2,4,6-Trimethylpyridin

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

1.3 [ppm]

14 [ppm]

85 [ppm]

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 250(SRC), determined from a log Kow of 1.9(2) and a regression-derived equation(3), indicates that 2,4,6-trimethylpyridine is expected to have moderate mobility in soil(SRC). The pKa of 2,4,6-trimethylpyridine is 7.4(4), indicating that this compound will mainly exist in the protonated form in the environment and cations generally adsorb to organic carbon and clay more strongly than their neutral counterparts, thus attenuating soil mobility(5). Volatilization of 2,4,6-trimethylpyridine from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 8.8X10-6 atm-cu m/mole(SRC), derived from its vapor pressure, 2.0 mm Hg(6), and water solubility, 3.5X10+4 mg/l(7). However, adsorption to soil is expected to attenuate volatilization(SRC). The potential for volatilization of 2,4,6-trimethylpyridine from dry soil surfaces may exist(SRC) based upon a vapor pressure of 2.0 mm Hg(6). Under aerobic and anaerobic conditions, 2,4,6-trimethylpyridine, present at 1 mM, degraded 100% in >97 days at pH 7 using a 0.5% garden soil suspension with glucose-yeast extract (20 ppm) and a screening test(8). Within 2 weeks under aerobic conditions, 100% transformation of 2,4,6-trimethylpyridine occurred in soil previously contaminated with pyridine contaminants(9).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 250(SRC), determined from a log Kow of 1.9(2) and a regression-derived equation(3), indicates that 2,4,6-trimethylpyridine is expected to adsorb slightly to suspended solids and sediment(SRC). However, the pKa of 2,4,6-trimethylpyridine is 7.4(4), indicating that this compound will mainly exist in the protonated form in the environment and cations generally adsorb to organic carbon and clay more strongly than their neutral counterparts(5). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 8.8X10-6 atm-cu m/mole(SRC), derived from its vapor pressure, 2.0 mm Hg(6), and water solubility, 3.5x10+4 mg/l(7). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 3.1 and 38 days, respectively(SRC). According to a classification scheme(8), an estimated BCF of 6(SRC), from its log Kow(2) and a regression-derived equation(9), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Under aerobic and anaerobic conditions, 2,4,6-trimethylpyridine, present at 1 mM, degraded 100% in >97 days at pH 7 using a 0.5% garden soil suspension with glucose-yeast extract (20 ppm) and a screening test(10).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2,4,6-trimethylpyridine, which has a vapor pressure of 2.0 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere(SRC). Vapor-phase 2,4,6-trimethylpyridine is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 2.3 days(SRC), calculated from its rate constant of 7.0X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3).

The concn of 2,4,6-trimethylpyridine in Australian oil shale retort water (basic fraction) was 2 mg/l(1). The concn of 2,4,6-trimethylpyridine in condensate and process retort water produced in modified in situ oil-shale retort were 70.1 and 4.0 mg/l, respectively(2). In a closed system, 2,4,6-trimethylpyridine was detected in air above 1 of 3 samples of shale oil wastewaters (detection limit of 0.4 ng per 1 ml air)(3); a concn of 8.3 ng of 2,4,6-trimethylpyridine per 1 ml of air was measured above a 1 ml sample of wastewater with a concn of <0.8 ng/ml of 2,4,6-trimethylpyridine(3).

The Koc of 2,4,6-trimethylpyridine is estimated as 250(SRC), using a log Kow of 1.9(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that 2,4,6-collidine is expected to have moderate mobility in soil(SRC). The pKa of 2,4,6-trimethylpyridine is 7.4(4), indicating that this compound will partially exist in the protonated form in the environment and cations generally adsorb to organic carbon and clay more strongly than their neutral counterparts(5).

