| Chemical Abstract Number (CAS #) |
87650
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| Synonyms | 2,6-Dichlorophenol |
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Phenol, 2,6-dichloro- |
| Analytical Methods |
EPA Method 8040A |
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EPA Method 8250A |
| Molecular Formula | C6H4Cl2O |
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| Use | CHEM INT FOR TRI, TETRA, AND PENTACHLOROPHENOLS
DEHYDRO-L-ASCORBIC ACID HAS BEEN PREPARED BY UV IRRADIATION AND BY
OXIDATION WITH 2,6-DICHLOROPHENOL
The sex pheromone, 2,6-dichlorophenol, was combined with a pesticide to control populations
of the American dog tick, Dermacentor variabilis (Say). This pheromone persisted in the fur of
treated dogs for at least 18 days. The mixture of pheromone and pesticide was much more
effective in reducing mating among the surviving ticks than the treatments without pheromone.
The pheromone pesticide mixture also killed significantly more ticks than the treatment without
pheromone. This increased effectiveness was due almost entirely to the significantly greater kill of
male ticks. Combining the sex pheromone with pesticide treatments offers a means of suppressing
tick populations by curtailing their mating and subsequent reproductive success.
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| Apparent Color | NEEDLES FROM PETROLEUM ETHER
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| Boiling Point | 219-220 DEG C @ 740 MM HG; 80-85 DEG C @ 4 MM HG
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| Melting Point | 68-69 DEG C
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| Molecular Weight | 163.0
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| Odor Threshold Concentration | In water 102 ug/l (mean value calculated from reported odor thresholds in other
literature) Purity not specified
Odor Threshold: Detection: 0.003 mg/kg; 0.0075 mg/kg; 0.2 mg/kg Purity not specified
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| Sensitivity Data | A skin irritant
Irritating to eyes, nose, and throat.
TRICHLOROPHENOLS PRODUCE REDNESS & EDEMA ON SKIN CONTACT . IN
EYE THEY INDUCE CONJUNCTIVAL IRRITATION & SOMETIMES CORNEAL INJURY
& IRITIS. DUSTS ARE IRRITATING TO NOSE & PHARYNX. TRICHLOROPHENOL/
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| Environmental Impact | 2,6-Dichlorophenol may be released to the environment in effluents from chlorination
processes (in which it is inadvertently formed) involving water treatment and wood pulp
bleaching. Releases may also result from various incineration processes or from waste releases
involving production of 2,4-dichlorophenol. If released to the atmosphere, degradation can occur
by reaction with photochemically formed hydroxyl radicals (estimated avg half-life of 5.3 days).
Physical removal from air may occur via rainfall. With a pKa of 6.8, 2,6-dichlorophenol can exist
in both the non-dissociated and ionized forms in environmental soil and water depending upon the
pH of the media. If released to soil, the ionized form may adsorb poorly to soil material, and
therefore leach. Sufficient experimental data are not available to accurately estimate the
leachability of the non-dissociated form. Various biodegradation studies have demonstrated that
2,6-dichlorophenol is significantly degradable under aerobic conditions, but only poorly
degradable or resistant to degradation under anaerobic conditions. Biodegradation under aerobic
conditions may be the most important environmental fate process in soil. If released to water,
adsorption to sediments may be significant under various conditions since one monitoring study
found a higher concn of 2,6-dichlorophenol in sediments than in the associated water column.
Photo-oxidation in sunlit natural water may have some importance as a chemical degradation
process. The general population can be exposed to 2,6-dichlorophenol through oral consumption
or dermal contact with chlorinated tap water or by inhalation of air contaminated by incineration
processess.
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| Environmental Fate | Terrestrial Fate: Contamination of soil in the vicinity of two Finnish sawmills using
preservative (Ky-5) against blue staining fungi that contained chlorophenols was studied. The soil
around the treatment basins contained up to 70 mg chlorophenols/kg and that in the storage area
for treated lumber up to 6 mg/kg. Contamination extended to a depth of at least 2 m near the
treatment basins. Surface water inside the sawmill area contained the same chlorophenols as those
used in wood preservation, plus some additional isomers. The ground water and lake water
around the sawmill areas were contaminated. 2,6-Dichlorophenol was one of several chlorinated
phenols detected. The fate of different chlorophenols in soil is probably affected by many factors,
such as the water solubility of each chlorophenol, pH of the soil, rainfall, soil organic matter
content, type and particle size of the soil, biological and photodegradation and the evaporation of
each chlorophenol.
Emmissions, bioaccumulation, and possible food chain enrichment of polychlorinated phenols,
including 2,6-dichlorophenol were studied by analyses of water, snow, ash, benthic animal, fish,
and bird samples in Finland. Although the enrichment potential of the studied compounds
appeared to be lower than the chlorinated hydrocarbons, they proved to be very general pollutants
and some of them showed specific bioaccumulation in certain species and high persistency, thus
forming environmental hazards.
The disappearance rate of 2,6-dichlorophenol in a small stream was studied and showed to be
first order with respect to either distance or time of flow. Average half-life in the stream was
about 4 hours. It is suggested that the disappearance was due to degradation within the biofilm
covering the stream bed and that the rate is controlled by diffusion of 2,6-dichlorophenol across
the water biofilm interface.
