Correspondence pubs.acs.org/journal/estlcu
Response to Correspondence on Identification and Toxicological Evaluation of Unsubstituted PAHs and Novel PAH Derivatives in Pavement Sealcoat Products We appreciate the interest from Magee and Forsberg1 from Arcadis (with funding from the Pavement Coatings Technology Council) in our recent publication.2 With regard to sample storage and transfer, the samples were collected from late 2009 to early 2010 by the U.S. Geological Survey (USGS)3 and stored in the dark below −4 °C in sealed amber glass jars by the USGS. In 2012, portions of the product and time point scrapes were shipped overnight to Oregon State University (OSU) in sealed amber glass vials, which were placed in two sealed airtight bags, inside a cooler containing ice. The samples were immediately placed inside a dark −20 °C freezer upon arrival at OSU. In 2014, the samples were warmed to room temperature in the sealed amber vials, just prior to extraction at OSU. Only four of the time point scrapes analyzed by the USGS were analyzed in our study (1.6 h, 1 day, 45 days, and 149 days), because the other time point scrapes had been completely used in the prior USGS analyses.3 With regard to the difference between our measured concentrations and Van Metre et al.’s measured concentrations3 for the 1.6 h and 1 day time point scrapes, we have rechecked our raw data and determined that the data reported in our study are correct. However, Magee and Forsberg’s comparison1 of the 1.6 h time point scrape between our study2 and that of Van Metre et al.3 is incorrect. As noted in Figure 1 of ref 3, the 1.6 h time point scrape in ref 3 is represented by the PAH concentration of the coal tar (CT) product, of which the concentrations are similar between the two studies (Figure S1)2. We reported the PAH concentration of the actual 1.6 h time point scrape. Our reported BaPeq-concentration for the 1 day time point scrape2 was a factor of 2.8 higher than that of Van Metre et al.3 Magee and Forsberg stated that we “... speculate that nitroPAHs (NPAHs) and oxygenated PAHs (OPAHs) formed through phototransformation of PAHs in the sealcoat”.1 We stated “... the increased concentrations of some NPAHs and OPAHs on the sealcoated surface over time may have originated, in part, from phototransformation of unsubstituted PAHs and MPAHs on the sealcoated suface”.2 It is common knowledge that PAH transformation products can result from phototransformation of parent PAHs on solid surfaces, including on atmospheric particulate matter (PM), silica, alumina, coal fly ash, and soil, as evidenced by prior publications.4−11 Magee and Forsberg suggested further testing to explain the increase in NPAHs and OPAHs concentrations over time.1 We welcome the pavement sealcoat industry to conduct this testing, as proposed by their consultants.1 It is important to note that we did not conduct a risk assessment of the pavement sealcoat products. Rather, we calculated the BaPeq-concentrations, following the most recent and available draft U.S. Environmental Protection Agency and Health Canada protocols.12,13 In the context of our manuscript and the calculation of BaPeq-concentration, Magee and © XXXX American Chemical Society
Forsberg’s statement regarding the bioavailability of MW302PAHs, relative to BaP, was misplaced. To reiterate our findings, in CT pavement sealcoat products, inclusion of the MW302PAH concentration in the BaPeq-concentration resulted in a 4.1−38.7% increase in BaPeq-concentration, while MW302PAHs were not detected in the asphalt (AS) pavement sealcoat product.2 We stated “... the presence of MW302-PAHs in the CT pavement sealcoat product, and their absence from the AS pavement sealcoat product, may make MW302-PAHs a unique molecular marker for CT pavement sealcoat product use in the urban environment where coal is no longer burned”.2 To clarify, we suggested that measurement of MW302-PAHs will help distinguish between CT and AS pavement sealcoat products. To date, MW302-PAHs have been primarily linked to use of coal-derived products, as well as coal combustion and waste,14−17 which results in the presence of MW302-PAHs throughout the environment. The sources of MW302-PAHs in