Iron dichloride

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

no hazard identified

Marine water

Hazard assessment conclusion:

no hazard identified

STP

Hazard assessment conclusion:

no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:

no hazard identified

Sediment (marine water)

Hazard assessment conclusion:

no hazard identified

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

If the submission item category member soluble iron salts will -following the supported uses- arrive in environmental waters, they will after transformation steps be present as an equilibrated mixture of chemical species, which depend on the geochemical conditions in the waters, sediments and soils, while the original oxidation state and the counteranions are irrelevant. Therefore the submission category is well justified as demonstrated in the section on physical and chemical properties, where the data are presented in the Reporting Format for the Chemical Category according to ECHA Guidance on QSARs and grouping of chemicals (2008, R.6.2.6.2).

• ECHA European Chemicals Agency (2008). Guidance on information requirements and chemical safety assessment Chapter R.6: QSARs and grouping of chemicals. Self-published, Helsinki, Finland, in May. 134 p.

Effect data

For the purpose of the EURAS critical review a significant literature screening was conducted (Vangheluwe & Versonnen 2004). Another literature review and evaluation was performed by the U.K. environmental agency (Johnson 2007).

The effects in short-term tests are observed at nominal exposure concentrations in the range 10 – 1000 mg/L salt with the majority being in the range 10 – 100 mg/L. Effects arising from long-term exposures are observed at nominal concentrations in the order of 1 - 10 mg/L. At all of these concentrations it can be expected that, under the test conditions, most of the iron will be present as undissolved and precipitated ferric hydroxide. It is therefore highly likely that observed effects on fish and invertebrates will be due to smothering or clogging of the gills or respiratory membranes. Filtrating organisms like daphnids would ingest precipitating particles and therefore by unable to feed normally. Effects on aquatic plants and algae will be due to impairment of photosynthesis by light interception. Growth of aquatic plants and algae can also be inhibited as a consequence of nutrient (phosphate) chelation.

As discussed in the section on Sediment and Soil Toxicity, the submission category belongs to the lowest “soil hazard category 1” and thus the straightforward application of the EPM for derivation of PNECs for sediments and soils is enabled, but as no aquatic PNECs were derived this is obsolete and no PNECs for sediments or soils are required.

The effects of iron salts to the aquatic life have been assessed earlier by Johnson et al (2007) with the result that no meaningful threshold level can be derived. On the basis of these data and the ones in the review of Vangheluwe & Versonnen (2004) the lack of intrinsic toxicity to aquatic, sediment and terrestrial organisms is considered. Accordingly absence of relevant effects to sediment and terrestrial organisms (U.S. EPA OSWER 2003) can be concluded. However a large number of publications report effects, none of the experimental approaches fulfils the Hill (1965) criteria for causation of intrinsic toxicity.

• Hill AB (1965). The environment and disease: association or causation? Proceedings of the Royal Society of Medicine 58:295-300.
• Johnson I, Sorokin N, Atkinson C, Rule K, Hope S-J (2007). Proposed EQS for Water Framework Directive Annex VIII substances: iron (total dissolved). ISBN: 978-1-84432-660-0. Science Report: SC040038/SR9. SNIFFER Report: WFD52(ix). Product Code SCHO0407BLWB-E-E. Self-published by Environment Agency, Almondsbury, Bristol BS32 4UD, U.K. 65 p.
• Vangheluwe M, Versonnen B (2004). Critical review on acute and chronic aquatic ecotoxicity data to be used for classification purposes of iron sulfate. Commissioned by ARCELOR SA, CEFIC, EUROFER, RIO TINTO plc. Final report - 25 August 2004. Prepared by EURAS, Rijvisschestraat 118, box 3. B-9052 Gent, Belgium. 76 p.
• U.S. EPA OSWER United States Environmental Protection Agency Office of Solid Waste and Emergency Response (2003). Ecological Soil Screening Level for Iron. Interim Final. Self-published, Washington, DC, U.S.A. in November 2003 as Directive 9285.7-69. 44 p.

Adequacy and relevance of existing data and possible guideline studies according to Hill criteria

These criteria were first published by Austin Bradford Hill (1965) establishing cause and effect in medical diagnosis and are generally accepted for reasoning and assessing causation. Nine factors are to consider “before we cry causation” (Hill 1965, p 299):

Table: Overview on the Hill criteria of causation (Hill 1965)

