5-(diisopropylamino)-2-[[4-(dimethylamino)phenyl]azo]-3-methyl-1,3,4-thiadiazolium trichlorozincate(1-)

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.096 µg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.955 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.01 µg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

11.3 µg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.405 µg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.041 µg/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:

0.025 µg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

No long-term studies were available. Available short term studies showed LC50 (96h) on fish of 12.5 mg/l, EC50 (48h) on daphnia = 0.0955 mg/l and EC50 (72h) on aquatic plants of 3.52 mg/l. The lowest value, i.e. EC50 = 0.0955 mg/l, was used in the calculation of PNEC_water .

Assessment factors of 1000 and 10000 were used for fresh water and marine water, respectively.

The derivation of PNEC_{water, intermittent}was done by applying an assessment factor of 100 to the lowest value obtained in at least three short-term aquatic toxicity studies from three trophic levels, i.e. 0.0955 mg/l.

The value of PNEC_stpwas derived using the EC10 value determined in a toxicity study on microorganisms, i.e. 0.113 mg/l, by applying an assessment factor of 10.

Due to the lack of ecotoxicological data, PNEC_sedimentfor fresh water and marine water were calculated using equilibrium partitioning method. This method uses PNEC_waterfor 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 1.06 m³/m³. A correction factor of 4.6 from wet weight to dry weigth was applied to obtain the final PNEC_sediment.

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 PNEC_soilwas 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 PNEC_soil, PNEC_waterfor 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 0.395 m³/m³. A correction factor of 1.13 from wet weight to dry weight was applied to obtain the final PNEC_soil.

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 P_ow 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 P_ow of -0.3993, test substance was considered as not hazardous with respect to secondary poisoning.

Conclusion on classification

According to the CLP Regulation (EC 1272/2008), a substance shall be classified as category acute 1 (H400) when:

96 hr LC50 (for fish) < 1 mg/l and/or

48 hr EC50 (for crustacea) < 1 mg/l and/or

72 or 96 hr ErC (for algae or other aquatic plants) < 1 mg/l.

 

Moreover, if adequate chronic toxicity data is not available, a substance shall be classified as category chronic 1 (H410) when:

96 hr LC50 (for fish) < 1 mg/l and/or

48 hr EC50 (for crustacea) < 1 mg/l and/or

72 or 96 hr ErC (for algae or other aquatic plants) < 1 mg/l

and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, the log Kow ≥ 4).

Based on the available information, target substance is classified in category 1 for aquatic acute toxicity (H400) and aquatic chronic toxicity (H410).