Registration Dossier

Administrative data

Key value for chemical safety assessment

Additional information

Information is available on the genotoxic potential of the following members of this category:

Test substance identity

in vitro

In vivo

Bacterial mutation

Mammalian cell mutation

Mammalian cell cytogenetics

Other mammalian cell test

 

Hex-1-ene

v

v

v

v

v

Alkenes, C6-

v

 

 

 

v

Alkenes, C6-8

v

 

 

 

 

Alkenes, C6-8, branched, C7 rich

v

 

 

 

v

Oct-1-ene

v

 

v

v

 

Alkenes, C8-10, branched, C9 rich

v

 

 

 

v

Alkenes, C10/11/12/13

v

 

v

 

 

Alkenes C11/13/14

v

 

v

 

 

Dodec-1-ene

v

 

v

 

 

Octadec-1-ene

v

 

v

 

 

Alkenes, 20-24 branched and linear

v

 

v

 

v

Alkenes, 24-28

v

 

 

 

 

Details of these studies are summarised below.

Genetic Toxicity in Bacteria in vitro:

Information is available from two studies that have investigated the in vitro bacterial genetic toxicity potential of 1-hexene.

In the first investigation (Jones, 1990), strains TA 98, TA 100, TA 1535, TA 1537, and TA 1538 of S. typhimurium were exposed to 1-hexene in DMSO at concentrations of 1.5, 5, 15, 50, 150, or 500 ug/plate in the presence and absence of mammalian metabolic activation using the plate-incorporation method. 1 -Hexene was tested up to cytotoxic concentrations (5000 ug/plate) in a preliminary range-finding study and based on the results, the above mentioned concentrations were used in the mutagenicity study. No substantial increases in revertant colony numbers of any of the five tester strains were observed at any dose level, either in the presence or absence of metabolic activation. There was no evidence of induced mutant colonies over background or a concentration related positive response observed during the study. The positive controls induced the

appropriate responses in the corresponding strains. 

In the second study (Sawin, 1982), strains TA 98, TA 100, TA 1535, TA 1537, and TA 1538 of S. typhimurium were exposed to 1-hexene (Neodene 6) in ethanol at concentrations of 0.002; 0.005; 0.01; 0.02; 0.05; 0.1; 0.2; 0.5 mg/plate in the presence and absence of mammalian metabolic activation using the preincubation plate-incorporation method. Toxicity was observed in all tester strains at the 0.5 mg/plate dose level in the presence and absence of metabolic activation. No substantial increases in revertant colony numbers of any of the five tester strains were observed subsequent to treatment with 1-hexene at any dose level, either in the presence or absence of metabolic activation. There was no evidence of induced mutant colonies over background or a concentration related positive response observed during the study. The positive controls induced the appropriate responses in the corresponding strains. 

Information is available from one study that has investigated the in vitro bacterial genetic toxicity potential of Alkenes, C6.

In this study (Przygoda, 1991), the mutagenic potential of Alkenes-C6 (MRD-91-937) was tested in five Salmonella tester strains. A toxicity pretest was conducted prior to the main mutagenicity assay to determine the highest dose of the compound that could be used in the main assay. Based on the outcome of this toxicity pretest, 320 ug/plate was selected as the high dose for use in the main study both in the presence and absence of S9. 2-Aminoanthracene (2AA), 2-nitroflourene (2NF), 9-aminoacridine (9AA), and n-methyl- n-nitro-n-nitrosoguanidine (MNNG) served as positive controls. On the day of the assay, top agar, tester strains, test or control material and S9 mix or saline were combined and poured into a plate containing a layer of agar. These plates were incubated for 2 days at 37?C. Following the incubation period, all the plates were evaluated for toxic effects and were read either manually or using an automatic colony counter. The mutagenicity assay indicated that the test chemical did not exhibit a positive dose related increase in the number of revertants in any of the tester strains used. Toxicity in the form of reduction in the number of revertant colonies or reduction in the background lawn was observed in all five strain tested. The replicate analysis performed to confirm the data observed in the first analysis did not show any deviation in the results. Based on these results it was concluded that the 1-hexene was not mutagenic to the five Salmonella strains used in the assay up to and including the highest dose of 320 ug/plate.

