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2,6-Diisopropylnaphthalene
NYS DEC Letter - Registration of the New Active Ingredient 8/04

New York State Department of Environmental Conservation
Division of Solid & Hazardous Materials

Bureau of Pesticides Management
Pesticide Product Registration Section
625 Broadway, Albany, New York 12233-7257
Phone 518-402-8768     FAX 518-402-9024
Website: http://www.dec.state.ny.us/website/dshm/pesticid/pesticid.htm
E-Mail: ppr@gw.dec.state.ny.us

August 11, 2004

CERTIFIED MAIL
RETURN RECEIPT REQUESTED


Ms. Christine Coon
State Registration Manager
Loveland Products, Inc.
P.O. Box 1286
Greeley, Colorado 80632-1286

Dear Ms. Coon:

Re: Registration of the New Active Ingredient 2, 6-diisopropylnaphthalene (2,6-DIPN) Contained in the Pesticide Product Amplify® (EPA Reg. No. 34704-843)

    The New York State Department of Environmental Conservation (Department) has completed a technical review of the application (received 02/03/04) and data package submitted in support of registration of the referenced product in New York State. Amplify® (EPA Reg. No. 34704-843) contains the new biochemical active ingredient 2, 6-diisopropylnaphthalene (2,6-DIPN).

    The Department hereby accepts Amplify® (EPA Reg. No. 34704-843) for registration as a "Restricted Use" pesticide product in New York State. Due to the complex label requirements for its use, Amplify® is classified as a State "Restricted Use" pesticide product pursuant to 6 NYCRR Part 326.23(e). The technical review follows.

    Amplify® (99.7% 2,6-DIPN) is a plant growth regulator applied via aerosol fog to treat potatoes for sprout inhibition during storage. Use of Amplify® is limited to one treatment during potato storage season at 16.6 ppm or 1.0 pound 2,6-DIPN per 600 hundredweight of potatoes.

    The registration package was deemed complete for purposes of technical review on March 25, 2004. Pursuant to the review time frame specified in Environmental Conservation Law (ECL) 33-0704.2, a registration decision date of August 22, 2004 was established.

    Toxicological, ecotoxicity and environmental fate risk assessments were conducted for 2,6-DIPN and the Amplify® end-use product.

TOXICOLOGICAL RISK ASSESSMENT:     Amplify® contains the new active ingredient 2,6-diisopropylnaphthalene (2,6-DIPN) and is labeled for treating potatoes to inhibit sprouting during storage. Amplify® is not intended for use outdoors or in other non-enclosed areas.

    Limited toxicity testing was required for federal registration of Amplify® since the United States Environmental Protection Agency (USEPA) classified this product as a biochemical pesticide. This classification was based on the active ingredient's structural and functional similarity to several chemicals (i.e., 1-isopropyl-4,6-dimethylnaphthalene, I-methyl-7-isopropylnaphthalene and 4-isopropyl-1,6-dimethylnaphthalene) which are naturally-occurring plant growth regulators found in plant tissues.

    The Amplify® product is solely comprised of the active ingredient 2,6-DIPN (with a minor amount of a chemically related impurity). This product was not very toxic to laboratory animals following acute oral, inhalation and dermal exposures. It also was neither very irritating to the skin or eyes (tested on rabbits) nor was it a skin sensitizer (tested on guinea pigs). In a subchronic oral toxicity study of 2,6-DIPN in rats, decreases in body weight gains and food consumption, and adrenal gland (increased organ weight and cortical hypertrophy) and kidney (tubular nephrosis) effects were reported at 208 and 245 milligrams per kilogram body weight per day (mg/kg/day) for males and females, respectively. The respective no-observed-effect levels (NOELS) were 104 and 121 mg/kg/day. The USEPA Office of Pesticide Programs calculated an oral reference dose (RfD) for 2,6-DIPN of 1 mg/kg/day based on the NOEL of 104 mg/kg/day and an uncertainty factor of 100. This RfD value has not yet been placed in the USEPA's Integrated Risk Information System (IRIS). An extra ten-fold uncertainty factor to account for the absence of chronic toxicity data was not used by USEPA to determine an RfD for 2,6-DIPN because the compound is classified as a biochemical pesticide with a nontoxic mode of action, and it was deemed not to have the toxicity, use and exposure potential that would trigger USEPA to use the additional factor.

