January 30, 2007 CERTIFIED MAIL RETURN RECEIPT REQUESTED

Transcription

1 New York State Department of Environmental Conservation Division of Solid and Hazardous Materials Bureau of Pesticides Management, 11th Floor 625 Broadway, Albany, New York Phone: (518) FAX: (518) Website: CERTIFIED MAIL RETURN RECEIPT REQUESTED Ms. Tann Schafer Manager, State Regulatory Affairs Monsanto Company 800 North Lindbergh Blvd. St. Louis, Missouri Dear Ms. Schafer: January 30, 2007 Re: Registration of the New Pesticide Products, Outrider Herbicide (EPA Reg. No ), and Certainty Turf Herbicide (EPA Reg. No ), Both of Which Contain the New Active Ingredient: Sulfosulfuron (Chemical Code ) The New York State Department of Environmental Conservation (Department) has reviewed your application, received February 9, 2006, to register the new pesticide products Outrider Herbicide (EPA Reg. No ) and Certainty Turf Herbicide (EPA Reg. No ) in New York State. These products have identical formulations and contain the new active ingredient sulfosulfuron (1-(2-ethylsulfonylimidazol [1,2-a] pyridin-3-yl-sulfonyl)-3-(4,6-dimethoxy-2- pyrimidinyl) urea). Outrider Herbicide is labeled for general weed control on non-crop sites including roadsides, utility rights-of-way, airports, ditch banks, railroads, industrial sites and warehouse areas. Certainty Turf Herbicide is labeled for general weed control on commercial and residential turf and other non-crop sites including cemeteries and golf courses. Toxicological Risk Assessment: The New York State Department of Health (DOH) reviewed the information submitted by Monsanto Company to register Outrider Herbicide and Certainty Turf Herbicide and found that neither the active ingredient sulfosulfuron nor the formulated products, Outrider Herbicide and Certainty Turf Herbicide, were very toxic in acute oral, dermal or inhalation toxicity studies in laboratory animals. Also, neither the active ingredient nor the formulated products were very irritating to the skin (tested on rabbits) nor were they skin sensitizers (tested on guinea pigs). All three materials, however, caused moderate eye irritation (tested on rabbits). In chronic rodent feeding studies, sulfosulfuron caused urinary tract lesions (both gross and microscopic) accompanied by urinary calculi formation in mice and rats at doses of about 394 and 244 milligrams per kilogram body weight per day (mg/kg/day), respectively. The respective noobserved-effect levels (NOELs) were 93.4 and 24.4 mg/kg/day. In a chronic dog feeding study,

2 Ms. Tann Schafer 2. urinary bladder pathology in conjunction with urinary tract calculi were observed in males at a dose of 500 mg/kg/day with a NOEL of 100 mg/kg/day. The United States Environmental Protection Agency (USEPA) calculated an oral reference dose (RfD) for sulfosulfuron of 0.24 mg/kg/day based on the NOEL from the rat chronic feeding study and an uncertainty factor of 100. This value has not yet been adopted by the USEPA s Integrated Risk Information System (IRIS). Sulfosulfuron did not cause developmental toxicity in the offspring of pregnant rabbits or rats administered this chemical during organogenesis up to the highest dose tested, which was 1,000 mg/kg/day. Furthermore, no maternal toxicity was observed in either of these studies. In a rat multigeneration reproduction study, no reproductive effects were observed at doses up to 1,312.8 mg/kg/day, which was the highest dose tested. However, parental toxicity, characterized by body weight reduction and urinary tract pathology related to calculi formation was reported at this dose; the NOEL was mg/kg/day. In a mouse chronic toxicity/oncogenicity study, sulfosulfuron caused a statistically significant increase in benign mesenchymal bladder tumors (5/60) compared to control animals (0/60) in males at the highest dose tested, which was mg/kg/day. In addition, a statistically significant increased trend for these tumors in males, and kidney tubular adenomas (1/60 in each sex) were observed at the highest doses tested, and 1,388.2 mg/kg/day for males and females, respectively. Although the incidence of the tubular adenomas was not statistically significant, the USEPA Cancer Assessment Review Committee (CARC) considered them to be treatment-related and biologically significant because this tumor is rarely observed spontaneously. In a rat chronic toxicity/oncogenicity study, one transitional cell papilloma and one transitional cell carcinoma of the urinary bladder in female rats were observed at a dose of mg/kg/day. The USEPA CARC considered these tumors to be treatment-related because urinary bladder transitional