eDNA Soil Kit Instructions

This protocol is designed for soil sample collection using an EnviroDNA eDNA kit. To get the best results, familiarise yourself with our instructions before your sampling survey. More information on tips for avoiding contamination and other sampling considerations are found here. When sampling is complete, return your samples to our laboratory for analysis.

Important information on soil samples

eDNA on terrestrial surfaces can occur in very small quantities, and does not mix in the environment in the same way as aquatic environments. It is critical that collected soil from your sampling location is very thoroughly mixed using the provided sampling bag before sub-samples are collected in the 5mL falcon tubes. Surfaces should be swabbed thoroughly before placing the swab into the provided 2mL tube.

We cannot accept any swab or soil samples that are returned to us outside of the provided sterile containers. Samples provided outside of these containers (e.g. loose swabs, loose soil, or soil in ziplock bags) will not be processed.

Kit Contents

Sample kit with data label
Gloves
Soil mixing bag
5 mL vial(s)

Additional equipment

Small trowel, spoon or soil corer
Mobile phone or GPS device
Pen/permanent marker

Sterilisation materials for corer device between sites:

1:10 Bleach/Water solution in a spray bottle
Paper towel
Sterile water

Protocol

Step 1 – Gloves

Once at the site, put on your gloves.

Step 2 – Label tubes

Label each vial with the site code and replicate number using a permanent marker.
Place the labeled vials back into the kit bag.
Take a sterilised trowel to the first composite sampling location (e.g., the start of your transect).

Step 3 – Collect sub-samples

Collect at least 10 composite sub-samples at your sampling site.
Target the top 10 cm of soil, avoiding leaf litter or other debris.
Avoid sampling areas underfoot to prevent contamination from footwear.
Place each sub-sample into the mixing bag and mix thoroughly.

Step 4 – Fill sample vials

Once all sub-samples are collected and thoroughly mixed, fill each 5 mL vial from your sampling kit with soil from the mixing bag.
Use one vial per site replicate.

Step 5 – Seal and label kit

Seal the kit bag.
Record the key metadata on the bag, including:
- Site code
- Date
- Site coordinates (in decimal degrees)
- Any relevant notes
Ensure the site code on the bag matches the site code in the electronic Chain of Custody sheet, which must be submitted to EnviroDNA with your samples.

Step 6 – Sterilise equipment

After sampling at each site, sterilise the trowel following the protocols provided.
At the completion of all sampling, sterilise all equipment again to prepare for the next sampling period.

Step 7 – Send samples back

Store samples at 4 °C immediately after sampling (on ice or in fridge) and keep at this temperature until sent for analysis.
Send samples in vials back to EnviroDNA on ice (using cold chain logistics or in an esky with sealed freezer blocks) as soon as possible. Samples should be received within 5 days of sampling).
At the completion of all sampling, sterilise all equipment again to prepare for the next sampling period.

Sterilisation

1. Wearing gloves, spray the trowel (or spoon or soil corer) with 1:10 bleach-water solution all over.

2. Use paper towel to spread the bleach mixture and clean all parts that may have had contact with the soil. Thoroughly wipe excess bleach from the equipment using fresh paper towel until dry.

3. Rinse equipment thoroughly with sterile water three times to remove any residual bleach, as residual bleach will denature DNA and impact sample quality.

Sample storage

Soil samples should be sent to EnviroDNA as soon as possible after collection (receiving samples within 5 days of collection is strongly recommended). Between sampling and sending to EnviroDNA, eDNA soil samples should be refrigerated at 4°C. Do not freeze samples, as thawing in transit will accelerate degradation. Send soil samples on ice (using sealed ice packs only). Do not use loose ice, frozen produce, or snap lock bags ofice cubes – any ice will melt during transport and may destroy sample integrity.

Sample filters must be transported to EnviroDNA within 5 days of sampling:

EnviroDNA
Level 1, 95 Albert Street
Brunswick, VIC, 3056

The relevant project code must be included on the outside of the package and a digital copy of the metadata sheet attached to our submission form as soon as samples have been sent.