the papers referenced by Magee and Forsberg can be primarily traced back to coal-related materials, including coal emissions and PM,18,19 industrial and power plants,20 and carbon black,21 and/or were sampled in cities where coal-fired power plants were still functioning at the time of sampling18−24 and/or where coal was transported.25 Of course, the sources of MW302-PAHs in environmental matrices, including atmospheric PM and sediment, may include coal-related materials, such as CT pavement sealcoat products. We welcome the pavement sealcoat industry to further investigate the concentrations of MW302-PAHs in CT and AS pavement sealcoat products, as well as in other possible sources in the environment, as suggested by their consultants.1 The published literature shows that the log Kow values of NPAHs and OPAHs are lower than the log Kow values of their corresponding parent PAHs.26−28 This suggests that NPAHs and OPAHs will be more bioavailable in the aquatic environment than their corresponding parent PAHs, as suggested by other authors.9,26,27,29−32 We tested the PAH-containing fractions of CT and AS pavement sealcoat extracts using both the Ames mutagenicity assay and the zebrafish developmental toxicity test to directly compare the CT and AS fractions. To date, there is no direct experimental evidence showing that pavement sealcoat products would have “... an antagonistic mutagenic response”.1 We welcome the pavement sealcoat industry to conduct this testing, as proposed by their consultants.1 We agree with Magee and Forsberg1 that both the CT and AS pavement sealcoat fractions we tested were toxic to zebrafish.2 Received: October 14, 2016 Accepted: October 17, 2016
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DOI: 10.1021/acs.estlett.6b00400 Environ. Sci. Technol. Lett. XXXX, XXX, XXX−XXX
Environmental Science & Technology Letters
Correspondence
Derivatives in Pavement Sealcoat Products. Environ. Sci. Technol. Lett. 2016, DOI: 10.1021/acs.estlett.6b00360. (2) Titaley, I. A.; Chlebowski, A.; Truong, L.; Tanguay, R. L.; Massey Simonich, S. L. Identification and Toxicological Evaluation of Unsubstituted PAHs and Novel PAH Derivatives in Pavement Sealcoat Products. Environ. Sci. Technol. Lett. 2016, 3, 234−242. (3) Van Metre, P. C.; Majewski, M. S.; Mahler, B. J.; Foreman, W. T.; Braun, C. L.; Wilson, J. T.; Burbank, T. L. PAH Volatilization Following Application of Coal-Tar-Based Pavement Sealant. Atmos. Environ. 2012, 51, 108−115. (4) Pagni, R. M.; Sigman, M. E. The Photochemistry of PAHs and PCBs in Water and on Solids. In Environmental Photochemistry; Boule, D. P., Ed.; The Handbook of Environmental Chemistry; Springer: Berlin, 1999; pp 139−179. (5) Wang, W.; Jariyasopit, N.; Schrlau, J.; Jia, Y.; Tao, S.; Yu, T.-W.; Dashwood, R. H.; Zhang, W.; Wang, X.; Simonich, S. L. M. Concentration and Photochemistry of PAHs, NPAHs, and OPAHs and Toxicity of PM2.5 during the Beijing Olympic Games. Environ. Sci. Technol. 2011, 45, 6887−6895. (6) Debestani, R.; Ellis, K. J.; Sigman, M. E. Photodecomposition of Anthracene on Dry Surfaces: Products and Mechanism. J. Photochem. Photobiol., A 1995, 86, 231−239. (7) Reyes, C. A.; Medina, M.; Crespo-Hernandez, C.; Cedeno, M. Z.; Arce, R.; Rosario, O.; Steffenson, D. M.; Ivanov, I. N.; Sigman, M. E.; Dabestani, R. Photochemistry of Pyrene on Unactivated and Activated Silica Surfaces. Environ. Sci. Technol. 2000, 34, 415−421. (8) Reyes, C.; Sigman, M. E.; Arce, R.; Barbas, J. T.; Dabestani, R. Photochemistry of Acenaphthene at a Silica Gel/Air Interface. J. Photochem. Photobiol., A 1998, 112, 277−283. (9) Yu, H. Environmental Carcinogenic Polycyclic Aromatic Hydrocarbons: Photochemistry and Phototoxicity. J. Environ. Sci. Health Part C Environ. Carcinog. Ecotoxicol. Rev. 2002, 20, 149−183. (10) Barbas, J. T.; E. Sigman, M.; Arce, R.; Dabestani, R. Spectroscopy and Photochemistry of Fluorene at a Silica Gel/Air Interface. J. Photochem. Photobiol., A 1997, 109, 229−236. (11) Dabestani, R.; Higgin, J.; Stephenson, D.; Ivanov, I. N.; Sigman, M. E. Photophysical and Photochemical Processes of 2-Methyl, 2Ethyl, and 2-tert-Butylanthracenes on Silica Gel. A Substituent Effect Study. J. Phys. Chem. B 2000, 104, 10235−10241. (12) Integrated Risk Information System. Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures: In Support of Summary Information on the Integrated Risk Information System (IRIS). RPA/635/R-08/012A; U.S. Environmental Protection Agency: Washington, DC, 2010 (http://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid= 194584) (accessed September 15, 2016). (13) Health Canada. Federal Contaminated Site Risk Assessment in Canada, part I: Guidance on Human Health Preliminary Quantitative Risk Assessment (PQRA), version 2.0; Contaminated Sites, Reports and Publications. H128-1/11-632E-PDF; Minister of Health, Government of Canada: Ottawa, ON, 2005 (http://publications.gc.ca/ collections/collection_2012/sc-hc/H128-1-11-632-eng.pdf) (accessed September 27, 2016). (14) Schubert, P.; Schantz, M. M.; Sander, L. C.; Wise, S. A. Determination of Polycyclic Aromatic Hydrocarbons with Molecular Weight 300 and 302 in Environmental-Matrix Standard Reference Materials by Gas Chromatography/Mass Spectrometry. Anal. Chem. 2003, 75, 234−246. (15) Fetzer, J. C.; Kershaw, J. R. Identification of Large Polycyclic Aromatic Hydrocarbons in a Coal Tar Pitch. Fuel 1995, 74, 1533− 1536. (16) Marvin, C. H.; Lundrigan, J. A.; McCarry, B. E.; Bryant, D. W. Determination and Genotoxicity of High Molecular Mass Polycyclic Aromatic Hydrocarbons Isolated from Coal-Tar-Contaminated Sediment. Environ. Toxicol. Chem. 1995, 14, 2059−2066. (17) Ledesma, E. B.; Kalish, M. A.; Nelson, P. F.; Wornat, M. J.; Mackie, J. C. Formation and Fate of PAH During the Pyrolysis and Fuel-Rich Combustion of Coal Primary Tar. Fuel 2000, 79, 1801− 1814.
Lastly, Magee and Forsberg were correct; we routinely remove the chorions from early life stage zebrafish for a number of practical reasons related to bioavailability and quality control and to achieve more consistent analysis. There is no evidence that the chorion would provide a barrier or shield for any of the PAHs under investigation in this study. The chorion pore sizes are approximately 0.5 μm, providing gaping holes for PAH to access the embryo.33 To avoid potential differences in adsorption of PAH to the chorions that could influence uptake and resulting readouts, we chose to remove them. This also allows a direct comparison between the activity profile of these PAHs with our growing database of chemical responses collected using this standard assay protocol.31,34−36 Experimentally, we have confirmed that zebrafish with intact chorions are highly sensitive to PAH exposures, displaying a full battery of toxic responses.37,38 Clearly, chorions are not effective barriers. Furthermore, because we prefer not to sanitize or bleach the eggs prior to toxicity assessments (as these chemical treatments influence chorion properties), removal of the chorion also ensures that the test system does not contain extraneous debris or biomass that could influence the results or data interpretation. Finally, the removal of the chorion facilitates visual toxicological assessments, improving data reproducibility. In summary, this study design is deliberately designed to yield the most consistent, high-quality hazard assessment information that supports comparative data analysis. Certainly, laboratory test systems utilizing glass or plastic vessels never reflect “real world” aquatic scenarios, but they represent a controlled experimental design that provides definitive and interpretable information.
Ivan A. Titaley† Anna Chlebowski‡ Lisa Truong‡ Robert L. Tanguay‡ Staci L. Massey Simonich*,†,‡ †
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Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States ‡ Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Phone: (541) 7379194. Fax: (541) 737-0497. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This publication was made possible in part by National Institute of Environmental Health Sciences (NIEHS) Grant P30ES00210, NIEHS Grant P42ES016465, the National Institutes of Health (NIH), and National Science Foundation Grant AGS-11411214. I.A.T. was supported in part through the OSU Department of Chemistry Dorothy and Ramons Barnes Fellowship and NIEHS Training Grant Fellowship T32 ES007060 from the NIH.