Information is available from one study that has investigated the in vitro bacterial genetic toxicity potential of Alkenes, C6-8.

In this investigation (May, 1995), Alkenes, C6-8 (Shop IO C6-8) was initially tested to determine its potential to cause cytotoxicity. Based on the outcome of this experiment, the main mutagenicity study was conducted in S. typhimurium strains, TA1537, TA1535, TA100 and TA98 using 50, 158, 500, 1580, or 5000 ug/plate both in the presence and absence of S9. This test was conducted in triplicate. After a 2 day incubation period, number of revertant colonies was counted, either manually or with an automated colony counter. Growth of the background lawn of non-revertant cells on minimal plates was also verified. Results obtained with all strains were confirmed in a second, independent experiment. The preliminary toxicity test did not cause any visible thinning of the background lawn of non-revertant cells as a result of exposure to Shop IO C6 -8. Positive controls indicated that the test system was working appropriately. In the main mutagenicity test, no increase in revertant colony numbers over control were obtained with any of the four tester strains exposed to Shop IO C6-8 at concentrations ranging from 50 to 5000 ug/plate. Based on these results, Alkenes, C6-8 was not mutagenic in the presence or absence of S9. 

Information is available from one study that has investigated the in vitro bacterial genetic toxicity potential of Alkenes, C6-8 branched, C7 rich.

In this study (May, 1995), Alkenes, C6-8 branched, C7 rich (Shop IO C6-8) was initially tested to determine its potential to cause cytotoxicity. Based on the outcome of this experiment, the main mutagenicity study was conducted on S. typhimurium strains, TA1537, TA1535, TA100 and TA98 using 50, 158, 500, 1580, or 5000 ug/plate both in the presence and absence of S9. This test was conducted in triplicate. After a 2 day incubation period, the number of revertant colonies was counted, either manually or with an automated colony counter. Growth of the background lawn of non-revertant cells on minimal plates was also verified. Results obtained with all strains were confirmed in a second, independent experiment. The preliminary toxicity test did not cause any visible thinning of the background lawn of non-revertant cells. Positive controls indicated that the test

system was working appropriately. In the main mutagenicity test, no increase in revertant colony numbers over control were obtained with any of the four tester strains exposed to Alkenes, C6-8 branched, C7 rich at concentrations ranging from 50 to 5000 ug/plate. Based on these results, Alkenes, C6-8 branched, C7 rich was not mutagenic in the presence or absence of S9. 

Information is available from one study that has investigated the in vitro bacterial genetic toxicity potential of 1-octene.

In this investigation (Glueck, 1983), tester strains TA98, TA100, TA1535, TA1537, and TA1538 of S. typhimurium were exposed to 1-octene (Neodene 8 Alpha Olefin) in ethanol at concentrations of 1.4 x 10-4, 4.5 x 10-4, 1.4 x 10-3, 4.5 x 10-3, 1.4 x 10-2, 4.5 x 10-2, 0.14, 0.45 mg/plate in the presence and absence of mammalian metabolic activation using a pre-incubation method. In a preliminary cytotoxicity screen, effects were observed at 0.45 mg/plate in the absence of metabolic activation and at 4.5 and 0.45 mg/plate in the presence of metabolic activation. In the mutagenicity assay, toxicity occurred at 0.45, 0.14 and 0.045 mg/plate in the absence and presence of metabolic activation with all the bacterial strains tested. A positive response (>2.5 times the background) for the number of revertant mutant colonies was observed for all positive controls tested in the presence and absence of metabolic activation. There was no evidence of a concentration related positive response of induced mutant colonies over background for the test material at any concentration tested. 1-Octene was not mutagenic in the presence or absence of S9. 

Information is available from one study that has investigated the in vitro bacterial genetic toxicity potential of Alkenes, C8-10 branched, C9 rich.

