Pesticides detected in Montana groundwater during 2011 testing

Detected in Helena and Billings, Dichlorprop targets post- emergent broadleaf weeds and brush (both annuals and perennials). Used for weed control on residential lawns, sod farms, roadsides, industrial sites, rights-of-way, and forests. The United States uses roughly 4 million pounds of dichlorprop-p annually. An estimated 60% of this is used on residential lawns. Not used in agricultural applications. Dichlorprop-p

The EPA classifies this compound as a toxin (Class D). Review of available data has derived a interim human health standard of 0.3mg/L. DEQ preliminary calculations have been confirmed by EPA Region 8. Dichlorprop-p a herbicide

Myclobutanil- a fungicide First detected in the Billings area, Myclobutanil is a fungicide. It has a number of food crop applications (grapes, strawberries and blueberries) and commercial or residential landscaping applications.

Myclobutanil The EPA considers it a toxin (class E) Review of available data has derived a interim human health standard of 0.2mg/L. DEQ preliminary calculations have been confirmed by EPA Region 8.

Fipronil- an insecticide Detected in several locations (Gallatin River, Missoula and Helena) Fipronil is used to control a variety of insects including ants, beetles, cockroaches, fleas, ticks, termites, mole crickets, thrips, rootworms, and weevils. Fipronil may be found in turf products, seed treatments, pet care products, baits, and termite treatments It is registered for use on commercial and residential turf. There are currently three tick and flea control products with fipronil for use directly on pets.

Fipronil The EPA does consider this compound a carcinogen (class C). Review of available data has derived a interim human health standard of mg/L. DEQ preliminary calculations have been confirmed by EPA Region 8.

New Pesticides under MACGWPA from , already approved as action items Bromoxynil Dimethoate Fluroxypyr Pyroxsulam

Proposed Revisions of I class MACGWPA pesticides for 2012 DEQ-7, already approved as action items Imazapyr Imazamethabenz- methyl ester MCPP Metalaxyl Metsulfuron Methamidophos Mirex Thifensulfuron Methyl Tribenuron, Methyl Triclopyr Clopyralid Nicosulfuron Oxydemeton, methyl Primisulfuron methyl Triasulfuron