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Administrative data

Description of key information

Oral: 1 acute oral study using DTPA acid; 4 acute oral studies using pentasodium DTPA; 2 acute oral studies using pentapotassium DTPA.

Dermal: 1 acute dermal study using pentapotassium DTPA

Inhalation: 1 acute inhalation study using pentasodium DTPA and 1 using a structurally related compound disodium EDTA (EDTA-Na2H2)

Key value for chemical safety assessment

Additional information

The acute oral toxicity of DTPA is low, with LD50 values for the acid and the salt in excess of 2000 mg/kg bw/day. Limited details are available from the studies regarding the potential cause of mortality, however some of the studies did indicate some apparent effects on the kidneys and liver. There is very little difference in the toxicity associated with the pentapotassium, pentasodium salts of DTPA and the acid when one considers the amount of DTPA provided per dose of each substance.

The acute dermal toxicity of DTPA acid and the sodium and potassium salts is very low (LD50 >2000 mg/kg bw). This is consistent with the fact that the dermal penetration of DTPA is very low (<0.1%), as such, dermal dosing of this material will not result in a high enough systemic dose to produce overt toxicity or mortality.

DTPA acid, potassium and sodium salts are not volatile. Therefore the potential for acute exposure to vapours of these substances is remote. In a study performed using pentasodium DTPA, rats exposed for 8 hours to the vapour generated at room temperature did not suffer any adverse effects. Acute inhalation exposure to the solid form of these materials is self limiting due to the particle sizes of the powders (90% >60 micrometers diameter) which will significantly limit the amount inhaled and delivered to the respiratory tract. Also, workers handling the powdered form are required to wear protection (face masks) and this will further limit the possibility for an acute exposure. If such an exposure were to occur it is not expected that it would be more potent than an oral exposure with respect to systemic toxicity.A structurally-related compound EDTA-Na2H2 showed limited inhalation toxicity (i.e. a 6 -h LC30 value of 1000 mg/m3, corresponding to an estimated 4 -h LC50 value between 1000 and 5000 mg/m3).

Justification for classification or non-classification

DTPA-H5 is considered to meet the requirements for classification for acute toxicity as described in the Guidance on the Application of the CLP criteria, Version 4.0 (2013). The proposed classification for DTPA is Acute Tox 4, H332 Harmful if inhaled.