In this study (Przygoda, 1991), a toxicity pretest was conducted prior to the main mutagenicity test using 1 to 10,000 ug test substance /plate and Salmonella strain TA98 using a single plate per dose level. Colony counts were made after a 2 day incubation period and plates were evaluated for toxic response. In the main study, S. typhimurium tester strains TA98, TA100, TA1535, TA1537, and TA1538 were exposed to Alkenes, C8-10 branched, C9 rich (MRD-91-938 nonene) in ethanol prior at doses of 10, 32, 100, 320 and 1000 ug/plate. On the day of dosing, molten top agar, the five tester strains and the test and control materials (vehicle) and the S9 mix or saline were combined and the mix was poured into a plate consisting of a minimum layer of agar. Once cooled, the plates were inverted and incubated for 2 days at 37 degrees Centigrade. After incubation, all plates were evaluated for toxic effects and were read either manually or with an automatic colony counter. Ttoxicity in the form of either reduced number of revertant colonies or as reduced background lawn was noted in all five tester strains in the main study. A repeat assay performed to verify findings from the first assay showed similar results. All positive controls (2AA, 9AA, MNNG, and 2NF) responded appropriately. Vehicle control plates also showed an appropriate response. These results indicate that Alkenes, C8-10 branched, C9 rich is not mutagenic to the five Salmonella tester strains at doses up to and including 1000 ug/plate.

Information is available from two studies that have investigated the in vitro bacterial genetic toxicity potential of Alkenes, C10/11/12/13.

In the first study (Brooks, 1983), separate assays were used to determine the mutagenic potential of Alkenes, C10/11/12/13 (Olefin 103 PQ/11) in S. typhimurium (strains, TA1537, TA1535, TA100 and TA98), E. coli (strain WP2 uvrA) and S. cerevisiae (JDI). Mutagenicity testing in both bacterial strain was performed in the presence and absence of rat liver fraction S9 at 31.25, 62.5, 125, 250, 500, 1000, 2000 or 4000 ug per plate. The cultures were incubated at 37 C for 48-72 hours before the revertant bacterial colonies were counted. Testing in S. cerevisiaeI used test concentrations of 0.01, 0.1., 0.5, 1.0 or 2.0 mg/mL, both in the presence and in the absence of rat liver S9 fraction. After 18 hours incubation at 30 C in the absence of S9 fraction, or 2hours at 37 C followed by 16 hours at 30 C in the presence of S9 fraction, the cultures were seeded onto the

appropriate culture media for the selection of prototrophic colonies. After 3 days incubation at 30 C, the numbers of prototrophic yeaset colonies were counted. Alkenes, C10/11/12/13 did not cause an increase in the reverse mutation rates in bacteria or in the mutation gene conversion rates in yeast in the presence or absence of metabolic activation. The cell survival in yeast was decreased in relation to dose in the absence of S9. Cell survival was relatively unaffected in the presence of S9. Positive controls indicated that the test systems were working appropriately. 

In the second bacterial reverse gene mutation assay on Alkenes, C10/11/12/13 (Brooks, 1982), five strains of S. typhimurium and 2 strains of E. coli were exposed to test substance in acetone at concentrations of 31.25, 62.5, 125, 250, 500, 1000, 2000, or 4000 ug/plate in the presence or absence of rat liver S9 fraction using a plate incorporation assay and a 48 hour incubation period. The test conditions appear to generally comply with OECD 471 guideline requirements with some limitations. Positive controls provided an appropriate response. Although there were occasional increases in the reverse mutation rates in bacteria, the results were slight, were not reproducible, and were not dose dependent. Alkenes, C10/11/12/13 did not alter reverse mutation rates in the presence or absence of S9 activation. 

Information is available from two studies that have investigated the in vitro bacterial genetic toxicity potential of Alkenes, C11/13/14.

In the first test (May, 1996), four strains of S. typhimurium (TA 98, 100, 1535, and 1537) were exposed to Alkenes, C11/13/14 (SHOP internal olefins C134) dissolved in ethanol at concentrations of 50, 158, 500, 1580, and 5000 ug/plate in the presence and absence of mammalian S-9 metabolic activation using a plate incorporation assay and incubated for 2 days. An appropriate preliminary toxicity assay was performed to select an adequate dose range for testing in the mutagenicity assay. The test conditions appear to comply with OECD 471 guideline requirements.  Positive and negative controls indicated that the test system was working appropriately. None of the test chemical treated bacterial strains

showed increases in reversions. Based on these results, the study authors concluded that Alkenes, C11/13/14 was not mutagenic to the four tester strains treated with concentrations up to 5000 ug/plate either in the presence or absence of S9. 

