1. June 2012, Volume 3, No.3
International Journal of Chemical and Environmental Engineering
Determination of Some Heavy Metals Possibly
Present in Drinking Stations Found in the Vicinity
of a University in Manila, Philippines
M. Castañedaa
, M. Datuinb,
M. J. Jardineroa
, C. H. Mendozab
, J. Rodriguezb
, M. Umalib
, J. Solidumc*
a
SALIKASAN Researcher and BS Pharmacy, University of the Philippines, Manila, Philippines
b
BS Pharmacy, College of Pharmacy, University of the Philippines, Manila, Philippines
c
Associate Professor IV, College of Pharmacy and Director of Sentro ng Wikang Filipino,University of the Philippines,
*Corresponding author E-mail: graloheus@yahoo.com - crea_joie@yahoo.com
Abstract:
Toxic heavy metals in air, soil and water are global problems that pose threat to the environment. Heavy metals are natural
components of the Earth's crust. Harmful concentrations of many dissolved heavy metals are often found in groundwater destined for
potable drinking water. These contaminations are both naturally occurring contaminations as well as industrially-introduced pollution.
The student researchers conducted a descriptive-exploratory analysis of water coming from student-accessible drinking stations in the
different colleges in a well-known university in Manila, Philippines. These water samples were acid digested and were qualitatively
and quantitatively tested for the heavy metals possibly present. Qualitative testing of the sampled water yielded negative results.
Quantitave testing of the sampled water for lead and cadmium, however, resulted to concentrations higher than the standard limit for
drinking water set by the Environmental Protection Agency (EPA). It was shown in this study that water from these sources are not
safe for drinking due to higher than normal levels of lead and cadmium. Both metals are known to be harmful toxicants that may
adversely affect the students and other constituents of the aforementioned university.
Keywords: Drinking fountain; heavy metals; water; lead intoxication; cadmium intoxication; school; university; students; toxicity
1. Introduction
Toxic heavy metals in air, soil and water are global
problems that pose threat in the environment. Heavy
metals are natural components of the Earth's crust. To a
small extent they enter our bodies via food, drinking
water and air. Heavy metal poisoning could result, for
instance, from drinking-water contamination (e.g. from
lead pipes), high ambient air concentrations near emission
sources, or intake via the food chain [1].
Abbasi and his colleagues quoted, “A pollutant is nothing
but a misplaced resource” [2]. Metals have many
applications today – in common household items, in
farming, travel, communication, pharmaceutical industry,
food industry, etc. Metals and metalloids are ubiquitous
[3]. Metals cannot be broken down to non-toxic forms.
Once they have contaminated the ecosystem, they would
remain potential threat for many years.
In small quantities, some heavy metals are nutritionally
essential for a healthy life, but large amounts of any of
them may cause acute or chronic toxicity or poisoning.
Trace elements such as iron, copper, manganese, and zinc
are commonly found naturally in foods we consume or as
part of a vitamin supplement. The metals most often
linked to human poisoning have links to learning
disabilities; cancers and death are typically copper, nickel,
cadmium, chromium, arsenic, lead and mercury. Heavy
metal toxicity can result in damaged or reduced mental
and central nervous function, lower energy levels, and
damage to blood composition, lungs, kidneys, liver, and
other vital organs[4].
Harmful concentrations of many dissolved heavy metals
are often found in groundwater destined for potable
drinking water. These contaminations are both naturally-
occurring contaminations as well as industrially-
introduced pollution. The concentration of any of these
contaminants creates health concerns ranging from very
mild to severe. Increased urbanization and water demand
in areas of industrial activity, such as the National Capital
Region (NCR) where the university understudy is located,
has increased the frequency of problem metals in
groundwater sources [5].
The researchers were concerned of the contamination of
drinking water with lead and cadmium. The primary
source of lead in most drinking water is the piping (lead
fitting or solder) used for its distribution. Most colleges in
the university have drinking fountains as their drinking
water source. Maintenance of this tube piping is

2. Determination of Some Heavy Metals Possibly Present in Drinking Stations Found in the Vicinity of a University in Manila, Philippines
154
necessary to prevent lead contamination of the water it
distributes. Contamination of drinking-water with
cadmium may occur as a result of the presence of
cadmium as an impurity in the zinc galvanized pipes or
cadmium-containing solders in fittings, water heaters,
water coolers, and taps [6].
