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Ecotoxicological information

Ecotoxicological Summary

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Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
7.1 µg/L
Assessment factor:
1
Extrapolation method:
sensitivity distribution
PNEC freshwater (intermittent releases):
0 µg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
8.6 µg/L
Assessment factor:
2
Extrapolation method:
sensitivity distribution
PNEC marine water (intermittent releases):
0 µg/L

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
0.33 mg/L
Assessment factor:
100
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
109 mg/kg sediment dw
Assessment factor:
1
Extrapolation method:
sensitivity distribution

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
109 mg/kg sediment dw
Assessment factor:
1
Extrapolation method:
sensitivity distribution

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
29.9 mg/kg soil dw
Assessment factor:
2
Extrapolation method:
sensitivity distribution

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
PNEC oral
PNEC value:
0.12 mg/kg food
Assessment factor:
10

Additional information

The approach for deriving PNEC values was used in the 2008/2009 European Union Existing Substances Risk Assessment of Nickel (EU RAR) (EEC 793/93). The EU RAR was jointly prepared by the Danish Environmental Protection Agency (DEPA), which served as the Rapporteur of the Existing Substances Risk Assessment of Nickel, and the Nickel Producers Environmental Research Association (NiPERA), which represented the Nickel Industry in this process. The complete Environment section of the EU RAR can be found in the pdf linked to the following URL:

 http://ecb.jrc.ec.europa.eu/DOCUMENTS/Existing-Chemicals/RISK_ASSESSMENT/REPORT/nickelreport311.pdf

 

All of the approaches described were discussed by the Technical Committee for New and Existing Substances (TC NES), and received final approval at the TC NES I meeting in April, 2008.

 

Common effects assessment basis:

 

The ecotoxicity databases on the effects of soluble nickel compounds to aquatic, soil- and sediment-dwelling organisms are extensive. It should be noted that the effects assessments of Nickel oxide is based on the assumption that adverse effects to aquatic, soil- and sediment-dwelling organisms are a consequence of exposure to the bioavailable Ni-ion, as opposed to the parent substances. The result of this assumption is that the ecotoxicology will be similar for all soluble Ni substances used in the ecotoxicity experiments. Therefore, data from soluble nickel substances are used in the derivation of chronic ecotoxicological NOEC and L(E)C10 values. If both NOEC and L(E)C10 data are available for a given species, the L(E)C10 value was used in the effects assessment.

Conclusion on classification

Ni oxide is currently classified as Aquatic Chronic 4 (H413: May cause long lasting harmful effects to aquatic life) according to the 1st ATP to the CLP Regulation. However, a recent study evaluating the transformation and dissolution of green Ni oxide using the T/D Protocol (OECD, 2001) found it to be essentially unreactive. The results of the study indicate that the net concentration change in total dissolved Ni for the seven- and 28 day test at 1 mg/L loading at pH 6 and at pH 8 was less than the pH 6 acute, pH 8 acute, and chronic Ecotoxicity Reference Values (ERVs) for Ni (120 µg Ni/L at pH 6, 68 µg Ni/L at pH 8, and 2.4 µg Ni/L, respectively). Specifically, dissolved Ni concentrations were 0.23 µg Ni/L and <0.1 µg Ni/L at pH 6 and pH 8, respectively. The 10 and 100 mg/L loadings for the seven-day tests at pH 6 and 8 exhibited similar sub µg/L values of total dissolved Ni, which were all below the respective ERVs. Since the total dissolved Ni concentrations for the 7-day acute tests for all loadings and the 28-day chronic test were all significantly less than the respective Ni ERVs, the green Ni oxide would not classify under the GHS. While no change to the existing classification is proposed within this registration file, the results of the T/D P testing on green NiO can be found in Section 5.6 of IUCLID.