In the second study (Brooks, 1982; procedure as described above), five strains of S. typhiumurium and 2 strains of E. coli were exposed to Alkenes, C11/13/14 (olefin 13/14) in acetone at concentrations of 31.25, 62.5, 125, 250, 500, 1000, 2000, or 4000 ug/plate in the presence or absence of rat. The positive controls provided an appropriate response.  Alkenes, C11/13/14 did not alter reverse mutation rates in the presence or absence of S9 activation. 

Information is available from one study that investigated the in vitro bacterial genetic toxicity potential of 1-dodecene.

In this study (Dean, 1980), five strains of S. typhimurium (TA98, TA100, TA1535, TA1537, and TA1538) and 2 strains of E. coli (WP2 and WP2uvrA) were exposed to 1-dodecene (alpha C12) in acetone at concentrations of 0, 0.2, 2, 20, 200, or 2000 ug/plate in the presence and absence of mammalian metabolic activation using a plate-incorporation method. No increase in reverse mutation rate was noted in either assay in the presence or absence of metabolic activation. A preliminary study to assess bacterial cytotoxicity to determine appropriate doses was not performed.

Information is available from one study that investigated the in vitro bacterial genetic toxicity potential of 1-octadecene.

In this investigation (Dean, 1980), five strains of S. typhimurium (TA98, TA100, TA1535, TA1537, and TA1538) and 2 strains of E. coli (WP2 and WP2uvrA) were exposed to 1- octadecene (alpha C18) in acetone at concentrations of 0, 0.2, 2, 20, 200, or 2000 ug/plate in the presence and absence of mammalian metabolic activation using a plate- incorporation method. No increase in reverse mutation rate was noted in either assay in the presence or absence of metabolic activation. A preliminary study to assess bacterial cytotoxicity to determine appropriate doses was not performed.

Information is available from two studies that have investigated the in vitro bacterial genetic toxicity potential of Alkenes, C20-24, branched and linear.

In the first test (Thompson, 1998), strains (TA1535, TA1537, TA98, and TA100) of S. typhimurium and one strain (WP2 uvrA’) of E. coli were exposed to Alkenes C20-24, branched and linear, in acetone at concentrations of 0, 15, 50, 150, 500, 1500, and a limit concentration of 5000 ug/plate in the presence and absence of mammalian metabolic activation using the plate-incorporation method. No evidence of an increase in revertants was noted. The positive controls induced the appropriate responses in the corresponding strains.

In the second test (Thompson, 2000), S. typhimurium tester strains TA1535, TA1537, TA98, TA100, and TA 102 were exposed to Alkenes C20-24, branched and linear, in acetone at concentrations of 0, 15, 50, 150, 500, 1500, and 5000 ug/plate in the presence and absence of mammalian metabolic activation again using a plate-incorporation method. Again a limit concentration was used as the top treatment level. There was no increase in revertant numbers, and a satisfactory response was obtained with the positive control substances.

Information is available from one study that has investigated the in vitro bacterial genetic toxicity potential of Alkenes, C24-28.

In this investigation (Thompson, 1998), strains TA1535, TA1537, TA98, and TA100 of S. typhimurium and strain WP2uvrA of E. coli were exposed to Alkenes, C24-28 (C24-C30, branched and linear) at concentrations of 0, 15, 50, 150, 500, 1500, or 5000 ug/plate using the direct plate incorporation method. The test conditions complied with the guideline requirements for this study type. In a preliminary range finding toxicity test, there was no reduction of the background lawn at any dose level (tested up to 5000 ug/plate); therefore, the test material was tested at this limit dose (i.e., 5000 ug/plate). The study authors reported that there were no significant increases in the frequency of revertant colonies in any bacterial strain at any dose level, in the presence or absence of S9. All positive, vehicle and negative controls responded appropriately and the S9 fraction was shown to be satisfactory. Based on these test results, the authors concluded that Alkenes, C24-28 (C24-C30, branched and linear)was non-mutagenic to the bacterial strains tested in this study. 

Genetic Toxicity in Mammalian Cells in vitro:

Information is available from one study that has investigated the in vitro mammalian genetic toxicity potential of 1-hexene.

