Dimethyl naphthalene-2,6-dicarboxylate

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Persistence:

In an OECD TG 301C study, conducted according to GLP, the degradation of NDC reached 6% (as BOD) and 7% (by HPLC) after 28 and 20, respectively. NDC is not readily biodegradable (Ministry of International Trade and Industry (MITI), 1999). In an OECD 111 study, conducted to GLP, the half life of NDC is 65.9 and 1.04 days in pH 7 and 9, respectively, at 25C. NDC is stable at pH 4 (Ministry of International Trade and Industry, 1996). According to ECHA Guidance Chapter R11 – PBT Assessment, Table R.11-2 Screening criteria for P, vP, B, vB and T, a substance fulfills the screening criteria for Persistence (P) if it does not ultimately biodegrade. NDC, therefore, is considered as Persistent (P) based upon the screening criteria. In addition, according to 1.1.2 of Annex XIII of Regulation EC No 1907/2006, a substance fulfills the very Persistent criterion (vP) when the half life in marine, fresh or estuarine water is >60 days. NDC, therefore, is considered very Persistent (vP) based upon the Annex XIII criteria.

Bioaccumulation:

According to ECHA Guidance Chapter R11 – PBT Assessment, Table R.11-2 Screening criteria for P, vP, B, vB and T, a substance fulfills the screening criteria for bioaccumulation (B) when the Log Pow is >4.5. In an OECD 107 study, conducted according to GLP, the Log Pow of NDC is 3.5 (Ministry of International Trade and Industry (MITI), 1999). NDC, therefore, is not bioaccumulative (B) based upon the screening criteria.

In an OECD 305C study, conducted according to GLP, the BCF of NDC is 6.1 - 63 at a test concentration of 0.1 mg/l. At a test concentration of 0.01 mg/l, the BCF of NDC is 7.1 - 23 (Ministry of International Trade and Industry (MITI), 1999). According to 1.1.2 of Annex XIII of Regulation EC No 1907/2006, a substance fulfills the bioaccumulation criterion (B) when the BCF in aquatic species is higher than 2,000. NDC, therefore, is not bioaccumulative (B) based upon the Annex XIII criteria.

Toxicity:

Based on a NOEL of greater than 1,000 mg/kg bw/day, in accordance with Regulation No 1272/2008, NDC is not classified for reproductive toxicity.

In accordance with Regulation No 1272/2008 Table 3.9.3, NDC is not classified for repeated dose toxicity (oral), based on the NOEL (male and female rats) of >3,000 mg/kg diet (highest dose tested).

Based on the above, NDC is not Toxic (T) in accordance with 1.1.3 of Annex XIII of Regulation EC No 1907/2006.

Likely routes of exposure:

The primary route of NDC release is to wastewater.

NDC may be released to air through use processes; however, the vapour pressure is 0.00033 Pa at 25 ºC and, therefore, air exposure is expected to be negligible.

 

Release to soil may occur from spreading of STP sludge, however this is not advised.