Ethyl formate

Endpoint summary

Description of key information

Bioaccumulation: aquatic / sediment

The bioaccumulation study in Salmon gairdneri (rainbow trout) was conducted for determining the BCF (bioaccumulation factor) value of test chemical (from peer reviewed journal, handbook and secondary source).Salmon gairdneri (rainbow trout) was used as a test organisms for the study. BCF value of test chemical was measured using a logKow value of 0.23. The study was performed at a temperature of 12°C for 2-6 hrs. Radiolabeled test chemical was used for the study.All radiolabeled chemicals (purity > 98%) used in these experiments were supplied by Pathfinder Laboratories. Specific activities were confirmed by liquid scintillation counting (LSC) then gas chromatographic (GC). Analyses were done on a Hewlett-Packard 5730A automatic CC with Model 3552A data system. Test chemical was chromatographed on a Tenax-CC 60/80 mesh 3-ft X 2-mm column after direct aqueous injection. Rainbow Trout used in the study weighed 660 to 840 g. Fishes were fed with Glencoe mills trout feed for upto 24 hr before experimentation. The fish were on a 12-hr photoperiod (incandescent) at an intensity of 11.0 Ix at the air-water interface. All of the trout were acclimated to a temperature of 1 I to 12°C for several months prior to experimental use. Plexiglass respirometer metabolism chamber was used as a test vessel for the study. Chemicals were individually introduced into the respirometer-metabolism chambers at water concentrations 10 to 100 times lower than reported 96-hr LC50 values and lower than solubility value. The duration of exposure to each chemical was 2 to 6 hr during which the inspired and expired water of each fish was monitored three to six times to determine the amount of each chemical removed by a fish after flowing once across its gills (extraction efficiency). At the end of each 3- to 6-hr period, chemical dosing was stopped and the chambers were flushed with control water for 1 hr followed by initiation of dosing with the next chemical to be tested. Two separate experiments were conducted utilizing two fish per experiment. Two fish out of the four were reexposed with selected chemical near the end of each 2 to 4 day experiment to see if changes in uptake efficiency has occurred for a given chemical over the duration of the experiment. Uptake efficiency values for the two reexposed chemicals were then measured. A t test was used to analyze all of the respiratory physiology data whereas regression analysis was applied to the uptake efficiency vs time data. The extraction efficiency of test chemical was determined to be very low (approximately 7%), indicating that this chemical is not bioconcentratedin aquatic organisms.

Additional information

Bioaccumulation: aquatic / sediment

Various experimental studies for the test chemical and supporting study for its structurally and functionally similar read across substance were reviewed for the bioaccumulation end point which are summarized as below:

 

In an experimental key study from peer reviewed journal (J. MCKIM, et. al., 1985), handbook and secondary source, bioaccumulation experiment in Salmon gairdneri (rainbow trout) was conducted for determining the BCF (bioaccumulation factor) value of test chemical. Salmon gairdneri (rainbow trout) was used as a test organisms for the study. BCF value of test chemical was measured using a logKow value of 0.23. The study was performed at a temperature of 12°C for 2-6 hrs. Radiolabeled test chemical was used for the study.All radiolabeled chemicals (purity > 98%) used in these experiments were supplied by Pathfinder Laboratories. Specific activities were confirmed by liquid scintillation counting (LSC) then gas chromatographic (GC). Analyses were done on a Hewlett-Packard 5730A automatic CC with Model 3552A data system. Test chemical was chromatographed on a Tenax-CC 60/80 mesh 3-ft X 2-mm column after direct aqueous injection. Rainbow Trout used in the study weighed 660 to 840 g. Fishes were fed with Glencoe mills trout feed for upto 24 hr before experimentation. The fish were on a 12-hr photoperiod (incandescent) at an intensity of 11.0 Ix at the air-water interface. All of the trout were acclimated to a temperature of 1 I to 12°C for several months prior to experimental use. Plexiglass respirometer metabolism chamber was used as a test vessel for the study. Chemicals were individually introduced into the respirometer-metabolism chambers at water concentrations 10 to 100 times lower than reported 96-hr LC50 values and lower than solubility value. The duration of exposure to each chemical was 2 to 6 hr during which the inspired and expired water of each fish was monitored three to six times to determine the amount of each chemical removed by a fish after flowing once across its gills (extraction efficiency). At the end of each 3- to 6-hr period, chemical dosing was stopped and the chambers were flushed with control water for 1 hr followed by initiation of dosing with the next chemical to be tested. Two separate experiments were conducted utilizing two fish per experiment. Two fish out of the four were reexposed with selected chemical near the end of each 2 to 4 day experiment to see if changes in uptake efficiency has occurred for a given chemical over the duration of the experiment. Uptake efficiency values for the two reexposed chemicals were then measured. A t test was used to analyze all of the respiratory physiology data whereas regression analysis was applied to the uptake efficiency vs time data. The extraction efficiency of test chemical was determined to be very low (approximately 7%), indicating that this chemical is not bioconcentratedin aquatic organisms.

 

In a supporting study, bioaccumulation experiment in rainbow trout was conducted for 1 hr for determining the BCF (bioaccumulation factor) value of test chemical (Wolfgang Larisch, et. al., 2017). Rainbow trout of an average weight of 750 g was used as a test organisms for the study. BCF value of test chemical was measured using a logKow value of 0.2. Rainbow trout has a ventilation rate of 117 ml/min. The ventilated water volume that actually is in contact with the gills, the respiratory volume, is approximately 70% of the ventilation rate. The uptake efficiency is defined as the substance mass that is taken up, Nupt (mol/min) over the substance mass that is delivered into the gills by ventilation Nresp (mol/min). This leads to a natural upper limit of 70% if the respiratory volume is 70% of the ventilation rate. The extraction efficiency of test chemical was determined to be very low (approximately 5%), indicating that this chemical is not bioconcentrated in aquatic organisms.

 

Another bioaccumulation study was conducted for estimating the BCF (bioaccumulation factor) value of test chemical (authoritative databases, 2017). The bioaccumulation factor (BCF) value was calculated using a logKow of 0.23 and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of test chemical was determined to be 0.88 dimensionless, which does not exceed the bioconcentration threshold of 2000, indicating that the test chemical is considered to be non-accumulative in aquatic organisms.

 

For the test chemical fromauthoritative databases (2017),the bioaccumulation study in fish was conducted for estimating the BCF (bioaccumulation factor) value of test chemical. The bioaccumulation factor (BCF) value was calculated using a logKow of 0.88 and a regression-derived equation. The estimated BCF (bioaccumulation factor) value of test substance was determined to be 3 dimensionless, which does not exceed the bioconcentration threshold of 2000, indicating that the test chemical is considered to be non-accumulative in aquatic organisms.

 

On the basis of above overall results for test chemical, it can be concluded that the BCF value of test chemical was determined to be 0.88which does not exceed the bioconcentration threshold of 2000, indicating that the test chemicalis not expected to bioaccumulate in the food chain.