2,6-Dimethylpyridin

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.

3.1 [ppm]

34 [ppm]

200 [ppm]

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 200(SRC), determined from a measured log Kow of 1.68(2) and a regression-derived equation(3), indicates that 2,6-lutidine is expected to have moderate mobility in soil(SRC). The pKa of 2,6-lutidine is 6.6(4), which indicates that 2,6-lutidine will partially exist in the protonated form in moist soils and cations adsorb to soil surfaces more strongly than neutral compounds(SRC). Volatilization of the neutral species of 2,6-lutidine from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 1.04X10-5 atm-cu m/mole(5), but the protonated form will not volatilize. The potential for volatilization of 2,6-lutidine from dry soil surfaces may exist based upon a vapor pressure of 5.65 mm Hg(6). 2,6-Lutidine biodegrades in soils under aerobic conditions(7). The half-life of 2,6-lutidine was approximately 1 month in an unpolluted surface soil under aerobic conditions with 100% degradation observed after 3 months(7) in a second, 2,6-lutadine was completely degraded in 32 days(8). Little degradation was observed under denitrifying and sulfate-reducing conditions(7).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 200(SRC), determined from a measured log Kow of 1.68 (2) and a regression-derived equation(3), indicates that 2,6-lutidine is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon a Henry's Law constant of 1.04X10-5 atm-cu m/mole(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 2 and 31 days, respectively(SRC). The pKa of 2,6-lutidine is 6.6(5), which indicates that 2,6-lutidine will partially exist in the protonated form in water and cations will not volatilize(SRC). According to a classification scheme(6), an estimated BCF of 4(SRC), from its log Kow(2) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). 2,6-Lutidine was shown to biodegrade under aerobic conditions in soil (especially polluted soil), but the rate of degradation was slower under anaerobic conditions(8); similar biodegradation in water is expected. 2,6-Lutidine was degraded approximately 30% over the course of a 35 day incubation period in column experiments using contaminated groundwater from a coal tar producing chemical facility as inoculum(9).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2,6-lutidine, which has a vapor pressure of 5.65 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 2,6-lutidine 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 6 days(SRC), calculated from its rate constant of 2.8X10-12 cu cm/molecule-sec at 25 °C (SRC) determined using a structure estimation method(3).

2,6-Lutidine was detected in oil shale retort water in Australia at a concn of 3 mg/l(1). Effluent from a municipal treatment plant in Hamilton, Ontario released 2,6-lutidine at a rate of 0.42 kg/day(2). Unspecified isomers of lutidine were detected in feedwater and permeate water from an abandoned creosote manufacturing plant in Pensacola, FL at concns of 2.48 and 0.032 mg/l, respectively(3).

The Koc of 2,6-lutidine is estimated as 200(SRC), using a measured log Kow of 1.68(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that 2,6-lutidine is expected to have moderate mobility in soil. The pKa of 2,6-lutidine is 6.6(4), which indicates that 2,6-lutidine will partially exist in the protonated form in moist soils and cations adsorb to soil surfaces more strongly than neutral compounds(SRC).

An initial concn of 214 ppm 2,6-lutidine incubated in a Fincastle silt loam, was degraded 19, 22.2, 29.5, 42.4, 57.9 and 100% after 1, 2, 4, 8, 16 and 32 days, respectively(1). Mixed cultures isolated from a polluted soil were shown to degrade 2,6-lutidine(2). The half-life of 2,6-lutidine was approximately 1 month in an unpolluted surface soil under aerobic conditions with 100% degradation observed after 3 months, while little degradation was observed under denitrifying and sulfate reducing conditions(3). The half-life was about 0.5 months in polluted surface and subsurface soils with 100% degradation observed after 1 month(3). 2,6-Lutidine was degraded approximately 30% during a 35 day incubation period in column experiments using contaminated groundwater from a coal tar producing chemical facility as inoculum(4). The half-life of 2,6-lutidine in polluted subsurface sediments was 6 days(4).

An estimated BCF of 4 was calculated for 2,6-lutidine(SRC), using a log Kow of 1.68(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 2,6-lutidine is 1.04X10-5 atm-cu m/mole(1). This Henry's Law constant indicates that 2,6-lutidine is expected to volatilize from water surfaces(2). 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)(2) is estimated as 2 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)(2) is estimated as 31 days(SRC). 2,6-Lutidine's Henry's Law constant(1) indicates that volatilization from moist soil surfaces may occur(SRC). The pKa of 2,6-lutidine is 6.6(3), which indicates that 2,6-lutidine will partially exist in the protonated form in water and moist soils and cations will not volatilize(SRC). 2,6-Lutidine may volatilize from dry soil surfaces(SRC) based on its vapor pressure of 5.65 mm Hg at 25 °C(4).

...LUTIDINES...CAUSE SYMPTOMS RESEMBLING THOSE OBSERVED WITH PYRIDINE. THESE ARE LARGELY NONSPECIFIC & INCLUDE WEAKNESS, ATAXIA, DIARRHEA, & UNCONSCIOUSNESS. ... MAJORITY OF DERIV...ARE PRIMARY IRRITANTS & PENETRATE INTACT GUINEA PIG SKIN READILY. ... CAUSE...INTENSE SKIN & EYE IRRITATION. /PYRIDINE DERIVATIVES/

INHALATION OF 7500 PPM CONCN VAPOR OF 2,6-LUTIDINE BY RATS CAUSED 100% MORTALITY IN 1.2 HR.

IN DOGS WITH A UREA LOAD, IV ADMIN OF 2,6-LUTIDINE MARKEDLY INCR URINE VOL & UREA CLEARANCE.

The rate constant for the vapor-phase reaction of 2,6-lutidine with photochemically-produced hydroxyl radicals has been estimated as 2.8X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 6 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The pKa of 2,6-lutidine is 6.6(2), which indicates that 2,6-lutidine will partially exist in the protonated form in the environment(SRC). Analogous 3,5-lutidine has a weak absorption band that extends into the environmental UV spectrum(3), which suggests that direct photolysis is not likely to occur for alkylated pyridines(SRC).