cell tumors are infrequently observed in historical controls. The USEPA calculated a cancer potency slope factor for sulfosulfuron of 1.03 x 10-3 (mg/kg/day) -1 based on the incidence of the benign mesenchymal bladder tumors in male mice. According to the CARC, this tumor type was selected since it is the only one that exhibited statistical (positive trend and pair-wise) significance. Sulfosulfuron gave negative results in a number of genotoxicity studies. Based on these observations, the USEPA classified sulfosulfuron as a likely human carcinogen. The USEPA conducted both an occupational and residential risk assessment for exposure to sulfosulfuron. For estimating exposures, it was assumed that workers wore personal protective equipment (long-sleeved shirt and long pants, shoes plus socks) as required by the Outrider Herbicide and Certainty Turf Herbicide labels. Dermal and inhalation exposures were estimated assuming 100% absorption of sulfosulfuron by either exposure route. Using the USEPA derived cancer potency slope factor of 1.03 x 10-3 (mg/kg/day) -1 and estimated dermal and inhalation exposures, an increased occupational lifetime cancer risk ranging from 4.2 x 10-8 to 2.0 x 10-6 can be calculated. These values are within the range of what USEPA generally considers to be acceptable (1 x 10-4 or less) for occupational exposures. It should be noted that these values are 1.5-fold higher than what the USEPA derived since we made an adjustment to account for a maximum application rate of pounds sulfosulfuron per acre compared to an application rate used by the USEPA of pounds sulfosulfuron per acre. For noncancer risks, the same occupational inhalation (but not dermal) exposure estimates were compared to a NOEL of 24 mg/kg/day from the rat chronic feeding/oncogenicity study. Margins of exposure (MOEs) so calculated for handling/application of sulfosulfuron in the Outrider or Certainty Herbicide products were greater than 3,000. Generally, the USEPA considers MOEs of 100-fold or greater to provide adequate protection. Noncancer risks from dermal exposure were not assessed since there was no systemic or localized (skin) toxicity at the highest dose tested (1,000 mg/kg/day) in a 28-day dermal toxicity study in rats. Also, no post-

3 Ms. Tann Schafer 3. application occupational exposure risk assessment was conducted since both products are labeled for non-crop uses and therefore there would be no sulfosulfuron-treated crops that would require postapplication handling (e.g., harvesting) by workers. By contrast, post-application exposure in a residential setting may occur for adults and children who, for example, could contact sulfosulfuron residues on residential lawns. For adults, the estimated increased lifetime cancer risks from dermal contact ranged from 9.0 x 10-8 to 1.8 x 10-7, whereas for children, increased lifetime cancer risks from dermal contact and incidental ingestion of sulfosulfuron combined were about 1.6 x The USEPA generally considers an increased lifetime cancer risk level of 1 x 10-6 to be acceptable for the general population. While the estimated increased lifetime cancer risk for children slightly exceeds this level, the derivation included several conservative assumptions (e.g., 14 days per year exposure for 12 years, limited residue dissipation and high residue transfer coefficients) that would tend to overestimate risks. Finally, for incidental oral exposure of children to sulfosulfuron, a MOE of about 1,400 was estimated. The DOH briefly reviewed the environmental fate data on sulfosulfuron. These data indicate that this chemical may have the ability to leach through certain soil types and contaminate groundwater; the adsorption coefficients (K oc ), depending on soil type, ranged from 5.3 to 89 for sulfosulfuron. Accordingly, the Outrider Herbicide and Certainty Turf Herbicide labels contain the environmental hazards statement, This chemical demonstrates the properties and characteristics associated with chemicals detected in groundwater. The use of this chemical in areas where soils are permeable, particularly where the water table is shallow, may result in groundwater contamination. There are no chemical specific federal or New York State drinking water/groundwater standards for sulfosulfuron. Based on its chemical structure, this compound falls under the 50 microgram per liter New York State drinking water standard for unspecified organic contaminants (10 NYCRR Part 5, Public Water Systems). The available information indicates that neither sulfosulfuron nor Outrider Herbicide and Certainty Turf Herbicide are very acutely toxic. Although