### TECHNICAL SUPPORT DOCUMENT:

BIOACCUMULATION AND PE RSISTENCE DATA FOR

SELECTED NITROARENES

6-Nitrochrysene (7496-02-8) 1,6-Dinitropyrene (42397-64-8) 1,8-Dinitropyrene (42397-65-9) 4-Nitropyrene (57835-92-4)

Office of Environmental Information Environmental Analysis Division Analytical Support Branch

November 20091 I. Introduction

This technical support document contai ns information on the bioaccumulation and persistence properties of four n itroarenes: 6-nitrochrysene (Che mical Abstracts Service Number (CAS No.) 7496-02-8); 1,6-di nitropyrene (CAS No. 42397-64-8) ; 1,8-dinitropyr ene (CAS No. 42397-65-9); and 4-nitropyrene (CAS No. 57835-92-4). Since there is little chemical specific persistence data for these nitroa renes, data on the persistence of 1-nitropyrene, a structural isomer of 4-nitropyrene and clos e chemical analog of the othe r nitroarenes, are presented.

Structures of all five nitr oarenes are presented below.

O 2 N NO 2 O 2 N NO 2

1-Nitropyrene 4-Nitropyrene 1,6-Dinitropyrene

NO 2 O 2 N NO 2

1,8-Dinitropyrene 6-Nitrochrysene

1-Nitropyrene is a member of the Emerge ncy Planning and Comm unity Right-to-Know Act (EPCRA) section 313 polycyclic aromatic compounds (PACs) category. The PACs category was designated as a category of persistent, bio accumulative, toxic (PBT ) chemicals in 1999 PBT chemical rule (October 29, 1999, 64 FR 58666). Data on the bioaccumulation and persistence properties of 1-nitropyrene were presented in th at rulemaking and associated support documents (January 5, 1999, 64 FR 688; USEPA/OPPT , 1998; Aronson, D. et.al., 1998).

II. Persistence Data

1-Nitropyrene – PBT Rule Data:

The persistence data presented in the PBT Chemical Rule (January 5, 1999, 64 FR 688) for 1-nitropyrene included half-lives for air and surface water. The half-life in air was reported as a range of 10 hours to 4 days. The technical report for the pers istence data (Aronson, D. et.al., 1998) included the following summary comments concerning this data:

“Based upon an estimated rate constant for the r eaction of 1-nitropyrene with hydroxyl radicals in the vapor phase (Kwok and Atkinson, 1995). Ho wever, this compound is expected to exist mainly in the particulate phase in the at mosphere [based on a vapor pressure of 5.52x10 -8 mm Hg (Neely and Blau, 1985)] which may re sult in longer half-lives. This compound is susceptible to2 direct photolysis as shown by seve ral laboratory studies using orga nic solvents (Fan et al. 1996; Holder et al., 1994; Koizumi et al., 1994).”

The half-lives in surface water were reported as a range of 16 to 44 years. The technical report for the persistence data (Aronson, D. et.al., 1998) included the following summary comments concerning this data:

“Half-lives given for the minera lization of 1-nitropyrene in tw o waters, an oil contaminated drainage pond (high t1⁄2) and a bay (low t1⁄2) (Heitk amp et al., 1991). Photolysis of 1-nitropyrene in surface waters may occur based on direct photolys is studies in organic solvents (Greenberg et al., 1987; Holloway et al., 1987; Koizumi et al., 1994); however, this compound is expected to adsorb to particulates and suspended material in the water and may be removed from the surface where photolysis will occur.”

No half-lives were presented for soil, but the technical report for the persistence data (Aronson, D. et.al., 1998) included the followi ng summary comments about soil half lives:

“No biodegradation studies were lo cated for this compound in soil. 1-Nitropyrene is expected to be resistant to aerobic biodegradation based on resu lts in water. Photolysis on the soil surface may occur based on laboratory results reported fo r 1-nitropyrene placed on glass surfaces and in organic solvents.”

6-Nitrochrysene, 1,6-Dinitropyrene, 1,8-Dinitropyrene and 4-Nitropyrene :

The analysis of the persistence of the four nitroarenes includes the previous data for 1- nitropyrene plus some additional information mainly addressing persistence in air.

