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Collecting and analyzing environmental samples
Collecting and analyzing environmental samples
The assessment team will collect environmental samples. The purpose of the environmental sampling is to identify which areas in the urban environment have fecal contamination and determine the magnitude of that contamination. The focus of the sampling is the public domain that would be affected by sanitation infrastructure changes. If the team has enough staff, this can be done at the same time as the surveys. Another option is to have a laboratory collect and analyze the samples. When planning logistics for sampling, the assessment team needs to consider traffic patterns, typical working days, safety, when the laboratories are open, etc. Sampling can also be used as an opportunity to collect GPS data and photos at the site of each sampling to use in conjunction with the environmental samples to develop a contamination map.
Sites for environmental sampling should be identified based primarily on prior transect walk visits in a neighborhood and information culled from key informant interviews.
Table 1 shows the types of samples to be collected from the selected target neighborhoods based on the pathways selected for this assessment
Figure 1. The exposure assessment team in Vellore, India collects samples from an open drain.
After identification of these sites, a daily sampling plan should be designed to enable the field team to efficiently collect samples for laboratory processing. The sampling plan should be based on the capacity of the laboratory to process samples within the workweek. Typically a laboratory may be able to process samples for only 4 out of a 5 day work week due to laboratory assay processing time. 40 samples per week/10 samples per day is advised for the SaniPath Exposure Assessment Tool. If two technicians are processing laboratory samples the process can be expedited (80-100 samples per week/20-25 samples per day). Table 2 shows an example daily sampling plan.
Standard Operating Procedures for Environmental Sampling
Standard Operating Procedures for Environmental Sampling
Summary
Summary
These protocols provide instruction for sterile collection of drinking water, surface water, ocean water, open drains, flooded areas, produce (vegetables) from markets that are eaten raw, street food from vendors, swabs of latrine surfaces, and soil. Methods are designed to collect samples for microbial analysis to detect possible fecal contamination in these environments.
Sample Collection of Drinking Water (Municipal Water, Other Drinking Water) or Bathing Water
Sample Collection of Drinking Water (Municipal Water, Other Drinking Water) or Bathing Water
The following materials and equipment are needed:
1. Gloves
2. Ice chest with frozen ice packs
3. Sterile 100ml Whirl-Pak bags with sodium thiosulfate for chlorinated water samples
4. Sterile 100ml Whirl-Pak bags for non-chlorinated water samples
5. Cotton swabs
6. 70 % ethanol solution
7. Android device
8. Extra paper forms
9. Pen
10. Permanent Marker
Preparation for collecting piped drinking water or bathing water sample
Preparation for collecting piped drinking water or bathing water sample
The day before fieldwork, make sure all sampling materials are clean, sterile, and of adequate quantity and quality. Generate unique sample identification codes (ID) that would be used for Whirl Pak bags of samples collected. Prepare one label for each unique sample ID using a permanent marker.
Sampling protocol for drinking water
Sampling protocol for drinking water
1. Take a photo of the sampling location using the ONA Sample Picture form.
2. Using a permanent marker, label clean, sterile 100mL Whirl-Pak bag with the Sample ID.
3. Put on gloves and spray your hands with alcohol.
4. Spray the cotton wool with 70% ethanol. First sanitize the interior of the mouth to the water source (this may be a tap, pump, or dispenser), rubbing the cotton wool in a circular motion around the interior about half a finger deep. Fold the cotton wool so that a new surface is available and spray the cotton wool with more alcohol. Wipe the exterior of the drinking water source with the sprayed cotton wool making sure to clean both the tip and outside the tap, pump, or dispenser.
5. Make sure there are tablets of sodium thiosulfate in the 100ml Whirl-Pak bags for all municipal piped drinking water collection samples. Sodium thiosulfate tablets are not needed in the Whirl-Pak bags for non-chlorinated drinking water or bathing water samples.