    2,6-DIPN caused some developmental toxicity in the offspring of pregnant rats administered this compound during organogenesis at doses that also caused maternal toxicity. In rats, reduced fetal body weights and a skeletal malformation (cartilaginous changes in the vertebral column) of uncertain relevance were reported at a dose of 500 mg/kg/day; the NOEL was 150 mg/kg/day. Maternal animals had reduced body weight gains and food consumption at 150 mg/kg/day; the NOEL was 50 mg/kg/day. 2,6-DIPN was negative in several genotoxicity assays. A search of the toxicological literature did not find any additional information on this chemical.

    The USEPA established tolerances for 2,6-DIPN residues in or on potato peel and whole potato at three parts per million (ppm) and 0.5 ppm, respectively. Both the acute (aPAD) and chronic population adjusted dose (cPAD) for 2,6-DIPN are 0.1 mg/kg/day based on the RfD of 1 mg/kg/day and an additional uncertainty factor of 10 to account for the absence of a rabbit developmental toxicity study and a rat multigeneration reproduction study. The USEPA estimated acute dietary exposure to be 23.11 % of the aPAD for the general U.S. population and 53.49% of the most highly exposed population, children one to six years of age. Chronic dietary exposure to 2,6-DIPN residues was estimated to be 6.9% for the general U.S. population and 23.3% for children one to six years old.

    An occupational risk assessment was not submitted in the registration package for this product. However, negligible occupational exposure to 2,6-DIPN is expected from use of the Amplify® product given that it is only applied in commercial potato warehouses using remote aerosol-generating equipment. Also, occupational exposure from entering a treatment area prior to its ventilation is mitigated by the label requirement for personal protective equipment including the use of either a respirator approved for pesticides (MSHA/NIOSH approval number prefix TC-23G), or a canister approved for pesticides (MSHA/NIOSH approval number prefix TG-14G).

    There are no chemical-specific federal or State drinking water standards for 2,6-DIPN. Based on its chemical structure, 2,6-DIPN 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 Amplify® product was not very acutely toxic, irritating to the skin or eyes, or a skin sensitizer. 2,6-DIPN did cause some subchronic and developmental toxicity, but at relatively high doses and in the case of developmental toxicity, at doses which also caused maternal toxicity. The labeled use of the Amplify® product is not expected to pose significant risks to the general population or to workers. However, given the complex label requirements for its use, the New York State Department of Health recommends that Amplify® either is considered for restricted use status in New York State or that some other means of limiting its availability to those capable of using it properly is implemented.

ECOTOXICITY RISK ASSESSMENT:     Amplify® is used to inhibit potato sprouting during storage in warehouses and other closed spaces. Using an existing or temporary ventilation system it is applied inside sealed structures as a thermal aerosol fog by forcing treated air to flow through potato piles. The interior air is recirculated through the potatoes until all the aerosol has dissipated.

    2,6 Diisopropylnaphthalene (2,6-DIPN) is classified as a biochemical pesticide due to its structural and functional similarity to naturally occurring substituted naphthalene plant growth regulators found in plant tissues. 2,6-DIPN has very low toxicity to mammals with both acute and chronic exposures. All ecotoxicity and environmental fate testing requirements were waived for federal registration.

    The applicant submitted a short assessment of ecological risks based on toxicity data established for naphthalene acetic acid (NAA), a close 2,6-DIPN analog. NAA, which is slightly more toxic to mammals than 2,6-DIPN, is practically nontoxic to quail and Daphnia, and is slightly toxic to trout. The trout and Daphnia NAA LC50s are 57 ppm and 360 ppm, respectively. 2,6-DIPN has a water solubility of 0.02 ppm so acutely toxic water concentrations cannot be achieved. 2,6-DIPN is a volatile chemical which will gradually dissipate from treated facilities as vapor. Air vents in potato storage warehouses are typically about 20 feet above the ground so the probability that measurable residues will be deposited on surrounding vegetation or in surface waters is very low.

