Iron ores, agglomerates

Toxicity to aquatic plants other than algae

Administrative data

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The structure of iron ore pellets consists essentially of iron oxide grains. The bonding of the grains occur by oxide bridging, recrystallisation of hematite and to a lesser extent by the formation of fused silicate phases. Since silicates are inert and no effect on the environment is expected, the endpoints in Chapters 5 and 6 are based on the effects of iron as a worst case in these substances. More information on the justification of read across can be found in the attached document in the endpoint summaries of section 5 and 6.

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Applicant's summary and conclusion

Conclusions:

Available data do suggest that iron salts are relatively non toxic and this was sufficient for the EU Classification and Labelling Committee to determine that there was no need for classification of iron salts. It was also concluded that iron massive and sparingly soluble forms of iron are highly insoluble and non-hazardous. Literary studies have extensively used test solutions with iron concentrations above that of its solubility limit. Due to physical effects of precipitated material some of these studies are meaningless for the investigation of intrinsic toxicity. Iron ions released to surface waters quickly form insoluble iron hydroxides in mixing zones. These positively charged iron (III) colloids will react with the negatively charge mucus that lines the fish gill. This accumulation of iron on the fish gill results in physical effects. Iron has complex redox chemistry. In very special conditions transient iron species can be formed that cause toxicity. These conditions however are not typical of most ambient conditions and are more representative of specific mixing zones. In ambient conditions, the dissolved natural background concentrations of iron, in most cases, are at equilibrium therefore an addition of iron would lead to the precipitation of iron compounds from solution and are therefore not intrinsically toxic. Therefore a PNEC is not required. More information can be found in the attached position paper and WCA report on the aqueous environmental chemistry of iron.