This is a fact sheet about a chemical that may be found in some public or
private drinking water supplies. It may cause health problems if found
in amounts greater than the health standard set by the United States
Environmental Protection Agency (EPA).
What is Endrin and how is it used?
Endrin is an organic solid of odorless white crystals. Endrin is an
insecticide which has been used mainly on field crops such as cotton,
maize, sugarcane, rice, cereals, ornamentals, and other crops. It has
also been used for grasshoppers in non-cropland and to control voles and
mice in orchards. Once widely used in the US, most uses were canceled in
The list of trade names given below may help you find out whether you
are using this chemical at home or work.
Trade Names and Synonyms:
Why is Endrin being regulated?
In 1974, Congress passed the Safe Drinking Water Act. This law requires
EPA to determine safe levels of chemicals in drinking water which do or
may cause health problems. These non-enforceable levels, based solely on
possible health risks and exposure, are called Maximum Contaminant Level
The MCLG for endrin has been set at 2 parts per billion (ppb)
because EPA believes this level of protection would not cause any of the
potential health problems described below.
Based on this MCLG, EPA has set an enforceable standard called a
Maximum Contaminant Level (MCL). MCLs are set as close to the MCLGs as
possible, considering the ability of public water systems to detect and
remove contaminants using suitable treatment technologies.
The MCL has been set at 2 ppb because EPA believes, given present
technology and resources, this is the lowest level to which water
systems can reasonably be required to remove this contaminant should it
occur in drinking water.
These drinking water standards and the regulations for ensuring
these standards are met, are called National Primary Drinking Water
Regulations. All public water supplies must abide by these regulations.
What are the health effects?
Short-term: EPA has found endrin to potentially cause the following health
effects when people are exposed to it at levels above the MCL for
relatively short periods of time: tremors, labored breathing, mental
Long-term: Endrin has the potential to cause the following effects
from a lifetime exposure at levels above the MCL: convulsions and damage
to liver tissue.
How much Endrin is produced and released to the environment?
Production in 1980 was reported to be 100,000 lbs. Endrin's former source
in the environment is from use as an insect, bird and rat-killer. It has
been used on agricultural crops, cotton seeds, control of birds on
buildings and mice in orchards. Its major use has been on cotton crops.
The EPA presently considers the pesticide canceled.
What happens to Endrin when it is released to the environment?
Endrin is very persistent, but it is known to be broken down by sunlight.
Endrin released to soils will persist for up to 14 years or more. Its
strong adsorption to soil makes leaching into groundwater unlikely.
However, the detection of endrin in certain groundwater samples suggest
that leaching may be possible in some soils. Endrin released to water
systems will also persist, mainly in sediments.
It has a very high potential to accumulate in fish and shellfish.
How will Endrin be detected in and removed from my drinking
The regulation for endrin became effective in 1992. Between 1993 and 1995,
EPA required your water supplier to collect water samples every 3 months
for one year and analyze them to find out if endrin is present above
0.01 ppb. If it is present above this level, the system must continue to
monitor this contaminant.
If contaminant levels are found to be consistently above the MCL,
your water supplier must take steps to reduce the amount of endrin so
that it is consistently below that level. The following treatment
methods have been approved by EPA for removing endrin: Granular
How will I know if Endrin is in my drinking water?
If the levels of endrin exceed the MCL, 2 ppb, the system must notify the
public via newspapers, radio, TV and other means. Additional actions,
such as providing alternative drinking water supplies, may be required
to prevent serious risks to public health.
This is a factsheet about a chemical that may be found in some
public or private drinking water supplies. It may cause health problems
if found in amounts greater than the health standard set by the United
States Environmental Protection Agency (EPA).
Drinking Water Standards:
Note: This fact sheet is part of a larger publication
adapted from U.S. EPA publication: EPA National Primary Drinking Water
|Mclg: 2 ppb (parts per billion)
Mcl: 2 ppb