Diphosphoric acid, copper salt

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Remarks:

heterotrophic respiration inhibition, nitrification inhibition and effects on ciliated protozoa

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Please refer to read across justification in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Dose descriptor:

NOEC

Effect conc.:

0.23 mg/L

Nominal / measured:

not specified

Conc. based on:

element (dissolved fraction)

Remarks on result:

other: No further data was provided.

Validity criteria fulfilled:

not applicable

Conclusions:

High quality effect endpoints on microorganisms are available for: 1) heterotrophic respiration inhibition, 2) nitrification inhibition and 3) effects on ciliated protozoa from sewage treatment plants. Across endpoints/ studies 0.23 mg dissolved Cu/L was considered as the most reliable NOEC.

Description of key information

High quality effect endpoints on microorganisms are available for: 1) heterotrophic respiration inhibition, 2) nitrification inhibition and 3) effects on ciliated protozoa from sewage treatment plants. Across endpoints/ studies 0.23 mg dissolved Cu/L was considered as the most reliable NOEC.

Additional information

Data are available on a number of substances containing inorganic copper and read-across is justified on the basis that for the purposes of assessing the ecotoxicology of Copper (II) pyrophosphate (copper(2+) diphosphate) the chemical species of interest is copper. As such studies referring to soluble copper ions from any source are considered to be directly relevant to Copper (II) pyrophosphate. Copper (II) pyrophosphate is considered to contribute to copper toxicity in the environment and as such the data assessment and risk assessment focusses on the copper ion as the phosphate ion is not considered to be toxic.

 

NOECs for microorganisms-STP

Data on the toxicity tests performed with aquatic bacteria and protozoa, reported as L(E)C50 and NOEC values. The following high quality publications were selected for assessing the toxic effects of copper on bacterial populations: Dutka (1983),Waara (1992), Madoni et al. (1996), Milksch and Schürmann (1988), Almanza et al. (1996), Fiebig and Noack (2004) and the results from the Cha et al. (2003) research project. The date from Sauvant et al. 1997, Schäfer et al., 1994, Girling et al., 2000 were used for assessing the effects on protozoan populations.

The exposure time among reports varied from short term batch exposures to continuous exposures. The effects endpoints on microorganisms covered are: heterotrophic respiration inhibition, nitrification inhibition and effects on ciliated protozoa.

The bacterial studies using mixed population tests (e.g. activated sludge) representative for microbial degradation in STP, resulted in NOEC values (reported as total or nominal concentrations) ranging from <0.5-1 and 5.4 mg/L for the heterotrophs and between 3.5 and >20 mg/L for the nitrifiers. The EC50 values for the micro-organisms representative for microbial degradation in STP range from 2.1 to 26 mg/L Cu (as total or nominal copper) for the heterotrophs and between 9.9 and 49.1 mg/L for the nitrifiers (as total or nominal copper). Expressed as dissolved copper concentrations, a NOEC range for heterotrophs between 0.23 and 0.45 mg/L was observed. For the nitrifiers, a NOEC range between 0.26 and >0.92 mg/L was observed.

Protozoan tests resulted in NOEC/L(E)C50 values depending on the test species and test-set-up used. The short term tests with T. pyriformis, the species recommended by the TGD/REACH (1996, revisions 2003), resulted in NOEC and EC50 (growth) values between, respectively, 3.6 - 3.8 mg/L and 8.0-10.2 mg/L nominal copper. These toxicity test results are based on short term experiments (between 2 and 4 days) performed in artificial media. The results obtained from protozoan communities were deemed to be more representative for the functioning of STPs and were therefore retained for the PNEC derivation.

Across endpoints/studies 0.23 mg dissolved Cu/L was considered as the most reliable NOEC.

 

Additional information:

A voluntary risk assessment report of copper and copper compounds has been submitted to the European Chemicals Agency by the European Copper Institute (June 2008). This report is based on the industry initiative to perform a voluntary risk assessment on a substance according to the mechanisms of the implementation of the Existing Substance Regulation (EEC) No 793/93 (ESR). The procedure was agreed by the 11thJoint Meeting of the Competent Authorities for the Implementation of Directive 67/548/EEC and ESR Regulation. Italy has been acting as a reviewing Member State for the substance and the risk assessment report has been reviewed by the Technical Committee on New and Existing Substances (TC NES) according to standard operational procedures of the Committee.

 

In accordance with the above mentioned European copper risk assessment, the environmental hazard assessment is based on tests carried out with soluble copper species. Studies reporting quantitative dose responses of Cu(II) ions, delivered from soluble copper compounds to aquatic organisms are used for this assessment.

 

The data presented are considered to be adequate and reliable for the purpose of defining an appropriate classification for the ecotoxicity of Copper (II) pyrophosphate in accordance with Regulation (EC) No.1272/2008 (EU CLP).