| Chemical Abstract Number (CAS #) |
82688
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| Synonyms | Pentachloronitrobenzene |
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PCNB | Terraclor | Quintozene | Benzene, pentachloronitro- |
| Analytical Methods |
EPA Method 617 |
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EPA Method 8081 |
EPA Method 8250A |
| Molecular Formula | C6Cl5NO2 |
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| Use | SLIME PREVENTION IN INDUSTRIAL WATER; HERBICIDE
FUNGICIDE FOR LAWNS, TURF, SEED TREATMENT OF FIELD CROPS,
VEGETABLES, & OTHER FIELD CROPS-EG, SOYBEANS
APPROVED IN USA FOR USE AS SOIL FUNGICIDE ON ORNAMENTAL CROPS
(EG, CARNATIONS, GRASSES, LILIES & ROSES) & AS TREATMENT FOR USE ON
WIDE VARIETY OF SEEDS (EG, BARLEY, CORN, COTTON, OATS, RICE & WHEAT).
INTRODUCED AS 15% DUST (NOW 20%) (TRITISAN) FOR SEED TREATMENT OF
WHEAT AGAINST BUNT & AS 20% DUST (BRASSICOL) AS SOIL FUNGICIDE. THE
20% DUST IS EFFECTIVE AGAINST BOTRYTIS ON LETTUCE (BOTRILEX).
/BOTRILEX (20% DUST) & BRASSICOL (20% DUST) ARE EFFECTIVE FOR
CONTROL OF SNOW MOLD OF RYE & OTHER LOW-TEMPERATURE FUNGI
EFFECTIVE AS SOIL FUNGICIDE ON CERTAIN SPECIES OF RHIZOCTONIA &
SCLEROTINIA.
Used for damping off of cotton; black root and club root of cabbage, cauliflower, brussels
sprouts, and broccoli potatoes; southern stem and root rot of peanuts; southern blight of
tomatoes and peppers; root and stem rot and white mold of beans; white rot of garlic; bunt of
wheat; botrytis storage rot of roses; brown patch and snow mold of turf; petal blight of azaleas;
root rot of easter lilies; flower blight of camellia; stem rot of various ornamentals; and crown and
black rot of bulbous ornamentals
Used on cabbage during soil treatment against club root (plasmodiophora). 101 Brand PCNB
75 Wettable
Used on avocados during soil and seed treatment against rhizoctonia. Olin Terraclor 75%
Wettable Powder
Used on ornamental turf and lawns during foliar treatment against snow mold (fusarium). Olin
Terraclor 75% Wettable Powder
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| Consumption Patterns | FUNGICIDE FOR PEANUTS, 47%; SEED TREATMENT FOR FIELD CROPS, 11%;
POTATOES, 3%; VEGETABLES, 3%; OTHER FIELD CROPS-EG, SOYBEANS, 21%;
LAWNS & TURF, 16% (1982)
QUINTOZENE USAGE IN CALIF, MAJOR AGRICULTURAL STATE, WAS 22,000 KG
IN 1971 & 25,000 KG IN 1972 OVER 70% WAS APPLIED TO COTTON & ABOUT
8% WAS USED FOR COTTONSEED TREATMENT.
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| Apparent Color | CRYSTALS FROM ALCOHOL; COLORLESS NEEDLES; FINE NEEDLES
FROM ALCOHOL, PLATELETS FROM CARBON DISULFIDE
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| Odor | MUSTY ODOR
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| Boiling Point | 328 DEG C AT 760 MM HG WITH SOME DECOMPOSITION
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| Melting Point | 144 DEG C
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| Molecular Weight | 295.36
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| Density | 1.718 AT 25 DEG C/4 DEG C
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| Environmental Impact | Pentachloronitrobenzene (PCNB) is used as an intermediate, herbicide, fungicide for
seed and soil treatment, and as a slime inhibitor in industrial waters. PCNB released to soil is not
expected to leach extensively. Field and laboratory half-lives for PCNB in soil vary from several
weeks to almost 2 years. Volatilization may be the most significant loss mechanism for PCNB
from aerobic soils, followed by biodegradation. In a anaerobic soil, PCNB loss was principally by
conversion to pentachloroaniline (PCA). PCNB released to water will sorb to sediments,
suspended sediments, and biota. An estimated Henry's Law Constant for PCNB indicates that
volatilization from water may be significant; however, sorption of PCNB to organic particulate
matter in water will decrease the significance of volatilization. PCNB will have a low to moderate
tendency to bioconcentrate (BCF in fish 200-1200). Photolysis and hydrolysis of PCNB are
probably not significant degradative processes. Biodegradation appears to be relatively slow;
however, it may be a significant degradative process for PCNB in water. No information was
found on the fate of PCNB in the atmosphere; however, it will probably adsorb to particulate
matter and thus may be removed from the atmosphere by wet and dry deposition. PCNB
has been found in drinking water, well water, crop land and nursery soils, spinach leaves, cheese,
fruits, ground grains, leaf and stem vegetables, nuts, and oilseed by-products. The most probable
route of human exposure to PCNB will probably be through the ingestion of contaminated food.
