Is there any scientific reason to not use the iron phosphate based slug baits (Sluggo etc.) near bodies of water (streams, ponds, lakes)? I did some preliminary (not exhaustive) Google research and did not find anything to suggest they cause increased algae growth. Please let me know what you can find on this subject. Are other
water-borne organisms harmed?
The Material Safety Data Sheet for Sluggo indicates that one should avoid
disposal of this product near bodies of water (see Section 13), though
there is not definitive information in Section 12 on the ecological
impacts of the product on algae and other life forms. Here is a link to the PDF document.
See also Grow Smart from King County Hazardous Waste Management on dealing with slugs in gardens.
It does not list Sluggo, Escar-go, or any of the other iron phosphate
products as water pollution hazards, but the MSDS sheet makes me think
there is a potential problem with dumping large quantities. It seems not
enough information is out there, perhaps because the research has not
been done. Here is the page from the Pesticide Action Network database, where you can see that iron phosphate’s eco-toxicity has not been
established.
Here is what the Environmental Protection Agency has to say about iron
phosphate slug baits:
Ecological Effects Hazard Assessment
“A number of ecological effects toxicology data requirements were waived
based on the known lack of toxicity of iron phosphate to birds, fish and
non-target insects, its low solubility in water, conversion to less
soluble form in the environment (soil), and its use pattern (soil
application). An acute oral toxicity study in Bobwhite quail (NOEL & LD50
greater than 2000 mg/kg) indicated that iron phosphate was practically
nontoxic to avian species. Based on these factors, the data requirements
for the toxicity studies in Mallard duck, rainbow trout, freshwater
invertebrates, and non-target insect/honeybees are waived. It is likely
that there will be exposure to ground-feeding non-target insects and
earthworms. Submitted studies involving ground beetles, rove beetles and
earthworms demonstrated that the product will not affect these organisms
at up to two times the maximum application rate.Environmental Fate and Ground Water Data
Exposure assessments on this type of product (biochemical pesticide) are
not performed unless human health or ecological effects issues arise in
the toxicity studies for either of these disciplines. Since no endpoints
of concern were identified, there is no requirement for environmental
fate data.Ecological Exposure and Risk Characterization
Exposure to daphnids and other aquatic invertebrates would not occur
based on current label use directions. Exposure to honeybees is also not
expected to occur, due to the composition and particle size of the
end-use product and its use pattern (soil application). Non-target
insects, such as ground beetles and earthworms, could encounter the
end-use product; however, in tests of rove beetles, ground beetles and
earthworms, no effects were observed at up to twice the maximum
application rate. Thus, the acute risk to aquatic invertebrates,
non-target insects, and earthworms is considered minimal to nonexistent.”
United Nations Environment Programme has information on the impact of Phosphorus on aquatic life, a process called eutrophication. However, the iron phosphate in Sluggo and similar products binds with Phosphorus, which may mitigate the effects in water.