5. Risk Assessment of Adjuvants
The application of Clipper Herbicide to emergent and floating vegetation requires the addition of
an adjuvant to the tank mix. The risk characterization of adjuvants that may be used with the
application of this aquatic herbicide is can be found in Appendix 1. The assessment indicates
that even at the high-end estimated spray volumes, the adjuvants commonly used with aquatic
herbicides would not pose risk to aquatic organisms in general, but one could pose risk to
endangered species. The Agri-Dex adjuvant that is used by aquatic applicators operating in
Massachusetts did not exceed LOCs and poses the lowest risk among the four adjuvants that
were evaluated.
6. Risk Mitigation
The product label includes a number of statements and instructions that mitigate risks to nontarget
organisms. In addition to these label instructions, MDAR and MassDEP have additional
recommendations and restrictions, some of which supercede some to the label restrictions.
Label Language
The potential movement from the application area and risks to non-target organisms are addressed
by product label statements, including the following:
MDAR/MassDEP 6 June 2013
Environmental Hazards
The herbicide may be hazardous to plants outside the treatment area. Do not apply to
water except as specified on the label. Do not contaminate water when disposing of
equipment wash waters or rinsate. Ensure that spray drift to non-target species does not
occur.
Application Site Restrictions
Clipper herbicide is not to be applied to flowing water, intertidal or estuarine areas.
Treatment of Waters with Dense Vegetation
Treatment of water bodies with dense vegetation may result in rapid and extensive
decomposition which in turn can result in loss of oxygen in water. A sudden decrease in
oxygen can result in fish suffocation. Therefore, water bodies with dense vegetation
should be treated in sections.
Application to Waters used for Irrigation
To prevent adverse effects on crops, water treated with Clipper Herbicide may not be
used for irrigation purposes until at least five days after application.
Managing Off-Target Movement
To minimize spray drift, the label contains drift reduction advisory information to
address various equipment- and weather-related factors that determine the potential for
spray drift. The factors addressed on the label include control of droplet size, application
height, swath adjustment, wind, temperature and humidity, and temperature inversions.
7. Recommendations and Massachusetts Use Restrictions:
The flumioxazin review prepared by MDAR and MassDEP has examined the environmental fate
and non-target toxicological characteristics of flumioxazin when used as an aquatic herbicide.
These characteristics have been synthesized in risk assessments for human health and pond
ecology.