Number	Subject	Comment
1	Strength (statistical significance)	A correlation coefficient of 1 indicates maximum strength of the association between the supposed cause and effect and the closer the actual value the more causation is supported.
2	Consistency (between observations in nature and experiment)	The agreement of different observations in nature and experimental settings covering a wide range of circumstances is desirable and supports causation.
3	Specificity (monocausation of effects)	The assumption of causation is supported if the relationship is specific, i.e. if there is no other plausible explanation of the observable effects.
4	Temporality (time relationship between treatment and effect)	A close time relationship between the supposed cause and the observed effects are postulated unless the mode of action explains different circumstances.
5	Biological gradient (clear dose response relation)	The dose-response relationship should show a clear dose dependency of the observed effects. Nonetheless this does not need to be a simple linear relationship and may have minimum and maximum thresholds, excursive characteristics in the mid-range argue against monocausation.
6	Plausibility (mode of action model desirable)	This is a feature that cannot be demanded however it supports causation to have an idea of the relevant mode of action.
7	Coherence (with empiricism)	Laboratory experiments and external everyday evidence should be in alignment.
8	Experiment (to confirm epidemiologic correlations)	Evidence from experiments should be used to confirm epidemiologically based assumptions whenever possible.
9	Analogy (analogue causation must be excluded)	When something is suspected of causing an effect, then other factors similar or analogous to the supposed cause should also be considered and identified as a possible cause or otherwise eliminated from the investigation.

Checking the criteria 2 and 3 in the studies for aquatic ecotoxicology revealed relevant inevitable weaknesses of the available laboratory tests (Johnson et al 2007, Vangheluwe & Versonnen 2004) and possible future experiments for ecotoxicological endpoints with soluble iron salts. Considering the unavoidableness of these problems standard testing is not insightful for assessing the aquatic environmental hazards and an adequate amendment of the protocol seems technically not feasible.

Consistency

Regarding the Consistency (criterion 2) the appropriate choice of the test organisms should be regarded. Generally standardized laboratory organisms were used in such studies. These clones were bred over generations in media composed on the basis of their needs rather than natural background concentrations of metal species, which were actively incorporated and specific bio-regulation applies. Thus the normal acclimation and adaptation gets lost. This constitutes an artificial situation as metals are naturally occurring in significant levels. It is in consequence questionable if laboratory animals are the relevant representative organisms of the three main trophic levels of the aquatic environment (micro-organisms are assumed to be less concerned) under these circumstances. The lack of consistency between non-anthropogenic natural background concentrations and aquatic effect or threshold levels of toxicity in tests is critical. An environmental threat may be not caused by these levels as contingent effects base on an artefact produced by sudden exposure of inadequate test organisms, which may have acclimated and adapted with time. These concerns are of general nature and relevant for all naturally occurring materials.

Specificity (monocausation)

No Specificity (criterion 3) of the observed effects (mono-causation) is assured. Molecular modes of action are not the only ones in case flocculation, coagulation, sorption and fouling of the test item can hamper mechanically vital functions of the test organisms. In semi-static or flow-through designs these processes start daily anew or go on permanently.

Sorption to surfaces of organisms or ingestion by filtrating organisms may constitute unrealistic exposure. Increased acidity, resulting from binding of hydroxyl ions (OH-) obtained from the ligand water molecules (to form iron hydroxyl complexes) with the release of hydrogen ions, may be detrimental to the test organisms, but is in the standard guideline tests excluded by buffering and pH control. Nutrient chelation, i.e. in particular the complexation and effective removal of dissolved phosphate plant nutrients may hamper the growth of plants and algae. In test employing photosynthetically active organisms, the reduction of availability of light through interception by precipitated or colloidal hydroxides may be another cause for reduced growth. In addition to that, fouling may encrust sensitive organs e.g. the filtration apparatus in cladocerans or the gills in fish, and hamper their efficiency up to dysfunction. The kinetics of the transformation processes of soluble iron salts are quick enough to affect the tests and may thus cause the recorded effects. No visual microscopic inspection was performed to give evidence for such mechanisms or their absence in the reliable literature studies available (Johnson et al 2007, Vangheluwe & Versonnen 2004).

The use of soluble iron salts in nominal concentrations above the final water solubility in equilibrium leads to exposure of the test organisms to in situ hydrolysing, polymerising and flocculating, precipitating or adhering iron species. This results in a generally unclear exposure to a number of chemical species, whose composition changes probably with the time. The iron species causative for the effects keep thus unclear.

Incorporation of else solute toxicants bound in the in larger particles resulting from flocculation cannot be excluded. This is even more relevant as the flocculation behaviour can result in oral exposure due to ingestion of iron complex clusters.

In result mixed effects of media exposure to unknown and variable dissolved materials and/or sorption and encrustation effecting mechanical blockage and/or ingestion and thus oral exposure and/or adhesion and thus enhanced bioavailability of unknown and variable undissolved materials may have caused the observed effects. Neither the substances (iron species) bioavailable to the test animals can be named nor whether the effects were caused by ingestion, media contact, surface sorption or mechanical blockage. Thus this Specificity criterion is clearly violated as several basic mechanisms could be involved in the causation.

