Alkenes, C11-12, hydroformylation products, distn. residues

Sediment toxicity

Description of key information

Alchisor CAL 123 comprises Alkenes C11 -12, hydroformylation products, distillation residues and where environmental toxicity data exist, these are representative of the Alchisor CAL 123 substance.  In accordance with REACH Annex IX, the requirement for toxicity sediment organisms is waived on the basis of "study technically not feasible". The substance is a UVCB. It is readily biodegradabe and has low toxicity to aquatic life. No reliable predicted nor measured toxicity data to sediment organisms are available for Alchisor CAL 123.

Additional information

Alchisor CAL 123 comprises Alkenes C11-12, hydroformylation products, distillation residues and where environmental toxicity data exist, these are representative of the Alchisor CAL 123 substance. In accordance with REACH Annex X, the requirement for studies of the effects on sediment organisms is waived on the basis of "study technically not possible".It is a UVCB and standard tests for this endpoint are intended for single substances and are not appropriate for the complex substances such as UVCBs. In addition, other evidence presented in this dossier on the substance's ready biodegradability and low toxicity to aquatic organisms further support the waiver. No reliable predicted nor measured toxicity to sediment organisms data are available for Alchisor CAL 123.

Study technically not feasible

In accordance with Annex XI, section 2, the toxicity effects studies to sediment dwelling organisms (required in Section 9.5.1) do not need to be conducted as the study is technically not possible. The substance is a UVCB. Standard tests for this endpoint are intended for single substances and are not appropriate for the complex substances (UVCBs). Alchisor CAL 123 degraded 87.7% in water in 28 days. Therefore, it is technically difficult to maintain constant test substance concentration during the test period as required for this test. The rapid degradability further indicates that it is unlikely that long-term exposure will occur, via the water column, as Alchisor CAL 123 is deemed readily biodegradable. In addition, Alchisor CAL 123 has low toxicity to aquatic invertebrates (>100 mg/L based on loading rate at 50% mortality). It also has low toxicity to earth worms, with the NOEC being 1000 mg/kg dry soil, based on the numbers of juveniles produced.

Biodegradation

Alchisor CAL 123 has been shown in the reliable (Klimisch 1) study by Schaefer and Matthews (2010) to be readily biodegradable in water. The test substance biodegraded to an extent of 87.7% after 28 days and although the biodegradation rate just missed the 10-day window threshold, this aspect of the test is not applicable to mixtures where different components of the mixture can biodegrade preferentially (reference TG 103C). It is assumed that Alchisor CAL 123 will readily biodegrade in water and be unavailable for uptake by sediment organisms.

Toxicity to Aquatic Organisms

The toxicity of the test substance to aquatic organisms is very low based on the evidence presented in this dossier. The lowest measured toxicity was based on an algal test where the NOEL based on algal growth was 25 mg/L. Acute toxicity to invertebrates and fish was >100 mg/L based on loading rate at 50% mortality. Because the substance has been deemed readily biodegradable, it is unlikely that sediment organisms would encounter long-term exposure to the substance. Using this evidence, it is reasonable to assume that Alchisor CAL 123 represents a low hazard and is not considered to be toxic (in PBT terms) to aquatic life. In addition, the toxicity of Alchisor CAL 123 to earth worms is very low. The measured NOEC was 1000 mg/kg dry soil, based on the numbers of juveniles produced.

In summary, the data requirement for toxicity to sediment organisms is waived on the basis of "study technically not feasble", ready biodegradability in water and the low toxicity to aquatic organisms. For completeness, PNECs were calculated using the partitioning coefficient method. PNECsediment freshwater is 44,176 mg/kg ww (or 9,603 mg/kg dry wt) and the PNECsediment marine is 441.7 mg/kg ww (or 96 mg/kg dry wt).