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| Environmental Fate | TERRESTRIAL FATE: Pentachloronitrobenzene (PCNB) released to soil is not
expected to leach extensively. Numerous soil fate studies have been conducted on PCNB. The %
distribution of PCNB in a terrestrial microcosm chamber, when applied as a coating on alfalfa and
ryegrass seeds, was: 59 (soil), 24 (air), 16 (plants), 0.3 (groundwater), 0.06 (animals), and 0.7
(misc) . PCNB half-lives (and corresponding application rate, kg/ha) in laboratory soil
experiments were: 699 days (60), 213 days (60), 535 days (10), and 425 days (10) . Average
PCNB half-life in 2 field locations (different soil types) in Denmark was 434 days . PCNB loss
in 3 California soils in laboratory experiments followed first-order kinetics . The half-life of
PCNB was 4.7, 7.6, and 9.7 months for Columbia fine sandy loam, Sacramento clay, and Staten
peaty muck, respectively . PCNB (50 ug PCNB/5 g dry soil) rapidly disappeared from
submerged soil . After 3 weeks of incubation, less than 1% of the originally applied PCNB
remained in submerged soil, whereas 82% of the original PCNB persisted in moist soil. PCNB
remained unchanged in sterilized, moist soil; however, about 44% of the PCNB disappeared from
sterilized, submerged soil after 3 weeks. Loss of PCNB in nonsterilized submerged or moist soil
was accompanied by an increase in pentachloroaniline (PCA), but no PCA was detected in
sterilized submerged soil . In another laboratory study, PCNB (5 mg PCNB 50 g air dry soil)
loss was determined in Yolo fine sandy loam . After 10 months in both sterilized and
unsterilized soil, 80% of the applied PCNB was lost from the soil. Removal in the air stream
accounted for 62% of the PCNB while the remaining 18% was attributed to microbial and
chemical degradation. Undegraded PCNB was the major component recovered in the air
stream . In a laboratory study using Hagerstown silty clay loam under anaerobic conditions (40
day incubation), PCNB loss was principally by conversion to pentachloroaniline (PCA) with some
loss by volatilization and conversion to pentachlorothioanisole (PCTA) and pentachlorophenol
(PCP)(6). Radiolabeled (14C) PCNB was used to study PCNB fate and distribution in Matapeake
silt loam. PCNB concentration in the soil was 5.0 ppm and incubation was at 25 deg C for 60
days. The percent 14C recovered and its source was: 67.2 as PCNB, 10.3 as pentachloroaniline
(PCA), 8.2 as pentachlorothioanisole (PCTA), and 14.3 of unknown origin(7). In soil treated with
PCNB and incubated at 30 deg C, 40-58% of the PCNB degraded in 18 weeks; however, no
mineralization occurred(8). PCNB residues decreased from 14.6 to 2.20 ppm in 6 months in a
lettuce area in Germany. Brassicol (PCNB) was applied according to producers
recommendations(9). In a study conducted in Japan, 2 kg PCNB/ha was applied and mixed into
the top 10 cm of soil (lithosole and gray lowland soil). After 1 month, 5% of the PCNB had
degraded in the top 5 cm; after 8.4 months, 100% had degraded(10).
AQUATIC FATE: Pentachloronitrobenzene (PCNB) added to artificial ponds had a half-life in
the water of 1.8 days . The exponential decrease of PCNB concentration in the water phase was
due to volatilization, adsorption to seston, absorption by biota and subsequent sedimentation as
detritus . Photolysis and hydrolysis of PCNB are probably not significant degradative
processes. Based upon degradation in soil, PCNB may undergo microbial transformations
in aquatic systems. However, mineralization of the resulting biotransformation products will
probably be slow. Biodegradation of PCNB may be an important degradative process.
ATMOSPHERIC FATE: No information was found about the fate of pentachloronitrobenzene
(PCNB) in the atmosphere; however, it will probably adsorb to particulate matter and thus may be
removed from the atmosphere by wet and dry deposition.
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| Drinking Water Impact | DRINKING WATER: Pentachloronitrobenzene (PCNB) was found in Cincinnati
drinking water at an unspecified concn. .
GROUND WATER: Pentachloronitrobenzene (PCNB) was found in California well water at an
unspecified concn. .
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