Sodium hydrogensulphate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

11.09 mg/L

Assessment factor:

100

PNEC freshwater (intermittent releases):

17.66 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

1.109 mg/L

Assessment factor:

1 000

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

800 mg/L

Assessment factor:

10

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

40.2 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

4.02 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

1.54 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Sodium hydrogensulfate:

Sodium hydrogensulfate just like sodium sulfate will dissociate in water to yield sodium ions and sulfate/hydrogensulfite anions in a pH-dependent equilibrium. For this reason, the PNEC values derived for sodium sulfate are adopted without change also for sodium hydrogensulfate. This approach implicitly considers that risk management measures prescribed for sodium hydrogensulfate releases to water explicitly require a pH neutralisation to account for any potential effects attributed merely to a pH shift in ambient environmental conditions.

pH tolerance of (freshwater) aquatic organisms:

Based on the OECD guidelines for aquatic toxicity tests with major taxonomic groups, i.e. algae, crustaceans (daphnids) and fish, a pH range of 6-9 is well tolerated by a variety of aquatic organisms. It is noted, however, that the tolerance to relatively low and high pH values depends on the composition of the water and acclimation of the organisms. Algae and other plants Some plants tolerate pH values below 3 (Alabaster and Lloyd, 1980). Invertebrates Some invertebrates tolerate pH values below 3 (Alabaster and Lloyd, 1980).

Fish :

Fish usually tolerate a pH range of 6-9. Most data are available on the tolerance of fish to acid pH values. A pH range of 5-6 may become lethal, as an acid discharge may liberate sufficient carbon dioxide from bicarbonate in the water either to be directly toxic, or to cause the pH range of 5-6 to become lethal. Below a pH value of 5, mortalities may be expected for many species, although some species may be acclimated to pH values as low as around 4 (Alabaster and Lloyd, 1980). The fish Umbra pygmaea, which is indigenous in North-America, can tolerate a pH value as low as 3. This fish species has been introduced in the Netherlands in the past and is the only fish species that lives in acid bogs (OVB, 2002).

Conclusion on classification

Sodium sulfate is not toxic to the environment. It is a naturally occurring substance which is reduced in the sulfur cycle.

Sodium sulfate does not need to be classsified for the environmental hazards. Hence, based on read-across, sodium hydrogensulfate does also not need to be classified for environmental hazards.