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Clean off invasive species from your outdoor gear - Tips for scientists
Photo credit: © Nathan Rank/Flickr

Tips for Scientists

(Vernal Pool Equipment Cleaning Protocols)


Diseases are increasingly recognized as serious threats to wildlife populations. The two main players in vernal pool ecosystems are Ranavirus (RV) and fungal pathogens such as the chytrid fungus, also known as Bd, (Batrachochytrium dendrobatidis), and the Bsal fungus (Batrachochytrium salamandrivorans).


Both of these diseases have been documented in Pennsylvania. They can cause large die-offs among both reptiles and amphibians.  Outbreaks may be induced by an accumulation of environmental stresses including habitat degradation and use of pesticides and other chemicals.  Spores and contaminated soils can be spread by wildlife, but also by humans, especially outdoor recreationists, construction workers, scientists, land owners, and land managers who carry spores and contaminated soils on their boots, in the tread of tires, or on equipment.


You can take a few simple measures to prevent inadvertently moving diseases or invasive plants and animals from place to place.  First and foremost, don’t move animals from one location to another, or release pet reptiles and amphibians into the wild.  Second, it is important to clean and disinfect gear between sites.  Rubber-soled footwear such as muck boots are best for field work because they are the easiest to properly disinfect.

Disinfectant Technique
  • Take your gear and anything else that touched the water away from the wetland or stream. Rinse equipment with water and scrub away loose dirt, vegetation, algae, etc.

  • Apply a disinfectant solution to the gear (two options are given below).

  • Rinse gear with plain water and let dry (in the sun, if possible) for five minutes.

Disinfectant Solutions

Household bleach

  • To mix a gallon: add 1/2 cup bleach to 1 gallon of water.

  • Effective dilution ratio for RV and Bd - 1:32 bleach:water (3% solution) using standard 6% concentration household bleach.

  • Shelf life: Solutions last one month if kept tightly sealed in an opaque container. If exposed to sunlight and air, the solution only lasts five days.

  • Pros: Cheap and convenient.

  • Cons: Bleach is damaging to clothing and equipment.

  • Neutralizing bleach: Stop the corrosive action of bleach by treating disinfected gear with an 800 ppm solution of sodium thiosulfate. Mix 3 grams of sodium thiosulfate into a gallon of water. Apply to gear that has been bleached and rinsed. Wait several minutes, then rinse gear thoroughly with water. Sodium thiosulfate is available online or from some pool supply stores.


  • To mix a gallon: add 2 tablespoons of Nolvasan to 1 gallon water.

  • Effective dilution ratio for RV and Bd - 1:127 Nolvasan:water (0.75% solution), using 2% concentration Chlorhexidine diacetate.

  • Shelf life: Can store the liquid concentrate for 36 months. Solution made with tap water is stable for 1 week (but up to 6 weeks with deionized water).

  • Pros: A small amount creates a gallon of solution. Doesn't damage gear like bleach.

  • Cons: More expensive than bleach.


  • To mix a gallon: Add 1 scoop of powder per gallon of water - for a 1.0% solution.

  • Shelf life: Can store the powder for 3 years, and tablets for 2 years. Solution made with tap water is stable for 1 week.

  • Pros: A small amount creates a gallon of solution. Doesn’t damage gear like bleach.

  • Cons: More expensive than bleach.


Previous vernal pool equipment cleaning recommendations mention a ‘dry gear’ technique for cleaning equipment, which simply involves letting equipment dry for a minimum of 48 hours at 70% or lower humidity, preferably in full sun, until it is completely dry. This technique is effective for some (but not all) aquatic invasive species and pathogens.  However, it is not effective against Ranavirus which can persist in wet and dry environments for over 90 days.  In light of the threat this deadly virus poses to our native amphibians, reptiles, and fish, the 'dry gear' technique is no longer a recommended equipment cleaning protocol.

Information on this page is provided by the Pennsylvania Natural Heritage Program

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