Benzophenone-3,3':4,4'-tetracarboxylic dianhydride

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Persistence:The results from the ready biodegradability test (screening criterion) indicated negligible biodegradation. Although the hydrolysis test (additional consideration) indicated rapid hydrolysis at a circumneutral pH and an environmentally relevant temperature (20^oC), this information is not sufficient to show that the degradation products resulting from hydrolysis are not persistent in the environment. The BIOWIN model predicts that the substance is not readily biodegradable, based on the results of the seven modules in the model. However, the results of the BIOWIN 3 module indicate that ultimate degradation is expected to occur in the timeframe of weeks to months, which does not met the screening criterion for persistence and is indicative that the substance is not likely to be very persistent in the environment. 

Therefore, no definitive determination on persistence can be made based on available information. However, in the absence of a definitive determination, the substance may be described as potentially “persistent” (“P”) and potentially “very persistent” (“vP”), based on the screening criteria for ready biodegradability, although the predictions of the BIOWIN 3 module indicate that the substance is unlikely to be very persistent in the environment.. 

 

Bioaccumulation:There are sufficient data regarding the octanol-water partitioning coefficient (log K_owscreening criterion) to determine that the substance is “not bioaccumulative” (“not B”) and “not very bioaccumulative” (“not vB”). The predicted log K_owof 3.30 is below the screening criterion of log K_ow≤4.5 to indicate that the substance is “not B” and “not vB”.  Bioaccumulation is not a potential concern for benzophenone tetracarboxylic acid (BTA), the hydrolysis product of the substance (benzophenone tetracarboxylic acid dianhydride); the predicted log Kow for BTA of 1.30 is substantially below the screening criterion of log Kow ≤ 4.5, demonstrating that the hydrolysis product of the substance is “not B” and “not vB”.

 

Toxicity:A definitive determination regarding the mammalian toxicity of the substance indicates that the substance is not toxic. With respect to mammalian toxicity, BTDA has not been classified as “carcinogenic, mutagenic or toxic for reproductive toxicant” (CMR) and has not been classified as “STOT RE”, T, R48” or “Xn, R48” with respect to chronic exposures; these are definitive determinations of “not T” with respect to mammalian toxicity.

 

The results of the short-term aquatic toxicity tests indicate that the substance is presumably “not toxic” (“not T”) when compared to the screening criteria for short-term aquatic toxicity.  The lowest of the acute toxicity L(E)C₅₀values is from an algal growth inhibition assay with E_rC₅₀= 68.6 mg/L, which is more than three orders of magnitude above the definitive criterion of L(E)C₅₀< 0.01 mg/L, and more than two orders of magnitude above the screening criterion of L(E)C₅₀< 0.1 mg/L. Since the substance does not exhibit the potential for bioaccumulation and has been shown to undergo rapid hydrolysis in the environment, the substance may be considered to be presumably "not T" for both acute and chronic exposures. 

 

Conclusions:Any determination based on screening criteria requires that “each of the three properties persistency, bioaccumulation and toxicity need to be considered in conjunction” (Chapter R.11, “PBT Assessment”,Guidance on information requirements and chemical safety assessment, ECHA, May 2008, Section R.11.1.2.2, p. 13). Therefore, BTDA is considered to be “not PBT “(potentially P, not B and presumably not T) and “not vPvB” (potentially vP, not vB).