Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Additional information

COPPER IODIDE

The environmental hazard associated with copper iodide is assessed in terms of the toxicity of copper and iodide ions released during dissociation of the compound in the aqueous phase.

 

Summary information on the toxicity of copper and iodide ions to algae and cyanobacteria is presented below.

COPPER:

Short description of key information:

High quality single-species EC50 values and NOEC/(L(E) C10 values are available for 3 freshwater algae species. A chronic Biotic Ligand Model was developed for S. Subcapitata and validated for 3 additional speicies. The NOECs and the chronic algae Biotic ligand models (BLM) are carried forward to the risk characterisation. High quality chronic single-species NOEC/(L(E) C10 values are available for 4marine algae species. The observed effects are related to the organic carbon content of the test waters. The NOECS and organic carbon relationships are carried forward to the risk characterisation.

Discussion:

Freshwater algae NOECS

High quality chronic NOEC/(L(E) C10 values are available for 3 species:Chlamydomonas reinhardti, Chlorella vulgaris and Pseudokirchernella subcapitata.

The NOECs were used to calculate high quality “species geometric mean” NOEC values for each endpoint and the most sensitive endpoint for each of the algae species was retained as "species-mean" NOEC. The "species mean" NOEC value range from 43 µg/l Cu forPseudokirchernella subcapitata(endpoint growth; n=4) to 138 µg/l Cu forChlorella vulgaris(endpoint growth; n=17). These values are used for the PNEC derivation.

 Large intra-species variability are observed. The effects data-set fromPseudokirchernella subcapitatawas used for the development of an algae BLM (De Schamphelaere et al, 2003) The capacity of the BLM for predicting copper toxicity to other algae species was demonstrated from copper toxicity studies withChlamydomonas reinhardtiandChlorella vulgaris(De schamplelaere and Janssen, 2006).

Research related to copper acclimation and deficiency (Bossuyt et al, 2004) demonstrated that, based on the algal biomass, the growth rate, the pigment diversity and the autotrophic index, an optimal concentration range was observed between 1 and 35µg Cu/L. Deficiency was observed at lower levels, toxicity was observed at higher levels.

Marine algae NOECS

High quality chronic NOEC values are available for 4 species: 2 diatoms (Phaeodactylum tricornutumandSkeletonema costatum) and 2 macroalgae (Macrocystis pyriferaandFucus vesiculosis). Individual NOEC values range between 2.9 µg Cu/L (Phaeodactylum tricornutum, growth) to 50 µg Cu/L(MacrocystisPyrifera, germination).

High quality “species mean” NOEC values are derived for the most sensitive endpoint for each of the 4 species of marine algae. The"species mean" NOEC value range from 2.9 µg/l Cu for thePhaeodactylum tricornutumto 11 µg/l forFucus vesiculosis. Large intra-species variability are observed due differences inDOC. A relation between the observed NOEC and organic carbon content was established forFucus vesuculosis.

IODINE:

Short description of key information:

Toxicity to aquatic algae: EC50 (72 hours): 0.13 mg/l; NOEC (72 hours): 0.025 mg/l

Key value for chemical safety assessment:

EC/LC50 for freshwater algae: 0.13 mg/L

EC10/LC10 or NOEC for freshwater algae: 0.025 mg/L

Discussion:

The reviewed 72 hour study investigated the aquatic toxicity of iodine to algae (Desmodesmus subspicatus). As this study was conducted to OECD Guideline 201: Alga, Growth Inhibition Test, this is considered to meet the Klimisch reliability criteria of 1 - reliable without restriction. The results were based on the 0-Hour measured test concentrations only as the highest test concentration saw a decline to 76% of the 0-Hour measured test concentration. Given that this was the highest test concentration employed which was far in excess of the EC50 values it was considered appropriate to calculate the results based on the 0-Hour measured test concentrations only. Based on the calculations, the 72 hour EC50 for growth rate was 0.13 mg/L and the NOEC for growth rate was 0.025 mg/L.