantly different from each other. Furthermore, there was a significant difference in iron concentration between water samples regardless of the place from where they are collected (Pakiad or Calajunan). MPN indices for both barangays exceed the DENR standards but the MPN index of Brgy. Calajunan is higher than that of Brgy. Pakiad. High bacteriological count in Brgy. Calajunan correlated with the high occurrence of water-borne disease-related symptoms and diseases.

CALCULATIONS

pH

Samples from 3 Point Sources in Brgy. Pakiad, Oton

Sample A

Ave= 6.74+6.64+6.47

3=6.62

Sd= √ (6.74−6.62)2+(6.64−6.62)2+ (6.47−6.62 )2

2=± 0.14

Sample B

Ave= 6.31+6.61+6.55

3=6.49

Sd= √ (6.31−6.49)2+(6.61−6.49)2+ (6.55−6.49 )2

2=± 0.16

Sample C

Ave= 5.86+5.96+5.91

3=5.91

Sd= √ (5.86−5.91)2+(5.96−5.91)2+ (5.91−5.91 )2

2=± 0.05

Samples from 3 Point Sources in Brgy. Calajunan, Mandurriao

Sample X

Ave= 6.35+6.78+6.65

3=6.60

Sd= √ (6.35−6.60)2+(6.78−6.60)2+(6.65−6.60 )2

2=± 0.22

Sample Y

Ave= 6.15+6.27+6.21

3=6.21

Sd= √ (6.15−6.21)2+(6.27−6.21)2+(6.21−6.21 )2

2=± 0.06

Sample Z

Ave= 6.48+6.75+6.82

3=6.68

Sd= √ (6.48−6.68)2+(6.75−6.68)2+(6.82−6.68 )2

2=± 0.18

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