1-Hexene, diluted in DMSO, was examined in a key mouse lymphoma thymidine kinase assay using L5178Y (TK+/-) cells (Adams, 1990). Prior to the main mutation study, a preliminary study was conducted with the test chemical to determine its potential to cause cytotoxicity and also to determine an appropriate range for the main mutation study. Study protocols for both the preliminary and main study were similar with minor modification made in the main study. Based on experimental results, the study authors concluded that 1 -hexene was cytotoxic at doses above 300 ug/ml while it was not mutagenic either in the presence or absence of S9 at concentrations of 300 ug/ml and lower.

Cytogenicity in Mammalian Cells in vitro:

Information is available from two studies that have investigated the in vitro mammalian cytogenicity potential of 1-hexene.

In the first cytogenetics assay (chromosome aberration), human lymphocyte cultures were exposed to 1-hexene in DMSO at concentrations of 0, 2.0, 3.9, 7.8, 15.6, 31.3, 62.5, 125, 250, 500, 1000 ug/mL in the presence and absence of metabolic activation for 22 hours (Adams, 1990). 1 -Hexene when tested at 250, 500, or 1000 ug/mL was seen to be cytotoxic to the cells with very few live cells apparent at these dose levels. Therefore, 125 ug/mL was selected as the highest concentration for metaphase analysis with 62.5 and 15.6 ug/ml selected as the intermediate and lowest concentrations, respectively. A appropriate response was obtained with the positive controls. There was no evidence (or a concentration

related positive response) for chromosomal aberrations after 1-hexene treatment.

 

In a second chromosome aberration test, Chinese Hamster Ovary cells (CHO) were exposed to 1-hexene (Neodene 6 alpha olefin) in ethanol at concentrations of 0, 0.034, 0.06, 0.11, 0.19, 0.34, or 0.60 mg/mL (Sawin and Smith, 1983) in the presence and absence of metabolic activation for 3 hours (+S9) or 12 hours (-S9). Two separate studies were performed. In the first study, the three highest doses in the absence of S9 were toxic; no increase in aberrations was noted in the remaining concentrations. In the presence of S9, the 0.6 mg/mL concentration was toxic and an increase in aberrations was observed in the 0.06 mg/mL concentration. Toxicity at the top two doses, +S9, was also noted in the second study, but no increase in aberrations was observed. Therefore, it was concluded that 1-hexene did not induce chromosomal aberrations in CHO cells under the conditions of this study. The positive control substances (triethelene amine and cyclophosphamide) induced the appropriate response. 

Information is available from one study that has investigated the in vitro mammalian cytogenicity potential of 1-octene.

In this test (Sawin and Smith, 1983) was designed to evaluate the potential for 1-octene (Neodene-8 alpha olefin) to induce chromosome aberrations in Chinese Hamster Ovary (CHO) cells. Following a preliminary cytotoxicity assay the main study was conducted by exposing the CHO cells to 6 concentrations of 1-octene prepared in ethanol; concentrations of the test chemical ranged from, 1.0 X 10-2mg/mL to 1.0X10 -3mg/mL in 1/5 log10dilutions. Cells were exposed both, in the presence and absence of S9 fractions. The study included appropriate negative and positive controls. Concentrations of 0.072 mg/mL 1-octene and above were cytotoxic to CHO cells. In the absence of S9 no increase in aberrations was

found. In the presence of S9, the mean aberrations per cell exceeded the solvent control by 2-fold or more at the 5 highest concentrations tested while the percent abnormal cells exceeded the solvent controls by 2-fold or more at 3 nonconsecutive concentrations. The increases, however, were only slightly over 2-fold and were not concentration dependent. It was conclude that 1-octene was not clastogenic toward mammalian cells in vitro.

Information is available from one study that have investigated the in vitro mammalian cytogenicity potential of Alkenes, C10/11/12/13.

In this assay, a chromosome aberration test (Brooks, 1983), cultures of rat liver cells were exposed to Alkenes C10/11/12/13 (Olefin 103 PQ/11) for 24 hours at concentrations equivalent to 5, 10, 15, 20, 25, 30, 35, or 40 ug/mL in a preliminary cytotoxicity test. After 24 hours fresh medium was supplied and cells were plated and cultured for 5 days, then colonies containing at least 50 cells were counted. A concentration of 20 ug/mL caused a reduction of 15% in the cloning efficiency and 25 ug/mL caused a reduction of 59% in cloning efficiency; therefore, concentrations of 5, 10, 20, or 25 ug/mL were used for the main chromosomal aberration assay. The results demonstrated that Alkenes, C10/11/12/13 did not induce chromosomal damage in rat liver cells under the experimental conditions of the study.