Ni oxide is currently classified as Aquatic Chronic 4 (H413: May cause long lasting harmful effects to aquatic life) according to the 1st ATP to the CLP Regulation. However, a recent study evaluating the transformation and dissolution of black Ni oxide using the T/D Protocol (OECD, 2001) suggests that a more stringent classification would be appropriate. The results of the study indicate that the net concentration changes in total dissolved Ni for the seven day test at the 1 mg/L loading at pH 6 was 82.8 µg Ni/L and 11.7 µg Ni/L at pH 8. These dissolved Ni concentrations were less than the pH 6 acute and pH 8 acute Ecotoxicity Reference Values (ERVs) for Ni (120 µg Ni/L at pH 6, and 68 µg Ni/L at pH 8, respectively). Based on these results, the black Ni oxide would not classify as Aquatic Chronic 1 (H410: Very toxic to aquatic life with long lasting effects). The 10 mg/L loading was not tested at either pH 6 or 8, but extrapolation of the 1 mg/L loading rate results to a loading rate of 10 mg/L suggests that dissolution at 10 mg/L would exceed the acute ERVs (i.e., assuming that a 10-fold difference in dissolved Ni would accompany the difference in loading rate from 1 to 10 mg/L, dissolved Ni concentrations of approximately 830 µg Ni/L at pH 6 and 120 µg Ni/L at pH 8 would be expected). Exceedance of ERVs at the 10 mg/L loading rate would result in an appropriate classification for black Ni oxide as Aquatic Chronic 2 (H411: Toxic to aquatic life with long lasting effects). While no change to the existing classification is proposed within this registration file, the results of the T/D P testing on black NiO can be found in Section 5.6 of IUCLID.

The 2ndATP to the CLP introduced the chronic (long-term) environmental toxicity endpoint as defined by the 3rdversion of the UN-GHS into the EU hazard classification and labeling scheme. The GHS and EU scheme include the concept of degradation whereby rapid degradation from the water column (greater than 70 % removal in 28 days) results in different classification cut-off values and categories.  For metals and inorganic metal compounds, the rapid and irreversible removal from the water column is equated to the rapid degradation concept for organics.  The current draft guidance on metals includes  a proposal to apply the “rapid degradation principle for organics” measured as a 70 % removal rate in 28 days in a comparable way for metals from laboratory and field experiments or by using a recently developed model.  A Unit World Model (UWM) has recently been developed specifically for metals, building on previous screening-level calculations that have been developed for organic contaminants, and is capable of assessing the fate and effects of chemicals by the simultaneous consideration of chemical partitioning, transport, reactivity, and bioavailability.  With regard to hazard assessment, the UWM is capable of assessing the removal of soluble metals from the water column resulting from sorption to particulate material, settling to the sediment compartment, and subsequent changes in speciation via precipitation by sulfides naturally present in the sediment compartment. 

 

The UWM was used to assess the rapid removal of a group metals (e.g., Ni, Cu, Pb, Zn, As, Al, Co) in a generalized lake environment resulting from metal removal from the water column and sequestration in sediment.  To estimate sorption by particulate matter in the water column, the UWM can use empirical, measured distribution coefficients (Kd), or the speciation module within the UWM (the Windermere Humic Aqueous Model, or WHAM) can calculate Kds. When an empirical Kd of log 4.42 was used, greater than 70% nickel removal was achieved in every loading and pH scenario. WHAM-based Kds tended to be substantially lower than empirical Kds, indicating that refinement of the WHAM approach was needed. To this end, the UWM was refined to accommodate an updated version of WHAM (WHAM 7). Additionally, the inorganic thermodynamic database used by WHAM to perform speciation calculations was updated because the previous version was found to be out of date and inaccurate. Analyses using WHAM7 and the revised inorganic thermodynamic database showed that greater than 70% nickel removal was achieved under the three pH scenarios with metal loadings at the acute and chronic ERVs at 28 days.  At the upper chronic cutoff value of 1 mg/L, rapid removal was achieved for pH 6 and 8 without oxide binding and for all three pH values with oxide binding.  Rapid removal was demonstrated at all pH values when loading was based on acute Ecotoxicity Reference Values (120 µg Ni/L at pH 6 and 68 µg Ni/L at pH 8) and chronic Ecotoxicity Reference Values (2.4 µg Ni/L) using calculated Kd values. Based on these results, nickel oxide fulfills the criteria for rapid degradation for the environmental classification scheme in the 2ndATP to the CLP.