Registration Dossier

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information

The toxicokinetics of phosphorodithioic acid, mixed O,O-bis(2-ethylhexyl and iso-Bu and iso-Pr) esters, zinc salts has not been directly studied. Oral studies indicate that these salts may be absorbed to a limited extent in the gastrointestinal track resulting in further distribution and metabolism. Because of its high lipophilicity, it may distribute in fatty tissues and be released slowly; however, none of the repeat-dose oral studies report significant effects other than reddened adrenal and pituitary glands and organ weight changes at very high doses, without histopathological evidence to indicate systemic toxicity. The liver is expected to be the primary organ to receive and metabolize the substance, making it more soluble by oxidation and conjugation for eventual release into the bile and into the gastrointestinal tract for elimination. EC 288-917-4 is above the size threshold expected to easily penetrate skin, however with prolonged and concentrated application accompanied by skin irritation, it may produce minimal systemic effects. The degree of absorption of EC 288-917-4 through the skin or gastrointestinal system is likely limited, but regardless of the route of exposure, there is no indication that systemically distributed phosphorodithioic acid, mixed O,O-bis(2-ethylhexyl and iso-Bu and iso-Pr) esters, zinc salts will bioaccumulate.

Discussion on bioaccumulation potential result:

This substance is expected to have a log kow of 8.87 and a high molecular weight of 705.288; both outside the optimal window for intestinal/dermal absorption.The lack of adverse findings following oral dosing (LD50> 3080 mg/kg for acute toxicity; NOAEL 125 mg/kg/d for repeat dose toxicity), or dermal dosing (LD50 > 20,000 mg/kg) may be at least partially due to limited gastrointestinal/dermal absorption of the test substance after treatment, and/or a very low index of inherent toxicity for this substance, and/or its metabolite(s).