ABSTRACT
O CASRN: 1024-57-3; DOT: 2761; DOT label: Poison; molecular formula: C10H5Cl7O; FW: 389.32; RTECS: PB9450000 Physical state: Liquid Melting point (°C): 157-160 (Singh, 1969) 162.8 (Plato and Glasgow, 1969) Diffusivity in water (x 10-5 cm2/sec): 0.46 at 20 °C using method of Hayduk and Laudie (1974) Flash point (°C): Solid is noncombustible but materials used as carrier solvents (e.g., kerosene or similar hydrocarbons) are often flammable, rendering the mixture as a flammable or combustible mixture. Henry’s law constant (x 10-5 atm⋅m3/mol): 3.2 at 25 °C (gas stripping-GC, Warner et al., 1987) 2.11 at 25 °C (thermodynamic method-GC/UV spectrophotometry, Altschuh et al., 1999) 0.59 at 5 °C, 0.84 at 15 °C, 1.48 at 20 °C, 2.27 at 25 °C, 3.26 at 35 °C; in 3% NaCl solution: 2.07
at 5 °C, 4.93 at 15 °C, 7.70 at 25 °C, 9.28 at 35 °C (gas stripping-GC, Cetin et al., 2006) Bioconcentration factor, log BCF: 2.90 (B. subtilis, Grimes and Morrison, 1975) 4.16 (freshwater fish), 3.69 (fish, microcosm) (Garten and Trabalka, 1983) 3.37 freshwater clam (Corbicula manilensis) (Hartley and Johnston, 1983) Soil organic carbon/water partition coefficient, log Koc: 4.32 (Taichung soil: pH 6.8, % sand: 25, % silt: 40, % clay: 35) (Ding and Wu, 1995) Octanol/water partition coefficient, log Kow: 4.56 at 25 °C (shake flask-GSC, Noegrohati and Hammers, 1992) 5.40 (Travis and Arms, 1988) Solubility in water (µg/L): 350 at 25-29 °C (Park and Bruce, 1968) 275 at 25 °C (quoted, Warner et al., 1987)
Vapor pressure (x 10-6 mmHg): 2.6 at 20 °C (IARC, 1974) 300 at 30 °C (Nash, 1983) Environmental fate: Biological. In a model ecosystem containing plankton, Daphnia magna, mosquito larva (Culex pipiens quinquefasciatus), fish (Cambusia affinis), alga (Oedogonium cardiacum), and snail (Physa sp.), heptachlor epoxide degraded to hydroxychlordene epoxide (Lu et al., 1975). Using settled domestic wastewater inoculum, heptachlor epoxide (5 and 10 mg/L) did not degrade after 28 d of incubation at 25 °C (Tabak et al., 1981). This is consistent with the findings of Bowman et al. (1965). They reported that heptachlor epoxide was not significantly degraded in 7 air-dried soils that were incubated for 8 d. When heptachlor epoxide was incubated in a sandy loam soil at 28 °C, however, 1-hydroxychlordene formed at yields of 2.8, 5.8, and 12.0% after 4, 8, and 12 wk, respectively (Miles et al., 1971). Photolytic. Irradiation of heptachlor epoxide by a 450-W high-pressure mercury lamp gave two half-cage isomers, each containing a ketone functional group (Ivie et al., 1972). Benson et al. (1971) reported a degradation yield of 99% when an acetone solution containing heptachlor epoxide was photolyzed at >300 nm for 11 h. An identical degradation yield was achieved in only 60 min when the UV wavelength was reduced to >290 nm. Graham et al. (1973) reported that when solid heptachlor epoxide was exposed to July sunshine for 23.2 d, 59.3% degradation was achieved. In powdered form, however, only 5 d were required for complete degradation to occur. The products include a semicage ketone and an intermediate that may be converted to an enantiomeric semicage ketone. Chemical/Physical. Heptachlor epoxide will hydrolyze via nucleophilic attack at the epoxide moiety forming heptachlor diol which may undergo hydrolysis forming heptachlor triol and hydrogen chloride (Kollig, 1993). At influent concentrations of 1.0, 0.1, 0.01, and 0.001 mg/L, the GAC adsorption capacities were 1,038, 210, 41, and 8.3 mg/g, respectively (Dobbs and Cohen, 1980). Exposure limits: ACGIH TLV: TWA 0.05 mg/m3 (adopted). Toxicity: LC50 (96-h) for pink shrimp (Penaeus duorarum) 0.04 µg/L (Schimmel et al., 1976). Acute oral LD50 for rats is 47 mg/kg, mice 39 mg/kg (quoted, RTECS, 1985). Drinking water standard (final): MCLG: zero; MCL: 0.2 µg/L. In addition, a DWEL of 0.4 µg/L was recommended (U.S. EPA, 2000). Source: When heptachlor is ingested by dairy animals, it is metabolized to heptachlor epoxide, and stored in the fatty tissues. Heptachlor epoxide is present in the excreted milk and can be present in other dairy products (Meyer et al., 1960). Uses: Not known.