 

Information is available from a chromosomal aberration test using olefin 11/12 and olefin 13/14. These results provide supporting information regarding the clastogenic potential of Alkenes, C10/11/12/13 and Alkenes C11/13/14.

In this study (Brooks, 1982), cultures of rat liver cells were exposed to several different olefin products including olefin 11/12 and olefin 13/14 for 24 hours. Since specifics on the study design were not provided, it cannot be determined whether the test conditions complied with OECD 473 guidelines. Preliminary cytotoxicity tests indicated that neither olefin 11/12 nor olefin 13/14 were cytotoxic at any of the concentrations tested (0.1 to 500 ug/mL). Therefore, concentrations of 125, 250, and 500 ug/mL were used to test for main cytogenicity test. The study authors concluded that both test substances were negative for chromosomal damage in rat liver cells.

Information is available from one study that has investigated the in vitro mammalian cytogenicity potential of 1-dodecene.

In this investigation, monolayer slide cultures of rat liver cells (RL1) were exposed to 1-dodecene (alpha C12) in acetone at concentrations of 0, 125, 250, 500 ug/mL for 24 hours (Dean, 1980). The highest treatment level was cytotoxic. The positive control (DMBA) induced the appropriate response. There was no evidence of consistent increase in the frequency of chromosomal damage (chromatid gaps, chromatid breaks, or total chromosomal aberrations) induced over background.

Information is available from one study that has investigated the in vitro mammalian cytogenicity potential of 1-octadecene..

In this chromosomal aberration test, monolayer slide cultures of rat liver cells (RL1) were exposed to 1-octadecene (alpha C18) in acetone at concentrations of 0, 125, 250, 500 ug/mL for 24 hours (Dean, 1980). The highest treatment level was cytotoxic.. The positive control (DMBA) induced the appropriate response. There was no evidence of consistent increase in the frequency of chromosomal damage (chromatid gaps, chromatid breaks, or total chromosomal aberrations) induced over background.

Information is available from two studies that have investigated the in vitro mammalian cytogenicity potential of Alkenes, C20-24, branched and linear.

In the first investigation, human lymphocytes (duplicate cultures) were treated with 0, 312.5, 625, 1250, 2500, or 5000 ug Alkenes, C20-24 branched and linear /mL in the presence and absence of metabolic activation (Wright, 1998). Two independent experiments were conducted with different exposure and harvest times: Experiment (1) 4 hour exposure followed by 16-hours for a total of 20 hour harvest time, ±S9; and Experiment (2) 20 hour exposure, -S9, or 4-hour exposure,+S9, followed by 16-hours for a total of 20 hour harvest time. Additionally, vehicle (acetone) and positive controls were included in the study design. Treatment with Alkenes, C20-24 did not result in any statistically significant increase in the frequency of cells with chromosome aberrations. The number of cells with chromosome aberrations in the vehicle control was found to be within the normal range, and the positive controls responded appropriately.

 

In the second chromosomal aberration test on Alkenes, C20-24 branched and linear, human lymphocytes (duplicate cultures) were exposed to 0, 3, 6, 12, 24, 48, 96 ug/mL in the presence and absence of metabolic activation (Pickard, 2008). Two independent experiments were conducted with different exposure and harvest times: Experiment 1) 4 hour exposure followed by 20 -hour culture in treatment time, ±S9; and Experiment 2) 24 -hour exposure, -S9, or 4-hour exposure,+S9, followed by 20 hour culture in treatment time. Additionally, vehicle (acetone) and positive controls were also utilized in the study design. Treatment with the test substance did not result in any statistically significant increase in the frequency of cells with chromosome aberrations. The number of cells with chromosome aberrations in the vehicle control was found to be within the normal range, and the positive controls responded appropriately. Under the conditions of this study, C20-C24 Alkenes, branched and linear are considered to be non-clastogenic to human lymphocytes in vitro.

Other Studies in vitro:

Additional information is available from other studies that have investigated the in vitro genotoxic potential of 1-hexene.