In conclusion true, intrinsic toxicity of iron kation in aerobic aquatic test organisms cannot be determined in studies when the solubility of the dissolved ferric kation (as the ferrous form will readily be oxidized to ferric species) is exceeded.

• Hill AB (1965). The environment and disease: association or causation? Proceedings of the Royal Society of Medicine 58:295-300.
• Johnson I, Sorokin N, Atkinson C, Rule K, Hope S-J (2007). Proposed EQS for Water Framework Directive Annex VIII substances: iron (total dissolved). ISBN: 978-1-84432-660-0. Science Report: SC040038/SR9. SNIFFER Report: WFD52(ix). Product Code SCHO0407BLWB-E-E. Self-published by Environment Agency, Almondsbury, Bristol BS32 4UD, U.K. 65 p.
• Vangheluwe M, Versonnen B (2004). Critical review on acute and chronic aquatic ecotoxicity data to be used for classification purposes of iron sulfate. Commissioned by ARCELOR SA, CEFIC, EUROFER, RIO TINTO plc. Final report - 25 August 2004. Prepared by EURAS, Rijvisschestraat 118, box 3. B-9052 Gent, Belgium. 76 p.

Risk Characterization Approach

As discussed in the section on Environmental fate and pathways the environmental assessment of the submission item must be based on the metal kations considering their speciation, while the anions can be considered nontoxic and ubiquitary present in the environment in important amounts.

The levels considered as background concentrations in the present assessment are given in the section on Environmental fate and pathways. These background concentrations can be used in the environmental risk assessment and be compared with the respective PNEC according to ECHA (2008, R.7.13-2): In case the background is found significant compared to the PNEC, the Added Risk Approach will be to be applied, while in case PNECs are in the order of the background the Total Risk Approach will be used. Whenever no PNEC can be derived the background levels will be compared with PECadd (increase of the total concentration caused by the uses of the submission item). Insignificant PECadd compared to the background concentrations, will be evaluated as not hazardous to the environment. This can be assumed in the present cases of the submission item, particularly considering the fact that the bioavailable iron fraction results from geochemical conditions rather than release. Due to the rapid equilibration the released fraction contributes to immobilized soil and sediment species and will be buried in the important environmental sinks in sediments, suspended matter and soils evidenced by the significant natural background concentrations (section on Environmental fate and pathways). In consequence the PECadd will always be insignificant where dissolved ferric and ferrous irons are present at their level of solubility in environmental waters. This is generally the case with the sole exception of iron deficient biotopes.

However establishing formally PNECs, which is omitted here as the PNEC cannot be established on the basis of intrinsic toxicity (this restriction does not apply to the EQSs according to the WFD, Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000), the evaluation of aquatic iron effects performed by the U.K. authorities (Johnson et al 2007) negates their usability: “The ‘added risk’ approach could be appropriate when setting EQSs for iron. This is because iron is a naturally occurring substance that organisms will have been exposed to over an evolutionary timescale. In this case, the PNEC applies only to the ‘added’ contribution over and above the background level. A practical consequence of this is that compliance assessment would need to consider background levels of iron, at least at a regional scale, if not a local scale. However, natural background concentrations for iron are expected to be very high in comparison to anthropogenic inputs. In this case, a realistic option for implementation would be to set EQSs at background levels rather than on the basis of the PNECs proposed here.”

Iron is an essential trace element for fish, aquatic invertebrates, plants and algae its absence is detrimental for the environmental life and as iron plays an important role in biological processes its homeostasis in organisms is under strict control

Thus it is concluded that the derivation of a meaningful PNEC (a PNEC which can be compared with measured concentrations to indicate a risk to the environmental life) is not adequate and not required.

• ECHA European Chemicals Agency (2008). Guidance on information requirements and chemical safety assessment Appendix R.7.13-2: Environmental risk assessment for metals and metal compounds. 74 p.
• Johnson I, Sorokin N, Atkinson C, Rule K, Hope S-J (2007). Proposed EQS for Water Framework Directive Annex VIII substances: iron (total dissolved). ISBN: 978-1-84432-660-0. Science Report: SC040038/SR9. SNIFFER Report: WFD52(ix). Product Code SCHO0407BLWB-E-E. Self-published by Environment Agency, Almondsbury, Bristol BS32 4UD, U.K. 65 p.

Secondary poisoning

Johnson et al (2007) summarized “Iron is an essential element that has been shown not to bioaccumulate in higher organisms. This is because absorption of iron depends on an organism’s requirements for iron and this is regulated so that excessive amounts of iron are not stored in the body. It is, therefore, considered unnecessary to derive a PNEC addressing secondary poisoning of predators.”

