Addition/Correction pubs.acs.org/est
Additions and Correction to Is Ongoing Sulfluramid Use in South America a Significant Source of Perfluorooctanesulfonate (PFOS)? Production Inventories, Environmental Fate, And Local Occurrence John Löfstedt Gilljam, Juliana Leonel,* Ian T. Cousins, and Jonathan P. Benskin* Environ. Sci. Technol. 2016, 50 (2), 653−659; DOI: 10.1021/acs.est.5b04544. The recent publication “National Implementation Plan Brazil: Stockholm Convention”1 (referred to herein as The MOE Report) prepared by The Brazilian Ministry of the Environment, contained information on the production and emission of Sulfluramid, a topic we also recently published on.2 A comparison of our data to that in The MOE Report reveals that, while overall perfluoroctanesulfonate (PFOS) emissions for 2011 and 2012 are consistent, the assumptions used to derive these estimates are not. The MOE Report also contained new information on the manufacture and use of PFOS in Brazil, which was not included in our publication. Here we highlight some of this new information, along with uncertainties in production estimates from both publications. This information is summarized into the following four points:
Quantities of manufactured Sulfluramid (and consequently PFOS emissions) in Brazil could be more accurately determined if the quantity of imported starting material (POSF) were known. Unfortunately, POSF imports cannot be determined since this product is imported under a generic customs code.1 According to MOE officials, a code specific to POSF is under development.3 Thus, for the purposes of estimating total POSF consumption during the manufacture of Sulfluramid, The MOE Report multiplies the quantity of active ingredient (EtFOSA) by a factor of 1.6,1 and considers this quantity as equivalent to PFOS. We assume that this conversion factor accounts for both the yield of EtFOSA from POSF and the conversion in molecular weight, but a description of how this factor was derived was not provided in The MOE Report. A presentation at a recent meeting on Sulfluramid organized by the Brazilian Ministry of the Environment indicated that the POSF used for making Sulfluramid is 90% pure, and that only 70% of it has the isomer (presumably linear4) necessary to produce Sulfluramid. These reported values could account for this 1.6-fold conversion factor considering that 1 mol of linear EtFOSA would be produced from 1/0.7/0.9 = 1.59 mol of POSF (90% purity and containing 70% linear isomer) assuming a 100% reaction yield. Consequently, this leads to similar estimates of PFOS emission as those reported in Gilljam et al., despite starting with much less EtFOSA. Notably, in The MOE Report this 1.6-fold conversion factor is applied not only to production, but also to imports, exports, and internal sales of Sulfluramid, suggesting that the starting material and/or unreacted residuals are contained in the baits themselves. Clearly, characterization of Sulfluramid-containing baits is required to improve these assumptions, along with more accurate estimates of the reaction yield and isomer composition of EtFOSA synthesized from POSF.
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(1) PFOS EMISSION ESTIMATES ARE CONSISTENT BETWEEN STUDIES BUT SULFLURAMID PRODUCTION ESTIMATES ARE NOT A comparison of 2011 and 2012 data from The MOE Report and Gilljam et al. is provided in Table 1. While estimates for total PFOS-equivalents from Sulfluramid production for these years are similar (average of ∼50.75 tonnes in the MOE Report versus 48.44 tonnes in Gilljam et al.2), the average quantity of N-ethyl perfluorooctane sulfonamide (EtFOSA) produced for these years is divergent (an average of ∼32.80 tonnes in The MOE Report versus 52.24 tonnes in Gilljam et al. for 2011 and 2012). The difference in total EtFOSA quantities arises because our article considered production of both technical (i.e., 95− 98%) and formulated (i.e., 0.3%) Sulfluramid, while The MOE Report considers production of technical product only. It remains unclear as to which assumption is correct: on the one hand, if all technical Sulfluramid manufactured in Brazil is sold internally to companies which then use it to produce and sell formulated Sulfluramid, then summing both production estimates (i.e., technical and formulated) would lead to double-counting. On the other hand, if a company imports perfluorooctanesulfonyl fluoride (POSF) for the sole purpose of producing formulated Sulfluramid, then this quantity should be considered separately from technical material. It is notable that for 2009 the quantity of EtFOSA used in formulated product exceeds the quantity of technical product, which is difficult to reconcile if technical product is required to manufacture formulated material. One possibility is that technical product leftover from other years was used.3 However, given that for all other years the quantity of technical product exceeds that of formulated material, we suspect that the peculiarity for 2009 is due to missing data. © 2016 American Chemical Society