6. Let the water run for 30 seconds. After the 30 seconds, open the labeled Whirl-Pak bag by pulling gently on the tabs on the side of the bag without touching the mouth or inside of the bag. Do not touch the mouth of tap with the bag or your hands. Fill the Whirl- Pak bag carefully through the central opening to above the 100mL mark. We will need more slightly more than 110 mls per sample (fill the sample to the second line).
7. Close the Whirl-Pak bag by carefully and quickly rotate the bag, without spilling the sampled water, and then twisting the wire tabs together. Make sure that the bag is completely closed and not leaking (turn it upside down to check).
8. Confirm that the ID is in place and carefully place the Whirl-Pak bag into the ice chest with frozen ice packs.
9. Transport samples to the lab within 6 hours of collection and deliver samples to one of the designated laboratory personnel.
10. Immediately transfer the sample(s) into a 4°C refrigerator until they are ready to be analyzed. Samples should be stored no longer than 6 hours before analysis.
Sample Collection of Surface and Ocean Water
Sample Collection of Surface and Ocean Water
The materials and equipment needed for collecting samples of marine, river, and pond water are below.
1. Gloves
2. Ice chest with frozen ice packs
3. Sterile 100mL Whirl-Pak bags
4. 70% ethanol
5. Android Device
6. GPS device (optional)
7. Pen
8. Permanent Marker
9. Extra Paper Forms
10. Wader Boots and pants (optional but recommended)
11. Sterile Bucket/Pail (8-10 liter capacity)
Preparation for collecting surface and ocean water samples
Preparation for collecting surface and ocean water samples
The day before fieldwork, make sure all sampling materials are clean, sterile and of adequate quantity . Generate unique sample identification codes (IDs) for Whirl-Pak bags of samples collected.
Sampling protocol for surface and ocean water
Sampling protocol for surface and ocean water
1. Take a photo of the sampling location using the ONA Sample Picture form.
2. Using a permanent marker, label a clean, sterile 100mL Whirl-Pak bag with the Sample ID. Put on gloves and spray your hands with 70% ethanol.
3. Put on the wader boots and then clean gloves.
4. Use a sterile bucket for collecting the sea/surface water. Spray the bucket with 70% ethanol and wipe with a clean paper towel.
5. Wade out into the sea/surface water until the water surface is at least above the knee.
6. Collect some water in the bucket. Swirl the water around to rinse the bucket and then dump the rinse water out.
7. Gently move about 3 meters to the right, taking care to not stir up sand or sediment. Submerge the sterile bucket until it is just under the water surface, and fill it to the top.
8. Set the bucket on the ground, cover it with a clean lid to protect it from exposure to sunlight and airborne contamination. Then allow the collected water to settle for 5 minutes.
9. Open the labeled Whirl-Pak bag, by pulling gently on the tabs on the side of the bag, without touching the mouth or inside of the bag.
10. Slowly pour the settled water into the 100mL Whirl-Pak bag, being very careful to not agitate the bottom layer of sand. Stop pouring the water when you see sand moving with the water towards the 100 mL Whirl-Pak bag.
11. Fill the Whirl Pak bag carefully to slightly above 110mL(the second line on the bag).
12. Close the Whirl-Pak bag by carefully and quickly rotating the bag, without spilling the sample, and then twisting the wire tabs together. Make sure that the bag is completely closed and not leaking (turn it upside down to check).
13. Dump the remaining water and settled sand out of the bucket.
14. Sterilize the bucket by spraying with 70% ethanol and wiping with a clean paper towel.
15. Be sure to collect samples for each Whirl-Pak bag from a different sample site.
16. Confirm that the printed labels are still firmly in place and place in the samples in the ice chest with frozen ice packs.
17. Transport samples to the lab within 6 hours of collection and deliver samples to one of the designated laboratory personnel.