both the active ingredient and formulated products can cause moderate eye irritation, the products are solid formulations and would be less likely to splash into the eyes of handlers. Also, the labels contain the cautionary statement [C]auses Moderate Eye Irritation, which should help mitigate the potential for this effect. Sulfosulfuron did not cause developmental/reproductive or genotoxic effects. Chronic feeding/oncogenicity studies indicate, however, that this chemical can cause effects on the urinary bladder. In addition, the studies conducted on rodents indicate that sulfosulfuron causes urinary tract tumors. Based on these results, the USEPA classified sulfosulfuron as a likely human carcinogen, and derived a cancer potency slope factor for this chemical. However, a USEPA conducted risk assessment for both occupational and nonoccupational (i.e., post-application residential) exposures to sulfosulfuron indicates that this active ingredient should not pose a significant health risk to workers or the general public as a result of its labeled uses in the formulated products Outrider Herbicide and Certainty Turf Herbicide. Given the above, DOH does not object to the registration of the present labeled uses of sulfosulfuron in these two formulated products, provided that the Department s groundwater staff determines their use does not pose a significant risk of groundwater/drinking water contamination. Given that sulfosulfuron appears to have some oncogenic potential, however, the Department might require a reanalysis of risks and a comparison to other products also registered for these same uses if a registrant seeks to add food crop uses for sulfosulfuron.

4 Ms. Tann Schafer 4. Ecological Risk Assessment: Chemical Description Outrider Herbicide and Certainty Turf Herbicide are identical formulations of herbicides with the active ingredient sulfosulfuron. Both products are 75% active ingredient by weight. In this review, the term sulfosulfuron will refer to technical grade active ingredient (TGAI or AI) unless otherwise stated. Outrider Herbicide is a systemic herbicide used for control of annual and broadleaf weeds in non-crop sites. It is formulated as a water dispersable granule for use on roadsides, utility rights-ofway, airports, fallow areas, ditch banks, dry ditches or canals, fence rows, industrial sites, manufacturing sites, and similar industrial and non-crop sites. No more than 2.66 ounces of Outrider (0.125 lb ai) per acre may be applied in any one year. Certainty Herbicide is a systemic herbicide used for control of annual and perennial grass and broadleaf weeds in commercial and residential turf and other non-crop sites including cemeteries and golf courses. It is formulated as a water dispersable granule for use on bermudagrass turf sites including golf course fairways, golf course roughs, golf course tees, or other bermudagrass areas of a golf course excluding greens. No more than 2.66 ounces of Certainty (0.125 lb ai) per acre may be applied in any one year. Sulfosulfuron is a pyrimidinylsulfonylurea herbicide with CAS number Its density is 1.55, and its solubility in water is 1,627 mg/l. The n-octanol water partition coefficient is Toxicity Sulfosulfuron exhibits low toxicity to nontarget animals. Aquatic life acute 96 hour LC 50 's range between 95 to 110 mg/l for aquatic animals. Chronic aquatic life NOELs ranged from 100 to 102 mg/l for aquatic animals. Sulfosulfuron is very toxic to nontarget aquatic plants. This result is not unusual for a terrestrial herbicide. Environmental Fate and Exposure Sulfosulfuron is removed from aerobic soil by microbial degradation. The mean aerobic microbial degradation half-life of sulfosulfuron is about 51 days. In field dissipation tests, the sulfosulfuron dissipation half-life from treated fields range from 14 to 75 days with a mean of 41 days. The loss of sulfosulfuron from water is from photolysis with a half-life of 1.5 days. The loss from sediments is due to microbial degradation, but it occurs much more slowly. The degradation half-life in days was around 20 days in aerobic water-sediment systems, and 147 days in anaerobic water-sediment systems. Sulfosulfuron is unlikely to bind to aquatic sediments. Birds and mammals might be exposed to sulfosulfuron by feeding directly on treated vegetation, or by feeding on vegetation adjacent to treated fields that received spray drift or direct, inadvertent applications. Aquatic organisms could be exposed to Sulfosulfuron through spray drift or through runoff from treated areas. Sulfosulfuron is soluble in water, and is likely to be transported in runoff.