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(2) A LARGER NUMBER OF COMPANIES MANUFACTURE SULFLURAMID-BASED PRODUCTS THAN PREVIOUSLY ESTIMATED We reported that 10 Sulfluramid-based pesticides for agricultural use were produced under Brazil’s use exemption for the leafcutter ants Atta spp. and Acromyrmex spp. These products were manufactured by seven companies. However, according to The MOE Report, there are an additional 69 Sulfluramid-based products intended for household use, produced by 31 companies. It was also noted that companies which have products registered for agricultural use also have Published: June 28, 2016 7930
DOI: 10.1021/acs.est.6b02351 Environ. Sci. Technol. 2016, 50, 7930−7933
Environmental Science & Technology
Addition/Correction
Table 1. Comparison of Results of Gilljam et al. To Production Inventories from The MOE Report; All Values Have Been Rounded to Two Decimal Places and Are Provided in Metric Tonnes (t) The MOE Report1 imports (t): production EtFOSA (t): sales EtFOSA (t): exportsa EtFOSA (t): Brazilian EtFOSA emissionsd (t): Brazilian PFOS Emissions (t):
Gilljam et al.2
2011
2012
2011
2012
0.82 35.12 30.73 2.06 33.88 54.21c
1.26 30.47 33.29 2.18 29.55 47.28c
0.84 54.24 (35.12 technical +19.12 formulated) 48.86 (30.73 technical +18.13 formulated) 2.09 52.99 50.17d
1.30 50.24 (30.47 technical +19.77 formulated) 51.87 (33.29 technical +18.58 formulated) 2.22 49.32 46.70d
The MOE Report had two estimates for exports: “Exports Companies” and “Exports Aliceweb”. It appears that only the latter export data (which were approximately double that of “Exports Companies”) were used in the final PFOS use estimates, thus these values are included here. bBrazilian EtFOSA emissions = production + import − export. cEtFOSA emissions in The MOE Report are converted to POSF by multiplying by a factor of 1.6. POSF emissions are considered equivalent to PFOS emissions. dAssuming 100% conversion of EtFOSA to PFOS; molecular weight (MW) POSF = 502.12 g/mol, MW PFOS = 499.12 g/mol.
a
Table 2. Original Production and Emissions Estimates Provided in Gilljam et al. 2016 considering Both Technical and Formulated Product; All Values Have Been Rounded to Two Decimal Places and Are Provided in Metric Tonnes (t)
year 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
technical sulfluramid production (t EtFOSA)
formulated sulfluramid production (t EtFOSA)
total sulfluramid production (t EtFOSA)
sulfluramid production assumptions (t EtFOSA)
30.00 30.00 30.00 30.00 30.00 7.18 30.67 35.12 30.47 39.56
15.49 20.64 19.12 19.77 20.10
22.67 51.31 54.24 50.24 59.66 59.66 59.66
total EtFOSA (t): PFOS emissions (100% conversion) (t): PFOS/FOSA emissions (assuming 30.3% conversion to FOSA, 4% conversion to PFOS) (t):
imported sulfluramid (t EtFOSA)
import+production of sulfluramid (t EtFOSA)
exports of sulfluramid EtFOSA (t EtFOSA)
0.03 0.96 0.99 0.00 0.63 0.26 0.85 1.30 1.00 0.57 0.14
30.00 30.03 30.96 30.99 30.00 23.30 51.57 55.09 51.54 60.66 60.23 59.80
0.28 0.82 1.05 1.69 1.86 1.15 1.80 2.09 2.22 1.49 1.82 0.61
514.17 486.78 166.97
16.88 15.98 5.48
historical use of POSF-based products including in stain protection for papers and textiles, surfactants, and aqueous film forming foam (AFFF). Although there has been a phase-out of these products, they are probably still being released from ongoing use and waste streams. Emissions associated with these substances are highly uncertain and have thus not been estimated.
products registered for domestic use. These domestic products include pastes to control termites, paste to control cockroaches, and paste and granulated bait to control household ants. These products do not comply with the exemptions listed in the Stockholm Convention and as of January 8th, 2015, the Brazilian Health Surveillance Agency (Anvisa), set a period of 1 year for companies to sell their stocks and remove products from the Brazilian market (Anvisa Resolution, RE No. 41).1 Notably, at the time of preparing this manuscript, Sulfluramid could still be purchased at local markets throughout Bahia State, Brazil.
