Cyclododecane

The expired air of 62 non-smoking humans was examined for the presence of environmental pollutants and other chemical constituents(1); cyclododecane was detected in the expired air of all three subject groups (diabetic, pre-diabetic and control)(1).

EC50; Species: Daphnia pulex (Water flea, neaonate <24 hr old); Conditions: freshwater, static, 17 °C, hard water; Concentration: 21000 ug/L for 48 hr; Effect: intoxication, immobilization /> or =96% purity/

EC50; Species: Scenedesmus subspicatus (Algae); Concentration: >2.1 mg/L for 72 hr; Effect: No effects on biomass or growth rate were observed. The range of test concentrations was limited by the water solubility. /Conditions of bioassay not specified in source examined/

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 5,300(SRC), determined from a structure estimation method(2), indicates that cyclododecane is expected to be immobile(SRC). Volatilization of cyclododecane from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.54 atm-cu m/mole(SRC), using a fragment constant estimation method(3). However, adsorption to soil is expected to attenuate volatilization(SRC). Cyclododecane is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.9X10-2 mm Hg at 25 °C(SRC), determined from a fragment constant method(4). A 6% of theoretical BOD using activated sludge in the Japanese MITI test(5), suggests that biodegradation is not an important environmental fate process in soil(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 5,300(SRC), determined from a structure estimation method(2), indicates that cyclododecane is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 1.54 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 4 hours and 5 days, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 9 years if adsorption is considered(5). According to a classification scheme(6), a BCF range of 1,100-14,400(7) suggests that bioconcentration in aquatic organisms is very high, provided the compound is not metabolized by the organism(SRC). A 6% of theoretical BOD using activated sludge in the Japanese MITI test(7), suggests that biodegradation is not an important environmental fate process in water(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), cyclododecane, which has an estimated vapor pressure of 0.029 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase cyclododecane 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 23 hours(SRC), calculated from its rate constant of 1.7X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Cyclododecane does not contain chromophores that absorb at wavelengths >290 nm(4) and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

/AQUATIC SPECIES/ We have provided a hazard ranking for 19 classes of compounds representing many of the nearly 500 organic compounds identified by gas chromatography-mass spectrometry in lake trout (Salvelinus namaycush) and walleye (Stizostedion vitreum vitreum) from the Great Lakes and Lake St. Clair. We initially made a provisional hazard ranking based on available published and unpublished information on aquatic toxicity, bioaccumulation, occurrence and sources. Acute toxicity tests with Daphnia pulex at 17 °C in reconstituted hard water were performed with 30 compounds representative of the 19 classes that were highest in the provisional ranking. The resulting toxicity data, along with information on the compounds' occurrence in Great Lakes fish and their sources, were ranked and weighted and then used in calculating the revised hazard ranking. The 10 most hazardous classes, in descending order, are as follows (values shown are mean 48-hr EC50s, in ug/mL): arene halides (e.g., polychlorinated biphenyls, DDT), 0.0011; phthalate esters, 0.133; chlorinated camphenes (toxaphene), 0.0082; polyaromatic hydrocarbons (PAHs; e.g., dimethyl-naphthalene) and reduced derivatives, 1.01; chlorinated fused polycyclics (e.g., trans-nonachlor), 0.022; nitrogen-containing compounds (e.g., O-methylhydroxylamine), 1.35; alkyl halides (e.g., (bromomethyl)cyclohexene), 10.1; cyclic alkanes (e.g., cyclododecane), 20.9; silicon-containing compounds (e.g., dimethyldiethoxy silane), 1.25; and heterocyclic nitrogen compounds (e.g., nicotine), 2.48. We recommend that chronic bioassays be conducted with fish and invertebrates to determine the sublethal effects of the following classes of compounds, for which few toxicity data are available: PAHs, heterocyclic nitrogen compounds, other nitrogen-containing compounds, alkyl halides, cyclic alkanes and silicon-containing compounds. Information from these types of studies will aid researchers in determining the possible causal role these contaminants play in the decline and reproductive impairment of Great Lakes fish.

Using a structure estimation method based on molecular connectivity indices(1), the Koc of cyclododecane can be estimated to be 5,300(SRC). According to a classification scheme(2), this estimated Koc value suggests that cyclododecane is expected to be immobile in soil.

/SIGNS AND SYMPTOMS/ Cyclooctane and other volatile cycloalkanes are CNS depressants and have been identified as aspiration hazards.

/OTHER TOXICITY INFORMATION/ Cyclododecane is not a skin irritant.

A BCF range of 1,100-11,1000 and 1,800-14,400 was measured in fish for cyclododecane using a test chemical concentration of 30 and carp (Cyprinus carpio) which were exposed over an 10-week period(1). According to a classification scheme(2), these BCF values suggest the potential for bioconcentration in aquatic organisms is very high(SRC), provided the compound is not metabolized by the organism(SRC).

The Henry's Law constant for cyclododecane is estimated as 1.54 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that cyclododecane is expected to volatilize rapidly 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 4 hours(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 5 days(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 9 years if adsorption is considered. Cyclododecane's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). Cyclododecane is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 0.029 mm Hg(SRC), determined from a fragment constant method(4).