TERRESTRIAL FATE: The adsorption of 2,6-dichlorophenol by soil material depends, in part,
upon the pH of the soil(1,2). With a pKa of 6.8 , 2,6-dichlorophenol can exist in environmental
media in both the non-dissociated and ionized forms. In highly alkaline soils (pH 10), it will be in
primarily the ionized form and has been observed to be poorly adsorbed to soil under such
conditions . Non-dissociated 2,6-dichlorophenol is expected to undergo more adsorption than
the ionized form(1,2). A log Kow of 2.64 suggests that the non-dissociated form will have
medium soil mobility; however, sufficient experimental data are not available to accurately predict
actual leachability in many soil systems. Various biodegradation studies have demonstrated that
2,6-dichlorophenol is significantly degradable under aerobic conditions, but only poorly
degradable or resistant to degradation under anaerobic conditions. Biodegradation under aerobic
conditions may be the most important environmental fate process in soil.
AQUATIC FATE: With a pKa of 6.8, 2,6-dichlorophenol can exist in both the non-dissociated
and ionized forms in environmental waters depending upon the pH of the water. Under highly
alkaline conditions (pH 10), the ionized form has been observed to be poorly adsorbed to soil
materials which suggests that the ionized form may not partition from the water column to
aquatic sediments. However, in one monitoring study, the concn of 2,6-dichlorophenol was found
to be greater in the aquatic sediments than in the associated water column which indicates that
adsorption may be significant under various conditions. By analogy to phenols as a chemical
class , 2,6-dichlorophenol may be susceptible to significant photo-oxidation (via peroxy and
hydroxyl radicals) in sunlit natural water; however, kinetic rate data are not available to predict
relative importance. Various soil biodegradation studies have shown that 2,6-dichlorophenol is
degradable under aerobic conditions, but only poorly degradable (or resistant) under anaerobic
conditions. Aquatic hydrolysis and volatilization are not expected to be important.
ATMOSPHERIC FATE: Based on an extrapolated vapor pressure of 0.036 mm Hg at 25 deg
C(1,SRC), 2,6-dichlorophenol can be expected to exist almost entirely in the vapor-phase in the
ambient atmosphere(2,SRC). Vapor-phase 2,6-dichlorophenol is degraded in the ambient
atmosphere by reaction with photochemically formed hydroxyl radicals; the half-life for this
reaction in typical air can be estimated to be about 5.3 days(3,SRC). Direct photolysis in air may
be possible, but kinetic rate data are not currently available to predict its relative significance.
2,6-Dichlorophenol has been detected in rainwater from Portland, OR ; therefore, physical
removal from air by means of wet deposition may have some importance.
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| Drinking Water Impact | PRODUCTION MECHANISMS OF CHLOROPHENOLS BY CHLORINATION IN
DISINFECTION OF WATER & DETERMINATION OF POLLUTION LEVELS OF
PHENOLS AS PRECURSOR OF CHLOROPHENOLS, & CHLOROPHENOLS IN SEWAGE,
STREAM WATER & TAP WATER IN THE VICINITY OF SEOUL, KOREA FROM JAN TO
SEPT, 1979 WAS STUDIED. CHLORINATED PHENOLS CAN BE PRODUCED BY THE
CHLORINATION OF PHENOL WITH HYPOCHLORITE IN WATER. CHLOROPHENOLS/
SURFACE WATER: 2,6-Dichlorophenol was detected in 69% of 13 water samples taken from
the Ijssel River (Netherlands) in 1979 with a maximum and median concn of 0.26 and 0.09 ppb,
respectively . Maximum concentrations ranging from 0.06 to 0.45 ppb were detected in the
Rhine River (at Lobith) and other Dutch rivers during 1976 and 1977 monitoring .
2,6-Dichlorophenol levels ranging from 0.3 to 1.8 ng/L were identified in waters sampled from
the German Weser estuary in 1977 . The concn of 2,6-dichlorophenol in a lake in Finland
receiving bleaching effluents from a pulping plant was 1.2 ppb .
GROUND WATER: 2,6- Dichlorophenol has been detected in the ground water profile
associated with a 2,4-D chemical waste disposal site in Alkali Lake, Oregon .
SEAWATER: The concn of 2,6-dichlorophenol in seawater collected from the Gulf of Bothnia
(Sweden) in Sept 1982 was found to range from 5 to 40 ng/l ; the sampling site was in the
vicinity of pulp mill effluent .
DRINKING WATER: In an analysis of water samples from 40 potable treatment plants in
Canada between Oct 1984 and July 1985, 2,6-dichlorophenol was detected in only one raw water
sample (4 ng/l); however, it was detected in 5 treated water samples at levels as high as 33
ng/l . A 2,6-dichlorophenol concn of 0.033 ppb was identified in tap water from Seoul, S Korea
in 1979 .
RAIN/SNOW: The dissolved concn of 2,6-dichlorophenol in rainwater from Portland, OR
during seven rain events between Feb and Apr 1984 varied from not detectable to 2.5 ng/l .
EFFL: Biologically treated effluent samples from nine Canadian bleached softwood Kraft mills
were analyzed for chlorinated phenolic content. Chlorinated phenolics, incl 2,6-dichlorophenol,
present in effluent discharged from bleached Kraft mills are not expected to contribute an off-odor
to recipient waters.
2,6-Dichlorophenol levels of 6-272 ng/l were detected in wastewaters from bleaching processes
at pulp mills . Combustion ash from a municipal incinerator was found to contain a
2,6-dichlorophenol level of 39 ppb . 2,6-Dichlorophenol was identified in the effluents from a
hazardous waste incinerator . A wastewater effluent from the electronics industry has been
reported to contain 2,6-dichlorophenol .
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