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(3) SULFLURAMID IS NOT THE ONLY SOURCE OF PFOS IN BRAZIL In Gilljam et al.2 we mentioned the possibility that lithium PFOS was also produced, but production data were not available at the time of publication. The MOE Report indicates that Bayowet FT 248 R (a product that contains PFOS) is imported from Germany for use in the metal plating industry. The average amount of PFOS estimated from the companies that use Bayowet FT 248 was ∼1.88 tonnes/year for 2011 and 2012.2 There are likely other sources of PFOS in Brazil from
We were pleased to see an Action Plan for PFOS-related products in The MOE Report, which prioritized investigations into the use of PFOS-related products in insecticides and in metal plating. Furthermore, the phase-out of domestic ant baits (which were in violation of Brazil’s use exemption from the Stockholm Convention1) is indeed a positive step toward reducing exposure to humans and wildlife. However, the report pointed out that substitutes to Sulfluramid for combatting Atta spp. and Acromyrmex spp. have not yet been identified. Thus, it appears that the use of Sulfluramid for agricultural purposes in
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(4) THE BRAZILIAN GOVERNMENT IS TAKING INITIATIVES TO PHASE-OUT AND/OR FIND ALTERNATIVES TO PFOS-RELATED PRODUCTS
DOI: 10.1021/acs.est.6b02351 Environ. Sci. Technol. 2016, 50, 7930−7933
Environmental Science & Technology
Addition/Correction
Table 3. Alternate Scenario 1: Production and Emissions Estimates Using Only Technical Sulfluramid Inventories; All Values Have Been Rounded to Two Decimal Places and Are Provided in Metric Tonnes (t) year 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
sulfluramid production (t EtFOSA)
sulfluramid production assumptions (t EtFOSA)
imported sulfluramid (t EtFOSA)
import+production of sulfluramid (t EtFOSA)
exports of sulfluramid (t EtFOSA)
0.03 0.96 0.99 0.00 0.63 0.26 0.85 1.30 1.00 0.57 0.14
30.00 30.03 30.96 30.99 30.00 7.81 30.93 35.97 31.77 40.56 40.13 39.70
0.28 0.82 1.05 1.69 1.86 1.15 1.80 2.09 2.22 1.49 1.82 0.61
378.85 358.67 123.02
16.88 15.98 5.48
30.00 30.00 30.00 30.00 30.00 7.18 30.67 35.12 30.47 39.56 39.56 39.56
total EtFOSA (t): total PFOS (t) from sulfluramid (2004−2015)a: total PFOS/FOSA (t) assuming partial conversionb: a
Assumes 100% conversion. bAssumes 30.3% conversion to FOSA and 4% conversion PFOS.
Brazil and elsewhere in Latin America will continue indefinitely for some time.
