SUMILIZER GP

Sediment toxicity

Additional information

No experimental data evaluating the toxicity to sediment organisms is available for Sumilizer GP .The substance is not toxic to aquatic organisms up to the limit of water solubility and in addition, available data indicate that Sumilizer GP is not bioaccumulative. Based on the available information, toxicity to sediment organisms is not expected to be of concern.

 

Intrinsic properties, fate and bioaccumulation

Sumilizer GP exhibits a log Koc value of > 5 and is poorly water soluble (< 1 mg/L, water solubility could not be determined). The Guidance on information requirements and chemical safety assessment, Chapter R.7b (ECHA, 2017) states that once insoluble chemicals enter a standard STP, they will be extensively removed in the primary settling tank and fat trap and thus, only limited amounts will get in contact with activated sludge organisms. Nevertheless, once this contact takes place, these substances are expected to be removed from the water column to a significant degree by adsorption to sewage sludge (Guidance on information requirements and chemical safety assessment, Chapter R.7a, (ECHA, 2017). Thus, discharged concentrations of this substance (if at all) into the aqueous/sediment compartment are likely to be low.

Bioaccumulation is not expected based on an available bioaccumulation study using aquatic exposure, and the result of QSAR model calculations the substance has only a very low potential for bioaccumulation through aquatic exposure.

Considering this one can assume that the availability of Sumilzer GP in the sediment environment is generally low, which reduces the probability of chronic exposure of sediment organisms in general.

 

Aquatic ecotoxicity data

Short-term aquatic toxicity tests of the substance to fish, invertebrates, algae and microorganisms showed no adverse effects in the range of the water solubility. The obtained results indicate that Sumilizer GP is likely to show no toxicity to sediment organisms as well.

 

Conclusion

Due to its log Koc value of > 5, significant adsorption of this substance to activated sludge in conventional STPs will take place and only low concentrations are expected to be released (if at all) into the environment. Once present in the aquatic compartment, due to the high log Kow, low water solubility and high adsorption potential, Sumilizer GP will be bioavailable to sediment organisms mainly via feed and contact with suspended organic particles. However, based on the molecular weight, size and structure of the substance the uptake from medium into sediment organisms is considered to be low. This is supported by a bioaccumulation study using aquatic exposure, and the result of QSAR model calculations of the substance. Furthermore, aquatic toxicity data show that no effects occur up to the limit of water solubility. Therefore, Sumilizer GP is unlikely to pose a risk for sediment organisms in general and testing is thus omitted.