In one study (Goode, 1983), 1-hexene (Gulftene 6) was assessed using the BALB/3T3 cell transformation test. In a preliminary assay, cytotoxicity (measured as percent relative survival) in BALB/3T3 cells increased in a dose-dependent manner, with percent relative survival rates of 67.6%, 54.8%, 24.1%, and 4% at 1-hexene concentrations of 32, 1024, 2048, and 5000 ug/mL, respectively. In the main transformation assay, the relative cloning efficiency at the highest dose tested (2048 ug/mL) was 57.9% indicating toxicity to the BALB/3T3 cells. Raw transformation data for Type III foci was 3 for medium control; 4 for the vehicle control; 3 for 1-hexene at 256 ug/mL; 3 at 512 ug/mL; 1 at 1024 ug/mL; and 2 at 2048 ug/mL. The raw transformation data (Type III foci) for the positive control (3 -methylcholanthrene) was 27. Under the conditions of this BALB/3T3 transformation

assay, 1-hexene was negative for cell transformation.

In another study (Goode, 1984), unscheduled DNA synthesis was investigated in primary hepatocytes treated with 1-hexene (Gulftene 6). The mean net nuclear grain count (standard deviation) for the vehicle control was 0.92 (0.93) compared to counts of 5.89 (6.16) and 3.48 (6.02) for 500 and 2000 ug/mL 1-hexene, respectively. Based on the study authors criteria (exceeded the control by 6 grains per nucleus), 1-hexene did not elicit unscheduled DNA synthesis in mammalian hepatocytes.

Additional information is available from other studies that have investigated the in vitro genotoxic potential of 1-octene.

1-Octene (Neodene 8 alpha olefin) diluted in ethanol was investigated using the BALB/3T3 cell transformation test (Rundell, 1983). Preliminary studies indicated that the test substance was cytotoxic to the cells so concentrations of 16, 32, 40, 50, and 62.5 ug/mL without S9, and 63, 125, 250, 500, and 1000 ug/mL in the presence of S9, were used for the transformation assay. 1-octene did not increase the transformation frequency of Balb/c-3T3 cells ± S9.

In another cell transformation test (Rivedal, 1992) 1-octene (> 99% pure) tested negative BALB/3T3 cells when exposed to concentrations ranging from 0.01 to 0.3 millimolar. The positive control substance (B(a)P) exhibited an appropriate response.

Genetic Toxicity in vivo

Information is available from one study that investigated the in vivo genotoxic potential of 1-hexene in the mouse bone marrow micronucleus assay.

In this investigation (Harnois, 1983), 5 Crl:CDR-1 (ICR) BR Swiss mice/sex/dose were treated (whole body, inhalation exposure) with 1-hexene (Gulftene 6) at doses of 0; 1000; 10,000; or 25,000 parts per million for a period of 2 hours on two consecutive days. Bone marrow cells were harvested post sacrifice on either day 3 or 4 of the study period. Animals in the negative control group were exposed to clean, filtered air alone while animals in the positive control group were treated with 75 mg/kg cyclophosphamide by i.p.injection. Lethargy and rapid respiration were observed in animals treated at 10,000 and 25,000 parts per million but these clinical effects were reversible post- exposure. 50 percent of the female mice exhibited statistically lower mean body weights on days 1 and 3. However, mean body weights of the remaining female mice were observed to

be normal when compared to corresponding control animals. No significant increase in the frequency of micronucleated polychromatic erythrocytes in the bone marrow was noted after treatment at any dose level. Male and female animals induced with cyclophosphamide exhibited a statistically higher frequency of micronucleated polychromatic erythrocytes in the bone marrow when compared with negative controls.

Information is available from two studies that investigated the in vivo genotoxic toxicity potential of Alkenes, C6.

