Iodine pentafluoride

Ecotoxicological Summary

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

General:

For iodine pentafluoride no aquatic toxicity studies with the substance itself are available or can be performed as in contact with water iodine pentafluoride reacts instantly and violently under formation of hydrogen fluoride and iodate. Hydrogen fluoride will further react to fluoride, iodate in water forms an equilibrium with iodide. Therefore available data from studies with fluoride, iodate and iodide are given as indication of the aquatic toxicity of iodine pentafluoride. Where no data on iodate and iodide is available, read across is made to the aquatic toxicity data of iodine. In that case, as the exact ratio of iodate and iodide in fresh and marine waters is not known (and variable depending on environmental parameters), one mole of iodine is considered to exist in water as either 2 moles of iodate or two moles of iodide. Both assumptions are considered to represent a realistic worst-case situation. For the different read across candidates, at least one short-term L(E)C50 value is available from each of three trophic levels (fish, aquatic invertebrates and algae) representing different taxonomic groups.

PNEC freshwater:

Iodate/iodide:

The critical effect value for freshwater species is a 72-h ErC50 of 0.13 mg iodine/L as observed in algae. Iodine is considered to exist in water only as iodide and iodate in equilibrium, formation of additional inorganic and organic iodine species from further reactions of iodate and iodide (or iodine itself) are not taken into account. When the effect value for iodine is recalculated based on molecular weights of iodate and iodide, this leads to effects values of 0.18 mg/L for iodate and 0.13 mg/L for iodide. Application of a default assessment factor of 1000, gives freshwater PNEC values for iodate and iodide of 0.18 µg/L and 0.13 µg/L, respectively. However, monitoring data show that EU background concentrations of iodide in European surface waters reach typical concentrations of about 0.1 -18 µg/L with a median value of 0.33 µg/L (US-DHHS, 2004; FOREGS database). As these values are higher than the PNEC derived from the available experimental data, the median background concentration is considered to be more relevant for PNEC determination. Based on the formation of equilibrium of iodide and iodate in aqueous environments, the reported median iodide concentration is considered to be equally protective for both iodide and iodate. Consequently, the PNEC freshwater is determined at 0.33 µg/L for both iodine species.

Fluoride:

For fluoride both short-term and long-term ecotoxicity data are available from the EU Risk Assessment Report (EU-RAR) on hydrogen fluoride. In this report all available ecotoxicity data from studies with sodium fluoride are evaluated and a PNEC for the freshwater compartment is determined on the basis of the calculated mean NOEC value of 8.9 mg fluoride/L from two 21-d studies with Daphna and a default assessment factor of 10. This gives a PNEC freshwater of 0.9 m/L. As iodine pentafluoride instantly hydrolyses to hydrogen fluoride and iodate, this PNEC is considered to be directly applicable for the assessment of fluoride from iodine pentafluoride. Thus, for fluoride the PNEC is determined at 0.9 mg/L.

PNEC saltwater:

Iodate/iodide:

For iodate, iodide and iodine no studies with marine species are available. In the marine environment iodate and iodide are also the predominant iodine species although ratios of the two may differ from those in freshwater. Background concentrations of iodine in seawater are reported to be 50 -60 µg/L (US-DHHS, 2004; FOREGS database) and thus significantly higher than those reported for freshwater. Although ratios of iodate and iodide in marine water may differ from those in freshwater, based on the above mentioned assumptions, the background levels of these iodine species are likely to be comparable to those reported for iodine. As in addition marine background concentrations for iodate and iodide would be considerably higher than the derived freshwater PNECs, derivation of a separate PNEC marine is considered to be unnecessary. Instead, the PNEC for freshwater is applied also in the assessment of the marine environment. Consequently, for marine water, the PNEC is determined at 0.33 µg/L for both iodate and iodide.

Fluoride:

In the EU-RAR for fluoride, short-term and long-term studies with saltwater species are either lacking or have limitations in design and or reporting. A PNEC for marine waters was not derived. As background concentrations of fluoride are 7-fold higher in seawater than in freshwater, and in addition marine background concentrations are higher than the PNEC aqua of 0.9 mg/L, derivation of a separate PNEC marine is considered to be unnecessary. Instead, the PNEC for freshwater is applied also in assessment of the marine environment. The PNEC marine is determined at 0.9 mg/L.

PNEC intermittent:

Iodine pentafluoride releases originate from continuous processes, not intermittent (i.e. less than once per month for no more than 24 hours). Therefore, a PNEC intermittent is not derived for the iodine species and fluoride.

PNEC STP:

Iodate/iodide:

The critical effect value for STP microorganisms is a 3-h NOEC of 110 mg iodine/L as observed in the respiration inhibition study with activated sludge. When the effect value for iodine is recalculated based on molecular weights of iodate and iodide, this leads to effects values of 152 mg/L for iodate and 110 mg/L for iodide. In accordance with REACH guidance R.10, a default assessment factor of 10 is to be applied based on the data availability. Consequently, for freshwater, the PNECs for iodate and iodide are 15.2 mg/L and 11.0 mg/L, respectively.

Fluoride:

In the EU-RAR for fluoride, both short-term and long-term studies with micro-organisms are available. After evaluation of all available data, the PNEC for microorganisms is in the EU-RAR determined based on a 3-h NOEC of 510 mg/L from an activated sludge test and application of a default assessment factor of 10 based on the data used. This gives a PNEC STP of 51 mg/L.