18. Immediately transfer the sample (s) into a 4°C refrigerator until they are ready to be analyzed. Samples should be stored no longer than 6 hours before analysis
Sample Collection of Open Drain and Flood Water
Sample Collection of Open Drain and Flood Water
The materials and equipment needed to collect samples from open drains are as follows:
1. Gloves
2. Ice chest with frozen ice packs
3. Sterile 100ml Whirl-Pak bags
4. 70% ethanol
5. 90% ethanol
6. Android Device
7. Sterile ladle (soup spoon)/ bucket with rope
8. Pen
9. Permanent Marker
10. Extra Paper Forms
11. Lighter
Preparation for field work
Preparation for field work
The day before fieldwork make sure all sampling materials are clean, sterile and of adequate quantity and quality. Generate unique sample identification codes (IDs) for labeling Whirl-Pak bags of samples collected.
Sampling protocol for open drain or flood water
Sampling protocol for open drain or flood water
1. Take a photo of the sampling location using the ONA Sample Picture form.
2. Using a permanent marker, label clean, sterile 100mL Whirl-Pak bag with the Sample ID.
3. Put on clean gloves, spray them with 70% ethanol.
4. Sterilize the ladle/bucket on a rope by spraying with 70% ethanol and wiping with a clean paper towel.
5. Collect the water sample using the sterile ladle/bucket on a rope. If the source is shallow and the bailer cannot be submerged, turn the hand bailer/bucket horizontally to fill, but take care to not scoop up sediment or trash in the water.
6. Open the labeled Whirl Pak bag by pulling gently on the tabs on the side of the bag without touching the mouth or inside of the bag.
7. Carefully pour the drain water sample from the bailer into the100mL labeled Whirl-Pak bag.
8. Close the Whirl-Pak bag by carefully and quickly rotating the bag, without spilling the sample, and then twisting the wire tabs together. Make sure that the bag is completely closed and not leaking (turn it upside down to check).
9. Confirm that the label is still affixed to the bag. Place the 100mL Whirl-Pak in the cooler with ice packs.
10. Clean the ladle/bucket by spraying it with 90% ethanol and then igniting the ethanol with a lighter. Take care to do this well away from any flammable liquids or dry environments that could catch on fire (like grass). Keep hands well away from the mouth of the ladle/bucket.
11. Transport samples to the lab within 6 hours of collection and deliver samples to one of the designated laboratory personnel.
12. Immediately transfer the sample(s) into a 4°C refrigerator until they are ready to be analyzed. Samples should be stored no longer than 6 hours before analysis.
Sample Collection of Produce (Raw Vegetables)
Sample Collection of Produce (Raw Vegetables)
The materials and equipment needed to collect produce samples are below:
1. Gloves
2. Ice chest with frozen ice packs
3. 70% ethanol
4. Sterile 2 liter Whirl-Pak bags
5. Android device
6. Pen
7. Permanent Marker
8. Extra Paper Forms
9. Money for purchasing produce
Preparation for field work
Preparation for field work
The day before fieldwork, make sure all sampling materials are clean, sterile and of adequate quantity and quality. Generate unique sample identification codes (IDs) for labeling Whirl-Pak bags of samples collected.
Sampling protocol for produce (fruits and vegetables)
Sampling protocol for produce (fruits and vegetables)
1. Take a photo of the sampling location using the ONA Sample Picture form.
2. Using a permanent marker, label clean, sterile 2L Whirl-Pak bag with the Sample ID.
3. Put on gloves and spray your hands with 70% ethanol.
4. Open the labeled Whirl-Pak bag by gently pulling out the tabs of the side of the bag without touching the mouth or inside of the bag.
5. If you are selecting produce at a market vendor’s stall, carefully open the Whirl- Pak bags without touching the mouth of the bag. Ask the vendor to place the produce in the bag. Only collect as much produce as you think one person may consume during a single meal (i.e. one serving). Quickly close bag.
6. Confirm that the label is still affixed to the bag. Place the Whirl-Pak bag in the ice chest with ice packs.
7. Transport samples to the lab within 6 hours of collection and deliver samples to one of the designated laboratory personnel.
8. Immediately transfer the sample(s) into a 4°C refrigerator until they are ready to be analyzed. Samples should be stored no longer than 6 hours before analysis.
