Decanoic acid, mixed esters with heptanoic acid, octanoic acid, pentaerythritol and valeric acid

Toxicity to soil macroorganisms except arthropods

Description of key information

A 14-day OECD 207 study has demonstrated that the registered substance did not have any mortality effect on  earthworms (Kelley 2013).   The acute NOEC (14 d) was ≥ 1000 mg/kg soil  dw for mortality.   In addition, a 56-day OECD 222 earthworm reproduction study has shown that the registered substance did not have any  long-term effects on mortality, body weight (growth) and reproduction in earthworms (Kelley 2014).  The chronic toxicity NOEC (56 d) ≥ 101 mg/kg dw for reproduction  and the chronic NOEC (28 d) ≥ 101 mg/kg dw for adult mortality, body weight (growth)  in Eisenia fetida.     Overall,  the registered substance is not expected to cause acute or chronic adverse effects to earthworms ( Eisenia fetida).  No PNEC for soil could be derived for quantitative risk assessment.  However, it is possible to qualitatively conclude that the registered substance does not pose an unacceptable risk to soil macro-organisms like earthworms.    

Additional information

Short-term toxicity to soil macro-organisms (e.g., earthworms)

An acute test with decanoic acid, mixed esters with heptanoic acid, octanoic acid, pentaerythritol and valeric acid (CAS No. 71010-76-9) was conducted according to OECD 207 under GLP conditions (Kelley, 2013).Eisenia fetidawas exposed to a test concentration of 1000 mg/kg dw in artificial soil for 14 days. Mortality was recorded at the end of the study. 100% survival was observed in both the control group and treatment groups resulting in a NOEC (14 d) for mortality of ≥ 1000 mg/kg dw. The 14-day EC50 value is expected to be greater than 1000 mg/kg d.w. (nominal) for mortality. Due to findings for this study, it can be concluded that the registered substance will not exhibit acute effects on soil macroorganisms. Overall, the results indicate that the registered substance is not expected to cause any acute toxicity to earthworms.

 

Long-term toxicity to soil macro-organisms (e.g., earthworms)

A long-term earthworm study (OECD 222) was carried out recently with the registered substance, decanoic acid, mixed esters with heptanoic acid, octanoic acid, pentaerythritol and valeric acid (CAS No. 71010-76-9). The results of the 56 day study indicated no long-term effects on reproduction at 101 mg/kg dw soil. The number of juveniles reproduced in the treated group (mean 67) was not statistically different from that in the control group (mean 75). Hence, the 56-day NOEC>101 mg/kg dw for reproduction). Also no long-term effects on adult worm mortality or growth were observed at Day 28. No mortality in adults was observed for the control group and the one mortality (2.5%, 1 out of 40) in the treated group was not considered statistically significant. The body weights of the control and treated adult earthworms were not statistically different . Hence, the 28-day NOEC was ≥ 101 mg/kg for mortality and body weight (growth). No abnormal or distinct changes in behavior were observed in either the control or treated groups over the course of the study. Overall, these findings indicate that the registered substance is not expected to cause long-term adverse effects or toxicity (e.g., reproduction) in the earthworm and is not expected to cause affect mortality or body weight (growth) in the earthworm (Eisenia fetida).

 

Therefore, the 56-day reproduction NOEC value is >101 mg/kg d.w (nominal) and 56-day EL50 is expected to be greater than 101 mg/kg (nominal). The 28-day adult worm mortality and body weight (growth) NOEC and EL50 values for Eisenia fetida are expected to be equal to or greater than 101 mg/kg.

 

The following information is taken into account for effects on soil macro-organisms except arthropods for the derivation of PNEC

The registered substance did not have long-term effects on terrestrial earthworm mortality, reproduction and growth in a 56-day OECD 222 chronic reproduction toxicity test and did not have any acute mortality to earthworms in a 14-day OECD 207 acute toxicity test

 Acute toxicity NOEC (14 d) ≥ 1000 mg/kg dw for mortalityEisenia fetida(OECD 207)

Chronic toxicity NOEC (56 d)≥ 101 mg/kg dw for reproduction Eisenia fetida(OECD 222)

 NOEC (28 d) ≥ 101 mg/kg dw for adult mortality, body weight (growth)Eisenia fetida(OECD 222)

 

Besides not causing any acute or chronic toxicity to soil macro-organism like earthworms (Eisenia fetida), the registered substance showed no long-term adverse effects to soil microorganisms in a 28-day OECD 216 nitrogen transformation test (Carter, 2014). Furthermore, the registered substance did not have any long-term effects on the seedling emergence, growth and reproduction of two terrestrial plants,B. rapaandA. sativain 35-day and 52-day ISO 22030 chronic plant toxicity tests, respectively (Butler, 2014). Finally, results froma 28-day chronic sediment toxicity study (OECD 225) indicate that the registered substance did not cause any long term effect on mortality, growth (biomass) or reproduction (i.e., number of live worms) in the benthicLumbriculus variegatusa in sediment (Sutherland, 2014).Collectively, these findings as well as the previously discussed lack of acute and chronic aquatic toxicity provide further support that the registered substance, CAS 71010-76-9), is not likely to pose a concern to organisms in soil, sediment or aquatic compartments. The lack of soil or terrestrial toxicity is most likely attributable to the low water solubility, high log Kow (inability to cross biomembrane) and low bioavailability of the registered substance. In addition, the registered substance is readily biodegradable, rapidly metabolized and it is not persistent or bioaccumulative.     

 

As no PNEC for water could be determined (no aquatic toxicity), it is not possible to derive a PNEC for soil using the EqPM (equilibrium partitioning method). The available toxicity data indicate that the registered substance is not expected to cause any adverse effects to soil or sediment organisms. While it is not possible to derive PNECs needed for quantitative risk assessment, it is possible to qualitatively conclude based on the available short- and long-term terrestrial test data that the registered substance does not pose an unacceptable risk to soil macroorganisms like the earthworm.