| Chemical Abstract Number (CAS #) |
76448
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| Synonyms | Heptachlor |
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4,7-Methano-1H-indene, 1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro- | Velsicol-104 | Drinox | Heptagran |
| Analytical Methods |
EPA Method 505 |
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EPA Method 508 |
EPA Method 525 |
EPA Method 608 |
EPA Method 617 |
EPA Method 625 |
EPA Method 8080A |
EPA Method 8081 |
EPA Method 8250A |
| Molecular Formula | C10H5Cl7 |
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| Use | INSECTICIDE FOR CONTROL OF COTTON BOLL WEEVIL FORMER USE
INSECTICIDE FOR TERMITE CONTROL (FORMER USE)
INSECTICIDE FOR CERTAIN FIELD CROPS-EG, CORN (FORMER USE)
INSECTICIDE FOR CITRUS CROPS (FORMER USE)
INSECTICIDE FOR FOLIAR & SEED TREATMENT (FORMER USE)
INSECTICIDE FOR PEST CONTROL OPERATORS (FORMER USE)
INSECTICIDE FOR PINEAPPLES & CEREAL (FORMER USE)
INSECTICIDE FOR VEGETABLES & SUGAR BEETS (FORMER USE)
INSECTICIDE FOR CERTAIN NUT CROPS (FORMER USE)
USUALLY ADDED TO SOIL TO CONTROL WHITE GRUBS, ROOT WEEVILS, &
WIREWORMS TO PREVENT GIRDLING OF SEEDLINGS BY REPRODUCTION OF
WEEVILS. MATERIAL IS EITHER SPRAYED ON PLANTED TREES OR TREES ARE
DIPPED IN WATER EMULSIONS OF ACTIVE CMPD PRIOR TO PLANTING. SRP:
FORMER USE IN USA
VET: AS PREMISE SPRAY AGAINST FLIES, FLEAS, MOSQUITOES, & THEIR LARVAE
BY USE OF RESIDUAL SPRAYS (0.125-0.5%). SRP: FORMER USE
Formulation of pesticides supplied as an emulsifiable concentrate, wettable powder, dust or
granular material; Used formerly as an insecticide in seed treatment, preplanting soil application,
dipping tops of plants and roots for control of insects, flies and mosquitoes; Used formerly on
household plots and on fruits; Used formerly in termite control (dispensed in caulking guns).
The only commercial use of heptachlor products still permitted is for fire ant control in power
transformers.
VET: AS PREMISE SPRAY AGAINST FLIES, FLEAS, MOSQUITOES, & THEIR LARVAE
BY USE OF RESIDUAL SPRAYS (0.125-0.5%). SRP: FORMER USE
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| Consumption Patterns | INSECTICIDE FOR NON-AGRICULTURAL USES, 100% (1983)
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| Apparent Color | WHITE ; White to light tan waxy solid
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| Odor | CAMPHOR-LIKE ODOR
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| Boiling Point | 145 DEG C @ 1.5 MM HG
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| Melting Point | 95-96 DEG C
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| Molecular Weight | 373.35
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| Density | 1.57 @ 9 DEG C
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| Odor Threshold Concentration | 0.02 PPM
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| Sensitivity Data | Eye Irritant.
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| Environmental Impact | The use of heptachlor in the United States was restricted to the control of fire ants in
power transformers and its release to the environment may result from this use and past extensive
pesticidal use prior to 1983. Release of heptachlor to soil surfaces will result in volatilization from
the surface, especially in moist soils, but volatilization of heptachlor incorporated into soil will be
slower. Hydrolysis in moist soils is expected to be significant. In soil, heptachlor will degrade to
1-hydroxychlordene, heptachlor epoxide and an unidentified metabolite less hydrophilic than
heptachlor epoxide. Biodegradation may also be significant. Heptachlor is expected to adsorb
strongly to soil and, therefore, to resist leaching to groundwater. Release of heptachlor to water
will result in hydrolysis to 1-hydroxychlordene (half-life of about 1 day) and volatilization.
Adsorption to sediments may occur. Biodegradation of heptachlor may occur, but is expected to
be slow compared to hydrolysis. Bioconcentration of heptachlor may be significant. Direct and
photosensitized photolysis may occur but are not expected to occur at a rate comparable to that
of hydrolysis. In air, vapor phase heptachlor will react with photochemically generated hydroxyl
radicals with an estimated half-life of 36 min. Direct photolysis may also occur.
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| Environmental Fate | AQUATIC FATE: Hepatochlor may undergo significant photolysis in ambient media,
since laboratory studies have demonstrated photolytic decomposition in 1 wk and complete
decomposition in 2 wk. The singlet oxygen reaction with heptachlor in aquatic media may be
significant, with the half-life of heptachlor est to be about 1 day. The hydrolysis of heptachlor in
aquatic media est hydrolytic half-life in the range of 1-3 days.
TERRESTRIAL FATE: LABELED HEPTACHLOR WAS APPLIED TO SOIL. ANALYSES
INDICATED PRESENCE OF 1-HYDROXYCHLORDENE, HEPTACHLOR EPOXIDE &
METABOLITE LESS HYDROPHILIC THAN HEPTACHLOR EPOXIDE.
