Trisodium, bis [2-((E)-(4-hydroxy-2-oxido-3-((E)-(5-sulfonatonaphthalen-1-yl)diazenyl)phenyl)diazenyl)benzoate] chromate(3-)

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.2 mg/L

Assessment factor:

50

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.26 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.02 mg/L

Assessment factor:

500

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

0.32 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.78 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.08 mg/kg sediment dw

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:

0.1 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

A long-term study to aquatic invertebrate and a toxicity study to algae are available, for which the following results were obtained: NOEC (Daphnia magna, 21 days) = 10.0 mg/l and NOEC (Scenedesmus subspicatus, 96 and 72 h)= 20 mg/l. Therefore, the most sensitive aquatic organism is considered to be Daphnia magna and for this reason the concentration of 10 mg/l [NOEC (Daphnia magna, 21 days)] is used for the PNEC calculation. Due to the nature of the substance, Daphnia can be considered as more representative organism than algae for the assessment of the aquatic toxicity potential.

Short-term results from three trophic levels are available. Short-term toxicity studies are available to fish (two studies) and aquatic invertebrate for which the following results ere obtained:LC50 (Oncorhynchus mykiss, 96 h) = 509,1  mg/l, LC50 (Oncorhynchus mykiss, 96 h) > 100 mg/l and EC50 (Daphnia magna, 48h) = 26 mg/l. For algae, an EbC50 (Scenedesmus subspicatus, 96 h) = 24.2 mg/L is determined, while the ErC50 is calculated to be between 20 and 80 mg/l (ca. 5 % growth inhibition at 20 mg/l and ca. 70 % growth inhibition at 80 mg/l). Due to the nature of the substance, Daphnia can be considered as more representative organism than algae for the assessment of the aquatic toxicity potential. Therefore, the EC50 (Daphnia magna, 48h) = 26 mg/l is considered for the PNEC intermittent release.

Assessment factors of 50 and 500 were used for fresh water and marine water, respectively.

The derivation of PNECwater, intermittent was done by applying an assessment factor of 100.

The value of PNECstp was derived using 32 mg/l derived from a toxicity study to microorganisms where the EC50 > 32 mg/l was observed.

Due to the lack of ecotoxicological data, PNECsediment for fresh water and marine water were calculated using equilibrium partitioning method. This method uses PNECwater for aquatic organisms and suspended matter/water partition coefficients as inputs. Bulk density of wet suspended matter is 1150 kg/m³. Note that this approach is used only as a rough screening since it may result in both an overestimation or underestimation of toxicity. The suspended matter-water partition coefficient was computed and resulted as 0.979 m³/m³. A correction factor of 4.6 from wet weight to dry weigth was applied to obtain the final PNECsediment.

The amount of test substance in the air compartment was expected to be very low, since the substance is a solid with a negligible vapour pressure. Therefore, no hazard was identified.

The calculation of PNECsoil was done using the equilibrium partitioning method, based on the assumption that soil toxicity, expressed in terms of freely-dissolved substance concentration in the pore water, is the same as aquatic toxicity. The pore water concentration is correlated with the bioavailable fraction. Note that this approach was originally developed for sediments but it may be applied to soil. In the calculation of PNECsoil, PNECwaterfor aquatic organisms and soil-water partition coefficient were used as inputs. Bulk density of wet soil is 1700 kg/m3. Soil-water partition coefficient was computed and resulted as 0.739 m³/m³. A correction factor of 1.13 from wet weight to dry weight was applied to obtain the final PNECsoil.

Secondary poisoning concerns toxic effects in the higher members of the food chain which results from ingestion of organisms from lower trophic levels that contain accumulated substances. It is relevant for highly lipophilic organic chemicals, with a log Pow above the cutoff value of 4 reported in the CLP Regulation (EC 1272/2008). Due to the absence of potential for bioaccumulation indicated by a log Pow of -2.33, test substance was considered as not hazardous with respect to secondary poisoning.

Conclusion on classification

According to the CLP Regulation (EC) no. 1272/2008, Part 4: Environmental Hazards, substances can be classified for aquatic environment hazard when the following criteria are met:

(a) Short-term (acute) aquatic hazard

Category Acute 1: 96 h LC₅₀(fish) and/or 48 h EC₅₀(crustacea) and/or 72 or 96 h E_rC₅₀(algae or other aquatic plants) ≤ 1 mg/l.

(b) Long-term (chronic) aquatic hazard

(i) Non-rapidly degradable substances (Note 3) for which there are adequate chronic toxicity data available

Category Chronic 1: Chronic NOEC or ECx (for fish)≤0,1 mg/l and/or Chronic NOEC or ECx (for crustacea)≤0,1 mg/l and/or Chronic NOEC or ECx (for algae or other aquatic plants)≤0,1 mg/l.

Category Chronic 2: Chronic NOEC or ECx (for fish)≤1 mg/l and/or Chronic NOEC or ECx (for crustacea)≤1 mg/l and/or Chronic NOEC or ECx (for algae or other aquatic plants)≤1 mg/l.

The substance is not rapidly degradable and the available short-term and long-term toxicity tests to fish, aquatic invertebrate and algae fixed effect levels that do not meet these classification criteria.Therefore, the substance is not classified for aquatic toxicity according to the CLP Regulation (EC) no. 1272/2008.