N,N-dimethylpyridin-4-amine

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

A determination that the substance is not readily biodegradable is based upon results from a closed bottle ready biodegradability assay, and is supported by the predictions of QSAR modelling. The closed bottle test showed 0% degradation in 28 d using activated sludge as the inoculum. This finding is supported by the QSAR model BIOWIN v4.10, which predicted that the substance was not readily biodegradable; the values for BIOWIN 2 (0.0700) and BIOWIN 6 (0.1441) were each below 0.5 (indicating that the substance does not degrade fast), although the BIOWIN 3 module result (2.4602), indicating ultimate degradation in the timeframe of weeks to months, was above the screening criterion (< 2.2), the value below which a substance is predicted to be persistent. Therefore although a definitive determination of persistence has not been made, the substance may be presumed to be potentially persistent (potentially P) and potentially very persistent (potentially vP) in the absence of additional information. 

 

Screening-level data indicate that the substance is not bioaccumulative (not B) and not very bioaccumulative (not vB). These screening-level determinations are based on an experimentally-determined log K_owof 1.34, which is substantially below the screening criterion (log K_ow≤4.5) for both “not B” and “not vB”. 

 

The substance has been shown to be not toxic (not T) with respect to the definitive criteria for mammalian toxicity. The substance has not been classified as carcinogenic (category 1A or 1B), germ cell mutagenic (category 1A or 1B), toxic for reproduction (category 1A, 1B or 2), or exhibiting chronic toxicity (STOT-RE category 1 or 2). Screening-level data indicate that the substance is presumably not toxic (not T) based on aquatic endpoints; the lowest L(E)C50 value from acute toxicity data from three trophic levels (i.e., the ErC50 = 4.22 mg/L, based on algal growth inhibition in Pseudokirchneriella subcapitata) is above the criterion (L(E)C50 ≥ 0.1 mg/L) for demonstrating that the substance is not toxic (not T); however, this is not a definitive determination, as long-term aquatic toxicity testing data are not available. 

 

Therefore, although a complete definitive determination cannot be made with respect to all endpoints, screening level criteria indicate that the substance is “potentially P”, “potentially vP”, “not B”, “not vB”, and “not T". It is not necessary to have definitive criteria for all five endpoints to make the determinations as to whether the substance is “not PBT” and “not vPvB”. The determination based on screening criteria only 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.

 

In summary, based on data available to date, the substance is “not PBT” (potentially P, not B, not T) and is “not vPvB” (potentially vP, not vB).

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