PNEC sediment (freshwater):

Iodate/iodide:

No sediment toxicity data are available for any of the iodine species and no environmental monitoring data were found. In accordance with column 2 of REACH annex IX, in the absence of toxicity data for sediment organisms, a PNEC for sediment may be calculated from the PNEC for freshwater using the Equilibrium Partitioning Method (EPM). For iodate and iodide this calculation was performed in EUSES (v2.1.1) using the PNEC of 0.33 µg/L and their respective geomean Koc values of 377 L/kg and 74 L/kg. For freshwater sediment, this would give PNECs for iodate and iodide of 0.0136 mg/kg d.w. and 0.00363 mg/kg d.w., respectively. However, compared to the reported background concentrations in soil (see below), and considering the available partitioning data for sediment and soil, these calculated PNECs are considered likely to be overly conservative. Therefore, it is considered more appropriate to estimate background concentrations in sediment based on the available soil background concentration and the ratio of Ksusp-water/RHOsusp (for sediment) versus Ksoil-water/RHOsoil (for soil) as used in the equilibrium partitioning method (see REACH guidance R.10 and R.16) and to use these estimated value as the PNECs for sediment. By doing so, sediment background concentrations for iodate and iodide are calculated to be 5.22 mg/kg dw and 6.22 mg/kg dw, respectively. From these values, the lower estimate is considered most appropriate for risk assessment of both iodine species. Consequently, the PNEC for sediment is determined at 5.22 mg/kg dw for both iodate and iodide.

Fluoride:

In the EU-RAR no quantitative risk assessment is carried out for the sediment department as there are no measured data for fluoride levels in sediment and no ecotoxicity data for the compartment. Therefore, a provisional PNEC sediment is calculated using the EPM on the basis of the PNEC freshwater of 0.9 mg/L and the sediment-water partitioning coefficient used in the assessment. For freshwater sediment, the PNEC is 3.52 mg/kg d.w..

PNEC sediment (marine water):

Iodate/iodide:

For the same reasons that for iodate and iodide no separate PNECs for marine water were derived, no separate PNECs for marine sediment are derived. The PNECs for freshwater sediment are applied in both the assessment of the freshwater and saltwater compartment. For marine sediment, the PNEC for iodate and iodide is determined at 5.22 mg/kg dw.

Fluoride:

For the same reasons that for fluoride no separate PNEC for marine water is derived, no separate PNEC for marine sediment is derived. The PNEC for freshwater sediment is applied in both the assessment of the freshwater and saltwater compartment. For marine sediment, the PNEC is 3.52 mg/kg d.w..  

PNEC soil:

Iodate/iodide:

No terrestrial toxicity data are available for any of the iodine species. In accordance with column 2 of REACH annex IX, in the absence of toxicity data for soil organisms, a PNEC soil may be calculated from the PNEC for freshwater using the Equilibrium Partitioning Method (EPM). For iodate and iodide this calculation was performed in EUSES (v2.1.1) using the PNEC of 0.33 µg/L and respective geomean Koc values of 377 L/kg and 74 L/kg. For the soil compartment, the PNECs for iodate and iodide are calculated to be 0.00253 mg/kg d.w.and 0.000532 mg/kg d.w., respectively. However, EU background concentrations of iodine in (top-) soil of up to 70.8 mg/kg are reported with a median value of 3.94 mg/kg (FOREGS database). Therefore, the monitored baseline level of iodine in European soils is considered more relevant for PNEC determination. Based on the formation of equilibrium of iodide and iodate in soil aqueous environments (e.g. groundwater), and the comparable partitioning coefficients (below one order of magnitude difference) the reported iodine concentration is considered to be applicable as PNEC value for both iodide and iodate. Consequently, the PNEC for soil is determined at 3.94 mg/kg d.w. for both iodine species (as a worst-case assumption, the reported value is considered to be based on a soil-dryweight basis).

Fluoride:

In the EU-RAR for fluoride, studies with several different terrestrial macro- and micro-organisms are available. After evaluation of all available data, the PNEC for the soil compartment is in the EU-RAR determined based on a 63-d nitrification study with a NOEC of 106 mg/kg d.w. and a default assessment factor of 10 based on the data used. This gives a PNEC soil of 11 mg/L. However, in the EU-RAR reference is made to several member state target values for total fluoride in different soils.

The mean fluoride concentration in mineral soil is 200 to 300 mg/kg; whereas that of organic soils is generally lower (97 mg/kg). In the Netherlands the fluoride concentrations in clay soils range from 80 to 700 mg/kg dw. In soils with higher pH values a higher amount of soluble F-complexes is found. Because the variation in background levels throughout Europe is substantial, the Dutch reference value is used. This gives a PNEC soil of 500 mg/kg d.w.

Conclusion on classification

As no aquatic toxicity studies with iodine pentafluoride are available or can be performed, classification criteria are compared with the data available on the different decomposition products fluoride, iodate and iodide. Data on iodine is considered when data on iodate and/or iodide is lacking. The concept of rapid degradability does not apply to inorganic substances. Therefore, the substance and its decomposition products are to be qualified as non-rapidly degradable. From all the available ecotoxicological endpoints, the 72 -h ErC50 value of 0.13 mg/L and NOEC of 0.025 mg/L for iodide, are critical for classification. Based on these data iodine pentafluoride is to be classified as aquatic acute category 1 (H400; very toxic to aquatic life) and as aquatic chronic category 1 (H410; very toxic to aquatic life with long lasting effects). To both classifications a M-factor of 1 is to be applied.