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REFERENCES
(1) Magee, B. H.; Forsberg, N. D. Correspondence on Identification and Toxicological Evaluation of Unsubstituted PAHs and Novel PAH B
DOI: 10.1021/acs.estlett.6b00400 Environ. Sci. Technol. Lett. XXXX, XXX, XXX−XXX
Environmental Science & Technology Letters
Correspondence
(18) Layshock, J.; Simonich, S. M.; Anderson, K. A. Effect of Dibenzopyrene Measurement on Assessing Air Quality in Beijing Air and Possible Implications for Human Health. J. Environ. Monit. 2010, 12, 2290−2298. (19) Wei, S.; Liu, M.; Huang, B.; Bi, X.; Sheng, G.; Fu, J. Polycyclic Aromatic Hydrocarbons with Molecular Weight 302 in PM2.5 at Two Industrial Sites in South China. J. Environ. Monit. 2011, 13, 2568− 2574. (20) Allen, J. O.; Durant, J. L.; Dookeran, N. M.; Taghizadeh, K.; Plummer, E. F.; Lafleur, A. L.; Sarofim, A. F.; Smith, K. A. Measurement of C24H14 Polycyclic Aromatic Hydrocarbons Associated with a Size-Segregated Urban Aerosol. Environ. Sci. Technol. 1998, 32, 1928−1932. (21) Sadiktsis, I.; Bergvall, C.; Johansson, C.; Westerholm, R. Automobile TiresA Potential Source of Highly Carcinogenic Dibenzopyrenes to the Environment. Environ. Sci. Technol. 2012, 46, 3326−3334. (22) Bergvall, C.; Westerholm, R. Identification and Determination of Highly Carcinogenic Dibenzopyrene Isomers in Air Particulate Samples from a Street Canyon, a Rooftop, and a Subway Station in Stockholm. Environ. Sci. Technol. 2007, 41, 731−737. (23) Certificate of Analysis for Standard Reference Material 1649b. Urban Dust. National Institute of Standards & Technology: Gaithersburg, MD, 2016. (24) Certificate of Analysis for Standard Reference Material® 1648a. Urban Particulate Matter. National Institute of Standards & Technology: Gaithersburg, MD, 2015. (25) Certificate of Analysis for Standard Reference Material® 1941b. Organics in Marine Sediment. National Institute of Standards & Technology: Gaithersburg, MD, 2015. (26) Lundstedt, S.; White, P. A.; Lemieux, C. L.; Lynes, K. D.; Lambert, I. B.; Ö berg, L.; Haglund, P.; Tysklind, M. Sources, Fate, and Toxic Hazards of Oxygenated Polycyclic Aromatic Hydrocarbons (PAHs) at PAH- Contaminated Sites. Ambio 2007, 36, 475−485. (27) Postigo, C.; Barceló, D. Synthetic Organic Compounds and their Transformation Products in Groundwater: Occurrence, Fate and Mitigation. Sci. Total Environ. 2015, 503−504, 32−47. (28) IPCS-INCHEM (International Program on Chemical Safety). Selected Nitro and Nitro-Oxy-Polycyclic Aromatic Hydrocarbons. Environmental Health Criteria (ECH) Monographs 229; World Health Organization: Geneva, 2003 (http://apps.who.int/iris/bitstream/ 10665/42537/1/WHO_EHC_229.pdf) (accessed September 28, 2016). (29) Meyer, S.; Cartellieri, S.; Steinhart, H. Simultaneous Determination of PAHs, Hetero-PAHs (N, S, O), and Their Degradation Products in Creosote-Contaminated Soils. Method Development, Validation, and Application to Hazardous Waste Sites. Anal. Chem. 1999, 71, 4023−4029. (30) Mallakin, A.; McConkey, B. J.; Miao, G.; McKibben, B.; Snieckus, V.; Dixon, D. G.; Greenberg, B. M. Impacts of Structural Photomodification on the Toxicity of Environmental Contaminants: Anthracene Photooxidation Products. Ecotoxicol. Environ. Saf. 1999, 43, 204−212. (31) Knecht, A. L.; Goodale, B. C.; Truong, L.; Simonich, M. T.; Swanson, A. J.; Matzke, M. M.; Anderson, K. A.; Waters, K. M.; Tanguay, R. L. Comparative Developmental Toxicity of Environmentally Relevant Oxygenated PAHs. Toxicol. Appl. Pharmacol. 2013, 271, 266−275. (32) Layshock, J. A.; Wilson, G.; Anderson, K. A. Ketone and Quinone-Substituted Polycyclic Aromatic Hydrocarbons in Mussel Tissue, Sediment, Urban Dust, and Diesel Particulate Matrices. Environ. Toxicol. Chem. 2010, 29, 2450−2460. (33) Rawson, D. M.; Zhang, T.; Kalicharan, D.; Jongebloed, W. L. Field Emission Scanning Electron Microscopy and Transmission Electron Microscopy Studies of the Chorion, Plasma Membrane and Syncytial Layers of the Gastrula-Stage Embryo of the Zebrafish Brachydanio rerio: A Consideration of the Structural and Functional Relationships with Respect to Cryoprotectant Penetration. Aquacult. Res. 2000, 31, 325−336.
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DOI: 10.1021/acs.estlett.6b00400 Environ. Sci. Technol. Lett. XXXX, XXX, XXX−XXX
