The US EPA registered ten products containing the new active ingredient isocycloseram, a broad-spectrum contact insecticide proposed for use on agricultural crops, turf and ornamentals, as well as indoor and outdoor uses for commercial, industrial and domestic sites.
Cyclobutrifluram has also been approved. It is a nematicide/fungicide for use on turf, ornamentals, and romaine lettuce, as well as cotton and soybean seed.
Both compounds are considered PFAS under 2021 OECD regulations. Thyroid tests were conducted for Cyclobutrifluram, but are not publicly accessible. Regarding Isocycloseram, the EPA document states:
No references are given, so there is no way for anyone to verify this information. Industry has taken over.“Several studies are available in the database for Isocycloseram that evaluated thyroid toxicity and there were no adverse thyroid effects observed related to thyroid hormone perturbations. No additional thyroid data are needed at this time.”
From the EPA:
Federal RegisterThe thyroid is the most sensitive endpoint in the cyclobutrifluram toxicity database. Following subchronic exposure of rats to cyclobutrifluram, follicular cell hypertrophy in males and females was observed after 28- (331 mg/kg/day) and 90-day (187 mg/kg/day) exposures. Increased thyroid weights were observed in males of the F1 generation while follicular cell hypertrophy was observed in both sexes of the P generation and males of the F1 generation of the multigeneration reproductive toxicity study at 43 mg/kg/day. Maternal thyroid hormones levels (T3, T4, and TSH) were measured in the developmental rat toxicity study up to and including the highest dose tested (250 mg/kg/day) and no adverse changes were observed.
https://www.federalregister.gov/documen ... tolerances
From the comments:
EPN Comments"Generally, in the absence of information on pharmacokinetics and/or pharmacodynamics, it is assumed that humans may be 10 times more sensitive than animals (10X interspecies uncertainty factor). With respect to thyroid effects, it is known that the rat is more sensitive than the human to perturbations in thyroid homeostasis based on the shorter half-life of T4 in rats (12-24 hours) compared to humans (5-9 days), and the lack of the high affinity binding protein thyroxine binding globulin in rats."
https://www.environmentalprotectionnetw ... fluram.pdf