Bacillus Coagulans Environmental Fate & Ecotoxicity

Lactic acid's production and use as an acidulant, in cultured dairy products, in chemicals (salts, plasticizers, adhesives, pharmaceuticals), as a mordant in dyeing wool, in general-purpose food additive, in the manufacture of lactates, in dehairing, plumping, and decalcifying hides, and as a solvent may result in its release to the environment through various waste streams. Lactic acid is a principal metabolic intermediate in most living organisms and also occurs in sour milk, foods, and some higher plants. If released to air, a vapor pressure of 0.0813 mm Hg at 25 °C indicates lactic acid will exist solely as a vapor in the atmosphere. Vapor-phase lactic acid will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 2.7 days. Lactic acid does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight. If released to soil, lactic acid is expected to have very high mobility based upon experimental Koc values ranging from <0.08 to <20.9. The pKa of lactic acid is 3.86, indicating that this compound will exist partially to almost entirely as an anion in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 9.6X10-9 atm-cu m/mole. Lactic acid is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Utilizing the Japanese MITI test, 76% of the Theoretical BOD was reached in 2 weeks indicating that biodegradation is an important environmental fate process. If released into water, lactic acid is not expected to adsorb to suspended solids and sediment based upon the Koc values. Various screening tests have found lactic acid to biodegrade readily. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to lactic acid may occur through dermal contact with this compound at workplaces where lactic acid is produced or used. Monitoring data indicate that the general population may be exposed to lactic acid via ingestion of food and drinking water and dermal contact with consumer products containing lactic acid. (SRC)

TERRESTRIAL FATE: Based on a classification scheme(1), experimentally-derived Koc values ranging from <0.08 to <20.9(2,3), indicate that lactic acid is expected to have very high mobility in soil(SRC). The pKa of lactic acid is 3.86(4), indicating that this compound will exist partially to almost entirely as an anion in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(5). Volatilization of lactic acid from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 9.6X10-9 atm-cu m/mole(SRC), derived from its vapor pressure, 0.0813 mm Hg(6), and an assigned value for water solubility of 1.0X10+6 mg/L (miscible)(7). Lactic acid is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(6). A 76% of theoretical BOD using activated sludge in a 2-week Japanese MITI test indicates lactic acid is readily biodegradable(8) and suggests that biodegradation is an important environmental fate process in soil(SRC). Other screening tests have also found lactic acid to biodegrade readily(9-11)

AQUATIC FATE: Based on a classification scheme(1), experimentally-derived Koc values ranging from <0.08 to <20.9(2,3), indicate that lactic acid is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(4) based upon an estimated Henry's Law constant of 9.6X10-9 atm-cu m/mole(SRC), derived from its vapor pressure, 0.0813 mm Hg(5), and an assigned value for water solubility of 1.0X10+6 mg/L (miscible)(6). The pKa of lactic acid is 3.86(7), indicating that this compound will exist partially to almost entirely in the anion form in the environment(SRC). The anion form will not volatilize, but by analogy to the similar acetic acid(8), lactic acid is expected to have a measurable Henry's Law constant even when almost entirely ionized. According to a classification scheme(9), an estimated BCF of 3(SRC), from a log Kow of -0.72(10) and a regression-derived equation(11), suggests the potential for bioconcentration in aquatic organisms is low(SRC). A 76% of theoretical BOD using activated sludge in a 2-week Japanese MITI test indicates lactic acid is readily biodegradable(12) and suggests that biodegradation is an important environmental fate process in water(SRC). Other screening tests have also found lactic acid to biodegrade readily(13-15). Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions(4)

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), lactic acid, which has a vapor pressure of 0.0813 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase lactic acid 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 2.7 days(SRC), calculated from its rate constant of 5.9X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Lactic acid does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(4)

AEROBIC: Lactic acid reached 22% of its theoretical BOD in 5 days using a sewage inoculum(1). In a closed bottle screening test, lactic acid, present at 2 mg/L, reached 12, 67, and 88% of its theoretical BOD after 5, 15, and 30 days, respectively, using an activated sludge inoculum(2). Lactic acid reached 59% of its theoretical BOD in 5 days using a sludge inoculum and the Warburg screening test(3). Lactic acid, present at 500 mg/L, reached 27.5, 29.4, and 33.3% of its theoretical BOD in 6, 12, and 24 hours, respectively, using an activated sludge inoculum at 2500 mg/L(4). Lactic acid was found to be easily biodegradable by biological sewage treatment(5). Lactic acid, present at 100 mg/L, reached 76% of its theoretical BOD in 2 weeks using an activated sludge inoculum at 30 mg/L in the Japanese MITI test which classified the compound as readily biodegradable(6)