1. Abiotic Degradation.

The polycyclic ring structures of the n itroarenes absorb ultraviolet light at environmentally relevant wavele ngths (greater than 290 nanometers (nm)) and are susceptible to direct photolysis in the atmosphere and in s un-lit waters (HSDB, 2009; Morel et al., 2006). Morel et al. (2006) observed major absorbance of ultraviolet light by 1,6- and 1,8-dinitropyrene at 245 nm, 284 nm, and also near 400 nm with a broad band characteris tic of nitroaromatics

Greenberg et al. (1987) measured about 70% decomposition of 1-nitropyrene, that was applied to a filter as a 0.1 milligrams per l iter (mg/mL) methanol solution and exposed to sunlight and air for 14 days. Benson et al. (1985) reported a half-life of 533 hours for the degradation of 1 micromole (μmo l) of 1-nitropyrene applied to a glass surface and exposed to natural sunlight for periods of 12 to 670 hours. 1-Nitropyrene at a concentr ation of 1 mg/mL in a benzene solution was degraded by 52.8% after 4 hours exposure to sunlight (Koizumi et al. 1994). Half-lives measured for 1-nitropyrene exposed to light ≥ 310 nm were 1.2 days in dimethyl sulfoxide (DMSO) at 0.5 mg/mL and 6 da ys on silica plates at 133 (parts per million (ppm) (Holloway et al., 1987). Half-lives m easured for 1,8-dinitropyrene following the same procedure were 0.7 days in DMSO and 5.7 days on silica plates. Morel et al. (2006) measured the photodegradation rates of 1,6- and 1,8- dinitropyrene in acetonitrile (4×10 -5 molar (M))3 saturated with N 2 , O 2 , or containing 5.6 M H 2 O and exposed to artificial light. Half lives derived from the reported first-order rate constants ranged from 24 to 46 minutes for 1,6-dinitropyrene and 1.2 to 1.8 hours for 1,8-dinitropyrene (Morel et al., 2006). Although th e actual wavelengths of light that caused this degrada tion were not specified, analysis of the products formed from this reaction indicated that the degradation took pl ace through an energy transition that requires absorbance of the higher, envir onmentally relevant wavelengths.

Most of the measured photolysis data repor ted above are for 1-nitropyrene. Although the behavior of this substance is expected to be representative of the photode gradation of the other 4- ring nitroarenes, slight differences in structure can result in differe nt rates of dir ect photolysis for these compounds (Morel et al., 2006). For exam ple, the rate of direct photolysis for 1,6- dinitropyrene in acetonitr ile saturated with N 2 and O 2 was four times greater than the rate of direct photolysis for 1,8-dinitropyrene measured under the same conditions (Morel et al., 2006). No photodegradation data were located fo r 6-nitrochrysene or 4-dinitropyrene.

The estimated rate constant for the reaction of 6-nitrochrysene and 4-nitropyrene with photochemically produced hydroxyl radicals in the atmosphere is approximately 6×10 -12 cubic meters (cm 3 )/molecule-second (sec) (U.S. EPA, 2008). This corresponds to a half-life of approximately 21 hours based on an atmosphe ric hydroxyl radical c oncentration of 1.5×10 6

molecules/cm 3 and a 12-hour day. The estimated rate constant for the reaction of 1,6- and 1,8- dinitropyrene with photochemically produced hy droxyl radicals in the atmosphere is approximately 5×10 -13 cm 3 /molecule-sec (U.S. EPA, 2008). This corresponds to a half-life of approximately 20 days based on an atmosphe ric hydroxyl radical c oncentration of 1.5×10 6

molecules/cm 3 and a 12-hour day. These values (21 hour s for 6-nitrochrysene and 4-nitropyrene, 20 days for 1,6- and 1,8-dinitropyrene) are some what higher than the range estimated for 1- nitropyrene which was 1 hour to 4 days (Aronson, D. et.al., 1998).

The rates of photolysis and photooxidation are e xpected to be slower for nitroarenes that are adsorbed onto carbonaceous atmospheric partic ulates (high elementa l carbon content) since the particulate matter can shield the adsorbed su bstance from incident light and attack from atmospheric radicals (Feilberg and Nielsen, 2000; Holder et al. 1994). Energy transfer from the adsorbed substance to the carbon surface may al so hinder photolysis (Feilberg and Nielsen, 2000). The composition of the partic ulate matter to which the nitroare ne is adsorbed is expected to influence the rate of phot odegradation. No photodegradati on was observed for 1-nitropyrene adsorbed to unfractionated coal fly ash or to the carbonaceous fraction of this ash after 24 hours irradiation using a xenon arc lamp (Holder et al. 1994). However, th e loss of 1-nitropyrene adsorbed to the ferromagnetic fraction, the mine ral fraction, and to si lica gel was 10-12%, 20- 21%, and 33-41%, respectively. Fa n et al. (1996) reported that the degradation of 1- and 2- nitropyrene adsorbed to wood smoke was more ra pid than the degradatio n of these substances adsorbed to diesel soot particulates when exposed to natural sunlight.

