Sodium thiosulfate (Na 2 S2O3) is a satisfactory dechlorinating agent that

neutralizes any residual halogen and prevents continuation of

bactericidal action during sample transit.

Hi Dr

BACTERIAL SAMPLING*

BioVir Laboratories, Inc.

685 Stone Road, Unit 6, Benicia, CA 94510

1-800-442-7342 (Fax ) 707-747-1751

E-Mail: Craig Johnson @ [email protected]

Web Site: www.biovir.com

Sampling Containers

Collect samples for microbiological examination in bottles

that have been cleansed and rinsed carefully, given a final rinse

with distilled water, and sterilized. (Please refer to Standard

Methods for the Examination of Water and Wastewater, 18th

edition) for wash and sterilization protocols. Alternatively,

purchase pre-sterilized containers and integrity check each

sealed vessel prior to use.

Sample Dechlorination

Add a reducing agent to containers intended for the

collection of water having residual chlorine or other halogen

unless they contain broth for direct plating of sample. Sodium

thiosulfate (Na2

S2

O3

) is a satisfactory dechlorinating agent that

neutralizes any residual halogen and prevents continuation of

bactericidal action during sample transit. Alternately, purchase

pre-sterilized containers appropriate for the

volume of sample desired which contain Sodium

thiosulfate in pellet form. The examination then

will indicate more accurately the true microbial

content of the water at the time of sampling.

For drinking water samples, the concentration

of dechlorinating agent: 0.1 mL of a 3%

solution of Sodium thiosulfate in a 120-mL bottle

will give a final concentration of 18 mg/L in the

sample and will neutralize up to 5 mg/L residual

chlorine. In emergency disinfection with higher

concentrations of chlorine add sufficient dechlorination

agent to give a concentration of 100 mg/L in

the sample.

Sample Collection - General

1. When the sample is collected, leave ample air space in

the bottle (at least 2.5 cm) to facilitate mixing by shaking, before

examination.

2. Collect samples that are representative of the water

being tested, flush or disinfect sample ports, and use aseptic

techniques to avoid sample contamination.

3. Keep sampling bottle closed until it is to be filled.

4. Remove stopper and cap as a unit. DO NOT contaminate

inner surface of stopper or cap and neck of bottle.

5. Fill container without rinsing.

6. Replace stopper or cap immediately, and if used,

secure hood around neck of bottle. Alternately, secure ìtamper

proofî devices applicable to sample container.

Sample Collection - Potable Water

If the water sample is to be taken from a distribution

system tap without attachments, select a tap that is supplying

water from a service pipe directly connected with the main, and

is not, for example, served from a cistern or storage tank. Open

tap fully and let water run to waste for 2-3 minutes, or for a time

sufficient to permit clearing the service line. Reduce water flow

to permit filling bottle without splashing. If tap cleanliness is

questionable, apply solution of sodium hypochlorite (100 mg

NaOCl/L) to faucet before sampling; let water run for additional

2 to 3 minutes after treatment. Do not sample from leaking taps

that allow water to flow over the outside of the tap. In sampling

from a mixing faucet remove faucet attachments such as screen

or splash guard, run hot water for 2 minutes, then cold water for

2 to 3 minutes, and collect sample as indicated above.

If the sample is to be taken from a well fitted with a hand

pump, pump water to waste for about 5 minutes

before collecting sample. If the well is

equipped with a mechanical pump, collect

sample from a tap on the discharge. If there is

no pumping machinery, collect a sample

directly from the well by means of a sterilized

bottle fitted with a weight at the base; take care

to avoid contaminating samples by any surface

scum.

In drinking water evaluation, collect

samples of finished water and from distribution

sites selected to assure systematic coverage

during each month. Carefully choose distribution

system sample locations to include dead-end sections to

demonstrate bacteriological quality throughout the network and

to ensure that localized contamination does not occur through

cross-connections, breaks in the distribution lines, or reduction

in positive pressure. Sample locations may be public sites

(police and fire stations, government office buildings, schools,

bus and train stations, airports, community parks, commercial

establishments (restaurants, gas stations, office buildings,

industrial plants), and buildings, and townhouse complexes,

and special sampling stations built into the distribution network.

Establish sampling program in consultation with state and local

health authorities.

Sample Collection - Raw Water Supply

In collecting samples directly from a river, stream, lake,

reservoir, spring, or shallow well, obtain samples representative

of the water that is the source of supply to consumers. It is

undesirable to take samples too near the bank or too far from

the point of drawoff, or at a depth above or below the point of

drawoff.

BACTERIAL SAMPLING

BioVir Laboratories, Inc.

685 Stone Road, Unit 6, Benicia, CA 94510

1-800-442-7342 (Fax ) 707-747-1751

E-Mail: Craig Johnson @ [email protected]

Web Site: www.biovir.com

Sample Collection - Surface Waters

Stream studies may be short-term, high-intensity efforts.

