3,3-dimethyl-8,9-dinorbornan-2-one

Endpoint summary

Description of key information

Adsorption / desorption

Adsorption study was conducted at a temperature of 20°C for evaluating the adsorption capacity of test chemical Disodium 3,3-Dimethyl-8,9-dinorbornan-2-one (CAS no. 1195-79-5) onto soil (S. R. Hutchins, et. al; 1983). Initial concentration of the test chemical used for the study was0.068 µg/l. To minimize adsorptive and leaching effects, the entire column system was constructed of Teflon and glass. Four columns were constructed of 122 cmx7cm i.d. Pyrex tubing and equipped with Teflon stopcocks. The columns were then silyated, cleaned with methanol and methylene chloride and heated at 4OOOC for a period of 2 h. The columns were packed in the following manner:A0.3-g plug of silyated glass wool was inserted above the stopcock, followed by 150 g of Teflon boiling chips (Chemplast) that had been cleaned by Soxhlet extraction with methylene chloride. A final plugof5.0g silyated glass wool was placed on top of the Teflon boiling chips. Topsoil was obtained from one of the basins at the field site. The soil was packed in its natural state (8.8% moisture content) without sieving.Rocks, organic debris and soil aggregates>3.5 cm in diameter were discarded. The columns were packed, using glass rods, by stepwise addition of 1.0-cm increments of soil. The soil was distributed gently across the cross-sectional area, with care taken to minimize breakage of soil aggregates. Packing continued until a soil core length of 107 cm was obtained. The effluent ends of the columns were then fitted with Teflon Chemfluor connectors (Chemplast) and %-inch(5mm) Teflon tubing and connected to reservoirs containing a known amount of resin-extracted (RE) water. Thecolumns were saturated in an upward direction by gravity feed in step increments of 5.0 cm every 12 h.The columns were connected to feedreservoirs and operated via a Mariotte siphon to maintain a constant head of 3 cm on the soil. Feed reservoirs were constructed from 4-liter amber glass jugs and sealed with Teflon caps. Columns were then wrapped with aluminum foil to prevent light entry and algal growth. The ambient temperature of the incubator was adjusted to 2O°C. Connections were made to deliver feed solution to the reservoirs by gravity from a storage reservoir maintained at 4°C. Infiltration rates for the columns varied from 56 to 78 cm/week.Once effluent began eluting from the columns, flow rate was restricted to 1.2 to 1.7 ml/min with the effluent needle valve. At the end of the 2-d flooding period, the siphon was broken and columns were allowed to drain at normal speed. Effluent was collected to measure the total eluted volume. After feed solution had drained to the top of the soil, sterile air flow was initiated to the column headspace at 15 to 20 cm3/min to produce air. Air was maintained on the columns during the entire drying period and disconnected just before the next inundation cycle. Sampling for trace organics occurred from the time of the first appearance of column eluate to the point at which the siphon feed to the columns was disconnected. Soil columns were maintained through eight inundation cycles. During the seventh and eighth inundation cycles, mercuric chloride was added as a biocide to the feed solution for two of the columns.Trace organics were concentrated and analyzed by a modification of the resin extraction method. The extract was further concentrated to 100-p 1 by nitrogen gas. AI00-µlsyringe was used to adjust the final volume and transfer the extract to storage vials with Teflon-lined septa. Samples were initially analyzed on a Tracor 560 gas chromatograph using capillary columns with flame ionization detectors. Operating parameters were as follows: injection port temperature, 270°C; detector temperature, 300°C; oven temperature, 50°C for 4 min, programmed to 27O°C at 8°C/min. An SP2 100 fused-silica column, 50 m in length, was used with a flow rate of 1 .0ml/min for capillary work. Identification and quantitation by reverse ion search was done using a Finnigan 4000 gas chromatograph/mass spectrometer. Quantitation was done by internal and external standards, using both the base ion intensity and peak area generated in the reconstructed ion chromatogram.As the initial concentration of the chemical was 0.068 µg/l and the recovery of test material 3,3-Dimethyl-8,9-dinorbornan-2-one was determined to be 0.059± 0.012 µg/l. Thus, based on this, chemical 3,3-Dimethyl-8,9-dinorbornan-2-one can be considered to have negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

Additional information

Adsorption / desorption

Experimental study and predicted data for the target compound 3,3-Dimethyl-8,9-dinorbornan-2-one (CAS No. 1195-79-5) and supporting study for its structurally similar read across substance were reviewed for the adsorption end point which are summarized as below:

 