5 Ms. Tann Schafer 5. Summary and Conclusions Sulfosulfuron does not appear to present any direct significant risks to fish and wildlife. It does not exceed risk thresholds for birds or mammals, even if applied at 10 times the maximum annual application rate. It degrades slowly in soil and aquatic sediment. It does not exceed risk thresholds for aquatic animals, even if direct applications were made to water. It does not exceed risk thresholds for aquatic animals, even if direct applications were made to water at 100 times maximum application rates. The largest concern is the possible impact to aquatic plants. Direct application to water results in concentrations which exceed the LC50 for Duckweed (Lemna gibba). Even a 1% runoff of this pesticide exceeds the LC50 in shallow water (1 foot). These plants are very sensitive to this herbicide, even at low levels. The most likely sites where this could occur would be small, shallow ponds and wetlands adjacent to treated areas. Habitat changes from sulfosulfuron could have impacts on aquatic animals which use these shallow ponds for breeding and early stages of life. While changes in the aquatic plant community are possible, these changes would likely be short in duration. The Environmental Hazards section of the label states for these herbicides Do not apply directly to water, to areas where surface water is present or to intertidal areas... It is important that these herbicides are kept out of water. Environmental Fate Risk Assessment: This application was declared incomplete for purposes of determining impact to groundwater on March 27, The registrant s response indicated that DERs are not available because the original review was an international review, done cooperatively between Canada, the US, Australia and the European Union. The Pest Management Regulatory Agency (PMRA) review of the international data and the EFED Environmental Risk Assessment memorandum dated October 30, 1998 were both provided. The Department s groundwater staff requested additional information regarding the degradates from the registrant which were provided for this review. Therefore, staff found this application as complete as possible for determinating impact to groundwater on September 5, Monsanto is applying to register Certainty Turf Herbicide as a selective herbicide for control of annual and perennial grass and broadleaf weeds in highly managed turf sites: commercial and residential turf and other non-crop sites including: cemeteries, golf course fairways, roughs and tees, or other areas of a golf course excluding greens, sod or turf seed farms and other similar sites. The product contains 75% by weight active ingredient in a granular form. The product is mixed with water and applied as a foliar application at a maximum yearly rate of 2.66 oz product/acre, (or 2.0 oz ai, or 0.12 lb ai/a/yr). Monsanto is applying to register OutRider Herbicide as a selective herbicide for control of annual and perennial grass and broadleaf weeds in non-crop areas. The product contains 75% by weight active ingredient in a granular form. The product is mixed with water and applied as a foliar application at a maximum yearly rate of 2.66 oz product/acre, (or 2.0 oz ai, or 0.12 lb ai/a/yr). The product is labeled for aerial application. The inerts do not appear to be solvent carriers. Sulfosulfuron (N[[4,6-dimethoxy-2-pyrimdinyl-amino]carbonyl]-2-ethylsulfonyl)- imidazol[1,2-a]pyridine-3-sulfonamide) is in the sulfonylurea family, which acts by inhibiting acetolactate synthase (ALS), an essential enzyme in aliphatic amino acid synthesis. Other sulfonylureas include metsulfuron, chlorsulfuron, halosulfuron, foramsulfuron, rimsulfuron, trifloxysulfuron, flazasulfuron, thifensulfuron, and triburonmethy.