TERRESTRIAL FATE: The half-life of heptachlor in soil was calculated to range from 0.4-0.8
years based on data collected in Mississippi, New Jersey and Beltsville, MD . The mean
disappearance rates of heptachlor from soil ranged from 5.25-79.5%/yr, depending upon the soil
type and mode of application of the insecticide . The highest rate was observed in sandy soil
following an application of a granule formulation. Soil incorporation also led to rapid
disappearance rates in all soil types . A water emulsion of heptachlor was applied to soils from
six states and quantified initially and after 12 months. The results were AR - 746-117 ppm, FL -
841-93 ppm, HI - 817-77 ppm, MD - 775- 122 ppm, MO - 758-103 ppm, OR - 741-156 ppm,
and SC - 774-62 ppm . In soil, heptachlor will degrade to 1-hydroxychlordene, heptachlor
epoxide and an unidentified metabolite less hydrophilic than heptachlor epoxide . Heptachlor is
expected to adsorb strongly to soil and, therefore, resist leaching to groundwater. Volatilization
from soil surfaces, especially wet ones, will be significant. Heptachlor incorporated into the soil
will resist volatilization. Hydrolysis of heptachlor in moist soils is expected to be significant.
Biodegradation may be important, especially under anaerobic conditions.
AQUATIC FATE: A river die away laboratory test was conducted with heptachlor in raw water
from the Little Miami River in Ohio. The river receives domestic and industrial wastes and farm
runoff. After 1 week, 75% of the initial heptachlor had disappeared and the heptachlor was 100%
degraded after 2 weeks . Chemical hydrolysis is expected to be the predominant fate of
heptachlor in water, with half-lives of 23.1 h in unbuffered water and 4.48 days at pH 7 in 99:1
water:ethanol . Bioconcentration in fish may also occur and volatilization of unadsorbed
heptachlor may be significant. Due to its high soil/sorption, coefficient, heptachlor is expected to
adsorb to sediments. Biodegradation may also be significant, but is expected to occur relatively
slowly compared to hydrolysis.
ATMOSPHERIC FATE: Based upon the vapor pressure, heptachlor is expected to exist almost
entirely in the vapor phase in ambient air . In the atmosphere, vapor phase reactions with
photochemically produced hydroxyl radicals and ozone may be important fate processes. The rate
constant for the vapor-phase reaction of heptachlor with photochemically produced hydroxyl
radicals has been estimated to be 6.57X10-11 cu cm/molecule-sec at 25 deg C, which corresponds
to an atmospheric half-life of about 6 hours at an atmospheric concn of 5X10 5 hydroxyl radicals
per cu cm . The rate constant for the vapor-phase reaction of heptachlor with ozone has been
estimated to be less than 2.0X10-16 cu cm/molecule-sec at 25 deg C which corresponds to an
atmospheric half-life of about 1.5 hours at an atmospheric concn of 7X10 11 molecules per cu
cm . In addition, heptachlor may directly photolyze in the vapor phase. The low water solubility
and the short atmospheric residence time of heptachlor indicates that physical removal from air by
wet deposition (rainfall and dissolution in clouds, etc.) is of limited importance.
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| Drinking Water Impact | DURING THE 1978 IRRIGATION SEASON, 14 GROUND WATER SAMPLES
WERE COLLECTED IN THE CENTRAL PLATEAU REGION OF NEBRASKA, AN AREA
KNOWN TO HAVE HIGH NITRATE-NITROGEN LEVELS, & ANALYZED FOR
PRESENCE OF 13 RESIDUES. LEVELS OF ORGANOCHLORINE INSECTICIDES
HEPTACHLOR & ITS DERIVATIVE, HEPTACHLOR EPOXIDE, WERE ALL BELOW THE
DETECTABLE LIMITS OF 0.005-0.010 UG/L.
HEPTACHLOR HAS RARELY BEEN FOUND IN SURFACE WATERS, & THEN ONLY IN
SMALL QUANTITIES: 5-30 PART PER TRILLION FOR HEPTACHLOR &/OR 5-40 PART
PER TRILLION FOR HEPTACHLOR EPOXIDE.
Heptachlor and heptachlor epoxide have been detected in private drinking wells at concentrations
of < 0.02 ug/l.
GROUNDWATER: New Jersey - 1,075 samples, 21.2% pos, 1.0 ppb max . Heptachlor was
detected but not quantified in groundwater samples in New Jersey , California and from
northern Italy . According to the EPA's Pesticides in Groundwater Database, hepatachlor was
detected in the groundwater supplies of the states of Kansas and Idaho at median concns of 0.03
and 0.02 ppb, respectively . During the 1978 irrigation season, 14 groundwater samples were
collected in the central plateau region of Nebraska, an area known to have high nitrate-nitrogen
levels, and were analzyed for her presence of 13 residues. Levels of the organochlorine
insecticide, heptachlor and its derivative, heptachlor epoxide, were all below the detectable limits
of 0,005 to 0.010 ug/L(6).
SURFACE WATER: Of the 4650 stations reporting heptachlor in ambient water in EPA's
STORET database, 34.0% contained detectable levels of the chemical with a median concn of
0.001 ug/l . Heptachlor was listed as a contaminant of the Great Lakes including Lakes Ontario,
Erie, Huron, Michigan and Superior . In 1980, heptachlor was detected in the waters of Lake
Pontchartrain Inner Harbor Navigation Canal at a concn of 0.6 ng/l at an ebb tide of 1.5 m and at
concns ranging from 9.1 to 9.3 ng/l at flood tides of 1.5 to 10 m . Heptachlor was detected with
a 21.4% frequency of occurrence for 604 samples of surface waters from New Jersey collected
from 1977 to 1979 .
SURFACE WATER: Heptachlor was detected in Mississippi River water at Louisiana at concns
ranging from undetected levels to 2.4 ng/l for the summer to winter of 1974 . Mediterranean
waters off the coast of Morocco contained heptachlor at concns ranging from trace quantities to
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