Registration Dossier

Diss Factsheets

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
0.1 mg/L
Assessment factor:
1 000
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
1 mg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.01 mg/L
Assessment factor:
10 000
Extrapolation method:
assessment factor

STP

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

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
0.375 mg/kg sediment dw
Extrapolation method:
equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.037 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:
0.016 mg/kg soil dw
Extrapolation method:
equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
PNEC oral
PNEC value:
13.3 mg/kg food
Assessment factor:
300

Additional information

PNEC´s were derived from the most sensitive test available for each compartment/endpoint. The PNECs aqua were derived from the most sensitive test for the aquatic compartment, the short-term toxicity to algae. However, due to the strong acidic (pH= 0.3, pKa = 3.12) properties of Glyoxylic Acid 50%, a marked pH drop (4.36 -4.71) of the algal medium (pH 7.52 -9.96) was observed after addition of the highest test substance concentration (100 mg/L), which resulted in an EC50 (72h) of 67.5 mg/L (nominal). To circumvent this pH-shift, pH adjustment of the test medium with NaOH was made. Thus, the pH value remained between 7.64 and 6.90, which resulted in an EC50 value of >100 mg/L. Due to the application of assessment factors > 100 for the derivation of PNECs, effect on the pH-value of environmental media at Glyoxylic Acid concentrations in the range of the PNEC can be excluded. Thus, the EC50 obtained in the buffered test medium can be used to derive the PNECs.

Conclusion on classification

Glyoxylic Acid 50% is readily biodegradable. Algae (Scenedesmus subspicatus) is the most sensitive species with an EC50 value of 65 mg/L in algal medium without pH-adjustment and 100 mg/L, when the pH of the algal medium was adjusted after the addition of the test substance. Thus Glyoxylic Acid 50% does not fulfill the criteria for classification and labelling as "hazardous to the aquatic environment" according to Directive 67/548/EEC and Regulation 1272/548/EEC.