Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
0.383 mg/L
Assessment factor:
10
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
0.31 mg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.038 mg/L
Assessment factor:
100
Extrapolation method:
assessment factor

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
790 mg/L
Assessment factor:
10
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
1 088 mg/kg sediment dw
Assessment factor:
10
Extrapolation method:
equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
108.8 mg/kg sediment dw
Assessment factor:
10
Extrapolation method:
equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
2.33 mg/kg soil dw
Assessment factor:
10
Extrapolation method:
assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

All PNECs derived are in concentration tungsten ion, as toxicity is expected to occur from the metal ion.

Conclusion on classification

Aquatic toxicity classification of inorganic metals and metal compounds is conducted by comparing transformation/dissolution (T/D) data for the substance, generated using the standard protocol (UN GHS, Annex 10) [see Table 3 in Section 1.3 for results] with toxicity data for the most soluble metal substance as described in the CLP technical guidance (section IV. 5 Application of classification criteria to metals and metal compounds) (EU, 2008). The T/D data is ideally tested at the pH at which the highest dissolution is expected, within the range defined by the test protocol (pH 5.5-8.5). Since inorganic tungsten substances have been demonstrated to have a higher T/D rate at pH 8 than pH 6, the data used for aquatic toxicity classification of tungsten dioxide was derived at pH 8 (24-hour, 7-, and 28-day T/D testing) (CIMM, 2012). These T/D values were compared to the corresponding acute (31000 μg W/L, based on the ErC50) and chronic (3830 μg W/L, based on the ErC10) aquatic toxicity reference values derived from sodium tungstate testing of algae, as the most sensitive standard aquatic species for sodium tungstate. The results of this comparison demonstrate that tungsten dioxide does not classify for aquatic toxicity (see table below).

Classification of tungsten dioxide using T/D data comparison to toxicity data according to the CLP technical guidance (European Chemicals Bureau, 2009)

 

Test type/duration

T/D loading amount as WO2[mg/L]

T/D results [µg W/L]

pH 8

Toxicity reference value [µg/ W/L]

Comparison of T/D and toxicity values [µg/ W/L]

Aquatic Toxicity Classification Result

Screening test / 24-hour

100

72

Acute = 31000

72 < 31000

Refer to full T/D test for classification

Acute full test / 7-days

1

33

Acute = 31000

33 < 31000

No classification for acute hazards

Acute full test / 7-days

10

239

Acute = 31000

239 < 31000

No Chronic 2 classification

Acute full test / 7-days

100

4225

Acute = 31000

4225 < 31000

No Chronic 3 classification

Chronic full test / 28-days

1

106

Chronic = 3830

106 < 3830

No Chronic 2 classification

 

The CLP classification scheme for evaluating aquatic toxicity of metals and metal compounds is the same as that used to classify metals and metal compounds under the Dangerous Substances Directive, with the exception of the name of the classifications (e.g. DSD cites R phrases, CLP uses acute and chronic categories). Although the DSD does not specifically cite the classification scheme for metals and metal compounds, the scheme was outlined in the ECB documents used in the classification of nickel metal (massive and powder). In addition, this classification scheme was used to evaluate aquatic toxicity of nickel metal and some copper compounds (ECB, 2001; ECB, 2005).