ANAEROBIC: Lactic acid was rapidly oxidized to carbon dioxide by sulfate-reducing bacteria in anaerobic salt marsh sediments with a rate of about 125 nmoles oxidized/g dry mud/hour(1). Lactic acid was found to be amenable to ultimate anaerobic biodegradation in industrial wastewater(2)

The rate constant for the vapor-phase reaction of lactic acid with photochemically-produced hydroxyl radicals has been estimated as 5.9X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 2.7 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the reaction of hydroxyl radicals in aqueous solutions at pH 1 is 4.8X10+8 L/mol-sec(2); this corresponds to an aquatic half-life of about 4.6 years at an aquatic concentration of 1X10-17 hydroxyl radicals per liter(3). Lactic acid is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(4). Laboratory studies found aqueous solutions of lactic acid to be very stable with an estimated shelf-life of 70 years(5). Lactic acid does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(4)

An estimated BCF of 3 was calculated for lactic acid(SRC), using a log Kow of -0.72(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)

Experimental Koc values for lactic acid on a clastic mud (3.5% organic carbon) and a lateritic muddy sand (1.3% organic carbon) were 5.7 and <0.08, respectively(1). Utilizing an HPLC method, the Koc of lactic acid (93% aqueous solution) on soil and sewage sludge at neutral pH and pH 2 was <20.9(2). According to a classification scheme(3), these Koc values suggest that lactic acid is expected to have very high mobility in soil. The pKa of lactic acid is 3.86(4), indicating that this compound will exist partially to almost entirely in anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(5)

The Henry's Law constant for lactic acid is estimated as 9.6X10-9 atm-cu m/mole(SRC) derived from its vapor pressure, 0.0813 mm Hg(1), and an assigned value for water solubility of 1.00X10+6 mg/L (miscible)(2). This Henry's Law constant indicates that lactic acid is expected to be essentially nonvolatile from water surfaces(3). Lactic acid's estimated Henry's Law constant indicates that volatilization from moist soil surfaces is not expected to occur(SRC). Lactic acid is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1)

Lactic acid occurs in sour milk as a result of lactic acid bacteria(1). It also is found in molasses due to partial conversion of sugars, in apples and other fruits, tomato juice, beer, wines, opium, ergot, foxglove, and several higher plants, especially during germination(1). Lactic acid is ubiquitous in nature and is a principal metabolic intermediate in most living organisms(2). It is a constituent in blood(2)

Lactic acid's production and use as an acidulant, in cultured dairy products, in chemicals (salts, plasticizers, adhesives, pharmaceuticals), as a mordant in dyeing wool, in general-purpose food additive, in the manufacture of lactates, in dehairing, plumping, and decalcifying hides, and as a solvent(1,2) may result in its release to the environment through various waste streams(SRC). Lactic acid may be formed in the ambient atmosphere as a result of photooxidation (OH radicals or ozone) of hydrocarbons(3)

According to the 2012 TSCA Inventory Update Reporting data, 7 reporting facilities estimate the number of persons reasonably likely to be exposed during the manufacturing, processing, or use of lactic acid in the United States may be as low as 10-24 workers and as high as 500-999 workers per plant; the data may be greatly underestimated due to confidential business information (CBI) or unknown values(1)

NIOSH (NOES Survey 1981-1983) has statistically estimated that 107,962 workers (63,436 of these are female) are potentially exposed to lactic acid in the US(1). Occupational exposure to lactic acid may occur through dermal contact with this compound at workplaces where lactic acid is produced or used(SRC). Monitoring data indicate that the general population may be exposed to lactic acid via ingestion of food and drinking water and dermal contact with consumer products containing lactic acid(SRC)

Lactic acid was found to be excreted by humans through urine at a rate of 40 mg/kg body weight/day and through sweat at 45-452 mg/100 mL(1)

