Pentadecan-15-olide

Sediment toxicity

Description of key information

From a read-across substance (EC Number: 422-320-3) three chronic sediment toxicity studies were performed: 
- The first following OECD Guideline 218, GLP, key study, validity 2 on Lumbriculus variegatus. 28d-EC50 (reproduction) = 630 mg/Kg dw, NOEC = 210 mg/Kg dw. 
- In a second study on chironomids following OECD Guideline 218, GLP, key study, validity 1 no EC50 was determined and no effects  were observed at the highest measured concentration of 192 mg/Kg dw. As this is not a true NOEC, the calculated NOEC of 210 mg/Kg dw is used. 
- In a third study  following ISO 10872 (2010), GLP, key study, validity 1 on reprotoxicity and growth of Caernorhabditis elegans, a 4d-NOEC / 4d-LOEC >1000 mg test item/kg sediment dry weight was determined. No effects were observed. As this is not a true NOEC, the calculated NOEC of 210 mg/Kg dw is used. 

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater sediment:

210 mg/kg sediment dw

Additional information

Three key chronic studies according to the OECD Guideline 218 and ISO 10872 (2010) with GLP standards are available conducted on a read-across substance (EC Number : 422-320-3). This supporting substance is considered adequate for read-across purposes (see Iuclid section 13 for justification)

 

The first key study (Sewell, 2003) evaluated the effect of the test substance on survival and reproduction to the sediment-dwelling oligochaete Lumbriculus variegatus. Following a range-finding study, 40 worms (4 replicates of 10 worms) were exposed to artificial sediment spiked with test material at nominal concentrations of 100, 180, 320, 560 and 1000 mg/Kg (dry weight of sediment) for a period of 28 days. The numbers of worms were recorded at the end of the test. Given the decline in measured test concentrations it was considered justifiable to calculate the results based on the mean measured test concentrations. The Day 28 EC50 (reproduction) based on mean measured test concentrations was 630 mg/Kg with 95% confidence limits of 470 - 1100 mg/Kg dw. The NOEC was 210 mg/Kg dw.

 

The second key study (Memmert, 2006) evaluated the toxic effects of the test substance on the development of sediment-dwelling larvae of the midge Chironomus riparius in water-sediment systems. Five concentrations of the test item (63, 125, 250, 500 and 1000 mg/Kg dry sediment) and 2 controls (a control and a solvent control group) were tested. The test item was spiked into the sediment and first instar larvae were subsequently introduced into the static sediment-water systems. First-instar larvae of Chironomus riparius were exposed for a period of 28 days to assess the impact on full maturation of the larvae to adult midges. Since the test substance showed the majority of degradation in the sediment between Day 0 and Day 7 of the test period, the results was based on the geometric mean value of the analytically measured concentrations in the sediment on Day 0 and 7 (192 mg/kg dw at nominal 1000 mg/kg dw). Thus, the 28-d NOEC was at least 192 mg/Kg dw and the 28-d LOEC was clearly higher than 192 mg/Kg dw as no effects were observed in this study.

The third key study (Winkelmann, 2013) evaluated the toxic effects of the test item on the development of sediment-dwelling Caernorhabditis elegans following the ISO 10872 (2010) with GLP statement. After a range finding study at 10, 100 and 1000 mg test substance/kg sediment dry weight, only the 1000 mg/kg dry sediment concentration was performed in the final study. 2 controls (a control and a solvent control group) were tested and a positive control with Benzyldimethylhexadecylammonium chloride (99.7 %) was also tested. The study was performed under a static system for 4 days. All results from the study lead to the conclusions that LOEC and NOEC (Mortality, Fertility, Reproduction, Growth) are above 1000 mg/kg sediment dry weight. No effects were observed in this study.

As the NOEC values of the second and the third key studies are not true NOEC values, the calculated NOEC of 210 mg/kg dw obtained in the first key study is used for the chemical safety assessment.