Sample Collection of Street Food (Commonly Eaten In Neighborhood)*
Sample Collection of Street Food (Commonly Eaten In Neighborhood)*
*Protocol adapted from the WASH Benefits Study
The materials and equipment needed to collect street food samples are below:
1. Gloves
2. Ice chest with frozen ice packs
3. 70% ethanol
4. Sterile 2 liter Whirl-Pak bags
5. Android device
6. Pen
7. Permanent Marker
8. Extra Paper Forms
9. Money for purchasing street food
Preparation for field work
Preparation for field work
The day before fieldwork, make sure all sampling materials are clean, sterile and of adequate quantity and quality. Generate unique sample identification codes (IDs) for labeling Whirl-Pak bags of samples collected.
Sampling protocol for street food
Sampling protocol for street food
1. Using a permanent marker, label clean, sterile 2L Whirl-Pak bag with the Sample ID.
2. Put on gloves and spray your hands with 70% ethanol.
3. Open the labeled Whirl-Pak bag by gently pulling out the tabs of the side of the bag without touching the mouth or inside of the bag.
4. If you are selecting street food at a market vendor’s stall, carefully open the Whirl- Pak bags without touching the mouth of the bag. Ask the vendor to place the food in the bag. Only collect as much food as you think one person may consume during a single meal (i.e. one serving). Quickly close bag.
5. Confirm that the label is still affixed to the bag. Place the Whirl-Pak bag in the ice chest with ice packs.
6. Transport samples to the lab within 6 hours of collection and deliver samples to one of the designated laboratory personnel.
7. Immediately transfer the sample(s) into a 4°C refrigerator until they are ready to be analyzed. Samples should be stored no longer than 6 hours before analysis.
Sample Collection of Soil and Sand
Sample Collection of Soil and Sand
Materials and equipment needed for collecting soil and sand samples:
1. Gloves
2. 70% ethanol
3. 90% ethanol
4. Sterile spatula
5. Sterile 100 mL Whirl-Pak bags
6. Ice chest with frozen ice packs
7. Mobile Device
8. Pen
9. Permanent marker
10. Extra Paper Forms
Preparation for field work
Preparation for field work
The day before fieldwork make sure all sampling materials are clean, sterile and of adequate quantity and quality. Generate unique sample identification codes (IDs) for labeling Whirl-Pak bags of samples collected.
Sampling protocol for collecting soil and sand samples
Sampling protocol for collecting soil and sand samples
1. Take a photo of the sampling location using the ONA Sample Picture form.
2. Select the site you will collect samples from. Take precautions to avoid contamination of the samples by not walking through the area.
3. Using a permanent marker, label clean, sterile 100mL Whirl-Pak bag with the Sample ID.
4. Put on clean gloves and spray them with 70% ethanol.
5. Sterilize the spatula by spraying with 90% ethanol and wiping with a clean paper towel.
6. Grasp the end of a sterile spatula, taking care to not touch the tip. Insert the spatula into the soil/sand/sediment at a 45° angle to a depth of 5cm (about half the length of the spatula). If the sample is hard-packed, use the scoop to gently break up the sample at the area before inserting. If the area is so hard packed that the soil/sand/cannot be dislodged, stop attempts to collect a sample at that spot and attempt to find another spot within the sample area.
7. Gradually lift the spatula until it is parallel with the ground. Insert the spatula halfway into the bag and carefully empty the contents into the 100mL Whirl-Pak bag. If some of the sample sticks to the scoop, place your fingers on the outside of the bag and gently press them against the top of the scoop and press downwards until the sample is removed into the bag.
8. Repeat steps 4 to 5, collecting a composite of up to 7 samples. Attempt to collect samples from a variety of locations, including wet soil and dry soil.
9. For areas near rivers and ponds, drains, toilets, or any other similar area, a composite should be collected from an area of approximately 3 meters squared.