Hydrolysis is not expected to be an important removal mech anism for nitroarenes in the

environment since these structures do not contain functional groups that hydrolyze under environmental conditions (Lyman et al., 1990).4 2. Aerobic Biotic Degradation.

Very little biodegradation data are available for the nitroare nes. Heitkamp et al. (1991) reported that less than 1% of 1-nitropyrene a dded to estuarine sediments was converted to CO 2 after 8 weeks of aerobic incuba tion. These authors proposed th at the aerobic degradation pathway proceeded through the formation of the 1-nitropyrene cis-9,10- and 4,5-dihydrodiols followed by ring cleavage. Pothuluri et al . (1998) studied the aer obic metabolism of 6- nitrochrysene by the fungal species C. elegans and proposed a degradation pathway proceeding through the formation of 1- a nd 2-hydroxy-6-nitrochrysene follo wed by 6-nitrochrysene 1- and

2-sulfate.

Measured rate data for th e aerobic biodegradation of n itroarenes were not located. Biodegradation half-lives determined for the unsubstituted polycyclic aromatics chrysene and pyrene range from weeks to a few years (Aronson et al., 1999). Aerobi c biodegradation of the nitroarenes is expected to proceed even more slowly than that of the unsubstituted compounds since the presence of nitro groups on aromatic ri ngs makes these structures more resistant to aerobic biodegradation (Cerniglia and Somerville, 1995; Howard, 2000).

3. Anaerobic Biotic Degradation.

Heitkamp et al. (1991) reported that 0% of 1-nitropyrene, a structural isomer of 4- nitropyrene, added to estuarine sediments was converted to CO 2 after 8 weeks of anaerobic incubation. 1-Aminopyrene was detected as an anaerobic metabolite of 1-nitropyrene biodegradation during this proce ss, indicating that ni troarenes are reduced to form aromatic

amines under anaerobic conditions . The reduction of aromatic nitro groups under anaerobic conditions is well known (B oethling et al., 1995).

III. Bioaccumulation Data

As was done previously for 1-nitropyrene, a nd most of the other members of the PACs category, the bioconcentration factors (BCFs) fo r the four nitroarenes were calculated using estimated log K

ow values and a regression-derived equation (USEPA/OPPT, 1998). The estimated BCF value for 1-nitropyrene cited in the PBT rule was 908 (January 5, 1999, 64 FR 688, USEPA/OPPT, 1998). The re gression equation used to estimate the BCF value for 1- nitropyrene was:

Equation 1: log BCF = 0.77 log Kow - 0.70 + correction factor

The above equation is from version 2 of the SRC program (BCF WIN, the Bioconcentration Factor Estimation Program, version 2.0 (USEPA/O PPT, 1998)). The latest version of that program uses a revised equation (USEPA 2008):

Equation 2: Log BCF = 0.6598 log Kow - 0.333 + correction factor5 The results of the BCF estimations using both e quations are presented in the table below, no correction factors were used for either equation. The estimated log Kow values used to calculate

the BCF values are also liste d in the table (USEPA 2008).

Chemical Log Kow BCF equation 1 BCF equation 2

1,6-dinitropyrene 4.57 660 480 1,8-dinitropyrene 4.57 660 480 6-nitrochrysene 5.34 2600 1600 4-nitropyrene 4.75 910 630

IV. References

Aronson, D. et.al., (1998) Chemical Fate Half -Lives for Toxics Release Inventory (TRI) Chemicals. Prepared by Syracuse Research Corp . for Robert S. Boethling, USEPA Office of Pollution Prevention and Toxics, Washington, DC. July 30, 1998. SRC TR 98-008.

Aronson, D; Citra, M, Shuler, K; et al. (1999) Aerobic biodegrad ation of organic chemicals in environmental media: A summary of field a nd laboratory studies. Prepared for U.S. Environmental Protection Agency, Athens, GA.