Select bacteriological sampling locations to include a baseline

location upstream from the study area, industrial and municipal

waste outfalls into the main stream study area, tributaries except

those with a flow less than 10% of the main stream, intake

points for municipal or industrial water facilities, downstream

samples based on stream flow time, and downstream recreational

areas. Dispersion of wastewaters into the receiving

stream may necessitate preliminary cross-section studies to

determine completeness of mixing. Where a tributary stream is

involved, select the sampling point near the confluence with the

main stream. Samples may be collected from a boat or from

bridges near critical study points. Choose sampling frequency

to be reflective of stream or water body conditions. For example,

to evaluate waste discharges, sample every 4 to 6 hours and

advance the time over a 7 to 10 day period.

To monitor stream and lake water quality establish

sampling locations at critical sites. Sampling frequency may be

seasonal for recreational waters, daily for water supply intakes,

hourly where waste treatment control is erratic and effluents are

discharged into shellfish harvesting areas, or even continuous.

Sampling Collection - Bathing Beaches

Sampling locations for recreational areas should reflect

water quality within the entire recreational zone. Include sites

from upstream peripheral areas and locations adjacent to

drains or natural contours that would discharge stormwater

collections or septic wastes. Collect samples in the swimming

area from a uniform depth of approximately 1 meter. Consider

sediment sampling of the water-beach (soil) interface because

of exposure of young children at the waterís edge.

To obtain baseline data on marine and estuarine bathing

water quality, include sampling at low, high, and ebb tides.

Sample Collection - Sediments and Sludges

The bacteriology of bottom sediments is important in water

supply reservoirs, in lakes, rivers, and coastal waters used for

recreational purposes, and in shellfish-growing waters. Sediments

may provide a stable index of the general quality of the

overlying water, particularly where there is great variability in its

bacteriological quality.

Sampling frequency in reservoirs and lakes may be

related more to seasonal changes in water temperatures and

storm water runoff. Bottom sediment changes in river and

estuarine waters may be more erratic, being influenced by

stormwater runoff. increased flow velocities, and sudden

changes in the quality of effluent discharges.

Bacteriological examination of sludges from water and

wastewater treatment processes is desirable to determine the

impact of their disposal into receiving waters, ocean dumping, or

burial in landfill operations. Sludge monitoring also may

indicate the effectiveness of wastewater treatment processes.

Sample Collection - Manual Sampling

Take samples from a river, stream, lake, or reservoir by

holding the bottle near its base in the hand and plunging it, neck

downward, below the surface. Turn bottle until neck points

slightly upward and mouth is directed toward the current. If there

is no current, as in the case of a reservoir, created a current

artificially by pushing bottle forward horizontally in the direction

away from the hand. When sampling from a boat, obtain

samples from upstream side of boat. If it is not possible to

collect samples from these situations in this way, attach a

weight to base of bottle and lower it into the water. In any case,

take care to avoid contact with bank or stream bed; otherwise,

water fouling may occur.

Size of Sample

The volume of sample should be sufficient to carry out all

tests required, preferably not less than 100 mL.

Sample Identification

Accompany samples by complete and accurate identifying

and descriptive data. Do not accept for examination inadequately

identified samples.

Sample Preservation and Storage and Shipment

1. Samples must be stored and shipped cold via sameday

or overnight delivery.

2. HOLDING TIME: All bacterial samples must be placed

on-test within 24 hours of sampling

*Adapted from Standard Methods for the Examination of

Water and Wastewater, 18th Edition.

Additional Information

For more information concerning Cryptosporidium spiking

studies, sampling, detection, immunofluorescent assay and

current regulation, please call BioVir Laboratories at 1-800-

GIARDIA (442-7342).

I agree with  Dr haifa

Hallo Dear

this article may be help you

Sampling Procedures for Drinking Waters

https://www.dews.qld.gov.au/__data/assets/pdf_file/0007/45592/sampling-procedures.pdf

Thanks for all 

https://www.epa.gov/sites/production/files/.../drinking_water_sample_collection.pdf 

used sample for biological or microbial analysis added 0.1 ml to bottle and can To get rid of remove Chlorine, amine chloride, Ozon

Sodium thiosulfate is a satisfactory dechlorination agent that neutralizes any residual halogen and prevents bactericidal action from continuing during transit.

To make a final concentration of Na2S2O3:

• For a 120 ml bottle, 0.1 ml of a 10%solution of Na2S2O3 will neutralise a sample containing up to 15 mg/l residual chlorine.

Dechlorination agent can be less concentrated in drinking water samples:

• In a 120 ml bottle, 0.1 ml of a 3% solution of Na2S2O3 will neutralise a sample containing up to 5 mg/l residual chlorine.

The dechlorination agent's efficacy can be checked by the use of a sodium hypochlorite (NaOCl) quality control (QC) control at 5 or 15 mg/L (or equivalent).

Ref: Standard Methods for the Examination of Water and Wastewater, 23rd edition.

Thank you.