Technical Factsheet on: ENDOTHALL
List of Contaminants
As part of the Drinking Water and Health pages, this fact sheet is part of a larger publication:
National Primary Drinking Water Regulations
Drinking Water Standards
MCLG: 0.1 mg/L
MCL: 0.1 mg/L
HAL(child): 1- to 10-day: 0.8 mg/L; Longer-term: 0.2 mg/L
Health Effects Summary
Acute: EPA has found endothall to potentially cause the following
health effects from acute exposures at levels above the MCL:
depressed breathing and heart rate.
Drinking water levels which are considered "safe" for short-term
exposures: For a 10-kg (22 lb.) child consuming 1 liter of water
per day, upto a ten-day exposure to 0.8, or up to a 7-year
exposure to 0.2 mg/L.
Chronic: Endothall has the potential to cause the following
health effects from long-term exposures at levels above the MCL:
increased organ weights and organ-to-body weight ratios of
stomach and intestine.
Cancer: There is inadequate evidence to state whether or not
endothall has the potential to cause cancer from a lifetime
exposure in drinking water.
Usage Patterns
Endothall is used as a defoliant for a wide range of crops and as
a herbicide for both terrestrial and aquatic weeds. It is used as
a desiccant on lucerne and on potato, for the defoliation of
cotton, to control aquatic weeds and as an aquatic algicide
growth regulator. It has been used for: sugar beets, turf, hops
sucker suppression; alfalfa, clover desiccants; potato vine
killers.
EPA estimated total domestic usage in 1982 to have been
approximately 1.5 million lbs. In California in 1984, 87,000 lbs.
of the mono(N,N-diethylalkylamine) salt were used; 4,000 lbs. of
the dimethylamine salt were used; minor amounts of the
dimethylalkylamine and dipotassium salts were used. Its estimated
applications in California were as follows: Cotton production,
95.6%; Sugarbeets, 3.9%; Remainder in landscape maintenance or
"public health pest control."
Release Patterns
Release of endothall to the environment is expected to occur
primarily during its use as a pre-emergence, post-emergence, turf
and aquatic herbicide and harvest aid. Other sources of release
include loss during manufacturing, formulation, packaging or
disposal of this herbicide.
Since endothall is not a listed chemical in the Toxics Release
Inventory, data on releases during its manufacture and handling
are not available.
Environmental Fate
If released to soil, endothall is expected to rapidly biodegrade
under aerobic conditions. The half-life of endothall in soil is
reported to be 4 to 9 days. Endothall should be highly mobile in
soil; however, rapid degradation would limit the extent of
leaching. Its persistence in soil may be prolonged by adsorption
to organic matter or by factors inhibiting microbial activity.
Chemical hydrolysis and volatilization are not expected to be
significant.
If released to water, endothall should rapidly biodegrade under
aerobic conditions (half-life approximately 1 week or less) and
biodegrade more slowly under anaerobic conditions. Glutamic acid
is a major biotransformation product of endothall under aerobic
conditions. Endothall is not expected to oxidize, chemically
hydrolyze, photolyze, volatilize or adsorb to suspended solids or
sediments in water. The soil adsorption coefficient (Koc) of
endothall in sediment/water systems has been measured to be < 2.
If released to the atmosphere, endothall is expected to exist
predominantly on particles and should either settle out or wash
out in precipitation. It is not expected to chemically react or
photolyze in the atmosphere.
The whole body bioconcentration factor (BCF) of endothall in
bluegill (Lepomis macrochirus) has been measured to be < 1. Based
on a its water solubility, a BCF of < 1 has also been calculated.
With these BCF values, endothall is not expected to bioaccumulate
in aquatic organisms.
The most probable routes of human exposure to endothall are
inhalation and dermal contact of workers involved in the
manufacture, handling or application of endothall. The general
public could potentially be exposed through use for lawn weed
control.
Chemical/ Physical Properties
CAS Number: 145-73-3
Color/ Form/Odor: Odorless, white crystals
M.P.: 144 C (decomposes)
Vapor Pressure: very low at room temp.
Octanol/Water Partition (Kow): N/A
Density/Spec. Grav.: 1.431 at 15 C
Solubility: 100 g/L of water at 20 C; Very soluble in water
Soil sorption coefficient: Koc <2; high mobility in soil
Odor/Taste Thresholds: N/A
Henry's Law Coefficient: N/A
Bioconcentration Factor: BCF <1 in fish; not expected to
bioconcentrate in aquatic organisms.
Trade Names/Synonyms:
Hexahydro-3,6-endo-epoxy-1,2-benzenedicarboxylic acid;
Accelerate; Aquathol; Des-i-cate; Endothall Turf Herbicide;
Endothall Weed Killer; Herbicide 273; Hydrothol; Herbon Pennout;
Hydout.
Other Regulatory Information
Monitoring For Ground/Surface Water Sources:
- Initial Frequency- 4 quarterly samples every 3 years
- Repeat Frequency- If no detections during initial round:
- 2 quarterly per year if serving >3300 persons;
- 1 sample per 3 years for smaller systems
- Triggers - Return to Initial Freq. if detect at > 0.009 mg/L
Analysis:
| Reference Source |
Method Numbers |
| EPA 600/4-88-039 |
548.1 |
Treatment- Best Available Technologies:
Granular Activated Charcoal
For Additional Information:
EPA can provide further regulatory and other general information:
EPA Safe Drinking Water Hotline - 800/426-4791
Other sources of toxicological and environmental fate data include:
Toxic Substance Control Act Information Line - 202/554-1404
Toxics Release Inventory, National Library of Medicine - 301/496-6531
Agency for Toxic Substances and Disease Registry - 404/639-6000
National Pesticide Hotline - 800/858-7378
List of Contaminants
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