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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Workers - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
0.11 mg/m³
Most sensitive endpoint:
acute toxicity
Route of original study:
By inhalation
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
12.5
Dose descriptor starting point:
NOAEC
Value:
5.6 mg/m³
Modified dose descriptor starting point:
NOAEC
Value:
1.4 mg/m³
Explanation for the modification of the dose descriptor starting point:

An acute rat inhalation study (3 hours exposure time) that includes dose response relationships for relevant sub-lethal effects (cholinesterase inhibition) has been identified and a relevant NOAEC has been set.In general, methomyl’s effects are primarily acute in nature and are related to the inhibition of cholinesterase which occurs quickly and reverses rapidly following either oral or inhalation exposure. From the battery of studies (both short-term and long-term) conducted on methomyl the most sensitive adverse endpoint is cholinesterase inhibition and therefore the acute inhalation study selected should be relevant for assessing long-term inhalation systemic effects without the need for assessment factors for duration extrapolation. Within the EFSA Scientific Review Report, 2006, 83, 1-73, (Conclusion on the peer review of methomyl), a NOAEL from an acute study was considered as an appropriate basis upon which to derive longer term reference values such as the ADI and systemic AOEL with only the need to use uncertainty factors for inter and intra species variation.

The NOAEC in the acute inhalation study was selected based on % brain cholinesterase inhibition observed in an acute inhalation study conducted in rats. In this study brain cholinesterase inhibition was more sensitive than RBC inhibition and a NOAEC of 5.6 mg/m3was derived. In the study rats were exposed for 3 hours. For worker assessment, the inhalatory NOAEC rat needs to be corrected for the difference between respiratory rates under standard conditions and under conditions of light activity. With the assumption that inhalation absorption of methomyl in the rat is equal to inhalation absorption in humans the following calculation is conducted:

 

Corrected NOAEC = 5.6 mg/m3* (3 h/d / 8h/d)*(6.7m3/10m3)

                   = 1.4 mg/m3

AF for dose response relationship:
1
Justification:
A factor of 1 is appropriate since the dose descriptor is a NOAEC
AF for differences in duration of exposure:
1
Justification:
see reasoning above
AF for interspecies differences (allometric scaling):
2.5
Justification:
or differences not related to allometric scaling
AF for intraspecies differences:
5
Justification:
effects for workers
AF for the quality of the whole database:
1
Justification:
A factor of 1 is appropriate because the database is adequately robust.
Acute/short term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
0.3 mg/m³
Most sensitive endpoint:
acute toxicity
Route of original study:
By inhalation
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
12.5
Dose descriptor starting point:
NOAEC
Value:
5.6 mg/m³
Modified dose descriptor starting point:
NOAEC
Value:
3.8 mg/m³
Explanation for the modification of the dose descriptor starting point:

An acute rat inhalation study (3 hours exposure time) that includes dose response relationships for relevant sub-lethal effects (cholinesterase inhibition) has been identified and a relevant NOAEC of 5.6 mg/m3has been set based on % brain cholinesterase inhibition. For worker assessment, the inhalatory NOAEC rat needs to be corrected for the difference between respiratory rates under standard conditions and under conditions of light activity. The study duration of 3 hours maybe conservative in derive the acute DNEL. With the assumption that inhalation absorption of methomyl in the rat is equal to inhalation absorption in humans the following calculation is conducted:

 

Corrected NOAEC = 5.6 mg/m3* (6.7m3/10m3)

                   = 3.8 mg/m3

AF for dose response relationship:
1
Justification:
A factor of 1 is appropriate since the dose descriptor is a NOAEC
AF for interspecies differences (allometric scaling):
2.5
Justification:
for differences not related to allometric scaling
AF for intraspecies differences:
5
Justification:
effects for workers
AF for the quality of the whole database:
1
Justification:
A factor of 1 is appropriate because the database is considered to be adequately robust

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Workers - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
0.5 mg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Dermal
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
180
Dose descriptor starting point:
NOAEL
Value:
90 mg/kg bw/day
AF for dose response relationship:
1
Justification:
A factor of 1 is appropriate since the dose descriptor is a NOAEC
AF for differences in duration of exposure:
6
Justification:
A factor of 6 is appropriate to extrapolate from a sub-acute to chronic
AF for interspecies differences (allometric scaling):
2.4
Justification:
for allometric scaling related to rabbit.
AF for other interspecies differences:
2.5
Justification:
for differences not related to allometric scaling
AF for intraspecies differences:
5
Justification:
effects for workers
AF for the quality of the whole database:
1
Justification:
A factor of 1 is appropriate because the database is considered to be adequately robust
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:
low hazard (no threshold derived)

Additional information - workers

General Population - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

General Population - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified

General Population - Hazard via oral route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

General Population - Hazard for the eyes

Local effects

Hazard assessment conclusion:
no hazard identified

Additional information - General Population