    Fish or wildlife resources are unlikely to be adversely affected or significantly exposed to 2,6-DIPN by use of this product as labeled.

ENVIRONMENTAL FATE RISK ASSESSMENT:     Loveland Products, Inc. (formerly Platte Chemical Company), is applying to register Amplify®, a biochemical pesticide, as a potato sprout inhibitor on stored potatoes. Product labeling prohibits use on seed potatoes. Amplify® contains 99.7% active ingredient by weight and is applied as a single fogging application at 1.0 lb ai per 600 cwt of potatoes (1,002 bushels or 60,120 lb of potatoes [1 cwt = 1.67 bushels = 60 lb]).

    The USEPA has determined that this is a biochemical pesticide, and environmental fate and groundwater data (Tier II, (40CFR Section 158.690(d)(2)(vii through xv)) are waived on products that are biochemical in nature. Since environmental fate data were not necessary, there is no impact to the groundwater to be assessed.

DISCUSSION:     The toxicological review noted that the ventilation and reentry requirements should be made more prominent on the Amplify® label as improper precautions or procedures during these operations might pose health risks to workers. This concern is mitigated by classification of Amplify® as a "Restricted Use" product pursuant to 6 NYCRR 326.23(e). As such, Amplify® may only be sold to or used by certified pesticide applicators or persons under their direct supervision.

REGISTRATION ACTION:     The Department hereby accepts Amplify® (EPA Reg. No. 34704-843) for registration as a "Restricted Use" pesticide product in New York State. Enclosed for your files are the Certificate of Pesticide Registration and New York State stamped "ACCEPTED" label.

    Amplify®, as noted in the "RESTRICTION" column on the Certificate, is classified as "Restricted Use" under rules and regulations 6 NYCRR Part 326.23(e). As such, this product is restricted in its purchase, distribution, sale, use and possession in New York State.

    According to Department regulations specified in-6 NYCRR 326.3(a): "It shall be unlawful for any person to distribute, sell, offer for sale, purchase for the purpose of resale, or possess for the purpose of resale, any restricted pesticide unless said person shall have applied for, and been issued a commercial permit." If you require information regarding a commercial permit, please contact Thomas Lynch, Chief, Pesticide Certification Section, at (518) 402-8748. The Pesticide Reporting Law (PRL) requires all certified commercial pesticide applicators to report information annually to the Department regarding each pesticide application they make. Commercial pesticide retailers are required to report all sales of restricted pesticide products and sales of general use pesticide products to private applicators for use in agricultural crop production. If no sales are made within New York State, a report still must be filed with the Department indicating this is the case. Information relating to the Pesticide Reporting Law or annual report forms is available at the Department's website at http://www.dec.state.ny.us or from the Pesticide Reporting Section, at (518) 402-8765.

    Please note that a proposal by Loveland Products, Inc., or any other registrant, to register a product containing 2,6-DIPN, whose labeled uses are likely to increase the potential for significant exposure to humans or impact to the environment, would constitute a major change in labeled (MCL) use pattern. Such an application must be accompanied by a new application fee and meet the requirements specified in 6 NYCRR Part 326.17.

    Please contact Samuel Jackling, Chief of our Pesticide Product Registration Section, at (518) 402-8768 if you have any questions.

Sincerely,

Maureen P. Serafini
Director
Bureau of Pesticides Management

Enclosures
cc: w/enc. - N. Kim/D. Luttinger, NYS Dept. of Health
R. Zimmerman/R. Mungari, NYS Dept. of Ag. & Markets
W. Smith, Cornell University, PSUR

Amplify Label - 8/04 (PDF)