In an experimental key study from peer reviewed journal (S. R. Hutchins, et. al; 1983),adsorption study was conducted at a temperature of 20°C for evaluating the adsorption capacity of test chemical Disodium 3,3-Dimethyl-8,9-dinorbornan-2-one (CAS no. 1195-79-5) onto soil. Initial concentration of the test chemical used for the study was0.068 µg/l. To minimize adsorptive and leaching effects, the entire column system was constructed of Teflon and glass. Four columns were constructed of 122 cmx7cm i.d. Pyrex tubing and equipped with Teflon stopcocks. The columns were then silyated, cleaned with methanol and methylene chloride and heated at 4OOOC for a period of 2 h. The columns were packed in the following manner: A 0.3-g plug of silyated glass wool was inserted above the stopcock, followed by 150 g of Teflon boiling chips (Chemplast) that had been cleaned by Soxhlet extraction with methylene chloride. A final plugof5.0g silyated glass wool was placed on top of the Teflon boiling chips. Topsoil was obtained from one of the basins at the field site. The soil was packed in its natural state (8.8% moisture content) without sieving. Rocks, organic debris and soil aggregates>3.5 cm in diameter were discarded. The columns were packed, using glass rods, by stepwise addition of 1.0-cm increments of soil. The soil was distributed gently across the cross-sectional area, with care taken to minimize breakage of soil aggregates. Packing continued until a soil core length of 107 cm was obtained. The effluent ends of the columns were then fitted with Teflon Chemfluor connectors (Chemplast) and %-inch(5mm) Teflon tubing and connected to reservoirs containing a known amount of resin-extracted (RE) water. The columns were saturated in an upward direction by gravity feed in step increments of 5.0 cm every 12 h. The columns were connected to feedreservoirs and operated via a Mariotte siphon to maintain a constant head of 3 cm on the soil. Feed reservoirs were constructed from 4-liter amber glass jugs and sealed with Teflon caps. Columns were then wrapped with aluminum foil to prevent light entry and algal growth. The ambient temperature of the incubator was adjusted to 2O°C. Connections were made to deliver feed solution to the reservoirs by gravity from a storage reservoir maintained at 4°C. Infiltration rates for the columns varied from 56 to 78 cm/week. Once effluent began eluting from the columns, flow rate was restricted to 1.2 to 1.7 ml/min with the effluent needle valve. At the end of the 2-d flooding period, the siphon was broken and columns were allowed to drain at normal speed. Effluent was collected to measure the total eluted volume. After feed solution had drained to the top of the soil, sterile air flow was initiated to the column headspace at 15 to 20 cm3/min to produce air. Air was maintained on the columns during the entire drying period and disconnected just before the next inundation cycle. Sampling for trace organics occurred from the time of the first appearance of column eluate to the point at which the siphon feed to the columns was disconnected. Soil columns were maintained through eight inundation cycles. During the seventh and eighth inundation cycles, mercuric chloride was added as a biocide to the feed solution for two of the columns. Trace organics were concentrated and analyzed by a modification of the resin extraction method. The extract was further concentrated to 100-p 1 by nitrogen gas. AI00-µlsyringe was used to adjust the final volume and transfer the extract to storage vials with Teflon-lined septa. Samples were initially analyzed on a Tracor 560 gas chromatograph using capillary columns with flame ionization detectors. Operating parameters were as follows: injection port temperature, 270°C; detector temperature, 300°C; oven temperature, 50°C for 4 min, programmed to 27O°C at 8°C/min. An SP2 100 fused-silica column, 50 m in length, was used with a flow rate of 1 .0ml/min for capillary work. Identification and quantitation by reverse ion search was done using a Finnigan 4000 gas chromatograph/mass spectrometer. Quantitation was done by internal and external standards, using both the base ion intensity and peak area generated in the reconstructed ion chromatogram. As the initial concentration of the chemical was 0.068 µg/l and the recovery of test material 3,3-Dimethyl-8,9-dinorbornan-2-one was determined to be 0.059± 0.012 µg/l. Thus, based on this, chemical 3,3-Dimethyl-8,9-dinorbornan-2-one can be considered to have negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

 

In a prediction done using theKOCWIN Program(v2.00) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the soil adsorption coefficient i.e Koc value of test chemical 3,3 -Dimethyl-8,9 -dinorbornan-2 -one (CAS No. 1195 -79 -5). The soil adsorption coefficient i.e Koc value of 3,3 -Dimethyl-8,9 -dinorbornan-2 -one was estimated to be 114.8 L/kg (log Koc= 2.0601) by means of MCI method (at 25 deg C). This Koc value indicates that the substance 3,3-Dimethyl-8,9-dinorbornan-2-one has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

In a supporting study from authoritative database (HSDB, 2017) for the read across chemical (1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (CAS no. 76-22-2),adsorption experiment was conducted for estimating the adsorption coefficient (Koc) value of read across chemical (1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (CAS no. 76-22-2). The adsorption coefficient (Koc) value was calculated using a structure estimation method based on molecular connectivity indices. The adsorption coefficient (Koc) value of test substance (1R,4R)-1,7,7 -trimethylbicyclo[2.2.1]heptan-2 -one was estimated to be 117 (Log Koc = 2.068). This Koc value indicates that the substance (1R,4R)-1,7,7 -trimethylbicyclo[2.2.1]heptan-2 -one has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

 

On the basis of above overall results for target chemical 3,3-Dimethyl-8,9-dinorbornan-2-one (from peer reviewed journal and EPI suite) and for its read across substance (from authoritative database HSDB, 2017), it can be concluded that thetest chemical 3,3-Dimethyl-8,9-dinorbornan-2-one has a negligible to low sorption to soil and sediment and therefore have rapid to moderate migration potential to ground water.