Registration of pesticides in the USA is covered by OSCPP harmonised test guidelines (835, 850, 860 & 870 series) some of which correspond with OECD guidelines. As in the EU, radiolabelled compounds are required for some studies such as pesticide residues in crops and livestock whilst for others, such as hydrolysis, water photolysis, dermal penetration and in vivo toxicokinetics; they are preferred, especially where information on transformation and mass balance is required.
The EPA set out the data requirements for Pesticides in 40 CFR 158.1410-Residue chemistry data requirements table, covered by Residue Chemistry Test Guidelines OPPTS 860.1300-Nature of the Residue—Plants, Livestock.
The purpose for conducting metabolism studies is to determine the qualitative metabolic fate of the active ingredient when it is applied to a plant or administered to livestock. To obtain this information, the pesticide is radiolabeled, to follow the compound to see if and where it breaks down within a plant or livestock.
Residue Chemistry Test Guidelines OPPTS 860.1850 Confined Accumulation in Rotational Crops are conditionally required under 40 CFR part 158 for uses of pesticides on food crops. The confined study uses radiolabelled material applied to a small plot. Results of these studies are used to determine whether field studies using non-radiolabeled pesticide are needed.
The Environmental Protection Agency (EPA) regulates all Antimicrobial Pesticides in the USA under the Federal Insecticide Fungicide and Rodenticide Act (FIFRA).
Antimicrobial Pesticides (referred to as Biocides in Europe) are subject to new Data Requirements established in 2013, codified under the Code of Federal Regulations Chapter 40-Protection of the Environment part 158 subpart W.
Antimicrobial Pesticides include disinfectants, fungicides, microbiological water purifiers, santiizers, sterilants, Tuberculocides and Viucides.
Antimicrobial use patterns include both premises and equipment in; Agricultural; Food Handling/storage; commercial; institutional; industrial; and medical. Use in residential and public access premises, swimming pools and aquatic areas is also covered along with use in; human drinking water; industrial processes and water systems; materials preservatives; anti-foul ant paints and coatings; and wood preservatives.
Examples of Data obtained using Radiolabelled compounds PAIRA (Pure Active Ingredient-radio labeled) as the test substance is as follows:
Metabolism and pharmacokinetics: PAIRA or PAI (Pure active Ingredient)
Dermal penetration: Choice
158.2280 Environmental fate
Degradation studies Laboratory
Hydrolysis: PAIRA or TGAI (technical grade active ingredient)
Photodegreadation in water: PAIRA or TGAI
Photodegreadation in soil: PAIRA or TGAI
Leaching and adsorption/de-sorption: PAIRA or TGAI
Metabolism studies Laboratory
Aerobic soil metabolism: PAIRA or TGAI
Anaerobic soil metabolism: PAIRA or TGAI
Aerobic aquatic metabolism: PAIRA or TGAI
Anaerobic aquatic metabolism: PAIRA or TGAI
158.2290 Residue Chemistry
Nature of residues on surfaces: PAIRA or TGAI
Nature of residues in plants: PAIRA
Nature of residue in livestock: PAIRA
Plant metabolism studies are required to determine transformation products that may enter the human diet.
If livestock are exposed to one or more residues differing from those found in animals then one or more additional livestock metabolism studies involving these residues may be required.
Examples of studies using Radiolabeled compounds:
|835 4100 + 4200||Aerobic & Anaerobic Soil Metabolism|
|835 4300 + 4400||Aerobic & Anaerobic Aquatic Metabolism|
|835 2410||Photodegradation in Soil|
|835 1230||Adsorption/Desorption soil|
|835 2240||Photodegradation in water|
|835 2370||Photodegreadation in Air|
|870 7485||Metabolism and Pharmacokinetics|
|870 7600||Dermal Penetration|
|860 1300||Nature of the Residue Plants, Livestock|
|860 1850||Confined Accumulation in Rotational Crops|
Information on the Radiolabelled Test Substance can be found on the Nature of the Radiolabelled Test Substance for Registration Studies page.