MAJOR ACTIONS OF PYRIDINE & ITS SIMPLE ALKYL DERIV ARE...NERVOUS SYSTEM DEPRESSION... /PYRIDINE & ITS ALKYL DERIV/

...PYRIDINE AND ITS DERIV CAUSE LOCAL IRRITATION ON CONTACT WITH SKIN, MUCOUS MEMBRANES AND CORNEA. /PYRIDINE & DERIVATIVES/

TRANSIENT SYMPTOMS OF NAUSEA, HEADACHE, INSOMNIA, NERVOUSNESS, & LOW BACK OR ABDOMINAL DISCOMFORT WITH URINARY FREQUENCY HAVE BEEN OBSERVED IN PERSONS WITH REPEATED EXPOSURES TO PYRIDINE IN CONCN VARYING FROM 15-330 PPM. /PYRIDINE/

...EXPOSURE TO...MIXT OF PYRIDINE, PICOLINE, LUTIDINE, & COLLIDINE...IN 2 MEN. BOTH HAD GI DISTURBANCES, & 1 HAD...LOSSES OF CONSCIOUSNESS...FACIAL PARALYSIS, ANISOCORIA, & ATAXIA. OTHER HAD HEADACHE... RIGHT-SIDE FACIAL PARALYSIS, & 2 DAYS LATER...PTOSIS...ANISOCORIA, & LEFT-SIDED ABDUCENS PARESIS.

...COLLIDINES, CAUSE SYMPTOMS RESEMBLING THOSE OBSERVED WITH PYRIDINE. THESE ARE LARGELY, NONSPECIFIC & INCL WEAKNESS, ATAXIA, DIARRHEA, & UNCONSCIOUSNESS. DELAYED DEATHS FOLLOWING SINGLE DOSE ARE UNCOMMON & SURVIVORS GENERALLY GAIN WT NORMALLY. /COLLIDINES/

AEROBIC: 2,4,6-Trimethylpyridine, present at 1 mM, degraded 100% in >97 days at pH 7 using a 0.5% garden soil suspension with glucose-yeast extract (20 ppm) and a screening test(1). Within 2 weeks, 100% transformation of 2,4,6-trimethylpyridine occurred in soil previously contaminated with pyridine contaminants(2).

ANAEROBIC: 2,4,6-Trimethylpyridine, present at 1 mM, degraded 100% in >97 days at pH 7 using a 0.5% garden soil suspension with glucose-yeast extract (20 ppm) and a screening test(1).

An estimated BCF of 6 was calculated for 2,4,6-trimethylpyridine(SRC), using a log Kow of 1.9(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for 2,4,6-trimethylpyridine is estimated as 8.8X10-6 atm-cu m/mole(SRC) derived from its vapor pressure, 2 mm Hg(1), and water solubility, 3.5X10+4 mg/l(2). This Henry's Law constant indicates that 2,4,6-trimethylpyridine is expected to volatilize from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 3.1 days(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 38 days(SRC). 2,4,6-Trimethylpyridine's estimated Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). However, the pKa of 2,4,6-trimethylpyridine is 7.4(4) which suggests that volatilization from water surfaces is expected to be attenuated slightly since ions are not expected to volatilize(SRC). 2,4,6-Trimethylpyridine is expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

THE AMINO DERIVATIVES, THE 2- & 4-VINYL DERIVATIVES, & COLLIDINE APPEAR TO BE THE MOST POTENT PRIMARY IRRITANTS OF THE /PYRIDINE/ SERIES.

...RANGE-FINDING STUDIES... /TABLE:/ APPROX LD50 (G/KG) RATS ORAL 0.4; IP 0.05-0.1. MICE ORAL 0.2-0.4; IP 0.1-0.2. APPROX LD50 (ML/KG) GUINEA PIGS PERCUTANEOUS 1.0-2.0. WHERE RANGE IS GIVEN, ALL ANIMALS DIED AT HIGH DOSE & ALL SURVIVED AT LOWER DOSE. WHERE SINGLE FIGURE IS GIVEN, APPROX 1/2 THE ANIMALS DIED AT THAT DOSE.

THREE OF THREE RATS DIED FOLLOWING EXPOSURE TO 2500 PPM FOR 2 HR. CONCENTRATED VAPOR PRODUCED BY BUBBLING AIR THROUGH COMPD AT ROOM TEMP. /FROM TABLE/

The rate constant for the vapor-phase reaction of 2,4,6-trimethylpyridine with photochemically-produced hydroxyl radicals has been estimated as 7.0X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 2.3 hrs at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 2,4,6-Trimethylpyridine is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2). 3,5-Lutidine, a structurally similar alkylated pyridine, has a weak absorption band that extends into the environmental UV spectrum(3), which suggests that direct photolysis is not likely to be an important fate process for alkylated pyridines(SRC).