Iron is an essential micronutrient and present in all organisms in considerable amounts. IOM (2001) evaluated the total iron intake as follows (values refer to elemental iron assuming a body weight of 60 kg): “The Recommended Dietary Allowance (RDA) for all age groups of men and postmenopausal women is 8 mg/day; the RDA for premenopausal women is 18 mg/day. The median dietary intake of iron is approximately 16 to 18 mg/day for men and 12 mg/day for women. The Tolerable Upper Intake Level (UL) for adults is 45 mg/day of iron, a level based on gastrointestinal distress as an adverse effect.”

• Johnson I, Sorokin N, Atkinson C, Rule K, Hope S-J (2007). Proposed EQS for Water Framework Directive Annex VIII substances: iron (total dissolved). ISBN: 978-1-84432-660-0. Science Report: SC040038/SR9. SNIFFER Report: WFD52(ix). Product Code SCHO0407BLWB-E-E. Self-published by Environment Agency, Almondsbury, Bristol BS32 4UD, U.K. 65 p.
• IOM Institute of Medicine (2001). Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. A Report of the Panel on Micronutrients, Subcommittees on Upper Reference Levels of Nutrients and of Interpretation and Uses of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. ISBN 0-309-07279-4 (PBK) ISBN 0-309-07290-5 (HC) National Academy Press, Food and Nutrition Board, IOM, National Academy of Sciences in April, Washington, DC, U.S.A. 800 p.

Conclusion on classification

The following statements base on DSD, the Commission Directive 2001/59/EC (28th ATP of Council Directive 67/548/EEC), and CLP (5th ATP of Regulation (EC) No 1272/2008 of the European Parliament and of the Council) as implementation of UN-GHS in the EU.

Harmonized Classification

Iron (II) chloride and the soluble iron (III) salts are not legally (harmonized) classified in accordance with DSD and GHS/CLP regulations, while iron (II) sulphate in its anhydrous (index number 026-003-00-7) and heptahydrate (index number 026-003-01-4) forms is listed in Tables 3.1 and 3.2, but not considered toxic to the aquatic environment.

Environmental hazards

The Rapid biodegradability condition applies

As discussed in the section on biodegradation in water: screening tests iron can be treated like rapidly biodegradable substances with regard to classification.

Absence of relevant, intrinsic toxicity

As discussed in the section on aquatic toxicity the submission item category member soluble iron salts are considered not toxic to the aquatic life.

As demonstrated by in ECHA guidance on CLP (2012, Table IV.7.1, p 553, Example D), the EURAS Critical review on acute and chronic aquatic ecotoxicity data (Vangheluwe & Versonnen 2004) can be employed for classification purposes of iron salts and to select the relevant studies for these endpoints, however the Klimisch rating of them may be revisited as precipitation of insolute test items may have caused test artefacts. In any case, i.e. even if using these data, no necessity for environmental is to be concluded.

In conclusion no classification for environmental hazard is required.

Table: Labelling elements based on the classification

Element	Code
GHS Pictogram	none
Signal Word	none
Hazard Statement	none
Precautionary statement(s)	none

• ECHA European Chemicals Agency (2012b). Guidance on the Application of the CLP Criteria. Version 3.0, November 2012. Self-published, Helsinki, Finland. Reference: ECHA-12-G-14-EN, Date: 11/2012. 573 p
• Vangheluwe M, Versonnen B (2004). Critical review on acute and chronic aquatic ecotoxicity data to be used for classification purposes of iron sulfate. Commissioned by ARCELOR SA, CEFIC, EUROFER, RIO TINTO plc. Final report - 25 August 2004. Prepared by EURAS, Rijvisschestraat 118, box 3. B-9052 Gent, Belgium. 76 p

Hazards to the ozone layer

A substance shall be classified as hazardous to the ozone layer (Category 1) if the available evidence concerning its properties and its predicted or observed environmental fate and behaviour indicate that it may present a danger to the structure and/or the functioning of the stratospheric ozone layer.

Volatilisation can generally be ignored for metals, except for several organometallic compounds, which are neither present in the submission item nor formed in the environment. Entering the atmosphere from water is irrelevant for the submission item due to the ionic nature of the constituents and no relevant release to the atmosphere is expected. Iron as contained in the submission item may exist in air as suspended particulate matter originating from industrial emissions or erosion of soils. Most of the metal species present in the atmosphere will be bound to aerosols, i.e. the aerosol-bound fraction is almost one. Metal containing particles are assumed to be mainly removed from the atmosphere by gravitational settling, with large particles tending to fall out faster than small particles. The half-life of airborne particles is assumed to be in the order of days. Some removal by washout mechanisms such as rain may also occur, although it is of minor significance in comparison to dry deposition. Indirect photolysis by hydroxyl radicals and direct phototransformation in the air are considered irrelevant, while speciation in airborne droplets may occur and include (photo)oxidation and hydrolysis.

In conclusion there is no indication that the soluble iron salt category could present a danger to the ozone layer as it is unlikely that it reaches the stratosphere. Thus no classification is required.