Benson, J.M., Brooks, A.L., Cheng, Y.S., Henderson, T.R. and White, J.E. Environmental transformations of 1-nitropyrene on gla ss surfaces. Atmos. Environ. 19: 1169-1174. 1985.

Boethling, RS; Howard, PH; Beauman, JA; et al. ( 1995) Factors for intermedia extrapolation in biodegradability assessment. Chemosphere 30(4):741–752.

Cerniglia, CE; Somerville, CC. (1995) Reductive metabolism of nitroaromatic and nitropolycyclic aromatic hydrocarbons. In: Bi odegradation of nitroaromatic compounds. New York, NY: Plenum Press, 99–115.

Fan, Z., Kamens, R.M., Hu, J., Zhang, J. and McDo w, S. Photostability of nitro-polycyclic aromatic hydrocarbons on combustion soot particle s in sunlight. Environ. Sci. Technol. 30:

1358-1364. 1996.

Feilberg, A; Nielsen, T. (2000) E ffect of aerosol chemical composition on the photodegradation of nitro-polycyclic arom atic hydrocarbons. Envir on Sci Technol 34(5);789-797.

Greenberg, A., Darack, F., Wang, Y., Harkov, R., Louis, J. and Ather holt, T. Fate of airborne PAH and nitro-PAH. Proceedings of the 80t h Annual Meeting of the APCA. 6: 1-33. 1987.

Heitkamp, M.A., Freeman, J.P., Miller, D.W. and Cerniglia, C.E. Biodegradation of 1- nitropyrene. Arch. Microbiol. 156: 223-230. 1991.6 Holder, P.S., Wehry, E.L. and Mamantov, G. P hotochemistry transformation of 1-nitropyrene sorbed on coal fly ash fractions. Polycyclic Arom. Comp. 4: 135-139. 1994.

Holloway, M.P., Biaglow, M.C., McCoy, E.C., Ande rs, M., Rosenkranz, H.S. and Howard, P.C. Photochemical instability of 1- nitropyrene, 3-nitrofluoranth ene, 1,8-dinitropyrene and their parent polycyclic aromatic hydroc arbons. Mutat. Res. 187: 199-207. 1987.

Howard, PH. (2000) Biodegradation. In: Prope rty estimation methods for chemicals. Boca Raton, FL: Lewis Publishers, 281–310.

HSDB (Hazardous Substances Data Bank). (200 9) 1-Nitropyrene, chrysene, and pyrene. National Library of Medicine. Available onlin e at http://toxnet.nlm.nih.gov. (accessed July 24, 2009).

Koizumi, A., Satioh, N., Suzuki, T. and Kami yama, S. A novel com pound, 9-hydroxy-1-pyrene, is a major photodegraded compound of 1-nitropyrene in the environment. Arch. Environ. Health.

49: 87-93. 1994.

Kwok, E.S.C. and Atkinson, R. Estimation of hydr oxyl radical reaction rate constants for gasphase organic compounds using a st ructure-reactivity relationship: an update. Atmos. Environ.

29: 1685-1695. 1995.

Lyman, WJ; Reehl, WF; Rosenblatt, DH. (1990) Se lected nitroarenes. In: Handbook of chemical property estimation methods. Environmental beha vior of organic compounds. Washington, DC: American Chemical Society, 4-8; 7-4–7-5; 8-13; 15-15–15-17.

Morel, MC; Alers, I; Arce, R. (2006) Photochemical degradati on of 1,6-and 1,8-dinitropyrene in solution. Polycyclic Aromatic Compounds 26:207–219.

Neely, W.B. and Blau, G.E. Environmental e xposure from chemicals. Volume 1. Boca Raton,

FL: CRC Press. 1985.

Pothuluri, JV; Sutherland, JB ; Freeman, JP; et al. (1998) Fungal biotransformation of 6- Nitrochrysene. Appl Environ Microbiol 64:3106–3109

USEPA/OPPT. 1998. Technical Support Document for Determination of Bioaccumulation (BAF) and Bioconcentration (BCF) Values fo r Persistent Bioaccumulative Toxic (PBT)

Chemicals and for Identification of PBT Chemi cals. Jerry Smrchek, Ph.D., Biologist, Existing Chemicals Assessment Branch, Risk Assessment Division. September 1998.

USEPA 2008. Estimation Programs Interface Suite (EPI Suite) TM . Available online at http://www.epa.gov/oppt/exposure/pubs/eipsu itedl.htm. (accessed July 24, 2009).