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Picloram in Drinking Water - Frequently Asked Questions

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General information about picloram and its health effects

What is picloram and where does it come from?
Picloram is a man-made herbicide widely used for killing weeds along roadways and ditch banks and on non-productive land, forest land and commercial or industrial properties. As a restricted use pesticide, it is not available for homeowner use.
What are picloram's trade names and synonyms?
Tordon K, Tordon 22K, Outpost 22K, Trooper, Triumph 22K, Picloram K, Terva 22K, Picloram +D, Grazon P+D, Hired Hand P+D, Pathway, Sekor P+D, Surmount, Tordon 101, Tordon RTU, Trooper Pro, Trooper P+D
When does picloram in drinking water become a health concern?
Picloram is measured in parts per billion (ppb). The federal government has established the safe drinking water standard, also called maximum contaminant level (MCL), for picloram as 500 ppb. If your water has picloram levels above 500 ppb, it is advisable to switch to bottled water.
How can picloram affect my health?
Picloram is a potential health hazard. Continued exposure to drinking water that has levels of picloram above its MCL can cause adverse health effects such as:
  • Weakness;
  • Diarrhea;
  • Weight loss;
  • Liver damage; and
  • Damage to central nervous system.
The most recent research finds no evidence that picloram is carcinogenic in humans.
Is picloram found in Oregon's drinking water systems?
Picloram was detected in less than one-tenth of one percent of public water systems in the past several years. All detections were at least 1000 times less than the MCL.

Safely using picloram-contaminated water

Can I wash my food with picloram-contaminated water?
If picloram levels in your water are above 500 ppb, you should use bottled water to wash, prepare and cook your food.
Can I irrigate or water my garden with picloram-contaminated water?
Since picloram is an herbicide designed to kill plants, you should not use picloram-contaminated water for irrigation as it could kill your vegetables, fruit or ornamentals.
What about bathing and showering?
Picloram does not easily enter the body through the skin. Bathing, swimming and showering with picloram-contaminated water are safe as long as you avoid swallowing the water. Supervise small children when they are bathing and brushing teeth to ensure they do not swallow the water.
Washing dishes, utensils and food preparation areas:
Only a very small amount of water clings to smooth surfaces, like dishes. Water having picloram contamination can be safely used to wash and sanitize dishes, tables and eating utensils.
General cleaning and laundry:
Very little water remains on washed surfaces and in laundered fabrics. Because these articles are not placed in the mouth, water having picloram contamination can be safely used for general cleaning and washing of clothing, bedding and linens.
What about my pets?
Animals should not drink water with picloram levels above 500 ppb.

Learning about picloram levels in your drinking water

For people on municipal or public water systems:
Public drinking water providers are required to monitor for picloram and ensure levels remain below the drinking water standard of 500 ppb. They are also required to make those results public. If your water comes from a public water system (i.e., you pay a water bill), you can find results on the Oregon Drinking Water Services Data Online website. Your drinking water provider may also be required to provide a Consumer Confidence Report to its customers every year. This report contains the most recent picloram test results. Contact your drinking water provider for a copy of the most recent consumer confidence report.
For private well owners:
If your drinking water comes from your own well, you will need to find an accredited laboratory that does water testing for private property owners. These labs can provide information and instructions for getting your well water tested. For a list of accredited laboratories in Oregon, contact the Oregon Environmental Laboratory Accreditation Program (ORELAP) or view the list online: ORELAP Accredited Laboratories (pdf).

Removing picloram from drinking water

For public drinking water system operators:
Picloram can be reduced to below 500 ppb in drinking water using granular activated carbon filtration. We recommend that you work with a contractor to determine the most appropriate treatment for your system. Treatment has limitations and disadvantages. Not all kinds of treatment are effective, and no single treatment method can remove all contaminants from water. If treatment isn't possible for your system, you should consider developing a different water source or connecting to another safe water source in the area.
Water that is to be used for drinking, beverage-making or food preparation can be obtained from a known safe source and used on a temporary basis. Non-ingestion uses of water pose much less hazard, but might not be entirely safe if picloram levels are significantly above its drinking water MCL. Before deciding on treatment equipment, contact Oregon Drinking Water Services for information and advice.
For private well owners:
Don't boil the water!
There is no evidence that boiling contaminated water removes picloram.
Private well treatment options:
Treatment options are available to remove picloram from well water. The one most commonly used is called granular activated carbon filtration. We recommend either central treatment or a point-of-entry treatment in a private residence. Costs may be reduced with a point-of-use device (e.g., kitchen sink filter).
Treatment equipment must be carefully maintained in order to work properly and might not be effective if picloram levels are very high. It is recommended that treated water be tested at least once a year. Untreated water should be tested at least every 3 years.
Check to be sure that any treatment system to be used is certified by a recognized, third-party testing organization that meets strict testing procedures established by the American National Standards Institute (ANSI) and National Sanitation Foundation (NSF) International.

For more information

Updated:February 2012