Table 4. Alternate Scenario 2: Production and Emission Estimates Using Technical Sulfluramid Inventories and assumptions from The MOE Report; All Values Have Been Rounded to Two Decimal Places and Are Provided in Metric Tonnes (t)
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HOW MUCH PFOS IS EMITTED FROM BRAZIL? Considering the updated information and assumptions provided in The MOE Report, we present here two new scenarios for the production and emission of EtFOSA and PFOS in Brazil. These new estimates assume that formulated product is produced from technical material; consequently, only technical material is considered for emissions estimates. For comparative purposes, the original estimates from Gilljam et al. are reproduced in Table 2, which assume that EtFOSA used in technical and formulated products is considered separately and then summed, resulting in a total of 514 tonnes of EtFOSA produced or imported from 2004 to 2015, with a corresponding release of 167−487 tonnes PFOS, depending on the yield.2 Alternate Scenario 1 (Table 3) assumes that technical product is used to manufacture formulated baits (as per The MOE Report); therefore, only technical product is considered in emissions estimates. Using this assumption, the total quantity of EtFOSA produced from 2004 to 2015 is ∼378.85 tonnes. Depending on the percentage yield (34.3− 100%), the quantity of PFOS emitted in Alternate Scenario 1 ranges from 123 to 359 tonnes (Table 3). Gilljam et al. and Alternate Scenario 1 assume that emissions are only from EtFOSA in the baits (i.e., POSF starting material is not considered, nor is PFOS used in metal plating). Alternate Scenario 1 estimates are lower than Gilljam et al. due to a lower estimated production of EtFOSA. Alternate scenario 2 (Table 4) again considers only technical material (as per Alternate Scenario 1), but applies the 1.6-fold conversion factor used in The MOE Report across all years from 2004 to 2015 to estimate PFOS emissions. It also includes 22.51 tonnes of PFOS used for metal plating, calculated using an annual import of ∼1.88 tonnes PFOS/yr between 2004 and 2015, based on The MOE Report estimates for 2011 and 2012. Using these assumptions, total PFOS emissions are estimated to be approximately 625 tonnes (27 of which are exported).
year
import+production of sulfluramid (t EtFOSA)
POSF equivalents production (t)a
POSF equivalents export (t)a
2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
30.00 30.03 30.96 30.99 30.00 7.81 30.93 35.97 31.77 40.56 40.13 39.70
48.00 48.05 49.53 49.58 48.00 12.49 49.49 57.54 50.83 64.90 64.21 63.53
0.45 1.31 1.67 2.71 2.97 1.84 2.89 3.34 3.54 2.39 2.91 0.97
606
27.0
603
26.8
total POSF (t) from sulfluramid (2004−2015): total PFOS (t) from sulfluramid (2004−2015)b: total PFOS (t) from metal plating (2004−2015)c: total PFOS (t) from sulfluramid and metal plating (2004−2015):
22.51 625
Using assumptions in The MOE Report (i.e., POSF = 1.6 × EtFOSA). MW POSF = 502.12 g/mol, MW PFOS = 499.12 g/mol. cAssumes 1.876 tonnes PFOS/yr for metal plating from 2004 to 2015 based on estimates from The MOE Report for 2011 and 2012.1 a b
Clearly, each of the aforementioned scenarios contains uncertainties, owing to considerable data gaps in Sulfluramid inventories in this region. In order to improve production and emissions estimates, better approximations of the imported quantities of POSF are needed, along with characterization of 7932
DOI: 10.1021/acs.est.6b02351 Environ. Sci. Technol. 2016, 50, 7930−7933
Environmental Science & Technology
Addition/Correction
commercial baits and the yield of PFOS produced from EtFOSA once it is applied in the environment. Until then, these data provide a first estimate of PFOS emissions arising from Sulfluramid in South America, for inclusion in Global PFOS emissions estimates.
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REFERENCES
(1) National implementation plan Brazil: Convention Stockholm/ ́ MMA: 2015; p 178. Ministry of the Environment. Brasilia. (2) Gilljam, J. L.; Leonel, J.; Cousins, I. T.; Benskin, J. P. Is ongoing Sulfluramid use in South America a significant source of perfluorooctane sulfonate (PFOS)? Production inventories, environmental fate, and local occurrence. Environ. Sci. Technol. 2016, 50, 653−659. (3) Ministry of the Environment, 2016. Seminar on the Viability of Alternative Products for Sulfluramid Use in the Control of Leaf-Cutting Ants Atta and Acromyrmex, March 15−16th, Brasilia, DF, Brazil. (4) Benskin, J. P.; De Silva, A. O.; Martin, J. W. Isomer profiling of perfluorinated substances as a tool for source tracking: A review of early findings and future applications. Rev. Environ. Contam. Toxicol. 2010, 208, 111−160.
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DOI: 10.1021/acs.est.6b02351 Environ. Sci. Technol. 2016, 50, 7930−7933