Chronic lead intoxication includes anemia, calcium,
phosphorous and vitamin D deficiency and irreversible
lead nephropathy (chronic interstitial nephritis). Late
signs of lead intoxication from high levels manifest as
slowed nerve conduction and forearm extensor weakness
(wrist drop) [7].
The kidney is the principal organ targeted by chronic
exposure to cadmium. Data from human studies suggest a
latency period of approximately 10 years before clinical
onset of renal damage, depending on intensity of
exposure. Clinically significant bone lesions usually occur
late in severe chronic cadmium poisoning and include
pseudofractures -- spontaneous fractures that follow the
distribution of stress in normal skeleton or occur at sites
where major arteries cross the bone and cause mechanical
stress through pulsation [8].
Another condition related to Cadmium toxicity is Itai-itai
disease, which was first described in post-menopausal
Japanese women exposed to excessive levels of cadmium
over their lifetimes through their diet because the region
of Japan in which they resided was contaminated with
cadmium. Signs and symptoms of Itai-itai disease include
severe osteoporosis and osteomalacia with simultaneous
severe renal dysfunction, normochromic anemia and low
blood pressure and average urinary cadmium level in
these patients is 20-30 μg/g-creatinine of cadmium in
urine [8].
Water fountains, which are the freestanding or wall-
mounted chilled drinking water dispensers, have been in
use for almost a century. Water fountains are originally
developed to protect the public health and prevent people
from spreading infection through sharing a drinking cup
[9]. Some colleges in the university uses filtered water
coming from their buildings’ faucets and load this to
water dispensers. The students can possibly be intoxicated
by these heavy metals through drinking from these water
fountains or water dispensers. These drinking stations
(water fountain or water dispenser) are set-up in different
colleges in the university for access of students.
This study is significant to all constituents of the
university, especially the students to whom these water
stations are primarily for. The university is an old
institution in the Philippines. It has already celebrated its
100 years of existence. This means that with the old
building are old lead pipes. The university administrators
of the different colleges must be aware of the possible
effects of intoxication of heavy metals to the human body.
The presence of several heavy metals was determined.
The heavy metals qualitatively tested were Arsenic, Lead,
Mercury, Bismuth and Antimony. The heavy metals
quantitatively tested with Atomic Absorption
Spectroscopy were Lead and Cadmium. This study was
performed to examine the presence of possible toxicants
in drinking stations in the different colleges in this well-
known university in Manila that may affect humans
especially the students. Samples from different drinking
stations all over the university are examined for the
presence of these toxicants by means of several tests that
would provide data which will be able to assess of the
safety of the water.
2. Objectives
2.1. General
The general objectives of this study are: (1) to examine
drinking stations in the chosen well-known university in
Manila, qualitatively and quantitatively, for the presence
of certain heavy metals; (2) to determine the possible
heavy metals present in readily accessible drinking
stations found in different colleges in the university; and
(3) to assess the safety of water found in drinking stations
in the said university.
2.2. Specific
Specific objectives are: (1) to subject each of the water
samples collected to acid digestion and perform
qualitative tests and quantitative test (Atomic Absorption
Spectroscopy) on each of them; (2) to compare the results
between the qualitative and quantitative tests; and (3) to
compare the results of quantitative analysis to standard
EPA limits for specific heavy metals
3. Materials and Method
3.1. Equipments and Instrumentation
The Atomic Absorption Spectroscopy (AAS) model used
was Shimadzu SpectrAA 6300 and the test was conducted
in De La Salle University-Manila (DLSU-M).
3.2. Gathering of water samples
Drinking water samples were collected from seven (7)
different locations within the vicinity of the selected
university campus. One sample was taken from the
following colleges: College of Medicine (CM), College of
Nurcing (CN), College of Dentistry (CD), College of
Pharmacy (CP), and the Robinson’s Place Ermita Food
Court (FC). Two samples were taken from the College of
Arts and Sciences (CAS) since they have two drinking
fountains. CM, CN, CAS and Robinson’s Ermita FC have
water fountains as source of drinking water. CP and CD
have water dispensers as source of drinking water. The
selection of the sites of water sampling was based on the
likeliness that students would drink from the place. A
small water bottle (500-mL distilled water bottle) served
as the container for the said samples.