10. For markets or play areas, collect 5 composite samples from a central location, and at each of the boundary corners into the market as indicated in the diagram below
11. Close the Whirl-Pak bags. Confirm that the labels are still firmly in place and place the 100 mL sample bag in the cooler with the ice packs.
12. Sterilize the spatula again by spraying with 90% ethanol and wiping with a clean paper towel.
13. Transport samples to the lab within 6 hours of collection and deliver samples to one of the designated laboratory personnel.
14. Immediately transfer the sample(s) into a 4°C refrigerator until they are ready to be analyzed. Samples should be stored no longer than 6 hours before analysis.
Soil/Sand Sample Collection: Market Collection Map
Sample Collection of Swabs from Latrine Surfaces
Sample Collection of Swabs from Latrine Surfaces
Materials and equipment needed for collecting swab samples:
1. Gloves
2. Ice chest with frozen ice packs
3. EnviroMax plus Sterile Environmental Sampling Swabs (#25-88050), or comparable swab
4. 70% ethanol
5. T-square or a scale with marks at 2.5cm, 5cm, 10cm, and 20cm on each arm
6. Mobile device
7. Pen
8. Permanent Marker
9. Extra paper forms
10. Blank adhesive labels
11. Kitchen paper towel
Preparation for field work
Preparation for field work
The day before fieldwork, make sure all sampling materials are clean, sterile and of adequate quantity and quality. Generate unique sample identification (ID) codes that will be used for labeling swabs collected.
Sampling protocol for swab samples
Sampling protocol for swab samples
1. Take a photo of the sampling location using the ONA Sample Picture form.
2. Affix a Sample ID label from the strip of labels to an EnviroMax swab tube.
3. Put gloves on clean gloves and spray them with 70% ethanol and then air dry.
4. Sterilize the T- square by spraying it with 70% ethanol and wiping it down with a clean paper towel.
5. Grasp the orange cap of the EnviroMax swab and twist off the lid. DO NOT touch the stem or swab surface or the open mouth of the tube to your gloves or any other object.
a. If the item/surface to be swabbed is flat, hold the T- square against the surface and swab an area of at least 100 cm2 (10cmx10cm) on each arm of the T- square.
b. If you are right-handed, start at the bottom right corner of the object and press one side of the swab firmly to the surface. Hold the swab at a slight angle to the object so that the swab surface is in maximal contact with the object but your gloves do not rub against the object (~30° angle). Move the swab from right to left in horizontal lines, overlapping the upper row over the bottom row. At the midway point, turn the swab over and use the opposite side to finish swabbing the upper half of the object. If you are left-handed, swab from left to right starting at the bottom left corner and overlapping rows from bottom to top.
c. If the item/surface to be swabbed is small (size of an orange) and round or irregular, then carefully hold the object between two fingertips and swab the entire surface of the object, starting at the point closest to you and swab away from you so that the palm of your hand moves over an area that has already been swabbed. After half of the object has been swabbed, turn the swab over and swab the remaining area with the opposite side.
d. If the item/surface to be swabbed is round or irregular, and is larger than a grapefruit or softball but equal to or smaller than a soccer ball, then swab half of the surface area, starting at the point closest to you and work the swab away from you so that the palm of your hand moves over an area that has already been swabbed. After half of the object has been swabbed, turn the swab over and swab the remaining area with the opposite side.
e. If the item/surface to be swabbed is not flat, but is larger than a soccer ball, use the T-square to estimate an area of approximately 10 cm by 10 cm and swab the area as instructed in instructions 9a.
6. For public latrines swab a composite of door handles and walls of the latrine (i.e. use the same swab for both the door handle and latrine walls).
7. Carefully insert the swab back into the tube and screw the cap on tightly. Confirm that the label is still affixed to the tube.
8. Place the swab into the cooler immediately after collection.
9. Transport samples to the lab within 6 hours of collection and deliver samples to one of the designated laboratory personnel.
10. Immediately transfer the sample(s) into a 4°C refrigerator until they are ready to be analyzed. Samples should be stored no longer than 6 hours before analysis
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