This document discusses the preservation of water samples for environmental engineering. It defines preservation as maintaining the original properties of water samples and explains that preservation is necessary to prevent changes in analyte concentrations between sample collection and laboratory analysis. It then describes common preservation methods like chemical addition, pH control, refrigeration, and freezing. Specific details are provided on preservation containers, techniques for various chemical and microbiological parameters, and required sampling volumes and holding times. The document serves to guide students on proper sample collection, preservation, and handling for environmental analysis.

1. Sarvajanik College of
Engineering andTechnology
Topic :- Preservation of Samples
Subject :- Environmental Engineering (2150603)
Branch :- Civil Engineering (06)
Semester :- 5th
Guided by :- Prof. Mitali Shah
Prof. Chaitali Patel

2. Submitted By
Name Enrollment No.
Prajapati Jay 160420106053
Rangoonwala Abhay 160420106054
Ravani Harsh 160420106055
Ravani Prit 160420106056
Savaliya Smit 160420106057
Shah Jainam 160420106058
Shah Siddh 160420106059

3. ANNEXTURE
 Meaning and Need of Preservation
 Preservation containers
 Preservation Methods

4. Meaning and Need of Preservation
 Preservation is the process to maintain original properties of water samples.
 Sample preservation is the measure or measures taken to prevent reduction or
loss of target analytes.
 Analyte loss can occur between sample collection and laboratory analysis because
of physical, chemical, and biological processes that result in chemical
precipitation, adsorption, oxidation, reduction, ion exchange, degassing, or
degradation.
 Preservation stabilizes analyte concentrations for a limited period of time. Some
samples have a very short holding time.

5. Preservation Container
 Containers are of mainly two types:-
1. Plastic Container:-
Bottles and lid linings are made of the
following plastics: high- or low-density
polyethylene, polypropylene, polystyrene,
polyvinyl chloride orTeflon
1. GlassContainer

6. Preservation Methods
 Preservation methods for chemical parameters (on-site analysis):-
 Preservation methods for microbiological and chemical parameters (laboratory
analysis)

7. Method of Preservation
• Chemical Addition
• pH control
• Refrigeration
• freezing

8. ChemicalAddition
• The most convenient preservative is a chemical which can be added to a sample
bottle prior to sampling.
• When the sample is added, ·the preservative disperses immediately, stabilizing
the parameter(s) of concern for long periods of time
• When the preservative added interferes with other parameters being measured,
additional samples for those parameters must be collected.
• For example, concentrated nitric acid added for the preservation of some of the
metals would interfere with BOD, so an additional sample must be collected for
BOD.

9. Ph Control
• pH control to preserve the sample is dependent upon chemical addition.
• For example:-
to keep metal ions in a dissolved state concentrated nitric acid is
added to lower the pH to less than 2.

10. Freezing
• Freezing has been the subject of many preservation studies.
• It is felt by some that freezing would be a method for increasing the holding
time and allowing collection of a single sample for all analysis
• The residue solids components (filterable and nonfilterable) of the sample
change with freezing and thawing.
• Return to equilibrium and then high speed homogenization is necessary
before any analysis can be run
• This method may be acceptable for certain analysis but not as a general
preservation method.

11. Refrigeration
• Refrigeration or 1c1ng has also been studied with various results.
• This is a common method used in field work and has no detrimental effect on
sample composition.
• Although it does not maintain integrity for all parameters, it does not interfere
with any analytical methods.

13. Preservation methods for chemical
parameters (on-site analysis)
Parameter Preservative* Container*
Recommended
volume (ml)
Time between
sample collection
and analysis
Alkalinity N P or G 10 30 minutes
Hardness N P or G 10 30 minutes
Total residual bromine N P or G 10 30 minutes
Chloramines N P or G 10 30 minutes
Free residual chlorine N P or G 10 30 minutes
Total residual chlorine N P or G 10 30 minutes
pH N P or G 10 2 Hours
WaterTemperature N P or G 125 3 minutes

14. Preservation methods for microbiological and
chemical parameters (laboratory analysis)
Parameter Preservative* Container*
Recommended
volume (ml)
Time between
sample collection
and analysis
MICROBIOLOGY
Escherichia coli ST3 PPS or GS 100 48 hours
Pseudomonas
aeruginosa
ST3 PPS or GS 100 48 hours
Staphylococcus
aureus
ST3 PPS or GS 100 48 hours
Fecal coliforms ST3 PPS or GS 100 48 hours
CHEMISTRY
Turbidity N/A P or G 125 48 hours

15. Sampling and Handling Requirement