LC50; Species: Moina micrura (Water Flea) length 0.09 mm and breadth 0.06 mm; Conditions: freshwater, renewal; Concentration: 329120 ug/L for 96 hr (95% confidence interval: 315810-342430 ug/L) /88% purity/

LC50; Species: Oreochromis mossambicus (Mozambique Tilapia) adult, male and female, weight 11.83 g; Conditions: freshwater, renewal; Concentration: 257730 ug/L for 96 hr (95% confidence interval: 210540-315810 ug/L) /88% purity/

LC50; Species: Branchiura sowerbyi (Oligochaete) weight 0.002 g, length 20 mm; Conditions: freshwater, renewal; Concentration: 50820 ug/L for 96 hr (95% confidence interval: 48400-53240 ug/L) /88% purity/

LC50; Species: Oncorhynchus sp (Trout); Concentration: 100 mg/L for 18 hr /Conditions of bioassay not specified in source examined/

DRINKING WATER: Lactic acid was qualitatively detected in grab samples of treated drinking water taken from waterworks during March to December 1976(1)

SEAWATER: Lactic acid was detected at concentrations of 0.2 (2 samples), 0.2-4.9 (4 samples), and 0.6-1.6 umol/L (2 samples) in Sheldt estuary water, Belgian coastal water of the North Sea, and English Channel open sea water, respectively, collected between July 1997 and July 1998(1)

Lactic acid was qualitatively detected in the effluent of kraft mills in Springfield, OR and Everett, WA(1). Lactic acid was found in source-separated organic household waste collected from Uppsala, Sweden in February 1995 at a concentration range of 0.28-0.71% fresh weight(2)

SEDIMENT: Sediments collected at a depth of 0-3 cm from Loch Eil, Scotland from three different sampling stations had lactic acid concentrations of 14.4, 21.4, and 27.2 ug/g dry weight sediment(1)

Lactic acid was detected as a flavoring constituent of Nigerian gari (a type of tapioca made from cassava (Manihot esculenta) tubers)(1). Lactic acid occurs in sour milk as a result of lactic acid bacteria(2). Lactic acid is also found in molasses due to partial conversion of sugars, in apples and other fruits, tomato juice, beer, wines, opium, ergot, foxglove, and several higher plants, especially during germination(2). Lactic acid is present in many foods both naturally or as a product of in situ microbial fermentation, as in sauerkraut, yogurt, buttermilk, sourdough breads, and many other fermented foods(3)

Lactic acid occurrence in plants(1)

ENVIRONMENTAL: The purpose of this study was to determine if breast milk composition changed significantly following exercise conducted at different intensities. Nine postpartum women exercised on a treadmill up to maximal oxygen uptake (100% of VO2max) on the first laboratory visit, for 30 minutes on two subsequent occasions (50% and 75% of VO2max) and also performed a nonexercise control session. Blood and breast milk were collected prior to exercise, immediately after exercise, and at 30, 60, and 90 minutes postexercise. Blood samples were analyzed for lactic acid (LA) while milk samples were analyzed for LA, pH, lipid, ammonium, and urea. Milk LA after the 100% intensity session was significantly elevated through 90 minutes postexercise, while there was no significant increase in milk LA at any collection time after the 50% or 75% intensity sessions. There were no significant differences in milk pH, lipid, ammonium, or urea measurements after any of the exercise sessions. These data show that unlike maximum intensity exercise, moderate intensity exercise does not increase breast milk LA content

ENVIRONMENTAL: The purpose of this study was to observe the infant acceptance of postexercise breast milk. Twenty-six lactating postpartum women exercised to maximum (maximum oxygen consumption = 35.1 +/- 9.2 [SD] mL min-1 kg-1) on a treadmill. Breast milk was collected via self-expression at rest before exercise and at 10 and 30 minutes postexercise and analyzed for lactic acid by enzymatic methods. Following exercise, infants were presented with their mothers' pre-exercise and postexercise milk in a double-blind design. The mother rated the infant's acceptance of the milk samples. There was a significant difference in acceptance of pre-exercise and postexercise milk as analyzed by analysis of variance. Maximal exercise resulted in a significant increase in lactic acid concentration in breast milk that may be high enough to affect the taste of the milk. The decreased acceptance of postexercise milk was associated with increased lactic acid concentration. Suggestions to circumvent the decreased acceptance are offered