3.3. Digestion of Water Samples
The 7 samples were digested by addition of 5-mL Nitric
Acid to 100-mL of each samples carefully transferred in a
beaker. This was then allowed to evaporate to about
52.5mL. 3mL of Nitric Acid was further added, and
finally evaporated to 40mL and diluted to 50 mL.

3. Determination of Some Heavy Metals Possibly Present in Drinking Stations Found in the Vicinity of a University in Manila, Philippines
155
3.4. Chemical Qualitative Tests
Qualitative tests were performed to the 7 samples. Tests
for Lead, Mercury, Arsenic, Antimony and Bismuth were
performed as follows:
3.4.1Qualitative Tests for Lead
Addition of sulphuric acid with the 1-mL sample followed
by observation of the precipitate formed and testing of its
solubility to aqueous hydrochloric acid and aqueous nitric
acid (as well as warm aqueous sodium hydroxide and
aqueous ammonium acetate. Another test involved the
addition of potassium chromate solution and then noting
the colour of the precipitate then testing its solubility of
the precipitate to aqueous acetic acid and aqueous sodium
hydroxide. Using the hydrochloric acid test for lead,
1.0ml of the sample was added with 0.5ml cold, dilute
hydrochloric acid. The color of the precipitate and its
solubility in hot water (cool afterwards and note the
crystals formed) and concentrated hydrochloric acid was
checked. Using Hydrogen sulfite test for lead, 1.0ml of
slightly acidic sample solution was added to 0.5ml
Hydrogen Sulfide. The color of the precipitate formed
was observed. For sodium hydroxide test, 1.0ml of the
sample was added with 10% sodium hydroxide dropwise
until a precipitate forms. The color of the precipitate was
observed. Its reaction with excess reagent addition was
observed as well as after adding hydrogen peroxide. For
potassium iodide test for lead, 1.0ml of sample was added
to 0.5ml potassium iodide. The color of the precipitate
and the solubility of the precipitate with boiling water
(cool & observe the plates formed) was observed [10].
3.4.2Qualitative Tests for Mercury
1.0ml sample was added to 0.5ml dilute sodium
hydroxide. The color of the precipitate formed was noted.
Continuous adding of dilute sodium hydroxide dropwise
was done any visible reaction was noted. The solubility of
the precipitate with dilute hydrochloric acid was also
checked. Using potassium iodide test for mercury, 1.0ml
sample was added with potassium iodide solution
dropwise taking note the color of the precipitate. Addition
of excess reagent was performed to test solubility of the
precipitate. In Hydrogen Sulfide test for mecury, 1.0mL
sample was added with 0.5ml diluted hydrochloric acid
noting the color of the precipitate formed. Another test
was performed by adding 1.0mL dilute hydrogen sulfide
noting the color of the precipitate and checking the
solubility of the final precipitate with water, nitric acid,
sodium hydroxide and ammonium sulfide. The last test
for mercury was performed by adding Hydrochloric acid
to the sample and noting the color of the precipitate
formed. Addition of aqueous ammonium hydroxide and
the change in the color of the precipitate was performed
[10].
3.4.3Qualitative Tests for Arsenic
In the Hydrogen Sulfide test, 1.0 ml acidic sample was
added with 0.5 ml hydrogen sulfide. Precipitate formation
was observed. Addition of concentrated hydrochloric acid
to test the solubility of the precipitate was performed as
well as addition of hot concentrate nitric acid is added to
further test the solubility of the precipitate. Using Silver
nitrate test for Arsenic, 1.0 ml sample solution was made
neutral and followed by adding 0.5 ml silver nitrate and
observing the color of precipitate formed. The solubility
in both nitric acid and ammonia of the precipitate formed
was observed. Performing Gutzeit’s test, 1-2grams of
arsenic free zinc in a test tube was added 2-3 mL of dilute
sulphuric acid with 2-mL sample. A loosely plug cotton
was placed in the tube and then place a piece of filter
paper moistened with 20% silver nitrate solution on top of
the tube, the moistened filter paper was then observed for
changes [10].
