Since a variety of tests are now available for fecal contamination, the question becomes, “How do you choose between the tests?

If your concern is contamination from surface water, river water, or storm water after a flood, total Bacteroides is the best choice since runoff from streets (dog manure), manure contaminated runoff from agricultural operations, and combined (both sanitary and storm water) treatment plant overflows are a concern. In this situation, you have the potential for human disease caused from both animal and human sources of contamination. Total Bacteroides will indicate the presence of all of these potential contaminants.  

The human Bacteroides test is the best choice if your concern is a backed-up toilet or a back-up/overflow from a sanitary sewer (which handles human discharges only).  Using human Bacteroides virtually eliminates any background contamination from pets.

 Bacteroides may be used for indoor environmental surface or bulk sampling, non-permitted, investigational, or research-driven water, wastewater and soil samples, since there are no stipulated permits or statutory requirements.

However, if you are sampling drinking water, recreational water, or wastewater effluent as part of a compliance evaluation for a regulated National Prevention and Discharge Elimination System (NPDES) permit condition, you are still required to use culture dependent FIB methods for coliforms, E. coli, or Enterococci.

To date, research has been done using HPyVs PCR tests to determine human fecal contamination in water and wastewater only. Since their use has not been validated for surface, bulk, soil or sediment samples, sampling for these should be restricted to surface water and wastewater samples only.  The benefit of using HpyVs in this instance is the complete elimination of background contamination by animal fecal material.

Sampling Procedure for Swab Samples

1. Obtain a sterile 1 mL Butterfield’s Solution swab (EMSL Product ID 8708935) to collect and transport samples (provided at your request by EMSL).

2. With gloves on, remove swab from sterile packaging.

3. Carefully unscrew cap of sampling device – swab is attached to the lid of the cap.

4. Gently press out excess solution from sampling swab by pressing the swab against the inside wall of the tube with a rolling motion.

5. Hold swab at an approximate 30° angle from the sampling surface, taking care not to contaminate any part of the swab or the sampling site.

6. Using firm, even pressure move the swab slowly and thoroughly over an entire

4" x 4" sampling area, rewetting the swab tip with the Neutralizing Solution as needed. First horizontally, then vertically:

7. After sampling is complete, carefully put swab back into vial and close cap tight.

8. Label the sample using a permanent ink marker.

9. Background samples in non-fecally contaminated areas should be taken.

Sampling Procedure for Bulk or Soil Sampling

1. Obtain sterile sampling bags (Ziplock-type) or 125 ml sterile bottles to collect and transport samples (provided at your request by EMSL).

2. Wearing sterile gloves and using sterile, clean tools remove a representative area along with the building material (sheetrock, wood, etc). 1 inch square is sufficient.

3.Tools used for sampling must be sterilized with 70% isoprpopyl alcohol and air dried between sample collections.

4. For soil sample, fill a 125 ml sterile bottle halfway with soil. 

5. Label the outside of the bag with the sampling location or description.

Sampling Procedure for Air Samples

1. Obtain a 3-piece PCR air/dust-sampling cassette from EMSL.

2. Remove the upper (blue) and lower (red) plugs of the cassette.

3. Attach a vacuum pump to the cassette through the lower opening.

4. Sample as much air as desired through the upper opening. There is no upper limit to sampling time but take a 4 hour sample at least

5. An air sample in an uncontaminated area should be taken as a background sample

6. Record the VOLUME of air sampled and ship cassette to EMSL. No refrigeration is needed.

Sampling Procedure for Dust Samples

1. Obtain a 3-piece PCR air/dust-sampling cassette from EMSL.

2. Remove the upper (blue) and lower (red) plugs of the cassette.

3. Attach a small piece of tubing to the upper opening. Cut a 45-degree angle at the end of the tubing.

4. Attach a vacuum pump to the cassette through the lower opening.

5. Begin collecting dust through the upper tubing. There is no upper limit to sampling time.

6. A dust sample in an uncontaminated area should be taken as a background sample.

7. Ship the cassette to EMSL. No refrigeration is needed.

Sampling Procedure for Water/Liquid Samples

1. All water samples should be taken in sterile sampling containers, which our

laboratory can provide upon request.

2. Fill container with 1000 mL of water/liquid, or as much water as possible and seal

securely to prevent leakage during transport.

3. Transport sample using gel ice packs to EMSL