County Roads Department Investigated for Use of Prohibited Pesticides Near Wellheads: Part IV

Pesticide Episode Incident Report Reveals Numerous Incriminating Details Discovered During Investigation of County Roads Department Roadside Right-of-Way Vegetation Control Program.

Investigation Conducted by County Agricultural Commissioner’s Office Exposes Multiple Violations by County Roads Department of the California Code of Regulations for Wellhead Protection, Groundwater Protection, General Standards of Care, and Protection of Persons, Animals, and Property.

The visible strip of dead vegetation is the result of prohibited use, in March 2016, of preemergent pesticides for control of vegetation in the roadside draining facilities by the County Roads Department. Note the proximity of the wellhead’s storage tank to the roadway’s edge, and the wide strip of dead vegetation. (Photo April 26, 2016)

Published: 7 February 2018–2220 PST (Rev. 12 April 2018–0115 PST)

(Table of Contents)

Chapter 4: Findings Narrative of the Senior Agricultural Biologist, County Agricultural Commissioner’s Office (edited for clarity)

Site visits, photographic evidence, pesticide use records, soil sample analysis, and statements of County Roads Department employees confirmed that:

• On March 17, 2016 the Road Crew Lead Worker, an employee of the County Roads Department, applied an herbicide solution that contained Aminopyralid, triisopropanolamine salt (Milestone) (EPA Reg. №62719–519) and Penoxsulam (Pindar GT) (EPA Reg. №62719–611) within 25 feet of an unprotected wellhead subject to surface water runoff from rainfall.
• On the product labeling, both Milestone and Pindar GT indicated preemergent activity.
• Milestone contained the chemical Aminopyralid, triisopropanolamine salt and Pindar GT contained the chemical Penoxsulam.
• Aminopyralid, triisopropanolamine salt and Penoxsulam are on CCR § 6800(b) Groundwater Protection List.
• Penoxsulam use within 100 feet of wellheads was prohibited by CCR § 6609 Wellhead Protection effective May 27, 2004.
• Aminopyralid, triisopropanolamine salt (Milestone) was added to the list of prohibited preemergent herbicides on October 1, 2014.
• The pesticide application site paralleled the road and extended from the edge of the roadway to approximately four feet in.
• The wellhead was situation within a six foot square concrete pad.
• The edge of the concrete pad was 17 feet from the edge of the roadway, and the wellhead within the pad was 22 feet away from the edge of the roadway.
• Aminopyralid, triisopropanolamine salt (Milestone) residue was found three feet, eight inches from the edge of the roadway. This was less than 14 feet from the edge of the wellhead’s concrete pad despite the 100 foot regulatory prohibition.
• There was no protective berm around the wellhead, and there was a downhill slope from the application site that would allow surface water runoff to move to the perimeter of the the wellhead towards the wellhead and contact or collect around the concrete pad.
• In an interview with the Senior Agricultural Biologist, the Road Operations Support Services Supervisor acknowledged that he knew several wellheads existed near the areas his employees were treating with herbicides, however, he did not have the specific knowledge that two herbicides being used had active ingredients with preemergent qualities that were prohibited from being applied within 100 feet of wellheads that were unprotected from surface water runoff.
• The Road Operations Support Services Supervisor stated that the subject of unprotected wellheads was never discussed with the Pest Control Advisor.
• An interview with the Pest Control Advisor indicated that he was not aware of the presence of wellheads that were subject to, and unprotected from, surface runoff due to rainfall.
• The roadsides treated by the County Roads Department had a significant number of unprotected wellheads.
• In the one mile segment of the road where this incident had been reported and subsequently investi, there were a total of five wellheads and/or the associated water storage tanks that were plainly visible from the roadway.
• In the Pest Control Advisor’s field observations, he concentrated on the weeds that needed to be controlled and the efficacy of the herbicides used in the application.
• The Pest Control Advisor did not discuss with the Road Operations Support Services Supervisor, or specifically note in his 2015 and 2016 Pest Control Recommendations, that the pesticides listed had a prohibition against application within 100 feet of unprotected wellheads subject to rainfall surface runoff.
• Had the Pest Control Advisor specifically addressed the wellhead vulnerability issue with the Road Operations Support Services Supervisor, he would have known that this hazard existed.
• This was a failure to warn of the possibility of damages by the pesticide application that reasonably should have been known by the agricultural Pest Control Advisor to exist.

Next: County Roads Department Investigated for Use of Prohibited Pesticides Near Wellheads: Part V