Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
20.6 µg/L
Assessment factor:
1
Extrapolation method:
sensitivity distribution

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
6.1 µg/L
Assessment factor:
1
Extrapolation method:
sensitivity distribution

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
52 µg/L
Assessment factor:
100
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
117.8 mg/kg sediment dw
Assessment factor:
1
Extrapolation method:
sensitivity distribution

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
56.5 mg/kg sediment dw
Assessment factor:
1
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:
35.6 mg/kg soil dw
Assessment factor:
1
Extrapolation method:
sensitivity distribution

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

General considerations

Zinc and zinc compounds form a “data rich” substance group: a vast volume of information is available on the effect of zinc on the different ecotoxicity endpoints in the open scientific literature. This vast volume of ecotoxicological information was carefully scrutinised by the Rapporteur (the Netherlands) in the framework of the discussions on the EU risk assessment (RA) made under EU Regulation 793/93/EEC. In that process, the Rapporteur’s analysis of the available chronic ecotoxicity data was extensively discussed by the experts from member states and other stakeholders during the meetings of the “Technical committee on new and existing substances” (TCNES), where the data sets to be used for PNEC derivation were officially approved. The scrutiny and discussion of TCNES were focusing on the chronic data for the PNEC derivations.

For this reason, we will use the data used in the RAR as the main data source for the environmental hazard assessment. We will not come back to the decisions on data quality and relevancy that were approved by TCNES, but use the data as they were used in the RA process. Consequently, we will use for the current analysis the data that were considered useful for PNEC derivation in the RAR as such. At the same time, we consider the data that were found not useful in the RA process also as such and we will not use them for the current analysis, neither. Given the vast amount of data, we have only reported the useful data in the IUCLID V file; the data not considered useful in the RA process have been summarised in the RAR (European Commission – Joint Research Centre, Institute for Health and Consumer Protection, Risk Assessment Report Zinc metal, Final report, 2008).

The datasets from the RAR have been complemented with relevant, reliable information that became available after the closure of the RA databases. These data have been checked according to the same principles as set out in the RA. They are also reported under IUCLID V and used for the present hazard assessments.

There are two exceptions to this general approach:

1) The analysis of the data for marine ecotoxicity. The marine ecotoxicity data in the RAR were not scrutinised for quality and relevancy since it was not an endpoint considered under the RA process. Therefore the raw dataset from the RAR was carefully checked, and completed with new data of good quality and relevancy. The PNEC for marine waters was subsequently derived.

2) In contrast to the discussion on the chronic freshwater ecotoxicity data, the acute aquatic ecotoxicity data were scrutinised and discussed in less detail during the risk assessment process. Yet, the quality and relevancy of these data is of equal if not even more importance because (in contrast to the PNEC derivation, where all the chronic data are used in a species sensitivity distribution), one single value can define the ecotoxicity reference value for classification. For this reason, the acute aquatic ecotoxicity data mentioned in the RAR were rechecked

for quality and relevancy. As such, all data considered useful in the RA and answering the criteria for reliability/relevancy were considered in the present analysis also; data that were considered not useful in the RA were not used, nor reported in IUCLID (they are reported in the RA,

(European Commission – Joint Research Centre, Institute for Health and Consumer Protection, Risk Assessment Report Zinc metal, Final report, 2008).

Since the acute aquatic toxicity dataset of the RA was closed quite early in the RA process (most recent reference 1996), this dataset was also significantly updated. The change in reference value resulting from this revision is not influencing the classifications for aquatic toxicity effect, that were agreed at EU level. However, it was considered important to re-consider the database and the ecotoxicity reference concentration derived from it, since this may influence the M-factor and, consequently, the classification of preparations.

In accordance to the scientific approach, followed in the EU RA process, two approaches are key to the zinc hazard assessment:

1) A basic assumption made in this hazard assessment and throughout this CSR, (in accordance to the same assumption made in the EU RA process) is that the ecotoxicity of zinc and zinc compounds is due to the Zn++ ion. As a consequence, all aquatic, sediment and terrestrial toxicity data in this report are expressed as “zinc”, not as the test compound as such, because ionic zinc is considered to be the causative factor for toxicity. A further consequence of this is that all ecotoxicity data obtained on different zinc compounds, are mutually relevant for each other. For that reason, the available ecotoxicity databases related to zinc and the different zinc compounds are combined before calculating the PNECs. The only way zinc compounds can differ in this respect is in their capacity to release zinc ions into (environmental) solution. That effect is checked eventually in the transformation/dissolution (T/D) tests and may result in different classifications.

2) Zinc is a natural component of the earth’s crust and present in natural background concentration in all environmental compartments. Because of the importance of the natural background, the “added risk concept” has been used in the RAR on zinc (European Commission – Joint Research Centre, Institute for Health and Consumer Protection, Risk Assessment Report Zinc metal, Final report, 2008).

In this approach both the "Predicted Environmental Concentration"(PEC) and the "Predicted No Effect Concentration" (PNEC) are determined on the basis of the added amount of zinc, resulting in an “added Predicted Environmental Concentration” (PECadd) and “added Predicted No Effect Concentration” (PNECadd), respectively. The use of the added risk approach implies that only the anthropogenic amount of a substance, i.e. the amount added to the natural background concentration, is considered to be relevant for the risk assessment. Thus, a possible contribution of the natural background concentration to toxic effects is ignored (RAR, European

Commission – Joint Research Centre, Institute for Health and Consumer Protection, Risk Assessment Report Zinc metal, Final report, 2008).

So, for zinc, all PNECs are expressed as “added” concentration to the background.

The use of the added risk approach implies that for risk characterisation, the natural background needs to be taken into account when evaluating monitored concentrations in the environment. The correct assessment of natural background is thus important.

Conclusion on classification

Based on data obtained from a 72 hours algae toxicity study and from a biodegradation screening study zinc diricinoleate is not classified as dangerous for the environment according to Directive 67/548/EEC and according to GHS.