(Methyl (E)-2-[(6-chloro-1,3 pyrimidine-4-oxy)phenyl]-3-methoxyacrylate

Endpoint summary

Description of key information

Dermal, LD50, rat >2000 mg/kg bw  (Robinson)
Inhalation, LC50, rat, 1 hour >1890 mg/m3 (Parr-Dobrzanski) extrapolated in a four- hour inhalation LC50 >470 mg/m3 calculated.

Key value for chemical safety assessment

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

Oral

No oral acute toxicity data are reported for the test substance. Since the inhalation and dermal routes are much more likely to occur in human exposure, and the toxicity determined by either route is insignificant to slight, an experimental determination of the oral LD50 is considered unnecessary for classification and labelling.

Inhalation

For this endpoint the summarised result of one study (CTL, Parr-Dobrzanski) is available, which was conducted under GLP.

One hour of exposure to an atmospheric aerosol concentration of 1890 mg/m3 (mass median aerodynamic diameter 4.86 micrometer) caused no deaths and only slight, transient signs of irritation, therefore the on-hour inhalation LC50 is >1890 mg/m3.

While the full study report is not available, the results are sufficiently detailed and unambiguous as to be reliable with some restrictions.

Since the goal of the study was the assessment of the short-term inhalation hazard, an exposure duration of only one hour was chosen. For aerosols, which are normally not secondarily exhaled, an approximate extrapolation to the usual 4-hour exposure can be based on Haber's rule (Miller FJ, Schlosser PM & Janszen DB (2000): Haber's rule: a special case in a family of curves relating concentration and duration of exposure to a fixed level of response for a given endpoint, Toxicology 149: 22-34). This calculation results in a four- hour inhalation LC50 >470 mg/m3.

Dermal

For this endpoint the summarised result of one study (CTL, Robinson) is available, which was conducted under GLP. While the full study report is not available, the results are sufficiently detailed and unambiguous as to be suitable for classification and labeling.

It reported no mortalities and no significant signs of toxicity at the limit dose of 2000 mg/kg bw. A dermal LD50 > 2000 mg/kg bw is taken forward for classification and labelling.

Justification for classification or non-classification

The available data on Acute Dermal Toxicity are considered reliable and suitable for classification and labeling.

The value for the Acute Dermal Toxicity, LD50 > 2000 mg/kg bw does not lead to the classification of the substance, according to the criteria in Directive 2001/59/EC, Annex VI, 3.2 and according to the criteria for classification under Regulation (EC) No. 1272/2008, Annex I, Part 3, 3.1.2.

No deaths or adverse clinical effects were observed in the test for the Acute Inhalation toxicity. The result of the test gives a LC0> 1.89 mg/L in 1-hour exposure and the extrapolation applying the Haber’s law gives a LC0>0.47 mg/L in 4-hours exposure.

Since no signs of clinical effects up to the upper limit tested were noted, the result indicates that the LC50 value must be significantly higher than the highest concentration tested. Because the study was performed with a maximum concentration < 5 mg/L, and extrapolated from 1-hour exposure data, the result is not considered to be conclusive for classification and labeling.