It is a brief account of how to sample and monitor secondary water contaminants in drinking water. Please note that no specific case study is highlighted here. It is a general and analytical approach to the topic under study.

1. Sarah Arshad
Environmental monitoring
Lahore college for women university

2. Problem: Presence of secondary drinking
water contaminants in drinking water
samples collected from different sites of
Lahore

3. Sites selected:
Lahore population density
map (Data Gung Bakhash
town)
Satellite view of Sundar
industrial estate

4. Sites selected
Mehmood Booti
(Waste dumping
site)

5. Personal protection and
preparatory measures
 The sampling team should follow good safety
practices; including do not eat, drink or smoke at the
site, avoid contact with the sample or water flow etc.
 Conduct response at sites using proper hazards signs
and properly trained personnel and equipment.
 Some of the protective personal equipments required
are coveralls, outer and inner chemical - protective
suit, gloves, boots and hard hats. In case of confined
space sampling, remove non- essential personnel from
the site and handle sample with care.

6. Personal protection and
preparatory measures

7. Sampling – For field analysis
 pH: For sampling, fill the plastic container with targeted water sample and keep it cool at
4o C. The volume of water should be at least 100 ml. The pH I.e. Acid Base (H+)
concentration can be measured by Hydrogen ion electrode. See figure 1
 Smell: A certain smell indicates the presence of a specific chemical. The smell helps
identify different types of chemicals that can alter the characteristics of normal drinking
water
 Chloride: : The sample should be collected in glass test tubes with no preservatives
added as the analysis would be immediately carried out on site. In general, the analyst
will need to measure out a known volume of sample using a test tube or flask provided
with the kit and will need to add the DPD reagents, wait a specific reaction time, and
then measure the pink color that develops in the sample. The intensity of the pink color
that develops after the addition of a reagent is measured using a spectrophotometer or a
color comparator and and relates directly to the amount of disinfection residual present
in the sample. See figure 2
Hydrogen ion
electrode
Chloride testing
kit

8. Sampling – Laboratory analysis
 The presence of trace metals like Zinc, Manganese, Silver
etc. can be detected in laboratory. For this purpose, the
sampling is done in plastic or glass bottles but plastic is
preferred. The preservative used is Nitric Acid (HNO3) to
increase the holding time upto 6 months.
 For fluoride, the sample is collected in a plastic bottle and
kept at dark place at room temperature for analysis in
laboratory. The remaining contaminants are also taken in
glass or plastic bottles with suitable added preservative to
enhance its shelf life time

9. Sampling supplies

10. Sample collection documentation

11. Analysis
 Aluminium: One method is when aluminium is reacted with
pyrocatechol violet followed by spectrometric measurement of the
resulting coloured complex. The method is restricted to the
determination of the aquated cations and other forms of aluminium
readily converted to that cationic form by acidification. The limit of
detection is 2 µg/liter. The limit of detection for the determination of
aluminium by inductively coupled plasma atomic emission
spectroscopy ranges from 40 to 100 µg/liter.
 Flame and graphite furnace atomic absorption spectrometric (AAS)
methods are applicable for the determination of aluminium in water at
concentrations of 5–100 mg/liter and 0.01–0.1 mg/liter, respectively. The
working range of the graphite furnace AAS method can be shifted to
higher concentrations either by dilution of the sample or by using a
smaller sample volume

12. Analysis
 Flouride: Fluoride is usually determined by means of an
ion-selective electrode, which makes it possible to
measure the total amount of free and complex-bound
fluoride dissolved in water. The method can be used for
water containing at least 20 µg/liter.
 The colorimeter method of detecting fluoride in water is
by mixing 4 ml diluted water sample along with barium
chloride and 1 ml zirconium xylenol orange reagent. The
color changes from pink to yellow depends on the fluoride
concentration in the sample. By comparing the color
produced with the color chart, the fluoride content in the
water can be quantified. Its detection limit is 2,000 µg/L.

13. Analysis
 Foaming agent: Testing for methylene blue activated
substances (MBAS), isopropanol (IPA) and acetone is
recommended for determining the chemical nature of
foaming agent.
 The procedure for MBAS test is acidify the water sample
by using boric acid or similar substances. Then chloroform
is added with methylene blue solution, a type of cationic
dye. The biphasic mixture that is produced is agitated in
order to disperse the reagents through the organic and
aqueous phases. In this way, concentrations of different
chemical substances can be found by this method.

14. Analysis
 Iron: For the determination of iron in the samples that
were provided, Iron Cell Test Kit is used. In the Test Kit, all
the iron ions present in the samples was reduced to Fe2+
ions by ascorbic acid. In the presence of the medium
thioglycolate, a purple complex was formed because of
Fe2+ reaction with a trizine derivative. The complex was
determined photometrically by using UV-Vis
spectrophotometer. The instrument is designed so that the
sample is placed between a light source and detector.
Depending on the sample, light may be absorbed causing
electrons to be promoted from one energy level to another.
Since different metal ions, have different absorption
patterns, UV-VIS spectroscopy can be used to identify
metal ions in solutions.

15. Analysis
 Mangenese: The presence of manganese in water can be analyzed by using an express
test kit as it gives simple and precise measurements. The procedure to use this kit is given
as: Fill two test tubes with 5 ml of the test water using measurements on the syringe. In
one of the tubes, add 4 drops of indicators in alphabetical order: A, B and C, mixing
thoroughly after every addition. During mixing close the tube with the lid. Let the sample
stand for 3 minutes.
After this, compare the color change of the test tubes with the given color charts.
 Silver: Silver is detected by spectrographic and colorimetric methods. The detection limit
of the spectrographic and colorimetric method with dithizone is 10 µg of silver per liter for
a 20-ml sample. The detection limit of atomic absorption spectroscopy (graphite furnace)
is 2 µg of silver per liter, and of neutron activation analysis (NAA), 2 ng of silver per liter.
This NAA method uses measurement of gamma rays emitted from a sample that was
irradiated by neutrons. The rate at which the gamma rays are emitted is directly
proportional to the concentration of metal present.

16. Analysis
 Zinc: Atomic absorption spectrophotometry is the most widely used
method for the determination of zinc. The detection limit of the direct
air–acetylene flame method is 50 µg/litre. Low concentrations can be
measured by chelating zinc with ammonium pyrrolidine
dithiocarbamate and extracting it with methyl isobutyl ketone
(detection limit 0.5–1 µg/litre).
 Total Dissolved solids: The two principal methods of measuring total
dissolved solids are gravimetric analysis and conductivity. Gravimetric
methods are the most accurate and involve evaporating the liquid
solvent and measuring the mass of residues left.
Procedure for gravimetric method is given as: Weigh the beaker, put a
sample of water in the beaker, and weigh the beaker, heat the beaker to
evaporate the water and weigh the beaker again.

17. EPA standards

18. References
 https://www.vee-ekspert.com/products/express-
tests/manganese-content-test
 https://www.epa.gov/sites/default/files/2015-
11/documents/drinking_water_sample_collection.pdf
 https://www.atsdr.cdc.gov/toxprofiles/tp11-c7.pdf
 https://opus.govst.edu/cgi/viewcontent.cgi?article=1351&context
=capstones#:~:text=An%20easy%2C%20efficient%20and%20saf
e,II)%20ions%20by%20ascorbic%20acid.
 https://www.knowyourh2o.com/indoor-6/foaming-agents
 https://www.who.int/water_sanitation_health/dwq/chemicals/f
luoride.pdf
 https://www.epa.gov/sdwa/secondary-drinking-water-
standards-guidance-nuisance-chemicals

19. THANK YOU