6 Ms. Tann Schafer 6. The EFED Environmental Risk Assessment memorandum dated October 30, 1998 indicates that all environmental fate guidelines have been fulfilled except for photodegradation in water, which was supplemental, but additional data is not required at this time. This review was based on the information in that document. Transformation Products sulfonamide 2-(ethylsulfonyl)-imidazo[1,2-a]pyridine-3-sulfonamide aminopyrimidine 4,6-dimethoxy-2-pyrimidinamine desmethyl N-[[4-hydroxy-6-methoxy-2-pyrimidinyl)amino]carbonyl]-2- (ethylsulfonyl)-imidazo[1,2-a]pyridine-3-sulfonamide sulfonic acid 2-(ethylsulfonyl)imidazo[1,2-a]pyridine-3-sulfonic acid guanidine N-[(aminoiminomethyl)]amino]carbonyl]-2- (ethylsulfonyl)imidazo[1,2-a]pyridine-3-sulfonamide urea (4,6-dimethoxy-2-pyrimidinyl)-urea sulfone or ethyl sulfone 2-(ethylsulfonyl)-imidazo[1,2-a]pyridine sulfamic acid [[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]-sulfamic cid oxamic acid 2-iminoalpha-oxo-1(2H)-pyridineacetic acid Technical Review Solubility: The solubility of sulfosulfuron is 17.6 ppm. Hydrolysis: (MRID ) Sulfosulfuron had half-lives of 7.0, 48, 168, and 156 days at ph 4, 5, 7, and 9, respectively. Major degradation products were the sulfonamide and aminopyrimidine moieties. Acidic conditions and higher temperatures favor more rapid hydrolysis. Aqueous Photolysis: In a study found to be supplemental (MRID ), the phototransformation half-life was 33 hours. Many major degradates were found: aminopyrimidine (28.71%), sulfamic acid (20.95%), urea (14.98%), sulfone (28.34%), oxamic acid (15.62%), and sulfonic acid (14.59%). Soil Photolysis: (MRID ) The phototransformation half-life was 139 days. Two major degradates were found: sulfonamide at 13.1% and aminopyrimidine at 11.5%. Aerobic Soil Metabolism: (MRID ) In a sandy loam and a silt loam, the half-lives ranged from 30 to 37 days. Two major degradates were found: sulfonamide at 54.69% and aminopyrimidine at 39.92%. In a second study (MRID ), the calculated half-lives were 92, 194 and 226 in a sandy loam, silt clay loam and clay loam, respectively. No major degradates were found. In a third study (MRID ), the half-life was 51 to 54 days. One major degradate was found: desmethyl 29%. No soil characteristics were provided in any of the summaries. Aerobic Soil Metabolism for Degradates: In a study summary submitted by the registrant, completed June 15, 2006, the aminopyrimidine degradate had a half-life of 7.2 days in a sandy loam

7 Ms. Tann Schafer 7. (ph 7.0, %OC 1.13), 7.7 days in a loam (ph 6.0, %OC 2.2), and 5.9 days in a silt loam (ph 7.35, %OC 1.3). In a study summary submitted by the registrant, completed June 15, 2006, the sulfonamide degradate had a half-life of 45.5 days in a sandy loam (ph 7.0, %OC 1.13), 115 days in a loam (ph 6.0, %OC 2.2), and 50.5 days in a silt loam (ph 7.35, %OC 1.3). The above studies have not yet been reviewed by the USEPA. Anaerobic Aquatic Metabolism: (MRID ) In a pond water system, the half-lives in an Im- and Pd-labeled system were 154 and 136 days, respectively. Three major degradates were provided, in decreasing order: sulfonamide, aminopyrimidine and desmethyl. Aerobic Aquatic Metabolism: (MRID ) In a river and pond water system, the half-lives in an Im- and Pd-labeled system were 20 and 16 days, respectively. The only major degradate found was desmethyl-mon It appears that two studies were done with both the Im- and Pd-labeled systems, but only one set of data were provided. Adsorption/Desorption: (MRID ) Adsorption Kocs were 40, 25, 6.6, 5.3 and 89 in sandy loam (ph 6.8, %OC 0.9), loamy sand (ph 7.3, %OC 0.3), clay loam (ph 7.9, %OC 1.2), loam (ph 7.1, %OC 4.3), and sandy loam soils (ph 5.3, %OC 0.80), respectively. Desorption Kocs were 490, 630, 220, 66, and 590 in sandy loam, loamy sand, clay loam, loam and sandy loam soils, respectively. Adsorption/Desorption of Sulfonamide: (MRID ) Adsorption Kocs were 61, 106, 261, 223 in sandy loam (ph 5.5, %OM 1.46), clay loam (ph 7.1, %OM 3.34), silt loam (ph 7.1, %OM 0.97), and sandy loam soil (ph 8.1, %OM 0.70), respectively. Desorption Kocs were 208, 281, 590 and 456 in sandy loam, clay loam, silt loam, and sandy loam soil, respectively. Adsorption/Desorption of Aminopyrimidine: (MRID ) Adsorption Kocs were 648, 331, 1,612, 234 in silt loam (ph 6.9, %OM 1.78), sandy loam (ph 8.0, %OM 0.58), silty clay loam (ph 6.8, %OM 1.8), and loamy sand soil (ph 5.8, %OM 2.0), respectively. Desorption Kocs were not calculated. Adsorption/Desorption of Sulfonamide/Desmethyl: (MRID ) Adsorption Kocs were 27.4, 26.5, 91.2, and 89.3 in sandy loam, clay loam, silt loam and sandy loam, respectively. Desorption Kocs were 424, 510, 863, and 502 in sandy loam, clay loam, silt loam and sandy loam. Aged Leaching: (MRID ) The results indicated that sulfosulfuron was mobile, degradates desmethyl and sulfonamide were somewhat mobile, and aminopyrimidine had very limited mobility. Terrestrial Field Dissipation: (MRID ) In a sand soil with 0.8% OM and a sandy loam with 1.4% OM, the half-lives were 13 to 41 days. Major degradates in both soils were sulfonamide and guanidine. (MRID ) In a sandy loam with 2.2% OM and a fine sandy loam (no % provided), the halflives were calculated to be 75.1 and 150 days in the sandy loam and 13.6 and 83.3 days in the fine sandy loam. The only degradate analyzed in the study was sulfonamide, and it was not a major degradate.