3.4.4Qualitative Tests for Antimony
In the Hydrogen Sulfide Test for antimony, the samples
were strongly acidified with concentrated hydrochloric
acid. Hydrogen sulphide was added to the acidified
samples, and the color of the precipitate that would form
was observed. The solubility of the precipitate formed
was tested with warm concentrated hydrochloric acid and
sodium hydroxide. For the Sodium Hydroxide Test, 10%
sodium hydroxide was added to the sample and the color
of the precipitate formed was observed. Potassium Iodide
Test was also performed on the samples. Potassium iodide
solution was added to the sample. The color of the
resultant solution was observed. And lastly, the Gutzeit’s
Test was performed on the samples. The color of the spot
produced was noted and tested for its solubility in 80%
ethanol [10].
3.4.5Qualitative Tests for Bismuth
To the samples, nitric acid was added. the solution was
diluted with water. The color of the precipitate formed
was noted. Ammonium sulphide was added to the
precipitate and to it, warm aqueous nitric acid was added
to check for solubility. Hydrogen Sulfide Test was
performed on the samples. To the samples, hydrogen
sulphide was added. The color of the precipitate formed
was noted. The solubility of the formed precipitate was
tested with cold, dilute hydrochloric acid, ammonium
sulphide, coiling hydrochloric acid and hot nitric acid.
Sodium Hydroxide Test was also performed. 10% sodium
hydroxide was added to the samples. The color of the
precipitate was observed and its solubility was tested with
dilute hydrochloric acid. To the original precipitate, 4-6
drops of concentrated hydrogen peroxide was added and
the color of the precipitate formed was noted. Last test
that was performed on the samples was the Potassium
Iodide Test. Potassium iodide was added dropwise to the
samples until a precipitate was observed. Excess
potassium iodide was added and the reaction was noted.
The reaction when water was added was noted. The
solution was heated and observed for the reaction [10].

4. Determination of Some Heavy Metals Possibly Present in Drinking Stations Found in the Vicinity of a University in Manila, Philippines
156
3.5. Chemical Quantitative Test
Four standards were used for the quantitative
determination of the concentrations of lead and cadmium
in each water sample. Atomic Absorption Spectroscopy
(AAS) from the Chemistry Laboratory of DLSU-M was
used. Although cadmium was not among the heavy metals
tested qualitatively, some studies found out that cadmium
levels in drinking stations were higher than the standard
values given by EPA and so this was also tested in the
AAS [11].
4. Results and Discussion
The results of the qualitative tests performed on the
samples for the determination of the heavy metals of
concern were all negative. This was expected since the
concentrations of lead and cadmium usually found in
water are very small (in ppm) for qualitative
determination. It should also be considered that the
stations from where the samples were obtained were
assumed to have employed some sort of filtering or water
treatment prior to distribution to faucets or to drinking
fountains. In the case of CP and CD, since their source of
drinking water for student consumption was delivered by
water dispenser, it should be expected that these waters
have been purified from the purifying water stations
wherein they were ordered.
For the quantitative analysis of heavy metals in the
samples, only concentrations of lead and cadmium were
tested. Table 1 shows the standard limits for lead and
cadmium set by the Environmental Protection Agency
(EPA) [11].
Table 1. Standard limits for Lead and Cadmium Set by
Environmental Protection Agency (EPA)
According to the EPA, the maximum allowable
concentration of the heavy metal Lead (Pb) in water is
0.015 ppm [epa]. Tables 2 and 3 summarize the results of
the quantitative examination done on the water samples.
For lead content, can be observed that the water samples
collected from drinking fountains and dispensers from the
different UP colleges and the Robinson’s Place Ermita FC
exceeded the standard concentration limit for lead
content. The lead concentration results as was determined
by the AAS for the samples ranged from 0.0614-0.2699
ppm which far exceeded the limit of 0.015 ppm.
The sample from the CD apparently had the highest
amount of Pb, 0.2699 ppm. The CD uses a water
dispenser. The researchers inquired the administration
office of the college about the age and the maintenance of
the said drinking station. It was found out that the water
dispenser was purchased the same year the new CD
building was opened, which was around 2002 or 2003.
Also, the college does not have a scheduled cleaning time
for its water dispenser. Moreover, the source of the water
was not always ordered outside the university. Most of
the time, it is just refilled from the faucet of the
Biochemistry Laboratory of the college. The researchers
also found out that the filtering device used to filter water
from the water tank prior to distribution to the whole
college was of a bag type. The filter is said to be cleaned
weekly, but the bag filter is of unknown age. Due to these
findings, it is not surprising that the lead concentrations
detected was high.
The average lead concentration of the sample obtained
from the CM has the least concentration, 0.0614 ppm.
