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October 30, 2000

ENF 2000-041

TO: County Agricultural Commissioners

SUBJECT: AATREX® NINE-O HERBICIDE LABEL INTERPRETATION

This responds to a request for a label interpretation regarding the use of Aatrex® Nine-O Herbicide (label attached), U.S. EPA Registration No. 100-585-AA, on conifers. The questions concern a statement found in the "Environmental Hazards" section which states: "This product may not be applied aerially or by ground within 66 feet of the points where field surface water runoff enters perennial or intermittent streams and rivers or within 200 feet around natural or impounded lakes and reservoirs."

The first question concerns an established conifer application site that has many areas where surface water runoff (snow melt) starts to converge and form running water. Does the statement above include those areas of convergence or are perennial and intermittent streams only those shown as class 1, 2, or 3 streams?

In general, the point(s) where field surface water runoff enters perennial or intermittent streams/rivers applies to any "Stream" as defined in Public Resources Code (PRC) section 4528.5 (f), attached, which states: "Stream" means a natural watercourse as designated by a solid line or dash and three dots symbol shown on the largest scale United States Geological Survey map most recently published." However, more specifically, the point(s) where field surface water runoff enters perennial or intermittent streams/rivers applies to Classes I, II, III, and IV watercourses as defined in Table I of sections 916.5, 936.5, and 956.5 of the California Forest Practice Rules, Title 14 of the California Code of Regulations, attached. The definition of "Watercourse" is found in California Forest Practice Rules section 895.1. This section states: "Watercourse means any well-defined channel with distinguishable bed and bank showing evidence of having contained flowing water indicated by deposit of rock, sand, gravel, or soil, including by not limited to, streams as defined in PRC 4528 (f). Watercourse also includes man-made watercourses."

The second question asks for a definition of "runoff entry point." The definition of a "runoff entry point" is that point where surface water runoff (snowmelt, rainfall) enters or converges into a perennial or intermittent stream or river.

The registrant, Novartis, was contacted and concurred with the above definition of "runoff entry point." Additionally, the registrant defined the 66 feet buffer requirement. For ground applications, the 66-foot buffer zone would be a "half circle area" that is 66 feet to the left and 66 feet to the right of the "runoff center point" and runs along the edge of the stream or river. For aerial applications, the 66-foot buffer zone would be a "rectangular area" that is 66 feet to the left and 66 feet to the right of the "runoff center point" and runs along the edge of the stream or river.

If you have any questions, please contact the Liaison Senior Pesticide Use Specialist serving your county.

Sincerely,

original signed by

David Duncan, Acting Chief
Pesticide Enforcement Branch
(916) 445-3871

Attachments

cc: Ms. Debra Stubbs, Novartis State Regulatory Manager (w/Attachments)
Mr. Tom Parshley, Novartis Senior Regulatory Manager (w/Attachments)
Mr. Daniel J. Merkley, Agricultural Commissioner Liaison (w/o Attachments)

VA