8 Ms. Tann Schafer 8. Computer Modeling: Staff uses the parameters of the soil with the ph and %OM closest to Riverhead soils. However, the information submitted for the parent did not provide specific soil data, so worst case and best case scenarios were done. By running sulfosulfuron using Riverhead soil, a K oc of 590, a half-life of 37 days and an application rate of 0.12 lb ai/a/yr (best case parameters), the model projected peaks up to about ppb. Changing the half-life to 92 days and the K oc to 89 (worst case parameters), the model projected cyclic peaks of up to about 0.5 ppb. Modeling the degradate sulfonamide, the Koc was 208, the half-life was 45.5 days, and the application rate was lb ai/a/yr (54.69% of applied). The model projected cyclic peaks up to ppb. Modeling the degradate aminopyrimidine, the Koc was 234, the half-life was 7.2 days, and the application rate was lb ai/a/yr (39.92% of applied). The model projected cyclic peaks up to ppb. Label Statements: Both products have the following groundwater statement: This chemical demonstrates the properties and characteristics associated with chemicals detected in groundwater. The use of this chemical in areas where soils are permeable, particularly where the water table is shallow, may result in groundwater contamination. Canadian Comments: The Canadian reviewer felt that the review of the data indicated that this product was persistent, and there was a potential for carryover into the next year. They felt that registration of a moderately persistent herbicide was inappropriate. Summary: Since DERs were not submitted, other information was reviewed. Based on the mobility and persistence characteristics, both the Canadian reviewers, and to a lesser extent, the USEPA reviewers, felt that there was the possibility of groundwater contamination from this product. Running LEACHM using the parameters provided, it appears that the application rate is sufficiently low enough that the labeled use of this product should not negatively affect groundwater. The Department s groundwater staff ran the model at the full labeled rate. However, because these are turf products, the amount of product that makes it through the turf into the soil to become available for leaching, would be less than what was modeled. Therefore, staff have no objection to the registration of these products as labeled. However, staff would want to carefully review any future applications that have uses with less ground cover and/or a higher application rate. Conclusion: The Department concludes that Outrider Herbicide (EPA Reg. No ) and Certainty Turf Herbicide (EPA Reg. No ) should not have an adverse effect on the health of workers or the general public, the fish and wildlife resources, or the ground and surface water of New York State when used as labeled. Therefore, the Department hereby accepts for general use registration in New York State Outrider Herbicide (EPA Reg. No ) and Certainty Turf Herbicide (EPA Reg. No ) both which contain the new active ingredient sulfosulfuron. Enclosed is your Certificate of Pesticide Registration and New York State stamped "ACCEPTED" label. Monsanto Company is reminded that if New York State registration is requested for this product or for any other product which contains sulfosulfuron with an increased application rate

9 Ms. Tann Schafer 9. and/or expanded use sites, the product will be considered a Major Change in Labeling and the Department will require an extensive review. If you have any questions, please contact Samuel Jackling, Chief of our Pesticide Product Registration Section, at (518) Serafini Sincerely, Maureen P Maureen P. Serafini Director Bureau of Pesticides Management Enclosures cc: w/enc. - N. Kim/D. Luttinger - NYS Dept. of Health R. Mungari - NYS Dept. of Ag. & Markets W. Smith - Cornell University, PMEP