The drinking fountain found in the CM Cafeteria is said
to be set up in 2006. The drinking fountain is checked and
cleaned monthly. However, although the cleaning is done
regularly, the water pipes connecting to it are old.
The results obtained from other water samples from the
other areas do not vary greatly with each other (sd=
0.0143) and from that sample with lowest amount of Pb
obtained (CM); but their values differ widely from the Pb
concentration of the sample with the highest amount of
the heavy metal (sd= 0.0665). The drinking water stations
from the other colleges are relatively newer compared to
the CD. CP purchased its water dispenser in 2009; the
CAS purchased and installed its drinking fountain in
2007, CN in 1997, and the Robinson’s Ermita FC around
2008. The filters of the drinking fountains from CAS are
cleaned every three months. The drinking fountain from
CN is cleaned three to four times a year and the water
from it tested negative for bacterial contamination when
sampled by the College of Public Health in 2010.
Cadmium (Cd) concentration levels were also tested from
the water samples. The EPA set the standard limit for Cd
to be 0.005 ppm, which was far exceeded by the values
obtained from the AAS analysis of the different water
samples. The levels of this heavy metal from the samples
ranged from 0.0870 to 0.0930 ppm (sd= 0.0019). It can be
seen from Table 3 that the water sample taken from the
water dispenser in CD contains the highest amount of Cd,
0.0930 ppm. The sample from the drinking fountain in the
quadrangle area of the CAS has the lowest levels of Cd,
0.0870 ppm. The concentration of Cd in the samples
taken from the other areas like CAS cafeteria, CM, CN,
CP and Robinson’s Ermita FC does not vary widely from
each other and from those with the highest and lowest
concentrations.
Standard Limits
Heavy Metal Water
Lead 0.015 ppm (EPA.gov)
Cadmium 0.005 ppm(EPA.gov)

5. Determination of Some Heavy Metals Possibly Present in Drinking Stations Found in the Vicinity of a University in Manila, Philippines
157
5. Conclusion and Recommendations
The results indicate an alarmingly high level of Pb and Cd
within the area where students from this well-known
university get their drinking water. These concentrations
exceeded the standard limit set by the EPA. Although the
results of the chemical qualitative tests performed were
negative, quantitative determination of certain (Pb and
Cd) heavy metals proved this. It is the concern of the
researchers to inform the constituents of the university
understudy, especially the administrators, of this
significant problem to prevent any or more severe clinical
manifestations of Pb and/or Cd toxicity that can possibly
occur immediately or later in their lives.
The researchers conclude that although the more severe
clinical manifestations of heavy metal intoxication may
only be evident in the later years of the consumers’ lives,
it is better if this problem would be addressed
immediately to prevent it. It is not possible to replace
fully the old water lines. The researchers recommend that
the drinking water must at least be treated accordingly so
as to achieve at least the highest allowable concentration
of Cd and Pb in water to prevent or even eliminate
possible Cd and Pb toxicity among students of this well-
known university. Simple filtration might not be enough.
The researchers look into the possibility that the
maintenance and age of the water dispensers/stations may
have contributed to the levels of heavy metals in the
collected water samples. Hence, the researchers
recommend the installation of effective equipment for
water treatment to monitor and totally eliminate if not
reduce the amounts of heavy metals particularly lead and
cadmium inside the university drinking water stations. It
is also recommended that every college must have a
schedule of cleaning for their water stations and should
regularly replace the filter to ensure its efficiency.
For the future analysts, further studies must be conducted
regarding the sources of water used for the drinking
stations. Quantitative determination of the other heavy
metals may be performed to further stress the problem of
possible heavy metal intoxication acquired from these
water stations. A survey could also be done correlating
the concentrations of the mentioned heavy metals to the
overall health of the constituents of the university.
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Table 2. Tabulation of Lead Concentrations (ppm) Per Trial Per Sample As per Determined by AAS: A=CD, B=CP, C=CN, D=CM, E=CAS
Cafeteria, F=CAS Quadrangle, G=Robinson’s Place Ermita Food Court
G
Table 3. Tabulation of Cadmium Concentrations (ppm) Per Trial Per Sample As per Determined by AAS: A=CD, B=CP, C=CN, D=CM, E=CAS
Cafeteria, F=CAS Quadrangle, G=Robinson’s Place Ermita Food Court