Public Comment. Volume III - Montana Legislature

Study Plan Page 4
Lab Tests
-Target species
-Life stages
-Duration/level of exposure
-Physiological assessment
Data analysis
Herbicide Applicatiort
As a part of railway maintenance, TRRC may use herbicides to control unwanted vegetation in
and around the MCFH. Herbicides work in several different ways (Pike and Hager, circa 1998).
Of obvious concern to MCFH is the biological damage that can be inflicted to phytoplankton and
periphyton in its forage ponds. Since April 1983, MCFH has used Branum Lake as a forage fish
pond. Hatchery operations call for the pond to be flooded early in the year (April) to establish
plankton populations that will serve as forage for hatchery fry and fingerlings. Herbicide use
may pose a health threat for the phytoplankton that support zooplankton communities used as
forage for fish. The implications for the feeding success during the first weeks of life for fish
may be critical for survival (DeVries et al. 1998). There is also concern for determining the
effects to fish from toxicity levels which may result in stress or mortality. Finally, there should
be a determination of the risk of bio-accumulation in the food chain because fish are stocked in
reservoirs and lakes that are exploited by predators (other fish, eagles, otters, etc.) and anglers
who may consume their catch.
Specific questions that herbicide studies should address include:
What types of herbicides are to be used by TRR, in what concentration, how often, and in
what mode of application?
What is the potential for contamination into forage and fish ponds?
What effect will herbicide runoff have on plankton and macroinvertebrate communities?
What is the effect of herbicide runoff to fish?
Information produced from herbicide studies should include:
A list of herbicides TRR will use,
Descriptions of mode of application, concentrations, and time schedule,
Determination of runoff and concentration potential to ponds,
Results of bioassay tests that determine lethal concentrations to fish, plankton, and
macroinvertebrates, and
EPA studies on biological effects for each herbicide,
Obiectives
The objectives of herbicide studies should be to determine how TRR's application of these
chemicals may affect plankton populations and fish health in MCFH ponds. .
An herbicide assessment related to MCFH operations is important in determining whether
alternatives to vegetation control are warranted. This assessment should involve determining the
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