5 Monivong Boulevard, P.O Box. 983, Phnom Penh, Cambodia accueil@pasteur-kh.org

Recommendations

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Conditions of Sampling, Packaging & Transportation

of Water Samples For Microbiological Analysis

 

These recommendations are in accordance of the following international standards:

- NF EN ISO 5667-3: Preservation and handling of water samples

- NF EN ISO 19458: Sampling for water analysis

- FD T90-520: Guide technique de prélèvement pour le suivi sanitaire des eaux en application du code de le Santé Publique (réglementation française)

1. General recommendations

  • The customer must make an appointment with the laboratory specifying the type of water analysis and microbiological parameters requested.

  • Written guidelines/procedures/methodology in Khmer and in English to collect the samples and recommendations for their storage/transportation are available in the LMMAE and could be requested by the customers at the bottles collection.

Sterile vials for single use polyethylene are available for samples with a capacity ranging from 500 ml, 1000 ml to 2000 ml. – these bottles are added or not of sodium thiosulfate to a final concentration of 20 mg /l.

  • Container labels should withstand wetting, drying and freezing without detaching or becoming illegible. The labelling system shall be waterproof to allow use on site.

  • The exact information given in the sampling report and on the sample labels depends on the objectives of the particular measurement programme. In all cases, an indelible label shall be secured to the sample container. For each sample, at least the following information shall be available.

— date, time and location of sampling

— sample number

— description of sample

— name of sampling personnel

— details of sample preservation, or fixation used;

— details of sample storage used

— any information regarding integrity and manipulation of the sample;

— any other information, as necessary

__ a unique identifier, traceable to sample date, location, and sample number shall appear on the label of the sample container

__ all other information is supplementary and should be detailed in the sample report

2. Conditions of transport and storage

  • Keep the time between sampling and analysis in the laboratory as short as possible. For drinking waters,

  • Analysis should ideally be started within the same working day.

  • Cool samples — ideally (3-5) °C — during transport (e.g. by using ice packs or melting ice), unless otherwise stated in specific standards. Take care not to freeze them (except for viruses). Protect samples from Sunlight.

  • For samples transported for periods over 8 h, it is necessary to monitor and record the temperature.

For samples transported for periods over 8 h, it is necessary to monitor and record the temperature.

Transport conditions shall be documented. Nevertheless be careful:

 not to put ice-packs in direct contact with the sample, as this can result in freezing it.

 to adjust the number, volume and position of ice packs according to samples number, mass and initial temperature.

Document the procedure required for longer transport times (8 h).

  • Warm and cold samples shall be transported separately.

3. Delivery time of samples to the laboratory

  • The following table provides a chart of recommendations for the maximum period of delivery. The times listed are estimates: they depend on the type of water, the physiological state of microorganisms (eg disinfection or not) or even the method of analysis.

  • In case of delay exceeding the recommended time of delivery, the results must be interpreted carefully and subject to control by another analysis.


 
 

Recommended (R) & acceptable (A) values 

for maximum sample storage times including transport time 

& temperatures unless otherwise specified in specific standards

 

 

 

Maximum sample storage time (h) including transport

 

Storage water temperature (°C)

 

Observation

R

A

R

A

 

 

General

Culturable microorganisms (22, 30 or 36 °C)

 

 

8

 

12

 

5+3 °C

 

 

Faecal indicators, vegetative bacteria

- E. coli (and coliform bacteria)

- Enterococci

- Clostridium perfringens (vegetative cells)

 

 

 

12

 

 

 

18

 

 

 

5+3°C

 

 

Spores

-Spores of sulfite-reducing bacteria

(Clostridium spp.)

 

24

 

72

 

5+3°C 

 

Die-off observed in raw waters after 24 h

Viruses

Bacteriophages

 

48

 

72

 

5+3°C

 

 

Faecal pathogens

Salmonella spp. and other Enterobacteriaceae

 

Cryptosporidium oocysts

 

Giardia cysts

 

 

12

 

24

 

24

 

 

18

 

96

 

96

 

 

5+3°C 

 

5+3°C 

 

5+3°C 

 

 

 

 

Ambient

 

 

 

Other microorganisms

Amoebae

 

Pseudomonas aeruginosa

 

 

Legionella spp.

 

 

 

Helminth eggs

 

24

 

8

 

 

24

 

 

 

48

 

96

 

12

 

 

 

 

48

 

72

 

1 week

 

5+3°C 

 

Ambient

 

 

5+3°C 

 

5+3°C

 

5+3°C 

 

5+3°C 

 

 

 

 

5-3°C

 

 

Ambient

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sample stabilized at pH = 2