To answer the question, yes, we are very concerned about the fate of secondary consumers should they consume meat or other tissues from swine controlled through the use of sodium nitrite. As stated briefly in the article, SN is a commonly used food preservative and therefore somewhat safe in terms of an active ingredient for a toxicant. But it is highly unstable – therein lies the inherent problem as a substance applied in the environment. Stabilizing it is the trick and something that requires professional chemists which fortunately we have been able to address and overcome. In the environment however, it readily reacts with moisture and heat and degrades into other substances. This is important when we address concerns with scavengers or any secondary consumers. Residual tissue analysis has been done by our partners in Australia and at the National Wildlife Research Center in Colorado. SN tissue residuals from intoxicated swine typically fall well below the amount used in bacon we buy at the store – except for one – stomach tissue. Since SN is activated and absorbed within the stomach lining this tends to make sense. Lucky for us, very few scavengers actually consume stomach tissue – except for vultures. We of course have both Turkey and Black vultures here in Texas and this is reason enough to investigate further. This research will also be conducted at the Kerr Wildlife Management Area and will begin this fall using live, wild, vultures pending approval of our permit from the USFWS. Various levels of SN will be investigated in order to determine a lethal dose if vultures are susceptible to nitrite poisoning. We will then have to determine if this level of SN is even available in stomach tissues from intoxicated swine. This information will be useful in our quest for EPA registration.
A very good question! We should have the answer early next year.
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