In the first investigation, a micronucleus assay (Przygoda, 1991), five male and five female B6C3F1 mice were exposed nose only for six hours/day for ten consecutive days to 1000 ppm of Alkenes, C6 (MRD 92-321 C6 alkene) in air. The positive control, cyclophosphamide in water, was administered via oral gavage at a dose of 40 mg/kg, while air served as the negative control. Bone marrow samples were collected at approximately 24 hours after the last exposure and evaluated for micronucleus formation. MRD 92-321 did not induce a statistically significant decrease in the mean percent of polychromatic erythrocytes which is a measure of bone marrow toxicity. The test material also did not induce a

statistically significant increase in the mean number of micronucleated polychromatic erythrocytes. The positive and negative control gave appropriate results. In a second in vivo micronucleus assay on Alkenes, C6 (Przygoda, 1991), groups of five male and five female B6C3F1 mice received a single gavage treatment of test substance (MRD-91-937) administered in corn oil at 0, 1.25, 2.5, or 5.0 g/kg body weight. The test animals were sacrificed at 24, 48, or 72 hours post dosing. The positive control, cyclophosphamide, was administered by intraperitoneal injection as a single dose and the animals sacrificed 24 hours post dosing. All animals were examined at least once daily for signs of overt toxicity. At the end of study termination, bone marrow was collected and 1000 polychromatic erythrocytes (PCE) were examined for the presence of micronuclei.

In addition, the ratio of PCEs to normochromic erythrocytes (NCEs) was determined for each animal by counting 1000 erythrocytes (PCEs and NCEs). Cyclophosphamide treatment induced a statistically significant increase in the mean number of micronucleated polychromatic erythrocytes. In treated animals, the mean number of PCEs did not differ from that or the corn oil controls however the mean number of micronucleated PCEs was significantly increased at the 5.0 g/kg body weight.

Information is available from one study that investigated the in vivo genetic toxicity potential of Alkenes, C6-8 branched, C7 rich.

In this investigation (Przygoda, 1993), B6C3F1 mice received Alkenes C6-8 branched, C7 rich (heptanes) at doses of 1.25, 2.5, and 5.0 g/kg body weight p.o. Other aspects of the study resemble those of the oral gavage investigation reported above for this author. The test material did not significantly alter the mean percent of PCEs nor was the mean number of micronucleated PCEs increased in the treated mice at any time point. Both positive and negative controls for the assay responded in an appropriate manner. Information is available from one study that investigated the in vivo genetic toxicity potential of Alkenes, C8-10 branched, C9 rich.

In this study (Przygoda, 1991), which followed the design of the oral gavage investigation discussed above, male and female B6C3F1 mice received 1.25, 2.5, or 5.0 g/kg body weight of the test material dissolved in corn oil. Cyclophosphamide, the positive control, showed an appropriate response by inducing a statistically significant increase in the mean number of micronucleated PCEs however this parameter was unchanged in animals given Alkenes, C8-10 branched, C9 rich despite a reduction in the mean percent of PCEs in the test group at the 5.0 g/kg dose.

Information is available from one study that has investigated the in vivo genetic toxicity potential of Alkenes, C20-24.

In this investigation (Durward, 1998), following a dose-range finding test, male Crl:CD-1TM(1CR)BR mice were administered C20-24 Alkenes by i.p. injection at 500, 1000, or 2000 mg/kg bodyweight and sacrificed 24 hours after treatment. A vehicle control group (arachis oil) and a positive control group (cyclophosphamide) were also included in the study. Another group of males given vehicle or 2000 mg/kg body weight test substance were at 48 hours. There were no signs of clinical toxicity or mortality in treated mice, and the number of micronucleated PCEs and the PCE/NCE ratio was not changed at any treatment level.


Justification for selection of genetic toxicity endpoint
Genotoxicity testing has been conducted on 12 members of this category ranging from C6 to C24-28. This includes 16 bacterial mutation asssays (covering C6 to C2428), one mammalian cell mutation test (C6), 9 mammalian cell cytogenetics assays (covering C6 to C20-24), 4 miscellaneous in vitro tests (UDS and cell transformation, covering C6 and C8) and 6 in vivo micronucleus assays (covering C6 to C20-24). These results of these studies demonstrate that higher olefins are not genotoxic in vitro or in vivo.

Short description of key information:
Not genotoxic in bacterial and mammalian cells in vitro or in mice following testing in vivo.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Genotoxicity testing has been conducted on 12 members of this category, ranging from C6 to C24 -28. This includes investigations performed using bacterial and mammalian cells in vitro together with testing in vivo. There was no evidence of mutagenicity or genotoxicity in any of these studies, and no classification is necessary according to the CLP regulation.